2.7 USE OF HILTI PROFIS SOFTWARE
Post-Installed Reinforcing in Fire Conditions 2023
Conc . cover
c b mm
Bar length
l d , fire in
Conc . temp . θ ° F
Bond stress
t fire ( θ ) psi
Bond strength
N a , fire ( θ ) lb .
60 0.36 620 509 472 70 0.76 513 509 472 80 1.15 433 509 472 90 1.54 380 509 472 100 1.94 340 509 472 110 2.33 300 509 472 120 2.72 300 509 472 130 3.12 253 509 472 140 3.51 253 509 472 150 3.91 253 509 472 160 4.30 220 509 472 170 4.69 220 509 472
180 5.09 220 509 472
⇩ ⇩ ⇩ ⇩ ⇩
590 21.23 220 509 472
2.7 USE OF HILTI PROFIS SOFTWARE
The determination of the temperature in the concrete member can be very difficult , especially in cases where the temperature is variable over the bond length of the adhesive . This occurs when the geometry of the connection is occurring in beams and columns , instead of just walls and slabs , and when the fire exposure is on more than one face of the concrete . The temperature curves from ACI 216.1 are very basic and only consider fire exposure from one face of the concrete . As part of the Hilti Profis Engineering Suite , the Concrete-to-Concrete module has been updated to include fire design provisions . The calculations will be possible for many different configurations including slab-to-slab , slab-towall , etc . Finite element modeling is used which considers the geometry , the fire exposure from many different faces , and considers the mass of the concrete and steel reinforcing to distribute temperature
As such , there may be differences in the temperature determination between a hand calculation with ACI 216.1 figures and the Profis software . Contact Hilti for questions or for a demonstration on this innovation .
600 21.62 220 509 472 610 22.02 220 509 472
Total 26,441 lb .
• In this case there were 56 segments at 10 mm per segment for a total embedment of 560 mm or 22.02 in .
• The accumulated bond strength from each segment totaled 26,441 lb . which > f y
∙ A se , N = 26,400 lb .
• l d , fire = l d
= 22-inch
• As a shortcut , since the value of t fire ( θ )
= 690 psi in the warmest section of the concrete ( where c b
= 50mm in Step 3 ) is greater than t equiv
= 509 psi , it could have already been determined that the ambient temperature development length controlled in lieu of the iterative calculation .
May 2023
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