Developing local rubber mixture for seismic base isolation system type high damping rubber bearing

Abstract

The research objective is to develop a rubber mixture for the High Damping Rubber Bearing HDRB type of seismic base isolation system to resist seismic loads, and compare it with international companies’ brochures. Experiments were conducted on three HDRB models of 150 mm in diameter and 12 cm in height. These models were manufactured locally from natural rubber with other chemical additives and steel sheets. Load and unload tests (quasi-static) were conducted on the models simulating earthquake loads, first loaded with a vertical load of 110 kN, and then the base cyclic horizontally with an increasing amplitude of 25 % until 125 % of the shear strain. The vertical stiffness was 44,027 kN/m, the effective horizontal stiffness was 334 kN/m, and the damping ratio was 20.1 % experimentally. The results were within satisfactory ranges of the parametric values in the manufacturing design brochure, indicating the developed rubber mixture is convenient, giving a great motivation to manufacture seismic isolators locally at suitable prices.