Examples of Finite Element Models of Steel Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 558

with 6 degrees of freedom per node. The element permitted the end nodes
to be offset from the centroidal axis of the beam. The hangers were modeled
as truss elements (LINK10) with 3 degrees of freedom per node. The deck
slab was modeled using eight-node shell elements with 6 degrees of freedom
per node (SHELL93). The two extreme beams and the vertical supports
were connected by spring elements (COMBINE14). A detailed model of
all the bridge elements was intended, which resulted in higher number of
degrees of freedom. The full model consisted of 10328 beam elements,
17 truss elements, 15672 shell elements, and 8 spring elements, resulting
in 26025 elements and 47024 nodes.
Romeijn and Bouras [ 6.11 ] developed a finite element model of a
tension-tie arch bridge to investigate the in-plane buckling length factor
of the arches. The finite element results were compared with the corre-
sponding values given by Eurocode 3. The modeling of the tension-tie arch
bridge, the bridges' properties, and the solution procedure were described.
Parametric analyses were performed by the authors. The case of one cable
missing (broken cable) was also investigated. The finite element software
Nastran was used to develop the model. Three different bridge geometries
are modeled comprising a bridge with a length of 300 m and a height of
45 m, a bridge with a length of 300 m and a height of 30 m, and a bridge
with a length of 300 m and a height of 60 m. For each of the geometries,
five different cable configurations were modeled with the number of cables
in each arch being m ¼ 1, 2, 3, 5, and 11. The center-to-center distance of
the crossbeams in the deck was 25 m, while the width of the deck is 30 m.
Two different arch inclinations were used comprising the case where the
inclination of the arches is 12.5 with the vertical direction and a vertical
arch configuration. The different cross sections used were cross section
(a), which was the cross section of the main girder having a rectangular
box section with a height of 2300 mm, a width of 3000 mm, and a thickness
of 25 mm; cross section (b), which was a double-symmetrical I-beam with a
height of 2300 mm, flanges 625 mm wide and 25 mm thick, and a web
thickness of 20 mm and was used for the crossbeams in the deck; cross sec-
tion (c), the cross section of the arch, which was a rectangular box section
with a height of 4000 mm, a width of 3000 mm, and a thickness of 60 mm;
and finally, cross section (d), which was a circular hollow section with a
radius of 1000 mm and a thickness of 25 mm. All the cross sections were
modeled using beam elements. The cables of the bridge are modeled using
rod elements. The rods being used had a circular cross section with a diam-
eter of 120 mm. The concrete deck of the bridge was modeled using plate