Business and Professional Practices
Full Session with Abstracts
In a world where data is collected in nearly every aspect of our lives in the built environment, there is surprisingly little feedback regarding how well newly constructed and existing building perform compared to their design requirements. Current building codes require a minimum level of stiffness and strength, distributed properly, to assure performance. Yet, the industry as a whole is resistant to measuring the performance of structures. This sort of feedback is essential to assure the existing building stock is healthy, and that for new designs, the design intent was met. As we continue to experience larger storms and natural events, tracking degradation is critical to understand the Risk Profile of structures to assure safety. Therefore measuring their performance to identify high risk structures is consistent with good engineering practice and it is integral to community resilience and public safety.
Recently, improvements in technology and assessment techniques have made it practicable to assess the structure itself, and add a new capability to assessing structural performance. In a few hours, an assessment from very small dynamic movements can be processed into a structures Dynamic Signature and yield a risk profile of the building. With cloud computing, this assessment is made in near real time after data is collected.
Using accelerometers that are extremely sensitive, it is possible to use low amplitude excitation from natural sources (such as wind or traffic) to obtain information about the in service performance of the structure, from an analysis of tiny movements in a process that is analogous to the use of an electrocardiogram to judge the state of health of a human. The measured tiny movements reflect the movements of the structure even up to very large motion, and give a direct measure of the capacity of the structure, and the presence of any anomalies or weaknesses and their location. The techniques and analysis have been used on buildings in the USA, Australia, New Zealand and other countries to support decisions about the viability of continuing to use a building, what repairs/ improvements need to be made, and even whether construction work is safe to continue.
This technological advancement will provide a tool to proactively and objectively assure performance to validate building capacity. This will provide the needed feedback to improve the design process, assure that buildings are safe, avoid damage to adjacent buildings and allow re-occupancy after natural events. Examples will be given in the presentation.
1) Assessment of a building that was damaged by an earthquake. Objective measurements were used to identify the high risk profile which was inconsistent with traditional inspection techniques. The objective measurements identified the fundamental structural weaknesses and located damage.
2) Real-time dynamic assessment used to quantify the performance before and after a large damaging event.
3) Assessment of a school which was being upgraded to more modern standards. Dynamic measurements uncovered a geotechnical weakness which drove the implementation of geotechnical stabilization.
4) Real-time measurements that helped identify damage that went undetected. The unique approach was used during blasting and resulted in changing the means and methods to stop further damage to an iconic structure.