| With the development of transportation in China in recent years,long-span prestressed concrete continuous rigid frame bridges have been widely used due to their advantages in economic cost,strong crossing ability,reasonable mechanism and convenient construction.Besides,the span ability of this type of bridge becomes longer because of the development of design theory,the emergence of high-strength materials and the improvement of construction technology.However,the data about many finished long-span prestressed concrete continuous rigid frame bridges suggest that big differences of mid-span deflections appear between design predictions and actual situations.And linear creep model in Chinese code cannot explain the phenomenon reasonably.Nonlinear creep of concrete is a phenomenon that the relationship between creep strain and stress shows a property of nonlinearity instead of linearity under particular circumstances.It may occur in concrete in actual bridges which are high stress and concrete damage.This article mainly carries out the following works:(1)Nonlinear creep models proposed by scholars are sorted out.The nonlinear creep model which is suitable for actual bridges are selected after comparison.(2)The selected nonlinear creep model is improved according to Chinese code and actual situations.User creep subroutines for both linear and nonlinear creep models are written using Ansys software.(3)The FEM Ansys models based on a long-term deflection test of reinforced concrete simply supported beams are set up to predict mid-span deflection using both linear and nonlinear creep models.Test values and calculated values are compared to verify the applicability of subroutines.(4)Long-term deflection prediction of long-span prestressed concrete continuous rigid frame bridges based on Humen auxiliary channel bridge is carried out.The FEM entity models are set up considering loss of prestressing,effect of live load,damage of concrete,creep and shrinkage.Both linear and nonlinear creep models are used in the article and the results are compared with measured values.Finally,some suggestions are proposed on the prediction of long-span prestressed concrete continuous rigid frame bridges considering nonlinear creep. |
