1. Subsystem Instability Conditions in Steel Frames Associated with Extreme Lateral Loading
Charlie Burchfield – Univ. of Mississippi
Tezeswi Tadepalli – Univ. of Cal. at San Diego, SDSC
Christopher Mullen – Univ. of Mississippi

2. Overview Introduction Hazard Exposure Preliminary Design Blast
Live Loads
Load Combinations
Beam
Column
Lateral Loads
Blast
Conclusions

3. Introduction
University Of Mississippi is evaluating the blast resistance of moment-frame structures.
Damage Mapping has been developed and applied to RC columns subjected to air blast loading.
Work is currently being done on the performance of steel columns subjected to air blast loading.

4. Multi-Hazard Design and Blast Vulnerability Analysis
Characterize multi-hazard loading parameters
Structural design procedure (IBC LL,DL,WL & EQ)
Seismic design
Defines member capacities
Member capacity curves
Damage levels
P-I curves
Blast damage mapping

5. Hazard Exposure
Source: usgs.gov

6. Hazard Exposure Lafayette County/Oxford, MS Area
Approximately 270 miles from the Gulf of Mexico Coast.
Approximately 150 mile from the southern termination of the New Madrid fault.
Also, several high value buildings within the area.
Federal Court House
Federal Office Buildings
Etc.

7. Hazard Exposure Building Size 3 Story Two 20 foot transverse bays
Three 40 foot longitudinal bays.

8. Preliminary Design
Complete design was in accordance with the International Building Code 2006.
References
ASCE/SEI 7-05
ANSI/AISC

9. Dead, Live, and Earthquake
Preliminary Design
Live Loads
Determine from the “Minimum Uniformly Distributed Live Loads and Minimum Concentrated Live Loads” from IBC 2006
Used “Office Use” and “Ordinary Flat Roof”
Load Combinations
From ASCE 7-05, Load and Resistance Factor Design
Dead
Dead and Live
Dead, Live, and Earthquake
1.4D
1.2D+1.6L
1.2D+1.0E+f1L
f1 = 0.5

10. Preliminary Design
Beam Design
Using AISC
W18x50
7.5”
18”

11. Preliminary Design Column
We looked at an interior column due to it being the worst case scenario.
Determined to be a W8x31
Axial Load Capacity Ratio is 0.75 8” 8”

12. Preliminary Design
Completed SAP2000 Model

13. Preliminary Design
Completed SAP2000 Model

14. Preliminary Design Lateral Loads
Seismic Loading controls even though in a moderately low seismic area.
Developed the seismic load using IBC 2006 and ASCE 7-05.
Applied these loads to a computer model using SAP v.12 to determine moments.
Section size was still efficient.
Capacity Ratio increased from 0.75 to 0.77 for an interior lower level column

15. Preliminary Design
SAP 2000 view of lateral load displacements

16. Blast Blast Pressures are estimated New Load Case developed
Leads to acquiring standoff distances and charge weights.
New Load Case developed
Using a Military Technical Manuel, TM5-1300, “Structures to Resist the Effects of Accidental Explosion.”

17. Blast
The threshold of acceptable blast resistance can be determined by considering alternate pressure scenarios and column and beam damage levels.
Severe
Moderate
Slight
No damage

18. Acknowledgments Department of Civil Engineering
At the University of Mississippi
Subcontract from the Department of Homeland Security-sponsored Southeast Region Research Initiative (SERRI) at the Department of Energy's Oak Ridge National Laboratory.

19. THANK YOU!