According to the unified theory of general concrete filled steel tube, this paper puts forward a constitutive relationship model of the self-stressed concrete filled steel tube, which was verified by experiments and finite element methods. On the basis of the above, the influences on the bearing capacity of self-stressed CFST members were analyzed about the strength grades and magnitudes of self-stress of confined concrete. The results show that the bearing capacity of the self-stressed concrete filled steel tube members will be improved with the increase of the magnitudes of self-stress and concrete strength grades. Compared to the general CFST in the same condition, the maximum of the bearing capacity can be approximately enhanced 20%.

The bridge infrastructure is critical to both political and economic development and Building Information Modelling (BIM) is now an innovative technology for bridges’ planning, design, construction and operation. However, it is currently difficult to achieve BIM’s practical value in bridge industry due to existing barriers. The focus of this paper is on proposing a new implemented BIM framework for bridge engineering. Particularly, the research project discussed and summarized the barriers which affect effectiveness and collaboration existed in traditional bridge project delivery and proposed a detailed BIM framework based on the traditional workflow to embrace collaboration and interoperation in the whole lifecycle of a bridge. The framework can significantly facilitate integrating BIM tools and practices, and increase the collaboration and productivity throughout the whole process of a bridge.

A method of prefabricating beam on bridge floor is sometimes employed in mountain difficult terrain. Four forms of longitudinal pedestal layout and three analysis cases obtained by orthogonal analysis method were drawn up, the mechanical behavior of the tool girder were studied by the finite element software and the role of deck pavement for tool girder was discussed. The results show that when the end of pedestal was situated in mid-span, the tool girder will reach the most disadvantageous status. Moreover, reinforced concrete deck pavement not only can improve the stiffness and integrity of the tool girder, but also can effectively decrease internal forces and deformations of the tool girder.

Based on the constitutive relationship model of general concrete filled steel tube, and combining with the results and theoretical analysis of several self-stress concrete filled steel tubular specimens, the constitutive relationship model of self-stress concrete filled steel tube was established by introducing an improvement coefficient of concrete strength related to self-stress level. The calculations of specimens’ bearing capacity with different sectional steel ratios, values of self-stress and concrete strengths were performed, which were in a good accordance with those of experimental values.

Taking deformation of the main arch under dead load as the arch alignment control target, the overall cable force and pre-camber of multi-rib arch were calculated by zero-order optimization method. According to the installation sequences of arch segments, taking deviation of cable tower, cables in one-time tensioning method and the section stress of arch chords as constraint conditions, the cable force and pre-camber for every segment were calculated by iterative method. This method is applied to the erection of a 400m steel truss arch bridge with three ribs, the calculated values of cable force are anastomosed with the measured ones, and the precision of arch alignment is high.