Applied Mechanics and Materials Vols. 501-504

Abstract: this article through the detection of Tong Jia Bridge, grasp the present situation of bridge structure and disease, and evaluate existing technical conditions to provide technical basis for the repair and reinforcement of the bridge in the future.

Abstract: As the span became longer and the accumulation of service period of bridges, the problem that deflection of main span has also clearly emerged. To reduce long term deflection of large-span prestressed concrete continuous rigid frame bridges, tendon group-additional bending moment influence matrix method is proposed to optimize the design of prestressed reinforcement. Based on elasticity assumption, an optimum prestressed tendon arrangement can be derived by least square method. The new design is tested to be effective considering shrink and creep effect which fulfills the practical application.

Abstract: This paper presented the deterioration condition and strengthening measures of a prestressed continuous box girder bridge. Finite element model of the bridge was built and condition was assessed according to current codes. Strain and deflection were measured through loading test to assess the stiffness in-service and the carrying capacity of the strengthened bridge. The results indicate that the carrying capacity limit state and serviceability limit state of the bridge are improved.

Abstract: In this paper, based on the drawing of an actual project, the dynamic responses of reinforced concrete piers under impact loads of mass objects were researched by using the finite element analysis software ANSYS/LS-DYNA. A common node separate model was adapted to the dynamic responses. The results indicated that vibration frequency at the top of pier column along the transverse direction was more than that in the impacted position under the action of impact. And after analyzing displacement time history curve and maximum displacement at different parts of pier column, the position with maximum displacement in different working conditions was summarized.

Abstract: Damage identification of a T-beam bridge which contains five T-beams is conducted based on distributed long - gauge strain mode theory, considering the damage and aging problems of widely used simple-supported reinforced concrete T-beam bridges. Assuming that the damage occurs in the different T-beams, the normalized strain mode is used to identify the damage. The sensitivity of the normalized strain mode of each T-beam and change rule of strain mode curve is studied at the same time. It is effective to apply modal strain amplitude variation degree to detect damages. If sensors are arranged reasonablely, a good damage identification can be obtained by utilizing distributed long-gauge strain mode theory even if the damage is slight.Some suggestions are given for the sensor arrangement and health monitoring of this kind of bridge when using the distributed long-gauge strain mode theory at last.

Abstract: Based on finite element theory,Study on temperatrue field under the using of cooling pipe for massive concrete pile in shahe bridge by using MIDAS/CIVIL.Analysis of various factors effect to the temperature field, stress field and the temperature gradient of massive concrete pile,which included in inlet water temperature and the water flow, proposed the control indicators of cooling pipe design.

Abstract: Anti-seismic property was essential in the progress of bridge designing and construction due to destructive power of earthquake disaster and increasing span of bridge. This paper elaborated theory method of analysis, taking five spans continuous cable-stayed bridge which was half floating system as an engineering background, and using method of special finite element analysis to calculating dynamic characteristics and seismic response respectively which also considered longitudinal limit damping and stiffness of cable under longitudinal, transverse, vertical and three-dimensional seismic oscillation. Fundamental frequency of cable-stayed bridge was affected significantly with considering longitudinal limit damping, so connection measures would be determined reasonably in designing and analyzing anti-seismic property of long-span cable-stayed bridge. When response spectrum analysis was adopted, longitudinal and vertical displacement were larger than lateral displacement under longitudinal seismic oscillation, lateral seismic oscillation only affected the structural lateral displacement, and vertical seismic oscillation affected vertical and longitudinal displacement.

Abstract: A new kind of combined finite element named three-dimensional virtual laminated element and its deduce process is introduced. The new finite element was proved to be convenient, accurate and efficient in the calculation of bridge structures by a modal test and corresponding numerical example. Then some research and discussion were done, which show that with small modal construction scale being comparative with beam element, the static and dynamic spatial behavior of complicated structures can be simulated precisely. Furthermore, it is sensitive to structural damages, and more damage information can be obtained than corresponding spatial beam element, which means it is highly promising in the application of structural damage detection.

Abstract: Because the stress concentration usually appears in the plate corner or discontinuity zone, it is necessary to optimize design for local plate of steel anchor beam bearing huge cable force. Based on 3D elaborate finite-element method, the stress distribution of steel anchor beam of cable-pylon composite anchor structure was analyzed. The results showed that the steel anchor beam of cable-pylon composite anchorage structure was safe and reliable, the application of the vertical stiffened plate of the side plate in anchor box and the middle diaphragm efficiently improved the force state of the steel anchor beam, on the other hand the stress conditions of the concrete pylon was more ideal when the steel anchor beam was within the boundary condition of one end of anchor beam fixed and the other end with sliding support.

Abstract: Dynamic test has been carried out to completed road bridge of Nanjiang Port inTianjin. When cars were passing through the bridge, the dynamic deflections, the maximum amplitudes, the relation between amplitude and velocity, the Natural frequency and the damping ratio were gained. Dynamic modulus, vibration characteristics and crack condition of the bridge were determined so as to ascertain the reliability of the bridge.