Influence On Main Arch Ring Of Bridge Abutment Horizontal Displacement And Arch Axis Deformation

Masonry and reinforced concrete are the most common material which are usually used in medium-and-small span length arch bridge in our country . After it was opened to traffic , the horizontal displacement of bridge abutment and deformation of arch axis often happen to upper loading arch bridges . In statically indeterminate arch bridge , the horizontal displacement of bridge abutment produces additional internal forces which make against the force bearing of main arch ring . The deformations of arch axis directly influence the distribution of the internal forces . So the influence of abutment horizontal displacement and arch axis deformations on the internal force of main arch ring are analyzed in this paper . The analysis is based on the previous obtained information and uses finite element analysis program for plan pole system to calculate .The research results demonstrate that when considering the variation of horizontal displacement with time the concrete creep decreases the additional internal force . When the horizontal displacement of arch foot completely accomplished , the reduced coefficient is . Among the vertical deformations of the main arch ring sections , the vertical deformation of three section of eight sections is the maximum value . The additional axial forces which are produced by horizontal displacement of arch foot in different sections are all tensile force . The horizontal displacement of arch foot produces negative moment in arch foot section controlled by negative moment and positive moment in crown of arch and three section of eighth which are controlled by positive moment . The additional internal forces make the each sections of main arch ring more disadvantageous . When the horizontal displacement is one in two thousand and five hundred of the computing span length , the arch foot section is dissatisfied the demands of sections bearing capacity though considering the change of bearing condition .Assuming some shapes of arch axis deflection , the calculation results demonstrate that deflections have little influence on vertical deformations of each sections in main arch ring . The change value of vertical deformations exceed no more than ten percent . The deflections have little effect on internal force and have a little more effect on forces produced by dead loads than live loads and temperature loads . So when calculating the medium-and-small span length arch bridge without the arch foot horizontal displacement , the internal forces by loads compute according to the designed arch axis . When arch bridges have arch foot horizontal displacement , the additional internal forces obtain from the horizontal displacement measured and else internal forces by dead loads and live loads still calculate under the designed arch axis .