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TECHNICAL PAPER

main load-bearing component in a building frame, appropriate based columns with and without steel fibers, respectively. Except
fire safety provision must be satisfied. Therefore, it is necessary for the strength and fiber reinforcement, these columns had
to evaluate the response of the SFRC columns under fire similar characteristics, aggregate type, and were tested under
conditions. similar load levels.
P
The advances in numerical models and computational tools,
and an improved knowledge of elevated temperature material 47.5 610 × 508 × 25 steel Plate
properties, have made it possible to determine the fire ties @ 145 mm c/c
resistance of structural members through calculations with 600 4-25 φ 8 mm φ
sufficient accuracy. A review of literature indicates that, while 75
several numerical studies [6, 13, 14] are available in the literature
for evaluating the fire resistance of the NSC columns, very 305
few numerical studies [6, 15] are available for the SFRC columns. 152.5
Moreover, the available numerical models either neglect the 75
305
contribution of the SFRC or use a simplified approach to 3810 2465
account for the contribution and high temperature properties of
the SFRC. Thus, these numerical models do not provide insights
on the fire performance of the SFRC columns. To overcome
some of these drawbacks and to evaluate the fire response
ties @ 145 mm c/c
of the SFRC columns, a numerical model is presented in this
paper. The validity of the model is established by comparing the
temperature and deflection predicted by the model with those
measured in fire tests. Additionally, the behavior of the NSC and 600 610 × 508 × 25 steel Plate
HSC columns under fire exposure is analyzed and compared 47.5
with the fire behavior of the SFRC columns. (All dimensions are in mm)
Figure 1: Geometrical details of the columns tested at NRC Canada.
2. coMPARAtive FiRe PeRFoRMANce oF
Figure 1 shows the geometrical details of the columns. All
Rc coLUMNs the columns were 3.81 m long and had a 305 mm × 305 mm
Kodur et al. , in a collaborative research project between square cross-section. The columns were reinforced with four
[6]
National Research Council of Canada (NRC) and National steel rebars of 25 mm diameter in longitudinal direction, at a
Chiao Tung University (NCTU), Taiwan, carried out a detailed clear cover of 40 mm. The rebars were attached with lateral ties
experimental study on five sets (each set comprising of three of 10 mm diameter at a spacing of 75 mm in 650 mm length
columns) of full-scale RC columns in order to develop fire near the supports, and 145 mm spacing in the middle of the
resistance design guidelines for the use of the HSC. The column height. During the tests, all the columns were exposed
variables considered in the study included concrete strength to American Society for Testing and Materials (ASTM) E119
(NSC and HSC), aggregate type (siliceous and carbonate standard fire from all four sides only in the central 3000 mm
aggregate), and fiber reinforcement (steel and polypropylene portion and were subjected to concentric structural loading
fibers). To characterize and compare the effect of strength, and on the top surface, while the bottom surface was fixed. The
fiber reinforcement on fire resistance of RC columns, the results details pertaining to compressive strength of concrete, ultimate
from the fire test of three different RC columns, designated as capacity, applied load, load intensity, and fire resistance
TNC1, THC4, and THS10, are discussed here. The column TNC1 measured in tests of these three columns are summarized in
is an NSC-based column, whereas THC4 and THS10 were HSC- Table 1.

Table 1: Parameters considered and results for the fire tests on different types of column
ComPREssIvE stREnGtH oF FIRE REsIstAnCE
nAmE oF ConCREtE, f c’ tYPE oF ULtImAtE LoAD LoAD (mInUtEs)
CoLUmn 28 DAY tEst DAY CoLUmn CAPACItY, APPLIED, RAtIo,
P (kn)
P u (kn)
(mPa) (mPa) P/P u tEsts moDEL
TNC1 27.8 40.2 NSC 1728 930 0.54 278 282
THC4 60.6 99.6 HSC 3697 2000 0.54 202 202
THS10 63.2 89.1 SFRC 3349 1800 0.54 239 245

The IndIan ConCreTe Journal | auGuST 2019 9