Structural stability is not guaranteed for the lifetime of a building and a property condition assessment. Effects of aging, corrosion, poor construction, and repeat shock events are all factors that can cause degradation and affect the overall stability of the structure. Visual commercial building inspections only point out obvious defects. But a Dynamic Signature Assessment objectively measures the performance of the structure to determine the stability and to quantify hidden risks while providing a building inspection report.
Structures can, and do fail which is why you need a sophisticated property condition assessment to give you a correct building inspection report. What matters is the magnitude of the failure. A failure can be catastrophic with a total collapse, or to some moderate level possibly making them unsafe for occupancy. It is the goal of the designer to prevent catastrophic damage under severe events (hurricanes, earthquakes etc.). Understanding how vulnerable a structure is to a large event is important for all parties. A Dynamic Signature Assessment allows for a prediction of the level of damage to expect from the shock event to which the building was designed.
Building Codes are widely regarded as being an absolute measure of safe design. They are not. This is caused by the fact that they are based on a risk that is acceptable to a local society. Societal acceptance changes with time, and structures can degrade with accumulated damage. Unfortunately, there is almost no feedback method regarding the actual performance of new and existing structures. This leaves decision makers with the unenviable task of making decisions with little useful information.
In our database of over 800 measured buildings (graph to the right), each dot represents a building measured with a Dynamic Signature Assessment. The Risk Ratio is an index which tells how closely a building performs compared to code requirements. A value of 1 means the building is at code levels. Those to the left of the 1 value perform below the required level. Our database shows about 10% of structures are well below requirements. This poses a hidden risk to society which continues to be ignored until a shock event occurs. Then excessive damage and sometimes collapse is a result. Weak structures can now be identified.
A Dynamic Signature Assessment is a one-day measurement that will memorialize a structure’s performance, quantify its structural risk profile, and can be used to identify weaknesses or problems. It’s used to help prioritize budgets, validate construction work and assess damage after a wind or seismic event. This method adds a level of confidence in the decision making process that the traditional methods of analysis cannot match.
This advanced approach represents a paradigm shift in understanding structural performance. It helps identify structural risk for all stake holders and is needed for community resilience and public safety.
To learn more about this advanced approach, download our Structural Commissioning White Paper by filling in the form below:
Q: Why is it valuable?
A: Codes require a certain level of capacity. Measurements must be taken to validate that the structure has the required capacity. Also to ensure older buildings still retain their capacity.
Q: What is Structural Commissioning?
A: It is an accurate measurement of the dynamic parameters of the whole body movements of a structure.
Q: What does the analysis tell me?
A: It provides a precise measure of the lateral load bearing capacity of the structure. It verifies that the structure meets the design intent relating to dynamic characteristics identified in the codes. Also, it can identify weaknesses, if they exist.
Q: How long does it take?
A: From 2 to 8 hours, depending on building geometry.
Q: How are measurement taken?
A: Sensors are placed at various locations around the structure to get it’s movements. It is non-invasive and can occur without disrupting works or occupants.
Q: Why haven’t people done it in the past?
A: The research community did these measurements to help establish the code requirements, but it was prohibitively expensive and difficult to accomplish in the past.
Q: Why is structural commissioning necessary?
A: ASCE 7-16 now has performance metrics as part of the design requirements. It also references the methods to use to take the measurements. It is an important validation step for any structure to prove it was built as required.
Q: How is it accomplished?
A: Professionals trained in taking dynamic measurements are sent to each site with the correct equipment. Measurements are taken at specific locations for a preset duration and sent back to the experts for analysis. The experts should be companies with a proven track record of having the skill set of advanced structural dynamics, and have performed the analysis in the past.
Q: Does Structural Commissioning verify that every part of the structure is compliant?
A: No. It give an accurate assessment of the overall holistic building performance. Additional measurements or testing for specific elements can be used to validate portions of the buildings such as floor vibrations and other performance aspects.
Q: Is it expensive?
A: The technologies that we have today allow for these measurements to be taken quickly and at a cost-effective matter. The costs are well within reason based on efficiencies created with advanced technology.
Q: What companies have used Structural Commissioning and why?
A: It provides value to various types of customers who are responsible for the quality and safety of structures.
Structural Commissioning is a performance test which acts as a ‘health check’ for commercial building inspection. All responsible parties benefit from knowing the real behavior of each structure.