Applied Mechanics and Materials Vols. 438-439

Abstract: Diaphragm distributes lateral loads, and improves mechanical properties of bridge structure of prestressed concrete (PC) continuous wide girder bridge. The role of diaphragm is more prominent in composite wide girder bridge with corrugated steel webs, which stiffness is smaller compared with PC continuous bridge. Diaphragm is calculated and analyzed of composite box-girder bridge with corrugated steel webs, and reinforcement schemes are presented, aimed at diaphragm crack width overrun and insufficient bearing capacity. The reinforcement scheme is adding prestressed steel cables and special supports, stress and crack resistance are analyzed on reinforced diaphragm to verify the existing problems can be completely solved.

Abstract: Corrugated steel webs have crinkled effect without capacity bearing the axial force and bending moment, which leads to its effective elastic modulus is smaller than that of material. This paper deduced the computational formula of effective elastic modulus corrugated steel webs, and puts forward the calculation method for corrugated steel webs of composite beams. Combined with a continuous composite box-girder bridge with corrugated steel webs, the finite element model is built to analyze the bending performance such as normal tensile stress, normal compressive stress and crack resistance.

Abstract: By using the finite element analysis software ANSYS to do the first 10 order modal analysis of suspension bridge, obtaining the natural frequency and natural vibration model, to avoid the structure has resonance phenomenon. The results show that inherent frequencies of the first 10 order of the suspension bridge are far less than the excitation frequency of vehicle, the speed of mobile has obvious influence on the mid-span nodes deflection, when the vehicle goes through the suspension bridge, it usually travels at low speed; vehicles traveling at the same direction have a greater impact on the suspension bridge structure, the maximum mid-span node deflection of the suspension bridge decreases with the increasing of angular frequency.

Abstract: Floating system of cable-stayed bridges under seismic action will produce larger longitudinal bending moment and displacement, in order to ensure the safety of the structure, damping measures should be taken in longitudinal direction. Taking a mainspan for 416 m of the cable-stayed bridge as an example, four different damper layout schemes were analyzed by nonlinear dynamic time history method. The results show that installing viscous dampers at the abutment location to function better comparing with other three cases. For getting the best damping effect, the optimal parameters of damper are analyzed. The investigation indicates that adding viscous dampers can significantly reduce the girder movements, and the reduction depends on damper parameters. Finally, the optimal damping parameters with ξ=0.3 and C=10000 can be chosen for this cable-stayed bridge.

Abstract: To ensure the construction quality, safety and reliability, according the design drawings, construction process and the related design code, this paper establishes the simulation model by the software of MIDAS/CIVIL for the analysis of construction control of the low tower cable-stayed bridge. The calculation results showed that the maximum cumulative horizontal displacement of the tower and vertical displacement of the beam is 13.8mm and 154mm respectively, which can be adjusted by setting camber. At completion state of the cable-stayed bridge, the stresses of the tower and the beam are both in compressive with the maximum of 14.47MPa and 14.03MPa respectively, which are both less than the limits of corresponding materials. The bridge is safe and reliable.

Abstract: In the process of modeling, ignoring the displacement of the pier directly replaced with fixed constraint, beam elements were adopted to simulate girder and pylon, and link elements were adopted to simulate the cable. The first ten order natural vibration mode and natural frequency were obtained, and the dynamic characteristics analysis of a single pylon cable-stayed bridge was discussed, which can provide certain reference and guidance for solving the problem of the cable-stayed bridge design.

Abstract: Grillage method was an effective method for analyzing bridge structures. In order to validate the grillage method met the requirements of engineering precision in calculation about box girder bridges, the grillage model and the plate element model of the bridge were built by using the finite element software Midas/Civil; under the premise of the same loading location and the load value, the deflection values and the stress values calculated from the two models were compared, and the corresponding error ranges were obtained. The results show that the differences between them meet the engineering accuracy and using the grillage method in box girder bridges is reasonable.

Abstract: By the detection of a three spans continuous beam bridge, the detection loading method and arrangement of measuring points are discussed, the static and dynamic detection results such as the deflection, stress and inherent vibration frequency are comparative analyzed with those of theoretical calculation. Results show that the bridge is safe under actual working condition, which provides the basis for normal operation and maintenance of the bridge.

Abstract: With the length of stay cables close to 580m, only inclusion in aerodynamic forces of main deck cannot reflect the actual situation during wind-resistant design. The aerodynamic forces of stay cables should be considered in the three-dimensional flutter analysis of cable-stayed bridges. In this paper, mathematic expressions of unsteady aerodynamic force of stay cable were then derived in terms of aerodynamic damping and stiffness matrices. The above procedure is implemented into NACS by an independent module. As an example, the multimode flutter analysis of Sutong Bridge was conducted by using NACS. Fair agreement is achieved between the present numerical simulation and wind tunnel test results.

Abstract: A 10DOF composite beam element was developed, which had taken the interface slip effect and geometric nonlinearity into consideration. The method to obtain structural response gradients of composite beam was analyzed, meanwhile the reliability index was achieved by using the FORM method and on this basis, and the sensitivity of random variable parameters could be finished. At last the control of target elevation was took as state performance function, the sensitivity analysis of random variable parameters which might have an effect on the elevation control reliability was effectively completed, and some useful conclusions which were be beneficial to construction control of composite beam cable-stayed bridge obtained.