IJE TRANSACTIONS B: Applications Vol. 33, No. 2, (February 2020) 205-212 Please cite this article as: S. P. Challagulla, C. Parimi, S. C. Mohan, E. Noroozinejad Farsangi, Seismic Response of Building Structures with Sliding Non-structural Elements, International Journal of Engineering (IJE), IJE TRANSACTIONS B: Applications Vol. 33, No. 2, (February 2020) 205- 212 International Journal of Engineering Journal Homepage: www.ije.ir Seismic Response of Building Structures with Sliding Non-structural Elements S. P. Challagulla a , C. Parimi a , S. C. Mohan a , E. Noroozinejad Farsangi* b a Department of Civil Engineering, BITS-Pilani, Hyderabad, India b Faculty of Civil and Surveying Engineering, Graduate University of Advanced Technology, Kerman, Iran PAPER INFO Paper history: Received 13 December 2019 Received in revised form 01 January 2020 Accepted 17 January 2020 Keywords: Primary Structure Secondary Bodies Coulomb Friction Sliding Effect Seismic Hazard Level ABSTRACT Interaction between a structure under base excitation and heavy non-structural elements that it supports is significant in the seismic analysis and design of the structure. Heavy non-structural elements may slide/rock under base excitation, and this dynamic action affects the seismic behavior of the supporting structure. Hence, in this study, a numerical model was presented to describe the seismic behavior of a primary structure (PS) supporting non-structural elements referred to as secondary bodies (SBs). The governing equations of motion for PS and SBs were developed considering Coulomb's friction model. Seismic hazard levels corresponding to Indian seismic zone III (medium hazard level) and V (highest hazard level) were considered. A parameter called displacement ratio (DR) was defined to quantify the sliding effect of SBs on the displacement response of the PS. A parametric study has been conducted to understand the variation in the DR due to varied time period of the structure, live loads to structure mass ratios and coefficients of friction between PS and SBs. From the analysis of results, it was concluded that the DR varies significantly with the time period, mass ratios, and coefficient of friction values. It can also be found from the study that the energy dissipation due to sliding of SBs was more in the highest hazard level than medium hazard level. Finally, the conditions for which the full mass of sliding secondary bodies should be considered in the seismic design of the structure are also presented. doi: 10.5829/ije.2020.33.02b.04 NOMENCLATURE PS Primary structure   Structural period (s) SBs Secondary bodies k Lateral stiffness of the Primary structure (N/m) DR Displacement Ratio c Damping coefficient (N-s/m)   Mass of the Primary structure (kg) Greek Symbols   Mass of the ith secondary body (kg)   Static coefficient of friction between PS and ith SB   Ground displacement (m)   Kinematic coefficient of friction between PS and ith SB   Displacement of the Primary structure (m)   Mass ratio of the ith secondary body   Displacement of the ith Secondary body (m) 1. INTRODUCTION 1 Damage to non-structural elements (NSEs) can occur even at low levels of ground shaking [1]. Non-structural elements whose anchorage mechanism is not proper or with no anchorages are more vulnerable to earthquakes [2, 3]. Sliding of such NSEs can result in economic loss and injury. The literature on these types of NSEs ranges from the closed-form and numerical solutions describing the sliding displacement of NSEs under base excitations *Corresponding Author Email: noroozinejad@kgut.ac.ir (E. Noroozinejad Farsangi) [4-6]. Sliding of heavy NSEs may affect the structural response of the structure, and hence their interaction must be considered [7]. Sliding displacements of elements are very sensitive to the coefficient of friction [8]. The reduction in the displacement of the structure with sliding live load during seismic events has been confirmed in the previous studies [9-11]. In the event of a major earthquake, the NSEs will slide when the inertial force of the load exceeds the friction force, and some part of the seismic energy of the structure is dissipated by the