scholarly journals Comparative seismic analysis study of G+ 20 story building with flat slab and conventional slab using ETABS

Author(s):  
Mr. Nitish A. Mohite

Abstract: In the study, three dimensional analytical models of G+20 story buildings have been generated and analysed using CSI ETABS software version 2016. The earthquake zone III in India is considered for buildings during analysis. Here, the analysis and design is done of G+20 story building with flat slab(with drops) and conventional slab system. In earthquake zone the displacement and drift of the structures will be more so to have more stiffness to the structure shear wall is to be provided therefore a study is made by comparing between conventional slab & flat slab (with drops) building. Comparison of various parameters like story drift, story displacement, story stiffness and time period is done. The equivalent static method is used to design and analyze the structures, as categorized by Indian Standard Code for earthquake resistant structures. The study shows that story drift is 10% more in conventional slab as compared to flat slab; story displacements is observed linearly increasing with height of the building and is 11% more in conventional slab as compared to flat slab . Keywords: Equivalent Static Method, Flat Slab, ETABS 2016, story displacement, story stiffness, story drift, time period

Seismic analysis of structure is employed to make the structure enable to resist the seismic forces and perform against the factors causing the failure of the structure under dynamic excitation. Among various response factors, the base shear and time period of buildings are predominant factors used in the analysis and design of the structure. The prime objective of the paper is to present an analytical study on non-linear seismic analysis of moment resisting framed buildings (as per Indian code IS1893 – 2016) to evaluate the base shear of different configurations of buildings according to different mode combination methods. The obtained results have been presented the comparative analysis of different combination methods. The paper also presents the evaluated results in the form of the time period values of the different buildings depending upon variation in its configuration. As a result, the responses of multistoried moment-resisting framed buildings have been evaluated for various models of considered buildings based on different mode combination methods, and the results of obtained responses have been analyzed in a comparative manner to understand the behaviour of buildings under various methods and configuration conditions. The work presented in the paper can support to develop better understanding of structural response and efficient designing of structures.


The offshore jacket platforms are primarily installed in the large oceans mainly for drilling the crude oil, carbohydrates and production of electricity. The current studies emphasize on the structural performance of offshore deck jacket platform with different bracing systems. Earthquake analysis has been performed to calculate the seismic responses, with the help of bracings to control the seismic induced vibrations of the jacket platforms. For this study, a jacket platform made up of steel members has been modeled and then analyzed under earthquake and wave loadings. This paper mainly deals to compute and compare the seismic behavior of offshore steel deck platform using SAP 2000 v20 software with bracing in the horizontal plane and bracing in both horizontal and vertical planes. The total number of 8 models has been analyzed in the SAP2000 software with bracing i.e. X, V, Inverted V and K in the vertical plane and bracing i.e. X, V, Inverted V and K in both horizontal and vertical plane. A relative study has been carried out in Time period, deck displacement and base shear. Seismic analysis using linear static, i.e. Equivalent static method (ESA) and linear dynamic, i.e. Response spectrum method (RSA) has been performed. Further deck displacement, time period and base shear are determined by Equivalent static method and Response spectrum method for various types of bracing models in both horizontal and vertical planes. Among the all various types of bracing models, Inverted V bracing in the vertical plane is found to be the optimum model among all other models.


The flat slab is a two-way reinforced concrete slab that usually does not have beams and girders, and the loads are transferred directly to the supporting concrete columns. ETABS automates several slab and mat design tasks. Specially, it integrates slab design moments across design strips and designs the required reinforcement; it checks slab punching shear around column supports and concentrated loads; and it designs shear link and shear stud if needed. The actual design algorithms vary based on the specific design code chosen by the user. This manual describes the algorithms used for the various codes. Recent earthquakes in which many concrete structures have been severely damaged or collapsed, have indicated the need for evaluating the seismic adequacy of existing buildings. About 60% of the land area of our country is susceptible to damaging levels of seismic hazard. Many existing flat slab buildings may not have been designed for seismic forces. Hence it is important to study their response under seismic conditions and to evaluate seismic retrofit schemes. This system is very simple to construct, and is efficient in that it requires the minimum building height for a given number of stories. Unfortunately, earthquake experience has proved that this form of construction is vulnerable to failure, when not designed and detailed properly, in which the thin concrete slab fractures around the supporting columns and drops downward, leading potentially to a complete progressive collapse of a building as one floor cascades down onto the floors below. Although flat slabs have been in construction for more than a century now, analysis and design of flat slabs are still the active areas of research and there is still no general agreement on the best design procedure. To study the effect of drop panels on the behavior of flat slab during lateral loads, flat plate system is also analyzed. Zone factor and soil conditions- the other two important parameters which influence the behavior of the structure, are also covered. Software ETABS is used for this purpose. In this study relation between the number of stories, zone and soil condition is developed.


2018 ◽  
Vol 13 (2) ◽  
Author(s):  
Dian Yuristia ◽  
Ririt Aprilin S ◽  
R. Eka Murtinugraha

The purpose of this research was to analyze soft second  story bulding behavior due to the earthquake load by applying column height variation. The building case has a vertical irregularity soft story on the second level so the behavior during the earthquake was analyzed by heighten the columns at the second level of the building. The behavior of building structure results the response such as internal forces in columns and beams, base shear, fundamental period, displacement and story drift. The seismic analysis is using dynamic analysis response spectrum based on SNI 1726:2012 and carried out using software ETABS version 9.7.4. The results of this research indicates that the increase of column height in soft second  story building reduces the building stiffness. So it decreases the building forces, extending the fundamental period, decreasing the base shear, increasing the displacement and the story drift. It can be concluded that the soft second  story building reduces the building resistance of earthquake load by produces the behavior approaches the collapse.


Author(s):  
Udaya kumar ◽  
◽  
Dr. Aravind Kumar B Harwalkar ◽  

The cold formed steel section are increasingly used as a structural elements in low rise buildings in recent times, due to the advantages like economic production, easy transportation, low labor cost and high strength to weight ratio. In the current work a G+3 storied building frame is studied for seismic and wind load using Staad-pro software. Light gauge section is taken for beam and slab elements. The seismic analysis is carried out by Equivalent static method. After analysis the results such as story displacement, story drift, Base shear and time period are compared for different models. The building frame is also analyzed for wind load. In the current work cross bracing using Light gauge element used as a retrofitting technique. The retrofitted building frame is analyzed for wind and seismic loads and results obtained for time period, storey displacement, storey drift and base shear values are compared with the corresponding values of base frame. The results of retrofitted frame showed shortening in time period, storey displacement and story drift values in X&Z directions indicating the increased ductility, Stiffness and strength of structure. Hence the proposed retrofitting technique could be believed to achieve success results in increased strength and ductility values required by wind and seismic loading.


Author(s):  
Bayi Bage

Abstract: ETABS Stand for Extended Three-Dimensional Analysis of Building systems. ETABS integrates every aspect of the engineering design process. In the present situations of construction industry, the buildings that are being constructed are gaining significance, in general those with the best possible outcomes which are referred to members like beams and columns in multi storeys R.C structures. This paper deals with the seismic analysis of regular B+G+26 story building with shear wall and G+B+10 Story building with different irregular shapes considering different shapes of shear wall at different locations has been carried out. Which can be done in ETABS taking all the considerations regarding codes and other factors into account. All the buildings were analyzed with the same method as stated in IS 1893-Part-1:2016. The effect of shear walls on lateral capacity of the building are examined because the seismic analysis of a frame depends upon the location and symmetry of shear wall. Present study shows the shear wall improves not only the lateral stiffness and strength capacity but also the displacement capacity of structure. Comparison of results been done of different models by comparing the parameters such as story drift, story displacement, story stiffness and base reaction. Therefore, as far as possible irregularities in a building must be avoided. But, if irregularities have to be introduced for any reason, they must be designed properly following the conditions of IS 13920:1993. The complex shaped buildings are now days getting popular, but they carry a risk of sustaining damages during earthquakes. Keywords ETABS Software; IS Code 1892-Part-1:2016; IS Code 13920:1993; IS Code 875-Part-1 and Part-2


2021 ◽  
pp. 875529302098196
Author(s):  
Siamak Sattar ◽  
Anne Hulsey ◽  
Garrett Hagen ◽  
Farzad Naeim ◽  
Steven McCabe

Performance-based seismic design (PBSD) has been recognized as a framework for designing new buildings in the United States in recent years. Various guidelines and standards have been developed to codify and document the implementation of PBSD, including “ Seismic Evaluation and Retrofit of Existing Buildings” (ASCE 41-17), the Tall Buildings Initiative’s Guidelines for Performance-Based Seismic Design of Tall Buildings (TBI Guidelines), and the Los Angeles Tall Buildings Structural Design Council’s An Alternative Procedure for Seismic Analysis and Design of Tall Buildings Located in the Los Angeles Region (LATBSDC Procedure). The main goal of these documents is to regularize the implementation of PBSD for practicing engineers. These documents were developed independently with experts from varying backgrounds and organizations and consequently have differences in several degrees from basic intent to the details of the implementation. As the main objective of PBSD is to ensure a specified building performance, these documents would be expected to provide similar recommendations for achieving a given performance objective for new buildings. This article provides a detailed comparison among each document’s implementation of PBSD for reinforced concrete buildings, with the goal of highlighting the differences among these documents and identifying provisions in which the designed building may achieve varied performance depending on the chosen standard/guideline. This comparison can help committees developing these documents to be aware of their differences, investigate the sources of their divergence, and bring these documents closer to common ground in future cycles.


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