EFFECT OF SHAPE ON SEISMIC RESPONSE OF A STRUCTURE (original) (raw)
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Effect Of Shape And Plan Configuration On Seismic Response Of Structure
International Journal of Scientific & Technology Research, 2015
Earthquake is a very important aspect to be considered while designing structures. Lot of work has been reported by many researchers who worked to study the effect of structures with irregular plan and shape. Being inspired from the work contributed in the study on effects of earthquake on irregular shaped building in plan, this paper presents effects of plan and shape configuration on irregular shaped structures. Buildings with irregular geometry respond differently against seismic action. Plan geometry is the parameter which decides its performance against different loading conditions. The effect of irregularity (plan and shape) on structure have been carried out by using structural analysis software STAAD Pro. V8i. There are several factors which affect the behavior of building from which storey drift and lateral displacement play an important role in understanding the behaviour of structure. Results are expressed in form of graphs and bar charts. It has been observed from the re...
Seismic Response of Irregular Structures
International Journal of Advance Research, Ideas and Innovations in Technology, 2021
The main objective of earthquake engineering is to analyse, design and build a structure in such a way that the damage to the structure and its structural component during an earthquake is minimized. A large number of papers have focused to study the effect of irregular structures. Being inspired from the work contributed in the study on effect of earthquake on irregular shaped building this research work presents effect of plan and shape configuration on irregular shaped structures. Building with irregular geometry responds differently against seismic action. Plan geometry is the parameter which decides its performance against different loading conditions. This research work aims to evaluate the behaviour of irregularity (plan and shape) on structure under seismic effect. To workout the performance of structure, equivalent static analysis and response spectrum analysis has been adopted. For achieving this objective by using structural based software ETABS 19. Estimation of response such as: lateral displacement, storey drift, and base shear are carried out. Based on these parameters we have compared response of each model. Results are expressed in form of graphs and bar charts. From research it is observed that to minimize the effect of earthquake simple plan and configuration like regular shape must be adopted at the planning stage.
Analytical Study on Seismic Performance of Plan Irregular Structures
2021
The buildings constructed in irregular configuration due to economical feasibility, land availability and other factors. From the observations of past earthquakes, a structure with regular configuration structures stay safe in Earthquakes than an structure with irregularities. Structures experience lateral displacements under earthquake loads. This work focuses on studying the various sorts of building irregularities possible and their behaviour during earthquake forces. The various structural behaviour parameters such as displacement, base shear, storey drift, moment, end forces etc., are needed to be studied. The structures are designed and analysed by Time History Analysis using STAAD.PRO V8i software. From this analysis the results obtained shows that the base shear was higher in regular structure but the load transfer was uniform throughout its height. The L shaped structure showed a least performance during an earthquake.
A Study on Seismic Performance of Various Irregular Structures
2021
The buildings constructed in the present scenario are mostly irregular in geometry and elevation for aesthetic view. These irregularities may also be due to economical feasibility, land availability and other factors. From the past earthquake, researches says that regularly configured structures stay safe in Earthquakes, but irregularly configured structures could not able to withstand effectively during an earthquake. Structures experience lateral deflections under earthquake loads. This work focuses on studying the various sorts of building irregularities possible and their behaviour during seismic forces. This study focuses on learning the parameters to be analysed while analyzing a structure for seismic force. The various structural behaviour parameters such as displacement, base shear, storey drift, stiffness, strength etc., are needed to be studied. Also to know the model analysis methods those are available for seismic analysis of a structure. Some model analysis methods are ...
SEISMIC ANALYSIS OF PLAN IRREGULAR BUILDING
IAEME PUBLICATION, 2018
At the Earth's surface, earthquakes manifest themselves by shaking and sometimes displacement of the ground. Earthquakes are the most undesirable and distressing of all natural calamities A building with discontinuity is subjected to concentration of forces and deformations at the point of discontinuity which may leads to the failure of members at the junction and collapse of building when the epicenter of a large earthquake is happened. Equivalent Static Analysis is the simplest method and is often used for low to medium-rise buildings with regular shapes. It involves assuming a static load equivalent to the maximum dynamic load that the building is expected to experience during an earthquake. This method is easy to perform but may not accurately capture the dynamic behavior of the building. Response spectrum analysis is a more advanced method that considers the building's dynamic response to a ground motion. This method uses a response spectrum to calculate the building's response to different frequencies of seismic waves. The aim of this project is to conduct a comparative study of the seismic analysis of plan irregular buildings. The study will involve the analysis of several building designs using different methods and tools. The primary objective is to evaluate the effectiveness of different seismic analysis techniques in predicting the behavior of plan irregular buildings under seismic loading. This project is concerned with the study of high-rise irregular building. The structural analysis of G+10 storied reinforced concrete regular and irregular frame building is done with the help of “2019-ETABS” software. Response Spectrum Analysis (RSA) has also been carried out in the study. This approach permits the multiple modes of response of a building to be taken into account.
The Seybold Report, 2022
The modern reports and research showed that the buildings with more irregularity are less safe in facing earthquakes. This study aims to study the behavior of regular and irregular building in seismic matter. Three irregular shapes (L-Shaped, T-Shaped and C-Shaped) having two types of plan irregularity (accidental torsion and reentrant corner) were compared with rectangular regular one in three seismic hazards (Low, Moderate and High). ETABS v19 is used to model and analyze 12 different models with 15-story and 20-story RC frame structures using dynamic response spectrum method to obtain the maximum displacement, story drift, maximum drift and accidental torsion committing to ASCE7-10 code. The purpose of the study is to alleviate the seismic risk on the irregular structures and make our buildings safer, less cost and more Sustainable. at the end, we provide a table to guide the architectural engineers choosing the best building configuration based on the area seismicity and seismic hazard in order to match the purposes and the structural design in addition to provide some solutions to avoid structural design problems. The results were as follow: In the 15-story RCC frame structures with special moment resisting frame, the L-Shaped buildings are not safe to use in high seismic hazard areas, and the T-Shaped buildings are not safe to use in low and high seismic hazard areas. In the 20-story RCC structures with special moment resisting frame, the L-Shaped buildings are not safe to use in high seismic hazard areas, and the T-Shaped buildings are not safe to use in all seismic hazard areas. The comparison between the irregular shapes and regular one was predicted in L-Shaped and T-Shaped building which have worse seismic behavior than regular shape, but the comparison with C-Shaped was different, the C-Shaped gave a better behavior compared to the rectangular regular building.
Seismic Behaviour of Plan Irregular Building –An Analytical Study
International Journal of Research in Engineering and Technology, 2015
Asymmetric buildings often undergo unfavorable seismic behaviour, which results the irregular concentration of plastic demand in limited or vulnerable portion of the structure and subsequently, invite the early collapse of the structure during seismic vibrations. L-shaped buildings are among those asymmetric structures which are commonly found in the form of school, office, commercial as well as residential buildings. Accordingly, an analytical study is performed to investigate the seismic behaviour of plan irregular buildings. Moreover, to understand the effect of length of projection of the structure on the dynamic characteristics, different projection length lead to different aspect ratios for the same building plan shape have been analyzed here. It is observed that variation in projection length of such buildings have significant effect on the dynamic characteristics. However, the seismic response of few L-shaped buildings are analyzed using nonlinear static method and results have been shown in terms of capacity curve, performance point, interstorey drift, column shear, and plastic hinge formation pattern. Seismic demands of asymmetric systems are found to be potentially high due to its asymmetric distribution of mass, stiffness and strength, which is one of the major sources of damage, as it causes torsional floor rotation.
Limitation of irregular structure for seismic response
Structural engineer's greatest challenge in today's scenario is constructing seismic resistant structure. Uncertainties involved and behaviour studies are vital for all civil engineering structures. To understand and find accurate result in provisions of drift, deflection and hinge of structure under seismic force, non Linear Static Analysis is commonly employed and this method of analysis is called Pushover Analysis. This method of analysis shows the base shear carrying capacity of a structure and performance level of each component of structure under various zones or different intensity of seismic force. The present study incorporates the non linear behaviour of irregular structures. Because of the constraints some of the structures are highly irregular as too long, and too tall. This study aims to identify the limitations of the too long and too tall structures using the software SAP 2000.
The Influence of L-Shaped Structures on their Behavior against Earthquakes
In this research, the effect of architectural plan or structural diagram on building behavior against earthquake with equivalent static and dynamic method sis evaluated and the results of the equivalent static and dynamic analysis as well as certain combinations of the equivalent static analysis values have been reviewed and compared. Then various types of irregularly L-shaped structures with different irregular ratios (different projections ratios) and at different heights of the model were analyzed by equivalent static and dynamic method. The rate of torsion in irregular buildings was the benchmark. The classification of the results of both of the equivalent static and dynamic analysis and their comparison showed that in regular buildings with the number of different stories. The values of the equivalent static torsion (at the critical extension) and the maximum dynamic torsion is almost the same but it is not the case in irregularly L-shaped structures. In irregularly L-shaped structures, if the number of building floors is modeled to be less than 5, a slight difference between values of the equivalent static torsion (at the critical extension) and the maximum dynamic torsion is considered to be abandoned to the extent that it can be ignored. But as the number of floors increases to the above limit, this variation of torsion from the two equations of the equivalent static and dynamic analysis increases and as the number of floors increases this difference increases. According to the results obtained in this research it is suggested that in the case of irregularly L-shaped structures, it would be possible to restrict the use of the equivalent static analysis method. It also seems that under certain conditions the maximum torsion values obtained from the dynamic analysis can be obtained by constructing suitable combinations of the torsion values obtained by static analysis in two main orthogonal directions.
Influence of Structural Irregularity in Plan Floor Shape on Seismic Response of Buildings
JES. Journal of Engineering Sciences
Buildings with irregularity in plan floors appears to be more susceptible to large deformations and damage when they are subjected to strong ground motion than those with regular plan floors due to the additional accidental torsional forces resulting from the existing eccentricity between the center of mass and center of rigidity of the resisting elements. The evaluation of seismic response of irregular buildings in plan is required in order to determine the seismic level of protection afforded to these buildings by new design provisions which have been introduced to Egyptian code (ECOL201)[15]. Therefore it is intended in the present study to evaluate the performance of gravity loaded irregular buildings in plan under earthquake excitation. The structural irregularities in plan were represented by ten irregular configurations to cover and model the torsional effects. A time history analysis with a peak ground acceleration of 0.25g was carried out for these ten models using finite element program SAP2000[16]. The numerical studies for different configurations of irregularity effect were clear in T-plan shape than others. The base shear induced in the perpendicular direction ranged between 40% and 80% of the base shear in the direction of the motion. The results declared the necessity of executing structural separation in these irregular buildings in plan to minimize the induced perpendicular base shear. Many conclusions are deduced and they are believed to be very helpful to the structural engineer in order to improve the knowledge of the subject and to avoid unintended consequences of ECOL.