Study On Prestressing Impact To Internal Force Of Frame Structure

Prestressed concrete frame structure attracted more and more attention in the field of civil engineeringit for it to meet the requirements of large spaces, large span and good structural properties. In the past, researchers study focus on the effects of prestress to component itself, some scholars also study on the secondary internal force of column produce by prestressed beams by a simple structure, it is uncommon that study on the influence of complex structure and components under prestress. The paper take a plane of two layer frame structure of Lan zhou area as a case, use limited analysis software MIDAS, established non-prestressed framework structure and prestressed framework structure whole model.Firstly, study on effects of prestressed to structure overall performance, then analysis structure under static force, study on the effects of prestressed on structure deformation and forces under different loads condition, which to provides reference for similar structure design and construction. The contents of this paper includes the following aspects:(1)Based on the finite element analysis software MIDAS-GEN, simplify the structure reasonable, using beam element and plane element create aframework structure model;(2)Analysis the effect of prestressing to structural overall performance such as, structure mode、cycles、drift and the ratio of shear to dead weight. Results show that the effect of prestressing on stiffness、lateral stiffness and ratio of shear to dead weight of frame structure is small, but can causes the local stiffness change of structures;(3) Through static force analysis to whole frameworks, studied the effect of prestressing to the deformation and internal force of structure under different loads conditions. Results showed that under the action of prestressing, the deformation and internal force of majority components is decreased, but under different load conditions, the position of components maximum force will change;(4)In different load conditions, by comparative analysis the prestressed frame beams and non-prestressed frame beams deformation and internal force. Results showed that after prestressing, deformation of the beam are reduced, the internal force of majority beam is reduced; in some load conditions, prestressed can cause beam internal force increase;(5)In different load conditions, by comparative analysis the prestressed frame columns and non-prestressed frame columns deformation and internal force. Results showed that after prestressing, deformation and internal force of frame columns will decrease, but in some load conditions, prestressing stress can cause internal force of part of the column changes; prestressing force effect on the wear layer is particularly significant.