Experimental study of a new assembled integral concrete–steel open-web sandwich plate composite bridge

This study introduces a new type of bridge structure—the assembled integral concrete–steel open-web sandwich plate composite bridge (COSPB), which is composed of a concrete slab,steel Vierendeel beams (SVBs, with top chords, bottom chords and shear keys), and studs (used for connecting SVBs and concrete slab). The bi-directional SVBs form a spatial steel grid structure, which can be used as the formwork for concrete slab casting, and divided into prefabricated units to allow on-site assembly after prefabrication in factory, leading to the reduction of on-site construction workload and the acceleration of the construction schedule. To understand the flexural behavior of this kind of structure, a static experiment was conducted on a 10-m-span full-scale test specimen with simply supported boundaries to investigate the deflection, strain distribution, and failure mode. The test results showed that there was still a large safety reserve for the flexural capacity of the section after the bottom chord of the steel–concrete composite Vierendeel beam (SCVB) began to yield. The ratio of the ultimate load to the yield load was 1.56. No concrete crushing and large area cracking were observed during loading, and the structure had good ductility. The ultimate flexural capacity of the SCVB was analyzed by the method of cross-sectional analysis, and the results were in good agreement with the test results. Finally, based on the test results, the ultimate flexural capacity and stiffness of the bridge were discussed using the Chinese Highway Bridge Design Code.