To improve the seismic capacity of prestressed concrete (PC) continuous girder bridges with corrugated steel webs (CSWs), suitable damping control measures can be used to effectively reduce the seismic response of the bridge. Based on the semi-active control theory, the semi-active control system of a three-span PC continuous girder bridge with CSWs is designed, and the semi-active control system program of the three-span PC continuous girder bridge with CSWs is compiled by MATLAB. The time–history curves of damper energy consumption of active optimal control algorithm and three different semi-active control algorithms are compared and analyzed, as are the time–history curves of main girder displacement, acceleration, and pier internal force with or without semi-active control. The study shows that the rational determination of the weight matrix coefficient can make the active control achieve a better vibration absorption effect and economy. The semi-active control algorithm of Hrovat has the best vibration absorption effect, which is closest to that of the active optimal control algorithm. Under the state of semi-active control, the average vibration absorption rate of displacement and acceleration of the main girder with CSWs are 71% and 20%, respectively. The time–history curve of bending moment and shear force in the pier bottom is similar, and the average vibration absorption rate of bending moment and shear force at the bottom of pier #2 is 70%. At the same time, the average vibration absorption rate of bending moment and shear force at the bottom of pier #3 is between 42% and 48%. The semi-active control measure has a good vibration absorption effect on the overall seismic response of the PC continuous girder bridges with CSWs. This study provides a certain reference for the seismic reduction and isolation design of composite structure bridge with CSWs.

Analytic Solutions of Shear Lag on Steel-Concrete Composite T－girder under Simple Bending

Steel-concrete composite beams are composed of concrete slabs and steel girders by shear connectors. Due to the limited rigidity of shear connector, and the shrink & creep property of concrete, relative slippage exists between the concrete slab and steel girder under bending, and it is difficult to analyze the effect of those factors by the ordinary beam theory, the finite element method(FEM) and so on. A differential equation of equilibrium is constituted corresponding to the compatibility of deformation and the equilibrium of forces of steel-concrete composite beams under particular assumed condition. Finite difference method (FDM) and variation principle are used to solve the differential equation. An example of steel-concrete composite T girder is given to analyze the effect of slippage and concrete shrink & creep on its stress and deflection. The concrete slab stress increases with increased rigidity in the shear connectors. The stress of the steel girder and the deflection of the composite girder decrease with increment in the rigidity of the shear connectors.

In order to study the ultimate flexural capacity of reinforced concrete beams with BFRP (Basalt fiber reinforced polymer), the test is designed and poured four T-section reinforced concrete beams. At first, monotonous static loading is carried on two of the beams until the chinks appeared. Afterward, all beams are strengthened by BFRP sheets. The contrast experiment studied and analyzed the different cracking load, ultimate load, deflection, reinforcement strain, concrete strain, fiber cloth strain, crack development of pre-reinforced beams and damaged beams strengthened by BFRP sheets. At the same time, the theoretical analysis and finite element simulation are performed to verify the result of experiment. The results show that the ultimate flexural capacity of reinforced concrete beams with BFRP has significantly increased. The circular bead treatment raises woke effect and reduces stress concentration of BFRP sheets.