Advanced Materials Research Vols. 243-249

Abstract: Under the action of both dead and live loads, the welding joints of the integral bridge deck and the main truss gusset plates of a steel truss bridge in the transverse and longitudinal directions are all subjected to tensile force, the fatigue performance of which greatly influence the safety and durability of the bridge during operation. Fatigue tests were carried out on a full-scale model designed and made in accordance with the structural details of the welding joints of the integral bridge deck and the main truss gusset plates of Dashengguan Changjiang River Bridge. On the basis of the results of the fatigue tests, the stress distribution of the welding joints was analyzed, the fatigue life of the welding joints under load cycles with constant amplitude was discussed and the fatigue performance of the welding joints under the condition of two-way tensile forces was studied. It is concluded that under the effect of fatigue loading with given amplitude, the fatigue life of the welding joints is more than 200 million numbers of load cycles, the structural details of welding joints have ample fatigue resistant ability under the condition of two-way tensile forces, and the maximum main stress value of the fatigue tests is lower than the allowable fatigue stress value given in various codes and relevant references and the fatigue strength meets requirement.

Abstract: In this paper, the vehicle-bridge lateral vibration mechanism was analyzed; the vehicle-bridge vibration model was built and the lateral reinforcement schemes of open steel plate bridges were designed. Numbers of analysis were carried out for the lateral vibration of 40m deck steel plate bridges before and after reinforcement, under input of random artificial hunting waves and track irregularity. The results showed that, the frequency of hunting motion is approaching loaded frequency of the girder. The larger lateral amplitude appears on the bridge when the hunting wavelength is around 8~9m and the velocity of the train is around 55~70km/h. The wavelength is longer, the resonant velocity of the bridge is higher.

Abstract: The temperature distribution and strains due to heat of hydration of cement in a concrete box girder were measured on site during construction of the Harbin Songpu Bridge. The lateral and vertical temperature distributions and stresses in webs and slabs were analyzed. The study of the measured results shows that there are large temperature differences in the box-girder sections, and both the lateral and vertical temperature distributions and stresses are nonlinear. In some parts of the sections, the tensile stresses are even greater than the characteristic value of concrete tensile strength.

Abstract: The commercially available finite element program ANSYS was used to model the refrozen process of the bored pile. The effects of the refrozen process by casting temperature of concrete, heat of concrete hydration and air convention were analyzed. To estimate the time when the bearing capacity of the bored pile is formed, the finish time of refrozen process was determined by modeling the whole refrozen process of the bored pile. The calculated results are in good agreement with experimental data. The analysis shows that the refrozen process is related with the casting temperature of concrete. The higher the casting temperature is, the more time the refrozen process takes.

Abstract: Orthotropic decks are commonly used in high-speed railway bridges. Finite-element model is established by ANSYS for orthotropic steel bridge deck in this paper. Taking the standard PDL ZK live load as the train load, the local stress of the rib-to-deck joint, the rib-to-crossbeam joint, and the cut-outs of the crossbeam are analyzed respectively. Analysis results show that the stress concentration of bridge deck mainly appears at the intersecting part of the U-shaped rib, crossbeam, and bridge deck. In the whole bridge deck, the local stress level of the cut-outs in crossbeam is almost the highest, and the cut-outs is distorted seriously; the maximum stress of crossbeam cut-outs is mainly concentrated at the lower arc of the cut-outs, which is one of the positions prone to fatigue failure.

Abstract: The mechanical characteristics and common forms of beam-arch combination system bridge and its new development are introduced. With the rapid development of economy, more and more steel structures are applied to bridge engineering. The usage of steel structure makes the pursuit of aesthetic possible besides the requirements of safety, economy and practicality. Furthermore, the aesthetic design is playing an important role in bridge design, especially in the design of an urban bridge. Aesthetic of a bridge is part of the aesthetic of environment, but which far surpasses the limited rang of environment where it is constructed. The beam-arch combination system bridge has achieved considerable development because of the requirement of aesthetic, which makes it widely used in highway bridge and urban bridge. Especially in urban bridge engineering, a new combination of beam-arch, beam and arch combining in transverse direction of bridge, has been invented and more and more used besides the conventional combination form of beam and arch combining in longitudinal direction of bridge, which is more beautiful but also more complicated for design and construction.

Abstract: Bridge piers generate local destruction at impact point after suffering medium and low speed impact, and then their bearing capacities decrease a lot. Based on the formula in code, this paper used ANSYS to analyze surplus normal section load-carrying capacity of reinforced concrete bridge piers with notches in different sizes. The relation curve between axial bearing capacity of piers and scaling area of concrete was obtained. After comparing with formula in code, a new formula was obtained, which can be used in calculating surplus normal section load-carrying capacity of chipped bridge piers. In addition, damaging process of chipped bridge piers under axial pressure was simulated accurately by ANSYS.

Abstract: This paper describes working performance of the pressed flanges with reinforced plate .Based on the elastic stability theory and elastic-plastic stability theory ,it puts forward the analysis model of the local stability of the pressed flanges by using energy principle .The value of the critical stress is obtained .It cheeks the analysis result with the experiment result.

Abstract: In order to research the fatigue behaviors of the welded rib-to-deck connections in steel orthotropic bridge deck, 14 rib-to-deck connection specimens are designed considering the weld types, butt gap, welding method, and loading position as parameters. Fatigue test are carried out to obtain the fatigue loading cycle times of each specimen under different stress range. Based on the statistical regression analysis, the S-N curves and fatigue classification of the rib-to-deck connections welded with fillet weld and partial penetration weld are obtained respectively. The test results show that, the initial fatigue crack of the fillet weld is prone to appear at the weld root of the rib, while the initial fatigue crack of the penetration weld is prone to appear at the weld root of the deck.

Abstract: More and more pre-stressed concrete box-girder bridges with corrugated steel web are being realized in the world due to their advantages over the traditional concrete box girder bridges. Characteristics of corrugated steel web technology were introduced briefly in this paper, and its application in Juancheng Yellow River Bridge was also presented. Calculations on the shear buckling strength of corrugated steel web for Juancheng Yellow River Bridge were performed by the use of design code of Japan. Based on the analysis results, a reasonable way to determine the sizes of corrugated steel web is proposed, and it will provide help for designers when performing a design of pre-stressed box girder with corrugated steel web in China.