Mechanical Performance Analysis Of Cable-stayed-suspension Hybrid Bridge

The cable-stayed-suspension hybrid bridge is a new bridge type ofcable-supported bridges, which is developed from suspension bridge andcable-stayed bridge. It takes the main advantages of the suspension bridgeand cable-stayed bridge, and also makes up the deficiencies existing in thesuspension bridge or cable-stayed bridge such as the mechanicalperformance, construction and wind stability. The cable-stayed-suspensionhybrid bridge provides a comparatively ideal bridge type for thestrait-crossing projects in the 21st century, due to its elegant shape,reasonable load carrying, strong crossing, good wind resistance, safeconstruction, low cost and so on, especially suitable for the locations facedwith bad natural conditions such as the deep-watered foundation and theviolent typhoon. This paper gives a systematic study and discussion on thestatic performance, dynamical characteristics and wind resistance of thecable-stayed-suspension hybrid bridge. The results can provide helpfulguide and valuable reference for the design of the cable-stayed-suspensionhybrid bridge.The computer programs including GNFEA based on CR formulationfor structural three-dimensional geometrical nonlinear finite elementanalysis, SDCA based on the sub space iteration method for structuraldynamic characteristic analysis, BSNAA for bridge structure nonlinear aerostatic analysis, and BSLFA for bridge structure linear flutter analysis,on one hand, are used to investigate the mechanical performance of thesuspension bridge, cable-stayed bridge and cable-stayed-suspensionhybrid bridge with a main span of 1400m including the static performance,dynamic behavior, and the aerostatic and aerodynamic stability, and thepossibility of applying the cable-stayed-suspension hybrid bridge inlong-span bridge is also discussed; on the other hand, are used toinvestigate the effect of design parameters such as the sag to span andsuspension to span ratios, the side span, the cable plane layout and thearrangements of the auxiliary piers in the side spans etc. on the mechanicalperformance of cable-stayed-suspension hybrid bridge. The key designparameters are pointed out and their reasonable values are also discussed.The results show that: (1) the cable-stayed-suspension hybrid bridgehas greater structural stiffness, less deformation and internal force underthe live load, and better structural stability under the wind action, andtherefore is an ideal structural system for long-span and super long-spanbridges. (2) The mechanical performance of cable-stayed-suspensionhybrid bridge is the best, when the sag to span ratio is about 0.1 and thesuspension to span ratio reaches the range of 0.4～0.5, and short side-span,outward inclined stay cable plane and the auxiliary piers in the side spansare used.