Slab bridge is constructed frequently as a short-spanned bridge. Usually the design and analysis of slab bridges are based on the beam theory. But, for more exact analysis/design plate structure analysis with finite plate elements should be performed rather than beam analysis. However, modeling and result analysis of plate structure with finite plate elements are so complicated that much time and cost are spent. In addition the analysis for live loads like truck loads and lane loads requires envelope surfaces of plate structure using 2-dimensional influence surfaces, therefore it includes enormous calculation procedures and if there are lots of analysis points for design it may be impossible to compose envelope surfaces.
This paper aims at the development of the algorithm which can automatize such complicated envelope surfaces calculation of slab bridges modeled as plate structures. Finally finite element analysis program for slab bridges including algorithms which can automatize the calculation of envelope surfaces for live loads has been developed.
Convergence tests and shear locking tests are performed to check the developed finite element program.
"Chukkye Bridge" is modeled to check the developed output algorithms of envelope surfaces for live loads. And the analysis results are compared with those of SAP which is a general FEM program used nowadays widely. And the two results show good agreements.
The developed program is based on the graphic user interface environment under Window 97. So the program gives much efficiency in such works as loads input, finite element modeling and output analyses.
