LIVE LOAD DISTRIBUTION ANALYSIS IN CURVED REINFORCED CONCRETE BRIDGE
Bridges; Live Load Distribution Factor; Approximate Methods; Finite
Element Method.
Nowadays, due to the density of cities and the demand for infrastructure,
the need to build bridges and curved viaducts has intensified. However, the
structural analysis of this bridge deck geometries still needs more contributions,
especially in optimization of load distribution in this type of deck or in the
comparison between the use of straight and curved girders, in beam and slab and
box girders bridges. Therefore, the main objective research is analyze the
behavior of 3 different structural systems of curved reinforced concrete bridges,
evaluating the bending moment live load distribution in the most critical
longitudinal position of the structure. To identify this position, the influence lines
were determined as a function of the radius of curvature and the length of each
bridge studied. Afterwards, 15 numerical models were constructed using FEM by
CSI Bridge V17 program and an analysis of existing analytical models for curved
beam and slab bridges (V-Load method) and curves box girder bridges (M/R
method) was performed in order to evaluate the variation of the live load
distribution varying the curvature of the bridge centerline, the existence or not of
support diaphragms and the structural analysis method. All the studies were
performed using Brazilian truck load “TB-450” defined by NBR 7188: 2013. The
analytical methods presented overestimated results in all cases analyzed for the
outside girders. The live load distribution of bending moment is optimized through
the insertion of support diaphragms, in bridges wtih tee beams, such distribution
presents a greater variation of load share than in bridges with box girder section,
in which there is an approximate equal distribution. In addition, it was found that in
all structural systems, with increase of the curvature, there is an increase in the
load distribution factor at the outside girder.