Applied Mechanics and Materials Vols. 361-363

Abstract: Based on a long-span pre-stressed concrete continuous rigid frame bridge, the Chaoyangsi bridge, the influence on stress and deformation of the girder caused by different closure temperature was analyzed. With the aided platform Midas/Civil, comparative analysis of three different closure temperatures was carried on to determine the reasonable one. It is concluded that different closure temperature has important influence on girder stress, but the most dangerous stress combination of girder under serviceability limit state could be taken as remain the same. Though different closure temperature has little influence on the displacement of girder, it is recommended to pay highly attention to the influence on the mid-span vertical displacement when doing the formwork. And finally this article puts forward some effective measures to prevent and reduce the temperature effect.

Abstract: In this thesis, a dynamic analysis model is established that subjected to a series of moving harmonic loads, and the analytical solution of the dynamic response is deduced based on the mode superposition method. Based on this analytical solution, a program is made to calculate the vertical dynamic response of simply-supported beam. The calculation results show that the analytical solution is reasonable and correct. When the harmonic frequency is near to the fundamental frequency of the simply-supported beam, the resonance phenomenon will occur. The dynamic response of the beam will decrease as the speed increases, and the presence of damp can suppress the vibration of the bridge.

Abstract: Based on a collision analysis between the fixed middle girder and the 2-span continuous girder in longitudinal direction, motion equations of the girder and the pier are established by mode decomposition method. Displacements’ relationship at the collision interface is used to establish the equation about the collision force, and Duhamel integrals in the equation are eliminated so as to get a 6 order homogeneous ordinary differential equation about the collision force. Then an approach to solve the equation is put forward. The analysis results show that the time history curve of collision force is a half sine waveform, and the initial velocity of girder towards pier top is proportional to the peak collision force but has nothing to do with the duration of collision.

Abstract: The FRP slab bridge in this paper is modeled using the finite-element method to predict its modal characteristics. The interaction between the vehicle and the bridge is simulated by using a 3D vehicle-bridge coupled model considering the roughness of the bridge road surface. The dynamic response of the bridge is obtained in the time domain by using an iterative procedure employed at each time step. The influences of vehicle velocity, vehicle rigidity, and bridge surface roughness are investigated.

Abstract: A theoretical analysis model to calculate the spherical bearing rotational torque is established based on two assumptions: a) The spherical cap suffers uniformly distributed pressure along the convex surface, pointing towards the center of the sphere; b) The pressure on the rotating plate imposed by the spherical cap flat surface is distributed as a right trapezoid. Compared with the test results, it can be found that the value calculated according to the theoretical formula is closer to the experimental value than that calculated according to the code. Keywords: spherical bearing, rotational torque, bearing design, bearing test.

Abstract: Due to limitations of construction conditions, the swivel construction method is the preferred even required program across the highway and railway bridges. The constant contained eccentricity of swivel bridge cantilever state has a great impact on the overturning stability of swivel process. Combined with the T configuration swivel bridge engineering instance, based on the basis of data collected loads, loads theoretical model, in line with the objective variation and the scientific process and selecting the representative value of the load was explored, the cantilever pouring weight corresponding probability distribution model was analyzed, and the impact to the stability of the bridge swivel construction process was studied. The analysis of data can ensure the bridge maximum cantilever state security, as well as to provide the basis for command and decision-making of the swivel stage.

Abstract: Chongqing Chaotianmen Bridge is by far the world's largest three-span continuous half-through double-layer steel truss tied arch bridge. Risk evaluation and risk analysis are made to the bridge during construction period. At the same time, various measures are taken to avoid construction risks and accidents. The principal line of risk controls is clear with reasonable control measures. Chongqing Chaotianmen Bridge was completed and available for traffic on April 29, 2009, its various technical and quality indicators are in accordance with design and specifications.

Abstract: Scientific and integrated index system is a basic approach to accurately assess actual structure state of inservice arch bridge. It could provide clear evaluation guidance to assessment work of existing bridges. What is more, it is aimed to avoid or reduce erroneous and omission judgement phenomenon of bridge damage assessment by the grassroots-level maintenance workers. Based on summation of variety common damage in common arch bridges, this paper adopts AHP (analytic hierults are aimed to provide effective method and basis to long-term, persistent damage evaluaarchy process) method to establish arch bridge superstructure damage evaluation model with structure member (or component), the restion of inservice arch bridge.

Abstract: Anchorage zone of tower is a key part of cable-stayed bridge. Some factors such as powerful local concentrated forces, anchor forces from prestressed steels and weaken factors from hole make this area in complicated states. Analysis of strength performance at the anchorage zone of cable-stayed bridge tower has been attracted attention in bridge engineering. Full-scale model test and force analysis was carried out when a typical cable-stayed bridge was selected as the research object. Three stress states of anchorage zone are consider, that is under prestressing, under cable forces in completion state and under maximum cable force. Analysis of stress distribution and force transmission route in these states will provide a scientific basis for design and research work for the future.

Abstract: The temperature deformation of Jiashao Bridge is a serious problem. In order to solve this problem effectively, a kind of rigid hinge structure is adopted in the middle of the bridge. Unit sparse plate bridge expansion joint for multi-direction-displacement is installed on the rigid hinge of this bridge. Vibration reduction tests are needed to verify the performance of the expansion joint and the service condition of the bridge structure. In this paper, a finite element analysis of the rigid hinge expansion joint is performed and a vibration reduction test platform is designed.