| Abstract:As a long-term load, creep has effect on mechanic behavior of concrete filled steel tubular arch bridge. The creep deformation of the core concrete will cause redistribution of internal force in the section and make steel tube yield in advance, further will increase the deflection of the arch ring and reduce the stability of the bridge. Therefore, the research of creep’s effect on ultimate capacity of concrete filled steel tubular is investigated in this paper. The main contents and achievements are as follows:(1) The analysis methods for ultimate bearing capacity under the creep effect in ANS YS software is summarized, and the creep effect of ultimate bearing capacity of concrete filled steel tube arch bridge is analyzed by fitting corresponding metal creep formula of core concrete or defining stress-strain curve considering the effect of long-term load.(2) Based on creep test of the concrete filled steel tubes under long-term loadings, the creep model of core concrete is proposed and fitted. Further the high precision of the fitted creep model is verified by the test results. The elastic theory of aging and the plastic flow theory are adopted to calculate the creep of concrete filled steel tube.(3) The creep effect of arch rib’s ultimate bearing capacity for singular steel tube is analyzed by different parameters such as steel ratio, slenderness ratio, steel type and loading type. The results show that the creep effect will lead to the reduction of ultimate bearing capacity by14%-46.71%after10years.(4) The ultimate bearing capacity of concrete filled steel tubular arch bridge will decrease due to creep effect. Taking the Maocaojie Bridge as an engineering example, the ultimate bearing capacity (i.e. the live load ratio) decreases by15%due to creep effect after10years. |
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