Geotech Survey Works in PNG
Hegigio Gorge Pipeline Bridge is located across the 500m deep Hegigio Gorge in the PNG Southern Highlands. Due to the complexity of the bridge, the remote location and the limited access around the
abutments, innovative and unique design solutions were required to allow for the construction of the bridge.
The bridge comprises three catenary cables; two horizontal and one vertical joined together by a series of wire stays and cross beams. Two parallel runway beams connect the series of cross beams together, which allow access along the bridge via a trolley. The main cable is connected to a 33m high A-frame tower at the southern abutment and a 4m high tower at the northern abutment.
On 26 February 2018 a large earthquake (magnitude 7.5, focal depth 35km) struck the PNG Southern Highlands with its epicentre in the Nipa-Kutubu district, some 40km west of the bridge site. The earthquake caused some damage to the Hegigio Gorge Pipeline Bridge.
A stability assessment was conducted and involved an inspection of the upper face of the southern abutment using abseil techniques to document the level at which bedrock appears in the portion of the south abutment slope below the tower.
Bells was contracted to assist in a geotechnical survey of the Bridge Abutment.
The works involved the provision of rope access for three proposed traverses each approximately 50m below the bridge footing. Rope access anchoring into the backslope cutting of the well pad and the opportunity to anchor off the bridge footings.
