Advanced Materials Research Vols. 671-674

Abstract: The modal flexibility was more effective than structural frequency and displacement mode on damage detection of structures, it could be calculated easily based on low order mode of box girder. The damage detection method was proposed based on the modal flexibility curvature in this article, this indicator considered the impact of length difference of adjacent elements on modal flexibility matrix. Damage sensitivities of indicators is contrasted. Calculating results show that flexibility curvature difference has good detection effect on single point damage, multi-point damage and side element damage. The method in this article has good effect on damage detection of box girder.

Abstract: Dynamic test of double curved arch bridge based on environmental incentives. And Peak value method stochastic subspace identification method is used for modal analysis, and bridge modal parameters are obtained. The results were compared with the finite element software Midas civil, and results are consistent. The test shows that the bridge modal parameters can be identified in the environmental stimulus response. Measured frequency is lower than the finite element calculation of frequency; it means the bridge stiffness is lower. The identified dynamic properties can be served as the basis in the finite element model updating, damage detection, condition assessment and health monitoring of the bridge.

Abstract: The ultimate compressive strengths of high performance steel (HPS) plate system stiffened longitudinally by closed stiffeners have been investigated by the nonlinear finite element analysis. Both conventional and high performance steels were considered in models following multi-linear strain hardening constitutive relationships. Initial geometric imperfections and residual stresses were also incorporated in the analysis. Numerical results have been compared to compressive strengths from Eurocode 3 EN 1993-1-5 and FHWA-TS-80-205. It has been found that although use of Eurocode 3 EN 1993-1-5 and FHWA-TS-80-205 may lead to highly conservative design strengths when very large column slenderness parameters are encountered

Abstract: Many footbridges may suffer from the intensive vibration induced by human activities. To be a direct and effective approach, field measurement is widely utilized to assess the vibration serviceability of footbridge. The field measurement and modal identification of a cable-stayed footbridge is conducted in this study. The dynamic responses of the example footbridge subjected to ambient excitations are collected through field measurement and utilized to identify the structural dynamic properties by using two approaches. The made observation indicate that the peak acceleration responses at different testing points are different to great extent but the spectrum properties of all the points are quite similar. The fundamental frequency for the vertical vibration of the concerned footbridge is close to the lower frequency of the pedestrian loading and a relatively large vibration and discomfort of pedestrians can be observed

Abstract: Trough-to-deck plate joints in steel orthotropic deck are very sensitive to fatigue. A full-scale fatigue test of steel orthotropic deck was conducted to study the fatigue performance of trough-to-deck plate joints between two diaphragms. The test panel has three spans of 1.0m+3.5m+1.0m in the longitudinal direction and five troughs with the width of 3.0m in the transverse direction. At the end of the fatigue test, the cycles of the fatigue load reached to six million and no fatigue cracks were found by naked eye at the trough-to-deck plate joints. Based on the failure criteria of the measured stresses with a sudden change, it is confirmed that the fatigue strength of trough-to-deck plate welded joints with deck plate failure is similar to design category 71 in the Eurocode using the measured stresses at a distance of ten millimeters from the weld toe.

Abstract: Based on the shrinkage and creep theory model of the JTG D62-2004 and trough the finite element analysis software, it is to respectively calculate the main span displacement and the upper and lower edge stress of the steel beam and the concrete slab under the impacts of concrete shrinkage and creep at the initial stage and the normal operation stage (with 10 years of shrinkage and creep calculated) for the steel-concrete composite deck system of the cable-stayed with a main beam of 436m.The results show that the effects of the shrinkage and creep can’t be ignored.

Abstract: With the background of continuous rigid frame bridge,this paper considers the impact of the structural weight and the pre-stressed force in the construction phase,uses the ANSYS finite element analysis program to analyze the stress and strain of an continuous rigid frame bridge in the the largest cantilever state, focuses on different effects of the different radius of curvature and pier height.Through the analysis constructs the control mentality and the corresponding design proposal for the continuous rigid frame bridge had been provided.

Abstract: The modeling techniques selected for girder bridges should be capable of including physical behavior, such as composite action and the eccentricity effect between the slab deck and the girder. In this paper, we find that the ANSYS has the capability of offsetting the beam element from a reference node location in order to define the centric location of the section relative to the node location.

Abstract: It exists a great influence on deformation and internal force of large span bridge when temperature changes, the influence of the temperature must be considered and try to avoid in the process of construction control. Under monitoring to the construction process of Tieluoping super-large bridge on the scene, the influence law on internal force of Tieluoping Bridge is analyzed considering temperature effect, and the influence considering the sunshine temperature difference on cable tower deviation and stress is obtained, and the size of influence of main girder elevation, cable force and strain because of temperature field and distribution rule internal temperature field are clear. It provides powerful help for the smooth construction.

Abstract: The Usu Bridge is single cable plane single tower cable-stayed bridge, the finite element program is used in this paper, the tensile、compression damage model of Concrete Materials is adopted, the damage of concrete structures of Usu main bridge under the combination of four kinds of static load is calculated, we get the damage distribution of the main tower and the main beam、the location of maximum damage and the effect of loading conditions, from which we find that the change of temperature has a greater impact on their damage and the role of the extreme wind has a greater impact on the main tower, thus we propose reasonable proposals on the construction and maintenance of the bridge.