Pub Date : 2021-01-01DOI: 10.12989/SEM.2021.79.6.711
M. Farrokh, Mohammad Taheripur
In this paper, the porosity distribution of functionally graded porous (FGP) beams are optimized using the genetic algorithm to achieve the maximum ratio of the normalized buckling load to the beam's weight. The analytical forms for critical buckling loads of the FGP beams under different end conditions are determined analytically using principle virtual work based on the Euler and Timoshenko beam theories. The effects of Nano Graphene Platelets (NGPs) on the critical buckling load of the nanocomposite FGP beams are also taken into account. The sensitivity analyses show that porosity will reduce the buckling load-to-weight ratio of porous beams to conventional beams in some cases. Based on the optimization results, the optimum distribution of the porosity and NGPs' volume fraction are proposed for several porosity coefficients. The obtained results indicate that the optimum distribution for porosity has a symmetric sandwich-like shape while the optimum distribution for NGPs' volume fraction is uniform.
{"title":"Optimization of porosity distribution of FGP beams considering buckling strength","authors":"M. Farrokh, Mohammad Taheripur","doi":"10.12989/SEM.2021.79.6.711","DOIUrl":"https://doi.org/10.12989/SEM.2021.79.6.711","url":null,"abstract":"In this paper, the porosity distribution of functionally graded porous (FGP) beams are optimized using the genetic algorithm to achieve the maximum ratio of the normalized buckling load to the beam's weight. The analytical forms for critical buckling loads of the FGP beams under different end conditions are determined analytically using principle virtual work based on the Euler and Timoshenko beam theories. The effects of Nano Graphene Platelets (NGPs) on the critical buckling load of the nanocomposite FGP beams are also taken into account. The sensitivity analyses show that porosity will reduce the buckling load-to-weight ratio of porous beams to conventional beams in some cases. Based on the optimization results, the optimum distribution of the porosity and NGPs' volume fraction are proposed for several porosity coefficients. The obtained results indicate that the optimum distribution for porosity has a symmetric sandwich-like shape while the optimum distribution for NGPs' volume fraction is uniform.","PeriodicalId":51181,"journal":{"name":"Structural Engineering and Mechanics","volume":"79 1","pages":"711"},"PeriodicalIF":2.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66130902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SEM.2021.79.4.401
M. Rahmani, Y. Mohammadi
In this paper, in various boundary conditions, the vibration behavior of the two types of porous FG truncated conical sandwich shells is investigated based on the improved high order sandwich shells theory. Two types of porosity are considered in the power law rule to model the FGM properties. In the first type, FG face sheets cover a homogeneous core, and in the second one, the FG core is covered by the homogeneous face sheets. All materials are temperature dependent. By utilizing the Hamilton's energy principle, using the nonlinear von Karman strains in the layers and considering the in-plane stresses and thermal stresses in the core and the face sheets, the governing equations are obtained. A Galerkin method is used to solve the equations with clamped-clamped, clamped-free, and free-free boundary conditions. To validate the results, a FEM software is used and some results are validated with the results in the literatures. Also, Some geometrical parameters, temperature variations and porosity effects are studied. By increasing the length to thickness ratio, temperature, the semi-vertex angle and the radius to thickness ratio, the fundamental frequency parameter decreases in all boundary conditions. In both types of sandwiches for both porosity distributions, by increasing the porosity volume fraction, the fundamental frequency parameters increase. Frequency variation of type-II is lower than type-I in the thermal conditions. And the fundamental frequencies of the clamped-clamped (CC) and clamped-free (C-F) boundary conditions have the highest and lowest values, respectively.
{"title":"Vibration of two types of porous FG sandwich conical shellwith different boundary conditions","authors":"M. Rahmani, Y. Mohammadi","doi":"10.12989/SEM.2021.79.4.401","DOIUrl":"https://doi.org/10.12989/SEM.2021.79.4.401","url":null,"abstract":"In this paper, in various boundary conditions, the vibration behavior of the two types of porous FG truncated conical sandwich shells is investigated based on the improved high order sandwich shells theory. Two types of porosity are considered in the power law rule to model the FGM properties. In the first type, FG face sheets cover a homogeneous core, and in the second one, the FG core is covered by the homogeneous face sheets. All materials are temperature dependent. By utilizing the Hamilton's energy principle, using the nonlinear von Karman strains in the layers and considering the in-plane stresses and thermal stresses in the core and the face sheets, the governing equations are obtained. A Galerkin method is used to solve the equations with clamped-clamped, clamped-free, and free-free boundary conditions. To validate the results, a FEM software is used and some results are validated with the results in the literatures. Also, Some geometrical parameters, temperature variations and porosity effects are studied. By increasing the length to thickness ratio, temperature, the semi-vertex angle and the radius to thickness ratio, the fundamental frequency parameter decreases in all boundary conditions. In both types of sandwiches for both porosity distributions, by increasing the porosity volume fraction, the fundamental frequency parameters increase. Frequency variation of type-II is lower than type-I in the thermal conditions. And the fundamental frequencies of the clamped-clamped (CC) and clamped-free (C-F) boundary conditions have the highest and lowest values, respectively.","PeriodicalId":51181,"journal":{"name":"Structural Engineering and Mechanics","volume":"79 1","pages":"401"},"PeriodicalIF":2.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66129072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SEM.2021.79.5.565
Bo Yu, Zihao Ding, S. Liu, Bing Li
In order to predict the shear strength of corroded reinforced concrete column (CRCC) accurately and efficiently, both theoretical and practical models for shear strength of the CRCC were established through theoretical derivation and experimental validation. The deterioration mechanism for shear strength of the CRCC due to the steel reinforcement corrosion was explored first based on the shear mechanism analysis of the truss-arch model. Then a theoretical model for shear strength of the CRCC was developed by taking into account the influences of steel reinforcement corrosion on the effective yield strength of transverse reinforcement, the effective cross-sectional area of both corroded transverse and longitudinal reinforcements as well as the effective concrete shear area. Meanwhile, three practical models to evaluate the shear strength of the CRCC were proposed based on 54 sets of experimental data by determining the approximate values of three important parameters, including the contribution coefficient of shear strength for concrete, the ratio of shear stiffness between the truss model and the arch model, as well as the tangent value of the critical crack angle. Finally, the accuracy and applicability of both theoretical and practical models for shear strength of the CRCC were validated by comparing with five existing empirical shear strength models.
{"title":"Theoretical and practical models for shear strength of corroded reinforced concrete columns","authors":"Bo Yu, Zihao Ding, S. Liu, Bing Li","doi":"10.12989/SEM.2021.79.5.565","DOIUrl":"https://doi.org/10.12989/SEM.2021.79.5.565","url":null,"abstract":"In order to predict the shear strength of corroded reinforced concrete column (CRCC) accurately and efficiently, both theoretical and practical models for shear strength of the CRCC were established through theoretical derivation and experimental validation. The deterioration mechanism for shear strength of the CRCC due to the steel reinforcement corrosion was explored first based on the shear mechanism analysis of the truss-arch model. Then a theoretical model for shear strength of the CRCC was developed by taking into account the influences of steel reinforcement corrosion on the effective yield strength of transverse reinforcement, the effective cross-sectional area of both corroded transverse and longitudinal reinforcements as well as the effective concrete shear area. Meanwhile, three practical models to evaluate the shear strength of the CRCC were proposed based on 54 sets of experimental data by determining the approximate values of three important parameters, including the contribution coefficient of shear strength for concrete, the ratio of shear stiffness between the truss model and the arch model, as well as the tangent value of the critical crack angle. Finally, the accuracy and applicability of both theoretical and practical models for shear strength of the CRCC were validated by comparing with five existing empirical shear strength models.","PeriodicalId":51181,"journal":{"name":"Structural Engineering and Mechanics","volume":"79 1","pages":"565-578"},"PeriodicalIF":2.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66129877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SEM.2021.79.5.541
Danilo D’Angela, M. Ercolino
The paper presents innovative approaches for the simulation of fatigue crack growth (FCG) in metallic compact tension (CT) specimens using finite element (FE) analysis and analytical solution. FE analysis is performed in ABAQUS using the extended finite element method (XFEM) coupled with the direct cyclic low-cycle fatigue (LCF) approach. Novel methods are developed for the computation of the numerical crack growth by processing the analysis outputs. The numerical modelling is validated by considering past experimental data. The analytical solution for the fatigue life evaluation is formally reviewed, and novel fatigue damage descriptors are defined. The influence of the main sample/testing features on numerical and analytical fatigue life is extensively assessed by a parametric study. The discrepancy between the numerical and analytical estimations of the fatigue life of the components is investigated and correlated to the features of the testing/modelling. A statistical-based correction factor is finally proposed in order to enhance the analytical solution.
{"title":"Fatigue crack growth in metallic components: Numerical modelling and analytical solution","authors":"Danilo D’Angela, M. Ercolino","doi":"10.12989/SEM.2021.79.5.541","DOIUrl":"https://doi.org/10.12989/SEM.2021.79.5.541","url":null,"abstract":"The paper presents innovative approaches for the simulation of fatigue crack growth (FCG) in metallic compact tension (CT) specimens using finite element (FE) analysis and analytical solution. FE analysis is performed in ABAQUS using the extended finite element method (XFEM) coupled with the direct cyclic low-cycle fatigue (LCF) approach. Novel methods are developed for the computation of the numerical crack growth by processing the analysis outputs. The numerical modelling is validated by considering past experimental data. The analytical solution for the fatigue life evaluation is formally reviewed, and novel fatigue damage descriptors are defined. The influence of the main sample/testing features on numerical and analytical fatigue life is extensively assessed by a parametric study. The discrepancy between the numerical and analytical estimations of the fatigue life of the components is investigated and correlated to the features of the testing/modelling. A statistical-based correction factor is finally proposed in order to enhance the analytical solution.","PeriodicalId":51181,"journal":{"name":"Structural Engineering and Mechanics","volume":"79 1","pages":"541"},"PeriodicalIF":2.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66129951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SEM.2021.79.6.699
Hao Qiu, Jinshan Huang, Zhupeng Zheng
It is necessary to identify structures with unknown mass and unknown seismic excitations simultaneously, but very limited methods have been proposed. In this paper, an algorithm is proposed to identify structural element mass, stiffness, and seismic excitations using only partial absolute structural responses of chain-like systems. In the first stage, the identification of structural element stiffness-mass coupled coefficients and unknown seismic excitations is conducted based on the generalized extended Kalman filter with unknown input (GEKF-UI) developed by the authors. In the second stage, these coupled coefficients are decoupled by cluster analysis and the least squares estimation (LSE) to obtain structural element stiffness and mass changes. The effectiveness of the proposed algorithm is numerically investigated using a four-story frame structure under three scenarios of changed conditions. Moreover, experimental validation by the shaking table test of a shear structure under two scenarios is also performed to identify structures and seismic excitations simultaneously.
{"title":"Simultaneous Identification of structures and unknown seismic excitations for chain-like systems with unknown mass using partial absolute responses","authors":"Hao Qiu, Jinshan Huang, Zhupeng Zheng","doi":"10.12989/SEM.2021.79.6.699","DOIUrl":"https://doi.org/10.12989/SEM.2021.79.6.699","url":null,"abstract":"It is necessary to identify structures with unknown mass and unknown seismic excitations simultaneously, but very limited methods have been proposed. In this paper, an algorithm is proposed to identify structural element mass, stiffness, and seismic excitations using only partial absolute structural responses of chain-like systems. In the first stage, the identification of structural element stiffness-mass coupled coefficients and unknown seismic excitations is conducted based on the generalized extended Kalman filter with unknown input (GEKF-UI) developed by the authors. In the second stage, these coupled coefficients are decoupled by cluster analysis and the least squares estimation (LSE) to obtain structural element stiffness and mass changes. The effectiveness of the proposed algorithm is numerically investigated using a four-story frame structure under three scenarios of changed conditions. Moreover, experimental validation by the shaking table test of a shear structure under two scenarios is also performed to identify structures and seismic excitations simultaneously.","PeriodicalId":51181,"journal":{"name":"Structural Engineering and Mechanics","volume":"79 1","pages":"699-709"},"PeriodicalIF":2.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66130603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SEM.2021.79.6.749
Ömer Mercimek, Ö. Anıl, Rahim Ghoroubi, S. Sakin, T. Yılmaz
{"title":"Experimental and numerical investigation of RC column strengthening with CFRP strips subjected to low-velocity impact load","authors":"Ömer Mercimek, Ö. Anıl, Rahim Ghoroubi, S. Sakin, T. Yılmaz","doi":"10.12989/SEM.2021.79.6.749","DOIUrl":"https://doi.org/10.12989/SEM.2021.79.6.749","url":null,"abstract":"","PeriodicalId":51181,"journal":{"name":"Structural Engineering and Mechanics","volume":"79 1","pages":"749-765"},"PeriodicalIF":2.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66130700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SEM.2021.80.1.015
Juncai Liu, Liqiang Tian, R. Ma, Bingian Zhang, Aiqiang Xin
This paper aims to provide a comprehensive performance assessment of a latticed tension-type transmission tower by performing both full-scale static tests and numerical simulations. In particular, a full-scale tension-type transmission tower was firstly constructed and tested for examining the performances under design loads and the ultimate capacity under an extreme wind load. The displacement and strain responses are investigated, and the failure process of the tension-type tower is presented. Numerical simulations are then performed in order to capture the failure process and estimate the bearing capacity of the experimental tower under the overload case. Moreover, Numerical simulations are also adopted to evaluate the influence of wind attack angles on the structural behavior of the tested tower. Experimental and numerical results demonstrate that this latticed tension-type transmission tower is designed with sufficient capacity to resist the design loads, and the buckling failures of the leg members at the bottom are the governing reason for the collapse of tower. In addition, the developed numerical model can accurately present the failure and structural response of the tension-type tower, and the influence of wind attack angles on the structural behavior is significant. This research is beneficial for improving the understanding on the bearing capacity and design of latticed tension-type transmission towers.
{"title":"Performance assessment and collapse prediction of a latticed tension-type transmission tower","authors":"Juncai Liu, Liqiang Tian, R. Ma, Bingian Zhang, Aiqiang Xin","doi":"10.12989/SEM.2021.80.1.015","DOIUrl":"https://doi.org/10.12989/SEM.2021.80.1.015","url":null,"abstract":"This paper aims to provide a comprehensive performance assessment of a latticed tension-type transmission tower by performing both full-scale static tests and numerical simulations. In particular, a full-scale tension-type transmission tower was firstly constructed and tested for examining the performances under design loads and the ultimate capacity under an extreme wind load. The displacement and strain responses are investigated, and the failure process of the tension-type tower is presented. Numerical simulations are then performed in order to capture the failure process and estimate the bearing capacity of the experimental tower under the overload case. Moreover, Numerical simulations are also adopted to evaluate the influence of wind attack angles on the structural behavior of the tested tower. Experimental and numerical results demonstrate that this latticed tension-type transmission tower is designed with sufficient capacity to resist the design loads, and the buckling failures of the leg members at the bottom are the governing reason for the collapse of tower. In addition, the developed numerical model can accurately present the failure and structural response of the tension-type tower, and the influence of wind attack angles on the structural behavior is significant. This research is beneficial for improving the understanding on the bearing capacity and design of latticed tension-type transmission towers.","PeriodicalId":51181,"journal":{"name":"Structural Engineering and Mechanics","volume":"80 1","pages":"15"},"PeriodicalIF":2.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66130941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SEM.2021.77.1.001
M. Bonopera, Kuo-Chun Chang, Tzu-Kang Lin, N. Tullini
The influence of prestress force on the fundamental frequency and static deflection shape of uncracked Prestressed Concrete (PC) beams with a parabolic bonded tendon was examined in this paper. Due to the conflicts among existing theories, the analytical solutions for properly considering the dynamic and static behavior of these members is not straightforward. A series of experiments were conducted for a total period of approximately 2.5 months on a PC beam made with high strength concrete, subsequently and closely to the 28 days of age of concrete. Specifically, the simply supported PC member was short term subjected to free transverse vibration and three-point bending tests during its early-age. Subsequently, the experimental data were compared with a model that describes the dynamic behavior of PC girders as a combination of two substructures interconnected, i.e., a compressed Euler–Bernoulli beam and a tensioned parabolic cable. It was established that the fundamental frequency of uncracked PC beams with a parabolic bonded tendon is sensitive to the variation of the initial elastic modulus of concrete in the early-age curing. Furthermore, the small variation in experimental frequency with time makes doubtful its use in inverse problem identifications. Conversely, the relationship between prestress force and static deflection shape is well described by the magnification factor formula of the “compression-softening” theory by assuming the variation of the chord elastic modulus of concrete with time.
{"title":"Influence of prestressing on the behavior of uncracked concrete beams with a parabolic bonded tendon","authors":"M. Bonopera, Kuo-Chun Chang, Tzu-Kang Lin, N. Tullini","doi":"10.12989/SEM.2021.77.1.001","DOIUrl":"https://doi.org/10.12989/SEM.2021.77.1.001","url":null,"abstract":"The influence of prestress force on the fundamental frequency and static deflection shape of uncracked Prestressed Concrete (PC) beams with a parabolic bonded tendon was examined in this paper. Due to the conflicts among existing theories, the analytical solutions for properly considering the dynamic and static behavior of these members is not straightforward. A series of experiments were conducted for a total period of approximately 2.5 months on a PC beam made with high strength concrete, subsequently and closely to the 28 days of age of concrete. Specifically, the simply supported PC member was short term subjected to free transverse vibration and three-point bending tests during its early-age. Subsequently, the experimental data were compared with a model that describes the dynamic behavior of PC girders as a combination of two substructures interconnected, i.e., a compressed Euler–Bernoulli beam and a tensioned parabolic cable. It was established that the fundamental frequency of uncracked PC beams with a parabolic bonded tendon is sensitive to the variation of the initial elastic modulus of concrete in the early-age curing. Furthermore, the small variation in experimental frequency with time makes doubtful its use in inverse problem identifications. Conversely, the relationship between prestress force and static deflection shape is well described by the magnification factor formula of the “compression-softening” theory by assuming the variation of the chord elastic modulus of concrete with time.","PeriodicalId":51181,"journal":{"name":"Structural Engineering and Mechanics","volume":"77 1","pages":"1-17"},"PeriodicalIF":2.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66119988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SEM.2021.77.2.261
Q. Lin, Sheng-cai Li, Yongfu Zhu
The energy-saving block and invisible multi-ribbed frame composite wall (EBIMFCW) is a new type of load-bearing wall. The study of this paper focus on it is hysteresis rule under horizontal cyclic loading. Firstly, based on the experimental data of the twelve specimens under horizontal cyclic loading, the influence of two important parameters of axial compression ratio and shear-span ratio on the restoring force model was analyzed. Secondly, a tetra-linear restoring force model considering four feature points and the degradation law of unloading stiffness was established by combining theoretical analysis and regression analysis of experimental data, and the theoretical formula of the peak load of the EBIMFCW was derived. Finally, the hysteretic path of the restoring force model was determined by analyzing the hysteresis characteristics of the typical hysteresis loop. The results show that the curves calculated by the tetra-linear restoring force model in this paper agree well with the experimental curves, especially the calculated values of the peak load of the wall are very close to the experimental values, which can provide a reference for the elastic-plastic analysis of the EBIMFCW.
{"title":"Analysis of hysteresis rule of energy-saving block and invisible multi-ribbed frame composite wall","authors":"Q. Lin, Sheng-cai Li, Yongfu Zhu","doi":"10.12989/SEM.2021.77.2.261","DOIUrl":"https://doi.org/10.12989/SEM.2021.77.2.261","url":null,"abstract":"The energy-saving block and invisible multi-ribbed frame composite wall (EBIMFCW) is a new type of load-bearing wall. The study of this paper focus on it is hysteresis rule under horizontal cyclic loading. Firstly, based on the experimental data of the twelve specimens under horizontal cyclic loading, the influence of two important parameters of axial compression ratio and shear-span ratio on the restoring force model was analyzed. Secondly, a tetra-linear restoring force model considering four feature points and the degradation law of unloading stiffness was established by combining theoretical analysis and regression analysis of experimental data, and the theoretical formula of the peak load of the EBIMFCW was derived. Finally, the hysteretic path of the restoring force model was determined by analyzing the hysteresis characteristics of the typical hysteresis loop. The results show that the curves calculated by the tetra-linear restoring force model in this paper agree well with the experimental curves, especially the calculated values of the peak load of the wall are very close to the experimental values, which can provide a reference for the elastic-plastic analysis of the EBIMFCW.","PeriodicalId":51181,"journal":{"name":"Structural Engineering and Mechanics","volume":"77 1","pages":"261-272"},"PeriodicalIF":2.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66121120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SEM.2021.77.4.481
H. Kakolvand, M. Ghazi, B. Mehrparvar, S. Parvizi
Low rise masonry structures are relatively inexpensive and easier to construct compared to other types of structures such as steel and reinforced concrete buildings. However, masonry structures are relatively heavier and less ductile and more vulnerable to damages in earthquakes. In this research, a new innovative low-cost seismic isolator using steel rings (SISR) is employed to reduce the seismic vulnerability of masonry structures. FEA of a masonry structure, made of concrete blocks is used to evaluate the effect of the proposed SISR on the seismic response of the structure. Two systems, fixed base and isolated from the base with the proposed SISRs, are considered. Micro-element approach and ABAQUS software are used for structural modeling. The nonlinear structural parameters of the SISRs, extracted from a recent experimental study by the authors, are used in numerical modeling. The masonry structure is studied in two separate modes, fixed base and isolated base with the proposed SISRs, under Erzincan and Imperial Valley-06 earthquakes. The accelerated response at the roof level, as well as the deformation in the masonry walls, are the parameters to assess the effect of the proposed SISRs. The results show a highly improved performance of the masonry structure with the SISRs.
{"title":"Evaluation of a new proposed seismic isolator for low rise masonry structures","authors":"H. Kakolvand, M. Ghazi, B. Mehrparvar, S. Parvizi","doi":"10.12989/SEM.2021.77.4.481","DOIUrl":"https://doi.org/10.12989/SEM.2021.77.4.481","url":null,"abstract":"Low rise masonry structures are relatively inexpensive and easier to construct compared to other types of structures such as steel and reinforced concrete buildings. However, masonry structures are relatively heavier and less ductile and more vulnerable to damages in earthquakes. In this research, a new innovative low-cost seismic isolator using steel rings (SISR) is employed to reduce the seismic vulnerability of masonry structures. FEA of a masonry structure, made of concrete blocks is used to evaluate the effect of the proposed SISR on the seismic response of the structure. Two systems, fixed base and isolated from the base with the proposed SISRs, are considered. Micro-element approach and ABAQUS software are used for structural modeling. The nonlinear structural parameters of the SISRs, extracted from a recent experimental study by the authors, are used in numerical modeling. The masonry structure is studied in two separate modes, fixed base and isolated base with the proposed SISRs, under Erzincan and Imperial Valley-06 earthquakes. The accelerated response at the roof level, as well as the deformation in the masonry walls, are the parameters to assess the effect of the proposed SISRs. The results show a highly improved performance of the masonry structure with the SISRs.","PeriodicalId":51181,"journal":{"name":"Structural Engineering and Mechanics","volume":"77 1","pages":"481-493"},"PeriodicalIF":2.2,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66121660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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