Behavior of Steel Building Structures with perimeter mrfs under
fire loading effects
Summary:
This paper presents a fundamental approach and primer
for simulating the behavior of steel building structures
subjected to fire loading. A 10-story office building
located in Chicago was designed according to current U.S.
building codes and design specifications. The structural
layout consisted of interior gravity frames and perimeter
moment resisting frames (MRFs), which is typical of steel
construction in the U.S. The complete 3D building structure
was modeled using several 2-node beam (B33) elements for
the steel columns and beams, and 4-node (S4) shell
elements for the concrete floors.
The 3D structure model was analyzed for two different
fire scenarios: (i) corner
compartment fire, and (ii) complete story fire. The analyses
were conducted using: (i) the modified RIKS (arc-length
based) analysis, and (b) the nonlinear implicit dynamic
analysis approaches. The analytical results indicated
that the thermal expansion of the floor system causes
large out-of-plane displacements and inelastic stresses
in the perimeter columns, but they do not undergo inelastic
buckling failure or collapse. Failure occurs by inelastic
buckling failure of the interior gravity columns because
they are much lighter sections than the perimeter columns.
The inelastic buckling of interior gravity columns has
a significant influence on the
overall behavior and collapse of the complete building
structure. The normalized story capacity of the building
structure can be predicted reasonably using the normalized
axial load capacity versus failure temperature curve for
heated columns with ambient columns above and below.
Format:
Pages : 12
Size: 580 kb
Author : AMIT H. VARMA, ANIL AGARWAL, SANGDO HONG, KULDEEP
PRASAD
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