Scaffolding bracing of composite bridges during construction

Relatively little bracing of steel girders can significantly reduce possible risk of buckling failures, before the composite action between steel and concrete occurs. This paper intended both experimentally and numerically, to study the torsional bracing performance of a typical type of scaffoldings commonly used in bridge construction. Minor improvements in the structure of the scaffoldings as well as at their connections with steel girders were needed for this purpose, which are shortly discussed in this paper. In the numerical investigations, the effects of different initial imperfections on bracing properties of the scaffoldings were also investigated. The study was extended to different bridge lateral torsional buckling slenderness ratios, and geometries. Results showed that the proposed system greatly increased the load carrying capacity of the studied bridges with consideration of lateral torsional buckling during construction phase. Brace forces created in the scaffolding trusses were also measured both in the experimental and in the numerical investigations. Finally, indications of brace moment versus in-plane moment values for different magnitudes of initial imperfections and lateral torsional buckling slenderness ratios were given