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1.
性态抗震设计已成为结构抗震设计的发展趋势,本文以约束混凝土砌块结构为对象,在提出约束混凝土砌块墙承载力计算公式的基础上,建立了砌块墙片的恢复力模型。对3座不同层数的典型约束混凝土砌块结构,在代表不同场地类别、不同地震动强度的输入下分别进行了动力非线性时程分析和静力非线性分析。通过计算结果的对比,讨论了2种分析方法中场地类别、地震动强度、静力非线性分析中侧力分布模式等影响,所得结论可以为用静力非线性分析估计砌块结构的抗震性能提供有益的参考依据。 相似文献
2.
Approximate seismic risk assessment of building structures with explicit consideration of uncertainties 
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下载免费PDF全文 An approximate seismic risk assessment procedure for building structures, which involves pushover analysis that is performed utilizing a deterministic structural model and uncertainty analysis at the level of the equivalent SDOF model, is introduced. Such an approach is computationally significantly less demanding in comparison with procedures based on uncertainty analysis at the level of the entire structure, but still allows for explicit consideration of the effect of record‐to‐record variability and modelling uncertainties. A new feature of the proposed pushover‐based method is the so‐called probabilistic SDOF model. Herein, the proposed methodology is illustrated only for reinforced concrete (RC) frames, although it could be implemented in the case of any building structure, provided that an appropriate probabilistic SDOF model is available. An extensive parametric analysis has been performed within the scope of this study in order to develop a probabilistic SDOF model, which could be used for the seismic risk assessment of both code‐conforming and old, that is, non code‐conforming RC frames. Based on the results of risk analysis for the four selected examples, it is shown that the proposed procedure can provide conservative estimates of seismic risk with reasonable accuracy, in spite of the employed simplifications and the relatively small number of Monte Carlo simulations with Latin hypercube sampling, which are performed at the level of the SDOF model. An indication of the possible default values of dispersion measures for limit‐state intensities in the case of low to medium‐height RC frames is also presented. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
3.
Alternative static pushover methods for the seismic design of new structures are assessed with the aid of advanced computational tools. The current state-of-practice static pushover methods as suggested in the provisions of European and American regulations are implemented in this comparative study. In particular the static pushover methods are: the displacement coefficient method of ASCE-41, the ATC-40 capacity spectrum method and the N2 method of Eurocode 8. Such analysis methods are typically recommended for the performance assessment of existing structures, and therefore most of the existing comparative studies are focused on the performance of one or more structures. Therefore, contrary to previous research studies, we use static pushover methods to perform design and we then compare the capacity of the outcome designs with reference to the results of nonlinear response history analysis. This alternative approach pinpoints the pros and cons of each method since the discrepancies between static and dynamic analysis are propagated to the properties of the final structure. All methods are implemented in an optimum performance-based design framework to obtain the lower-bound designs for two regular and two irregular reinforced concrete building configurations. The outcome designs are compared with respect to the maximum interstorey drift and maximum roof drift demand obtained with the Incremental Dynamic Analysis method. To allow the comparison, also the life-cycle cost of each design is calculated; i.e. a parameter that is used to measure the damage cost due to future earthquakes that will occur during the design life of the structure. The problem of finding the lower bound designs is handled with an Evolutionary type optimization algorithm. 相似文献
4.
基于性能的碳纤维抗震加固设计 总被引：2，自引：1，他引：1
本文探讨了基于性能的加固设计的基本思路和设计过程,并给出了一个基于性能的碳纤维加固设计的工程实例,采用pushover静力推覆分析的方法分析对比了结构加固前后的性能,表明原结构的抗震性能不足,经碳纤维加固后的结构抗震性能明显提高,满足8度抗震设防烈度要求。 相似文献
5.
Estimating seismic demands on structures, to predict their performance level with confidence, requires explicit consideration
of the structural inelastic behaviour: to this end, the use of nonlinear static procedures is inevitably going to be favoured
over complex nonlinear time-history methods.
The currently available assessment procedures have been tested predominantly against building frames. A newly derived assessment
procedure is proposed within the scope of bridge applications, based on an innovative displacement-based adaptive pushover
technique. The procedure, which can be incorporated into a performance-based engineering philosophy, is applicable to MDOF
continuous span bridges with flexible or rigid superstructures, and for varying degrees of abutment restraint.
As a first application to determine the viability of the proposed procedure, a parametric study is conducted on a ensemble
of bridges subjected to earthquake motion. It is shown that, compared to the seismic demand estimated by means of the more
accurate nonlinear dynamic analysis tool, the novel static assessment method can lead to the attainment of satisfactory predictions,
both in terms of displacement as well as moment demand on members. 相似文献
6.
交错桁架多层钢结构推倒分析方法研究 总被引：1，自引：0，他引：1
随着基于性能的抗震设计思想的发展,推倒分析开始成为罕遇地震下多、高层结构抗震设计的有力工具。本文以交错桁架多层钢结构为例,采用推倒分析对其在E l Centro波作用下的地震反应进行研究,分别采用位移系数法和能力谱法确定结构目标位移,同时进行结构在相同地震动下的弹塑性时程分析。研究表明,推倒分析能准确地评价交错桁架多层钢结构的抗震性能,采用位移系数法和能力谱法确定的结构顶点侧移均与弹塑性时程分析吻合较好,对层间位移及塑性铰分布的预测,能力谱法比位移系数法更为准确。 相似文献
7.
The increasing popularity of simplified nonlinear methods in seismic design has recently led to many proposals for procedures aimed at extending pushover analysis to plan asymmetric structures. In terms of practical applications, one particularly promising approach is based on combining pushover analysis of a 3D structural model with the results of linear (modal) dynamic analysis. The effectiveness of such procedure, however, is contingent on one fundamental requirement: the elastic prediction of the envelope of lateral displacements must be conservative with respect to the actual inelastic one. This paper aims at verifying the above assumption through an extensive parametric analysis conducted with simplified single‐storey models. The main structural parameters influencing torsional response in the elastic and inelastic range of behaviour are varied, while devoting special attention to the system stiffness eccentricity and radius. The analysis clarifies the main features of inelastic torsional response of different types of building structures; in this manner, it is found that the above‐mentioned method is generally suitable for structures characterized by moderate to large torsional stiffness, whereas it cannot be recommended for extremely torsionally stiff structures, as their inelastic torsional response almost always exceeds the elastic one. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
8.
The determination of displacement demands for masonry buildings subjected to seismic action is a key issue in the performance-based assessment and design of such structures. A technique for the definition of single-degree-of-freedom (SDOF) nonlinear systems that approximates the global behaviour of multi-degree-of-freedom (MDOF) 3D structural models has been developed in order to provide useful information on the dependency of displacement demand on different seismic intensity measures. The definition of SDOF system properties is based on the dynamic equivalence of the elastic properties (vibration period and viscous damping) and on the comparability with nonlinear hysteretic behaviour obtained by cyclic pushover analysis on MDOF models. The MDOF systems are based on a nonlinear macroelement model that is able to reproduce the in-plane shear and flexural cyclic behaviour of pier and spandrel elements. For the complete MDOF models an equivalent frame modelling technique was used. The equivalent SDOF system was modelled using a suitable nonlinear spring comprised of two macroelements in parallel. This allows for a simple calibration of the hysteretic response of the SDOF by suitably proportioning the contributions of flexure-dominated and shear-dominated responses. The comparison of results in terms of maximum displacements obtained for the SDOF and MDOF systems demonstrates the feasibility and reliability of the proposed approach. The comparisons between MDOF and equivalent SDOF systems, carried out for several building prototypes, were based on the results of time-history analyses performed with a large database of natural records covering a wide range of magnitude, distance and local soil conditions. The use of unscaled natural accelerograms allowed the displacement demand to be expressed as a function of different ground motion parameters allowing for the study of their relative influence on the displacement demand for masonry structures. 相似文献
9.
Pushover分析方法中各种不同的侧向荷载分布方式的影响 总被引：3，自引：1，他引：3
目前基于性能的抗震设计研究方兴未艾，其中pushover分析方法作为目前主要的可供操作的抗震设计方法得到广泛的研究。在pushover分析方法中，其中一个关键的问题就是侧向荷载分布方式的确定，因此对各种不同荷载分布方式作综合的分析与比较研究非常有必要。总结了前人所提出的各种不同的侧向荷载分布方式，同时提出一种新的瞬时适应性的侧向荷载分布方式，通过两个实例分析比较了各种不同荷载分布方式的适用范围、有效性及其对结构弹塑性分析结果的影响。 相似文献
10.
Abdallah Yacine Rahmani Nouredine Bourahla Rita Bento Mohamed Badaoui 《Bulletin of Earthquake Engineering》2018,16(1):315-339
In recent years, nonlinear static procedures (NSPs) have gained considerable popularity as an efficient tool in the performance based seismic design practice. This was backed by extensive corroboration studies that have demonstrated its good accuracy in estimating the seismic response of regular structures. Despite the numerous improvements of the original versions of NSPs, their use to assess the seismic response of irregular structures and high-rise buildings is still challenging; they are not able to predict with sufficient accuracy all the complexities associated to the seismic response of this type of structures. Thus, an improved upper-bound (IUB) pushover procedure for seismic assessment of plane frames is presented in this paper, aiming to enhance the accuracy of existing methods in predicting the seismic behaviour of high-rise buildings. The novelty of this proposal is based on the adjustment of the pattern of the lateral load of the upper-bound pushover method applied to tall structures. The accuracy of the procedure is tested using nine, twelve, fifteen and twenty storeys steel buildings. The results of the (IUB) are compared to those of the capacity spectrum method, the modal pushover analysis, the upper bound pushover analysis, the modified upper bound pushover analysis and the non-linear time history analysis (NTHA). In most cases, the proposed procedure shows better results and closer to those obtained by NTHA. 相似文献
11.
Several procedures for non-linear static and dynamic analysis of structures have been developed in recent years. This paper
discusses those procedures that have been implemented into the latest European and US seismic provisions: non-linear dynamic
time-history analysis; N2 non-linear static method (Eurocode 8); non-linear static procedure NSP (FEMA 356) and improved capacity
spectrum method CSM (FEMA 440). The presented methods differ in respect to accuracy, simplicity, transparency and clarity
of theoretical background. Non-linear static procedures were developed with the aim of overcoming the insufficiency and limitations
of linear methods, whilst at the same time maintaining a relatively simple application. All procedures incorporate performance-based
concepts paying more attention to damage control. Application of the presented procedures is illustrated by means of an example
of an eight-storey reinforced concrete frame building. The results obtained by non-linear dynamic time-history analysis and
non-linear static procedures are compared. It is concluded that these non-linear static procedures are sustainable for application.
Additionally, this paper discusses a recommendation in the Eurocode 8/1 that the capacity curve should be determined by pushover
analysis for values of the control displacement ranging between zero and 150% of the target displacement. Maximum top displacement
of the analyzed structure obtained by using dynamic method with real time-history records corresponds to 145% of the target
displacement obtained using the non-linear static N2 procedure. 相似文献
12.
This paper presents a new procedure to transform an SSI system into an equivalent SDOF system using twice equivalence. A pushover analysis procedure based on the capacity spectrum method for buildings with SSI effects （PASSI） is then established based on the equivalent SDOF system, and the modified response spectrum and equivalent capacity spectrum are obtained. Furthermore, the approximate formulas to obtain the dynamic stiffness of foundations are suggested. Three steel buildings with different story heights （3, 9 and 20） including SSI effects are analyzed under two far-field and two near-field historical records and an artificial seismic time history using the two PASSI procedures and the nonlinear response history analysis （NLhRHA） method. The results are compared and discussed. Finally, combined with seismic design response spectrum, the nonlinear seismic response of a 9-story building with SSI effects is analyzed using the PASSI procedures, and its seismic performance is evaluated according to the Chinese ＇Code for Seismic Design of Buildings. The feasibility of the proposed procedure is verified. 相似文献
13.
Incremental dynamic analysis and nonlinear static pushover analysis are carried out on a performance-based design to determine the seismic demands and capacities of an elliptic braced moment resisting frame (ELBRF). The objective is to assess ductility, overstrength and response modification factors in a modern steel-braced structural system based on incremental dynamic analysis. This integrated system is connected to a beam and column with an appropriate length while providing enough architectural space to allow for an opening without having the common problems associated with architectural spaces in braced systems. Several different classes of buildings are considered on soil type II. Linear dynamic analysis, nonlinear static pushover analysis and incremental nonlinear dynamic analysis related to 12 records from past earthquakes are carried out using OpenSees software. The factors of ductility, overstrength and response modification are calculated for this system. The values of 9.5 and 6.5 are found and suggested only for the response modification factor for ELBRF systems in allowable stress and ultimate limit state methods, respectively. The fragility curves are plotted for the first time for this type of bracing, which contributes to the assessment of building seismic damage. 相似文献
14.
This paper presents the development and assessment of a simplified procedure for estimating the seismic sidesway collapse margin ratio of building structures. The proposed procedure is based on the development of a robust database of seismic peak displacement responses of nonlinear single‐degree‐of‐freedom systems for various seismic intensities and uses nonlinear static (pushover) analysis without the need for nonlinear time history dynamic analysis. The proposed simplified procedure is assessed by comparing its collapse capacity predictions on 72 different building structures with those obtained by nonlinear incremental dynamic analyses. The proposed simplified procedure offers a simple, yet efficient, computational/analytical tool that is capable of predicting collapse capacities with acceptable accuracy for a wide variety of frame building structures. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
15.
Seismic safety of low ductility structures used in Spain 总被引：1，自引：0，他引：1
The most important aspects of the design, seismic damage evaluation and safety assessment of structures with low ductility
like waffle slabs buildings or flat beams framed buildings are examined in this work. These reinforced concrete structural
typologies are the most used in Spain for new buildings but many seismic codes do not recommend them in seismic areas. Their
expected seismic performance and safety are evaluated herein by means of incremental non linear structural analysis (pushover
analysis) and incremental dynamic analysis which provides capacity curves allowing evaluating their seismic behavior. The
seismic hazard is described by means of the reduced 5% damped elastic response spectrum of the Spanish seismic design code.
The most important results of the study are the fragility curves calculated for the mentioned building types, which allow
obtaining the probability of different damage states of the structures as well as damage probability matrices. The results,
which show high vulnerability of the studied low ductility building classes, are compared with those corresponding to ductile
framed structures. 相似文献
16.
The opportunities provided by the use of fiber‐reinforced polymer (FRP) for the seismic retrofit of existing reinforced concrete (RC) structures were assessed on a full‐scale three‐story framed structure. The structure, designed only for gravity loads, was subjected to a bi‐directional pseudo‐dynamic (PsD) test at peak ground acceleration (PGA) equal to 0.20g at the ELSA Laboratory of the Joint Research Centre. The seismic deficiencies exhibited by the structure after the test were confirmed by post‐test assessment of structural seismic capacity performed by nonlinear static pushover analysis implemented on the lumped plasticity model of the structure. In order to allow the structure to withstand 0.30g PGA seismic actions, a retrofit using glass fiber‐reinforced polymer (GFRP) laminates was designed. The retrofit design was targeted to achieve a more ductile and energy dissipating global performance of the structure by increasing the ductility of columns and preventing brittle failure modes. Design assumptions and criteria along with nonlinear static pushover analysis to assess the overall capacity of the FRP‐retrofitted structure are presented and discussed. After the retrofit execution, a new series of PsD tests at both 0.20g and 0.30g PGA level were carried out. Theoretical predictions are compared with the main experimental outcomes to assess the effectiveness of the proposed retrofit technique and validate the adopted design procedures. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
17.
延性需求谱在基于性能的抗震设计中的应用 总被引：23，自引：4，他引：19
基于性能的抗震设计理论涉及如何简便而合理地确定结构在指定强度地震下的弹塑性位移需求。本文给出了利用延性需求谱求解结构位移需求的一般步骤:借助模态Pushover分析将多自由度体系分解为几个非线性单自由度体系,以考虑各阶振型的影响;利用延性需求谱计算对应模态的等效单自由度体系的延性及位移需求,并以一定方式组合转化为多自由度体系位移需求。最后,通过算例分析表明:利用延性需求谱求解结构位移需求是一种具有一定精度可为工程接受的简便方法,在基于性能的抗震设计中具有较好的应用前景。 相似文献
18.
The performance‐based philosophy has been accepted as a more reasonable design concept for engineering structures. For this purpose, capacity evaluation and demand prediction procedures for civil engineering structures under earthquake excitations are of great significance. This work presents a displacement‐based seismic performance verification procedure including capacity and seismic demand predictions for steel arch bridges and investigates its applicability. Pushover analyses is employed as a basis in this method to investigate the structure's behaviors. A failure criterion for steel members accounting for the effect of local buckling is involved and an equivalent single‐degree‐of‐freedom (ESDOF) system with a simplified bilinear hysteretic model formulated using pushover analyses results is introduced to estimate the displacement capacity and maximum demand of steel arch bridges under major earthquakes. To check the accuracy of the proposed method, seismic capacities and demands from multi‐degree‐of‐freedom (MDOF) time‐history analyses with Level‐II design earthquake record inputs modeling major earthquakes are used as benchmarks for comparison. By a case study, it is clarified that the proposed prediction procedure can give accurate estimations of displacement capacities and demands of the steel arch bridge in the transverse direction, while insufficient for the longitudinal direction, which confirms the conclusion drawn in other structure types about the applicability of pushover analyses. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
19.
A setback building has a sudden discontinuity in the frame geometry along the height. This kind of irregularity causes an abrupt discontinuity in stiffness, strength and mass of the building frame. In this study, a total of nineteen mid-rise 9-story steel moment resisting frames with setbacks including the broad range of different geometrical configurations were studied. An eigenvalue analysis was performed to evaluate and scrutinize the dynamic characteristics of setback structures. The effect of geometrical configurations on the seismic responses of setback frames was studied by means of nonlinear response history analysis using a set of far-field ground motion records. Moreover, due to the rapidly increasing use of pushover analysis for the seismic evaluation of structures in recent years, enhanced pushover analyses (EPAs) including the modal pushover analysis, the upper bound pushover analysis, the consecutive modal pushover and the extended N2 methods were implemented as a main part of this study. The findings show that two factors including the location of setback and the degree of setback are of key importance and influence the dynamic characteristics and seismic responses of setback structures. The degree of accuracy of the enhanced pushover analysis methods generally depends on the dynamic characteristics (geometrical configuration) of the setback frames. The largest error in the EPAs in predicting the story drifts generally occurs in a setback frame with a larger amount of the ratio between the effective modal participating mass ratio of the higher modes and that of the first mode. 相似文献
20.
《地震研究进展（英文）》2022,2(4):100118
The pushover method for underground structures is a seismic analysis method featured by high calculation accuracy and a simple implementation process. The method has been widely used in seismic design and other related scientific research; however, the influence of different soil-structure flexibility ratios on the accuracy of this method is still not well understood. In this study, we select the cross-section structures beneath the Daikai subway station as the research object and establish 12 finite element analysis models with different soil-structure flexibility ratios using ABAQUS. All models are computed by the dynamic time-history method or the pushover method. Furthermore, the dynamic time-history solution result is taken as the standard solution, and the precision and application of the pushover analysis method are discussed based on the parameters of peak interlayer displacement and peak internal force of the middle column section. The results show that the soil-structure flexibility ratio has a significant influence on the calculation accuracy of the pushover method, and the calculation accuracy of this method is the most ideal when the soil-structure flexibility is equal to 1. The research results can provide significant references for the seismic design of underground structures or the improvement of simplified seismic analysis methods. 相似文献