STRUCTURAL RISK ASSESSMENT AND OPTIMIZED  OF AN INSTITUTIONAL BUILDING

The principals conducted risk assessment and upgrades of a deficient truss system supporting seven story’s and the roof of a Municipal Building. The truss joints were under-designed and more than 60% of the complete penetration welds contained inclusions. The risk assessment was conducted using Reliability-Based methods and extensive FE simulation of the full trusses. The required upgrades were to achieve the code target reliability index and prove equivalence to the required safety under “Alternate Methods” as prescribed by the Alberta Building Code. The FE simulation results were validated with actual field-measurements of joint deformations along with extensive monitoring with strain gauges. The Reliability Index of the structure was calculated and compared with the NBC 2015 code requirements. The client took necessary actions to secure the occupants upon the recommendation of the risk analysis. Under real time monitoring of actual load against predicted, loads were relaxed on the truss systems, repairs to joints were completed and reloading applied. A detailed FE collapse model was developed early to estimate the footprint of debris in the remote event of truss failure. Occupancy was restored to the affected portion of the building.