In 2011 we were contracted by a non-governmental organization to provide a Blast Engineering Assessment and Upgrade Designs for their headquarters compound in Iraq. Our goal was to assist the NGO in defining threats, perform an analysis based on those threats to determine existing compound vulnerabilities and to develop retrofit concepts, designs and drawings such that upgrades could be procured and constructed.
We worked with professional colleagues Hollice Stone of Stone Security Engineering (SSE) and Ken Best of bmk Engineering. SSE provided assessment and analysis support while bmk provided cost input and drawing support for the concepts and designs.
The several acre large headquarters compound has a perimeter wall with vehicle access control points, a pedestrian control point and over one-hundred buildings, most of which were considered to be occupied. The target to be achieved through existing or retrofitted buildings was a low level of protection, based on the definition by the US Department of Defense UFC 4-010-01 “DoD Minimum Antiterrorism Standards for Buildings.” The specific threats addressed were from large and small vehicle borne improvised explosive devices (VBIED), RPG’s and rockets.
Most assessments benefit from a site visit, where an engineer on the ground can get a strong sense of the site operations and building function. For this project, bmk attended a pre-bid site meeting, which benefited the PEC team during all phases of the project. Information gained from this visit, combined with other sources of information such as official drawings, satellite photos, site photos, teleconferences and other written materials, was ultimately used to great benefit for the client.
In the first part of the assessment we assisted the client in determining critical threat locations. Using satellite imagery and available city maps, combined with operational discussions and information provided by our client, our engineers were able to identify critical locations and threat scenarios. Using similar methods we were also able to determine the necessary standoff distances from the critical threat locations for the VBIED threat.
Threats of most concern were VBIEDs. Blast loads were calculated on each of the buildings in the compound and a blast analysis of each structure was performed to determine the level of damage and level of protection provided for the existing conditions. To perform this analysis we used appropriate analytical blast and structural modeling tools including ConWep, , BlastX , SBEDS, HazL and VAPO to predict loads, structural and glazing response and collateral effects.
Indirect fire threats from RPG’s and rockets were also considered. Façade and primary structural element localized damage was determined using the Concrete Hard Target Spall and Breach Model, ConWep and SBEDS.
Based on the findings of these analyses we prepared both conceptual and design level options and drawings for cost effective retrofits that would significantly enhance the level of protection and reduce the vulnerability for facilities and staff at this compound.