Preflex Prestressing Technology on Steel Truss Concrete-Composite Bridge with Medium Span

Guangdong Qingqiyong bridge is a prefabricated steel truss-concrete composite continuous rigid frame bridge with a span arrangement of 41 m + 70 m + 41 m, to prevent cracks of concrete deck on the bridge pier top section, prestress tendons are usually arranged inside of the concrete deck, after the connection between deck panels and steel truss, prestress tendons are tensioned to make deck compressed, it has been proved that this conventional prestress method is tedious for construction and it also results in a significant loss of prestress. In addition, stress of the top chords in the pier top section is very small in all construction stages, mainly ranges from -60 MPa to 50 MPa, thus failed to make full use of its material properties; therefore, preflex prestressing technology of steel truss concrete composite bridge (PPSC in short) was put forward based on preflex prestressing technology, then the detailed analysis was conducted. To validate the feasibility of PPSC, another case study-Wanzhou Bridge was carried out. Results show that the PPSC technology is feasible and it can avoid the use of prestress tendon, simplify the construction, make deck panels get the expected compressive stress easily and make full use of steel properties.