Examples of Finite Element Models of Steel Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 574

be shown that generally good agreement was achieved between experimen-
tal and numerical relationships. The ultimate failure load observed in the test
[ 6.27 ] was 1474 kN at a deflection of 15 mm, while the ultimate failure load
predicted from the finite element analysis was 1503 kN at a deflection of
14.7 mm. The finite element failure load was 2% higher than that observed
in the test.
6.4 FINITE ELEMENT MODELING AND RESULTS
OF EXAMPLE 2
The second example presented in this chapter is for a small-scale built-up I-
section plate girder steel bridge tested under shear by Nakamura and Narita
[ 6.27 ] . The plate girder was a part of an experimental program investigating
bending and shear strength of steel and partially encased steel-concrete com-
posite plate I-girders. The plate girder is denoted in this study as (T2). The
small-scale plate girder was SS with an overhanging cantilever from one end.
The plate girder had a length between supports of 2.45 m and the overhang-
ing length from the support to loading was 0.9 m as shown in Figure 6.9 .
Similar to plate girder T1, the web of plate girder T2 was 900 mm high
and 6 mm thick. While the flange of the plate girder T2 was 200 mm wide
and 12 mm thick. The web was stiffened by steel plates at the end supports
and the loading positions and also stiffened by intermediate stiffeners as
shown in Figure 6.9 . The plate girder was restrained laterally at the end sup-
ports to resist lateral-torsional buckling. Tensile coupon tests were con-
ducted to determine the yield and ultimate tensile strength of the steel
used, which were 372.3 and 511.4 MPa, respectively, similar to plate girder
T1. The plate girders were loaded at two points, as shown in Figure 6.9 , with
the loading between supports equals to 0.7 the applied load and loading near
the edge of the overhanging cantilever equals to 0.3 the applied load, which
subjected the plate girder to high shear forces. Strain gauges were used to
measure the strains in the plate girder section, and displacement transducers
were used to measure the span deflections at the higher load location
between supports during loading. The strain at the web center was greater
than other parts and, after the tension field appeared, the stress concentrated
around the web center. The diagonal tension-field action was clearly
observed in the test T2. No damage was found in the flanges. The main fail-
ure mode was buckling owing to shear stresses. The load-deflection relation-
ship, load-strain relationships, and the deformed shape at failure were
observed in the test.