Performance Research On Long-span Continuous Rigid Frame Bridge With Hybrid Girders Of RPC And Normal Concrete

All the three largest span continuous rigid frame bridges reduce thier dead weight by adopting high-strength and lightweight material, such as steel and lightweight concrete. On the basis of this idea, the application of Reactive Powder Concrete(RPC), instead of steel and lightweight concrete, in large span continuous rigid frame bridge could not only lead to the decrease of dead weight of the structure and the increase of the span, but also avoid the complicated steel-concrete joint and the defect of lightweight concrete. Moreover, the durability of the structure would be enhanced. This dissertation proposed a RPC-normal concrete hybrid girder bridge with a long main span and a quite low side-to-main span ratio. At the same time, another scheme with the same span arrangement but the superstructure is built of normal concrete was designed for comparison. By means of initial scheme design, local analysis, static performance analysis and seismic performance analysis, the feasibility of the schemes was discussed and advantages and disadvantages of them were compared. The main work of this thesis is as follows:(1)Based on the engineering background, an RPC-normal concrete hybrid girder bridge with a main span of 330 m and a side-to-main span ratio of 0.31 was designed, including the design of the material parameters, the detail size of the structure, the distribution of prestressing tendons and the construction scheme. Besides, a scheme with the same span arrangement but the superstructure is built of C60 concrete was designed for comparison.(2)The local performance of the RPC box girder was checked. The results show that the buckling failure of the slabs of RPC would not take place before material failure. The punching resistance of the deck slab has a large surplus and the bending resistance of it could also met the requirements.(3)The structural static performance of the RPC+C60 concrete bridge and the C60 concrete bridge was studied. And the structural stability of them was analyzed. The results show that both schemes could meet the stand ard requirements and have reasonable stress and good feasibility.(4)The advantages and disadvantages between the two schemes were compared and analyzed in structure effectiveness and economical efficiency. The results show that the deadweight of the superstructure of the RPC+C60 concrete hybrid girder bridge is reduced by about 28 percent. Consequently, the structure effectiveness is significantly improved, and the live load effect ratio is 1.6 times as large as C60 concrete girder bridge. Because the consumption of RPC is controlled and other materials consumption is cut down, the RPC+C60 concrete hybrid girder bridge shows an obvious advantages in economy, of which the cost is 17.3 percent lower than C60 concrete girder bridge.(5)The seismic performance of the sturctrues was analysed based on response spectrum method and time history analysis method respectively, then the pros and cons of the two schemes and the feasibility of them were discussed. The results show that the RPC+C60 concrete hybrid girder bridge has smaller earthquake response than C60 concrete bridge, and its seismic performance meets the requirements, which further demonstrates the feasibility of RPC+C60 concrete hybrid girder bridge.