Vulnerability assessment of reinforced concrete structures for fire and earthquake risk - Seismic Risk Analysis and Management of Civil Infrastructure Systems - page 370

Solids plot
Temperature plot
Time: 1800 s
828.70
726.01
623.33
520.64
417.95
315.26
212.58
109.89
7.20

(a) (b)

14.5 Temperature distributions on a cross-section of a column 30
minutes after the fi re started: (a) section with no seismic damage and
(b) section with seismic damage.

mation will cause eccentric loading on the structural columns (i.e. P - Δ

effects). Typically, performance of the building would degrade, when P - Δ

effects are present. In this study, since the residual lateral displacement of
the building, measured during the test, was nearly zero, P - effects are not

included in the analysis. For a worst case scenario, this building would result
in less fi re resistance after the earthquake, should the structure have expe-
rienced such a residual drift. More detailed information on the results of
the analysis of the six-storey building in fi re following the earthquake can
be found in Mostafaei and Kabeyasawa (2010).

Δ

14.4.6 Main analysis results and observations

Figures 14.6 and 14.7 show the results of the fi re resistance response for the
short corner columns in the fi rst fl oor, Axis X1, of the building before and
after they were damaged by the earthquake. Based on the results of this
case study, the following remarks can be made:

• The fi re resistance of the six-storey building after seismic damage was
considerably less than that before the earthquake.

• Factors contributing to determining the fi re resistance of the building

after the earthquake were mechanical properties, degradation of con-
crete, and the extent of crack and spalling of the concrete.

• Relatively high fi re resistance was available for the building when only

effects of concrete cracks and spalling in the heat transfer analysis were
included in comparison with the case when only degradation of material