A Comparative Study of Design Base Shear for RC Buildings in Selected Seismic Design Codes

2012 ◽  
Vol 28 (3) ◽  
pp. 1047-1070 ◽  
Author(s):  
Vijay Namdev Khose ◽  
Yogendra Singh ◽  
Dominik H. Lang

Modern seismic building design codes tend to converge on issues of design methodology and the state-of-the-art. However, significant differences exist in basic provisions of various codes. This paper compares important provisions related to the seismic design of RC buildings in some of the major national seismic building codes viz. ASCE 7, Eurocode 8, NZS 1170.5, and IS 1893. Code provisions regarding the specification of hazard, site classification, design response spectrum, ductility classification, response reduction factors, and minimum design base shear are compared and their cumulative effect on design base shear is studied. The objective component of overstrength contributed by the material and load factors is considered to normalize the design base shear. It is observed that every code has merit over the other codes in some aspect. The presented discussion highlights the major areas of differences which need attention in the process of harmonization of different codes of the world.

2011 ◽  
Vol 378-379 ◽  
pp. 306-309
Author(s):  
Ping Li ◽  
Jing Shan Bo ◽  
Xiao Yun Guo ◽  
You Wei Sun ◽  
Yu Dong Zhang

Regarding the design response spectrum in the code for seismic design of buildings as target spectra,the 28 acceleration histories are formed artificially.They are used as the inputs ground motion in earthquake response analysis.Four site classifications profiles were selected or constructed from practical site profiles.With the use of 1-D equivalent linearization wave motion method that is wildly used at present in site seismic response analysis, the platform values of surface response spectrum for different profiles under different ground motion inputs were calculated.Different platform values of the response spectrum and relational expression which is seven input earthquake motion intensity and site classifications have been given by statistical analysis.


Author(s):  
N. Kokavesis ◽  
Ch. Botsis

The design of pressurized equipment such as columns, towers and reactors, heaters subjected to external loads is important from a safety point of view. Pressure vessel design codes provide guidelines for the combination of membrane stresses due to external loads and hoop stress. Customarily the seismic loads imposed by pressure vessel design codes are functions of allowable stress. The factor R is a modification factor of the design response spectrum. Its numerical value is based the capacity of a structural system to resist seismic actions in the nonlinear range. It generally reduces the seismic design forces to be smaller than those corresponding to a linear elastic response. The Uniform Building Code (UBC) has been used extensively for the seismic design of pressure vessels. With the advent of EUROCODES [2], the values proposed by UBC for factor R (usually 3 or 4) are not automatically accepted by local authorities. The pressure vessel mechanical designer must select a factor R that satisfies both the requirements of the pressure vessel code and the structural design code (local code) where the vessel is installed. This problem has also been acknowledged by several collogues in the past PVP conferences. In this paper the factor R is examined using ASME [10] codes and the guidelines provided by EUROCODES. A common basis for the selection of the factor R that satisfies both allowable stress design philosophies and structural design codes is established.


2012 ◽  
Vol 166-169 ◽  
pp. 2345-2352
Author(s):  
Zhi Nan Jiang ◽  
Zhong Hai Zhao

Seismic design response spectrum and earthquake action in Chinese new seismic code (GB50011-2010), ASCE/SEI7-05 and Eurcode8 were gathered in this paper. Using base shear force method of each code, the authors computed the horizontal seismic forces of a three-story reinforced concrete frame building under the same conditions. The results show that the three static methods roughly approach, while the different parameters lead to discrepancies in calculated values.


2013 ◽  
Vol 7 (1) ◽  
pp. 221-229 ◽  
Author(s):  
Jaime Landingin ◽  
Hugo Rodrigues ◽  
Humberto Varum ◽  
António Arêde ◽  
Aníbal Costa

The present paper presents a comparison of seismic provisions of three seismic design codes, the Philippine code, Eurocode 8 and the American code, to the most common ordinary residential frames of standard occupancy. Regular and irregular reinforced concrete frames were analyzed and compared for four storey building types. The response spectrum and the seismic parameters of NSCP 2010 were considered for the horizontal load action with different load combinations. Response spectrum analysis and equivalent lateral force analysis were performed using SAP2000 software package. Five representative columns for each RC frame structure were analyzed. Based on the results of column axial load - bending moment interaction diagrams, EC8 was found to be conservative when compared to NSCP 2010 and 2009 IBC. The conclusion is that for the design and analysis of ordinary RC residential buildings with certain irregularity, EC8 provisions were considered to be safer.


Author(s):  
Dion Marriott

This paper discusses the application of the Structural Performance factor (SP) within a Direct Displacement-Based Design framework (Direct-DBD). As stated within the New Zealand loadings standard, NZS1170.5:2004 [1], the SP factor is a base shear multiplier (reduction factor) for ductile structures, i.e. as the design ductility increases, the SP factor reduces. The SP factor is intended to acknowledge the better-than-expected structural behaviour of ductile systems (both strength, and ductility capacity) by accounting for attributes of response that designers are unable to reliably estimate. The SP factor also recognizes the less dependable seismic performance of non-ductile structures, by permitting less of a reduction (a larger SP factor) for non-ductile structures. Within a traditional force-based design framework the SP factor can be applied to either the design response spectrum (a seismic hazard/demand multiplier), or as a base shear multiplier at the end of design (structural capacity multiplier) – either of these two approaches will yield an identical design in terms of the required design base shear and computed ULS displacement/drift demands. However, these two approaches yield very different outcomes within a Direct-DBD framework – in particular, if SP is applied to the seismic demand, the design base shear is effectively multiplied by (SP)2 (i.e. a two-fold reduction). This paper presents a “DBD-corrected” SP factor to be applied to the design response spectrum in Direct-DBD in order to achieve the intent of the SP factor as it applies to force-based design. The proposed DBD-corrected SP factor is attractive in that it is identical to the SP relationship applied to the elastic site hazard spectrum C(T) for numerical integration time history method of analysis within NZS 1170.5:2004 [1], SP,DDBD = (1+SP)/2.


2019 ◽  
Vol 8 (4) ◽  
pp. 3821-3826

Staircase and elevator are the main structural components in multi-story buildings to enable access to different floor levels. In many Multi-storey buildings staircase and elevator core wall are located at different positions as per the benefits of structure plan and user. The position of the staircase and elevator core wall plays a vital role and changing the position of the stair case and core wall leads torsional irregularity in the plan regular building. The torsion in a building occurs because of eccentricity in the mass and stiffness distributions. The staircase and core wall is an integral part of the building, and its position may change the dynamic characteristic of regular plan building. In this paper, an attempt is made to understand the seismic behaviour of RC buildings with the effect of staircase and elevator core wall with changing position. Six models of 5 storey RC buildings with different positions of staircase and elevator core wall, i.e. ideal frame, Centre, Corner, Edge-Opposite, Edge-Adjacent and Corner with cantilever or balcony are considered. The modelling and analysis is done using ETABS v17. The response spectrum analysis and Modal analysis is performed, and Results of storey displacements, storey drift, storey shear, storey stiffness, base shear and torsion irregularity are discussed. From the results, it can be observed that building model with an edge-opposite position of staircase and elevator core wall performs better than other building model and torsion for it came within the code suggested ratio of 1.2.


2010 ◽  
Vol 163-167 ◽  
pp. 4395-4400
Author(s):  
Ben Yan Lu ◽  
Bo Quan Liu ◽  
Ming Liu ◽  
Guo Hua Xing

Earthquake codes have been revised and updated in recent years. The issue and implementation of the guidelines for seismic design of bridges have attracted interests and attentions of many researchs at home and abroad. In this paper, it is compared that the provisions about performance criteria, seismic design categories, response spectrum and earthquake action between guidelines for seismic design of highway bridges and Eurocode 8 for bridges. The main purpose of this study is to investigate the differences caused by the two codes in performance criteria, seismic design categories, response spectrum and earthquake action. The results indicate that it is similar in performance criteria, seismic design categories and response spectrum between guidelines for seismic design of highway bridges and Eurocode 8 for bridges. Based on the lessons learned from significant earthquakes in the last few years, the existing problems of the current code are pointed, and the trends of future study are discussed.


2016 ◽  
Vol 2 (4) ◽  
pp. 113-122 ◽  
Author(s):  
Ali Komak Panah ◽  
Aylin Nouri

Recent code provisions for building and other structures (1994 and 1997 NEHRP provisions, 1997 UBC) have adopted new site classification. The new site classification system is based on average shear wave velocity to a depth of 30 m. when the shear wave velocity is not available; other soil properties such as undrained shear strength can be used. The study of propagation damages in various earthquakes illustrates the importance of the site effect on the ground seismic characteristics. From the point of the earthquake engineering view, the most important characteristics of the strong ground motion are amplitude, frequency content and duration. All of these properties have a significant effect on earthquake damage. The behavior of soils under cyclic loading is basically nonlinear and hysteretic. Ground response analysis is used to predict the movements of the ground and develop a design response spectrum in order to determine the dynamic stresses and strains and earthquake forces. The profile was studied by using various methods of soil response analysis and finally, the results were examined. In this paper, soil responses were examined by NERA, EERA software and the results compared with each other. Eventually, we concluded that the values obtained from the EERA are more than the value obtained from the NEERA software.


2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Seung Dae Kim ◽  
Jaeyong Yoon ◽  
Wanjei Cho ◽  
Jungwhee Lee

Piloti-type structure is a popular architectural style consisting of only columns or minimum number of shear-resisting walls on the first floor. The large difference in lateral stiffness between the first and the upper floors makes the structure very vulnerable to earthquakes. Through the recent earthquakes in Gyeongju (2016) and Pohang (2017), due to such structural disadvantages, many damage cases have been reported, especially in low-rise piloti-type buildings with five stories or less. In this study, seismic soil-structure interaction (SSI) analysis is conducted on low-rise piloti-type buildings considering Korean geotechnical characteristics, and the effect is analytically evaluated. To achieve this goal, seismic SSI analysis applying the measured Gyeongju earthquake and design response spectrum (DRM) based on the architectural design codes are conducted by constructing three-dimensional structural analysis models with a five-story piloti-type building and four different soil properties: fill (FI), alluvial soil (AS), weathered soil (WS), and weathered rock (WR). From the analysis results, it is found that WS soil is largely affected by the seismic SSI, and the influence of the seismic SSI is different for each soil type regardless of the type of earthquake. Through the parameter study, simple and reasonable estimates are proposed to consider the SSI effect on the base shear in low-rise piloti-type buildings.


2012 ◽  
Vol 594-597 ◽  
pp. 812-815
Author(s):  
Jing Li ◽  
Xing Hua Yu

The pushover analysis had been done for a R.C frame model, vertex displacement、base shear 、 appear order and development situation of plastic hinges of the model had been get in different steps of pushover analysis, The pictures of basal shear-vertex displacement and response spectrum displacement-accelerated speed had been studied. The analysis results show that ,the R.C frame model correspond with the seismic design principle of stronger column weaker beam ’,and meet the seismic requirements of the first stage and the calculating resistance to collapse of the second stage.


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