Static analyses of bridge structures are currently performed using the finite element method (FEM). Depending on the geometry of the structure and the technically required accuracy of calculations, different levels of discretization of these structures are used in their design. In the design process, beam grillage models (denoted e1, p2), shell models (denoted e2, p2) or shell-beam models (denoted e1+ e2, p3) are often used. Solid models (denoted e3+ p3) are mostly used in advanced analyses, having frequently a scientific character. It is shown that there is an impact of the applied types of the numerical model (i.e., degree of complexity, degree of discretization, accuracy of the model) of the road bridge on the calculated values of bending moments and displacements, which indirectly affects the global safety coefficient of the designed bridge structure. The main purpose of the calculations is to examine the discrepancies of analyzed internal forces and displacements depending of the type of numerical model used. The calculated values are referred to the results taken from the field tests of the existing bridge denoted MS 03, which is a continuous beam structure with the three spans 37:50 + 46:75 + 37:50 m made of prestressed concrete and with variable beam depth. On the basis of numerical simulations, the paper provides author’s recommendations for computer modeling of similar bridges.

In this paper, based on the feasible method and sensors for the full-scale prestressed monitor, the novel optical fiber sensors and the traditional monitoring sensors will be set up into two prestressed concrete beams with the same geometrical dimensions, material properties, and construction conditions, etc. to investigate the working state of the novel sensors and obtain the evolution law of prestress loss of the prestressed feature component under the static load. The results show that the evolution law of prestress loss of the loaded beam under the condition of no damage state and initial crack is the same as the non-loaded one; however, the prestress loss increases with the increase of time under the situation with the limit crack. The total loss of the prestressed beam with the limit crack is 36.4% without damage. The prestress loss of the prestressed beam under the static load increase with the development of the crack (injury).

This paper reports an experimental on the flexural performance of prestressed concrete-encased high-strength steel beams (PCEHSSBs). To study the applicability of high-strength steel (HSS) in prestressed concrete-encased steel beams (PCESBs), one simply supported prestressed concrete-encased ordinarystrength steel beam (PCEOSSB) and eight simply supported PCEHSSBs were tested under a four-point bending load. The influence of steel strength grade, I-steel ratio, reinforcement ratio and stirrup ratio on the flexural performance of such members was investigated. The test results show that increasing the I-steel grade and I-steel ratio can significantly improve the bearing capacity of PCESB. Increasing the compressive reinforcement ratio of PCEHSSB can effectively improve its bearing capacity and ductility properties, making full use of the performance of HSS in composite beams. Increasing the hoop ratio has a small improvement on the load capacity of the test beams; setting up shear connectors can improve the ductile properties of the specimens although it does not lead to a significant increase in the load capacity of the combined beams. Then, combined with the test data, the comprehensive reinforcement index considering the location of reinforcement was proposed to evaluate the crack resistance of specimens. The relationship between the comprehensive reinforcement index and the crack resistance of specimens was given.