Advanced Materials Research Vols. 255-260

Abstract: In the design of continuous rigid frame bridge setting reasonable pre-camber can eliminate the impact of various loads on the linear in construction process, reduce shrinkage and creep in the process of post-operation, the late loss of pre-stressed, deformation produced by live load and so on ,resulting in deflection phenomenon. Based on the current specifications of the continuous rigid frame bridge camber setting methods, this thesis proposes the reasonable setting suggestions of pre-camber and sets examples to illustrate this.

Abstract: Damping in double chains suspension bridge is non-uniform, which leads to coupled motion equations in main coordinate system. Based on the complex damping theory to solve equivalent viscous damping ratio used to describe energy dissipation characteristics of non-classical damping system approximately, a method is proposed to analyze seismic response of double chains suspension bridge considering non-classical damping modified by measured value. Influence of different damping forms on seismic response of double chains suspension bridge is analyzed, considering classical damping and non-classical damping respectively, through an example of double chains suspension bridge. The analysis shows that non-classical damping has significant effect on seismic response, and response based on the classical damping model is not reliable to double chains suspension bridge. Non-classical damping model should be used in seismic analysis of double chains suspension bridge, however, the seismic response of non-classical damping system under the longitudinal or vertical seismic wave can be substituted approximately by the seismic response calculated according to damping ratio of concrete tower and steel stiffening girder respectively, which can simplify the calculation during preliminary analysis.

Abstract: In this paper ,the axes of a three-span dumbbell-shaped steel tube concrete arch bridge was changed due to deviation in bridge piers, tie beam construction and steel tube production, thereby steel tube arch ring can not be closed, and suspender hole can not be aligned. The side-span hollow steel tubes were intercepted and adjusted for three times through calculation and analysis, therefore the structure stress is reasonable and achieved original design standards under the condition of not changing the original arch axes, and the bridge was successfully constructed, thereby providing reference for engineering staff.

Abstract: Due to the applicable installation height, small mass, flexible characteristic, large span, and small damp, the unit glass curtain wall (UGCW) could easily result in vibration with the wind effect. The main factor is the turbulence among the cause effects. Combining the structural dynamic theory, and considering the characteristic of the UGCW, a wind effect calculation formula is set up considering the turbulent wind that is resulted by the 1st vibration type. Hope to provide some reference for similar designs.

Abstract: Floating or semi-floating systems are usually employed for long-span cable-stayed bridges to lengthen their fundamental periods, and accordingly, to reduce their seismic inertial force, but the structures’ seismic displacements could be increased by utilizing these systems. Taking Yong-jiang railway cable-stayed bridge which has a low center of gravity as engineering background, the function of viscous dampers in controlling seismic displacements is studied. Firstly, the rational parameters of dampers are determined by parametric analysis, and then the seismic displacements and forces of the bridge, utilizing and un-utilizing viscous dampers, are compared. The results show that: viscous dampers are efficient in controlling seismic displacements of the bridge; the seismic shear forces at the bottom of towers are reduced slightly and the corresponding moments are reduced in a larger extent for cable-stayed bridge with low center of gravity.

Abstract: Cracks appeared in concrete structure is always concerned in construction engineering. As the cracks appear, the rigidity of structure will descend. So only the combination of slip theory and the non-slip theory could reflect the development of cracks in the course of analysis of cracks development. For axial tension and bending components, stiffness changes before and after cracking. The continuous beam with equal span is analyzed under the temperature load by the finite element method. As the cracks with different space appear, there is an abrupt bending moment with every crack. Different crack spacing, crack steep drop differently. So the wider the crack’s space is, the higher the abrupt bending moment is.

Abstract: Parameter changes of a bridge in construction process must have an effect on its stress and alignment.And different parameters ,in the same bridge ,affect state of bridge to a different degree. While we have no need to consider every parameter in practical construction process, just paying attention to some sensitive parameters with a great effect on bridge structure instead .So a reseach of parameter sensibility of bridge construction is necessary to find out sensitive ones of all to limit their great effect .In this paper, based on JinZhou cable-stayed bridge without backstays,we use Midas civil to analyze the degree of impact of each parameter on stress and alignment of main girde ,which is depended on to put forward the main sensitive parameters of the bridge in construction process and a few of advice about its construction technology.

Abstract: Rotation construction method includes building the bridge parallel to the obstacle being spanned (a river, a highway or a railway) and then rotating the superstructure into place. The method can optimize bridge construction in terms of reducing impacts on traffic, safety, and overall project budget and duration. Therefore, the method became so popular that it has been used successfully in about one-hundred bridges in China. In this paper , taking the Suifenhe cable-stayed Bridge as project background, the design idea (single point with flat hinge) of bearing system has been brought forward. The successful rotation construction of Suifenhe cable-stayed Bridge proved the feasibility and technical advancement of the horizontal rotation construction method with flat hinge in similar engineering construction, especially the bridges with symmetry structure.

Abstract: In order to model the elasto-plastic behavior of steel-concrete beams in high-rise buildings correctly and conveniently, plastic hinge method is used. Based on experimental and theoretical research on composite beams, the trilinear moment-curvature skeleton curve of steel-concrete composite beams is amended by numerical simulation and theoretical analysis. And the 4 poly-line moment-curvature skeleton curve model is suggested for elasto-plastic analysis of steel-concrete composite beams. The elastic-plastic model is then used for real composite beams under monotonic load experimental analysis to verify its precision. The suggested model can lay a foundation for the dynamic analysis under strong earthquake for the globe steel-concrete composite structures.

Abstract: Some retrofitted methods are introduced, and in these retrofitted methods, a strengthening case of using the sandwich plate system (SPS) to strengthen the orthotropic steel bridge deck of a suspend bridge was studied. A local finite element model is established by ANSYS based on an orthotropic steel bridge deck sample, stress distribution of deck due to the wheel load of the vehicle defined in China current code were analyzed under different loading conditions, and the strengthening effect with SPS was evaluated. The influence of the thickness and elastic modulus of elastic sandwich on the transverse stress of deck was analyzed. The results show that, compared with the orthotropic steel bridge deck before strengthened, the stress peak is decreased obviously without new welding residual stress be generated, and the fatigue resistant of bridge deck is increased apparently after the deck strengthened by SPS. The variation of the thickness and elastic modulus of the elastic sandwich have little influence on the stress behaviours of the orthotropic steel bridge deck.