Blast Design and Analysis

National Business Park- Building 300 is a seven story office building located in Annapolis Junction, Maryland. It was designed in 2007 and construction was completed in 2009. The structure of NBP-300 is composed of a composite steel system and utilizes four eccentrically braced frames for the lateral system located at the core of the building.
National Business Park- Building 300 was not designed to resist blast, and therefore, were an attack made on the building, heavy structural damage would likely result. For this reason, it will be assumed that NBP-300 will be redesigned as a high risk building for terroristic threats, and as such would be required to meet certain criteria for blast loading. Designing for interior blast has many challenges, as well as many solutions. There is no clear “cookie-cutter” method to designing for blast, which makes it one of the most intriguing and interesting new topics of study. Blast design isn’t new per say, but in the realm of structural design, it has only be in consideration for the last 50 years or so. Although progressive collapse is a major issue when designing for blast, the scope of this redesign will be limited to strength factors only due to time restraints, and redundancy of design will be ignored.

A specific situation has been created for the design. It can be assumed that the greatest threat in terms of explosives will be a briefcase sizes device detonated in the interior of the lobby on the second floor. The UFC -340-02 documents outlining blast requirements were used to identify threat levels, design site security, and find blast loads. The blast load from this situation was calculated and a typical bay located at the lobby location was designed to withstand the blast loading found. Additionally, the façade of NBP-300 was redesigned to allow venting of the interior during the blast. The large percentage of glass currently on the façade could potentially be harmful to occupants when the façade fails.

LS-DYNA Blast Modeling software was used to analyze a critical portion of the original and redesigned structure. A comparative study was completed where the assumed explosive for this situation was detonated in the original LS-DYNA model and the redesigned LS-DYNA model. The intent was to minimize structural damage as much as economically possible through this redesign. By comparing the original structure to the redesign it became apparent that the redesign was highly conservative, but overall, withstood the blast load and incurred very little damage.

In addition to the blast design and analysis, a site redesign was completed. Also, a façade breadth was completed, including a façade redesign with anchored “blowout panel” and a heat transfer study of the new façade.

MAE coursework was incorporated into several aspects of the redesign for NBP-300, including building modeling techniques (AE 597A), a moment connection design (AE534), and a façade design (AE542).

Going into this thesis design, the following goals were set forth and achieved:

Design a typical beam, girder, column, moment connection, and floor system
Use a finite element analysis software (LS-DYNA Blast) to model the effects of blast in the original structure and redesigned structure, and compare the results
Show that designs using hand calculations are overly conservative
Redesign the site of NBP-300 to mitigate large exterior blasts
Redesign the façade of NBP-300 to allow venting of the interior during an interior explosion
Calculate heat transfer through the new façade and determine if the new design is acceptable

Details

Title	Blast Design and Analysis
Pages	63
Language	English
Format	PDF
Size	4 MB
Download Method	Direct Download
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