The Effectiveness of Seismically Designed Steel Framing Systems Subjected to Blast Loading

The effectiveness of three different framing systems for seismically designed steel structures subjected to blast loading is investigated. They are: a moment resisting frame (MRF), a concentrically braced frame (CBF) and an eccentrically braced frame (EBF). The blast loads are assumed to be unconfined, free air burst detonated 15 ft from one of the center columns. The structures are modeled and analyzed using the Applied Element Method, which allows the structure to be evaluated during and through failure. Failure modes are investigated through a plastic hinge analysis and member failure comparison. Also, a global response analysis is observed through comparison of roof deflections and accelerations. The impact of structural geometric irregularity is also investigated. Vertical setback and horizontal reentrant corner irregularities are considered for two different blast locations. Finally, the modification to a MRF structure required to prevent any member failure are found as well as the cost of making the structures more blast resistant. A conclusion of this research is that braced frames provide a higher level of resistance to blast loading. Both the CBF and EBF had a smaller number of failed members and plastic hinges compared to the MRF. They also had smaller roof deflection and acceleration. The CBF yielded the fewest number of plastic hinges but the EBF had a slightly fewer number of failed members for the regular structures. Another conclusion of this research is that geometric irregularity has an impact on the response of a structure subjected to blast loading. All three structure types performed better when the source of the blast was on the side of the setback or reentrant corner. This has practical significance in architectural design, placement, and orientation of a high-rise building structure in terms of minimizing its potential damage to blast loading. Finally, it was concluded that by increasing the moment capacity of the perimeter beams of the first four stories by 420% in the weak axis and 100% in the strong axis and 50% in both axes of the columns on the structural face closest to the blast source in the seismically designed moment resisting frame, member failure could be avoided. The modifications increase the material cost of the structure by only 4.5%. Therefore, if an area in the structure can be identified as a potential threat location, it would be practical to design those members to resist blast loads.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Civil Engineering

Grantor dc:publisher

The Ohio State University

Year dc:date

2013

Author dc:creator

• Coffield, Amy K.

Contributors dc:contributor

• Adeli, Hojjat

• Civil Engineering

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=osu1357255039

OAI identifier oai:identifier

oai:etd.ohiolink.edu:osu1357255039