Structural Behaviour of a Stressed Arch Structural System

摘要

The report describes a structural system consisting of plane arched trusses composed of fold-formed circular and square hollow sections. The unique feature of the structural system is the way the arches are erected without the use of cranes or scaffolding but by the use of a post-tensioning process. A prestressing cable passing through the bottom chord of the truss is stressed so that predetermined gaps in the bottom chord close to allow the chord to shorten, thus producing upward curvature of the truss into an arch shape. During the uplift of the truss, the top chord is curved in negative bending. For some highly curved structures, the top chord may be plastically deformed during the erection procedure. In addition, the top chord must support the axial compressive force in equilibrium with the tendon force in the bottom chord. The report describes a series of tests which were performed on sub-assemblages of the stressed arch to determine the effect of the negative curvature of the top chord on its axial capacity.