Full scale testing of steel arch tunnel supports

The results of a testing program comprising five full scale tunnel steel arch supports are reported. The arches, made from RSJ, were tested by jacking the arch legs against blocking points located along the crown of the arch. The number as well as the positions of the blocking points were varied in an effort to simulate various roof loading conditions and constraints. A nonlinear finite element modelling technique was applied to simulate the tested arch supports. Comparison of the ultimate strengths obtained from numerical predictions and experimental results show good agreement. It is found from both the experimental and the numerical modelling work carried out that increasing the number of blocking points causes a substantial gain in the load carrying capacity of the arch support.