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1
Thai, Huu-Tai, Trung-Kien Nguyen, Seunghye Lee, Vipulkumar Ishvarbhai Patel, and Thuc P. Vo. "Review of Nonlinear Analysis and Modeling of Steel and Composite Structures." International Journal of Structural Stability and Dynamics 20, no. 04 (April 2020): 2030003. http://dx.doi.org/10.1142/s0219455420300037.
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Structural steel frames exhibit significantly geometric and material nonlinearities which can be captured using the second-order inelastic analysis, also known as advanced analysis. Current specifications of most modern steel design codes, e.g. American code AISC360, European code EC3, Chinese code GB50017 and Australian code AS4100 permit the use of advanced analysis methods for the direct design of steel structures to avoid tedious member capacity checks. In the past three decades, a huge number of advanced analysis and modeling methods have been developed to predict the behavior of steel and composite frames. This paper presents a comprehensive review of their developments, which focus on beam-column elements with close attention to the way to capture geometric and material nonlinearity effects. A brief outline of analysis methods and analysis tools for frames was presented in the initial part of the paper. This was followed by a discussion on the development of displacement-based, force-based and mixed beam elements with distributed plasticity and concentrated plasticity models. The modeling of frames subjected to fire and explosion was also discussed. Finally, a review of the beam-column models for composite structures including concrete-filled steel tubular (CFST) columns, composite beams and composite frames was presented.
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Budvytis, Marius, Alfonso Cobo Escamilla, and Linas Juknevičius. "ANALYSIS OF SHEAR DESIGN RECOMMENDATIONS FOR FRP REINFORCED CONCRETE BEAMS." Engineering Structures and Technologies 10, no. 2 (November 13, 2018): 46–57. http://dx.doi.org/10.3846/est.2018.6478.
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Research shows that most shear design models for concrete beams reinforced with FRP reinforcement provide conservative results that leads to excessive amounts of reinforcement and increased overall cost of such construction. This paper presents comparative analysis of current shear design models for concrete beams reinforced with longitudinal FRP reinforcement and FRP stirrups. New analytical shear design model, developed by Valivonis et al., has been included in the analysis. A database with 88 specimens reinforced with FRP reinforcement was compiled in order to verify the accuracy of the proposed model by Valivonis et al. It is shown that proposed shear design model yields quite accurate and consistent results as an average of Vexp / Vpred values is 0.98 and coefficient of variation is 26.0% for this model.
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Park, Seon-Chee, Won-Kee Hong, Sunkuk Kim, and Xiangyu Wang. "Mathematical Model of Hybrid Precast Gravity Frames for Smart Construction and Engineering." Mathematical Problems in Engineering 2014 (2014): 1–14. http://dx.doi.org/10.1155/2014/916951.
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The structural stability, constructability, economic feasibility, environmental-friendliness, and energy efficiency of hybrid composite frame systems have been demonstrated by practical application and research. A hybrid composite frame system combines the economy of precast concrete structures with the constructability of steel frame structures, including erection speed. Novel composite frames will ultimately maximize the efficiency of structural design and facilitate construction. This paper presents hybrid precast frames, which are precast composite frames based on a simple connection between precast concrete columns and beams. The hybrid precast frames designed to resist gravity loading consist of PC columns, PC beams, and steel inserted in the precast members. Steel sections located between the precast columns were simply connected to steel inserted at each end of the precast beams. Dynamic analysis of a 15-story building designed with the proposed composite frame was performed to determine the dynamic characteristics of a building constructed of hybrid frames, including frequencies and mode shapes.
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Luévanos Rojas, Arnulfo. "Numerical experimentation for the optimal design of reinforced rectangular concrete beams for singly reinforced sections." DYNA 83, no. 196 (April 20, 2016): 134–42. http://dx.doi.org/10.15446/dyna.v83n196.48031.
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<p>This paper presents a model for the optimal design of reinforced rectangular concrete beams for singly reinforced sections. It develops an analytical approach to the problem, based on a criterion of minimum cost and minimum weight design with a reduced number of design variables. Representative examples are presented to illustrate the applicability of the formulation in accordance with building code requirements for structural concrete (ACI 318S-13), including the comments on the standards. A comparison is made between the optimal design solution and current design practice for reinforced rectangular concrete beams. The optimal solution for the design of reinforced rectangular concrete beams shows clearly that significant savings can be made in the costs of the construction materials used – i.e. reinforcement steel and concrete. In addition, the problem formulation can be applied using a nonlinear mathematical programming format.</p>
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Nguyen, N. T., D. J. Oehlers, and M. A. Bradford. "Models for the Flexural Peeling of Angle Plates Adhesively Bonded to R-C Beams." Advances in Structural Engineering 1, no. 4 (October 1998): 287–300. http://dx.doi.org/10.1177/136943329800100405.
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The strength and stiffness of existing reinforced concrete beams may be enhanced by adhesively bonding angle section members to the soffit/side edges of reinforced concrete (RC) beams. This retrofitting is extremely important in improving the seismic performance of under reinforced RC beams which may suffer ductility problems in earthquakes, or whose strength has deteriorated due to unfavourable environmental factors. This paper develops generic mathematical models for simulating the debonding of angle plates glued to the edges of RC beams as a result of flexural peeling. It is shown that to achieve an accurate model the derivations are quite complex, but the experimental calibration renders the presentation of the model in a simple format. The models have been validated with experimental results.
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Huang, Dongzhou, and Mohsen Shahawy. "Analysis of Tensile Stresses in Transfer Zone of Prestressed Concrete U-Beams." Transportation Research Record: Journal of the Transportation Research Board 1928, no. 1 (January 2005): 134–41. http://dx.doi.org/10.1177/0361198105192800115.
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Prestressed U-beam bridges compare favorably in cost and appearance to traditional concrete I-beam bridges. Consequently, U-beam bridges are gaining in popularity and usage, especially when aesthetic issues are deemed important. U-beam bridges first appeared in Florida in 2000; however, during construction, cracks developed in the webs of the U-beams. This paper presents results of an analysis of representative cracking of U-beams and proposes a practical method for the transfer zone stirrup design. For the purpose of the analysis, the U-beam is divided into a series of finite shell-plate elements, and the prestressing tendons are simulated as a number of concentrated forces. Two different mechanical models of the U-beams are developed on the basis of the stages of construction. Analytical results show that high tensile stresses occur in the end zone of the U-beam because of the prestressing tendons and that these tensile stress must be properly considered in bridge design. The research results are applicable to the design of prestressed U-beams and similar types of prestressed girders.
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Marian, Stănescu Răzvan. "Steel and Concrete Elasto-Plastic Models at Bridges with Steel Beams Embedded in Concrete." Romanian Journal of Transport Infrastructure 7, no. 1 (July 1, 2018): 64–76. http://dx.doi.org/10.2478/rjti-2018-0004.
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Abstract For new railway bridges with short spans (L ≤ 35.00 m) superstructures with steel beams embedded in concrete are recommended or used, which can ensure the requirements of strength and stiffness in particular, regardless of velocity. They are built relatively easily compared to reinforced concrete structures or steel structures, they have high durability if designed, built and maintained correctly and don’t have high sensitivity to fatigue degradation in service. They are also used for road bridges when it is desired to achieve a reduced construction height. In all the design prescriptions used so far for structures with steel beams embedded in concrete, the calculation is a simplified one, made on a single insulated longitudinal beam of the deck, if certain conditions related to the geometry of the structure are met (obliquity, curvature). Simplifications are also made regarding the state of deformation of the decks made in this constructive solution by introducing an effective moment of inertia in the displacement calculation, as an average of the inertia moments of the cross section considered to be cracked and respectively un-cracked. The article aims to validate steel and concrete elasto-plastic models, based on an experiment from the technical literature, necessary for complex analyses of the percentage of concrete involved in the stiffness of the cross-sections, in case of bridges with steel beams embedded in concrete.
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Sundar, N., PN Raghunath, and G. Dhinakaran. "Flower pollination-based optimal design of reinforced concrete beams with externally bonded of FRPS." Advanced Composites Letters 29 (January 1, 2020): 2633366X2096249. http://dx.doi.org/10.1177/2633366x20962499.
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The optimal design of reinforced concrete beams (RCBs) and structures with an objective of improving the chosen performances is an important problem in the field of construction works. Recently, the concrete beams, structures, and walls are strengthened externally by bonding fiber-reinforced polymer strips (FRPS). Usually, FRPS are employed in rehabilitation of existing beams, bridges, and other structural elements. This article modifies the problem of designing new RCBs with appropriate selection of FRPS with a goal of exploiting the benefits of FRPS such as higher tensile strength, better corrosion resistance, higher stiffness-to-weight ratio, and longer life. It, firstly, proposes an artificial neural network-based mathematical model for assessing the performances of RCBs bonded with FRPS from the data obtained from 69 FRPS-glued RCBs and then develops an optimal design procedure employing flower pollination-based optimization, which is imitated from the pollination process of plants, for obtaining design parameters of FRPS-glued RCBs with a view of enhancing both the ultimate load and the deflection ductility. It presents optimal design parameters of five FRPS-glued RCBs and experimentally validates the performances.
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Utkin, Vladimir S., and Sergey A. Solovyev. "RELIABILITY ANALYSIS OF EXISTING REINFORCED CONCRETE BEAMS ON NORMAL CRACK LENGTH CRITERION." International Journal for Computational Civil and Structural Engineering 13, no. 2 (June 30, 2017): 56–63. http://dx.doi.org/10.22337/2587-9618-2017-13-2-56-63.
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The article discusses a problem of the crack length influence on the reliability (safety) of reinforced concrete beams under conditions of limited statistical information about controlled parameters in the design mathematical models of limit state. Numerical examples revealed the possibility of practical application of the reliability analysis methods for inspections and determining the category of the technical condition of buildings and structures. The article offers the methods for reliability (probability of non-failure) analysis and the residual resource of reinforced concrete beams according to the criterion of the normal crack length in the tensile zone of reinforced concrete beams. The methods of reliability analysis constructed on the basis of possibility theory and fuzzy set theory. The algorithms of reliability analysis of reinforced concrete beams are presented on numerical examples of reliability analysis.
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Kvocak, Vincent, Daniel Dubecky, and Viktoria Kozlejova. "Experimental Verification of Design Models in a Static and Dynamic Loading Test." Key Engineering Materials 763 (February 2018): 394–99. http://dx.doi.org/10.4028/www.scientific.net/kem.763.394.
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Nowadays more and more often investors and constructors are building constructions by combining two of the most common materials: reinforced concrete and steel. By understanding their behavior we can squeeze a mountain of used material with better results. They make it possible to take advantage of good mechanical properties of concrete in compression and steel in tension. One of the commonest types of composite structures is deck bridges with encased filler beams. These types of construction have been employed in Slovakia and all over Europe without any major change since the beginning of the 19th century. Several steel sections of modified shapes and dimensions were designed and tested in the Laboratories of the Institute of Structural Engineering at the Technical University in Košice. The main goal was to design and experiment with deck bridges made of various sections so as to maximise their cost-effectiveness by reducing the amount of steel consumed. Based on theoretical analyses, specimens were prepared in the laboratory, consisting of a variety of fully encased steel sections. It was cast into the prepared steel formwork placed on a fixed bearing plate so as to prevent deflection of composite beams during the concreting process.
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Jeong, Chan-Yu, Hyeong-Gook Kim, Sang-Woo Kim, Kang-Seok Lee, and Kil-Hee Kim. "Size effect on shear strength of reinforced concrete beams with tension reinforcement ratio." Advances in Structural Engineering 20, no. 4 (July 3, 2016): 582–94. http://dx.doi.org/10.1177/1369433216658486.
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It is well known that shear stress at peak of reinforced concrete beams decreases with increasing effective depth. Thus, several existing design codes and models have included various forms of formulas considering the size effect on shear strength of reinforced concrete beams; however, past experimental researches show that tension reinforcement ratio is also associated with the shear strength of reinforced concrete beams. To examine the effect of tension reinforcement ratio and effective depth on shear strength of reinforced concrete beams, this study has conducted experiments in which the effective depth (150, 300, 500, and 780 mm) and tension reinforcement ratio (1%, 2%, and 3%) are employed as variables. Besides, a formula for the shear strength considering both variables is proposed based on data samples collected from the present experiment and previous research. The proposed formula gives predictions comparable to the results of existing shear tests. Furthermore, rational predictions are made for effective depth of beams, compressive strength of concrete, shear span-to-depth ratio, and even tension reinforcement ratio exceeding 3%.
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Nouri, Assia, Mostefa Hamrat, Bensaid Boulekbache, Said Nouri, Farid Bouziadi, Abderrahim Labed, Abdelkader Haddi, and Chafika Djelal. "Quantification of shear strength in reinforced concrete beams using digital image correlation: Experimental and analytical study." Advances in Structural Engineering 24, no. 1 (July 30, 2020): 147–64. http://dx.doi.org/10.1177/1369433220944510.
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This article presents an experimental study aiming to provide reliable experimental data for the prediction of the shear strength of reinforced concrete beams without stirrups. The shear strength results obtained from the proposed model as well as those from the design codes (ACI 318, Eurocode 2 and BS 8110) are compared with the database containing 700 beams made of both high strength concrete and normal strength concrete. Furthermore, the experimental results were used to assess the contribution of each shear mechanism obtained from Chen’s, Cavagnis’s and Fernández Ruiz’s models. The contribution of these various shear-transfer actions is also quantified experimentally, using a digital image correlation. As a result, the measured contributions of dowel action, aggregate interlock and compression zone to the total shear resistance were estimated as 45% to 50%, 20% to 35% and 17% to 31%, respectively, for high strength concrete beams. On the contrary, the average test-to-predicted contribution of the shear-transfer action ratio determined by the Chen formula is 1.15 for short beams, whereas the Fernández Ruiz and the Cavagnis models yielded average ratios of 1.04 and 1.52, respectively, for slender beams. The proposed formulae give a rational prediction for either both short and slender beams, and yield accurate and consistent results compared to the other models used in this study, with a lowest average value of the test-to-predicted at 1.08 and that of the coefficient of variation at 23.06%, particularly for short beams. However, ACI 318 is the only code that does not take into account the size effect, leading to a severe underestimation of the shear strength for short beams.
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Ly, Hai-Bang, Tien-Thinh Le, Huong-Lan Thi Vu, Van Quan Tran, Lu Minh Le, and Binh Thai Pham. "Computational Hybrid Machine Learning Based Prediction of Shear Capacity for Steel Fiber Reinforced Concrete Beams." Sustainability 12, no. 7 (March 30, 2020): 2709. http://dx.doi.org/10.3390/su12072709.
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Understanding shear behavior is crucial for the design of reinforced concrete beams and sustainability in construction and civil engineering. Although numerous studies have been proposed, predicting such behavior still needs further improvement. This study proposes a soft-computing tool to predict the ultimate shear capacities (USCs) of concrete beams reinforced with steel fiber, one of the most important factors in structural design. Two hybrid machine learning (ML) algorithms were created that combine neural networks (NNs) with two distinct optimization techniques (i.e., the Real-Coded Genetic Algorithm (RCGA) and the Firefly Algorithm (FFA)): the NN-RCGA and the NN-FFA. A database of 463 experimental data was gathered from reliable literature for the development of the models. After the construction, validation, and selection of the best model based on common statistical criteria, a comparison with the empirical equations available in the literature was carried out. Further, a sensitivity analysis was conducted to evaluate the importance of 16 inputs and reveal the dependency of structural parameters on the USC. The results showed that the NN-RCGA (R = 0.9771) was better than the NN-FFA and other analytical models (R = 0.5274–0.9075). The sensitivity analysis results showed that web width, effective depth, and a clear depth ratio were the most important parameters in modeling the shear capacity of steel fiber-reinforced concrete beams.
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Whitworth, Alex H., and Konstantinos Daniel Tsavdaridis. "Genetic Algorithm for Embodied Energy Optimisation of Steel-Concrete Composite Beams." Sustainability 12, no. 8 (April 13, 2020): 3102. http://dx.doi.org/10.3390/su12083102.
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The optimisation of structural performance is acknowledged as a means of obtaining sustainable structural designs. A minimisation of embodied energy of construction materials is a key component in the delivery of sustainable future designs. This study attempts to understand the relationship between embodied energy and structural form of composite floor plates for tall buildings, and how this form can be optimised to minimise embodied energy. As a search method based upon the principles of genetics and natural selection, genetic algorithms (GA) have previously been used as novel means of optimising composite beams and composite frames for cost and weight objective functions. Parametric design models have also been presented as optimisation tools to optimise steel floor plates for both cost and embodied carbon. In this study, a Matlab algorithm is presented incorporating MathWorks global optimisation toolbox GA and utilising Eurocode 4 design processes to optimise a composite beam for five separate objective functions: maximise span length; minimise beam cross-section; minimise slab depth; minimise weight; minimise deflected shape for each of the objective functions. Candidate designs are to be assessed for embodied energy to determine individual relationships. This study shows that it is possible to reduce the embodied energy of steel–concrete composite beams by genetic algorithm optimisation whilst remaining compliant to given design codes.
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Bacinskas, Darius, Deividas Rumsys, Aleksandr Sokolov, and Gintaris Kaklauskas. "Deformation Analysis of Reinforced Beams Made of Lightweight Aggregate Concrete." Materials 13, no. 1 (December 19, 2019): 20. http://dx.doi.org/10.3390/ma13010020.
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In the present trend of constructing taller and longer structures, the application of lightweight aggregate concrete is becoming an increasingly important advanced solution in the modern construction industry. In engineering practice, the analysis of lightweight concrete elements is performed using the same algorithms that are applied for normal concrete elements. As an alternative to traditional engineering methods, nonlinear numerical algorithms based on constitutive material models may be used. The paper presents a comparative analysis of curvature calculations for flexural lightweight concrete elements, incorporating analytical code methods EN 1992-1 and ACI 318-19, as well as a numerical analysis using the constitutive model of cracked tensile lightweight concrete recently proposed by the authors. To evaluate the adequacy of the theoretical predictions, experimental data of 51 lightweight concrete beams of five different programs reported in the literature were collected. A comparison of theoretical and experimental results showed that the most accurate predictions are obtained using numerical analysis and the constitutive model proposed by the authors. In the future, the latter algorithm can be used as a reliable tool for improving the design standard methods or numerical modeling of lightweight concrete elements subjected to short-term loading.
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Somma, Giuliana, Alessandro Pieretto, and Alberto Dassie'. "Steel to Concrete Bond Transferring in CFST Columns Connected to Beams through the Concrete." Applied Mechanics and Materials 847 (July 2016): 513–20. http://dx.doi.org/10.4028/www.scientific.net/amm.847.513.
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An important innovation in structural design in the last thirty years has been the use of steel-concrete composite columns, with particular diffusion of tubular profiles. These elements are known in the technical Literature as concrete filled steel tube (CFST) and the metal profiles that characterize the external jacket are usually circular, square or rectangular.A relevant issue that must be considered is the transfer of shear stresses by adhesion between steel and concrete in composite columns. The problem of adhesion, and thus its formulation, depends primarily on the type of technology used to connect beams to columns. In particular, two different models can be produced: the first case where the beams are connected only to the metal external jacket of the pillar (i.e. steel beams connected with bolted flanges to the column), and the second where beams and columns are connected also in the concrete matrix (i.e. the case of beams in steel-concrete technology, or traditional reinforced concrete beams).International Standards, regarding the problem of adhesion in jacketed columns, only referee to the first connection type, giving a constant value for adhesion coefficient along the transferring length, with no dependence to the size of the section, and indicate transferring lengths independently from the type of beam-to-column connection and the shape of the section. In the Paper are hence proposed expressions that quantify the fundamental values that govern the action transfer mechanism by adhesion in CFST, such as the transfer length, the perimeter of the active transfer and the shear stress distribution, as a function of the slenderness ratio and of the type of connection adopted. All this has been carried in order to produce a model for the estimation of bond stresses for the second of the two construction system mentioned above.
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Tena-Colunga, Arturo, Hans I. Archundia-Aranda, and Luis Angel Urbina-Californias. "Equations for Shear Design of Continuous Reinforced-Concrete Haunched Beams Based on Stress Fields and Truss Models." Practice Periodical on Structural Design and Construction 25, no. 3 (August 2020): 04020012. http://dx.doi.org/10.1061/(asce)sc.1943-5576.0000482.
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Karpiuk, I. A., A. S. Tselikova, V. M. Karpiuk, A. A. Khudobych, D. S. Korchevnyi, and V. G. Kravchuk. "DESIGN MODELS OF THE BEARING CAPACITY OF THE SUPPORT SECTIONS OF BASALT-CONCRETE BEAM STRUCTURES." Bulletin of Odessa State Academy of Civil Engineering and Architecture, no. 82 (March 4, 2021): 27–36. http://dx.doi.org/10.31650/2415-377x-2021-82-27-36.
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Abstract. In the past decade, structures with non-metallic composite reinforcement (FRP) find more and more widespread use in construction practice, especially in buildings and structures for special purposes. Due to its high strength, resistance to chemical and physical corrosion, dielectric and diamagnetic properties, low weight and low thermal conductivity, FRP is increasingly replacing steel reinforcement. However, the wider use of concrete structures with FRP is constrained by insufficient knowledge of the features of their work, insufficient regulatory support and little experience in operating these facilities. Practice has shown the promise and economic feasibility of using FRP in road, hydraulic engineering, transport construction, in the construction of bridge spans, treatment facilities, chemical and food industry facilities, and foundations in an aggressive soil environment. At the same time, the prospects for using basalt-plastic reinforcement (BFRP) are primarily due to the low cost of the main raw material, basalt fibers, due to the presence of significant reserves of basalt in the world. The basic principles of calculation of bending structures reinforced with FRP, in all foreign standards, as well as in the domestic Manual, are the same as for elements with steel reinforcement. The design models of the bearing capacity of the bearing sections of concrete beams reinforced with BFRP are considered. The bearing capacity of inclined sections of elements with large and medium shear spans should be determined by an inclined crack using variable coefficients , taking into account the real length of a dangerous inclined crack , a significant reduction in tensile stresses in transverse reinforcement to . The bearing capacity of the support sections with small shear spans must be determined as for short cantilevers along an inclined compressed strip between the concentrated force and the support using a variable coefficient . This approach provides satisfactory convergence between the calculated and experimental values of the bearing capacity of inclined sections (coefficient of variation BFRP.
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Hoan, Pham Thai, and Nguyen Minh Tuan. "Effect of uniform temperature load on design of long reinforced concrete structures without expansion joints." Journal of Science and Technology in Civil Engineering (STCE) - NUCE 15, no. 3 (August 16, 2021): 68–80. http://dx.doi.org/10.31814/stce.nuce2021-15(3)-06.
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This study presents an investigation on the design of long reinforced concrete (RC) structures subjected to uniform temperature load by considering three RC frame building models with different lengths of 45 m, 135 m, and 270 m using Etabs. The uniform temperature load is considered being the change from the annual average highest to lowest air temperature at the construction site in the case of unavailable temperature data of concrete. The analysis results indicate that the uniform temperature load mainly influences on the internal forces of RC members at storey 1 and slightly effects on the internal forces of RC members at storey 2. For short-length RC structures, the effect of temperature load can be ignored in the design of RC elements, whereas it must be taken into account in design of slab, beams and some column positions at storey 1 of medium-length and long RC structures without expansion joints. For the present RC frame building models, the required slab reinforcement in long direction increases about 33.4% for medium-length RC structures (135 m) and about 48.2% for long RC structures (270 m) without expansion joints. The required reinforcement for positive moment at mid-span increases from 33.7 to 39.4%, whereas the total required reinforcement for negative moment at the supports of beams increases from 19.4 to 34.9% in long direction of 270 m long RC structures without expansion joints due to uniform temperature load. Column design of long RC structures without expansion joints under uniform temperature load must be concerned, especially for columns in the corners.
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Somina, Yu A., and V. M. Karpiuk. "DEFORMABILITY OF REINFORCED CONCRETE BEAMS UNDER THE ACTION OF CYCLIC LOADING." Bulletin of Odessa State Academy of Civil Engineering and Architecture, no. 83 (June 4, 2021): 38–46. http://dx.doi.org/10.31650/2415-377x-2021-83-38-46.
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The aim of the article is an experimental research of the influence of low-cycle sign-constant loading, as well as the most significant design factors on the deformability of reinforced concrete beam elements. In this regard, for experimental research, the authors developed a four-factor three-level Boxing plan B4. The experimental factors of the plan were varied according to the literature review, which showed that the most significant factors are the following: the value of the relative shear span a/h0, the concrete class C, the value (amount) of transverse reinforcement on the beams support sections ρsw, the level of sign-constant loading η. The samples were tested according to the scheme of a single-span beam, alternately loaded with two centre-point forces. The number of cycles of sign-constant loading was accepted as 10. According to the results of the experiment, using the COMPEX program, adequate mathematical models of the basic parameters of reinforced concrete specimens-beams deformability under the action of low-cycle sign-constant loading were derived, that reflect the influence of these factors both individually and in interaction with each other. Analyzing these models, the features of the development of tensile reinforcement and compressed concrete deformations, as well as beams deflections in the specified conditions, were established. In particular, the factors that have the greatest influence on deformations and deflections are the relative shear span and the level of low-cycle loading. Thus, with their increase, the relative deformations of tensile reinforcement increase by 51% and 52%, the relative deformations of compressed concrete by 40% and 37%, accordingly, by series. The increase of deflections is 43% and 40% with an increase of relative shear span and 38% and 12% with an increase of loading level, accordingly, by series.
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Vojtasik, Karel, Eva Hrubesova, Marek Mohyla, and Lukáš Duris. "Design and Evaluation of a Subterranean Work Lining from Layers of Shotcrete and Steel Arch." Advanced Materials Research 1020 (October 2014): 347–50. http://dx.doi.org/10.4028/www.scientific.net/amr.1020.347.
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A steel concrete lining is today the common ground massive retaining structure implemented shortly after the excavation of an opening. The constituent elements of the steel concrete lining are layers of shotcrete and steel arch frames. This simple structure has many unique features which set it apart from the conventional reinforced concrete constructions. Without simplification these features doesn’t allow to carry out design and evaluation of steel concrete lining by relevant design and evaluation methods convenient to the conventional reinforced concrete constructions. The main differences are construction process, yielding curve of structure and determination of external load. In the case of a steel concrete lining its external load is product of mutual work of both the ground massive and the lining. The value of load depends on the yielding curves of the lining and the ground massive. The yielding curve of a ground massive is objective and conditioned on strength strain properties of ground massive and primary stress state. The yielding curve of a steel concrete lining relates lining design specification. The process of construction affects the value of load too. The article analyzes the steel concrete lining focusing the influence of lining design parameters on its yielding curve. It looks for a way to control the ground massive behavior and as well as to engage it more in an effort with lining to stabilize subterranean work. The themes of the analysis are: static and deformation parameters of the cross-section of the steel concrete lining with regard to the construction stage and dependency of hardening shotcrete; interaction between of steel concrete lining and ground massive based on yielding curves; assessment of a stress state across the steel concrete lining section in the steel concrete lining constituent elements. The analysis is carried out on mathematical models that combine analytical and numerical methods.
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Lisienkova, Liubov, Tatiana Shindina, Nina Orlova, and Liudmila Komarova. "Optimization of the Concrete Composition Mix at the Design Stage." Civil Engineering Journal 7, no. 8 (August 1, 2021): 1389–405. http://dx.doi.org/10.28991/cej-2021-03091732.
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The problem of the composition optimization of concrete mixes seems to be quite urgent as errors at the composition design stage can lead to problems of concrete at the stage of exploitation such as delamination, cracking etc. Reasonable selection of concrete mix components guarantees the required strength of concrete and reinforced concrete structures in the future. This paper investigates the influence of the concrete mix composition on the strength of concrete. Firstly, typical risks that can occur on the composition design stage have been identified through the experts' interviews. Secondly, this risks were associated with indicators and characteristics that can be tested experimentally. Running of several mathematical models has allowed to outline concrete mix parameters of highest importance and formulate an empirical equation for the dependence of the strength of the concrete mixture on the values of the coarse aggregate quality factor, the fine aggregate fraction and the consumption of the Portland cement has been proposed. As a result, a methodology for controlling the quality of concrete at the stage of the composition design has been formulated. Doi: 10.28991/cej-2021-03091732 Full Text: PDF
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Li, Zhong-Xian, Bo Zhong, Yanchao Shi, Yang Ding, and Yifei Hao. "A computationally efficient numerical model for progressive collapse analysis of reinforced concrete structures." International Journal of Protective Structures 10, no. 3 (June 13, 2019): 330–58. http://dx.doi.org/10.1177/2041419619854768.
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Although marked advancements have been achieved to improve the computer power, progressive collapse analysis of large-scale reinforced concrete structures is still time-consuming or even impractical. In this study, a numerical model is proposed for efficient progressive collapse analysis of reinforced concrete structures. Recent advancements that can accurately and efficiently model the mechanical behavior of structural components are incorporated in the numerical model of reinforced concrete structure. The beams/columns, joint regions, and slabs are modeled by enhanced fiber beam element, macrojoint model, and layered shell element, respectively. In this way, the shear failure of beams/columns, failure of joints, and resistance contribution from floor slab can be taken into account for progressive collapse analysis of reinforced concrete structures. A six-story reinforced concrete frame structure is modeled using the approach proposed in this study. The progressive collapse of the structure is analyzed under column removal and direct blast loading scenarios. For comparison purpose, other popularly used finite element models are also adopted to carry out numerical simulations. The proposed model is proven to yield accurate simulation results with the least cost of time among all models. Based on the proposed model, parametric simulations are performed to investigate effective measures to improve the structural resistance to progressive collapse. It is found that increasing longitudinal reinforcement ratio in beams and columns can increase the catenary action capacity, but hardly increases the compressive arch action capacity. Moreover, the steel mesh reinforcement at top layer of slabs plays a significant role in resisting progressive collapse of reinforced concrete structures, which should be considered in design to resist progressive collapse.
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Park, Aaron, Richard Finley, and John Cater. "Predicting horizontal impact sound transmission for complex floor systems: Using EN 12354-2:2000, finite element method, statistical energy analysis and analytical techniques." Building Acoustics 24, no. 1 (March 2017): 53–73. http://dx.doi.org/10.1177/1351010x17691777.
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Modifications to the New Zealand Building Code are currently being considered, which may create a requirement to assess impact noise horizontally not just vertically. The test would be similar to vertical tests as described in ISO 140-7:1998, but sound pressure levels are proposed to be measured instead in the closest living space in an adjacent apartment which shares a common floor system. This work seeks to identify and validate different mathematical and computational methods for predicting the results of horizontal impact tests. Three methodologies were tested: finite element method software, statistical energy analysis and an analytical solution derived from the governing partial differential equations. These methods were applied to two different floor systems: a concrete double tee floor and a concrete floor supported by concrete beams and columns. Limitations were found for all of the methods, and caution is advised when using these to design to horizontal impact noise criteria.
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Murashkin, Vasily G. "Features of Nonlinear Deformation of Concrete." Scientific journal “ACADEMIA. ARCHITECTURE AND CONSTRUCTION”, no. 1 (March 18, 2019): 128–32. http://dx.doi.org/10.22337/2077-9038-2019-1-128-132.
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In most studies, when the problem of determining a nonlinear model of deformation of structural concrete in normal environment, or experienced a variety of destructive (aggressive, temperature, etc.) exposure, using individual mathematical apparatus and software. The main criterion in these works for the construction of the deformation model of concrete was a unique relationship "strength - modulus of elasticity". Apply the developed model for another type of concrete or experienced a destructive impact was erroneous. However, not all features of concrete deformation in the construction of models were taken into account. In particular, the gentle nature of deformation in the initial stage of loading was not taken into account. Similarly, models of nonlinear deformation of concrete in normative materials of different countries are constructed. Especially there are problems in the inspection of structures operated for along time. It is not rational to create individual models based on the algorithm created earlier. In recent studies, a number of works have noted the need to take into account the features of the initial stage ofloading of concrete and the fact that concrete from the beginning ofloading has macro and micro cracks and structural defects. But even in these works the possibility of creating a nonlinear deformation model based on experimentally obtained data when testing prototypes of generalized model was not considered. This article discusses the possibility of constructing a concrete extracted from the structure. The possibility of replacing the individual deformation models with the proposed one is shown. In the generalized model of deformation "strength and modulus of elasticity" may not coincide with the normative characteristics and it can serve as a basis for determining the stress state in the survey of operated structures and, if necessary, for the design of new ones.
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Agcakoca, E., and M. Aktas. "The Impact of the HMCFRP Ratio on the Strengthening of Steel Composite I-Beams." Mathematical Problems in Engineering 2012 (2012): 1–13. http://dx.doi.org/10.1155/2012/183906.
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Carbon fiber-reinforced polymer materials have become popular in the construction industry during the last decade for their ability to strengthen and retrofit concrete structures. The recent availability of high-modulus carbon fiber-reinforced polymer strips (HMCFRP) has opened up the possibility of using this material in strengthening steel structures as well. The strips can be used in steel bridge girders and structures that are at risk of corrosion-induced cross-sectional losses, structural deterioration from aging, or changes in function. In this study, a set of bending experiments was performed on three types of steel beams reinforced with HMCFRP. The results were used to enhance a nonlinear finite element model built with ABAQUS software. The accuracy of the mathematical models for HMCFRP, epoxy, and steel profiles was compared with the experimental results, and the ability of HMCFRP to continue carrying load from the steel beams during rupture and postrupture scenarios was observed using numerical analysis. Using these verified finite element models, a parametric analysis was performed on the HMCFRP failure modes and the quantity to be used with IPE profile steel beams. The maximum amount of HMCFRP needed for strengthening was determined, and an upper limit for its use was calculated to avoid any debonding failure of the fiber material.
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Bačinskas, Darius, Gintaris Kaklauskas, Viktor Gribniak, and Edgaras Geda. "MECHANICAL SIMULATION OF REINFORCED CONCRETE SLABS SUBJECTED TO FIRE." Technological and Economic Development of Economy 13, no. 4 (December 31, 2007): 295–302. http://dx.doi.org/10.3846/13928619.2007.9637815.
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There are many buildings and civil engineering works under construction which are at risk of fire. The fire resistance analysis of reinforced concrete structures constitutes an important part in their design. However, the analysis of the behaviour of load‐bearing members under high temperature conditions is very complicated. Various factors that influence the behaviour of the members need to be taken into account. Analytical and computation methods have been developed in the field of reinforced concrete building exposed to high temperature or accidental fire. Unfortunately, such models are computationally too demanding and their application are limited even for a simply supported reinforced concrete members (beams, plates etc). In this paper, an attempt has been made to extend application of the Flexural model to stress and strain analysis of flexural reinforced concrete members subjected to high temperature. Constitutive models and key material parameters describing thermo‐mechanical behaviour of concrete and reinforcement are discussed. A powerful calculation technique based on layered approach is briefly described. A numerical example of application of present method for calculating of stresses, strains and curvatures of reinforced concrete slab is presented.
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Zhu, Zhao, Yuan Li, Shuanhai He, and Chao Ma. "Analysis of the failure mechanism of multi-beam steel–concrete composite bridge under car explosion." Advances in Structural Engineering 23, no. 3 (September 16, 2019): 538–48. http://dx.doi.org/10.1177/1369433219876185.
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The objective of this study is to investigate the damage mechanism of a multi-beam steel–concrete composite bridge under car explosion. The steel–concrete composite bridge is widely used in expressways and urban viaducts. Explosives are distributed in multiple locations above the deck to avoid stress concentration. The explosion damage analysis is carried out with the equivalent trinitrotoluene of 50 kg, which represents a car explosion in the state of full oil tank. The multi-Euler domain method based on the fully coupled Lagrange and Euler models is adopted for the structural analysis of the explosion process with the commercial software Autodyn. This study shows that the structural failure goes through three stages: elastoplastic, plastic, and plastic hinge with full section. From 1/8 to 1/2 of the bridge span, the failure times of the bridge are 277, 164, 133, and 133 ms, matching the displacements of 412, 889, 819, and 819 mm, respectively, while the explosion occurs above steel beams. For the explosion occurring above the concrete deck, the failure times are 335, 154, 121, and 125 ms, corresponding to the deflections of 479, 930, 722, and 752 mm. When the explosion occurs from bearings to the quarter of the bridge span, shear failure of steel beams occurs before bending failure, and both of them control the explosion-resistant design of structures. For the detonation occurring at 1/4 to 1/2 of the bridge length, the explosion damage of the steel–concrete composite bridge is controlled by flexural failure, and only local shear failure occurs. The multi-beam steel–concrete composite bridge which meets the design requirements will generate plastic hinge and lose bearing capacity under car explosion wherever the explosion occurs.
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Chandra, Nurman, Ridwan Ridwan, and Muhammad Ikhsan. "Finite Element Modelling of Reinforced Concrete Beam Strengthened with Embedded Steel Reinforcement Bars." Journal of Applied Materials and Technology 1, no. 1 (August 25, 2019): 38–45. http://dx.doi.org/10.31258/jamt.1.1.38-45.
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The increased of loads on existing reinforced concrete infrastructure and the lack of initial design and construction will induce flexural and shear failure. Several methods have been introduced to increase the shear capacity of existing reinforced concrete elements with FRP, involving the use of plates or fabric externally bonded (EB) to the webs of the bridge beams, prestressed straps wrapped around the beams or bars mounted within grooves prepared in the near-surface mounted (NSM) technique. Typical Indonesian concrete bridges consisted main girders connected with diaphragm beams where the distance between those girders are very close. In particular case, where the webs of the beams are difficult to access, a novel approach is introduced, namely deep embedment (DE) method. Three reinforced concrete beam models are prepared for this study. One specimen is the control specimen and identified, as Beam-CS and the other two are the strengthened specimens and identified as Beam-SS-3EB and Beam-SS-5EB. All specimens have the same dimensions and reinforcement configuration. Specimen Beam-SS-3EB was strengthened with three rows of 6 mm embedded plain steel bars while specimen Beam-SS-5EB was strengthened with five rows of 6 mm plain steel bars. The results showed that element size significantly affects the load-displacement curve behaviour. The similarity of the hysteresis curve in the FE analysis using the 25 mm element size suggested a reasonably good agreement between the analytical calculation and the prediction result from the FE analysis. Furthermore, maximum reaction force for Beam-SS-3EB and Beam-SS-5EB were 30.30 kN and 31.77 kN, respectively, represents an increase of 17.67% and 23.29% compared to that of the Beam-CS.
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Kabanov, Vadim. "Information model for choosing a design solution for providing construction with mortar." E3S Web of Conferences 281 (2021): 04001. http://dx.doi.org/10.1051/e3sconf/202128104001.
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Building materials are usually classified according to the criterion of the possibility of creating a stock at the construction site. Mortars and concrete mixtures have a limited time during which they must be used in the construction of building structures. There are technologies for the use of dry components of mortars from which the mixture is prepared at the construction site. However, the technology of manufacturing mortars at specialized plants is widely used, followed by transportation of the finished cement-sand mixture to the construction site. The problem under consideration raises issues related to the volume of supply of mortars and the intensity of this building material consumption. Within the framework of the research, the tasks of analytical description of the construction and installation work intensity influence on the technological processes of cement-sand mortars delivery to the construction site have been solved, a block diagram of the selection of an economically feasible design solution for providing the production process with a building mixture has been developed. On the basis of the presented results in the form of mathematical dependencies and a block diagram, the conclusions about the influence of a design solution for providing construction with a cement-sand mixture on the duration and construction and installation work cost have been formulated. A graphic representation of the procedure for making a decision on the supply of a construction with a cement-sand mixture is supposed to be used for the development of software that provides a description of the construction processes functioning in space and time, including for 3D models.
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Takallou, H. Barry, Hussain U. Bahia, Dario Perdomo, and Robert Schwartz. "Use of Superpave Technology for Design and Construction of Rubberized Asphalt Mixtures." Transportation Research Record: Journal of the Transportation Research Board 1583, no. 1 (January 1997): 71–81. http://dx.doi.org/10.3141/1583-09.
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The effect of different mixing times and mixing temperatures on the performance of asphalt-rubber binder was evaluated. Four different types of asphalt-rubber binders and neat asphalt were characterized using the Strategic Highway Research Program (SHRP) binder method tests. Subsequently, mix designs were carried out using both the SHRP Levels I and II mix design procedures, as well as the traditional Marshall mix design scheme. Additionally, performance testing was carried out on the mixtures using the Superpave repetitive simple shear test at constant height (RSST-CH) to evaluate the resistance to permanent deformation (rutting) of the rubberized asphalt mixtures. Also, six rectangular beams were subjected to repeated bending in the fatigue tester at different microstrain levels to establish rubberized asphalt mixtures’ resistance to fatigue cracking under repeated loadings. The results indicate that the Superpave mix design produced asphalt-rubber contents that are significantly higher than values used successfully in the field. Marshall-used gyratory compaction could not produce the same densification trends. Superpave mixture analysis testing (Level II) was used successfully for rubberized asphalt mixtures. Results clearly indicated that the mixture selected exhibited acceptable rutting and fatigue behavior for typical new construction and for overlay design. Few problems were encountered in running the Superpave models. The results of the RSST-CH indicate that rubber-modified asphalt concrete meets the criteria for a maximum rut depth of 0.5 in.; and more consistent results were measured for fatigue performance analysis using the repeated four-point bending beam testing (Superpave optional torture testing). The cycles to failure were approximately 26,000 at 600 microstrain.
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Subramani, T., and A. Periasamy. "Study on Behaviour of Stud Type Shear Connector in Composite Beam Using ANSYS." International Journal of Engineering & Technology 7, no. 3.10 (July 15, 2018): 54. http://dx.doi.org/10.14419/ijet.v7i3.10.15629.
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Composite plays a vital role in replacing the existing mild steel in reinforcement and exterior truss structure. This study proposed to design shear connector for joining concrete slab and steel section. Shear connectors has analyzed and predict the best connector for a particular composite beam with respect to static load and the amount of steel in the connector as a common aspect. The use of composite structures is increasingly present in civil construction works nowadays. Composite beams, especially, are structures which include substances, a metal phase placed in particular inside the tension region and a concrete phase, positioned in the compression go sectional location, both are related with the aid of steel gadgets called shear connectors. The main features of this connector are to permit the weight for the joint the beam-column, to restriction longitudinal slipping and uplifting on the factors interface the shear forces. Our project paper presents 3D numerical models of steel-concrete composite beams to simulate their structural behaviour, with emphasis on the beam column interface using Simulations software ANSYS 18.1 based on the Finite Element Method. Mostly these type of structures are widely used in the dynamic loading structures like bridges and high rise buildings.
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Wang, Kun, Zhiyu Zhu, Yang Yang, Kai Yan, Guanpu Xu, and Guanjun Zhang. "Study on shear capacity of prestressed composite joints with concrete-encased CFST columns." Advances in Structural Engineering 24, no. 11 (March 23, 2021): 2457–71. http://dx.doi.org/10.1177/13694332211000558.
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Through assuming reasonable constitutive relation of materials, finite element analysis (FEA) models of joints consisting of prestressed concrete-encased steel beams and concrete-encased concrete filled steel tube (CFST) columns were established by soft ABAQUS, and the simulated results were compared with tested ones. On this basis, the nonlinear analysis on the total loading process was conducted, and the stress variation of concrete, profile steel skeleton, steel bar skeleton, and prestressing tendons were observed at yield, peak, and ultimate loads; the influence of axial compressive ratio, steel tube ratio, stirrup ratio, and prestressing level on lateral load-displacement curves at column top and shear force-shear angle in joint core were investigated, and the shear capacity formulae of joint core were developed. It could be concluded that, the lateral peak loads and shear capacity could be improved with the increase of axial compressive ratio, steel tube ratio, stirrup ratio, and prestressing levels in varying degrees, and the ductility of joints will reduce with the increase of axial compressive ratio. Additionally, the shear capacity calculated by proposed practical formula was a little lower than FEA results, which could keep the joints safety and could be used in engineering design.
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Abdel-Mooty, Mohamed, Medhat Haroun, Yosra El Maghraby, Ezzat Fahmy, and Mohamed Abou Zeid. "Performance of Screen Grid Insulating Concrete Form Walls under Combined In-Plane Vertical and Lateral Loads." Advanced Materials Research 163-167 (December 2010): 1803–10. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.1803.
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Insulating Concrete Forms (ICF) walls generally comprise two layers of Expanded Polystyrene (EPS), steel reinforcement is placed in the center between the two layers and concrete is poured to fill the gap between those two layers. ICF’s have many advantages over traditional methods of wall construction such as reduced construction time, noise reduction, strength enhancement, energy efficiency, and compatibility with any inside or outside surface finish. The focus of this study is the Screen Grid ICF wall system consisting of a number of beams and columns forming a concrete mesh. The performance of ICF wall systems under lateral loads simulating seismic effect is experimentally evaluated in this paper. This work addresses the effect of the different design parameters on the wall behavior under seismic simulated loads. This includes different steel reinforcement ratio, various reinforcement distribution, wall aspect ratios, different openings sizes for windows and doors, as well as different spacing of the grid elements of the screen grid wall. Ten full scale wall specimens were tested where the effects of the various parameters on wall behavior in terms of lateral load capacity, lateral displacement, and modes of failure are presented. The test results are stored to be used for further analysis and calibration of numerical models developed for this study.
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Belostotsky, Alexander M., Pavel A. Akimov, Andrey A. Aul, Dmitry S. Dmitriev, Yulia N. Dyadchenko, Alexander I. Nagibovich, Konstantin I. Ostrovsky, and Andrey S. Pavlov. "Analysis of Mechanical Safety of Stadiums for the World Cup 2018." Scientific journal “ACADEMIA. ARCHITECTURE AND CONSTRUCTION”, no. 3 (September 27, 2018): 118–29. http://dx.doi.org/10.22337/2077-9038-2018-3-118-129.
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It is obvious that contemporary design and construction of unique buildings and structures is unthinkable without mathematical (numerical) and computer modelling and advanced analysis ofload-bearing structures under various kinds ofloads and impacts. One of the most ambitious and important construction projects is the uniquelarge-span structures. These are, in particular, stadiums, sports palaces and water parks, shopping malls, pedestrian, road and railway bridges of various design solutions. The distinctive paper is devoted to theoretical foundations and results of mathematical (numerical) modeling of the state (in terms of the analysis of stress-strain state, strength and stability) of football stadiums built for the 2018 FIFA World Cup in Russia. Finite element method is used for approximation and high-precision numerical solution of corresponding boundary problems of structural mechanics. It is the most universal and powerful numerical method of mechanics. The paper, in particular, describes some features of development of finite element models and the main results of the analysis of the mechanical (structural) safety of three- dimensionallarge-span systems "soil foundation - reinforced concrete structures of foundations and stands - steel structures of the coating and facades" of these football stadiums with the basic and specialload combinations. In addition, the key procedures of scientific support during the corresponding expertise and assessments are outlined. Generally, socially significant and knowledge-intensive problem of providing mechanical (constructive) safety of unique combined objects of construction (three-dimensional systems "foundation - reinforced concrete structures of foundations and stands - steel structures of coating and facades") has been solved at a new level as a result of the performed complex of research works.
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Niyakovski, Alexander M., Uladzimir N. Ramaniuk, Аleksandr N. Chychko, and Yury V. Yatskevich. "Unsteady model of the hydration process of a reinforced concrete product at software-controlled heating." Doklady of the National Academy of Sciences of Belarus 63, no. 4 (September 13, 2019): 496–505. http://dx.doi.org/10.29235/1561-8323-2019-63-4-496-505.
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The development of mathematical models for design of the thermal technology equipment intended for accelerated hydration of concrete products is an urgent task of industrial heat power engineering. The introduction of mathematical modeling methods can reduce the time and the resources spent for the development of technological regimes that reduce energy consumption in the production of building structures and, ultimately, in the construction of buildings and structures for various purposes. There is not yet a generally accepted mathematical model of thermal processes occurring in thermal technological installations in the case of accelerated hardening of a three-dimensional concrete object. The purpose of this work is to develop an unsteady model of the concrete hydration process applied to a symmetrical three-dimensional reinforced concrete product at software-controlled heating. By using the numerical finite-volume method in the case of a 0.3 × 0.3 ×0.3 mcube, a three-dimensional feld of hydration in a concrete object at a given operation mode of a heater is calculated. The following heating mode was used: “heating–maintaining at a constant temperature–cooling”. The dependences of a temperature difference between reinforced and non-reinforced cubic products on the hardening time at the corresponding space points in the direction from the surface to the center of the product have been obtained. By the example of the numerical simulation results, it is shown that the evolution of the hydration degree at these points during the hardening of non-reinforced concrete differs from the hardening of reinforced concrete. The time dependences of heat treatment of a rate of temperature change and the hydration coefficient at the selected points of a product are presented. The obtained results are analyzed.
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Wu, Liao, Zhihua Chen, and Bin Rong. "Calculation method for the shear bearing capacity of diaphragm-through connections." Advances in Structural Engineering 20, no. 6 (November 11, 2016): 906–16. http://dx.doi.org/10.1177/1369433216666444.
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This article presents the results of experimental, numerical, and theoretical studies into the shear behavior of panel zone of diaphragm-through connections between concrete-filled square steel tubular columns and steel beams. The current design code does not cover the yield and ultimate shear strengths of such connections in China. Five tee-shaped diaphragm-through connections were fabricated and tested that they comply with the principle of “strong members and weak panel zone.” Three-dimensional nonlinear finite element models were developed to study the shear behavior of the panel zone under low-frequency cyclic loading. Based on the test results, the force transfer mechanism and the effect of different factors on the panel zone shear capacity were analyzed. The width and deformation of compression strut of core concrete were taken into account. A simple manual calculation method was also proposed for evaluating the shear strength of panel zone of diaphragm-through connections. Good agreement was found between theoretical and test results for both yield and ultimate shear strengths for connections.
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Sukrawa, Made, Gede Pringgana, and Putu Ayu Ratih Yustinaputri. "Modelling of confined masonry structure and its application for the design of multi-story building." MATEC Web of Conferences 276 (2019): 01034. http://dx.doi.org/10.1051/matecconf/201927601034.
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The confined masonry (CM) structure has been commonly used in the construction of one-story buildings in Indonesia. Its application for multi-story buildings however, is not yet as popular as the alternative options. This research numerically investigated the behavior of confined masonry and its application for use as the main structure of multi-story buildings subjected to seismic loading. From the validation models it was revealed that, using shell element for masonry walls, reinforced concrete beams and tie-columns, the CM model mimic the load deformation curve of tested specimen better than that using frame and shell elements. The application of the modeling technique for the design of 3-story residential building using wall density index less than that suggested in the literature resulted in a safe and stiff structure. The wall stresses under design seismic load were still less than the wall strength and the drift ratio of the model was 0.06% much smaller than the limit of 0.2%. The maximum stress observed at the corners of wall opening justify the need for confinement along the opening.
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Vu Dinh Tho and Elena A. Korol. "Influence of contact layers on cracking resistance of bending three-layer structures." Vestnik MGSU, no. 7 (July 2020): 988–98. http://dx.doi.org/10.22227/1997-0935.2020.7.988-998.
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Introduction. In the present-day construction practice, multilayer building envelopes are applied; their layers are made of concretes having different physical and mechanical characteristics. When different concretes are poured in successive layers, contact layers are formed; their physical and mechanical properties are unlike those of the adjacent layers. The strength and stress-strain characteristics of the contact layers can affect the behaviour of a multilayer structure.
Materials and methods. Numerical and experimental methods are applied to study the stress-train state of such structures exposed to loading. Bending three-layer structural models, having external layers made of strong structural concrete and the middle layer made of low-strength concrete, were applied in the research project. A contact layer is formed in the process of their manufacturing; its geometrical, strength and stress-strain characteristics are simulated in the process of numerical studies.
Results. The co-authors have identified the effects produced by geometrical, strength and stress-strain characteristics of contact layers on the analysis of bending multilayer structures. Design models and a novel method of analysis have been developed for bending multilayer reinforced concrete structures with account taken of the influence of geometrical, strength and stress-strain characteristics of the contact layer. According to the results of numerical calculations, differences between cracking moments can reach 4.3 % or more for three-layer reinforced concrete beams. As for the practical calculations, if the thickness of the contact layer is below 0.4 cm, one can ignore the influence produced by the contact layer on the calculation result.
Conclusions. The results of the research help to identify the rational parameters for the design of multilayer enclosing structures having varying strength reinforced concrete layers interconnected by the monolithic contact layer.
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Marx, Hendrig, and Richard Walls. "Thermal behaviour of a novel non-composite cellular beam floor system in fire." Journal of Structural Fire Engineering 10, no. 3 (September 9, 2019): 354–72. http://dx.doi.org/10.1108/jsfe-10-2018-0032.
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Purpose The Southern African Institute of Steel Construction has developed a novel cellular beam structure (CBS) for multi-storey buildings that is entirely devoid of concrete. Channel sections between the cellular beams support a complex sandwich flooring system, which contains a fire-resistant ceiling board, metal sheeting, an interior fibre-cement board and an access-flooring system. As for all structures, the CBS requires a fire rating. This paper aims to investigate the thermal behaviour of the CBS using numerical modelling and experimental fire testing, as it has a unique setup. Design/methodology/approach Experimental fire tests on the flooring system were conducted to validate finite element models, which were developed in ABAQUS. These models were then extended to include floor beams and the structural steelwork. Findings Good correlations were found between the experimental and numerical results, with temperature variations typically in the range of 0-5%, although with localised differences of up to 20%. This allowed larger finite element models, representing the sandwich floor system of the CBS, to be developed and analysed. A 1-hour rating can be obtained by the system in terms of insulation and integrity requirements. Practical implications The CBS allows for more economical steel structures, due to the rapid construction of its modular panels. A suitable fire resistance will ensure the safety of the occupants and prevent major structural damage. Steelwork and flooring temperatures are determined which has allowed for global structural analyses to be carried out. Originality/value The originality of this study lies in thermal analysis and testing of a new cellular beam flooring system, through determining behaviour in fire, along with beam temperatures.
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Mohamed, Osama Ahmed, Waddah Al Hawat, and Mohammad Keshawarz. "Durability and Mechanical Properties of Concrete Reinforced with Basalt Fiber-Reinforced Polymer (BFRP) Bars: Towards Sustainable Infrastructure." Polymers 13, no. 9 (April 26, 2021): 1402. http://dx.doi.org/10.3390/polym13091402.
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Reducing the fingerprint of infrastructure has become and is likely to continue to be at the forefront of stakeholders’ interests, including engineers and researchers. It necessary that future buildings produce minimal environmental impact during construction and remain durable for as long as practicably possible. The use of basalt fiber-reinforced polymer (BFRP) bars as a replacement for carbon steel is reviewed in this article by examining the literature from the past two decades with an emphasis on flexural strength, serviceability, and durability. The provisions of selected design and construction guides for flexural members are presented, compared, and discussed. The bond of BFRP bars to the surrounding concrete was reportedly superior to carbon steel when BFRP was helically wrapped and sand coated. Experimental studies confirmed that a bond coefficient kb = 0.8, which is superior to carbon steel, may be assumed for sand-coated BFRP ribbed bars that are helically wrapped, as opposed to the conservative value of 1.4 suggested by ACI440.1R-15. Code-based models overestimate the cracking load for BFRP-reinforced beams, but they underestimate the ultimate load. Exposure to an alkaline environment at temperatures as high as 60 °C caused a limited reduction in bond strength of BFRP. The durability of BFRP bars is influenced by the type of resin and sizing used to produce the bars.
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Su, Jizhi, Boquan Liu, Guohua Xing, Yudong Ma, and Jiao Huang. "Influence of Beam-to-Column Linear Stiffness Ratio on Failure Mechanism of Reinforced Concrete Moment-Resisting Frame Structures." Advances in Civil Engineering 2020 (January 10, 2020): 1–24. http://dx.doi.org/10.1155/2020/9216798.
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The design philosophy of a strong-column weak-beam (SCWB), commonly used in seismic design codes for reinforced concrete (RC) moment-resisting frame structures, permits plastic deformation in beams while keeping columns elastic. SCWB frames are designed according to beam-to-column flexural capacity ratio requirements in order to ensure the beam-hinge mechanism during large earthquakes and without considering the influence of the beam-to-column stiffness ratio on the failure modes of global structures. The beam-to-column linear stiffness ratio is a comprehensive indicator of flexural stiffness, story height, and span. This study proposes limit values for different aseismic grades based on a governing equation deduced from the perspective of member ductility. The mathematical expression shows that the structural yielding mechanism strongly depends on parameters such as material strength, section size, reinforcement ratio, and axial compression ratio. The beam-hinge mechanism can be achieved if the actual beam-to-column linear stiffness ratio is smaller than the recommended limit values. Two 1/3-scale models of 3-bay, 3-story RC frames were constructed and tested under low reversed cyclic loading to verify the theoretical analysis and investigate the influence of the beam-to-column linear stiffness ratio on the structural failure patterns. A series of nonlinear dynamic analyses were conducted on the numerical models, both nonconforming and conforming to the beam-to-column linear stiffness ratio limit values. The test results indicated that seismic damage tends to occur at the columns in structures with larger beam-to-column linear stiffness ratios, which inhibits the energy dissipation. The dynamic analysis suggests that considering the beam-to-column linear stiffness ratio during the design of structures leads to a transition from a column-hinge mechanism to a beam-hinge mechanism.
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Bouzid, Leyla, Mohand Hamizi, Naceur-Eddine Hannachi, Aghiles Nekmouche, and Karim Akkouche. "Plastic hinges mechano-reliability analysis in the beams of RC frames structures." World Journal of Engineering 17, no. 5 (August 4, 2020): 719–32. http://dx.doi.org/10.1108/wje-02-2020-0069.
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Purpose The purpose of this study is to establish a relationship between causes and effects, the respect of materials characteristics values [concrete compressive strength (fc) and steel yield stress (fy)] and the norms of the construction dispositions value (covers). This study is motivated by the post-seismic damages related to the plastification of the reinforced concrete (RC)/beams sections, named plastic hinges. The results are given by fragility curves representing the failure probability (Pf) of the plastic hinges versus covers value. Design/methodology/approach A mechanical-reliability coupling methodology is proposed and performed on three frames (three, six and nine storey). For each frame, seven covers the value of reinforcement steel bars has been taken into account in the beams. After definition of the limit state function G(x), a process of idea to twin-track; deterministic and probabilistic, is considered. Thus, numerical simulations are carried out under ETABS© software, to extract a soliciting moments Ms(x). Then, ultimate moments Mu(x), the result of reliability approach are calculated using Monte Carlo Simulations. In this step, two random variables; concrete compressive strength in 28 days of age (fc) and steel yield stress (fy), have been studied. Findings In the mechanical study, the results show that, the first plastic hinge appears at the beams for all frames. In the reliability study, the (fy) variation shows that all plastic hinges are in failure domain, nevertheless, the (fc) variation leads to have all sections in the safety domain, except A7 and B7 models. The failure probability (Pf) calculation according to (fc) and (fy) shows that an absolute error of 0.5 cm in the steel bars covers can switch the frame from the safety domain to the failure domain. Originality/value The plastic hinges reliability of the RC/ frame structures is independent on the high of the structure. The (fc) random variable according to the used distribution law does not affect the reliability (safety or failure). However, the impact of the steel yield stress variation (fy) is not negligible. The errors in covers affect considerably the strength of the elements.
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Pan, Jianwu, Xian Wang, and Fang Wu. "Strengthening of Precast RC Frame to Mitigate Progressive Collapse by Externally Bonded CFRP Sheets Anchored with HFRP Anchors." Advances in Civil Engineering 2018 (December 27, 2018): 1–11. http://dx.doi.org/10.1155/2018/8098242.
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Currently, the robustness of precast reinforced concrete frames is attracting wide attention. However, avoiding “strong beams and weak columns” during strengthening against progressive collapse is a key problem. To discuss this problem, an experimental study on two 1/2-scale precast frame subassemblages under a pushdown loading regime was carried out in this paper. One specimen was strengthened with carbon fibre-reinforced polymer (CFRP) sheets on the beam sides. The middle parts of the CFRP sheets were anchored with hybrid fibre-reinforced polymer (HFRP) anchors. Another specimen was not strengthened. The failure mechanisms, failure modes, and strengthening effect are discussed. The strengthening effect is very obvious in the early catenary action stage. No shearing failure develops on HFRP anchors, which proves that the anchoring method is effective. Based on the experimental results, analytical models and preventive strengthening design and construction measures to mitigate progressive collapse of the precast RC frame are proposed.
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Mahamid, Ibrahim. "Preliminary estimate for reinforcement steel quantity in residential buildings." Organization, Technology and Management in Construction: an International Journal 8, no. 1 (December 1, 2016): 1405–10. http://dx.doi.org/10.1515/otmcj-2016-0006.
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Abstract The objective of this study was to develop prediction mathematical equations to compute reinforcement steel quantity in traditional residential buildings based on 158 sets of data collected in the West Bank in Palestine. The records related to the quantities were collected from consultancy firms that provide reinforced concrete design services. The data were collected for residential buildings up to four floors. Linear regression analysis was chosen to show the correlation between the included variables. The following variables were used in the regression models: quantity of reinforcement steel (dependent variable), structural element volume (independent variable) and floor area (independent variable). Fourteen models were developed; nine models were developed to compute the quantity of reinforcement steel in different structural elements: slabs, beams, columns and footings. The other five models were used to estimate the total steel quantity in a residential building. The coefficient of multiple determination (R2) of the developed models ranged from 0.70 to 0.82. This confirms a good correlation between the dependent and the independent variables. The accuracy of the developed models was tested using the mean absolute percentage error (MAPE) test. With MAPE values ranging from 21% to 36%, the results compare favourably with past research that indicated that accuracy between ±25% and ±50% at the early stages is acceptable. The results also show that the models built on structural element size have better accuracy than the models using floor area. Such types of equations are very useful, especially in their simplicity and ability to be handled by calculators or simple computer programmes.
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Fagen, M. E., and B. M. Phares. "Life-Cycle Cost Analysis of a Low-Volume Road Bridge Alternative." Transportation Research Record: Journal of the Transportation Research Board 1696, no. 1 (January 2000): 8–13. http://dx.doi.org/10.3141/1696-37.
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Life-cycle cost models offer engineers a means to evaluate the anticipated long-term economic performance of prospective design and construction alternatives. Traditionally, only initial investment costs and past experience were used to economically evaluate possible bridge designs. A more logical approach requires that all short- and long-term costs be considered in relation to project location, purpose, and performance specifications. The primary objective of life-cycle cost analysis is to evaluate the total ownership cost of all suitable alternatives. Recent reports indicate that a significant number of the nation’s bridges are either structurally deficient or functionally obsolete. In Iowa, a large portion of these types of bridges are on the secondary road system and fall under the jurisdiction of county engineers. Typically, Iowa county engineers have limited resources. In response to this, a bridge-replacement system was developed that county engineers can design and build with limited staff. The system, which is made up of precast (PC) double T units, involves the fabrication of PC units that consist of two steel beams connected by a thin concrete deck. To illustrate that this bridge system may be an economically viable bridge-replacement alternative for use on low-volume county roads, a life-cycle cost analysis was completed for an actual replacement-repair-rehabilitation project. Various alternatives were economically analyzed and compared with the steel beam PC unit bridge alternative. This analysis indicates that, when lower-cost salvaged steel beams and county work forces are used, the steel beam PC unit bridge can be a viable low-volume road bridge alternative.
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Zahedinejad, Parham, Chen Zhang, Haifeng Zhang, and Shuai Ju. "A Comprehensive Review on Vibration Analysis of Functionally Graded Beams." International Journal of Structural Stability and Dynamics 20, no. 04 (April 2020): 2030002. http://dx.doi.org/10.1142/s0219455420300025.
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Beams and beam structures are structural components commonly used in mechanical, aerospace, nuclear, and civil engineering. To meet the different engineering design limitations such as operational conditions, weight, and vibrational characteristics, these components may be made of various materials such as functionally-graded materials (FGMs), composites, and homogeneous materials. Functionally-graded (FG) beams play a key role not only in classical structural applications, but also have vast applications in thermal, electric-structural and electric-thermal-structural systems, e.g. in the form of FG beam energy harvesters, sensors and actuators. In all these applications, using new materials like FGMs can greatly improve the efficiency of the structural components and systems. Since FG beams are mostly used as moving components in engineering structures, vibration analysis of these components has been studied by numerous researchers. In order to solve the governing equation and related boundary conditions of the FG beams, powerful numerical methods with a high level of accuracy and fast rate of convergence are often required. The differential quadrature method (DQM) is a powerful and reliable numerical method which has been extensively used by researchers to perform the vibration analyses of FG structures in the last decade. In this paper, firstly various mathematical models which have been used to express the material properties of FGMs are reviewed. Secondly different elasticity theories which have been applied in vibration analysis of FG beams are summarized. In addition, a review on the DQM and its applications is presented. At the next step, a comprehensive review on free vibration analyses of FG beams based on different elasticity theories and in particular those using the DQM is performed. In continue, a brief review on the application of other numerical methods in vibration analysis of FG beams is presented. Moreover, because of the importance of nonlinear vibration analysis of FG beams, a review on the application of various numerical methods and different elasticity theories on nonlinear vibration analysis of FG beams is performed. Finally, a brief review on linear and nonlinear vibration analysis of FG microbeams, as a special type of FG beams, is presented.
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Денисова, Е., E. Denisova, Тимур Хуснетдинов, Timur Husnetdinov, Марианна Воронина, and Marianna Voronina. "Projection by Conical Helical Lines With Constant Pitch." Geometry & Graphics 6, no. 3 (November 14, 2018): 13–19. http://dx.doi.org/10.12737/article_5bc4563ccf6884.11983902.
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This paper’s purpose is investigation of non-traditional projection systems and their projecting surfaces, the choice of such congruence parameters for conical helical lines, which allow cover the whole complex of requirements to the surface, obtained by projecting of an arbitrary flat or spatial line with congruence beams, as well as the use of computer graphics in surface visualization. In the paper has been presented an example of analytical interpretation for an image of curvilinear projection by conical helical lines with constant pitch, and a congruence example for conical helical lines located on coaxial cones with a common vertex and a variable angle of generatrix inclination to an axis. Have been investigated properties and defined parameters of the congruence helical line passing through a space arbitrary point which is not belonging to an axis. An approach for construction of spiral surfaces, which frame consists of beams projecting an arbitrary line. A form generation of surfaces by analytical methods and their visualization by means of computer graphics is one of applied geometry’s urgent problems in connection with the use of such methods in automated systems for scientific research, design, and manufacture on equipment with computer numerical control. The leading research method for this problem is the general analytical theory for surfaces’ applied form generation developed by Professor I.A. Skidan and formed a unique apparatus, based on mathematical support of computing technologies for design and creation of objects with complex forms. On examples of visualization for projecting surfaces by means of computer graphics it is possible to show applicability of analytical models in computer technologies for scientific researches, design and manufacturing.
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Mourlas, Christos, Neo Khabele, Hussein A. Bark, Dimitris Karamitros, Francesca Taddei, George Markou, and Manolis Papadrakakis. "Effect of Soil–Structure Interaction on Nonlinear Dynamic Response of Reinforced Concrete Structures." International Journal of Structural Stability and Dynamics 20, no. 13 (October 14, 2020): 2041013. http://dx.doi.org/10.1142/s0219455420410138.
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Investigating the nonlinear dynamic response of reinforced concrete (RC) structures is of significant importance in understanding the expected behavior of these structures under dynamic loading. This becomes more crucial during the design of new or the assessment of the existing RC structures that are located in seismically active areas. The numerical simulation of this problem through the use of detailed 3D modeling is still a subject that has not been investigated thoroughly due to the significant challenges related to numerical instabilities and excessive computational demand, especially when the soil–structure interaction (SSI) phenomenon is accounted for. This study aims at presenting a nonlinear simulation tool to investigate this numerically cumbersome problem in order to provide further inside into the SSI effect on RC structures under nonlinear dynamic loading conditions. A detailed 3D numerical model of full-scale RC structures considering the SSI effect through modeling the nonlinear frame and soil domain is performed and discussed herein. The constructed models are subjected to dynamic loading conditions and an elaborate investigation is presented considering different type of structures, material properties of soil domains and depths. The RC structures and the soil domains are modeled through 8-noded hexahedral isoparametric elements, where the steel bar reinforcement of concrete is modeled as embedded beam and truss finite elements. The Ramberg–Osgood constitutive law was used for modeling the soil domain. It was shown that the SSI effect can significantly increase the flexibility of the system, altering the nonlinear dynamic response of the RC frames causing local damages that are not observed when the fixed-base model is analyzed. Furthermore, it was found that the structures founded on soft soil developed larger base-shear compared to the fixed-base model which is attributed to resonance phenomena connected to the SSI effect and the imposed accelerograms.
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Codina, Ramon, and Daniel Ambrosini. "Numerical and analytical study of overpressures and impulses inside a masonry box subjected to external blast loading." International Journal of Protective Structures 10, no. 3 (April 24, 2019): 270–88. http://dx.doi.org/10.1177/2041419619843636.
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Blast loads have attracted considerable attention in recent years due to accidental or intentional events involving important structures, which have occurred around the world. The activities related to terrorist attacks have increased and, unfortunately, the current trend suggests that they will continue to rise in the future. In relation to the design of structures subjected to blast loadings, there are still many uncertainties in the specialized technical literature. Particularly, the overpressures and impulses inside constructions are difficult to estimate due to many reflections of the shock wave. The main objective of this work is to study the propagation of the blast wave inside constructions subjected to external loadings. An experimental study was performed using a masonry box with reinforced concrete beams and columns and a typical window. The results were previously presented. In this article, numerical models are developed in order to compare results and to obtain design guidelines. Explosive charges of equivalent 1–5 kg of TNT and elevated 1 m above the ground were detonated at different distances from the window, and overpressures and impulses were obtained at five points inside and outside the room. However, empirical–analytical results using a well-known technical manual are also obtained and compared. The obtained results are useful to evaluate numerical codes and empirical formulas.