Abstract: In order to study the stress behavior and diaphragm effect of steel-concrete curved composite beam, model test and finite element analysis were conducted on six simple model beams stiffened with diaphragms. The span-radius ratio and the number of diaphragms were taken as the design parameters. Under the concentrated load at the middle span of the beam, the whole process behavior, section strain and interfacial slip were analyzed. The results show that, with the increase in span-radius ratio the bending-torsional failure of the steel-concrete curved composite beam becomes more obvious; while the number of diaphragms has little influence on the bending-torsional failure. At positions close to the diaphragm the tangential and radial strains are small inside the curve and large outside the curve, which are reverse at position far from the diaphragm. The tangential and radial slippages between the concrete slab and steel girder both increase with the span-radius ratio; while the number of diaphragms has little influence on the tangential slippage, but the radius slippage increases close to the diaphragm. The diaphragms have large effect on the transverse distribution of the strain, and the end diaphragms can enlarge the torsional stiffness of curved composite beams apparently.

Key words: civil engineering structure, steel-concrete curved composite beam, bending-torsion couple effect, diaphragm, model test, finite element analysis