Author: C. Blackett-Ord (CARE + Blackett-Ord Conservation Limited)
4 January 2016
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C. Blackett-Ord (CARE + Blackett-Ord Conservation Limited)
This short article describes the rehabilitation of an office building in Baghdad damaged by a missile strike during the 2003 Iraq War. The author briefly sets out the damage to the building’s steel frame, explains how a structural model was created to enable the design of a supporting steel frame, and describes the installation of the temporary supporting frame and new steel columns using hydraulic jacks to raise the building’s upper stories.
A tuned damping solution was developed to mitigate walking induced vibration of joist-framed floors in 25 rectangular, trapezoidal and irregular-shaped rooms in an educational facility. The make-up of the floors was concrete on metal deck, supported by open-web steel bar joists. The floors came in various sizes (800–1200sq.ft) and shapes, with the first resonant frequencies in the 6.5–7.5Hz range. Following the measurement of vibration and finite element analysis of the floors, 50 tuned mass dampers (TMDs) (two for each room) were designed, manufactured and installed to effectively address the vibration challenges of the first structural modes of the floors they were designed for. After installation of the TMDs, the effectiveness of the tuned damping solution was evaluated via further measurements. TMDs effectively dampened the first structural modes of the floors in various rooms and lowered their walking-induced vibration to acceptable levels.
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