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2016WinterShotcreteEMag

(a) (b) Fig. 2(a) and (b): Large dome shotcrete installation plete the large dome. The reinforcement wiring for these domes was extremely difficult due to the geometry. Surveyors established the correct geometry, but as each section was completed, there was less area to walk on and increased chances of the wires being damaged. There were numerous evenings when the contractor’s or owner’s representative, who wanted to visualize what the domes were going to look like, had to be chased off of the domes to prevent damaging the layout (refer to Fig. 3). One of the challenges for the shotcrete placement was creating an accurate dome shape. After the shotcrete work was complete, a fluid waterproofing membrane was applied directly on the concrete surface. This required all of the shotcrete surface to be finished on the curved surface within tight construction tolerances. Any deviation in shape would have been very noticeable. Furthermore, any patching would have shown through the waterproofing membrane. A distinct advantage with shotcrete was the final shape could be continuously checked and adjusted as needed to make sure the proper geometry was achieved. This was extremely challenging in the large dome, first with it being such a large structure and then having to install it in six different sections, where the final structure could not be visualized until all six sections were complete. This challenging placement was successfully executed by Dees-Hennessey with no issues or patching required. In the end, the owner was very satisfied with the shotcrete surface texture and geometry. Additionally, they were able to use a thinner and simpler waterproofing membrane because of the quality of the shotcrete Fig. 3: Large dome shotcrete preparation Fig. 4: Medium dome with channel Shotcrete • Winter 2016 19


2016WinterShotcreteEMag
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