TWM Contributor: Thomas Packman, PE, SE Structural Facilities Practice Lead

A Snapshot of Structural Health

The First Line of Defense for Building & Facility Owners
All facilities deteriorate over time; weather, salt, and general wear and tear translate to rust, spalls, cracks, and potential loss of capacity. The condition of a structure can be impacted by many different factors, which might not be directly related. Examples of deficiencies that could be uncovered during a condition assessment, or events that may trigger the need for a condition assessment include:

  • Undetected Leaks | Leaks can expose wood or metal structures to moisture resulting in rot and rust.
  • Undocumented Modifications | Changes made during renovations can compromise the integrity of a structural system and lead to confusion or errors during future planned work.
  • Vehicle Collisions | Collisions impart significant forces that are typically not considered in the design process and can compromise a structure’s stability, resulting in potentially unsafe conditions. Uncertainty around the effects of a vehicle impact can leave owners unclear about how and where they can safely continue to use a facility.

Assessing Structures
When a facility owner or user suspects damage or a structural defect, it’s better to make the decision to start an investigation rather than wait and potentially let an issue fester.

A structural condition assessment is a tool that can be used as part of a multi-phase investigation and design project. A licensed Structural Engineer will observe an existing structure, identify apparent damage or deficiencies, and provide recommendations for future repairs or additional investigation. This information is summarized in a report that is presented to the owner for aiding in future planning and funding decisions.

ASCE 11-99 Guideline for Structural Condition Assessments of Existing Buildings is an industry standard reference that is used to help develop the scope of assessment. TWM’s team of structural engineers conducts structural condition assessments that are tailored to fit the needs of our clients, whether it’s a quick and relatively short “Preliminary Investigation” or a more involved, in-depth “Detailed Assessment”.

Preliminary Assessment
Most of the structural condition assessments that TWM performs start out as Preliminary Assessments. Prior to the investigation, TWM’s structural staff will review available documents, including existing or as-built plans and specifications, reports from previous condition assessments or inspections, and client photos and observations. Existing documentation can help the team focus their observations on critical items and reduce the time and effort required to complete a preliminary assessment.

During the investigation, staff performing the assessment focus on qualitative observations by identifying apparent deficiencies or damage and documenting the general locations of suspect conditions. The observations are summarized in a report that includes documentation of the observations and recommendations for future work or investigation when applicable. The work included in a Preliminary Assessment can be carried forward into a Detailed Assessment, if the observations warrant additional investigation. Frequently a preliminary assessment is sufficient to recommend future design / repair work or determine that the observed structural defects do not need to be repaired.

Detailed Assessment
A detailed assessment may be recommended for several reasons:

  • Inconclusive Results | The results of the preliminary evaluation are inconclusive.
  • Complex Issues | The deficiencies or deterioration are of a nature that a greater level of analysis or consideration will impact the recommendations.
  • Code Requirements | An observed condition or planned alteration triggers a building code requirement for additional analysis or evaluation.

Generally, a detailed assessment includes each of the components from the preliminary assessment but may also include quantitative evaluation, including field measurements of existing structural member sizes, analysis of a representative number of structural elements, and evaluation of special loading conditions. Less commonly, TWM may engage a material testing consultant and establish a material testing program for structural members. We recommend this where material strengths can’t be determined from the available documentation or where presumptive values from the construction era can’t be used.

The results of a Detailed Assessment will typically be provided in a report format similar to a Preliminary Investigation or Assessment. However, the Detailed Assessment report will describe the methodology of measuring and analyzing components, and the recommendations will be based on a more sophisticated evaluation.

Achieving A Technological Advantage with LiDAR
TWM’s geospatial services often go hand-in-hand with our structural assessments. Depending on the particular conditions of a facility, we may recommend collecting a high-resolution point cloud using our LiDAR scanning technology. Scanning a facility is particularly useful in instances where existing facility drawings are incomplete or unavailable. This data can be collected quickly, reducing the field time required to complete the evaluation. A quality point cloud can give TWM’s structural staff a better understanding of the visible portions of a structure and can be used to jump start preparation of any necessary repair drawings after the assessment is completed.

Beyond Evaluation: Turning Insights into Future Design
Regardless of whether a preliminary or detailed assessment is completed, the report will often include recommendations for future design or repair. The recommendations should be specific actions that the owner can take going forward. At this stage, our team can discuss with the owner the options available to address and correct the observed damage or deficiencies. Our structural engineers can review potential repair solutions, budget considerations, and the considerations for phasing or staging future work to minimize disruption to the building’s operations. With a clear understanding of the issues and the owners’ constraints, TWM can provide the owner with a scope and fee proposal to complete the design work.

Protecting Your Investment
Similar to medical well visits, structural condition assessments are an opportunity to identify issues early, before they cause significant damage to the “health” of a building. Structural issues that go undetected may become more expensive to repair and may present a greater safety risk, the same way undiagnosed ailments can result in significant healthcare costs if not identified and treated early.

We’re not recommending a yearly assessment for every building, but if you notice a change in the structural system of the building that concerns you, it’s prudent to get the opinion of a licensed structural engineer. Assessments allow for an engineer to understand the scope of the problem, provide more accurate fee estimates for repairs, and hopefully reduce the risk of discovering unforeseen conditions during future design or construction.

If you have concerns about a commercial, industrial, or institutional building structure, reach out to TWM to discover how we can help.

Read more about TWM’s structural engineering services.