International Journal of Advanced Structures and Geotechnical Engineering ISSN 2319-5347, Vol. 03, No. 04, October 2014 IJASGE 030412 Copyright © 2014 BASHA RESEARCH CENTRE. All rights reserved Study of Different Techniques in Design of Earthquake Resistant Structures SUCHITRO BASU, SWAGATO DAS, PURNACHANDRA SAHA School of Civil Engineering, KIIT University, Bhubaneswar, Odhisa, India Email: suchitro.basu@gmail.com, swagatodas83@gmail.com, dr.purnasaha@gmail.com Abstract: Seismic resistant structures are designed in such a way that they might face partial damage, but will not totally collapse during earthquakes. This design of structures depends on certain parameters like ductility, deformation capacity, strength and amount of deflection. More the ductility, strength and deformation capacity of a structure better will be its seismic resistance, whereas, lesser the amount of deflection, lesser will be the vulnerability of the structure towards earthquakes. This paper deals with the review of various techniques applied in the design of earthquake resistant structural frames without using any external seismic control device. These techniques include the use of smooth rebars and corrosion resistant hybridized columns in construction of Reinforced Concrete (RC) structures, installation of exterior shear walls to the structural frames, construction of brace framed steel structures and construction of composite structures. Smooth rebars when used for construction of RC structures provides good yield strength to the structure. Similarly when corrosion resistant hybridized columns are used in construction, it provides a high ductility and deformation capacity to the RC structures. Installation of exterior shear walls to both RC and steel structures increases their strength by 10%. For steel structures, construction of brace framed structures provides 5% more strength, and they are also seen to deflect less during earthquakes. Thus we see that in both RC and steel structures, innovative design techniques are implemented to make them seismic resistant. Keywords: Braced frame, composite structures, concentric braces, ductility, rebar, shear wall, Introduction: Earthquake which is defined as ground motion caused by a sudden movement of the Earth’s tectonic plates, do not cause loss of lives, but the structures resting on the earth surface, experience ground motion and hence undergoes damage or may totally collapse. This leads to loss of lives and enormous loss in property which ultimately leads to economic loss in a country. Since earthquakes cannot be predicted, structures are made resistant in such a way that they might undergo partial damage but will not totally collapse during an earthquake. Apart from strength and deformation capacity, earthquake resistant design of structures also focuses on ductility, which is an ability of a structure to face huge plastic deformation without loss in strength. This can be achieved by making sure that the available ductility is more than the required ductility[1, 2]. Structures are generally made up of a combination of flexible and stiff parts. This ensures that the seismic energy passed on to the structure is first absorbed in the flexible part and then gets transferred onto the stiff part [1, 3]. During an earthquake, the columns of the structures act as primary members which resist the seismic forces, owing to this fact it is seen that the use of corrosion resistant hybrid columns in Reinforced Concrete (RC) structures can reduce the residual displacement and also have enough energy dissipation capacity during earthquake excitations [4]. It is also seen that in areas of high seismic risk RC wall frame structures are constructed as it provides stiffness to the system’s lateral force resistance, and also behave as ductile structures [5]. In case of steel structures, Steel Plate Shear Walls (SPSW) and Buckling Resistant Braces (BRB) are used for the design of earthquake resistant steel structures. SPSW are designed to provide better diagonal tension yield for dissipation of seismic energy, whereas BRB are special braces which give full axial yield strength both in compression and tension. Both of them are highly ductile in nature and hence provide large stiffness which limits the structural damage during earthquakes [6]. The main objective of this paper is to review the various techniques used in earthquake resistant structural frames without using any seismic control devices. Seismic Effects on Structures: When earthquake excitations occur it transmits seismic waves which in turn cause ground motion of the earth’s surface. As structures rests on the earth surface, this ground motion is also passed onto them. The base of the structure moves with the ground but the roof tends to retain its position. But the roof is also forced to move as the walls and columns of the structure are connected. Under this condition, the structures generally tend to collapse or undergo brutal damage. This can be prevented if the structure is ductile. Ductility is defined as an ability of a structure to face huge plastic deformation without loss in ultimate strength. The ductility of a structure enables to predict the amount of seismic energy that may be dissipated through plastic deformations, which is a very important factor for structural design under seismic loads [2, 7]. Therefore we see that seismic resistant design of structural frames depend upon