SGH performed analyses in accordance with the General Services Administration (GSA) guidelines for blast-resistant design of federal buildings. We designed structural strengthening to bring the building up to GSA Service Level 3a for Level C loading.
Our glazing analysis included predicting glass breakage and hazard indexes created by glass breakage. We investigated numerous window sizes at various distances from the selected detonation locations. SGH recommended means to enhance the performance of the glazing to reduce the hazards to levels acceptable under the GSA guidelines.
We also analyzed the window support system to determine whether it could support window reactions and the direct application of blast impulses. SGH performed materials testing to determine strength of the existing aluminum alloy mullion system and performed a nonlinear time history analyses to evaluate adequacy of existing mullions. For those window support components that could not support the reactions within acceptable deformation limits, we developed reinforcement concepts to reduce deflections and maintain appropriate levels of ductility in the wall framing system.