Residual Static Load Bearing Capacity of Orthotropic Composite Bridge Deck After Fatigue Loading

Abstract:

The ultimate bending capacity of two full-scale steel-concrete composite bridge decks were tested to study the residual bearing capacity of the high-performance concrete composite bridge deck after fatigue loading. A full-scale static-loading test was carried out for researching the static behavior of the orthotropic composite bridge deck， including the strain of concrete and steel bars， the deformation of the structure and the development of cracks. The test results prove the failure mode of the orthotropic composite deck to be a flexural failure. When the ultimate strength on the specimen reaches， the U-rib of the middle fulcrum section is buckling， and the tensile steel bars are yielding. The concrete in the negative bending moment area is seriously cracked， and the specimen has obvious deformation. Meanwhile， a flexural failure also appears on another bridge deck specimen after fatigue loading ， and the residual bearing capacity decreases by about 11.6% in comparison with the specimen without fatigue loading. Based on the bond-slip theory of reinforced concrete， a formula for calculating the average crack spacing of orthotropic composite bridge decks after fatigue loading is deduced. Compared with the test results， the proposed formula for calculating the average crack spacing has good accuracy， and the relevant research results can provide theoretical reference for practical engineering applications.

Key words:composite bridge deck;high performance concrete;experimental study;fatigue