SK&A’s Repair & Restoration Group provided concrete repair services for a corrections facility located at 1901 E Street, SE. After reviewing the original precast design drawings dated September 1990 and observation of the existing conditions, we identified the deterioration of two precast panels located above the gymnasium that cover the satellite kitchens on the eastern portion of the facility. Both panels showed signs of movement.
During our investigation, the roofing material and isolated concrete masonry unit (CMU) blocks were removed, uncovering the existing conditions of the connections. The precast panel connections had failed and the horizontal steel plate (which extends from the concrete slab) was bent downward. The intermediate level connections were specified to be connected to the concrete slab, similar to the roof level. The panels have three different elevation locations with rigid connections: at the gym roof, the satellite kitchen floor, and the roof level. After numerous expansion and contraction cycles due to weather, the welds likely reached the point of fatigue and broke, due to the lack of vertical expansion relief.
Our recommendations for pulling the two panels back into their original position included:
The new and repaired connection points would accommodate vertical displacement between the precast panel and the concrete slabs by installing bolts with vertical slotted holes in the connection plates and precast. The two gravity connections at each panel would not need to be reconnected.
We also recommended installing new gravity connections at the midpoint of each panel at the steel beam level and installing new connections at the midpoints of the panels, to introduce additional redundancy within the system and as a protection from any unforeseen internal damage to the precast panels, embedded plates, and remaining welds that may exist. All of our recommendations were implemented and completed.