The Analysis Of Reinforced Concrete Structure With The Abaqus User Subroutine MPC

The methods of analysis reinforced concrete structures have always been a hotissue, the core issue is how to deal with the adhesive of steel and concrete.The finite element software Abaqus has rich solution functionality and strong openarchitecture for the reinforced concrete structure, it’s Embedded method can simulatethe fully bonded relationship of steel and concrete, the various subroutine interfaceswere provided for users to achieve a variety of individual requirements. And multi-pointconstraint equations (MPC) technology can be used to simulate a variety of complexconnectivity relationships, it both can simulate the fully bonded relationship and thebond slip between the steel and concrete.This paper research on the Abaqus-MPC subroutine implementation technology tosimulate relationship between the steel and concrete. It includes the following:①It derived no-slip adhesive multi-point constraint relations of steel and concretenodes based on displacement coordination model. Then in accordance with the relevantrequirements of MPC subroutine, it prepared the MPC subroutine to deal with non-slipbonding. It compared the results between subroutine calculations and Abaqus ownnodes coupling methods and embedding methods. And the results were unanimous.②It obtained constraint relations of unbonded slip multi-point by lifting therelevant degrees of freedom constraints based on the no-slip adhesive. Then it preparedMPC subroutine to deal with unbonded slip in accordance with the requirements ofMPC subroutine, and verified its correctness through the method of equivalent loadsand deformation relationships. The method was more convenient than the currentprocess unbonded slip by adding a bonding element, it can easily be applied tounbonded prestressed structures.③It proposed approach of spring element and multi-point constraint for the caseof bond-slip. It created a new node in coincidence position of the steel node, thenestablished multi-point constraint between the new node and the concrete elements nodethat the new nodes and steel nodes bonding with spring element. This ratio was moreaccurate than directly established the spring connection between neighboring nodes, andit was more convenient than requires reinforcement and concrete node positionscoincide with the nodes when division unit.Through this research, it can be achieved bonded and unbonded analysis and calculation between the steel and concrete, and it can simulate the influence on thereinforced concrete structures with different bonding sizes of the steel and concrete:the deflection, the bottom edge of the principal tensile stress of concrete beam and thestress intensity factor of the crack tip is smaller when the bonding is effect.And thistrend is more obvious with the enlargement of the bonding failure area.