钢管混凝土提篮拱面外受力性能试验

为探究非保向力效应对钢管混凝土提篮拱桥平面外稳定性能的影响,开展了钢管混凝土(CFST)提篮拱空间受力性能试验和有限元分析;基于某原型桥开展了考虑吊杆影响的钢管混凝土提篮拱空间受力性能试验,揭示了模型拱的破坏机理;基于试验结果和实际工程构造参数建立了钢管混凝土标准提篮拱桥有限元模型,通过是否建立杆系吊杆的方式分别考虑吊...

Experiment on out-of-plan mechanical behavior of CFST X-type arches

To investigate the effects of non-conservative forces on the out-of-plane stability of concrete filled steel tubular (CFST) X-type arches, the structural spatial mechanical behaviors of CFST X-type arches were analyzed via experiment and finite element analysis. Based on a prototype bridge, the structural spatial mechanical behaviors of a CFST X-type arch with hangers were tested to elucidate the failure mechanisms of the arch model. A finite element model of a standard CFST X-type arche was created based on the experimental data and the actual structural engineering parameters. The conservative and non-conservative forces from hangers were considered respectively in models with or without tie hangers. The effects of arch rib inclination, rise-span ratio, and width-span ratio on the out-of-plane ultimate bearing capacities of CFST X-type arches considering the non-conservative force from hangers or not were analyzed. Based on a finite element model for combined material and geometric nonlinearities and in terms of load and displacement ratios, the improvement in the spatial mechanical behaviors of arch rib due to the non-conservative force was quantitatively analyzed under different parameters. Research results indicate that during the spatial mechanical process, the displacement of the CFST X-type arch is symmetrically distributed about the crown section, and the strain distribution is also highly symmetric. Therefore, the arch model has good overall stability and low sensitivity to initial geometric defects during the spatial mechanical process. The arch model ultimately failed due to an out-of-plane extreme point instability. The arch rib mainly bears compression and out-of-plane bending moment, and the out-of-plane bending moment is the main controlling factor for the stability and ultimate bearing capacity of the arch model. The out-of-plane ultimate bearing capacity of CFST X-type arches initially increases and then decreases with the increasing arch rib inclination, rise-span ratio, and width-span ratio. The arch model reaches its maximum ultimate bearing capacity when the arch rib inclination is 9°, the rise-span ratio is 0.25, and the width-span ratio is 0.03. The non-conservative force should be considered when calculating the out-of-plane ultimate bearing capacity of CFST X-type arches, as the omission of the force will lead to a 22% underestimation of the out-of-plane ultimate bearing capacity. 1 tab, 21 figs, 32 refs.