Behaviour and Strengthening Methods of Tall Slender Columns in Earthquake Conditions

Abstract

Reinforced concrete buildings are normally designed and constructed with well-defined vertical column supports which are able to withstand both vertical and lateral loadings. In the case of high columns there is a risk of instability due to its slenderness caused by the higher apex ratio (measured by its height in relation to the width). This is compounded by having such buildings located at medium to high seismic risk zones, where lateral dynamic loadings can occur. This research paper focused on how such slender reinforced concrete columns will behave under earthquake loading conditions, and highlights some innovative ways to strengthen the column capacity to withstand both vertical and lateral loadings. Besides the conventional ways to provide diagonal or lateral bracings, the use of glass fibre reinforced polymer (GFRP) as an alternative material for retrofitting tall slender reinforced concrete columns are presented here. The new method includes spraying of the GFRP onto the external surfaces of the columns and also incorporate the GFRP bars as additional reinforcement into the concrete columns. Both methods proved to improve the durability and strengthen the tall reinforced concrete column. This study shows the ability of the new method of amelioration of the slender reinforced concrete columns to increase their stability during seismic activity.