Based on Mises yielding condition theory,incremental theory and the assumption that the material is ideal elastoplastic,this paper obtained stress components of thin-walled straight bar with close section under tension,compression and torsion combined deformation by using non-dimensional method.

According to the theory of thin-walled bar with closed section,a combined mod-el is esta blished of coupling deformation,and an accurate method of analysing stresses between lay-ers is suggested.

Research on application of change from hyperbolic arch section into box section

By comparing the results of large scale model test with that of spatial finite-element analysis,the coefficients of shear lag about the box section of Luzhou Tai an Yangtze River Bridge under several typical loads are gained.

The hydraulic loads,which should be considered in design process,are discussed,including rising force,equivalent static hydraulic load,and dynamic rising force due to difference of water header between inner and outer of box section.