检索结果-南通市图书馆

Earthquake engineering and engineering Vibration 2015年第1期14卷 97-109页

作者： Sadjad Gharehbaghi Mohsen Khatibinia department of civil engineering Behbahan Khatam Alanbia University of Technology department of civil engineering University of Birjand

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.

关键词： optimal seismic design reinforced concrete frames earthquake loads particle swarm optimization intelligent regression model support vector machine

Deflection modification factors of multistory buildings considering soil-structure interaction

在线全文

学校读者我要写书评

暂无评论

Earthquake engineering and engineering Vibration 2015年第3期14卷 561-570页

作者： Farhad Abedi-Nik Faramarz Khoshnoudian department of civil engineering SADRA Institute of Higher Education department of civil engineering Amirkabir University of Technology

In this investigation,attempts are made to examine the effects of soil-structure interaction on the deflection modification factor of multistory buildings and to clarify the role of deformable soil on this factor.A comprehensive study is conducted to investigate the effect of inertial interaction on displacement demand ratios in soil-structure systems with different structural characteristics and various non-dimensional parameters,using a simplified interacting model.A two-step regression analysis of the nonlinear,dynamic computer simulation results obtained,leads to a reliable and accurate formula for predicting deflection modification factors that incorporate foundation *** results illustrate that the application of deflection modification factors derived from fixed-base structures can lead to unsafe evaluation of the structures on soft *** proposed formula provides a useful tool for design engineers to incorporate the effect of soil-structure interaction into the evaluation of structural deformations.

关键词： defl ection modifi cation factor multistory struct

Imperialistic Competitive Algorithm:A metaheuristic algorithm for locating the critical slip surface in 2-Dimensional soil slopes

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2016年第1期7卷 83-89页

作者： Ali Reza Kashani Amir Hossein Gandomi Mehdi Mousavi department of civil engineering Arak University department of civil engineering The University of Akron

In this study, Imperialistic Competitive Algorithm（ICA） is utilized for locating the critical failure surface and computing the factor of safety（FOS） in a slope stability analysis based on the limit equilibrium approach. The factor of safety relating to each trial slip surface is calculated using a simplified algorithm of the Morgenstern-Price method, which satisfies both the force and the moment equilibriums. General slip surface is considered non-circular in this study that is constituted by linking random straight *** explore the performance of the proposed algorithm, four benchmark test problems are analyzed. The results demonstrate that the present techniques can provide reliable, accurate and efficient solutions for locating the critical failure surface and relating FOS. Moreover, in contrast with previous studies the present algorithm could reach the lower value of FOS and reached more exact solutions.

关键词： Meta-heuristic algorithms Morgen-stern and price method Non-circular slip surface Imperialistic competitive algorithm

Pseudo-dynamic analysis of seismic stability of reinforced slopes considering non-associated flow rule

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2011年第6期18卷 2091-2099页

作者： A.Eskandarinejad A.H.Shafiee civil engineering department University of Hormozgan civil engineering department Shiraz University

The required reinforcement force to prevent instability and the yield acceleration of reinforced slopes are computed under seismic loading by applying the kinematic approach of limit analysis in conjunction with the pseudo-dynamic method for a wide range of soil cohesion, friction angle, dilation angle and horizontal and vertical seismic coefficients. Each parameter threatening the stability of the slope enhances the magnitude of the required reinforcement force and vice versa. Moreover, the yield acceleration increases with the increase in soil shear strength parameters but decreases with the increase in the slope angle. The comparison of the present work with some of the available solutions in the literatures shows a reasonable agreement.

关键词： reinforced slope seismic stability pseudo-dynamic approach non-associated flow rule cohesive slope

Seismic performance and global ductility of RC frames rehabilitated with retrofi tted joints by CFRP laminates

在线全文

学校读者我要写书评

暂无评论

Earthquake engineering and engineering Vibration 2014年第1期13卷 59-73页

作者： M.Fakharifar M.K. Sharbatdar Z.Lin A.Dalvand A.Sivandi-Pour G.Chen department of civil Architectural and Environmental EngineeringMissouri University of Science and Technology department of civil engineering Semnan University department of civil and Environmental engineering North Dakota State University

This paper presents a new FRP retrofi tting scheme to strengthen local beam-column joints in reinforced concrete(RC) *** new retrofi tting scheme was proposed following a preliminary study of four different existing retrofi tting schemes.A numerical simulation was conducted to evaluate the effectiveness of FRP-strengthened reinforced concrete frames by bridging behavior of local joints to the whole *** confi nement effects due to varying retrofi tting schemes in the joints were simulated in the frame *** seismic behavior factor was used to evaluate the seismic performance of the strengthened RC *** results demonstrated that the new proposed retrofi tting scheme was robust and promising,and fi nite element analysis appropriately captured the strength and global ductility of the frame due to upgrading of the local joints.

关键词： beam-column joints behavior factor retrofit FRP dynamic analysis seismic performance

Suboptimal Rayleigh damping coefficients in seismic analysis of viscously-damped structures

在线全文

学校读者我要写书评

暂无评论

Earthquake engineering and engineering Vibration 2014年第4期13卷 653-670页

作者： Pan Danguang Chen Genda Wang Zuocai department of civil engineering University of Science and Technology Beijing department of civil Architectural and Environmental Engineering Missouri University of Science and Technology department of civil engineering Hefei University of Technology

An optimization method for the consistent evaluation of two Rayleigh damping coefficients is proposed. By minimizing an objective function such as an error term of the peak displacement of a structure, the two coefficients can be determined with response spectral analysis. The optimization method degenerates into the conventional method used in current practices when only two modes of vibration are included in the objective function. Therefore, the proposed method with all significant modes included for simplicity in practical applications results in suboptimal damping coefficients. The effects of both spatial distribution and frequency content of excitations as well as structural dynamic characteristics on the evaluation of Rayleigh damping coefficients were investigated with a five-story building structure. Two application examples with a 62-story high-rise building and a 840 m long cable-stayed bridge under ten earthquake excitations demonstrated the accuracy and effectiveness of the proposed method to account for all of the above effects.

关键词： Rayleigh damping response spectral analysis structural dynamics structural analysis optimization method

Nonlinear dynamic analysis of multi-base seismically isolated structures with uplift potentialⅡ:verification examples

在线全文

学校读者我要写书评

暂无评论

Earthquake engineering and engineering Vibration 2010年第1期9卷 83-91页

作者： Panayiotis C.Roussis Panos C.Tsopelas Michael C.Constantinou department of civil and Environmental engineering University of Cyprus department of civil engineering University of Thessaly department of civil Structural and Environmental EngineeringUniversity at BuffaloState University of New York

The work presented in this paper serves as numerical verification of the analytical model developed in the companion paper for nonlinear dynamic analysis of multi-base seismically isolated structures. To this end, two numerical examples have been analyzed using the computational algorithm incorporated into program 3D-BASIS-ME-MB, developed on the basis of the newly-formulated analytical model. The first example concerns a seven-story model structure that was tested on the earthquake simulator at the University at Buflhlo and was also used as a verification example for program SAP2000. The second example concerns a two-tower, multi-story structure with a split-level seismic-isolation system. For purposes of verification, key results produced by 3D-BASIS-ME-MB are compared to experimental results, or results obtained from other structural/finite element programs. In both examples, the analyzed structure is excited under conditions of bearing uplift, thus yielding a case of much interest in verifying the capabilities of the developed analysis tool.

关键词： seismic isolation nonlinear dynamic analysis uplift verification multiple superstructures/bases

Liquefaction mitigation in silty soils using composite stone columns and dynamic compaction

在线全文

学校读者我要写书评

暂无评论

Earthquake engineering and engineering Vibration 2004年第1期3卷 39-50页

作者： T.Shenthan R.Nashed S.Thevanayagam G.R.Martin department of civil engineering

The objective of this study is to develop an analytical methodology to evaluate the effectiveness of vibro stone column (S.C.) and dynamic compaction (D.C.) techniques supplemented with wick drains to densify and mitigate liquefaction in saturated sands and non-plastic silty soils. It includes the following: (i) develop numerical models to simulate and analyze soil densitication during S.C. installation and D.C. process, and (ii) identify parameters controlling post-improvement soil density in both cases, and (iii) develop design guidelines for densification of silty soils using the above techniques. An analytical procedure was developed and used to simulate soil response during S.C. and D.C. installations, and the results were compared with available case history data. Important construction design parameters and soil properties that affect the effectiveness of these techniques, and construction design choices suitable for sands and non-plastic silty soils were identified. The methodology is expected to advance the use of S.C. and D.C. in silty soils reducing the reliance on expensive field trials as a design tool. The ultimate outcome of this research will be design charts and design guidelines for using composite stone columns and composite dynamic compaction techniques in liquefaction mitigation of saturated silty soils.

关键词： liquefaction mitigation silty soils composite stone columns dynamic compaction

Effect of aggressive pH media on peat treated by cement and sodium silicate grout

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2011年第3期18卷 840-847页

作者： S.Kazemian A.Prasad B.B.K.Huat J.Bolouri Bazaz T.A.Mohammed F.N.Abdul Aziz department of civil engineering Bojnourd BranchIslamic Azad University department of civil engineering Banaras Hindu University department of civil engineering University Putra Malaysia department of civil engineering Ferdowsi University

The effects of aggressive peat nature (pH) on the strength of peat treated by cement and cement-sodium silicate grout were investigated by evaluating the changes in unconfined compressive strength,moisture content,and scanning electron microscopy (SEM) of samples with time in different pH *** results indicate that peats treated by cement-silicate have higher strength than peats treated by cement,due to an increase in pH value of the ***,cement and cement-silicate are highly effective in reducing the moisture content and void ratio of the treated *** microstructures of treated peats support the laboratory test results.

关键词： peat aggressive pH media cementation sodium silicate grout microstructure

Determination of reasonable finished state of self-anchored suspension bridges

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2016年第1期23卷 209-219页

作者：李建慧冯东明李爱群袁辉辉 College of civil engineering Nanjing Forestry University department of civil engineering and engineering Mechanics Columbia University College of civil engineering Southeast University College of civil engineering Fuzhou University

A systematic and generic procedure for the determination of the reasonable finished state of self-anchored suspension bridges is proposed, the realization of which is mainly through adjustment of the hanger tensions. The initial hanger tensions are first obtained through an iterative analysis by combining the girder-tower-only finite element(FE) model with the analytical program for shape finding of the spatial cable system. These initial hanger tensions, together with the corresponding cable coordinates and internal forces, are then included into the FE model of the total bridge system, the nonlinear analysis of which involves the optimization technique. Calculations are repeated until the optimization algorithm converges to the most optimal hanger tensions(i.e. the desired reasonable finished bridge state). The "temperature rigid arm" is introduced to offset the unavoidable initial deformations of the girder and tower, which are due to the huge axial forces originated from the main cable. Moreover, by changing the stiffness coefficient K in the girder-tower-only FE model, the stiffness proportion of the main girder, the tower or the cable subsystem in the whole structural system could be adjusted according to the design intentions. The effectiveness of the proposed method is examined and demonstrated by one simple tutorial example and one self-anchored suspension bridge.

关键词： self-anchored suspension bridge reasonable finished bridge state optimization algorithm finite element nonlinear relation