The superstructure rotation method (SRM) has been widely used in recent years due to its rapid construction, low cost and less impact on existing traffic.This paper focuses on construction method and the key parameters related with large angle synchronous rotation construction of T-shape curved rigid frame bridges, taking two bridges of the Wuyi Expressway over the Chengdu-Kunming Railway as the engineering background.The results show that the construction methods used in this project can accomplish the realization of complexed synchronous rotation execution of T-shape curve rigid frame bridge. The construction methods consist of the installation process of ball joint, the design of traction system, accuracy control method and rotation control strategy.The friction coefficients from practical measurements were compared with the analytical ones from existing formulas, and it shows that the calculation method can give good predictions for the friction coefficients at the SRM of curve rigid frame bridge.Finally, the key technologies and determination of key parameters applicable for large angle synchronous rotation construction of curve T-shape rigid frame bridge are summarized. Furthermore, the research results in this paper can provide technical recommendation for the construction of the similar bridges.

To address the limitations of mechanical shear connectors, adhesives are used in this research as shear connectors of steel-concrete composite beams (SCCBs). Several groups of bending tests were conducted to compare the flexural behavior of bonded and mechanical SCCBs. Moreover, the results show that the failure modes of the bonded SCCBs mainly include yielding of the bottom flange of the I-beam and the cracking of the concrete bottom surface, local detachment between the two bonding surfaces and the crushing of the concrete slab at the top surface. The rigidity of the bonded SCCB is higher than that of the mechanical one. In addition, the ultimate load of the bonded SCCB connected by 6 mm thick epoxy resin is the highest, which is about 16.8% higher than that of mechanical one. Furthermore, increasing the adhesive layer’s thickness can improve the adhesive performance to a certain extent. Thus, it is suggested that the adhesive thickness should exceed 4 mm, and 6 mm is the optimal. In addition, as local detachment of the adhesive layer occurred in this test, further research can be carried out to avoid such damage.

The dampers of cable-stayed bridges play a crucial role in bridge seismic resistance. Traditional research requires a large number of trial calculations of damper parameters, and the application of machine learning methods to optimize the seismic performance of dampers in cable-stayed bridges has a great significance. This article is based on the parameter analysis data of dampers for a single tower cable-stayed bridge. Firstly, the advantages and disadvantages of central composite design and comprehensive experimental method were compared and analyzed. Then, the response surface fitting method was optimized using support vector egression. Finally, the optimal damper parameters were studied using particle swarm optimization algorithm. Analysis shows that there is significant nonlinearity in the structural response under earthquake action. The use of support vector machines and particle swarm optimization algorithms can accurately and efficiently fit and optimize damper parameters. From this, it can be concluded that the machine learning method combining support vector machine and particle swarm optimization has good accuracy and applicability in optimizing the seismic performance of cable-stayed bridge dampers, and can be further extended to other research fields.