The pile-soil dynamics is an interdisciplinary studies of structural, geotechnical and vibration engineering in the existing bridge. Traffic load model, the developments and status in the existing bridge were reviewed and introduced. The main content and characteristic of pile were summarized in clay, sand, silt and red clay. Main problems existed in the study of cyclic loaders on the piles were discussed. The prospect of future research trend in this field was also examined.

Calculating the local stress for the anchorage zone of each part in the tooth plate by establishing two kinds of finite element model: considering concrete effect and not considering concrete effect. The result of the comparative analysis of the two models shows that the local stress considering the concrete effect is smaller than that not considering the concrete effect and the maximum difference is about 170 MPa. The difference is not the same in different parts of the tooth plate. Although the design will be tend to be safe for not considering the concrete effect, the size of the tooth plate may increase. Therefore, in order to reduce the weight of the tooth plate , the concrete effect should be taken into consideration in the design.

Reported researches rarely focus on dynamic stress concentration factors (SCF) of tubular joints between the chord and brace, where the chord is a square pipe, and the brace is a circular pipe. Tubular joints between a square pipe and circular pipe are widely applied in spatial structures as a support structure. Therefore, tubular joints of welded steel pipes under axial loads were studied numerically for determination of dynamic stress concentration factors (SCF). Finite element models were setup for a total of 165 tubular joints with various configurations, obtaining dynamic stress distributions of each model along the joint. Dynamic stress concentration factors on the brace and the chord were extracted respectively. Relations between sizes of dynamic stress concentration factors between the joint and structural parameters were discussed. The computational model was finally validated by the experimental test. The experimental curve was basically consistent with the finite element at the elastic stage of loading, indicating that the computational model at the elastic stage was very accurate. The paper mainly studied dynamic stress distribution of the tubular joint of welded steel pipes under an excitation load at the elastic stage, so the finite element model could be used to replace experimental test. SCF was 180° symmetric under different parameters. This angle was located at the crown point of tubular joints, while the welded steel pipe structure was a symmetric structure relative to the longitudinal plane. In addition, the chord and brace had SCF peaks at the angles of 90° and 270° because the two points were located at the saddle point of the tubular joints. Under angles of 0° and 180°, the SCF had obvious valley values because the two points were located at crown points of tubular joints. Finally, the vibration performance of the tubular joint was also analyzed. Vibration displacement could be reduced obviously through reinforcement of tubular joints with the collar plates. Axial pre-tensile forces would increase vibration displacement on top and bottom positions of the chord pipe. This paper can provide an important reference for the improvement of the dynamic stress concentration of joints of welded steel pipes.

The gray system theory modified by Kalman filtering method is used in the inconsistent between the observed and theoretical values of the segment’s deflection in bridge cantilever construction process. Firstly, get the statistically optimal estimatations of the observed value using Kalman filtering theory, then making it as the initial value, the gray system theory is used to predict the deflection of the next segment, and the formwork elevation of next stage is fixed. As a project example, a prestressed continuous girder bridge in Zhongshan City, Guangdong Province is put forward, respectively using the gray system theory and the gray system theory modified by Kalman filtering method to predict the deflection. According to the comparison from above two methods as well as the closure precision, the conclusion is the gray system theory modified by Kalman filtering can be more effective to reduce the deviation of observed and theoretical values, that means a better bridge linear control.