BGC Precast’s engineers, working in close collaboration with the design engineers, were able to arrive at a winning combination of over a thousand 17m spanning, 400mm deep hollowcore slab panels, supported by 238 precast beams. Edge panels and lift and stair cores comprised another 136 wall panels added to the project. Even the ramps were provided in hollowcore. The 17m span drastically reduces the number of support columns and increases the amenity of the car park by giving it a very open feel. The carpark once handed over, will be owned by PTA ( Perth Transport Authority).

It is no surprise therefore to discover that over the last 5 years, BGC precast have been involved in 13 tanks projects for this valued client. A typical tank comprises post tensioned stack cast wall panels, precast roof support columns and beams, the latter usually kerf connected and sleeved and dowelled into the columns for simplicity, and precast hollowcore slab panels.

The photos do not do justice to the degree of innovation provided by BGC precast’s in-house engineering team, who had to include differing top surface final finishes, (which by nature, varied between trafficable and non-trafficable balconies), cast in floor drains, and intermittent upstand beams. Utilising BGC Precast’s innovative self-levelling precast stair system, including internal staying of the core walls, meant once the hollowcore slab was placed the resultant absence of any propping or bracing meant fit-out from prepacked and delivered material stockpiles could commence immediately on the floor below. A massive saving in time for the builder which he diligently embraced. Other challenges overcome were tying-in of the hollowcore to the wall panels where wet area set downs precluded the application of topping. Extensive use of BGC Precast’s new lateral and bearing connections for hollowcore panels to the wall panels were employed, which naturally included wall panels supplied with cast-in hollowcore support corbels, resulting in even further time savings.

A further advantage, means that these panels being monolithic are not subject to cracking from daily thermal stresses since they invariably are subject to varying amounts of shading. They are also thermally and acoustically broken from the main slab; small and insignificant items to most except for BGC Precast’s discerning customers who appreciate this level of attention to detail where other suppliers may just continue the hollowcore out to the edge of the balconies, negating all the value-adding features listed herein.