Analysis And Rresearch On The Influence Of Lateral Restraint To Post-tensioning Prestressed Concrete Structure

Prestressed concrete structure has overcome lot of shortcomings of reinforcement concrete,and it has been widely used in long-span and big room structures,and the structure that request strict crack resistance also need prestressed concrete structure.Modren prestressed concrete structure are mostly used in complicated hyperstatic structures.The vertical member of the structure—column and shear wall has lateral stiffness,it will restrict the compression deformation of horizontal member when the prestressed tendons being tensioned.So the vertical member will share a part of the prestress, this will produce the loss of the prestress of horizontal member.And it perhaps produce hidden danger.Therefore,a necessary analysis must be done on the influence level and influence law of the lateral restriction.On the summary of the research that has been done on the influence of the lateral restriction,this text firstly introduce the design methods that considering the lateral restriction influence of the prestressed concrete structure.Then the text deduce the calculation formula that calculate the lateral restriction influence coefficient,and then analyse the factors that effect the lateral restriction level.After that,the text introduce the generation mechanism and calculation of the secondary internal force in prestressed concrete hyperstatic structures.Ansys program has been widely used in numerical simulation of the engineering structures.The text introduce the analytical model in ansys program,and the element characteristics of concrete and steel,material model and constitutive relation,and the modeling method in ansys program of the prestressed concrete,and finally the simulation method of applying prestress is introduced.The influence level of the lateral restriction has something to do with the line stiffness ratio of beam and column,spans and the order of tensioning. In order to analyse the above factors of the lateral restriction,the modeling analysis in ansys program of different prestressed frame structure have been done in the text.In the text a conclusion which is about the change rule of influence level of the lateral restriction at different line stiffness ratios of beam and column,spans and the order of tensioning is presented.In addition the effect law of pillar to slab in prestressed slab--column structure has been analysed. Finally,the text put forward some designing suggestions and conformation measures that can reduce the the effect of the lateral restriction.In the end of the text,by measuring the effects which the lateral restriction produced in the living structures and the above analysis,an analysis of living prestressed structure has been done.And some questions when designing prestressed structure have been put forward,it could be reference for the engineering.