The Importance of Site Visits For Blast Vulnerability Assessments

When writing an RFP for a Blast Vulnerability Assessment there are a number of things to consider, one of which is whether to pay for the engineers of the assessment team to visit the site in person.  Often, the inclination may be to reduce the cost of the assessment by excluding a site visit.

We do not recommend this approach, as it limits the ability of the assessment team to develop feasible, effective solutions tailored to the requirements of the specific buildings and compounds.

No matter how much information may be available about the buildings and structures, it is rarely as much as is thought and it is no substitute for the engineer-assessors seeing the building and compound for themselves.

Typical Site Visits

Site visits will vary based on the previously available information, the number and complexity of the buildings, the threat-types to be assessed, and the location of the project.    At a minimum, the following should be included:

• Meeting with the Security Staff to identify security concerns, critical areas of the compound, local risks associated with the everyday function of the compound, etc.
• Meeting with the Operational and Maintenance Staff to identify limitations on modifications to the building and compound.  Limitations could include a need to maintain operability of windows, size of trucks requiring entry to the compound, etc.
• Visual evaluation of the compound configuration and surrounding area to evaluate possible non-hardening measures which can be easily implemented to provide protection to building occupants (increase standoff distance, layout and entrance orientation to minimize speed of vehicular approach, etc.)
• Visual evaluation and non-destructive Investigation of the existing structures under consideration and comparison with existing drawings to validate the information required to perform the blast vulnerability assessment of the existing structures.
• Review of the local construction environment in order to understand local contractor skill sets, material availabilities and typical construction approaches.

Destructive Investigation

When there is limited information available regarding the existing building construction and configuration, or when the validity of the information may be suspect (i.e. in countries where there is no established building code and inspection process), destructive testing and investigation may be advisable.    This testing could include:

• Cutting and removing physical samples of concrete, masonry or steel elements of the building for testing by a laboratory.
• Using electronic meters to map reinforcing locations and patterns in masonry and concrete structures.
• Selective removal of concrete or masonry to determine the size of reinforcing bars.
• Removal of architectural finishes to inspect connections between structural members.