Experimental research on orthotropic bridge deck with steel plate-polyurethane sandwich structure

The mechanical properties of a 3-span continuous orthotropic bridge deck with a steel plate-polyurethane sandwich structure were investigated by means of steel box girder model experiments for the bridge decks with two kinds of longitudinal stiffener spacings and by comparing with calculation results of steel box girder finite element models for the bridge deck with various stiffener spacings. The test model was made of the same material as its actual bridge and the geometrical dimensions of the box girder were reduced to 1/4. The strains in the length and transverse ways, and deflections of the cross section at key points were tested, as a truckloading is generating the maximum bending moment at the midspan as well as on the cross section at the supports. The results show that: test strain values of the bridge deck are basically agreed well with the calculated values. Using the orthotropic bridge deck with a steel plate-polyurethane sandwich structure can greatly reduce the peak value of a local stress concentration and thereby greatly reduce the quantity of a stiffening rib, and the decrease mainly depends on the sandwich plate thickness. Some positions of a sandwich bridge deck will bear an opposite stress sign in the two orthogonal directions, the maximum longitudinal stress is at the bottom of a middle stiffener in a corresponding cross-section. The stress and deflection growth of a sandwich bridge deck will increase with the decrease of its sandwich layer thickness.