Applied Mechanics and Materials Vols. 204-208

Abstract: The steel tubular arch is hoisted segment by segment through cable crane and the stayed cables are used to maintain stability and balance. The determination of the stayed-cable forces and construction camber value of the erected rib segments becomes the key issue to ensure construction quality and safety. The forward iteration analysis method, which combines finite element method with optimization method as provided in this paper, can easily and effectively determine the stayed-cable forces and construction camber value in the erection of the rib segments, and the stay cables can be tensioned to their target force values only at one time. Finally, the example is demonstrated to prove the correctness and affectivity of the present method. Numerical example indicates that the results based on the method may be used to the backward analysis of the initial state, and that the proposed CM has excellent features of quick convergence rate and best global performance.

Abstract: In order to solve the abutment instability problem of the ChangXin Viaduct in JiLin to YanJi highway, we had the detailed geology survey and exploration of the abutment and its back roadbed, and had also the test of soil bulk density and the shear strength, and the deformation monitoring. The results show that the groundwater runoff and seepage functions for the abutment and its back roadbed are both strong because they are in the slope which in the junction of large diameter group sandstone and mudstone. Because of the two months consecutive rain function, the group stratum became soft in water, and added the combined function of the abutment and its back filled soil, so caused this group stratum sliding under the abutment and its back subgrade, and led to the abutment instability. To prevent the continuing landslide development, and maintain the landslide stability and the security of the bridges and roadbed, according to the causes above, we took the following treatment measures: Dismantling the finished 0th abutment and 1st pier, increasing two holes bridges, so making the abutment away from the landslide area, and at the same time transforming the extending foundation form to pile foundation, so they can reduce the damage function to the original slope body; Appropriately cutting earthwork and lessening weight of the landslide, using antiskid pile supporting baffle in the landslide body, and adopting blind ditch and cutting, drainage ditch to process drainage treatment, all of these ensure the stability of landslide and no adverse effects on bridge foundation.

Abstract: The construction of reservoir is beneficial to improving channel conditions, but at the same time, it also increases the possibility of ship-bridge collision, especially for arch bridge, the navigable clearance of which reduces. Once the collision happens, it will lead to a serious accident, therefore, the construction of anti-collision device is particularly important. “Arc Water Lifting Anti-collision Device” is designed to protect reservoir arch bridge from being hit by ships, which is mainly composed of three parts, that’s collision belt, buoy and oriented well, and it can lift freely with the water level changing. In this paper, this device is applied in Wanzhou Yangtze River Highway Bridge, and it is proved that this new device can meet the security requirements of ship, bridge, and itself when the collision occurs.

Abstract: Many long-span suspension bridges have been built around the world, and many of them carry both of rail and road traffic. Fatigue assessment shall be performed to ensure the safety and functionality of these bridges. This paper first briefly introduces the main procedure of fatigue assessment recommended by British Standard, and then it is applied to the Tsing Ma suspension bridge in Hong Kong. Vehicle spectrum of trains and road vehicles are investigated based on the measurement data of trains and road vehicles recorded by the Structural Health Monitoring System (SHMS) installed on the bridge so that fatigue damage assessment will be more realistic and accurate. Stress influence lines corresponding to railway tracks and highway lanes are established based on a complex finite element bridge model so that an accurate vehicle-induced stress response can be estimated based on them. The fatigue-critical locations for different type of bridge components are identified in terms of the maximum stress range due to a standard train running over the bridge. Finally, the fatigue life at the fatigue-critical locations due to both trains and road vehicles are estimated, and the result indicates the bridge is in very good condition.

Abstract: The risk factors of continuous incremental launching bridge during construction stage are specialized. The risk in incremental launching stage is analyzed and identified. A risk assessment index system is built. A fuzzy comprehensive evaluation model is developed. The results obtained from the risk assessment model verifies the validity and practicality of the developed method by the combination of analytic hierarchy process and fuzzy mathematics theory. Moderate risk assessment results are developed to provide references for incremental launching construction method.

Abstract: Under the background of Liuyang River Bridge, systematical studies of the key technologies of incremental launching control for inclined continuous box-beam bridge are of important theoretical significance and practical engineering value, with the features of incremental launching construction control difficulties caused by vertical curve, skew, steep longitudinal gradient, and with cantilever flange and heavy box girder. The results show that the limitation of dead weight of box girder can be overcome by precast supporting system composed of box-girder precast bearing system and box-girder incremental launching bearing system. The factors of stiffness and weight of main girder should be considered for guiding beam configuration in incremental launching construction, which should choose reasonable stiffness, length and weight, to assure that the negative moment peak of largest cantilever status and a status when guiding beam is on the pier is consistent with the largest fulcrum negative moment during the use state. The predictive value and measured value of stress and deformation of whole process of steep longitudinal gradient incremental launching about inclined continuous box beam are in good agreement. Horizontal traction force of jack, transverse offset of box beam and stress of temporary pier are all be well controlled, satisfying all design requirements, which means that simulation analysis and control of whole process of incremental launching is effective and feasible. The study results offer reference for similar bridges about the whole process of incremental launching construction.

Abstract: Depend on the Cha Ping Bridge on Yan-Ru Highway, through modeling a dimensional, the thesis researches the curved bridge’s force analysis under different radius of curvature and working conditions. Studies shows as follows: 1) as the continuous rigid frame curved bridges exist greater torque, the box girder generates lateral deformation. 2)the lateral deformation is inversely proportional to the curved bridge’s radius of curvature, the larger the radius of curvature is, the greater the lateral deformation is. 3) variation of the radius of curvature has little effects on the longitudinal stress, vertical deformation and vehicle load. The above conclusions can be borrowed for the design and construction of the similar continuous rigid frame curved bridges.

Abstract: The time-varying thermal stresses of a concrete pier are actively studied in this study with the aiding of the commercial package ANSYS. Thermal boundary conditions are utilized to obtain the temperature distribution of the concrete bridge pier. The surface temperature of the pier is measured by using a thermal infrared imager at different time instants. The different boundary conditions are applied to determine the structural temperature distribution and compute the thermal deformation. The made observations demonstrate that the horizontal deformation is much larger than that in vertical deformation due to the influence of the constraints on the top and bottom sides of the pier. The thermal stresses of the example bridge pier are not very large except for the local areas on top of the piers. It is seen that the numerical models can successfully predict the structural time-varying temperature effects

Abstract: Exampled by a test project in Kuche - Akesu express highway engineering of Xinjiang Uygur autonomous region in this paper, it is analyzed that technical and economical rationality of backfilling at bridge abutment with the natural graded gravel mixed with cement of flow state, and the evaluation parameter is introduced by contrast of test projects between conventional technology and the new technology. It lays the foundations of the promotion and development of this technique and the further study.

Abstract: Aizhai Bridge is a stiffening steel truss girder suspension bridge and the main bridge consists of three spans of 242m+1176m+116m. It flies over Dehang Canyon, which is cliffy and steep, the depth between the designed elevation and the ground is 355 meters. In order to overcome the problems happened during the transportation, a new construction plan for the erection of steel truss girder is developed, combining the lifting technology with the cable-tracking transportation. Simply speaking, main cables and hangers are used as bearing structure, the track cables hanged on the hangers are used as transportation track. The transport vehicles system run along the tracking cables to deliver the steel truss girder, and the deck unit erecting system do the lifting job. In this paper, the scale model experiment and full scale model test of the track-cable transferring system are introduced, the design and test of erection gantry for deck unit are described. Finally, the engineering application of the track-cable erecting system is described. The results of experiment and engineering application show that the transportation and erection work of steel truss girder can quickly be completed by using the new construction plan. It is safe and economic solution, and has very broad prospect and practical value for the construction of suspension bridge and arch bridge.