Semicontinuum analysis of shear-weak grillages

Abstract

Cellular bridges and voided slab bridges with large and frequently spaced circular voids undergo distortion of the cross section under nonuniform loads, which may have a significant effect on the load distribution characteristics of the bridge. For two-dimensional analysis of these bridges, it is usual to represent the transverse medium of the bridge as having finite shear rigidity. Up to the present time, the semicontinuum method of analysis did not have the capability of handling finite shear rigidity of the transverse medium. A modification is introduced in this paper through which it can now do so. It is shown that the proposed modifications consist of only minor changes to the set of equations of the earlier version of the method. By comparing the results of the proposed method with those obtained from grillage analysis, it is shown that the accuracy of the proposed method is equal to that of the grillage method, which has already been found by many researchers to be suitable for the analysis of shear-weak bridges. The paper also contains proposed modifications to the semicontinuum method so that it can handle finite shear rigidities of the longitudinal beams as well. Key words: analysis, bridges, load distribution, semicontinuum method, shear rigidity, shear-weak grillages, shear-weak plotes.