Structural behavior of lightweight reinforced concrete columns exposure to eccentric loads at high temperature

Abstract

This paper presents an experimental investigation on the behavior of six reinforced concrete columns under elevated temperature. An expanded clay aggregate (LECA) was used in three reinforced concrete columns ,other three remain columns used natural aggregate .All RC columns have similar cross sectional dimensions of 150mm ×150 mm (width× height); and 1250mm total length. The columns were designed according to ACI Committee 318-2014 and exposed to different elevated temperatures of 400 oC and500 oC. After exposure to elevated temperature, the columns were axially loaded by compression force using an eccentricity ratio (e/h) equal to 0.5. The experimental test results demonstrated a remarkable decrease in the ultimate carrying capacity of the columns when subjected to elevated temperature. The experimental test results have also revealed that the lightweight reinforced concrete columns have more fire resistance than the normal weight reinforced concrete columns under same elevated temperature. The ultimate load capacity of LWRC columns decreases by about 6.5 % ,and 14.286 %, at elevated temperature magnitude of 400 ºC, and 500 ºC respectively, compared with the control column at ambient temperature. However, the ultimate load capacity of NWRC columns decreases by about 14.15 %,and 28.571 %, at elevated temperature magnitude of 400 ºC, and 500 ºC respectively, compared with the control column at ambient temperature.