Mechanical Performance Analysis Of Extradosed Cable-stayed Bridge With Corrugated Steel Webs And Single Central Cable-plane

In the recent two decades,the extradosed cable-stayed bridge(E-D bridge)with corrugated steel webs has appeared and been gradually applied in practical engineering and achieved good engineering results due to its light weight,no cracking of webs,high prestress efficiency and easy construction.The E-D bridge with single-box and multi-cell wide cross-section girder has obvious spatial effect.In the whole and local calculation of this kind of structure,the existing simplified calculation method can not meet the design and construction needs.Based on the engineering background of an E-D bridge with central single cable-plane and corrugated steel webs,the whole structure and local structure of the E-D bridge with single-box multi-cell corrugated steel webs are studied by using the finite element method,and the influencing factors of the steel anchor box in the cable-girder anchorage zone are studied..The main contents and conclusions are as follows:(1)Based on Castigliano theorem,the web longitudinal stiffness reduction factor in spatial grid model of composite beams with corrugated steel webs is derived.The accuracy and applicability of the spatial grid model in the single-box multi-cell composite beam with corrugated steel webs are verified by the analysis of an example.The spatial grid model of the bridge in engineering background is established and static calculation is carried out,which shows that the spatial grid model can better simulate the stiffness and spatial effect of the main beam.The spatial grid model should be used in the calculation of single-box multi-cell composite beam with corrugated steel webs.(2)Based on the existing spatial grid model,the solid finite element model of the bridge segment and the finite element model of the whole bridge are established by using the hybrid element method,stress analysis of the cable-girder anchorage segment and the steel anchor box area is carried out.The results show that the shear distribution and stress distribution of the web are affected by the cable anchorage structure of the central cable-plane,the shear plate and steel guide beam are the important components in the cable force transmission path.(3)Based on the existing research,the sub model of steel anchor box area is established with the parameters of cable inclination,shear plate spacing and key plate thickness,and then the parameter analysis is carried out.The results show that the stress at the junction of shear plate and steel guide beam can be improved by increasing the angle of stay cable.Increasing the spacing of shear plates will improve the stress of web and perforated plate,but it will aggravate the uneven stress of inner and outer web.Increasing the thickness of the key plate can reduce the stress level of the related plate,and the improvement effect of the stress at the junction of the steel guide beam and the shear plate decreases with the increase of the thickness of the steel guide beam.