Research On Mechanical Behaviors And Design Of Integral Abutment Curved Box Bridge

The integral abutment curved box bridge (IACBB) is an innovative structurebased on the design concept of applying integral abutments to conventional curvedbox bridge. In this paper, the study on the concrete model test, mechanical behaviors,and core design details of IACBB were carried out for the first time in order tounderstand the mechanical behaviors of IACBB and demonstrate the feasibility ofengineering application of IACBB, providing guidance for engineering design. Theresults of research layed the foundation for engineering application. The mainresearch work and results were described as the followings:1．The experiment system was designed to simulate the soil pressure behindabutments and around piles of IACBB. Study on the model contrast tests of IACBB,conventional curved box bridge and curve rigid frame box–girder bridge were carriedout, the difference on the loaded behavior of the three structure were pointed out. Theresults of the test of ultimate bearing capacity of IACBB indicated that the failuremode of IACBB was different from the failure type of conventional bridge because itmay occur ultimate strength failure of abutments or local compression-bendingfailure of piles firstly, the corresponding design recommendations being put forward.2．Under the environment of general purpose program ANSYS and specialprogram COM624P V2.0, the finite element method for analyzing IACBB wasproposed and could become an effective method for the analysis of the innovativestructure.3. Taking a conventional curved box bridge with spans of4×25m as theprototype, the trial design on IACBB was presented and the baseline FE model of thetwo structure was made. The compute results indicated that the IACBB had excellentmechanical behaviors and potential prospect for engineering application. The twotype of bridge had obvious difference in mechanical behaviors (such as moment,torque, deflection and radial displacement of girder, etc).4．Based on the sensitivity analysis of parameter, important influencing factors on mechanical behaviors of IACBB were identified with temperature transformation,soil type behind abutment and around piles in load and restriction parameter andcentral angle, bridge length, bridge width, abutment height, pile length, pileorientation in structure geometry parameter. Furthermore, the suggestion aboutreasonable value range of parameter were put forward. The results of research shouldprovide design basis for engineering practice.5. From the view of the adverse changes in constraints condition at girder fringe,the cause and mechanism of slippage wreck of a certain bridge was illuminated andthe feasibility and validity of the integral abutment structure restrain similar wreckwere analyzed. The results of research provided a innovative idea and structureproject to avoid the similar wreck and to reinforce and rebuild the destroyed structure.Furthermore, it indicated that the IACBB had more widely application space.6. Research on the core details of conceptual design of IACBB, primary designparameter and reasonable design method and process were put forward. The resultsof study should provide reference for the application of actual bridge and thepreparation of design guidelines of IACBB.