A reliable seismic-resistant design of structures is achieved in accordance with the seismic design codes by designing structures under seven or more pairs of earthquake records. Based on the recommendations of seismi...A reliable seismic-resistant design of structures is achieved in accordance with the seismic design codes by designing structures under seven or more pairs of earthquake records. Based on the recommendations of seismic design codes, the average time-history responses （ATHR） of structure is required. This paper focuses on the optimal seismic design of reinforced concrete （RC） structures against ten earthquake records using a hybrid of particle swarm optimization algorithm and an intelligent regression model （IRM）. In order to reduce the computational time of optimization procedure due to the computational efforts of time-history analyses, IRM is proposed to accurately predict ATHR of structures. The proposed IRM consists of the combination of the subtractive algorithm （SA）, K-means clustering approach and wavelet weighted least squares support vector machine （WWLS-SVM）. To predict ATHR of structures, first, the input-output samples of structures are classified by SA and K-means clustering approach. Then, WWLS-SVM is trained with few samples and high accuracy for each cluster. 9- and 18-storey RC frames are designed optimally to illustrate the effectiveness and practicality of the proposed IRM. The numerical results demonstrate the efficiency and computational advantages of IRM for optimal design of structures subjected to time-history earthquake loads.展开更多
A finite element calculation model of corroded RC eccentric compressive members was build using finite element software ANSYS. The model considers the decline of mechanical properties and the effective section of a co...A finite element calculation model of corroded RC eccentric compressive members was build using finite element software ANSYS. The model considers the decline of mechanical properties and the effective section of a corroded steel bar,as well as the deterioration of bond character between corroded reinforcement and concrete. The reliability of the finite element model was evaluated by comparing the results of the finite element calculation with the data from experiments. Based on the finite element analysis results,the influence of corrosion degree,the diameter change of the longitudinal reinforcing bars and the spacing change of stirrups on the flexural stiffness were calculated and analyzed.展开更多
In recent years, an emerging technology termed high-strength concrete （HSC） has become popular in construction industry. Present study describes an experimental research on the behavior of high-strength concrete bea...In recent years, an emerging technology termed high-strength concrete （HSC） has become popular in construction industry. Present study describes an experimental research on the behavior of high-strength concrete beams in ultimate and service state. Six simply supported beams were tested, by applying comprising two symmetric concentrated loads. Tests are reported in this study on the flexural behavior of high-strength reinforced concrete （HSRC） beams made with coarse and fine aggregate together with Microsilica. Test parameter considered includes effect of being compressive reinforcement. Based on the obtained results, the behavior of such members is more deeply reviewed. Also a comparison between theoretical and experimental results is reported here. The beams were made from concrete having compressive strength of 66.81-77.72 N/mm2 and percentage reinforcement ratio （P/Pb） in the range of 0.56% - 1.20%. The ultimate moment for the tested beams was found to be in a good agreement with that of the predicted ultimate moment based on ACI 318-11, ACI 363 and C SA-04 provisions. The predicted deflection based classical formulation based on code provisions for serviceability requirements is found to underestimate the maximum deflection of HSC reinforced beams at service load.展开更多
Over the past several decades,a variety of technical ways have been developed in seismic retrofitting of existing reinforced concrete frames(RFs).Among them,pin-supported rocking walls(PWs)have received much attention...Over the past several decades,a variety of technical ways have been developed in seismic retrofitting of existing reinforced concrete frames(RFs).Among them,pin-supported rocking walls(PWs)have received much attentions to researchers recently.However,it is still a challenge that how to determine the stiffness demand of PWs and assign the value of the drift concentration factor(DCF)for entire systems rationally and efficiently.In this paper,a design method has been exploited for seismic retrofitting of existing RFs using PWs(RF-PWs)via a multi-objective evolutionary algorithm.Then,the method has been investigated and verified through a practical project.Finally,a parametric analysis was executed to exhibit the strengths and working mechanism of the multi-objective design method.To sum up,the findings of this investigation show that the method furnished in this paper is feasible,functional and can provide adequate information for determining the stiffness demand and the value of the DCFfor PWs.Furthermore,it can be applied for the preliminary design of these kinds of structures.展开更多
文摘A reliable seismic-resistant design of structures is achieved in accordance with the seismic design codes by designing structures under seven or more pairs of earthquake records. Based on the recommendations of seismic design codes, the average time-history responses （ATHR） of structure is required. This paper focuses on the optimal seismic design of reinforced concrete （RC） structures against ten earthquake records using a hybrid of particle swarm optimization algorithm and an intelligent regression model （IRM）. In order to reduce the computational time of optimization procedure due to the computational efforts of time-history analyses, IRM is proposed to accurately predict ATHR of structures. The proposed IRM consists of the combination of the subtractive algorithm （SA）, K-means clustering approach and wavelet weighted least squares support vector machine （WWLS-SVM）. To predict ATHR of structures, first, the input-output samples of structures are classified by SA and K-means clustering approach. Then, WWLS-SVM is trained with few samples and high accuracy for each cluster. 9- and 18-storey RC frames are designed optimally to illustrate the effectiveness and practicality of the proposed IRM. The numerical results demonstrate the efficiency and computational advantages of IRM for optimal design of structures subjected to time-history earthquake loads.
基金The National Natural Science Foundation of China (No.50578068)
文摘A finite element calculation model of corroded RC eccentric compressive members was build using finite element software ANSYS. The model considers the decline of mechanical properties and the effective section of a corroded steel bar,as well as the deterioration of bond character between corroded reinforcement and concrete. The reliability of the finite element model was evaluated by comparing the results of the finite element calculation with the data from experiments. Based on the finite element analysis results,the influence of corrosion degree,the diameter change of the longitudinal reinforcing bars and the spacing change of stirrups on the flexural stiffness were calculated and analyzed.
文摘In recent years, an emerging technology termed high-strength concrete （HSC） has become popular in construction industry. Present study describes an experimental research on the behavior of high-strength concrete beams in ultimate and service state. Six simply supported beams were tested, by applying comprising two symmetric concentrated loads. Tests are reported in this study on the flexural behavior of high-strength reinforced concrete （HSRC） beams made with coarse and fine aggregate together with Microsilica. Test parameter considered includes effect of being compressive reinforcement. Based on the obtained results, the behavior of such members is more deeply reviewed. Also a comparison between theoretical and experimental results is reported here. The beams were made from concrete having compressive strength of 66.81-77.72 N/mm2 and percentage reinforcement ratio （P/Pb） in the range of 0.56% - 1.20%. The ultimate moment for the tested beams was found to be in a good agreement with that of the predicted ultimate moment based on ACI 318-11, ACI 363 and C SA-04 provisions. The predicted deflection based classical formulation based on code provisions for serviceability requirements is found to underestimate the maximum deflection of HSC reinforced beams at service load.
基金The authors are grateful for the financial supports from the Scientific Research Fund of Institute of Engineering Mechanics,China Earthquake Administration(Nos.2019D12 and 2019D11)Open Foundation of State Key Laboratory of Disaster Reduction in Civil Engineering,Tongji University in China(No.SLDRCE19-01)+3 种基金Foundation of Public Welfare Technology Research Project of Zhejiang Province in China(No.LGF20E080013)Natural Science Foundation of Zhejiang Province,China(No.LY22E080003)Fundamental Research Fund for the Provincial Universities of Zhejiang(No.SJLZ2022003)Foundation of Public Welfare Technology Research Project of Ningbo in China,(Nos.2022S170,2022S179).
文摘Over the past several decades,a variety of technical ways have been developed in seismic retrofitting of existing reinforced concrete frames(RFs).Among them,pin-supported rocking walls(PWs)have received much attentions to researchers recently.However,it is still a challenge that how to determine the stiffness demand of PWs and assign the value of the drift concentration factor(DCF)for entire systems rationally and efficiently.In this paper,a design method has been exploited for seismic retrofitting of existing RFs using PWs(RF-PWs)via a multi-objective evolutionary algorithm.Then,the method has been investigated and verified through a practical project.Finally,a parametric analysis was executed to exhibit the strengths and working mechanism of the multi-objective design method.To sum up,the findings of this investigation show that the method furnished in this paper is feasible,functional and can provide adequate information for determining the stiffness demand and the value of the DCFfor PWs.Furthermore,it can be applied for the preliminary design of these kinds of structures.
