1. A Comparison of the Fire Performance of Prestressed Concrete Double T-beams using Design Provisions and SAFIR
By:
Nickolas Hatinger

2. Overview Introduction Structural Models Design Provisions SAFIR
Results
Conclusions

3. Introduction Prestressed/Precast Industry Buildings Parking Structures
Shopping Centers
Prestressed concrete double T-beams
Span-to-depth ratio
Aesthetics
High-quality manufacturing
Constructability
Low-maintenance

4. Structural Models 2 prestressed concrete double t-beams
PCI 10DT24+2 (40 ft. span)
PCI 12DT32+2 (50 ft. span)
Simply Supported
Normal Weight Concrete
Carbonate Aggregates
L = 100 psf and D = self-wt

5. Properties and Dimensions

6. Properties and Dimensions

7. Design Provisions American Canadian European ACI 318, ACI 216.1, PCI
CSA CAN3-D-2.10, CPCI
European
EN , EN
NIST, (2005)

8. American Codes Tabulated Data Simplified Calculations
Beam: Cover, restraint, aggregate, beam width or cross-sectional area
Slab: Concrete type, thickness
Simplified Calculations
Temperature plots: 1,2,3 & 4 hrs
Material property plots
Load Combination: 1.2D+0.5L

9. Canadian Codes Tabulated Data Simplified Calculations
Beam: Concrete type, area of beam, cover
Slab: Concrete type, thickness
Simplified Calculations
Temperature plots: 2 hr (ACI for 1, 3, and 4 hr)
Material property plots
Load Combination: D+L
NIST, (2005)

10. European Codes Tabulated Data Simplified Calculations
Beam: Beam width, avg. axis distance, web thickness, beam type
Slab: Thickness
Simplified Calculations
Temperature plots: 1,2,3 & 4 hrs (ACI 216.1)
Material property equations
Load Combination: D+0.9L
Advanced Calculations
Guidelines for performance-based design

11. SAFIR2004 Thermal-mechanical analysis computer program
Finite Element Method (FEM)
Nonlinear material properties
FR of structural members or assemblies

12. Results 10DT24+2 FIRE RESISTANCE (hr.) Code: American Canadian
European
Tabulated:
1 1/2 1
Simplified Calculations:
SAFIR (min): 64 60 61
12DT32+2
FIRE RESISTANCE (hr.)
Code:
American
Canadian
European
Tabulated:
1 1/2 1
Simplified Calculations:
SAFIR (min): 92 86 87

13. Conclusions Codes vs. Codes SAFIR vs. Codes
Tabulated Data for the Canadian code was slightly conservative
Simplified Methods were identical
Slabs governed tabulated fire ratings
SAFIR vs. Codes
10DT24+2 consistent
12DT32+2 diverge

14. Questions