Presentation on theme: "Charlie Burchfield – Univ. of Mississippi"— Presentation transcript:
1Subsystem Instability Conditions in Steel Frames Associated with Extreme Lateral Loading Charlie Burchfield – Univ. of MississippiTezeswi Tadepalli – Univ. of Cal. at San Diego, SDSCChristopher Mullen – Univ. of Mississippi
3IntroductionUniversity 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.
6Hazard 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 HouseFederal Office BuildingsEtc.
7Hazard Exposure Building Size 3 Story Two 20 foot transverse bays Three 40 foot longitudinal bays.
8Preliminary DesignComplete design was in accordance with the International Building Code 2006.ReferencesASCE/SEI 7-05ANSI/AISC
9Dead, Live, and Earthquake Preliminary DesignLive LoadsDetermine from the “Minimum Uniformly Distributed Live Loads and Minimum Concentrated Live Loads” from IBC 2006Used “Office Use” and “Ordinary Flat Roof”Load CombinationsFrom ASCE 7-05, Load and Resistance Factor DesignDeadDead and LiveDead, Live, and Earthquake1.4D1.2D+1.6L1.2D+1.0E+f1Lf1 = 0.5
14Preliminary 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
15Preliminary DesignSAP 2000 view of lateral load displacements
16Blast Blast Pressures are estimated New Load Case developed Leads to acquiring standoff distances and charge weights.New Load Case developedUsing a Military Technical Manuel, TM5-1300, “Structures to Resist the Effects of Accidental Explosion.”
17BlastThe threshold of acceptable blast resistance can be determined by considering alternate pressure scenarios and column and beam damage levels.SevereModerateSlightNo damage
18Acknowledgments Department of Civil Engineering At the University of MississippiSubcontract from the Department of Homeland Security-sponsored Southeast Region Research Initiative (SERRI) at the Department of Energy's Oak Ridge National Laboratory.