RIGIDITIES OF HORIZONTALLY CURVED FLAT STRUCTURES

Horizontally curved, wide flat structures are quite often used as supe rstructures of bridges and as floor slabs in large exhibition halls. S uch structures are built in reinforced or prestressed concrete constru ction, or in composite construction with a concrete-slab-on-rigid-stee l gridwork. To predict accurately the response of such curved structur es to static and dynamic loads, it is essential to use accurate estima tes of the structure's various rigidities. In this paper. analytical e xpressions are derived for predicting the flexural and torsional rigid ities during the precracking and postcracking stages. The experimental program consisted of nine tests on one-eighth-scale, horizontally cur ved, concrete waffle slabs. There were three series of tests, each con sisting of three types of specimens-two rectangular in plan for the pu re bending tests and the third square in plan for the pure twisting te st. Results from the experimental investigation confirm the analytical predictions for the various rigidities during the precracking and pos tcracking stages, It is also shown that the torsional stiffnesses of h orizontally curved, flat structures are much higher than previously es timated.