A large awning on James Street, Burleigh Heads, collapsed leaving one man dead and several injured. Police question witnesses. Picture: Kit De Guymer - Courier Mail online picture source
This tragic awning failure claimed the life of a local developer Chis Walton and injured 5 others just near Christmas on the 23rd of December 2012.
Shop awnings are typically supported with cantilevering beams projected out from the adjacent shop building. Other common awning support systems will rely on steel tie rods connected higher up on the shop's external wall to support a projected awning structure above the footpath.
In this case it would appear that two primary cantilevered concrete block masonry beams have been provided for awing support. Awing roof and ceiling cladding has been simply connected to minor spanning beams between a main large steel beam located at the street side external edge.
Photos indicate some surface portions of the concrete blocks have become dislodged from the ends of the cantilevered block masonry beams. Some corrosion of the steel beam supports is also visible with only two or three minor bolt fixing present. It is clear this connection has failed.
This failure is likely to be the result of a combination of factors. Fixture corrosion may have reduced the available bolt shank section capacity. Rusting bolts may have also added expansive forces at the sites of these fixings into the face of the brittle concrete block units. Once this expansive rust force can cause the surrounding concrete masonry face to crack failure may be expected.
Shallow bolt fixings which may be only 100-150mm deep into concrete block masonry near a base "free-edge" is not a durable arrangement in a near surf beach environment or elsewhere.
To work reliably the bolt fixing would have been better placed using stainless steel bolts and offsetting the bolts with a larger fixing plate well away from the concrete masonry's free base and side edges. This would allow for some overlap in fixture locations with the steel reinforcement placed within the block wall cantilever. Face fixing needs to be confined by reinforcement given masonry's brittle non-ductile nature. Design capacities offered by bolt fixture design guides so close to the masonry free edges would not be expected to be sufficient.
Workplace Health and Safety Queensland - Recent awning failure findings
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