Behaviour of strut-waler connections with different stiffening details

Strut and waler are key components of the steel strutting system commonly found in steel temporary works for braced excavation in cut and cover tunnel, underground station and basement construction. In Singapore, the Nicoll Highway Collapse investigation has identified the stiffened strut–waler connection as a key cause of the catastrophic collapse of a section of the cut and cover tunnel construction for the Island’s Circle Line mass rapid transit system. This paper looks at the behaviour of the strut–waler connection formed typically from steel H-sections and influence of its various stiffening details. Finite element analyses of the stiffened connections comprising steel plates, channels and concrete infills are carried out, and their load resistances and post-peak behaviours are evaluated. It is concluded that conventional plate stiffeners are still the best for stiffening strut–waler connections.

S. P. Chiew, PhD, FIStructE, MIES, MASCE

Y. Yu, BEng, MEng
School of Civil and Environmental Engineering, Nanyang Technological University, Singapore