Construction and load rating of a large capacity reaction floor-wall assembly for lateral load testing at IIT Kanpur

Abstract

The earthquake simulation on full-scale civil engineering structures under quasi-static lateral loading environment provides an affordable and practical means to understand the nonlinear behavior of structures and their seismic energy dissipation potential. The required experimental facility consists of a large capacity strong floor and wall reaction assembly along with servocontrolled electro-hydraulic actuators for the load application. One such testing facility is nearing completion at IIT Kanpur, which has 15 m×10 m L-shaped and 10.5 m high reaction wall and 1.2 m thick top slab of the box girder for the strong floor. The anchor points are located in the wall and floor in a square grid of 0.6 m with each point has load capacity of 1.7 MN in tension and 1.0 MN in shear. The 2 m thick post-tensioned wall using Freyssinet 12K15 cable system in a novel configuration can resist an overturning moment of 12.7 MNm per meter of the wall. The capacity of the reaction assembly depends upon number of loads applied, combination of loads, and interaction between different components of the reaction assembly structure. A methodology based on “influence coefficients” was developed to estimate the worst load combination for describing the load rating of the reaction structure. Finite element analyses in Abaqus environment was conducted to compute the influence coefficients matrix whose elements can be added linearly to find out the maximum loading effect on the structure which can be used to determine the limiting load for a particular case of load application.