RESEARCH ON LOAD-CARRYING CAPACITY OF CONCRETE FILLED STEEL TUBULAR DUMBBELL SHAPED RIB ARCH UNDER IN-PLANE LOADS

Experiments on concrete filled steel tubular (CFST) dumbbell shaped rib model arches have been carried out with loads concentrated at crown and L/4 sections respectively. The result indicates that CFST dumbbell shaped rib arch has good elastic-plastic behavior and high strength, and no local buckling during the whole loading process. Its in-plane mechanic behavior is similar to that of the CFST arch with single tube. A dual nonlinear finite element model is developed and the calculation results agree well with the experiment results. A comparison of the load-carrying capacity of arches is carried out between the finite element method and the equivalent beam-column method. The parameters considered are the ratio of rise to span, slenderness ratio, steel ratio and loading patterns. It is found that the variation of load-carrying capacity of CFST dumbbell shaped rib arch are similar to those of the single tube rib arch. It is also found the calculated curves by the equivalent beam-column method and that by the finite element method have the same pattern.