Mechanical Performance Analysis And Experimental Research On Concrete Self-anchored Suspension Bridge

With no large anchor and its lower cost, self-anchored suspension bridge(SASB) is now catching more attention by its elegant shape. It has become a competitive design scheme in middle-, and small-span bridges in cities. Based on the documents at home and abroad, the static force performance and dynamic behavior of concrete self-anchored suspension bridge(CSASB) are systematically investigated in this paper. At last, theoretical calculation is proved by model experiment of a CSASB being constructed. The main conclusion covers the following aspects:(1) Based on Wanxin Bridge in Fushun city, the static force performance of CSASB is analyzed. The difference between SASB and earth-anchored suspension bridge(EASB) is revealed.in this paper. Bending moment and deflection at the span midpoint of SASB are greater than those of EASB. The reason is that the great axial pressure in the main beam of SASB decreases its stiffness. The result calculated with elastic theory is similar to the result calculated with finite element model. Elastic theory is applicable to middle-, and small-span SASB. The infection by shrink and creep of concrete is obvious. Bending moment and deflection at the span midpoint are inversely proportional to rise-span ratio, camber and inertia moment of main girder. Enhancing the inertia moment of main girder will decrease the deflection at the span midpoint; however, it will increase the bending moment of the span midpoint at the same time.(2) Based on Finite Element Method, the dynamic computation model of Wanxin Bridge is set up. The first 20 frequencies and corresponding vibration modes of Wanxin Bridge are given. According to the result, the natural period of vibration of this bridge is long. This proves the suppleness of suspension bridge. The natural period of vibration of SASB is longer than that of EASB with the same span and structure parameters. This indicates that the stiffness of SASB is less than that of EASB with the same span and structure parameters. The seismic r esponse o f Wanxin B ridge i s a nalyzed w ith t he R esponse S pectrum M ethod. T he result indicates that vertical vibration has a strong influence on the bridge.(3) Based on Wanxin Bridge, an experiment model with a scale of 1:40 was made in bridge laboratory of Institute of Bridge Engineering, Dalian University of Technology. Static test and dynamic test were carried out on the model. The result of experiment coincides well with that of theoretical computation. Thereby the simulations and presuppositions are correct in theoretical calculation. At the same time, the result of experiment also indicates that the mechanic performance of CSASB in middle-, and small-span presents linear elasticity in finished state, and linear elastic theory is applicable to CSASB. The research in this paper is useful to direct design and construction of such kind of bridges.