Earthquake Engineering

By
Prof. A. B. Kawade, Mr. Abhijeet A. Sahane
Amrutvahini College of Engineering, Sangamner

Abstract
Major seismic events during the past decade such as those that have occurred in Northridge, Imperial Valley (May 18, 1940), California (1994), Kobe, Japan (1995), Turkey (1999), Taiwan (1999) and Bhuj, Central Western India (2001) have Continued to demonstrate the destructive power of earthquakes, with destruction of engineered buildings, bridges, industrial and port facilities as well as giving rise to great economic losses. Among the possible structural damages, seismic induced pounding has been commonly observed in several earthquakes. As a result, a parametric study on buildings pounding response as well as proper seismic hazard mitigation practice for adjacent buildings is carried out. Therefore, the needs to improve seismic performance of the built environment through the development of performance-oriented procedures have been developed. To estimate the seismic demands, nonlinearities in the structure are to be considered when the structure enters into inelastic range during devastating earthquakes. Despite the increase in the accuracy and efficiency of the computational tools related to dynamic inelastic analysis, engineers tend to adopt simplified non-linear static procedures instead of rigorous non-linear dynamic analysis when evaluating seismic demands. This is due to the problems related to its complexities and suitability for practical design applications. The push over analysis is a static, nonlinear procedure that can be used to estimate the dynamic needs imposed on a structure by earthquake ground motions. This project entitled “Seismic Pounding Effects in Buildings.” aims at studying seismic gap between adjacent buildings by dynamic and pushover analysis. A parametric study is conducted to investigate the minimum seismic pounding gap between two adjacent structures by response Spectrum analysis for medium soil and Elcentro Earthquake recorded excitation are used for input in the dynamic analysis on different models. Pounding produces acceleration and shear at various story levels that are greater than those obtained from the no pounding case, while the peak drift depends on the input excitation characteristics. Also, increasing gap width is likely to be effective when the separation is sufficiently wide practically to eliminate contact. The results of pushover analysis viz. pushover curves and capacity spectrum for three different lateral load patterns are observed to study the effect of different lateral load pattern on the structural displacement to find out minimum seismic gap between buildings.
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By
Nilesh M. Kashid, Pune, Maharashtra, India.

ABSTRACT
During the last few decades, earthquake engineering has undergone significant development. Initially, structures were designed without considering seismic loading. Later, it was observed that the structures designed for some lateral loads like wind etc. performed significantly well than those designed for gravity loading only. Hence, the importance of considering earthquake forces in the design process is realized and seismic resistant design became a practice. Further with the advent of time history analysis and better understanding of seismic response. The importance of ductility of structure is realized in resisting even higher seismic loads than the designed loads. The design base shear force is reduced by introducing a response reduction factor to consider an inelastic displacement capacity of ductile structure in dissipating the energy. Further, with more understanding of structural behaviour at micro-level or element level, the concept of “capacity design” was introduced and this forced to decide the required performance of the structure right at the design stage itself. Today, the seismic design codes of various countries are being revised to decide performance criteria of the buildings that will suit the existing design and construction practices in the respective countries. In this paper, an attempt has been made to develop a possible method of seismic analysis that can be incorporated in the existing Indian Seismic Code I.S.: 1893-2002. For the purpose, some of the key features the existing methodology followed by Federal Emergency Management Agency (FEMA) of United States of America is made use of.

KEYWORDS: FEMA, performance point, displacement ductility ratio, inelastic displacement demand ratio, capacity curve.

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An approach on how to counter the damages caused by the earthquake in high risk areas of Pakistan.

Abstract
An applied study on different types of construction techniques in order to make a structure complaint and be able to withstand lateral forces lateral forces.
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