Papers by Keyword: Capacity Spectrum Method

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Authors: Mohammad Ahmadi, Suhaimi Abu Bakar
Abstract: In recent decades Performance Based Seismic Design (PBSD) is widely used for evaluation of the structural performance because of its capability and simplicity to estimate inelastic response of structure. On the other hand, some times in construction based on architectural decision, size of beams are being decreased. The aim of this attempt is to investigate the effect of beam size on structural behavior based on PBSD method using simple procedure. Capacity Spectrum Method (CSM) was implemented using set of RC frames (2, 4, 6, 8 and 10 story with three bays) and ETABS2000 to determine the weakness of the frames system due to their reduced beam size. The performance of the frames was measured at Life Safety damage control level.
Authors: Iolanda Gabriela Craifaleanu
Abstract: During recent years, an increasing number of studies advocate the application of the capacity spectrum method based demand diagrams computed directly from inelastic response spectra, as an alternative to the basic formulation of the method, which uses elastic spectra computed for single degree-of-freedom oscillators with modified characteristics to account for inelastic behavior. When demand diagrams are based on the code-specified elastic spectrum, inelastic spectra are typically determined by dividing the elastic spectrum by strength reduction factors. The paper presents the application of the method, based on strength reduction factors computed with a unified analytical expression, deduced by the author in previous studies. The expression and is valid both for broadband and narrow band ground motions. Taking as a starting point the newly-enforced elastic design spectra in the 2013 edition of the Romanian seismic design code, the method is exemplified for the capital city, Bucharest. It is shown that, for the analyzed case, the use of the proposed strength reduction factors leads to results that are very close to those obtained by the “classical” nonlinear static procedure used in the code. This suggests a good potential for the implementation of the capacity spectrum method in the Romanian code, based on these factors.
Authors: Qing Xuan Shi, Qiu Wei Wang, Kun Yang
Abstract: To further understand displacement based seismic theory of building structures, the seismic performance evaluation using capacity spectrum method related to damping is carried out for the reinforced concrete frame-shear wall model structure of a thermal power main plant. By comparing with time-history analysis results, it can be seen that some problems such as equivalence of multi-degree-of-freedom system and value of equivalent damping ratio in capacity spectrum method remains to be further investigated. Force and displacement response of structures and plastic hinges position of all members could be obtained through nonlinear push-over analysis after determining the top displacement; weak parts and damage pattern of structures could also be easily found out by this method. At last, research shows that dynamic time-history analysis can be replaced by static push-over analysis, which is regarded as an exact seismic performance evaluation method by contrast.
Authors: S. Swathi, Katta Venkataramana, C. Rajasekaran
Abstract: Performance-based seismic design (PBSD) is an approach, in which the design aim is to deliver a structure capable of meeting certain predictable performance objectives under different levels of earthquake motions. In order to ensure the desirable performance of buildings or structures, the structural parameters such as strength, stiffness and ductility or deformability should be reasonably proportioned. Conventional methods of seismic design have the objectives to provide life safety (strength and ductility) and damage control (serviceability drift limits). However, little information is available on how the building reacts to a seismic hazard. The basic concept of PBSD is to provide the engineers with the capability to design buildings that have a predictable and reliable performance in case of a seismic hazard. This procedure compares the capacity of a structure (in the form of a pushover curve), with the demand imposed by the earthquake on the structure (in the form of response spectra).The present paper determines the performance point of the structure, using Capacity Spectrum Method (CSM). A 7-storey building has been considered for this purpose and pushover analysis is carried out. An attempt has been made to perform the seismic analysis for the building, to obtain the performance point.
Authors: Hai Tao Wan, Lin Yang
Abstract: In order to overcome some deficiency of design, American earthquake engineering and structural engineering experts have profound conclusion after the previous earthquakes, improved bearing capacity design method, put forward the theory of performance-based design. Methods of performance-based design mainly include displacement coefficient method; direct displacement based design method, capacity spectrum method and improved capacity spectrum method. Through the understanding of the main methods, enable us to better understand performance-based design, so as to improve the design of civil engineering.
Authors: Yue Chen
Abstract: The height of a complex supertall building is 250m. The central RC tube and peripheral SRC frame with two outrigger trusses are employed to resist vertical and lateral loads. It is classified as B grade complex tall building due to the structural characteristic. Due to the over-restriction and complexity of the super tall-building, Pushover Analysis is carried out in order to find it’s behaviors under rare intensity earthquakes. The analytical results demonstrate that the SRC supertall building with high level transfer story possesses good energy-consuming capacity, ductility and ideal yield failure mechanism under rare seismic excitation. Seismic performance of the SRC supertall building is evaluated through Capacity Spectrum Method and good results are obtained.
Authors: Ivana Veghova
Abstract: Using capacity spectrum method was analyzed frame reinforced concrete structures. Capacity spectrum method has been used to analyse frame reinforced concrete structures. Geometry, material properties and reinforced cross sections were designed by experimental tested model of reinforced concrete frame joints in the scale of 1:1. The results were compared with the results of the analysis of the structure of the same geometrical characteristics but of standard material properties of concrete and steel.
Authors: Wen Xia Yang, Qiang Gu, Zhen Sen Song
Abstract: In current seismic design procedure, structural base shear is calculated according to the linear elastic response spectra divided by response modification factor R. The response modification factor is important to the reliability and economy of building seismic design. In this paper, the response modification factors of Twelve Y-eccentric braced steel frames with various stories and spans lengths were evaluated by capacity spectrum method based on the global capacity envelops obtained from an improved pushover analysis and incremental dynamic analysis. According to the results, an appropriate formula of the response modification factor for the Y-eccentric braced steel frames was suggested.
Authors: Jian Hua Shao, Qun Wu
Abstract: The seismic behavior factor of moment resisting steel frame-steel plate shear wall under two different horizontal loading patterns was investigated according to the maximum inter-story drift ratio reaching 1/50. It could be achieved with the same calculated standard as the foreign codes and the determined behavior factor was compared with foreign research results. The method using the software SAP2000 to calculate seismic behavior factor according to the maximum inter-story drift ratio reaching 1/50 was presented and the specific example was used to elaborate the operating process. The seismic behavior factor R, the overstrength factor RΩ and the ductility reduction factor Rμ of 10-storey 3-span steel frame-steel plate shear wall under the inverted triangle load are respectively 6.07, 2.96 and 2.05. while they are respectively 7.2, 3.37 and 2.13 under the uniform load. Finally, it can be concluded that the economic and reasonable design goals are achieved for this structure.
Authors: Shen Yongkang, Wang Zhengzhong
Abstract: According to the seismic demand spectra form the code for seismic design of buildings, seismic performances of eccentrically braced steel frames (EBF) in frequently, fortification and seldom occurred different intensity earthquakes were evaluated by the Capacity Spectrum Method (CSM). The capacity curves derived from base force-top displacement curves of structures subjected to the lateral seismic load of seismic codes were obtained from pushover analysis by applying sap2000 software and transformed to the spectrum curves, seismic performance were evaluated according to the intersection between the seismic demand spectra and the capacity spectrum. Seismic performances of 15 EBFs designed according to the Chinese design codes were evaluated by CSM. The certain ductility and displacement capacity of EBF in accordance with the China corresponding design codes are shown and some reference is suggested.
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