Neha M. Mevada et al.Int. Journal of Engineering Research and Applications www.ijera.com ISSN: 2248-9622, Vol. 6, Issue 5, (Part - 2) May 2016, pp.76-85 www.ijera.com 76|Page Seismic Response of Adjacent Buildings Connected With Non- linear Viscous and Viscoelastic Dampers Neha M. Mevada 1 , Snehal V. Mevada 2 and Sumant B. Patel 3 1 P.G. Student, 2 Assistant Professor, 3 Associate Professor,Structural Engineering Department,Birla Vishvakarma Mahavidyalaya (Engineering College), Vallabh Vidyanagar-388120, Gujarat, India. ABSTRACT Connecting the adjacent buildings with dampers not only mitigates the structural response, but also avoids pounding. In this paper, the seismic response of two adjacent single storey buildings of different fundamental frequencies connected with various types of dampers under different earthquake excitations is studied. A formulation of the equations of motion for model of buildings connected with dampers is presented. The seismic response of the system is obtained by numerically solving the equations of motion using state-space method. The effectiveness of various types of dampers, viz., non-linear viscos and viscoelastic dampers in terms of the reduction of structural responses (i.e., displacements and accelerations) of connected adjacent buildings is investigated. A parametric study is also conducted to investigate the optimum damping coefficient of the dampers for adjacent single storey connected buildings. Results show that connecting the adjacent single storey buildings of different fundamental frequencies by these dampers can effectively reduce the earthquake induced responses of either building. There exist optimum damper coefficients for minimum earthquake response of the buildings. Keywords:Adjacent connected buildings, Non-linear viscous dampers, Optimum, Seismic response, Viscoelastic dampers. I. Introduction Structures are often built close to each other because of lack of available land in metropolitan cities. To reduce the response of the structure to earthquake excitations, various types of control system devices have been proposed for adjacent buildings. One of the methods to mitigate structure system response is connecting adjacent buildings with dampers. The ground motions during earthquakes cause damage to the structure by generating inertial forces generated by the vibration of the building masses. Tall structures are more vulnerable to the structural damage because the masses at the levels are relatively large, supported by slender columns. The displacement of the upper stories is very large as compared to the lower ones. This includes large shear forces on the base columns. If the separation distances between adjacent buildings are not sufficient, mutual pounding may also occur during an earthquake as observed in the 1985 Mexico City earthquake, the 1989 Loma Prieta earthquake, and many others. To reduce the seismic responses of buildings, adjacent buildings are linked together by connecting dampers, such as the Triple Towers in Downtown Tokyo (Asano et al., 2003, Yang and Lam, 2014). Researchers have proposed different types of connecting devices to connect adjacent buildings. The connecting devices include passive dampers (Bhaskararao and Jangid, 2006; Xu et al., 1999a, b; Zhang and Xu, 2000), active dampers (Christenson et al., 2003; Zhang and Iwan, 2003) and semi- active dampers (Bharti et al., 2010; Christenson et al., 2007; Xu and Ng, 2008). To prevent mutual pounding between adjacent buildings during an earthquake, Westermo(1989) suggested using hinged links to connect two neighbouring floors if the floors of adjacent buildings are in alignment. It is observed that the system can reduce the chance for pounding, but it alters the dynamic characteristics of the unconnected buildings, enhances undesirable torsional response if the buildings have asymmetric geometry, and increases the base shear of the stiffer building. Luco and Barros(1998) studied the optimum values for the distribution of viscous dampers connecting two adjacent structures of different heights. Under certain conditions, apparent damping ratios as high as 12 and 15 percent can be achieved in the first and second modes of lightly damped structures by the introduction of interconnected dampers. Zhang and Xu (1999)investigated the dynamic characteristics and seismic response of adjacent buildings linked by viscoelastic dampers and it is showed that using the dampers with proper parameters to connect the adjacent buildings can increase the modal damping ratios and reduce the seismic response of adjacent buildings significantly. Hongping and Hirokazu(2000)studied the seismic response of two RESEARCH ARTICLE OPEN ACCESS