Study On The Coupling Of Meshless Methods To Finite Element Methods About The Ribbed Raft On The Winkler Foundation

The raft foundation is one of widely used foundation forms under the multilayer andhigh-rise construction. In order to reduce the construction cost, or increase the rigidity of theraft foundation, the ribs are added on the raft foundation. It is called the ribbed raft foundation.As the information that we have collected indicates, there are few methods to compute theribbed raft foundation. In this paper, the element free methods are coupled with the finiteelement methods to analyze the ribbed raft on the Winkler foundation.The finite element methods have been the important element of the fields of project andscience and influenced every embranchment of them deeply. In the recent years, the elementfree methods as a type of new numerical analysis methods are developed rapidly. They cansolve the problems that the traditional methods can't do them successfully and have obtainedmuch attention in the field of international computation mechanics.The main researches of this paper are listed in the following:First, the cross beam system is analyzed by finite element method. Based on the energyprinciple and the mechanical characteristics of the cross beam system, the stiffness matrix ofbeam element and equation of the whole cross beam system has been established.Second, the element free method for Winkler foundation has been introduced. Thismethod has less nodal parameter and computation workload. It can receive high precision,and simulate easily the non-regular plane raft.Third, the cross beam system and raft coupling model has been established. It issupposed that there are hinges between the cross beam and raft in the model. According toenergy principle, the coupling equation is established. The rotation angles of the beam endsare regarded the internal freedom of the cross beam system and condensed. The unknownquantities of the coupling equation are only deflections of the beams and the raft. Then thecomputer program for the ribbed raft foundation is developed.Fourth, the computation of example proves that this method is rational and has highreliability.In conclusion, the research indicates that this method is effective and reliable, and cancalculate deflections and internal forces for beams and rafts easily, especially for the irregularshape ribbed raft. Up to now, the report about the coupling method has not yet been found. So,the research has the important theoretic significance and practical value.