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1
Mohammad, Shahiq Khan, El-Naggar Samir, M. Soliman Mohamed, Shalaby Samir, and Islam Saiful. "Vibration of Semi Rigid Foundation Locating on Elastic Half Space." International Journal of Novel Research in Civil Structural and Earth Sciences 9, no. 2 (2022): 8–15. https://doi.org/10.5281/zenodo.6556936.
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<strong>Abstract</strong><strong>:</strong> In this research work, the vibration reaction of a massless or massive raft foundation is investigated. The raft foundation is located on a homogeneous linear-elastic half space and faced to external dynamic loads. The elastic half space, signifying the medium of soil, is formulated by a semi analytical method in a complex response. Hence, this work is analyzed in time-domain by employing inversion fast Fourier transformation for impedance coefficients of subgrade soil. The foundation mat has to be discretized into a number of finite elements, which are combined with the corresponding sub regions of the elastic half-space through compatibility and equilibrium conditions. The proposed approach yields results which are in good agreement with those obtained in previous studies. Numerically works are shown to observe the influence of relative stiffness and aspect ratio of the foundation on the raft reaction. <strong>Keywords:</strong> Dynamic loads, Elastic half space, Foundation, Semi analytical method, Semi rigid foundation, Vibration. <strong>Title:</strong> Vibration of Semi Rigid Foundation Locating on Elastic Half Space <strong>Author:</strong> Mohammad Shahiq Khan, Samir El-Naggar, Mohamed M. Soliman, Samir Shalaby, Saiful Islam <strong>International Journal of Novel Research in Civil Structural and Earth Sciences</strong> <strong>ISSN 2394-7357</strong> <strong>Vol. 9, Issue 2, May 2022 - August 2022</strong> <strong>Page No: 8-15</strong> <strong>Novelty Journals</strong> <strong>Website: www.noveltyjournals.com</strong> <strong>Published Date: 17-May-2022</strong> <strong>DOI: https://doi.org/10.5281/zenodo.6556936</strong> <strong>Paper Download Link (Source):</strong> <strong>https://www.noveltyjournals.com/upload/paper/Vibration%20of%20Semi%20Rigid-17052022-4.pdf</strong>
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Li, Wei, Xiaojuan Li, Tengfei Wang, Qian Yin, and Mingxing Zhu. "The Simplified Method of Head Stiffness Considering Semi-Rigid Behaviors of Deep Foundations in OWT Systems." Buildings 14, no. 6 (2024): 1803. http://dx.doi.org/10.3390/buildings14061803.
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Simplified methods of static free head stiffness of the semi-rigid foundation under lateral loads were limited to flexible or rigid behavior by the critical length of piles. This would lead to errors when predicting the static or dynamic performance of their upper structures in OWT Systems. This paper presents a comprehensive analysis of the head static stiffness of the semi-rigid pile without considering the critical length. Firstly, case studies using the energy-based variational method encompassing nearly twenty thousand cases were conducted. These cases involved different types of foundations, including steel pipe piles and concrete caissons, in three types of soil: homogeneous soil, linearly inhomogeneous soil, and heterogeneous soil. Through the analysis of these cases, a series of polynomial equations of three kinds of head static stiffness, containing the relative stiffness of the pile and soil, the slenderness ratio, and Poisson’s ratio, were developed to capture the semi-rigid behavior of the foundations. Furthermore, the lateral deflection, the rotation for concrete caissons in the bridge projects, and several natural frequencies of three cases about the OWT system considering the SSI effect were carried out. the error of high-order frequency of the OWT system reached 13% after considering the semi-rigid effect of the foundation.
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Li, Xiao, Min Ding, and Xiu Gen Jiang. "Theoretical Analysis of the Sole Plate of Semi-Rigid Light Steel Column Footings on the Basis of Winkler Model of Elastic Foundation Beam." Advanced Materials Research 660 (February 2013): 105–10. http://dx.doi.org/10.4028/www.scientific.net/amr.660.105.
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To obtain the pressure distribution model on the sole plate of semi-rigid light steel column footing, the deflection formulas of beams with free ends on elastic foundation subjected to arbitrarily concentrated load and arbitrarily trapezoidal load were developed by applying the Winkler model of elastic foundation beam and initiate-parameter expressions of deformation and internal force by presetting boundary condition and calculating with Maple software. The sole plate of semi-rigid square steel tube column footing was converted into elastic foundation beam which is supported by concrete foundation, the mechanical model of the sole plate subjected to eccentric load was obtained, and the theoretical solution of pressure distribution on the sole plate was presented. Then the theoretical solution was compared with the numerical solution via an example. The results show that the two solutions meet well with each other, and there is much great difference between the pressure distribution on sole plate of semi-rigid light steel column footing and the linear pressure distribution model in common use. As a result, the semi-rigid column footing stiffness would be overestimated by using linear pressure distribution model. The fruits presented in this paper are useful and convenient to the design of semi-rigid light steel column footing.
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Su, Li Ya. "Mechanics Analysis of Semi-Rigid Subgrade Pavement Structure." Applied Mechanics and Materials 580-583 (July 2014): 105–8. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.105.
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The semi-rigid base asphalt pavement structure was choose often used to the highway in our country, but the semi-rigid base asphalt pavement early damage almost has become a common phenomenon.In this paper, the rule and trend of mechanics response about pavement structure (the vertical displacement and tensile stress) were analyzed under the semi-rigid base choose different elasticity modulus and thickness by ANSYS for muti-layer foundation of semi-rigid base pavement design to provide reference.
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Cao, Fengxu, Chaoliang Ye, Zhenxu Wu, Zitong Zhao, and Hao Sun. "Settlement Calculation of Semi-Rigid Pile Composite Foundation on Ultra-Soft Soil under Embankment Load." Buildings 14, no. 7 (2024): 1954. http://dx.doi.org/10.3390/buildings14071954.
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Ultra-soft soil is distributed in coastal areas around the world and has poor engineering properties. There is a significant difference in settlement between semi-rigid pile and surrounding soil under embankment load. Based on existing research results, the settlement calculation formula of ultra-soft soil composite foundation reinforced by semi-rigid pile is derived in this paper. Based on the Alamgir displacement model, assuming a three-zone model of pile skin friction with a negative skin friction plastic zone in the upper part of the pile, an elastic zone in the middle part of the pile, and a skin friction-bearing plastic zone in the lower part of the pile, the upward and downward penetrations of pile, and pile–soil slip deformation characteristics are considered. Analytical expressions for settlement calculations of semi-rigid pile composite foundations under embankments were derived based on differential equations for pile–soil load transfer in the unit cell. The influences of pile diameter and the compression modulus of the underlying layer at the pile end on the settlement characteristics of the semi-rigid pile composite foundation are discussed. The results show that the derived theoretical calculation method is in good agreement with the field measurement and laboratory model test results. Ultra-soft soil composite foundations have long settlement stabilization times and large settlement deformations. Penetration deformation occurs at the semi-rigid pile end. The relationship between pile end resistance and pile end piercing deformation is hyperbolic. The compression modulus of the underlying layer has a great influence on pile end penetration. The lower the compression modulus of the underlying layer, the larger the penetration deformation of pile end. The larger the pile diameter is, the smaller the penetration deformation is.
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Han, Zejun, Mi Zhou, Xiaowen Zhou, and Linqing Yang. "Dynamic Response of 3D Surface/Embedded Rigid Foundations of Arbitrary Shapes on Multi-Layered Soils in Time Domain." International Journal of Structural Stability and Dynamics 19, no. 09 (2019): 1950106. http://dx.doi.org/10.1142/s0219455419501062.
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Significant differences between the predicted and measured dynamic response of 3D rigid foundations on multi-layered soils in the time domain were identified due to the existence of uncertainties, which makes the issue a complicated one. In this study, a numerical method was developed to determine the dynamic responses of 3D rigid surfaces and embedded foundations of arbitrary shapes that are bonded to a multi-layered soil in the time domain. First, the dynamic stiffness matrices of the rigid foundations in the frequency domain are calculated via integral domain transformation. Secondly, a dynamic stiffness equation for rigid foundations in the time domain is established via the mixed variables formulation, which is based on the discrete dynamic stiffness matrices in the frequency domain. The proposed method can be applied to the treatment of systems with multiple degrees of freedom without losing the true information that concerns the coupling characteristics. Numerical examples are presented to demonstrate the accuracy of the proposed method for predicting the horizontal, vertical, rocking, and torsional vibrations. Further, a parametric study was carried out to provide insight into the dynamic behavior of the soil–foundation interaction (SFI) while considering soil nonhomogeneity. The results indicate that the elastic modulus of the soil has a significant impact on the dynamic responses of the rigid foundation. Finally, a numerical example of a rigid foundation resting on a six-layered, semi-infinite soil demonstrates that the proposed method can be used to deal with multi-layered media in the time domain in a relatively easy way.
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Liu, Zeng Rong, Qing Juan Sun, and Zhi Fang Yan. "The Analysis on Bearing Characteristic of Residue Pile Composite Foundation Formed by DDC." Applied Mechanics and Materials 580-583 (July 2014): 302–7. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.302.
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The bearing capacity of residue pile composite foundation formed by deep dynamic compaction, shorted for DDC, is calculated and analyzed by ANSYS finite element software. The analysis results show that pile body and soil between piles have a good coordination, residue pile composite foundation is semi-flexible and semi-rigid and the effect of consolidating foundation is obvious. The purpose of foundation treatment should be taken into consideration primarily to provide reference for future similar projects.
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Quek, Ser Tong, and Chan Ghee Koh. "Limit load analysis of a semi-infinite beam on rigid foundation." International Journal of Mechanical Sciences 33, no. 5 (1991): 403–12. http://dx.doi.org/10.1016/0020-7403(91)90078-h.
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Prakash, Jay, Ayşe Turhan Daloğlu, and Korhan Özgan. "An optimal design approach for steel space frames with T-stub semi-rigid connections considering soil-structure interaction." Journal of Structural Engineering & Applied Mechanics 7, no. 2 (2024): 104–23. http://dx.doi.org/10.31462/jseam.2024.02104122.
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An optimization technique for designing the steel space frame with T-stub semi-rigid connections and interaction between soil and structure is presented in this article. A three-parameter-based elastic foundation model is utilized to investigate soil-structure interactions (SSI). To enable two-way data transfer for all optimization methods, computer software was developed using C# version 17.8.6, which connects to SAP2000-OAPI version 22. Particle swarm optimization (PSO) and teaching-learning-based optimization (TLBO) are employed for optimal designs. These optimization techniques choose profile sections from a list, including 64W discrete sections from the American Institute of Steel Construction (AISC). The Load and Resistance Factor Design-American Institute of Steel Construction (LRFD-AISC) strength constraints, geometric constraints, inter-storey drift constraints, and displacement constraints are considered during optimization. The first phase entails creating optimal designs for two unique steel space frames that consider SSI but do not include T-stub semi-rigid connections. Following that, the same optimization procedures are carried out with T-stub semi-rigid connections. The parameters needed for the foundation model are obtained through soil surface displacements. Utilizing T-stub semi-rigid connections while considering the interaction between the structure and the soil produces increased structural weight.
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Zlatkov, Dragan, Slavko Zdravkovic, Marina Mijalkovic, Biljana Mladenovic, and Tomislav Igic. "Redistribution of the influences in systems with semi-rigid joints on elastic foundations." Facta universitatis - series: Architecture and Civil Engineering 8, no. 2 (2010): 225–34. http://dx.doi.org/10.2298/fuace1002225z.
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Most often, in the case of typefied prefabricated systems, foundations are designed and constructed as prefabricated elements as well. When the structure is exposed to high intensity loading and founded on a weak soil, beam foundations are often used instead of pad foundations. Beam foundations, stiffening girders, as well as beams which support the fa?ade elements or partition walls, are treated as beams on elastic foundations, while joint of these girders to pad foundations or vertical support elements of a precast structure can be treated as semi-rigid. Modeling of systems with semi-rigid joints on elastic foundations, for different levels of rigidity of connections, is illustrated by an example of a frame under static loading. On the basis of the results of the calculation carried out in this paper, it is evident that taking into account the elastic foundations of the member and the corresponding degree of fixation of the member on this foundations significantly affects the magnitude of the forces in the cross-sections of the member, and on the redistribution of influences in the entire structure. Yet, the foundations-and-soil interaction exerted the highest influence on the magnitude of the stress in the foundation structure itself.
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M.E. Kartal, H.B. Basaga, A. Bayraktar, and M. Muvafık. "Effects of Semi-Rigid Connection on Structural Responses." Electronic Journal of Structural Engineering 10 (January 1, 2010): 22–35. http://dx.doi.org/10.56748/ejse.10122.
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There are several idealizations in numerical analysis of structures. In the joints and supports, which is usually assumed to be pinned or rigid, semi-rigid connection should be considered to obtain more realistic, reliable and also economical results. In this study, rotational spring stiffness-connection ratio relation is clearly explained and revealed. A finite element program SEMIFEM is developed in FORTRAN language for the numerical analysis. This program provides to define semi-rigid connections in terms of rotational spring stiffness or connection ratio simultaneously. In the numerical applications, rotational spring stiffness - connection percentage relation of the semi-rigid connected structural members is submitted. Semi-rigid connections are considered in column-to-foundation connection of a portal frame, beam-to-column connection of a prefabricated structure, steel brace connection to reinforced concrete (RC) frame of a steel X-braced RC frame and truss member connection to joint of a steel truss system. The variation of moment, shear force, axial force, displacement and stress is investigated in a selected axis of the structures. Numerical examples are performed with respect to connection percentage of the related structural members by using finite element method. According to finite element analysis results, the degree of the semi-rigid connection is important as much as its existence in the design phase. This study reveals that the effect of semi-rigid connections on structural systems shows different variations from structure to structure.
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Mukti, Dimas Andaru, Ary Setyawan, and Bambang Setiawan. "Analysis of Rigid Pavement Design with Micropile Foundation." IOP Conference Series: Earth and Environmental Science 1381, no. 1 (2024): 012019. http://dx.doi.org/10.1088/1755-1315/1381/1/012019.
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Abstract Micropile is a foundation technology that can be used on rigid pavement constructions that have soft soil foundations with low soil bearing capacity. Deflections and moments that occur on rigid pavements are analyzed with the addition of micropile foundations and without using micropiles. Loading is simulated with a semi-trailer truck, the first loading is on the edge of the plate and the second is in the middle of the plate. The largest deflection value occurs with the results of testing with the micropile placing the load on the edge of 0.3879 mm, and the plate without using a micropile shows a result of 0.4145 mm while the maximum limit for concrete deflection is 0.4 mm so that loading without using a micropile exceeds the deflection capacity. Whereas for loading in the middle with a micropile the results were 0.3563 mm and 0.3564 mm without using a micropile. So that the placement of the micropile is very influential to withstand the deflection that occurs. The biggest moment occurred on the plate without using a micropile with a moment value of 18.758 kNm while when using a micropile the moment that occurred was 18.465 kNm and was sufficient for structural safety.
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Jo, Myoung Su, Ki Tae Lee, Ho Deok Kang, Hong Bum Cho, and Tien Dung Nguyen. "Point Foundation (PF) method: Principles and recent research findings." Journal of Science and Technology in Civil Engineering (STCE) - NUCE 14, no. 3 (2020): 53–66. http://dx.doi.org/10.31814/stce.nuce2020-14(3)-05.
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Conventionally, cement deep mixing (CDM) columns are designed to have constant diameters over the improved depth as this facilitates the construction procedures. However, this design pattern may be inefficient in cases of spread footings or shallow foundations. This paper first briefly introduces principles, construction procedures and quality control techniques of an innovative CDM method that can create head-enlarged column, named as Point Foundation (PF). The method is practically implemented with a specific binder that is environment-friendly and more effective in strength enhancing compared with the common binder as cement. Static load tests on three instrumented PF columns indicate that the variation trend of induced vertical stress profile along the columns in general is similar to that under the centre of shallow footings on elastic soil medium. However, the stress profile in the (semi-rigid) PF columns is larger than that in elastic soil but less than that in (rigid) PHC pile. This confirms the load transfer mechanism along semi-rigid columns like CDM/PF. Test results also indicate that at the depth of one to two times head diameters the induced stress remains just 20% the applied pressure. Findings on the trend of the induced vertical stress in the columns suggests that the settlement of common shallow footings on CDM/PF column-reinforced grounds should be evaluated using 3D condition taking into account the fact that the induced stress decreases with depth.
 Keywords:
 ground improvement; Point Foundation (PF); tapered cross section; load transfer mechanism; load-settlement behavior.
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Le, Thang H., and Vincent W. Lee. "Out-of-plane (SH) soil-structure interaction: Semi-circular rigid foundation revisited." Soil Dynamics and Earthquake Engineering 66 (November 2014): 149–56. http://dx.doi.org/10.1016/j.soildyn.2014.06.031.
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Aristizabal-Ochoa, J. Dario. "Stability of slender columns on an elastic foundation with generalised end conditions." Ingeniería e Investigación 33, no. 3 (2013): 34–40. http://dx.doi.org/10.15446/ing.investig.v33n3.41041.
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Slender columns' lateral stability under compressive axial loads is presented, with uninhibited, partially inhibited and totally inhibited end side-sway, including the effects of semi-rigid connections and a uniformly distributed lateral elastic foundation (Winkler's type) throughout its entire span. The proposed classification of prismatic columns on an elastic foundation and the corresponding stability equations are general and relatively simple to apply, yielding exact results when compared to other analytical methods. The buckling load was obtained by making the determinant of a 4 x 4 matrix equal to zero for columns having side-sway uninhibited or partially inhibited at both ends, and of a 3 x 3 matrix for columns having side-sway inhibited at one or both ends. The effect of semi-rigid connections on the buckling load of five classical column cases is fully discussed and the results compared to those arising from other analytical methods.
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COSTA, R. R. R., M. C. V. LIMA, G. M. S. ALVA, and E. S. MAGALHÃES. "Optimization of the bending stiffness of beam-to-column and column-to-foundation connections in precast concrete structures." Revista IBRACON de Estruturas e Materiais 10, no. 5 (2017): 985–97. http://dx.doi.org/10.1590/s1983-41952017000500003.
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Abstract This work involved the structural optimization of precast concrete rigid frames with semi-rigid beam-to-column connections. To this end, several frames were simulated numerically using the Finite Element Method. Beams and columns were modeled using bar elements and their connections were modeled using spring elements, with variable bending stiffness. The objective function was based on the search of the least stiff connection able to ensure the global stability of the building. Lastly, a connection model with optimal stiffness was adopted to design the frame. Semi-rigid beam-to-column connections with a constraint factors of 0.33 sufficed to ensure the maximum allowable horizontal displacement and bending moment of the connection, with a global stability parameter of 1.12. This confirms that even connections with low constraints generate significant gains from the structural standpoint, without affecting construction and assembly-related aspects.
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Yin, Ling Feng, Long Tan, Gan Tang, Min Zhang, and Zhao Xin Zheng. "Structure Composition and Mechanical Principle of Assembled Self-Supported Warehouse." Advanced Materials Research 838-841 (November 2013): 574–78. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.574.
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This paper describes the structure composition and characteristic of assembled self-supported warehouse. And its mechanical principle is introduced and compared with both the assembled pallet rack and the building structure. The assembled self-supported warehouse combines the two structure systems effect. The longitudinal horizontal load is transferred to foundation by means of roof truss and multi-pan portal rigid frame and the lateral horizontal load is transferred by means of spine bracing system and semi-rigid frame. Load on roof and goods load are transferred separately from roof truss and beams to columns, then these loads are transferred to foundation.
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Vu, Anh Q., and Roberto T. Leon. "Vibration analysis of steel frames with semi-rigid connections on an elastic foundation." Steel and Composite Structures 8, no. 4 (2008): 265–80. http://dx.doi.org/10.12989/scs.2008.8.4.265.
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Wang, Jing-feng, Hai-Tao Wang, Wei-Wei Shi, and Hong-Yu Sheng. "Temperature analysis of extended end plate joints to square CFST columns in fire." Journal of Structural Fire Engineering 7, no. 4 (2016): 306–15. http://dx.doi.org/10.1108/jsfe-12-2016-021.
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Purpose This paper aims to obtain fire resistance of semi-rigid joints for concrete-filled steel tubular (CFST) composite frames and temperature filed distribution of composite joints in fire. Design/methodology/approach The temperature filed model of semi-rigid joints to CFST columns with slabs was made by using ABAQUS finite element (FE) software, in considering temperature heating-up stage of fire modelling. The effects of composite slab, fire type and construction location were discussed, and the model was verified by the test results. The temperature distribution of composite joint under three-side or four-side fire condition was studied by the sequentially coupled thermal analysis method. The temperature versus time curves and temperature distribution of various construction and location were analyzed. Findings The paper provides FE analysis and numerical simulation on temperature field of semi-rigid joints for CFST composite frames in fire. The effects of composite slab, fire type and construction location were discussed, and the model was verified by the test results. It suggests that the temperature distribution of composite joint in three- or four-side fire condition showed a different development trend. Research limitations/implications Because of the chosen FE analysis approach, the research results may lack generalizability. Therefore, researchers are encouraged to test the proposed propositions further. Practical implications The research results will become the scientific foundation of mechanical behavior and design method of semi-rigid CFST composite frames in fire. Originality/value This paper fulfils an identified need to study the temperature field distribution of the semi-rigid joints to CFST columns and investigate the mechanical behavior of the semi-rigid CFST joints in fire.
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Morfidis, K., and I. E. Avramidis. "Formulation of a generalized beam element on a two-parameter elastic foundation with semi-rigid connections and rigid offsets." Computers & Structures 80, no. 25 (2002): 1919–34. http://dx.doi.org/10.1016/s0045-7949(02)00226-2.
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Taylor, Adam G., and Jae H. Chung. "Explanation and Application of the Evolving Contact Traction Fields in Shallow Foundation Systems." Geotechnics 2, no. 1 (2022): 91–113. http://dx.doi.org/10.3390/geotechnics2010004.
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The present paper provides a qualitative discussion of the evolution of contact traction fields beneath rigid shallow foundations resting on granular materials. A phenomenological similarity is recognized in the measured contact traction fields of rigid footings and at the bases of sandpiles. This observation leads to the hypothesis that the stress distributions are brought about by the same physical phenomena, namely the development of arching effects through force chains and mobilized intergranular friction. A set of semi-empirical equations are suggested for the normal and tangential components of this contact traction based on past experimental measurements and phenomenological assumptions of frictional behaviors at the foundation system scale. These equations are then applied to the prescribed boundary conditions for the analysis of the settlement, resistance, and stress fields in supporting granular materials beneath the footing. A parametric sensitivity study is performed on the proposed modelling method, highlighting solutions to the boundary-value problems in an isotropic, homogeneous elastic half-space.
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ISHIZAKI, Sadayuki, Kohji TOKIMATSU, and Toshiaki NAGAO. "SEISMIC PERFORMANCE OF PILE FOUNDATION WITH SEMI-RIGID PILE HEAD CONNECTIONS IN LIQUEFIABLE SOIL." Journal of Structural and Construction Engineering (Transactions of AIJ) 78, no. 692 (2013): 1749–58. http://dx.doi.org/10.3130/aijs.78.1749.
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Huang, HY, L. Li, F. Liu, and GJ Zhou. "Seismic Characteristics of Integral Abutment Bridge with Rigid-Flexible Combined Abutment Based on Shaking Table Model Test." Journal of Physics: Conference Series 2476, no. 1 (2023): 012020. http://dx.doi.org/10.1088/1742-6596/2476/1/012020.
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Abstract Aiming at the problem that the strong structure-soil interaction of rigid abutment integral bridge and semi-flexible abutment integral bridge, a new integral abutment bridge with rigid-flexible abutment was proposed, and the shaking table model test was carried out to study its seismic performance. The test result shows that at the seismic fortification intensity 6, the specimen are relatively intact, and no crack was generated, which shown the integral abutment bridge with rigid-flexible combined abutment has good seismic performance. The first-order and second-order frequency of integral abutment bridge with rigid-flexible combined abutment are about 5.0 Hz and 10 Hz, respectively. The damping ratio coefficient of rigid-flexible combined abutment-pile-soil system is about 0.18~0.25. The soil-rigid-flexible combined abutment-pile interaction amplified from 10.71 times the pile diameter above the bottom of the pile foundation. The maximum dynamic amplification factor of specimen and soil are located at the abutment bottom and the soil surface, respectively.
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Gan, Buntara S., Sofia W. Alisjahbana, Irene Alisjahabana, and Shota Kiryu. "Semi analytical solution of a rigid pavement under a moving load on a Kerr foundation model." Journal of Vibroengineering 20, no. 5 (2018): 2165–74. http://dx.doi.org/10.21595/jve.2018.20082.
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Sosenushkin, Evgeny, Oksana Ivanova, Elena Yanovskaya, and Yuliya Vinogradova. "Mathematical Modeling of Vibration Dampers of Vibration-Insulated Structures." EPJ Web of Conferences 248 (2021): 02009. http://dx.doi.org/10.1051/epjconf/202124802009.
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Vibration dampers are installed on the machine foundations in order to reduce the vibration level. Such technological solutions are most expedient in the case of a harmonic load with a low instability of the vibration frequency. Unfortunately, dampers do not provide such a large reduction in the dynamic effect on the base, as vibration isolation, but in some cases their efficiency turns out to be quite sufficient with a relatively simple implementation and low manufacturing cost. The use of dynamic vibration dampers gives a great effect when an increased vibration of foundations occurs during the operation of equipment in metallurgical production, for example, when processing materials by pressure, reconstructing enterprises and replacing heavy equipment. During the operation of heavy forging equipment and manipulators for various purposes, the foundations of these devices can be considered as a rigid body. The model soil on which this foundation is installed can be considered a homogeneous elastic isotropic half-space. When calculating with such mathematical models, one can use solutions of the corresponding dynamic contact problems. A comparative analysis of the effectiveness of damping foundation vibrations using different foundation models, including the model of an elastic, homogeneous half-space and a system of semi-infinite rods, the modulus of elasticity of which increases with depth according to the quadratic law, shows a fairly close agreement.
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Malhotra, P. K., and A. S. Veletsos. "Energy Method for Base Uplifting Analysis of Liquid-Storage Tanks." Journal of Pressure Vessel Technology 118, no. 3 (1996): 332–35. http://dx.doi.org/10.1115/1.2842196.
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A solution, based on Ritz energy method, is presented for the uplifting analysis of a uniformly loaded semi-infinite beam supported on a rigid foundation. Motivated by a need to understand the effects of earthquake-induced base uplifting in unanchored liquid-storage tanks, the solution accounts for the nonlinearities associated with large displacements and material yielding in the base plate, and considers the constraining action of the tank wall. The results are in close agreement with those from the “exact” analysis.
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Gečys, Tomas, Alfonsas Daniūnas, Kęstutis Gurkšnys, and Konstantin Rasiulis. "EXPERIMENTAL INVESTIGATION OF GLUED LAMINATED TIMBER BEAM-TO-BEAM CONNECTION / KLIJUOTOSIOS MEDIENOS SIJOS ELEMENTŲ TARPUSAVIO JUNGTIES EKSPERIMENTINIS TYRIMAS." Engineering Structures and Technologies 5, no. 1 (2013): 11–19. http://dx.doi.org/10.3846/2029882x.2013.777018.
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Semi rigid mounting joints of glued laminated timber elements are connections that are fully assembled on construction site and capable to handle bending moments, axial and shear forces. The need for new type of semi rigid timber elements’ connection is obvious. The manufacturing possibilities of glued laminated timber elements’ are wide: straight element's length may extend up to 40 m or curved axis elements with dimensions of up to 10 meters in height, therefore, manufacturers, erectors and others face with transportation problems of non-standard, oversized elements. Semi-rigid mounting joints are used to solve this problem. In factory non-standard, oversized, glued, laminated timber elements are cut into standard transportation dimensions and fully mounted into integral element on construction site, using semi rigid mounting joints. In this article semi-rigid, glued, laminated timber elements’ joints which are used as beam to beam, beam to column and column to foundation connections are analysed. Also the main design principles of semi-rigid joints are discussed. The new type of semi rigid beam to beam connection is proposed and experimentally analysed. The experimentally and theoretically analysed connection is composed of welded steel details which are anchored into timber element. The main experiment is four point bending; the analysed connection is in the middle of the span. The beam's span is 3.20 m; the dimensions of the timber element's cross section are: width 200 mm; height 400 mm; mounting bolts are M16. Glued laminated timber strength class is GL24h. The tight contact between timber element and steel detail is created by anchoring steel detail's T shape part into timber element. The initial movement between timber element and steel detail is eliminated using fillers. Two types of fillers are used in these experiments: two component polyurethane and cement based filler with polymer fibres. Two joints with different fillers are tested in laboratory experiments. Bending bearing capacity and stiffness (displacements) of the joints’ are determined in laboratory. Experimental bearing capacities are compared with theoretical calculations according to European (EC5) and Lithuanian timber structures design codes. Conclusions and recommendations are presented for further experiments and computer simulations. Santrauka Straipsnyje analizuojami pusiau standūs montuojamieji klijuotosios medienos konstrukcijų mazgai, kurie naudojami elementams sujungti per ilgį, rėmų kampinėms jungtims tarp kolonos ir sijos bei jungtims tarp kolonos ir pamato. Aptariami pagrindiniai pusiau standžių montuojamųjų medinių konstrukcijų mazgų konstravimo principai. Pasiūlytas ir eksperimentiškai tirtas per ilgį sujungtų lenkiamųjų klijuotosios medienos sijos elementų mazgas. Mazgas įrengiamas naudojant plienines detales, suvirintas iš lakštinio plieno, kurios inkaruojamos medienos elementuose. Kontaktas tarp medienos ir metalo užtikrinamas ir pradinis mazgo slankumas panaikinamas užpildant tarpus tarp medienos ir metalo užpildu. Pasirinkti du skirtingo pagrindo (sudėties) užpildai: dviejų komponentų poliuretano ir cementinis, kurio sudėtyje yra polimerinių plaušų. Nustatytas cementinio užpildo lekiamasis ir gniuždomasis stipriai. Eksperimentinės jungčių laikomosios galios palyginamos su teoriniais skaičiavimais pagal Lietuvos ir Europos medinių konstrukcijų projektavimo normas. Pateikiamos išvados ir rekomendacijos tolesniems tyrimams.
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Zeng, Fankui, Guoxin Zou, Meng Ji, and Jianhua Zhang. "Study on Semi-Rigid Joint Performance and Stability Bearing Capacity of Disc-Type Steel Pipe Support." Buildings 15, no. 11 (2025): 1955. https://doi.org/10.3390/buildings15111955.
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The current lack of standardized calculation methods for disc-buckle-type steel pipe supports, coupled with unsafe calculation length coefficients, has resulted in frequent safety incidents leading to severe casualties and economic losses. In this paper, the semi-rigidity characteristics of joints were investigated through the field bending test of disc-buckle steel pipe supports. Through analysis of the bending moment–rotation curves obtained from these tests, accurate initial bending stiffness values and a calculation model for semi-rigid joints were established. Numerical simulation and analytical correction method were employed to determine the effective length correction coefficient μ0 under various erection parameters while accounting for joint semi-rigidity. The findings indicate that the slenderness ratio derived by the revised effective length coefficient is 8.13% greater than the standard value, primarily because current standards fail to adequately consider the constraint effect of the crossbar. The correction coefficient proposed in this paper provides a theoretical foundation for the safe construction of disc-type steel pipe supports, and holds significant value for engineering applications.
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Yuan, Pu, and Jun Wen Huang. "Field Experiment Study of the Semi-Rigid Base on Port Reinforced with Glass Fiber Geogrid." Advanced Materials Research 1004-1005 (August 2014): 1468–73. http://dx.doi.org/10.4028/www.scientific.net/amr.1004-1005.1468.
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The pavement and storage yard on port is located in depth soft soil foundation, the settlement is large, so that the approach of enhancing the bearing ability of the pavement and storage yard on port is advanced. Field Experiment of test section which satisfied with the field test methods was carried out. Resilient modulus was determined by the bearing plate method, the pavement base on port engineering reinforced with glass fiber geogrid was analyzed.The test result shows that the effect on the base on port engineering reinforced with glass fiber geogrid is satisfied, the ratio reaches 12% .In addition, the effect of the position reinforced with glass fiber geogrid is different, the better effect of reinforcement with glass fiber geogrid is the toper of the base on port. On this basis,the appoarch of the base on port reinforced with glass fiber geogrid is reference on design and contruction.
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Dong, Jiang Hui, Xing Ma, Julie E. Mills, and Zhu Ge Yan. "A Review of Skin Buckling Theory in Composite Members." Applied Mechanics and Materials 846 (July 2016): 312–17. http://dx.doi.org/10.4028/www.scientific.net/amm.846.312.
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This paper provides a comprehensive review of various methods used for skin buckling analysis in composite components. The skin buckling phenomenon is one of the governing criteria in composite design. It is a kind of contact buckling in which partial sections of skin buckle away from the filler material. In general, the problem can be modelled as a thin plate (skin) in unilateral contact with elastic medium (filler material). The theoretical analysis of contact buckling is complicated due to the nonlinearity arising from changing contact regions. To simplify the calculations, the filler material was usually modelled as a tensionless elastic foundation. The skin buckling coefficient varies in terms of the relative foundation stiffness factors. Because the Eigen-value method is not applicable to nonlinear systems, the finite element (FE) method was usually employed for post-buckling analysis, while initial buckling performance was investigated through analytical or semi-analytical methods such as rigid foundation model, infinite plate model and finite plate model. The compressive buckling and shear buckling problems for thin plates resting on tensionless foundations have been solved successfully. However, there are still urgent needs for future research on the topic. For example, the load carrying capacity of the buckling plates needs to be formulated for practical application. Complicated problems with complex loadings and/or corrugated skins need further investigation as well.
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Molina-Villegas, Juan Camilo, Jorge Eliecer Ballesteros Ortega, and David Ruiz Cardona. "Formulation of the Green’s functions stiffness method for Euler–Bernoulli beams on elastic Winkler foundation with semi-rigid connections." Engineering Structures 266 (September 2022): 114616. http://dx.doi.org/10.1016/j.engstruct.2022.114616.
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Quinn, S., S. S. J. Moy, and Keith Piggott. "Combined Lifting Analysis and Load Test of a Hook Foundation in a GRP Hull." Applied Mechanics and Materials 5-6 (October 2006): 101–6. http://dx.doi.org/10.4028/www.scientific.net/amm.5-6.101.
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The combination of simulation and physical testing is powerful. In this case study Finite Element Analysis (FEA) and a 96 tonne load test were used to prove that the lifting points for a new semi-rigid inflatable rescue craft met their statutory requirements before full manufacture. The FEA was used to optimise the detailed design of the lifting points, without the need to test each different configuration, and the load test was used to prove the final design in practice, before full manufacture. The FEA showed that the bearing stresses in the Glass Reinforced Polymer (GRP) hull of the initial design were unacceptable and appropriate design changes were made from further analysis. However, to suitably risk manage the project a full load test was required to demonstrate that the revised lifting point details met their statutory requirements, before full manufacture of the new craft.
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Yang, Shuli, Zhizhong Cheng, Shouzhi Ren, and Jingya Ma. "Research on the Characteristics of Braided String Based on Domestic Aramid Fiber for Semi-rigid Substrate of Solar Array." Journal of Physics: Conference Series 2920, no. 1 (2024): 012033. https://doi.org/10.1088/1742-6596/2920/1/012033.
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Abstract The substrate serves as a mounting base for the solar cells of the space-based solar array, and the “rigid frame of carbon fiber composite + tensioned mesh structure based on the braided string” constitutes the primary structure of the semi-rigid substrate of the large DFH-5 satellite. Tests and experiments have been conducted in four key areas: the creep characteristics of the braided string and its core under different loads, the creep characteristics of the braided string’s core due to changes in humidity and temperature, and the creep characteristics of the braided string itself due to temperature changes. The results show that the elongation of the braided string is twice that of its core under the same load. To reduce the stress relaxation of the tensioned braided string, it is necessary to perform pre-treatment to mitigate creep in advance. An increase in humidity can cause tension relaxation in the tensioned braided string. To mitigate this, a pre-tensioned core of the braided string can be utilized, and environmental control on the ground is recommended to reduce the impact of humidity on tension relaxation. Thermal pre-treatment is advised, as high temperatures can lead to partial changes in the properties or thermal stress release of aramid III fiber, resulting in the relaxation of the tensioned braided string and irreversible changes. The creep performance of the braided string’s core, however, is not affected by low temperatures. Through these experiments, the creep characteristics and pre-treatment guidelines for the braided string under different environmental conditions have been established, providing a foundation for the large-scale application of this structure in semi-rigid substrates of solar arrays.
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Su, Li Ya. "Mechanics Analysis of Flexible Base Pavement Structure." Applied Mechanics and Materials 580-583 (July 2014): 632–35. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.632.
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With the rapid development of traffic cause in our country, the operating requirement of driving load factors to pavement structure become higher and higher. The Semi-rigid base asphalt pavement structure exposed some defects and shortcomings, so the study of flexible base asphalt pavement structure is put on the agenda under the circumstances.Based on the research achievements at home and abroad of the existing asphalt pavement structure , choosing different elastic modulus and thickness to calculate and analyze the flexible base by ANSYS, gaining the law and trend of mechanics response (the vertical displacement and tensile stress) about pavement structure for the flexible base pavement of each layer foundation to provide the design reference.
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Oetomo, James J., and Ade Restu Permana Putra. "Heave Analysis of Unreinforced Inclusion Column in Low Sensitivity Soft Clay." IOP Conference Series: Earth and Environmental Science 1249, no. 1 (2023): 012037. http://dx.doi.org/10.1088/1755-1315/1249/1/012037.
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Abstract The ground improvement technique with inclusions, is now widely available and used in Indonesia. Typically, it uses unreinforced concrete/mortar columns, commonly referred as rigid inclusions, for enhancing the composite ground engineering properties. Using this approach, the applied load will be distributed to both the rigid inclusions and in-situ soft soil. On the surface, this technique is analogue to compression-only cast-in-situ deep foundation element (i.e., bored pile), but with different design concept. Nonetheless, when these inclusions are installed in clay soil, either with displacement or semi-displacement method, the installed inclusions may experience heave (similar like driven pile), which is caused by ground deformation in the vicinity of installed inclusions. As these inclusions are not reinforced, mobilizing upward skin friction from excessive heave may develop into an integrity issue, specifically, when the mobilized upward force is larger than the inclusion tensile capacity. This study shows an observed heave on unreinforced inclusion columns. Retrospective soil heave prediction using shallow strain path method (SSPM), is presented. Proposed recommendations for avoiding such issue are discussed.
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Mansouri, Saman, and Amin Nazari. "The Effects of Using Different Seismic Bearing on the Behavior and Seismic Response of High-Rise Building." Civil Engineering Journal 3, no. 3 (2017): 160–71. http://dx.doi.org/10.28991/cej-2017-00000082.
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The effects of using different seismic bearings were investigated to reduce the seismic response of buildings by assuming the vulnerability of 20-story regular RC building in this paper. The method of this study was that the studied building was studied in three different models in terms of its connection to the foundation. In the first model, the structures were placed on the rigid bearing and in the second and third models; lead-rubber bearings and friction pendulum bearings were placed at the counter between the structure and foundation, respectively. Then, the dynamic analysis was used to assess the behaviour and seismic response of the mentioned models. The results of the study showed that the structures in the first model functioned like cantilever column that would become uniaxial and biaxial bending under the effects of earthquake around the vertical axis of structure. Due to the tensile (tension) weakness in concrete, seismic loads caused major cracks in the tension part of the structures according to the place of the neutral axis that could lead to the collapse of structure. In addition, the use of mentioned seismic bearings under the earthquake caused the structure like a semi-rigid box slid on this equipment that reduced the structure's stiffness and increased the period of the structure in comparison with the first model. Using the studied seismic bearings caused the displacement of the roof of the first and twentieth stories of the structure become approximately equal and prevented the creation of the bending moment in the first model. The results of non-linear time history analysis showed that using the studied seismic bearings caused the response of the structure reduced significantly when the structure was placed on rigid bearings. It could be very valuable regarding the limitation of the capacity of the structure's members.
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Dai, Guoliang, Haoran OuYang, Luchao Gao, Qing Guo, and Weiming Gong. "Experimental study on monotonic and cyclic lateral behavior enhancing mechanism of semi-rigid pile under different foundation reinforced methods in clay." Ocean Engineering 273 (April 2023): 113955. http://dx.doi.org/10.1016/j.oceaneng.2023.113955.
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Jawad, Hala Mahmood, and Zuhair Kadhim Jahanger. "Collapse Pattern in Gypseous Soil using Particle Image Velocimetry." IOP Conference Series: Earth and Environmental Science 1374, no. 1 (2024): 012012. http://dx.doi.org/10.1088/1755-1315/1374/1/012012.
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Abstract Gypseous soil is prevalent in arid and semi-arid areas, is from collapsible soil, which contains the mineral gypsum, and has variable properties, including moisture-induced volume changes and solubility. Construction on these soils necessitates meticulous assessment and unique designs due to the possibility of foundation damage from soil collapse. The stability and durability of structures situated on gypseous soils necessitate close collaboration with specialists and careful, methodical preparation. It had not been done to find the pattern of failure in the micromechanical behavior of gypseous sandy soil through particle image velocity (PIV) analysis. This adopted recently in geotechnical engineering to track the motion of soil grains and using tracer particles by applying digital particle image analysis. It has also been used to study the displacement distribution in some cases of granular materials. Therefore, the goal of this study is to find out how gypseous sand medium moves when in contact with a rigid strip foundation that is under static stress and plane strain conditions. The experimental model would focus on two common types of wetting, namely water table rise and dry conditions. The PIV showed that the collapse pattern under the footing is of the type of punching shear failure. The predominant mechanism of soil deformation was the vertical compression of the gypseous granular soil. The results showed that understanding gypseous sandy grain displacement and failure patterns at the local scale is crucial for enhancing the design of foundations under static stress conditions.
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Halim, Ridwan, and Sofia Alisjahbana. "PERILAKU DINAMIK PELAT PERKERASAN KAKU AKIBAT BEBAN BERGERAK DENGAN KECEPATAN TIDAK KONSTAN." Jurnal Muara Sains, Teknologi, Kedokteran dan Ilmu Kesehatan 4, no. 1 (2020): 115. http://dx.doi.org/10.24912/jmstkik.v4i1.2287.
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Structural hard structures are often found in industrial buildings, especially in road structures. Most of the vehicles that pass on this road are heavy vehicles such as trucks with heavy loads. So, the engineer must design precisely so that this structure can meet the requirements of strength and deflection. The dynamic analysis of rigid pavement in this thesis is modeled as a concrete slab with boundary conditions all the edges of the slab have a semi rigid footing and on top of the soil media with a Pasternak foundation model that has elastic vertical spring support and a continuous sliding layer underneath. Transverse load that crosses the surface of the plate in the form of a dynamic load that has a initial speed and fixed acceleration. The load is modeled as a single axis centered load equivalent to variations in vehicle types such as: Colt Diesel Double (CDD) Los Bak, Colt Diesel Double (CDD) Long Box, and Colt Diesel Double (CDD) Body. In this study, various types of parameters will be analyzed, including the coefficient of the vehicle, the value of the damping ratio (damping ratio), and various supporting soil conditions, namely soft soil, medium soil and hard soil. Solving the plate dynamics problem with semi-rigid conditions using the Modified Bolotin Method (MBM) with the help of two transcendental equations. This dynamic load function solving uses the special properties of the Dirac-delta function. Analysis is carried out when the load is on the plate (0 ≤ t ≤ t0) with the final result obtained is the spectrum response or critical speed of the vehicle and the forces in the form of moments and shear forces. ABSTRAK Struktur perkerasaan kaku banyak dijumpai pada bangunan industrial khususnya pada struktur jalan. Sebagian besar kendaraan yang melintas pada jalan ini adalah kendaraan berat seperti truk dengan beban berat. Jadi, insinyur harus mendesain dengan tepat sehingga struktur ini dapat memenuhi syarat kekuatan maupun lendutan. Analisis dinamik perkerasan kaku dalam tesis ini dimodelkan sebagai pelat beton dengan kondisi batas semua tepi pelat memiliki tumpuan semi rigid dan di atas media tanah dengan model pondasi Pasternak yang memiliki dukungan pegas vertikal elastis dan lapisan geser menerus di bawahnya. Beban transversal yang melintasi permukaan pelat berupa beban dinamik yang memiliki kecepatan awal serta percepatan tetap. Beban dimodelkan sebagai beban terpusat sumbu tunggal ekuivalen dengan variasi jenis kendaraan seperti: Colt Diesel Double (CDD) Los Bak, Colt Diesel Double (CDD) Long Box, dan Colt Diesel Double (CDD) Bak. Dalam penelitian ini juga akan dilakukan analisis berbagai jenis parameter antara lain nilai koefisien kendaraan, nilai ratio redaman (damping ratio), dan berbagai kondisi tanah pendukung yaitu tanah lunak, tanah sedang, dan tanah keras. Penyelesaian masalah dinamika pelat dengan kondisi semi rigid menggunakan Modified Bolotin Method (MBM) dengan bantuan dua persamaan transendental. Pemecahan fungsi beban dinamik ini menggunakan bantuan sifat-sifat khusus fungsi Dirac-delta. Analisis dilakukan ketika beban berada di atas pelat (0 ≤ t ≤ t0) dengan hasil akhir yang didapat adalah respon spektrum atau kecepetan kritis kendaraan serta gaya-gaya dalam berupa momen dan gaya geser.
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Zaitseva, T. I., I. V. Blinova, and A. M. Uzdin. "Dynamics of Welded Rails Gap and Hardness of Rail Base." International Journal of Applied Mechanics and Engineering 25, no. 1 (2020): 236–42. http://dx.doi.org/10.2478/ijame-2020-0015.
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AbstractThe problem of gap estimation for a break of a continuous welded rail is studied. The track is represented as a semi-infinite rod on elastic-based damping. Static and dynamic solutions are obtained. It is shown that during the rail break, the dynamic factor does not exceed 1.5. We derive equations for thermal deformation of the welded rail of jointless track on an elastic foundation in the presence of the insert into the base with another characteristic stiffness. It is shown that the presence of the insertion of up to 20% of the length of the rail, with both large and small stiffness, has a little effect on the stress-strain state (SSS) of the track. The presence of a rigid insert may increase the clearance of an accidental break of the rail, which has a negative effect on traffic safety.
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Ma, Shi Jie, and Xiao Ming Huang. "Response of Perpetual Pavement under Different Axle Heavy Truck." Advanced Materials Research 838-841 (November 2013): 1173–81. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.1173.
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To investigate suitability of the perpetual pavement under ultra-heavy loads, a test road was constructed on expressway in Shandong province of China. There were five pavement structures include semi-rigid asphalt pavement, each was instrumented with gages for measuring the strains of asphalt base layer, the vertical stress of subgrade, temperature of asphalt layers. The analysis of the strain data indicated that the strain values are affected by the temperature, the vehicle load, axle type, and the pavement structure combination. To research the response of different structure, tested different axle and load at different temperature, then different pavement response models were developed that accounts for layer thickness, axles load, pavement temperature and equivalent modulus of pavement foundation. The models provides good references under heavy vehicle loading and China local climate, it will be useful for perpetual pavement design.
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Husain, Iqbal, and Dino Bagnariol. "Design and Performance of Jointless Bridges in Ontario: New Technical and Material Concepts." Transportation Research Record: Journal of the Transportation Research Board 1696, no. 1 (2000): 109–21. http://dx.doi.org/10.3141/1696-14.
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It is well recognized that leaking expansion joints at the ends of bridge decks have led to the premature deterioration of bridge components. The elimination of these maintenance-prone joints not only yields immediate economic benefits but also improves the long-term durability of bridges. In Ontario, Canada, “jointless” bridges have been used for many years. Recently, the use of two main types of these bridges has increased dramatically. The first type is an “integral abutment” bridge that comprises an integral deck and abutment system supported on flexible piles. The approach slabs are also continuous with the deck slab. The flexible foundation allows the anticipated deck movements to take place at the end of the approach slab. Control joint details have been developed to allow movements at this location. The second type is a “semi-integral abutment” bridge that also allows expansion joints to be eliminated from the end of the bridge deck. The approach slabs are continuous with the deck slab, and the abutments are supported on rigid foundations (spread footings). The superstructure is not continuous with the abutments, and conventional bearings are used to allow horizontal movements between the deck and the abutments. A control joint is provided at the end of the approach slab that is detailed to slide in between the wing walls. Some of the design methods and construction details that are used in Ontario for integral and semi-integral abutment bridges are summarized. A review of the actual performance of existing bridges is also presented.
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Ramhormozian, Shahab, George Charles Clifton, Gregory A. MacRae, and Hsen Han Khoo. "The Sliding Hinge Joint: Final Steps towards an Optimum Low Damage Seismic-Resistant Steel System." Key Engineering Materials 763 (February 2018): 751–60. http://dx.doi.org/10.4028/www.scientific.net/kem.763.751.
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The Sliding Hinge Joint with Asymmetric Friction Connectors (SHJ), to give its full name, is a semi-rigid moment resisting joint used between the beams and columns of a moment-resisting steel frame and also at the column base between the column and the ground. It’s performance is intended to be as follows: 1) On completion of construction, rigid under serviceability limit state conditions, 2) During a severe earthquake, allowing controlled rotation between the column and the beam or foundation on designated friction sliding planes within the connection, then 3) Returning to its rigid in-service condition at the end of the severe shaking with the building returning to its pre-earthquake position (self-centering). During its development and proof of concept through large scale testing, the initial results showed that the SHJ as originally designed and detailed performs 1) and 2) very well, but the bolts in the friction sliding planes loose much of their original installed bolt tension during significant sliding, lowering the level at which rotation within the joint will occur post severe earthquake. A concerted research programme of component testing, analytical model development and numerical modelling in recent years has developed solutions to the bolt tension loss issue as well as enhanced the joint’s performance to deliver dependable self-centering capability for the building. This work marks the final steps towards developing an optimum low damage seismic-resisting steel moment frame system. This paper presents key findings from the research work and general recommendations for the optimum performing sliding hinge joint.
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Zhou, Yingjie, Lihua Tan, Zhiliang Yue, Lei Yan, Kaiyu Jiang, and Xiaoying Gou. "The Vertical Behaviors of Dissimilar Pile Composite Foundations over Inclined Bedrock." Buildings 14, no. 2 (2024): 424. http://dx.doi.org/10.3390/buildings14020424.
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Pile composite foundations (PCFs) have been commonly applied in reinforcement engineering to adjust the vertical stiffness of foundations, due to the displacement control design criteria for foundations. PCFs that have dissimilar pile lengths, located over inclined bedrock, have shown significantly different vertical behaviors from PCFs with equal pile lengths, placed over a semi-infinite medium. However, the vertical behaviors of dissimilar PCFs over inclined bedrock cannot be predicted with the current theoretical methods, although they have been widely adopted in engineering. An analytical method is proposed in this investigation to analyze the vertical bearing characteristics of dissimilar PCFs over inclined bedrock. A pile–soil system is decomposed into fictitious piles and extended soil, and then a control equation to determine the axial force along the fictitious piles is established, stemming from the compatibility conditions between them. The vertical behaviors of dissimilar PCFs can be obtained by solving the control equation with iterative procedures, and the equation is verified by two field load tests of single piles from the Honghe bridge and a numerical case. Then, the settlement and load transfer behaviors of 3 × 1 dissimilar PCFs and their influence factors are analyzed, and the results are as follows. (1) Obvious differences can be observed concerning the axial force distribution, settlement w, and load-sharing ratio (LSR) of each pile element for different pile–soil stiffness ratios (Ep/Es). (2) The LSR of pile 1 increases from 0.074 to 0.253 for the rigid pile and from 0.062 to 0.161 for the flexible pile condition when the cushion stiffness Kc changes from 1 × 104 kN/m to 3 × 108 kN/m. The non-dimensional vertical stiffness of the foundation, N0/wdEs, increases from 10.21 to 28.95 for the rigid pile condition and increases from 8.69 to 14.44 for the flexible pile condition, when Kc increases from 1 × 104 kN/m to 4 × 105 kN/m. (3) The neutral layer depth of the pile zn, the average settlement w, and the differential settlement wd of each element head decrease with Kc, and no negative friction zone exists (zn = 0 m) for all the pile elements when Kc> 2 × 105 kN/m. (4) The N0/wdEs decreases with the distance between the pile bottom and the inclined bedrock Δ. For the rigid and flexible pile conditions, the N0/wdEs is 22.16 and 13.48 for Δ = 1 m, and 13.13 and 10.10 for Δ = 8 m. The wd reaches 16.7 mm and 4.0 mm for Δ = 1 m and Δ = 8 m, respectively. (5) The N0/wdEs increases almost linearly with an increase in l/d for the rigid pile condition, and it gradually decreases for the flexible pile condition. The developed model can improve the design and analysis of PCFs located over inclined bedrock under vertical loading.
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Öner, Erdal. "Computational contact mechanics for a medium consisting of functionally graded material coating and orthotropic substrate." Journal of Structural Engineering & Applied Mechanics 4, no. 4 (2021): 249–66. http://dx.doi.org/10.31462/jseam.2021.04249266.
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This paper presents a semi-analytical method to investigate the frictionless contact mechanics between a functionally graded material (FGM) coating and an orthotropic substrate when the system is indented by a rigid flat punch. From the bottom, the orthotropic substrate is completely bonded to the rigid foundation. The body force of the orthotropic substrate is ignored in the solution, while the body force of the FGM coating is considered. An exponential function is used to define the smooth variation of the shear modulus and density of the FGM coating, and the variation of Poisson’s ratio is assumed to be negligible. The partial differential equation system for the FGM coating and the orthotropic substrate is solved analytically through Fourier transformations. After applying boundary and interface continuity conditions to the mixed boundary value problem, the contact problem is reduced to a singular integral equation. The Gauss–Chebyshev integration method is then used to convert the singular integral equation into a system of linear equations, which are solved using an appropriate iterative algorithm to calculate the contact stress under the rigid flat punch. The parametric analyses presented here demonstrate the effects of normalized punch length, material inhomogeneity, dimensionless press force, and orthotropic material type on contact stresses at interfaces, critical load factor, and initial separation distance between FGM coating and orthotropic substrate. The developed solution procedures are verified through the comparisons made to the results available in the literature. The solution methodology and numerical results presented in this paper can provide some useful guidelines for improving the design of multibody indentation systems using FGMs and anisotropic materials.
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Furqan, M. N., S. W. Alisjahbana, and T. M. Rasyif. "Dynamic Response of Orthotropic Plate Due to Local Friedlander Blast Loads On Kerr Foundation Soil Modeling." IOP Conference Series: Earth and Environmental Science 1347, no. 1 (2024): 012091. http://dx.doi.org/10.1088/1755-1315/1347/1/012091.
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Abstract The development of infrastructure design is getting more advanced, there are more and more things that need to be considered in designing an infrastructure and a building, the effect of blast loads needs to be considered. Explosion load itself is one of the dynamic loads that can burden a structure beyond its normal loading conditions. Therefore, it is necessary to have special planning for an infrastructure and building so that if an explosion occurs it can minimize serious damage to the structure of the infrastructure and building. In this study, the focus is on orthotropic plates with semi-rigid bearings on the Kerr foundation soil model due to local Friedlander blast loads. Variations in plate thickness and soil type were carried out to determine the dynamic response on the plate that would arise due to the local Friedlander blast load. Utilizing the Modified Bolotin Method (MBM) analysis technique to solve it through the Wolfram Mathematica program. Based on the numerical tests that were conducted, it is found that the type of soil is directly proportional to the natural frequency value, indicating that stiffer soil types result in higher natural frequencies, signifying a stiffer response to floor plates. Thicker plates result in smaller deflections with the same soil type. These numerical results can serve as design guidelines for structures under blast loads.
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Ma, Yin Hua, and Jian Yi Gu. "Study on Freeze-Thaw Performance of Polypropylene Fiber Reinforced Cement-Stabilized Aggregate." Advanced Materials Research 446-449 (January 2012): 2595–98. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.2595.
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In this paper, the authors study the anti-freeze-thaw performance of a new type of semi-rigid base material named polypropylene fiber reinforced cement-stabilized aggregate, and freeze-thaw mass loss rate, freeze-thaw compressive strength, freeze-thaw splitting strength are used to evaluate the effect of polypropylene fiber on the anti-freeze-thaw performance, and the relationship of polypropylene fiber content, polypropylene fiber length with the anti-freeze-thaw performance are analyzed. The test after 10 freeze-thaw cycle shows that the mix of polypropylene fiber increase the freeze-thaw compressive strength and freeze-thaw splitting strength, and decrease the mass loss rate greatly. At the same time, the paper also determine the reasonable fiber content and fiber length, under this mix proportion, the mass loss rate reduce by 80%, the freeze-thaw compressive strength increase more than 12.1% and freeze-thaw splitting strength increase more than 13.4%. This research has laid an important foundation for the follow-up research and practice.
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Pushkarenko, Kyle, Janice Causgrove Dunn, and Donna Goodwin. "The Meaning of Physical Literacy for Instructors of Children Experiencing Disability, from an Ecological Systems Perspective." Children 10, no. 7 (2023): 1185. http://dx.doi.org/10.3390/children10071185.
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With the rapid and widespread uptake of physical literacy (PL), there is potential for instructors to devalue participation of children who experience disability. The aim of the investigation was to understand how instructors who facilitate physical activity for children experiencing disability make sense of PL, and more specifically, how these instructors bring meaning to PL. Using interpretive phenomenological analysis, six instructors engaged in individual, semi-structured interviews. The study rationale was underpinned by the conceptual framework of ecological systems theory, which provided a foundation for the research, guided the structure of the interview guide, and facilitated a reflexive interpretation of the findings. Four themes were generated: Recognizing unique embodiments, The importance of context, Beyond physical competence, and Navigating PL’s dominant discourse. The instructors’ meaning of PL, impacted by relational and environmental influences, reflected the importance of movement skill development, while also embracing diverse embodiment and pedagogical flexibility by giving value to exploratory play, partial participation, family involvement, and willingness to abandon rigid lessons plans.
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Amal Hassan Essia and Nagwa Mohammed Khallaf. "Critical Thinking: EFL Teachers' Perceptions and Barriers." Journal of English Language Teaching and Applied Linguistics 7, no. 2 (2025): 240–48. https://doi.org/10.32996/jeltal.2025.7.2.23.
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This study explores the perceptions of English as a Foreign Language (EFL) teachers towards critical thinking and the challenges they face in promoting it while teaching. Critical thinking is increasingly regarded as a vital skill for students in today's complex and fast-changing world. Fostering critical thinking in English as a Foreign Language classroom presents several challenges, including rigid curricula, insufficient teacher training, and cultural constraints. The study adopted a mixed-methods approach combining both qualitative and quantitative research design, both a survey and semi-structured interviews were utilized with sixteen EFL teachers at the Foundation program at Dhofar University in Oman. Findings revealed that while educators recognize the significance of critical thinking skills, they encounter substantial challenges such as limited professional development opportunities, exam-oriented teaching focus, and students’ resistance to engaging in critical thinking activities. The study highlights the urgent need to institutional support, targeted training programs, and curriculum reforms to empower EFL teachers in effectively nurturing critical thinking skills among their EFL learners.
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Habibi, Mahboobe, Giuseppe Sutera, Dario Calogero Guastella, and Giovanni Muscato. "Design and Experimental Validation of a 3D-Printed Two-Finger Gripper with a V-Shaped Profile for Lightweight Waste Collection." Robotics 14, no. 7 (2025): 87. https://doi.org/10.3390/robotics14070087.
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This study presents the design, fabrication, and experimental validation of a two-finger robotic gripper featuring a 135∘ V-shaped fingertip profile tailored for lightweight waste collection in laboratory-scale environmental robotics. The gripper was developed with a strong emphasis on cost-effectiveness and manufacturability, utilizing a desktop 3D printer and off-the-shelf servomotors. A four-bar linkage mechanism enables parallel jaw motion and ensures stable surface contact during grasping, achieving a maximum opening range of 71.5 mm to accommodate common cylindrical objects. To validate structural integrity, finite element analysis (FEA) was conducted under a 0.6 kg load, yielding a safety factor of 3.5 and a peak von Mises stress of 12.75 MPa—well below the material yield limit of PLA. Experimental testing demonstrated grasp success rates of up to 80 percent for typical waste items, including bottles, disposable cups, and plastic bags. While the gripper performs reliably with rigid and semi-rigid objects, further improvements are needed for handling highly deformable materials such as thin films or soft bags. The proposed design offers significant advantages in terms of rapid prototyping (a print time of approximately 10 h), modularity, and low manufacturing cost (with an estimated in-house material cost of USD 20 to 40). It provides a practical and accessible solution for small-scale robotic waste-collection tasks and serves as a foundation for future developments in affordable, application-specific grippers.