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1
R., H. Mohankar*, Imran Alam Md., Gaurav Gopesh, and Choudhary Shubham. "A STUDY OF PORTAL FRAME USING ANALYTICAL METHODS AND ETABS SOFTWARE." INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY 5, no. 3 (2016): 835–40. https://doi.org/10.5281/zenodo.48372.
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Analysis of portal frames involves lot of complications and tedious calculations by conventional methods. To carry out such analysis is a time consuming task. The Moment Distribution Method & Slope Deflection Method for analysis of portal frames can be handy in approximate and quick analysis so as to get the detailed estimates ready. In this work, these two methods have been applied only for vertical loading conditions. This paper mainly deals with the comparative analysis of the results obtained from the analysis of single bay portal frame when analyzed manually and using ETABS Software separately. The result obtained from manually is mostly matched with the results obtained from ETABS software.
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Chen, Xu, and Hui Min Li. "The Alculation Method of Stable Bearing Capacity of Portal Frame." Applied Mechanics and Materials 351-352 (August 2013): 329–36. http://dx.doi.org/10.4028/www.scientific.net/amm.351-352.329.
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In recent years, the portal frame structure in the actual project has been widely used, but using the finite element method calculation of stable bearing capacity of portal frame is more complex, and very difficult to the design and construction personnel. With the known stability of the cantilever column carrying capacity and the vertex of the lateral displacement under concentrated force, the establishment of the ratio of the portal frame stability capacity and the stability of the cantilever column carrying capacity both in the same concentrated force vertex lateral displacement than the relationship between the structural mechanics solver to seek out frame to the lateral displacement of the vertex under concentrated force, obtained by computing the stability capacity of the portal frame, and with the exact solution comparison and found that the methods of theoretical calculation results coincide with the exact solution, and then get an easy way of solving the portal frame stable bearing capacity. After numerical example, this method is simple, easy to master, and it has important reference value.
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Faridmehr, Iman, Mahmood Md Tahir, Tom Lahmer, and Mohd Hanim Osman. "Seismic Performance of Steel Frames with Semirigid Connections." Journal of Engineering 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/5284247.
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The nonlinear stiffness matrix method was incorporated to investigate the structural performance of steel portal frames with semirigid connections. A portal frame with unstiffened extended end-plate connection was designed to demonstrate the adequacy of the proposed method. Besides, the seismic performance of steel portal frames with semirigid connections was investigated through time history analysis where kinematic hysteresis model was assigned to semirigid connections to account for energy dissipation and unloading stiffness. Based on the results of the study, it was found that generally semirigid connections influenced the force distribution which resulted in the decrease in base shear and lighter frame compared to the rigid one. The results also indicated that there was no direct relationship between maximum displacement at the top and connection stiffness in high-rise frames.
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BASAGA, H. B., M. E. KARTAL, and A. BAYRAKTAR. "RELIABILITY ANALYSIS OF STEEL BRACED REINFORCED CONCRETE FRAMES WITH SEMI-RIGID CONNECTIONS." International Journal of Structural Stability and Dynamics 12, no. 05 (2012): 1250037. http://dx.doi.org/10.1142/s021945541250037x.
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This paper presents the reliability analysis of the frame structures with semi-rigid connections. For this purpose, the SEMIFEM finite element program that is capable of dealing with the semi-rigid connections is coded in FORTRAN. Then, this program is connected to the reliability algorithm. The direct coupling method, which is a combination of the reliability method and finite element method, is utilized to determine the reliability indexes and probabilities of failure for the structure. The first order reliability method (FORM) is the one favored in the present reliability analysis. Two sets of steel framed structures are analyzed; each of four and eight stories, consisting of a portal frame and three types of concentrically braced frames. Concrete compression strength limit state in reinforced concrete (RC) columns, steel strength limit state in steel braces and inter-story drift limit state are considered in reliability evaluation. According to the limit states, X braced frames are determined as the safest structures, while the portal frames are regarded as the most unsafe structures. As the connection percentage increases, the safety of the structure increases in terms of inter-story drift and steel strength limit states, but decreases for concrete compression strength limit states.
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Far, Harry, and Claire Far. "Timber Portal Frames vs Timber Truss-Based Systems for Residential Buildings." Advances in Civil Engineering 2019 (July 28, 2019): 1–7. http://dx.doi.org/10.1155/2019/9047679.
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A large number of structures have been built during or after the construction of a house or residential-zoned building, which are not built at the same time and/or integrally with the structural integrity of the residential dwelling. These include carports, pergolas, sheds, and barns. The typical method of constructing these structures is a general timber truss and column system. The aim of this study is to look at the feasibility and economic incentive that may be gained from using a timber portal frame system, similar to the steel or timber portal frames used for larger industrial constructions, over the traditional timber truss and column arrangement. In this study, designs for three cases of timber truss and timber portals were carried out using industry appropriate methods and standards. Using the design information and data gathered through talks with industry professionals, both methods of construction were compared on cost and overall time duration. From the comparison of the truss and portal designs, the use of timber portal frames over timber truss systems proved to have advantage in relation to overall cost and man power involved. This could certainly affect the current attitude towards the construction of small residential buildings in the future.
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Liu, Feng, and Xiao Yan Wang. "Overall Reliability Assessment of Portal Frame Structure with Roof Beam Outward Offset." Applied Mechanics and Materials 501-504 (January 2014): 628–33. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.628.
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This article deals with the condition that the roof beams of portal frame are outward offset beyond the standard limit, determines the most unfavorable position of the portal frame structure under the load and establishes the criterion standard of structural failure based on the space overall finite element analysis. It adopts Monte-Carlo method in reliability analysis methods to realize the overall reliability analysis of the portal frame structure with the roof beam outward offset. Analysis shows that the actual structure is at safe state under the design load and the reliability conforms to the standard requirement.
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Xie, Ming, Fangbo Xu, Zhangdong Wang, et al. "Investigating Fire Collapse Early Warning Systems for Portal Frames." Buildings 15, no. 2 (2025): 296. https://doi.org/10.3390/buildings15020296.
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In recent years, firefighter accidents and people injured by the collapse of steel structures during a fire have occurred frequently, which has attracted the attention of the National Emergency Management Department and the Fire and Rescue Bureau. It is urgent to carry out research on early warning systems for building collapse during a fire. Existing early warning methods mainly use characteristic parameters such as temperature, vibration, and structural deformation. Due to the complexity of an actual fire, it is difficult to accurately predict the critical temperature of fire−induced instability in columns and the failure mode after the instability, and there are deviations in the collapse warnings. In this study, changes in ultrasonic transverse and longitudinal wave velocities at high temperatures are used to monitor the stiffness degradation of columns in fire in real time and improve the accuracy of early warning systems. In this study, four common collapse modes of portal frames are obtained by using the results of parametric numerical analysis. According to key displacements and the displacement rates of simple key measuring points, the elastic modulus threshold of a three−level early warning for portal frame collapse with different collapse modes is obtained. Combined with an ultrasonic experiment, the theoretical relationships between the transverse and longitudinal wave velocities and the elastic modulus of steel at high temperatures are verified, and the relationship between the transverse and longitudinal wave velocities and the overall damage of the portal frame is further constructed; then, a new early warning method for portal frame stability during a fire is proposed. Based on the change in wave velocity, a three-level early warning index for predicting portal frame stability during a fire is determined. When the collapse mode of a portal frame is an overall inward collapse, transverse and longitudinal wave velocities are reduced to 2635 m/s and 5308 m/s, respectively. At a second-level warning, they are reduced to 2035 m/s and 4176 m/s, respectively. At 1504 m/s and 3030 m/s, respectively, third-level warnings are issued. This research shows that the real−time monitoring of wave velocities provides an effective way for early warning systems to identify structural collapse. The proposed early warning method can be used as a quick and efficient early warning system for the collapse of portal frames during a fire, and its accuracy and applicability are verified by experiments.
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Jia, Wen Wen, and Deng Feng Wang. "Internal Force Evaluation of Non-Uniform Beam in Portal Frame." Applied Mechanics and Materials 423-426 (September 2013): 1454–58. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.1454.
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To simplify the internal force evaluation of portal frame being composed of non-uniform members, the force method was used to solve internal force of every key section of the non-uniform beam in portal frame with single-span. Gauss numerical integration method was used to simplify the complex integration when the deformation energy was calculated. Under the precondition of satisfied accuracy, the direct expressions of bending momentshear force and axial force of every key section of beam were obtained. The research work can be used as reference for the evaluation and design of portal frame members.
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Sabbagh-Yazdi, Saeed-Reza, and Ainullah Mirzazadah. "Comparing Numerical Results for Seismic Performance of Portal Steel Frames Braced with Steel: HSS Brace, Glulam Timber Brace, and Timber-Steel-BRB." Advances in Civil Engineering 2022 (July 20, 2022): 1–17. http://dx.doi.org/10.1155/2022/2705691.
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This study involves the application of timber-based bracings elements. For this purpose, seismic analyses are performed on special portal steel frames without the brace and diagonally braced with Glued Laminated Timber (glulam) and Timber-Steel Buckling Restrained Brace (TS-BRB), and the results are compared with the same configuration using steel Hollow Structural Sections (HSS) bracing, using OpenSees structural analyzer. First, to verify the accuracy of the modeling, the numerical results are compared with experimental measurements on several types of elements: (a) diagonally braced frame with steel Hollow Structural Sections with a concentrically steel braced frame which was tested by the quasi-static method under cyclic loading protocol by previous researchers, (b) diagonally glulam braced frame with results of shake table tests on single-story timber braced frames, and (c) Timber-Steel Buckling Restrained Brace (TS-BRB) frame with experimental results of Heavy Timber Buckling-Restrained Braced Frame (HT-BRB). In the second step, the aforementioned timber base bracing alternatives (glulam, TS-BRB) are applied in the special portal steel frame, then the seismic performance of the frame is investigated under pushover, cyclic, time history, and incremental dynamic analysis (IDA), and then the results are compared with the behavior of similar portal frame in two conditions without the brace and diagonally braced with the steel-HSS brace. Results showed that steel-HSS, glulam, and timber-steel buckling restrained braces have significant roles in energy dissipation, increasing shear capacity, decreasing interstory drift, and decreasing weight and cost of estimation of the structure.
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S. J. Modak, S. J. Modak. "Determination of Influence Lines of a Portal Frame Adopting Matrix Method of Structural Analysis." Indian Journal of Applied Research 3, no. 7 (2011): 224–26. http://dx.doi.org/10.15373/2249555x/july2013/70.
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Dadra, Sarpreet, Jatinder Kumar, Satinderjit Singh, et al. "Investigation on the influence of point loads on the deflection behaviour of G+5 frame structure." IOP Conference Series: Earth and Environmental Science 889, no. 1 (2021): 012017. http://dx.doi.org/10.1088/1755-1315/889/1/012017.
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Abstract Nowadays, multi-storey structure portal frames are most commonly used worldwide. Multistory frames are used in structural systems in all metropolitan cities, future cities, and important businesses. The present study the effect of various point loads varying from 22 to 32 kN in steps of 2 were applied on the center of horizontal beams of the frame structure. The deflection behaviour in form of deflection, reaction, beading moments under point loading were discussed analytically according to stiffness matrix method and the results are validated with the help of simulation using STAAD Pro software. Results revealed that the analytical method using manual calculations in excel sheet provides approximately similar results as obtained by the costly simulation technique using STAAD Pro software. Therefore, the implementation of this excel sheet can be recommended for standard analysis of portal frame structures based on the outcomes of this study.
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Lin, Xian Gen, and Yong Xu. "The Comparison of Portal Frame Design by Penalty Function Optimization and Traditional Method." Advanced Materials Research 452-453 (January 2012): 348–53. http://dx.doi.org/10.4028/www.scientific.net/amr.452-453.348.
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The comparison of portal frame design by penalty function optimization and traditional method aim at 30m span portal frame with tapered members was made. It was found that the essence of optimization design was to research the reasonable distributing of sections, through the interaction between capacity and key section parameters the optimization design were realized. Now the idea of green and less energy is fashionable, then optimization design is very significant in practical engineering. According to engineering statistics the optimization design can reduce 15%~30% of material quantity. In this article the selection of parameters during optimization design was expounded.
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Abimbola, Yusuf Zainab, Jibrin Mohammed Kaura, and Uwemedimo Nyong Wilson. "Reliability-Based Analysis of Steel Portal Frame Eurocode Design Criteria Subjected to Flexural and Lateral Torsional Instability." Saudi Journal of Civil Engineering 9, no. 02 (2025): 37–48. https://doi.org/10.36348/sjce.2025.v09i02.002.
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Steel portal frames, used in factories, workshops, shopping complexes, and warehouses, provide large clear spans. Eurocode 3, a semi-probabilistic design code based on limit state design and adopted in Nigeria, does not fully address uncertainties in load and resistance variables, affecting frame performance in service. This study evaluates the reliability of three-hinged steel portal frames by analyzing three primary failure modes: flexural instability of frame stanchions (failure mode 1), flexural instability of frame rafters (failure mode 2), and lateral torsional instability of stanchions and rafters (failure mode 3). Limit state functions for these failure modes were derived from Eurocode 3 specifications and structural analysis load effects. Stochastic models of uncertain parameters are obtained from the literature. The First-Order Reliability Method (FORM), using a MATLAB program, evaluates the limit state functions and determines failure probability. Results show that for failure mode 1, Eurocode's target reliability of 3.8 is met if Xc is at least 0.85 for stanchions and 0.6 for rafters. At flexural buckling (XLT = 1.0), lateral-torsional stability yields a safety index of 5.8. For failure modes 1 and 2, the safety index decreases with a higher dead load to variable load ratio. For all failure modes, the safety index increases with higher steel grades and coefficient of variation (CoV). To ensure safety, the study recommends fully accounting for uncertainties in design to prevent up to a 60% compromise in portal frame safety.
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Apriani, Widya, Anggi Barus, and Fadrizal Lubis. "Uji Eksperimental Respon Struktur 3D Modelling Struktur Portal Open Frame dan Struktur Portal Bresing terhadap Beban Gempa." Journal of Infrastructure and Civil Engineering 1, no. 1 (2021): 1–12. http://dx.doi.org/10.35583/jice.v1i1.1.
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One of the obstacles in laboratory testing is the availability of testing capacity. So that the similitude method was developed which aims to replicate the state of the prototype by scaling the variables so that they can be tested in the laboratory. The purpose of this study was to determine the difference between the results of numerical tests and experimental tests on the response of the open frame portal structure and the braced portal structure to the perpindahan parameters and the driftt ratio of the steel portal structure in earthquake buildings. The method used in this research is the experimental test method. From the analysis results, the largest perpindahan difference between the numerical test and the experimental test of the open frame portal structure is on the 4th floor, with a difference of 21,8 mm, while the largest perpindahan difference in the braced structure is on the 6th floor with a difference of 14,54 mm. The highest perpindahan difference is between numerical tests and experimental tests that occur on the open frame structure are on the 3rd, 4th, and 5th floors while those that occur on the braced structure are on the 5th, 6th, and 7th floors but the experimental perpindahan test is still within the permit limits for structural planning and if reviewed from the driftt ratio results, the results exceed the allowable driftt ratio limit of 2% of the height of each building level located on the 1st and 6th floors of the open frame portal structure and on the 5th floor of the braced portal structure.
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H., Nabil H., and Iqbal A. R. "EVALUATION OF SPECIFIC METHODS TO DETECT CRACK AND DAMAGE OF MECHANICAL BEAM STRUCTURES USING FREE VIBRATION ANALYSIS." Journal of Engineering 15, no. 04 (2024): 4258–79. http://dx.doi.org/10.31026/j.eng.2009.04.11.
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The importance of the beam in the service of our life and how the damaged beam costly influence the economy and even endanger the human life itself, draws our attention to study the specific methods to detect crack and damage by using free vibration analysis of mechanical beam structures. In the present research, three kinds of beam structures have been investigated namely (simply supported beam, portal frame and crane frame) by using finite element method. Six cases of damage are modeled for simply supported beam and portal frame and with seven cases for crane frame. The damage is simulated by reducing the stiffness of assumed elements with ratios (25% and 50 %) in mid- span of the simply supported beam and by introducing cracked elements at different locations with ratio of depth of crack to the height of the beam (a/h) 0.1, 0.25 for simply supported beam and 0.1 and 0.2 for portal and crane frames. A program coded in Matlab 6.5 was used to model the numerical simulation of the damage scenarios. The results showed a decreasing in the five natural frequencies with shifting in the damaged mode shape associated with their frequencies from undamaged beam which means the indication of presence of the damage. The direct comparison gives an indication of the damage but the location of the damage, is not detected. Four structural damage identification methods based on changes in the dynamics characteristics of the beam structures are examined and evaluated for damage scenarios for the three structures considered. The results of the analysis indicate that the curvature energy damage index method performs well in detecting, locating and quantifying damage in single and multiple damage scenarios for the three structures.
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Tang, He Sheng, Jiao Wang, Yu Su, and Song Tao Xue. "Evidence Theory for Uncertainty Quantification of Portal Frames with Semi-Rigid Connections." Advanced Materials Research 663 (February 2013): 130–36. http://dx.doi.org/10.4028/www.scientific.net/amr.663.130.
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The buckling load or the equivalent buckling length factor of the portal frame structures is greatly influenced by stiffness of bracing elements and semi-rigid connections. In engineering the problem parameters (geometrical, material, strength, and manufacturing) are given or considered with uncertainties. The initial rotation stiffness uncertainties are taken into consideration. A differential evolution-based computational strategy for the representation of epistemic uncertainty in a system with evidence theory is developed. An uncertainty quantification analysis for the buckling load of portal frames with semi-rigid connections is presented herein to demonstrate accuracy and efficiency of the proposed method.
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Jia, Wen Wen, and Deng Feng Wang. "Study of Bracing Force Acting at Mid-Span of Beam of Single-Span Portal Frame." Applied Mechanics and Materials 405-408 (September 2013): 869–72. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.869.
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The brace at the mid-span of beam of portal frame provides lateral constraint and improves its overall stability. By the nonlinear finite element method, the influences of structural parameters on the required bracing force for the beam bearing ultimate load were investigated when only one brace acting on the upper flange of beam at mid-span. The bracing force is correlated to the failure mode and configuration of beam of portal frame. The failure of beam trends to be controlled by the strength and the required bracing force increases when the stiffness of column increases. The required bracing force corresponding to the beam subjected to the ultimate load increases when the span of beam or the width of beam flange increases. The research work can be used as reference for the brace design for beam of portal frame.
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Ozola, Lilita, and Janis Fabriciuss. "Numerical and Experimental Analysis of Timber Portal Frame with Semi-Rigid Knee Joints." IOP Conference Series: Materials Science and Engineering 1203, no. 3 (2021): 032008. http://dx.doi.org/10.1088/1757-899x/1203/3/032008.
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Abstract The problems related to development of rotational deformations of a knee joints and crack propagation in rafter elements of timber portal frames were discussed in this article. The rotational displacement, which develops between the rafter and column members due to the bending deformations of the bolts in the knee joint with a simultaneous embedment into the wood, increases the global deformations of the portal frame. Additionally, to axial force and bending moment the rafter elements are heavily loaded with shear force at the sections near knee joint especially. All effects together create very complicated complex of affecting factors. In the current study the design methodology of timber portal frames has been revised with the purpose to develop a more comprehensive set of design conditions for timber portal frames with dowel type fasteners in the knee joints. It is suggested to use the Hoffman failure criterion taking into account the difference of strength in tension and compression to manage the effects of plastic yielding combined with the crack development in wood assumed it as an orthotropic material. It has been proved by case studies of timber portal frames under service loads, as well as by tests and theoretical considerations. The set of design conditions must be supplement by additional clauses comprising Hoffman failure criterion regarding timber sections heavily loaded in shear and cross grain tension. Also, it is recommended that the design capacity of dowel type fastener should be decreased when shear force transferred by the bolt acts perpendicular to the grain direction inducing tension cross grain direction. Other measure may be application of some surface strengthening method.
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Bao Nghi, Le Luong, and Bui Cong Thanh. "A 6DOF super element for nonlinear analysis of composite frames with partial interaction and semi-rigid connections." Vietnam Journal of Mechanics 33, no. 1 (2011): 13–26. http://dx.doi.org/10.15625/0866-7136/33/1/35.
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This paper presents a displacement-based finite element formulation for nonlinear analysis of steel - concrete composite planar frames subjected to combined action of gravity and lateral loads. A 6DOF super element is proposed for modeling composite beam, allowing for partial interaction between the steel beam and the concrete slab, semi-rigid nature of beam to column composite connection and material nonlinearity. The load control method and the displacement control method are utilized for tracing the structural equilibrium paths, and the direct method is utilized for solving the nonlinear problem. Numerical examples, concerning a two-span continuous composite beam, a portal composite frame and a six-storey composite frame, are performed. The results are compared with experience data or theoretical results from other studies and are discussed for influences of the factors mentioned above on behaviour of composite beams and composite frames.
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Obe, Tayo, Chinwuba Arum, and Oladimeji Olalusi. "Optimization of single-span single-storey portal frame buildings." Facta universitatis - series: Architecture and Civil Engineering 17, no. 4 (2019): 359–76. http://dx.doi.org/10.2298/fuace190610021o.
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Many structural designs are done without comprehensive consideration for achieving optimum design. To achieve minimum mass optimization, a mathematical model was developed in this study and subjected to British Standard (BS 5950) code requirements for structural integrity as constraints. Visual basic application (VBA) codes were written into a spreadsheet environment to implement the model. The developed optimization model was validated using different sample shed structures of same volume (729m?) but of different height to span to length (H: b: L) ratios which were obtained using the Ratio method and the Step size method. The best parameter ratio of height to length to breadth obtained was 1:1:1 which is similar to what was obtained by other authors. Parametric design case study analysis was also performed for three different design situations with a given span b, heights H and h and frame spacing S. The minimum masses of steel for a fixed plan area of the buildings were obtained for each of the three scenarios. It is recommended that design engineers should consider varying major frame parameters such as frame spacing and heights at pre-design stages in order to obtain optimal values of parameters which will ensure economical structures.
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Zhong, Xiao Qin, Fei Xing Wei, Ting Hu, and Ying Liu. "Study on Rigidity of Aluminum Alloy Portal-Type Frame Based on Finite Element Method." Advanced Materials Research 1028 (September 2014): 134–38. http://dx.doi.org/10.4028/www.scientific.net/amr.1028.134.
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An aluminum alloy portal-type main frame with double beams is designed in accordance with real production requirements of manufacturer. The working performances of the frame in different structures and under diverse loading conditions, along with the static strength simulation of rigidity on the basis of finite element method are studied, of which the key findings will provide the manufacturers with theoretical foundation for safety production and expand the allocation of aluminum alloy sections.
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Jebur, Hawraa Qasim, and Salah Rohaima Al-Zaidee. "Non-deterministic Approach for Reliability Evaluation of Steel Portal Frame." Civil Engineering Journal 5, no. 8 (2019): 1684–97. http://dx.doi.org/10.28991/cej-2019-03091363.
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In recent years, more researches on structural reliability theory and methods have been carried out. In this study, a portal steel frame is considered. The reliability analysis for the frame is represented by the probability of failure, P_f, and the reliability index, β, that can be predicted based on the failure of the girders and columns. The probability of failure can be estimated dependent on the probability density function of two random variables, namely Capacity R, and Demand Q. The Monte Carlo simulation approach has been employed to consider the uncertainty the parameters of R, and Q. Matlab functions have been adopted to generate pseudo-random number for considered parameters. Although the Monte Carlo method is active and is widely used in reliability research, it has a disadvantage which represented by the requirement of large sample sizes to estimate the small probabilities of failure. This is leading to computational cost and time. Therefore, an Approximated Monte Carlo simulation method has been adopted for this issue. In this study, four performances have been considered include the serviceability deflection limit state, ultimate limit state for girder, ultimate limit state for the columns, and elastic stability. As the portal frame is a statically indeterminate structure, therefore bending moments, and axial forces cannot be determined based on static alone. A finite element parametric model has been prepared using Abaqus to deal with this aspect. The statistical analysis for the results samples show that all response data have lognormal distribution except of elastic critical buckling load which has a normal distribution.
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Xia, Jun Wu, Ling Quan Bu, Zhi Chao Hou, and Xiao Wei Liu. "Research on Additional Internal Force and Deformation of the Portal Frame Construction Caused by Surface Deformation." Advanced Materials Research 163-167 (December 2010): 421–25. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.421.
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This article focuses on the construction of portal frame without crane. The dynamic variational laws of the additional internal force and displacement of the portal frame construction under the elongation, compression, tilt (uneven settlement), positive curvature and negative curvature deformation of ground are calculated by numerical simulation method, using the structural finite element analysis software – ANSYS. We find that the swing column will alter the distribution of the frame construction additional internal force with the surface deformation; and it can effectively restrict additional deformation of the beam, which is caused by the surface deformation. The swing column increased the ability of resist surface deformation of frame construction with compression and uneven settlement deformation; but it reduced the ability of resist surface deformation of frame construction with elongation deformation. Moreover it indicates that the reciprocity between base and foundation will alter the distribution of the frame construction additional internal force with the surface deformation.
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Ummah, Kuntum Chairum, and Achmad Syarifudin. "Corruption case of Base Transceiver Station (BTS) in Indonesia: Framing analysis study of MediaIndonesia.com and Okezone.com." Digital Theory, Culture & Society 1, no. 1 (2023): 53–59. http://dx.doi.org/10.61126/dtcs.v1i1.9.
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The BTS (Base Transceiver Station) construction corruption case of the Minister of Communications and Information, Johny G. Plate, who is also a cadre of the Nasdem Party, has caused a lot of debate among netizens. Online news portals with different party owners are also said to have an impact on the framing of reality and influencing readers' perspectives in viewing the BTS corruption issue. Therefore, it is necessary to further examine how the online media Mediaindonesia.com and Okezone.com framed the corruption case involving Johny G. Plate as the Secretary General of Nasdem Party and former Minister of Communication and Information. The method used in this research is the framing analysis proposed by Robert N. Entman. The subjects of this research are the online media news portals Mediaindonesia.com and Okezone.com, while the objects are news articles about the identification of Johny G. Plate (JP) as a suspect in the BTS Kominfo corruption case. The research results revealed that MediaIndonesia.com tends to view corruption cases with a positive frame by prioritizing the principle of presumption of innocence for not firing Johny G. Plate as Secretary General of the Nasdem Party. In contrast, Okezone.com tends to frame the news by supporting legal efforts to thoroughly investigate the case and supporting a number of DPP Perindo Party stances that seem to be framed as the stance of the news portal.
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Mottershead, J. E., T. K. Tee, C. D. Foster, and R. Stanway. "An Experiment to Identify the Structural Dynamics of a Portal Frame." Journal of Vibration and Acoustics 112, no. 1 (1990): 78–83. http://dx.doi.org/10.1115/1.2930102.
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This paper describes the application of sequential frequency domain techniques to the estimation of mass, stiffness, and damping parameters using measured frequency response functions from a portal frame rig. The theory of the method has been described in the authors’ previous publications. A portal frame is representative of many engineering structures. It is lightly damped and may be thought of as an element of several larger structures such as bridges, transmission towers, and the steel foundations of modern power generating plant. The results offered in this paper are thus of interest to a broad range of engineering problems where it is required to obtain mathematical models in terms of physical parameters.
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Pogonowska-Płatek, Sylwia, and Wojciech Dornowski. "Stability analysis of steel frames according to Eurocode 3." Bulletin of the Military University of Technology 68, no. 2 (2019): 145–63. http://dx.doi.org/10.5604/01.3001.0013.3008.
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In the paper, the qualitative and quantitative comparison of EC3 methods to verify the global stability of the structure is presented. The steel portal frame subjected to varied loads is considered. The initial global sway imperfection and the initial local bow imperfections of member frame are taken into account. The sensitivity of a structure to the 2nd order effects is assessed indirectly using the elastic critical load. The elastic critical load of a frame is calculated according to the buckling mode. The 2nd order effects are taken into account using the finite element method. Keywords: second order effects, steel frame, global stability, critical load.
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Sanjaya, Fajar Putra, Bayzoni Bayzoni, and Eddy Purwanto. "Design of Flat Plate with Equivalent Frame Design Method and Finite Element Method." Jurnal Rekayasa Sipil dan Desain 6, no. 4 (2018): 559–68. https://doi.org/10.23960/jrsdd.v6i4.1115.
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The flate plate is a thick, evenly solid concrete plate that transfers the load directly to the support column without the aid of a beam or shear head or drop panel. This type of plate can be made quickly because of the formwork and simple reinforcement arrangement. The flate plate is planned to be uniform with dimensions of 5000x4000 mm as many as 9 panels, plate thickness of 150 mm with 25 MPa concrete quality, quality of reinforcement 280 MPa and based on the provisions of SNI 1727; 2013 and SNI 2847; 2013. Flat plate analysis uses the equivalent frame design method, finite element method and SAP 2000 and Microsoft Excel programs. Based of the results of the analysis, the comparison value of moments between the portal method equivalent to SAP 2000 is equal to, whereas between finite element methods and SAP2000 is equal to. In the reinforcement plan, the number and diameter of the reinforcement were obtained in terms of the greatest moment value resulting from the analysis of the equivalent frame design method Keywords: Flat plate, Equivalent Frame Design Method, Finite Element Method
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Yan, Wei, Wan Chun Li, and Wei Wang. "Finite Element EMI Model for Cracked Portal Frame and Parameter Study." Applied Mechanics and Materials 226-228 (November 2012): 1181–84. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.1181.
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Based on the three-dimensional finite element method (3D FEM), an electro-mechanical impedance (EMI) model is established for a cracked portal frame. In this analysis, the effect of the interfacial properties between the piezoelectric patches and the host structure on the EMI signatures is considered and thus a coupled structural system consisting of PZT patches, bonding layer and host structure is then investigated. Comparison with numerical results by other methods is made to validate the effectivity and accuracy of the proposed EMI model. The effects of various parameters including the material properties of the adhesive, the crack depth and the crack position etc. on the EMI signatures are highlighted. Numerical results indicate that the present model can be employed for structural damage detection.
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Ding, Jianguo, Wei Zhuang, and Pingxin Wang. "Study on the Seismic Response of a Portal Frame Structure Based on the Transfer Matrix Method of Multibody System." Advances in Mechanical Engineering 6 (January 1, 2014): 614208. http://dx.doi.org/10.1155/2014/614208.
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Portal frame structures are widely used in industrial building design but unfortunately are often damaged during an earthquake. As a result, a study on the seismic response of this type of structure is important to both human safety and future building designs. Traditionally, finite element methods such as the ANSYS and MIDAS have been used as the primary methods of computing the response of such a structure during an earthquake; however, these methods yield low calculation efficiencies. In this paper, the mechanical model of a single-story portal frame structure with two spans is constructed based on the transfer matrix method of multibody system (MS-TMM); both the transfer matrix of the components in the model and the total transfer matrix equation of the structure are derived, and the corresponding MATLAB program is compiled to determine the natural period and seismic response of the structure. The results show that the results based on the MS-TMM are similar to those obtained by ANSYS, but the calculation time of the MS-TMM method is only 1/20 of that of the ANSYS method. Additionally, it is shown that the MS-TMM method greatly increases the calculation efficiency while maintaining accuracy.
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Li, Dong Nan, Jing Yu Wu, and Cun En Chen. "Research of Optimization Design of Structural Concept about Portal Frame." Applied Mechanics and Materials 130-134 (October 2011): 719–24. http://dx.doi.org/10.4028/www.scientific.net/amm.130-134.719.
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There're two issues should be concerned about during the optimization design of structural concept. The one is The using performance of structure, the another is the cost of foundation should be contained in the cost of whole structure. And it is suggested that The cost performance in value engineering should be used during the optimization design of structural concept. In this paper, the method and the process of the optimum structural design is expounded by optimizing a structural concept of project.
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Lin, Xian Gen, and Yong Xu. "The Comparison of Portal Frame Design by Penalty Function Optimization and Traditional Method." Advanced Materials Research 452-453 (January 2012): 348–53. http://dx.doi.org/10.4028/scientific5/amr.452-453.348.
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Yurchenko, Vitalina, Ivan Peleshko, and Nikita Biliaiev. "APPLICATION OF GRADIENT PROJECTION METHOD TO PARAMETRIC OPTIMIZATION OF STEEL LATTICE PORTAL FRAME." International Journal for Computational Civil and Structural Engineering 17, no. 3 (2021): 132–56. http://dx.doi.org/10.22337/2587-9618-2021-17-3-132-156.
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The paper has proposed a mathematical model for parametric optimization problem of the steel lattice portal frame. The design variable vector includes geometrical parameters of the structure (node coordinates), as well as cross-sectional dimensions of the structural members. The system of constraints covers load-carrying capacities constraints formulated for all design sections of structural members of the steel structure subjected to all ultimate load case combinations. The displacements constraints formulated for the specifiednodes of the steel structure subjected to all serviceability load case combinations have been also included into the system of constraints. Additional requirements in the form of constraints on lower and upper values of the design variables, constraints on permissible minimal thicknesses, constraints on permissible maximum diameter-to-thickness ratio for the structural members with circle hollow sections, as well as the conditions for designing gusset-less welded joints between structural members with circle hollow sections have been also considered in the scope of the mathematical model. The method of the objective function gradient projection onto the active constraints surface with simultaneous correction of the constraints violations has been used to solve the formulated parametric optimization problem. New optimal layouts of the steel lattice portal frame by the criterion of the minimum weight, as well as minimum costs on manufacturing and erection have been presented.
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Felix, Jorge L. Palacios, José M. Balthazar, and Reyolando M. L. R. F. Brasil. "On Saturation Control of a Non-Ideal Vibrating Portal Frame Foundation Type Shear-Building." Journal of Vibration and Control 11, no. 1 (2005): 121–36. http://dx.doi.org/10.1177/1077546305047656.
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In this paper, we examine the nonlinear control method based on the saturation phenomenon and of systems coupled with quadratic nonlinear ties applied to a shear-building portal plane frame foundation that supports an unbalanced direct current with limited power supply (non-ideal system). We analyze the equations of motion by using the method of averaging and numerical simulation. The interaction of the non-ideal structure with the saturation controller may lead to the occurrence of interesting phenomena during the forward passage through the several resonance states of the systems. Special attention is focused on passage through resonance when the non-ideal excitation frequency is near the portal frame natural frequency and when the non-ideal system frequency is approximately twice the controller frequency (two-to-one internal resonance).
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Toloue, Iraj, Mohd Shahir Liew, I. S. H. Harahap, and H. E. Lee. "A novel approach to enhance the accuracy of vibration control of Frames." E3S Web of Conferences 34 (2018): 01027. http://dx.doi.org/10.1051/e3sconf/20183401027.
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All structures built within known seismically active regions are typically designed to endure earthquake forces. Despite advances in earthquake resistant structures, it can be inferred from hindsight that no structure is entirely immune to damage from earthquakes. Active vibration control systems, unlike the traditional methods which enlarge beams and columns, are highly effective countermeasures to reduce the effects of earthquake loading on a structure. It requires fast computation of nonlinear structural analysis in near time and has historically demanded advanced programming hosted on powerful computers. This research aims to develop a new approach for active vibration control of frames, which is applicable over both elastic and plastic material behavior. In this study, the Force Analogy Method (FAM), which is based on Hook’s Law is further extended using the Timoshenko element which considers shear deformations to increase the reliability and accuracy of the controller. The proposed algorithm is applied to a 2D portal frame equipped with linear actuator, which is designed based on full state Linear Quadratic Regulator (LQR). For comparison purposes, the portal frame is analysed by both the Euler Bernoulli and Timoshenko element respectively. The results clearly demonstrate the superiority of the Timoshenko element over Euler Bernoulli for application in nonlinear analysis.
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van de Lindt, John W., and R. Karthik Rechan. "Seismic Performance Comparison of a High-Content SDA Frame and Standard RC Frame." Advances in Civil Engineering 2011 (2011): 1–12. http://dx.doi.org/10.1155/2011/478475.
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This study presents the method and results of an experiment to study the seismic behavior of a concrete portal frame with fifty percent of its cement content replaced with a spray dryer ash (SDA). Based on multiple-shake-table tests, the high content SDA frame was found to perform as well as the standard concrete frame for two earthquakes exceeding design-level intensity earthquakes. Hence, from a purely seismic/structural standpoint, it may be possible to replace approximately fifty percent of cement in a concrete mix with SDA for the construction of structural members in high seismic zones. This would help significantly redirect spray dryer ash away from landfills, thus, providing a sustainable greener alternative to concrete that uses only Portland cement, or only a small percentage of SDA or fly ash.
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Silva, N. R. S., L. L. Corso, A. Tamagna, and H. M. Gomes. "Genetic Algorithms and Modal Sensitivity for Damage Detection on Portal Frames." Mecánica Computacional XXV, no. 21 (2006): 1879–92. https://doi.org/10.5281/zenodo.7054640.
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The use of natural frequency as a diagnostic parameter in structural damage detection and vibration monitoring, has been discussed in the last decade for many authors in several works. The large use of natural frequencies and mode shapes as sensitive indicators of structural integrity is due to the fact of the ease in measuring these modal parameters experimentally. Many types of methods are employed in the state of art in damage detection and location using low frequency data. There are two classes of methods that are investigated here: the first is based on frequency sensitivity to the damage and the second one is based on optimization techniques and parametric modeling. In this work a genetic algorithm and a modal sensitivity method are used to identify and evaluate damage cases in a numerical finite element model of a portal frame. The results of the identification and the evaluation of the damage in both methods were similar and could be compared
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Prashant, Gusain, Mahara Solindar, Thakur Riya, Vikramaditya Singh Rajkumar, Ramching Sharad, and Teri Tassar. "Structural Analysis and Design of a G+3 Residential Building: A Comparative Study in Dehradun." Research and Review: Journal of Structural and Building Construction 1, no. 2 (2025): 14–18. https://doi.org/10.5281/zenodo.15385906.
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<em>This paper presents a theoretical exploration of the structural analysis and design process for a G+3 (Ground plus three floors) residential building. The core objective is to compare traditional manual calculation techniques with the capabilities of structural analysis software (specifically STAAD Pro). The analysis considers fundamental load types: gravity loads (dead and live loads, following Indian Standard IS 875) and lateral loads, particularly seismic forces evaluated using the Equivalent Static Method outlined in IS 1893 (Part 1): 2016. Key structural elements like slabs, beams, and columns are designed based on the Limit State Method principles from IS 456:2000. The study contrasts the conceptual basis and application of manual methods (such as Kani's method for gravity frames and the Portal Frame method for lateral loads) against the computational power and precision offered by software. The findings generally show a conceptual alignment between the approaches, affirming the value of understanding manual methods while underscoring the significant advantages of software in handling complex analyses and optimizing designs in contemporary structural engineering.</em> <em> </em>
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Karaton, Muhammet. "Nonlinear Earthquake Analysis of Reinforced Concrete Frames with Fiber and Bernoulli-Euler Beam-Column Element." Scientific World Journal 2014 (2014): 1–15. http://dx.doi.org/10.1155/2014/905963.
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A beam-column element based on the Euler-Bernoulli beam theory is researched for nonlinear dynamic analysis of reinforced concrete (RC) structural element. Stiffness matrix of this element is obtained by using rigidity method. A solution technique that included nonlinear dynamic substructure procedure is developed for dynamic analyses of RC frames. A predicted-corrected form of the Bossak-αmethod is applied for dynamic integration scheme. A comparison of experimental data of a RC column element with numerical results, obtained from proposed solution technique, is studied for verification the numerical solutions. Furthermore, nonlinear cyclic analysis results of a portal reinforced concrete frame are achieved for comparing the proposed solution technique with Fibre element, based on flexibility method. However, seismic damage analyses of an 8-story RC frame structure with soft-story are investigated for cases of lumped/distributed mass and load. Damage region, propagation, and intensities according to both approaches are researched.
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Paullo Muñoz, Luis Fernando, Paulo B. Gonçalves, Ricardo A. M. Silveira, and Andréa Silva. "Nonlinear Resonance Analysis of Slender Portal Frames under Base Excitation." Shock and Vibration 2017 (2017): 1–21. http://dx.doi.org/10.1155/2017/5281237.
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The dynamic nonlinear response and stability of slender structures in the main resonance regions are a topic of importance in structural analysis. In complex problems, the determination of the response in the frequency domain indirectly obtained through analyses in time domain can lead to huge computational effort in large systems. In nonlinear cases, the response in the frequency domain becomes even more cumbersome because of the possibility of multiple solutions for certain forcing frequencies. Those solutions can be stable and unstable, in particular saddle-node bifurcation at the turning points along the resonance curves. In this work, an incremental technique for direct calculation of the nonlinear response in frequency domain of plane frames subjected to base excitation is proposed. The transformation of equations of motion to the frequency domain is made through the harmonic balance method in conjunction with the Galerkin method. The resulting system of nonlinear equations in terms of the modal amplitudes and forcing frequency is solved by the Newton-Raphson method together with an arc-length procedure to obtain the nonlinear resonance curves. Suitable examples are presented, and the influence of the frame geometric parameters and base motion on the nonlinear resonance curves is investigated.
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Yurchenko, V. V., I. D. Peleshko, and Nikita Biliaiev. "Application of improved gradient projection method to parametric optimization of steel lattice portal frame." IOP Conference Series: Materials Science and Engineering 1164, no. 1 (2021): 012090. http://dx.doi.org/10.1088/1757-899x/1164/1/012090.
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Palacios, J. L., J. M. Balthazar, and R. M. L. R. F. Brasil. "On non-ideal and non-linear portal frame dynamics analysis using bogoliubov averaging method." Journal of the Brazilian Society of Mechanical Sciences 24, no. 4 (2002): 257–65. http://dx.doi.org/10.1590/s0100-73862002000400002.
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RAHMAN, MAHBUBUR, YIXIANG XU, JAMES B. P. LIM, et al. "BEHAVIOR OF STEEL PORTAL FRAMES IN FIRE: COMPARISON OF IMPLICIT AND EXPLICIT DYNAMIC FINITE ELEMENT METHODS." International Journal of Structural Stability and Dynamics 13, no. 04 (2013): 1250058. http://dx.doi.org/10.1142/s0219455412500587.
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The use of finite element methods to determine the collapse behavior of steel portal frames in fire requires temperature, large deformation, complex geometry, boundary conditions and degradation of material stiffness to be taken into account. For such analyses, the cost of computation is important as well as the accuracy, robustness and stability of the analyses. The implicit dynamic method is a rigorous technique that considers the equilibrium of every time step. However, convergence may become an issue, particularly if the frame undergoes structural instability while using a direct time incrementation scheme. In contrast, the explicit dynamic method does not require the equilibrium criteria to be met in every time step, and thus convergence problems are not encountered, although the cost of computation may be tremendous if the natural time scale is used. This paper presents a comparison between the efficiency, stability and accuracy of computations using the implicit and explicit dynamic methods, in determining the collapse behavior of portal frames at elevated temperatures; the models are quasi-static since inertia forces are ignored. It is found that similar results can be obtained using both the implicit and explicit dynamic methods, although the analysis times differ significantly. It is shown that, if the applied artificial inertia forces, in terms of residual forces, are magnified and an automatic time incrementation scheme is activated in the implicit dynamic method, then this method shows significant superiority over the explicit dynamic method both in terms of the cost of computation and the accuracy of results obtained for such structures.
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Hari Akbar, Yokta, and Vike Itteridi. "ANALISIS PERENCANAAN STRUKTUR GEDUNG 8 LANTAI DENGAN VARIASI BRACING MENGGUNAKAN APLIKASI PROGRAM ETABS." JURNAL ILMIAH BERING'S 7, no. 01 (2020): 14–18. http://dx.doi.org/10.36050/berings.v7i1.251.
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In planning the construction of buildings located in earthquake-prone areas, especially in the city of natural fences, which are included in earthquake zone 5, namely areas with high levels of earthquake, so that the structural analysis can be planned with the special moment-bearing frame system method (SRPMK) and provides bracing on the portal so that the building structure becomes more rigid. Concentric bracing has a variety of forms including types Z, X, V and Ʌ. This study aimed to plan the safe upper structural eliments from the burdens that occur by adding bracing variations and in accordance with the standards set by the Indonesian National Standards. The object of the study was to compare 2 types of symmetrical structures, namely type 1 in the form of a portal with bracing X and type 2 in the form of a portal with bracing V combined with forms of concentric bracing. Analysis of building planning used ETABS assistance programs. From the result of the analysis of the displacment ETABS program on the three building strucktures it was tend to be almost the same in the X direction which was alapproximately 5-60 mm, while for the y direction the displacement difference was very noticeable due to the addition of type 1 portal bracing stiffener X was 2,4 – 25,4 mm, for type 2 portal bracing V was 2,93 – 29,3 mm, and for ordinary portals was 4,86 – 53,57 mm.
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ZHU, SONGYE, WEN-YU HE, and WEI-XIN REN. "ADAPTIVE-SCALE DAMAGE DETECTION FOR FRAME STRUCTURES USING BEAM-TYPE WAVELET FINITE ELEMENT: EXPERIMENTAL VALIDATION." Journal of Earthquake and Tsunami 07, no. 03 (2013): 1350024. http://dx.doi.org/10.1142/s1793431113500243.
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The superior human vision system provides ingenious insight into an ideal damage detection strategy in which structural modeling scales are not only spatially varying but also dynamically changed according to actual needs. This paper experimentally examines the efficacy of a multi-scale damage detection method based on wavelet finite element model (WFEM). The beam-type wavelet finite element in this study utilizes the second-generation cubic Hermite multi-wavelets as interpolation functions. The dynamic testing results of a one-bay steel portal frame with multiple damages are employed in the experimental validation. Through a multi-stage updating of the WFEM, the multiple damages in the steel portal frame are detected in a progressive manner: the suspected region is first identified using a low-scale structural model, and the more accurate location and severity of the damage can be identified using a multi-scale model with local refinement. As the multi-scale WFEM considerably facilitates the adaptive change of modeling scales, the proposed multi-scale damage detection method can efficiently locate and quantify damage with minimal computation effort and a limited number of updating parameters and sensors, compared with conventional finite element methods.
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Fernández-García, María S., Desirée Rodríguez-Robles, José Ramón Villar-García, and Pablo Vidal-López. "Genetic Algorithm for Cost Optimization of Different Multi-Tunnel Greenhouse Design Alternatives." Agronomy 12, no. 9 (2022): 2145. http://dx.doi.org/10.3390/agronomy12092145.
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Greenhouses are employed worldwide to protect crops from meteorological conditions as well as to control some plant production variables. As multi-tunnel structures are amongst the most used, in this article, we focus on cost optimization of both the steel structure and the concrete foundation of this greenhouse typology. Firstly, three structural alternatives composed of three tunnels and differentiated portal frames were dimensioned conforming to the European design of steel structures, namely, Eurocode 3; meanwhile, the foundation was calculated through a previously validated matrix method. Then, genetic algorithms were employed to optimize for cost each proposed design and to evaluate the relative weight of each element in the overall steel consumption. Moreover, the influence of the greenhouse design on the final cost was also assessed, and it was found that the most cost-effective solution corresponded to the optimized greenhouse alternative exhibiting a 3.5 m separation between portal frames and the combination of a steel profile and plastic gutter (i.e., M3OPT at 15.14 €/m2). Finally, from the study on the influence of the portal frame separation, a further cost per square meter reduction was found for a design with the so-called structural gutter (i.e., steel profile and plastic water collection system) as support for the arches and a 4.5 m separation at 14.21 €/m2.
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Liu, Hong Wei, and Jun Li. "Initial Stiffness Analysis of Steel Portal Frame End-Plate Connections Based on Finite Element Method." Advanced Materials Research 446-449 (January 2012): 867–70. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.867.
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Steel portal frame is easy to build,but the connection styles of end-plate have greater influence on the structure. In this paper, The formula about initial stiffness of end-plate connections has been given.The essay uses ANSYS to analyze the initial stiffness of end-plate connections. Several factors have also been analyzed about the stiffness.The conclusion is that the form of end-plate, thickness, bolt diameter all affect the structural deflections.But these reasons couldn’t change the integral moment of the structure.
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Huang, Zhen, Yong Jun Wu, and Chang Zhang. "Bamboo Strengthened with Carbon Fiber Reinforced Polymer for the Substitutes of Steel Substructures." Key Engineering Materials 517 (June 2012): 233–37. http://dx.doi.org/10.4028/www.scientific.net/kem.517.233.
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This paper presents an investigation on the mechanical properties of bamboos Mao Zhu (Phyllostachys Pubescens) strengthened with carbon fiber reinforced polymer (CFRP) and used as the substitute of steel substructures for a low carbon construction. At first, a series experimental study is carried out to investigate the compressive strength, bending strength and tensile strength of Mao Zhu, which is strengthened with CFRP by different ways. Then the mechanical properties of bamboos with different strengthening methods of CFRP are compared. The most efficient strengthening method is suggested for the carbon fiber strengthened bamboos, with such method the compressive strength and bending strength of Mao Zhu could be increased more than 30% and 44% compared with that of Mao Zhu without strengthening. Finally this paper discusses the advantages of the carbon fiber strengthened bamboos used as the substitutes of the steel substructures, for example the purlins and bracings of steel portal frame structures. The effective use of the bamboos as the substitutes of steel substructures will reduce the steel amount used in the steel portal frame structure, which is commonly used as low-rise factory building structure worldwide.
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Maida, Yusuke, and Hiroyasu Sakata. "Cyclic loading test of reinforced concrete frames protected with brace-type friction dampers." Advances in Structural Engineering 25, no. 1 (2021): 83–97. http://dx.doi.org/10.1177/13694332211042785.
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In this study, cyclic loading tests were conducted on reinforced concrete (RC) portal frames with brace-type friction dampers. The boundary conditions that could reproduce the axial forces exerted on the beams were adopted. To resist the axial force acting on the RC member, a damper connection method was employed by using steel inserted through the center of the RC member. The purpose of this study was to a) understand the behavior of the damper connection and the RC frame with brace-type friction dampers based on experimental tests and b) to confirm the effectiveness of the new connection method. According to the test results, the proposed connection method achieved effective damper connections in the RC frames. For the RC frame specimens with dampers, it was confirmed that the damper reached its sliding force and started to dissipate energy at an early stage with story drift ratios smaller than those at RC beam yielding. The welded part of the gusset plate and the steel inserted through the center of the RC beam were broken. When the welded part inside the beam broke and the axial deformation of the beam increased, the sliding displacement of the damper decreased. Therefore, a reliable jointing method of this part needs to be established.
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Nishiyama, M., H. Mugurama, and F. Watanabe. "Hysteretic restoring force characteristics of unbounded prestressed concrete framed structure under earthquake load." Bulletin of the New Zealand Society for Earthquake Engineering 22, no. 2 (1989): 112–21. http://dx.doi.org/10.5459/bnzsee.22.2.112-121.
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An analytical method, by which hysteretic restoring force characteristics of unbonded prestressed concrete framed structure can be statically pursued on the basis of material properties, is presented. The bond-slip relationship between concrete and prestressing tendon is taken into account, and thus the method covers unbonded members and bonded members. For verifying the propriety of the analytical method, the experiment is carried out on a portal frame with an unbonded prestressed concrete beam of 4.2 m in length and reinforced concrete columns of 1 m in height. High intensity reversed cyclic lateral loading is applied. The experimental results show a good agreement with the analytical ones in terms of load-deflection relation and the fluctuation of the tendon stress at anchorage end.
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AU, F. T. K., and Z. H. YAN. "DYNAMIC ANALYSIS OF FRAMES WITH MATERIAL AND GEOMETRIC NONLINEARITIES BASED ON THE SEMIRIGID TECHNIQUE." International Journal of Structural Stability and Dynamics 08, no. 03 (2008): 415–38. http://dx.doi.org/10.1142/s0219455408002727.
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This paper presents a method for nonlinear dynamic analysis of frames with material and geometric nonlinearities which is based on the semirigid technique. The plastic hinge that accounts for the material nonlinearity is modeled as a pseudo-semirigid connection with nonlinear hysteretic moment-curvature characteristics at the element ends. The stiffness matrix of a frame element with material and geometric nonlinearities is expressed as the sum of products of the standard stiffness matrix and the geometric stiffness matrix of the element, with their corresponding correction matrices based on the plasticity factors developed from the section flexural stiffness at the plastic hinge locations. The combined stress yield condition is used for the force state determination of plastic hinges, and force equilibrium iterations and geometry updating for frames are carried out in every time step. When the key parameters of a structure are updated in a time step, the time step is split up into substeps to ensure accuracy while keeping the computations to a reasonable amount. The plastic rotation history can be calculated directly or in an approximate indirect way. The method is computationally efficient and it needs no additional connection elements, which makes it convenient for incorporation into existing linear dynamic analysis programs. Besides, the method can handle accurately and efficiently the dynamic analysis of nonlinear frames using relatively large time steps in conjunction with time step subdivision to cope with key parameter changes. A portal frame is used to verify the correctness of the proposed method. A more complicated five-story frame is used to illustrate the applicability and performance of the proposed method.