Study Of Topology Optimization And Calculating Method Based On Space Truss Theory For Thick Pile Cap

With the rapid development of high-rise building, wharf, large bridge and main pylon project, pile foundation has been widely applied. In order to meet the capacity requirement and restraint to upper structure, the thick of pile cap is becoming more and more large. However, the thick pile cap itself has some shortcomings:its great weight, mass concrete hydration heat etc. In fact, by the force situation of the thick pile cap is very complicated, there are serious differences between the researchers. With the research for pile cap, space truss model can accurately reflect the load transfer mechanism of thick pile cap.The FEM software ABAQUS is adopted for the topology optimization analysis of the thick pile cap with three piles,four piles and six piles, the space truss model is obtained. The mechanical behavior is analysed based on the above study, the bearing capacity formula of diagonal struts is proposed. The main conclusions are as follows:1、The analysis of Finite Element shows that space truss model can accurately reflect the load transfer mechanism of the thick pile cap.We use concrete compressed struts represent the pressure flow which distribute in the range of column and pile, and tension rods represent the tension flow which distribute in the range of piles at the bottom of pile top cap.2、Verify the feasibility of the topology optimization theory in the research of thick pile cap.The space truss model of topology optimization shape is obtained by the evolutionary structural optimization(ESO) algorithm based on the strain energy criterion.3、By the analysis of a large number of experimental data and the exiting norms formula of pile caps, the study proposed bearing capacity formula of the concrete diagonal struts.4、Put forword the design method based on the space truss model of the thick pile cap, including the established principles, simplified model of the thick pile cap, and the steps of pile cap design.