• Version
• Download 13
• File Size 302.55 KB
• File Count 1
• Create Date 4 June 2023
• Last Updated 4 June 2023

A REVIEW PAPER ON COMPARATIVE ANALYSIS OF RC STRUCTURE WITH AND WITHOUT OUTRIGGER USING STEEL BRACING

Snehal S. Khobragade , Prof.Kirti Padmawar

M tech Structural Engineering, Department of Civil Engineering, Ballarpur Institute Of Technology, Bamni, Chandrapur,442401,India

.snehalkhobragade1999@gmail.com

---------------------------------------------------------------------***---------------------------------------------------------------------

Abstract:

Tall building development has been rapidly increasing worldwide introducing new challenges that need to meet through engineering decision. As the height of the structure increases the stiffness of the structure reduces. Hence to develop the performance of the structure under seismic loading, outrigger system is proposed in the current study of work. This system is commonly used as one of the structural system to effectively control the excessive drift due to lateral load, so that during small or medium lateral load due to either wind or earthquake load, the risk of structural and non-structural damage can be minimized. In the current work, contain a comparative study on regular building with and without outrigger and irregular building with and without outrigger with centrally rigid shear wall and steel bracings as outrigger. The modeling of the structure is done using “ETABS” program. The analysis of the model is carried out by equivalent static method and response spectrum method. The stiffness and efficiency buildings characteristics of the structure is measured in terms of lateral displacement, drift, base shear and fundamental natural period for different types of buildings to provide stiffness against static and dynamic loads. The parameters should be minimized to prevent damage to the. In this paper, the effect of outrigger on key seismic design parameters of tall buildings with braced or shear wall core is studied. Based on the results of modal response spectrum (MRS) and nonlinear time history (NLTH) analyses of 44 models with braced or wall core, discussed in the companion paper and pushover analysis and presented in this part, the effect of outrigger and its placement level on parameters of seismic design including response modification factor R, overstrength factor Ω0, deflection amplification factor Cd, and damping ratio of structures are studied. New local measures for Cd and Ω0 are proposed based on the NLTH results. It is observed that outrigger results in greater increase in strength and stiffness of structures with wall core than buildings with braced core, but decreases the ductility of both systems. The obtained R is less than the values given by the code in most cases. For the main structures without outrigger, using the code prescribed value for Cd underestimates the real displacement of the structures with wall core and overestimates it for those

with braced core. Outrigger results in increasing Cd of structures with braced core and reduction of Cd in those with wall core. The considerable variation of two proposed measures for Cd shows the inappropriateness of application of a single value of Cd for all stories. Outrigger increased the damping ratio of buildings with shear wall core considerably.