NONLINEAR SEISMIC ASSESSMENT OF COUPLED WALLS DESIGNED IN ACCORDANCE WITH EUROCODE 8

Abstract

Experience from previous earthquakes have shown that wall structural systems experience less damage during earthquake compared to frame systems. Wall systems for functional and architectural reasons frequently have openings (windows, doors, elevators, esc.). Wall systems with regularly distributed openings represent efficient system for resisting earthquake loads. Coupling beams connecting the walls, if designed and detailed properly, increase seismic resistance of the building by distribution of inelastic deformations both vertically and in plan. Eurocode 8 introduced set of rules for design and detailing of coupled walls and coupling beams. In order to access performance of coupled walls and beams designed in accordance with EC8, linear and nonlinear analysis of 11 story building was performed. Linear elastic modelling was done using software for linear analysis. The walls and coupling beams were designed and detailed in accordance with the provisions of Eurocode 8, part 1. Nonlinear model and assessment of inelastic response was conducted using Perform 3d CSI software for nonlinear analysis. For the modelling of coupled walls, wall section with fibers is used. The confined constitutive relationship is used for concrete edge elements, and unconfined relationship for concrete for the rest part. The reinforcement constitutive model was defined with bi-linear curve. Coupling beams are modelled using frame elements with shear hinge elements. Deformation capacities of elements was defined in accordance with EC8 provisions. Considering that EC8 doesn’t provide provisions for deformation capacities of diagonally reinforced coupling beams, deformation capacities for these elements is defined in accordance with the provisions of ASCE 41-06 standard. Static nonlinear analysis is performed in accordance with EC8 provisions and deformation capacities of wall elements and coupling beams checked in accordance with the provisions EC8 part 1 and part 3, where applicable. Characteristic results are presented on the end of paper, with conclusions and recommendations.