SCAFFOLDING COLLAPSE
Areas of expertise include structural engineering, subrogation
Scenario
An 11-story multifamily residential building in south Florida was undergoing construction of a 3rd level swimming pool deck. During the scheduled concrete placement, the shoring failed and the scaffolding collapsed.
The building is constructed of cast-in-place concrete columns, concrete beams, concrete stairways, concrete floor, and a deep foundation system with a structural concrete slab at grade elevation. The exterior walls consist of concrete masonry unit (CMU) blocks and storefront system.
ProNet Group was retained on behalf of the property development company to evaluate and determine the origin and cause of the shoring collapse during concrete placement.
Additional Information
Inspection of the area where the collapse occurred revealed the following:
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Collapsed shoring and portions of reinforcing steel, with partially poured concrete members at the third floor level between gridlines 11-13 and gridlines D-P.
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Primary area of failure located between gridlines 11-12 and gridlines H-M.
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Tower shoring with stickers of shoring manufacturer.
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Typical tower shoring with diagonal bracings on two sides of the towers only.
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Tower shoring surrounding the failed area typically buckled parallel to the sides with missing diagonal bracings.
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Scattered 2x4 wood members used to brace/connect individual towers.
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Typical vertical standards pulled at the joints of the buckled tower shoring.
Outcome
ProNet’s team was able to determine the collapse of the shoring system during the concrete pour resulted from omission of the diagonal bracings on two sides of the tower shoring, and the shoring system was installed in violation of the shoring manufacturer’s guidelines and basic engineering principals.
Additionally, close inspection of the failed areas and review of the shoring calculations revealed no areas of excessive loading applied to the shoring system.
