Influence of concrete strength in live load bending moment distribution in bridges widened
Bridges in concrete. Load distribution factor. Bridge widening. Structural analysis. Finite Element Method.
This research consists of the analysis of the distribution of bending moments and shear forces due to the live load in the beams of straight reinforced concrete bridges that have undergone a process of enlargement of the superstructure. For this purpose, analytical models of load sharing in bridge decks were developed based on the principles of the Leonhardt method and numerical models, using the Finite Element Method (FEM), with the aid of the CSiBridge® program, version 21. Bridge situations with different numbers of beams and with concretes of different strengths in the widening region were analyzed, which allowed to conclude that the distribution of forces between beams of the same geometry fundamentally depends on the strength of the concrete in the widening region and that the greater it is the strength of the concrete in the widening more efforts are absorbed by the new beams and less by the existing beams. In addition, it was found that the increases and decreases in efforts in the beams as a function of the concrete strength follow closely linear functions and, mainly, 2nd order polynomials.