Analysis for the influence of structural parameters on static characteristics of CFST double X-shape arch bridge

In order to study the static characteristics and the stability features of concrete-filled steel tubular(CFST)double X-shape arch bridges,a 100 m span bridge to be constructed is analyzed.The influence of the key structural parameters(the ratio of rise to span,the distance between the suspenders,the rake angle of inclined arch,the number and location of transverse braces) on the internal force of the entire bridge is analyzed.The results show that: when the ratio of rise to span changes from 1/5 to 1/6,the internal force will increase largely;the increase of the distance between the suspenders and the decrease of the number of the transverse braces will increase the internal force of the inclined arch;the decreased skew angle of the inclined arch will increase the internal force of the main arch,tie beam and inclined arch;the springer transverse brace is the most important factor for the improvement of stability of the structure.The stability analysis results show that the instability modes of the bridge are out-of-plane.The stability coefficient is proportional to the rise/span ratio and the skew angle of the inclined arch.The distance between the suspenders has large influence on the dead load and stability of the bridge.The results also recommend some structural parameters for the design of bridges of this sort.