Executive Summary

The Army National Guard Readiness Center addition is an eight-story joint headquarter building located in Arlington, Virginia. The structure consists of a 43” mat foundation, flat slab concrete floor system with column strips and edge beams, ordinary reinforced concrete shear walls and various reinforced concrete columns.  Typical interior columns are 22” by 22” with variations in reinforcement.  The building features telecommunication centers, joint operations center, general officer suites, an auditorium, conference rooms, gym area, and training rooms.  The Army National Guard Readiness Center has unique triangular shape, which is emphasized with a glass-enclosed staircase in the northern corner that is topped with a distinctive steel tricorn.

For this thesis report, the goal was to investigate and discuss the affects of redesigning the structural system of the Army National Guard Readiness Center from cast-in-place concrete to steel framing.  It was necessary to keep unique architecture and layout of the building relatively unchanged.  A progressive collapse analysis was also necessary due security concerns, given the utility of the building as a headquarters for the National Guard.  The Army National Guard Readiness Center was redesigned from the existing two-way concrete slab and ordinary reinforced shear walls to a reliable and efficient steel structural system.  It was determined that composite steel beams and metal decking would be a viable alternative to the current concrete structure.  Preliminary framing elements were sized using the AISC 13th Edition Steel Construction Manual and Vulcraft’s Steel Roof and Deck Catalog.  A RAM model was then generated to optimize the structural system.  Several lateral force-resisting systems were also considered and after much research it was determined that moment frames would be the most effective lateral system for this building.

Two breadth studies were conducted for this report to determine how the structural redesign affects other aspects of the building.  The first breadth topic was an acoustical study to analyze the transmission loss of the steel structure from the mechanical penthouse to the office areas on the 5T level.  An area below two cooling towers was chosen as the focus for this study.  Once the sound pressure created by the cooling towers was determined, the required transmission loss could be calculated.  A new roof detail was designed and studied.  It was concluded from this analysis that the steel deck and concrete thickness provided was adequate in providing the necessary transmission loss so it is anticipated that there will not be any acoustical issues in the spaces at the 5T level. 

The second breadth study was a construction management analysis that was performed to investigate and compare the cost and schedule of the existing concrete structure and the proposed steel structure.  Detailed takeoffs were used for both systems to determine a cost break down for the material, equipment, and labor costs using R.S. Means Construction Costs Data.  Estimated schedules were generated using time acquired from labor crews and unit amounts.  From this study it was concluded that the concrete structure could be constructed for less than the steel structure, however it was the steel structure that could be erected quicker.