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International Research Journal of Engineering and Technology (IRJET)

e-ISSN: 2395-0056

Volume: 10 Issue: 07 | July 2023

p-ISSN: 2395-0072

www.irjet.net

SEISMIC ANALYSIS OF HYBRID STRUCTURAL CONTROL SYSTEM IN RC BUILDING Parth J. Chavda1, Deepa H. Raval2 1 P.G. Student, Applied Mechanics Department, L.D. College of Engineering, Ahmedabad, Gujarat, India.

2 Assistant Professor, Applied Mechanics Department, L.D. College of Engineering, Ahmedabad, Gujarat, India.

---------------------------------------------------------------------***--------------------------------------------------------------------1.1 STRUCTURAL CONTROL

Abstract - Present study addresses to investigate effect of

lead rubber bearing (LRB) isolation system in combinations with fluid viscous damper as an energy dissipation device in high rise RC building to study the effect of seismic isolation on structural response/behaviour under seismic loading. The effect of change in building height as 60m, 105m and 150m and location of isolators (at base and one-fifth of the building height) have also been investigated. For that fluid viscous damper (FVD) as an energy dissipation device and lead rubber bearing (LRB) as a base isolator and inter storey isolator were considered. The first case was the fixed-base (FB) building, the other three cases were the single use of FVD, LRB at base and at one-fifth of the height of building and the last two cases were included the upgrading of the building with the combination of FVD with LRB base isolation and inter storey isolation systems. The effectiveness of the lead rubber bearing (LRB) isolation systems together with the fluid viscous dampers (FVD) was investigated. They were modelled using a finite element program, and evaluated by the nonlinear time history analyses in which three ground motion records s 2001 Bhuj, 1940 and EL Centro were adopted. Time history Analysis was carried using ETABS software. This study includes comparisons of the seismic response parameters such as time periods, storey displacement, storey drift and storey shear and storey overturning moment for the different proposed structural control systems.

Structural control means to improve performance of structure in order to minimize structural damage. The structural control system is also known as earthquake protective systems. Control systems which develop controllable forces to dissipate energy in a structure by increasing/modifying stiffness or/and damping to improve structural dynamic properties. Control systems are also force actuation devices integrated with sensors, controllers and real-time information processing. It is the fact that the earthquake can be accepted as the most devastating disaster because it causes many injuries, fatalities, and severe damage to the public buildings and bridges. In the last three decades, there has been great deal of interest in the use of control systems to mitigate the effects of dynamic environmental hazards like earthquake and strong winds on the civil engineering structures.

Key Words: Base isolation, Inter-storey isolation, Lead rubber bearing, Fluid viscous damper, Time history analysis

Fig -1: Structural Control Systems

1. INTRODUCTION

1.2 BASE ISOLATION

Civil engineering structures located in environments where earthquakes or large wind forces are common will be subjected to serious vibrations during their lifetime. These vibrations can range from harmless to severe with later resulting in serious structure damage and potential structural failure. In such area design of the structure should be done in such a way that we get proper safety of our structure in a hazard condition and to ensure the functional performance of flexible structures against such undesirable vibrations, various design alternatives have been developed, ranging from alternative structural systems to modern control systems with the use of various types of protective devices. Present study aims to investigate effect of lead rubber bearing (LRB) isolation system in combinations with viscous damper as an energy dissipation device in high rise RC building.

The principle of Seismic Isolation is to introduce flexibility at the base of a structure in the horizontal plane, while at the same time introducing the damping elements to restrict the amplitude of the motion caused by the Earthquake. The system operates by decoupling the structure from the horizontal components of earthquake ground motion by interposing a layer of low horizontal stiffness between structure and foundation. The flexible pads are called base-isolators, whereas the structures protected by means of these devices are called base-isolated buildings. If the flexible pads are properly chosen, the forces induced by ground shaking can be a few times smaller than that experienced by the building built directly on ground, namely a fixed base building.

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