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Curved beams are sometimes used in practical framed structures due to good mechanical properties and artistic design. In a framed structure, curved beams may undergo large displacement and experience nonlinear behavior as same as the other straight slender beam-column members. Thus, a geometrically nonlinear curved beam element plays an important role in the analysis of framed structures with curved beams. However, most existing curved beam elements are not accurate enough and still need several or even dozens of elements to accurately describe the behavior of a curved beam with a large subtended angle. To fill this gap, this paper presents a novel geometrically nonlinear curved beam element based on the element-independent co-rotational (EICR) method. The proposed element can simulate a curved beam using only one single element in the analysis and design of most practical framed structures. Moreover, this element is directly derived in a Cartesian coordinate system and can be directly and conveniently used with straight beam-column elements in nonlinear structural analysis. In this manuscript, the derivation of the proposed geometrically nonlinear curved beam element is detailed and several benchmark problems are proposed to verify its accuracy and efficiency.

Superstructure rotation method (SRM) can optimize bridge construction in terms of reducing impacts on traffic, safety and overall budget. This paper focus on the key scientific problems of the swivel arch bridge, and takes the world’s largest high-speed railway swivel arch bridge on soft soil foundation over Hu-Hang highway as the engineering background. Construction technologies of this project including the installation process, design of the traction system and the precision control method are introduced. Optimum design method of tension force of the tie bars which considering 7 different load conditions during the construction process is proposed. As the key element of the construction of swivel arch bridge, a complete design process of the spherical hinge is present in detail. Exact analytical solution to determine the relationship of radial stress and upper load, which based on the solution of concentrated force acting on the half-plane body in the elastic mechanics, has been firstly put forward and compared with the simplified method recommended by codes. Meanwhile, reasonable ranges of geometric and material parameters have been given and elaborate design flows of the spherical hinge have been presented. Besides, overturning resistance checking design of the spherical hinge during the construction process have been presented also, which are particularly instructive for engineers and designers.

Only few studies have been reported on the flexural behavior of steel-ultra high performance fiber reinforced concrete (UHPFRC) composite beams subjected to negative moment. Addressing this limitation, this paper presents the experimental and analytical studies on the steel-UHPFRC composite beam. Two large-scale beams, including one made of normal-strength concrete (NC) slab and another consisted of UHPFRC slab, experienced four-point bending test to investigate their flexural behavior. In this study, the steel girders and NC/UHPFRC slabs were made composite by embedding the stud shear connections in the pockets that were preformed on the precast slabs. The experimental results showed that the use of UHPFRC slab increased the stiffness and improved the crack control capacity of the composite beam. In addition, the full composite action was achieved in both tested beams, evidencing the sufficiency of the stud shear connectors for the tested conditions. The flexural strength and crack width were calculated through simplified analytical approaches. Good agreement was achieved between the measured and computed values.

External prestressing technology has been successfully adopted for enhancing the load-carrying capacity of beams in bridge engineering. Previous studies on the shear behaviour of externally prestressed concrete (EPC) beams mainly focused on the ultimate shear strength. The post-cracking shear behaviour of EPC beams remains unclear. This study aims to investigate the post-cracking shear behaviour of EPC beams. To this end, nine EPC beams with different design parameters were tested to failure. The investigated parameters included the prestressing condition, shear span to depth ratio, shear reinforcement ratio, and bend angle of external tendons. In contrast to reinforced concrete beams, the EPC beams demonstrated shear tension sliding with concrete spalling failure. The applied prestressing increased the concrete shear contribution by 68%. The percentage of the concrete shear contribution out of the total shear strength of the test beams ranged from 45% to 79%. The post-cracking shear strength reserve ability index, defined as the ratio of the shear strength and shear cracking strength, ranged from 1.72 to 2.96 in the EPC beams. A new ductility index, defined as the ratio of the ultimate deflection and the deflection corresponding to first shear cracking, was used to evaluate the post-cracking deformability of EPC beams. The ductility index of the EPC beams ranged from 3.0 to 7.6, indicating considerable post-cracking deformability. The beam’s stiffness at first shear cracking was 39–81% of the beam’s initial stiffness; the beam’s stiffness at the ultimate state was 18–41% of the beam’s initial stiffness. Finally, the current shear provisions were evaluated by the test results.