Construction of the most complex bridge under taken by Civilbuild was built for Xstrata at their Liddell coal mine to carry massive coal trucks, excavators and other heavy machinery over the main northern railway line.
The position of the bridge and its design posed project engineer David Tolmie and his team with innumerable challenges. The three span bridge is 60 metres long, 34 metres wide and designed to carry the weight of an 850 tonne excavator. It consists of 56 girders, 18 super T girders and jersey parapet kerbs each 1.9 metres high to absorb the impact load. All these components were built at Civilbuild’s pre-cast yard at Redhead.
The bridge is held in place by dead man anchors and 14 tie rod ends, stretched to 50 tonnes each. The majority of traffic using the bridge is large dump trucks, each weighing 50 tonnes when fully laden. The worst case scenario put to the engineers was a situation where the bridge was covered end to end with fully loaded coal trucks.
The bridge has been designed and built to withstand those pressures plus the vibration forces from mine blasting nearby and that has required additional features not normally found in a bridge.