O’Hare International Airport


This new air traffic control tower and base building are located at O’Hare International Airport in Chicago, Illinois. The base building is a one-story building with a steel structure and braced lateral system. Coupled with the base building, the air traffic control tower is approximately 245 feet high and consists of a series of reinforced concrete cylinders placed concentrically on top of each other to form a tower. The cab of the tower has insulating panels on metal studs above and below the vision panels. The roof of the tower is a metal deck and concrete on top spanning between horizontal beams. With this in mind, Hinman’s technical approach was first to determine critical threat locations and then calculate air-blast parameters (pressure, impulse, shock front velocity) for these locations. Therefore, each scenario included dynamic non-linear analysis of individual elements and dynamic non-linear analysis of a multi-material window curtain wall system.

Computations were performed using BAM, our in-house program which uses non-linear dynamic structural analysis using energy methods, lumped mass models, and empirical relations developed from explosive test data.


Hinman provided structural analysis in compliance with the air-blast requirements. Overall, we worked with the project team to implement the requirements of the FAA Document 1600.98B Facility Security Management Program. Additionally, we analyzed several representative structural elements for their response to air-blast effects due to the designated explosive threats. Hinman’s technical approach included:

  • Determination of critical threat locations
  • Calculation of air-blast parameters
  • Analysis of individual elements
  • Analysis of window curtain wall system
  • Comparison of results to evaluation criteria, consistent with the required level of protection to determine predicted response

We performed computations using BAM, our in-house program which calculates non-linear dynamic structural analysis by using energy methods, lumped mass models, and empirical relations developed from explosive test data. The scope included air-blast design/analysis computations in support of a 95% complete design submittal. In addition, subcontractor drawings and calculations were reviewed to verify compliance with defined criteria. To summarize our analysis, Hinman submitted a narrative discussing the air-blast requirements and impacts.