General Mitchell International Airport

PROJECT OVERVIEW

Hinman contracted with Engberg Anderson (EA) to provide blast protection services for the renovation of the Baggage Claim building at the General Mitchell International Airport (GMIA) in Milwaukee, WI. The building was renovated to accommodate the change in airport security after the World Trade Center attack. Repairs to the main façade of the baggage claim building included the installation of large glass curtainwall systems and ribbon windows supported by precast panels as an exterior façade. In brief, the goal of the Hinman’s scope was to ensure that if local damage occurs, the structure will not collapse or suffer damage disproportionate to the original cause. Making these upgrades allow for efficient evacuation, while minimizing occupant injuries. Ultimately, the airport defined two threat types from which Hinman based its assessment.

Hinman performed non-linear dynamic analyses to determine proof-of-concept designs for the window systems and precast panels which would result in less than 10% façade failure, and no structural collapse.

HINMAN SOLUTION

Hinman worked with the client and design team to determine reasonable protection levels within the project budget. Ultimately, it was determined economically unfeasible to protect the entire structure and façade from damage under the defined threats. Because of this, the focus for the upgrades were on the new perimeter structure and replacement façade systems. To aid the client decision making process, the team evaluated multiple cost-benefit options in the early stages of design. Hinman performed non-linear dynamic analyses to determine proof-of-concept designs for the window systems and precast panels, which would result in less than 10% façade failure and no structural collapse.

Additionally, Hinman performed a perimeter barrier study. This study included a vehicle approach speed analysis to determine possible speeds at impact for different vehicle sizes. After evaluating acceptable protective barriers, the client could decide if they wanted to spend their budget on perimeter barriers. In the end, the client decided to focus its available budget on the blast hardening of the façade renovation.

Hinman presented its preliminary analysis and provided a 60% and a final report. The reports included a summary of the entire design process. Also, they presented relevant background information on blast analysis, levels of protection, and design results. The results included element sizes and reactions for proof-of-concept designs and their expected level of damage under the defined threats. Lastly, we submitted figures showing a 3D model of the building detailing contour plots of the blast pressures on the building as well as the extent of expected façade damage.