Bridge traffic rolls smoothly on as roadway is raised for Lane Cove Tunnel project

Traffic continued to roll smoothly over one of Sydneys busiest bridges recently as the roadway was lifted under their wheels to accommodate an exit to the new Lane Cove Tunnel. Engineers employed by Thiess John Holland employed compact and powerful high-pressure (700 bar, 10,000psi) Enerpac hydraulics from Coates Hire Industrial Service to precisely lift a bridge on Lane Cove Road to replace piers obstructing the tunnel exit near Mowbray Road. The lifting technology involved - including a series of extremely low height CLP Series Pancake Lock Nut Cylinders is applicable to a broad range of bridge, road and tunnel infrastructure involved in civil works, resource developments and major construction projects. Project Engineer, Civil, Pacific Highway, Mr Michael Damo said three existing bridge piers - installed well before the $1billion-plus project was conceived - had to be removed from the path of a dual carriageway exiting from the 3.4 km twin, two / three lane tunnel under Epping Road and Stringybark Creek. The tunnel, linking the M2 Motorway and the Gore Hill Freeway, will cut an estimated 15 minutes off a trip to the city. To ensure minimum traffic disruption while replacing the old piers (Lane Cove Road is used by thousands of cars and trucks daily) Thiess John Holland had to pour the six new pillars under tight overhead room beneath the existing bridge then jack up the bridge to remove its old rubber bearings and replace then with new bearings on the new pillars. The bridge, spanning about 20 metres, was raised just 6mm by a series of mechanically synchronized 250-tonne Pancake jacks positioned on top of the old piers adjacent to their elastomeric pot bearings. Coates Hire Industrial Services Colin Chapman says the main issue to be addressed was the confined space the lift did not require the sophistication of the latest PLC-controlled Enerpac Synchronous Lifting equipment (also used on bridge lifts) because of the relatively straightforward nature of the job once the Pancake jacks had been installed and traffic flows controlled to facilitate the lift. The 260-tonne CLP 2502s we used have plenty of stroke for jobs such as this they go up to 45mm fully extended but they are only 159mm high with their plungers retracted. With lock nuts for mechanical load holding, they are very safe and very simple to use. The beauty of the equipment from the clients point of view was that they could hire the specialist low-profile equipment needed for this single application then return it after the job was completed. Mr Damo said that once the Pancake jacks had been positioned along the old piers running down the centre of the bridge, it was relatively straightforward job to synchronise them through one manifold to ensure an even lift. The synchronised lift of the centre of the bridge was handled from just one pump feeding all six jacks, so they moved in unison. Traffic continued to use the bridge while the work was progressing - We had to change some traffic management, said Mr Damo. We had to reduce speed on the bridge, the amount of traffic and the weight of vehicles while parts of the job proceeded, but it was not a major long-term disruption. It was a very smooth job using techniques that have been widely proven. The Lane Cove Tunnel, expected to be completed in 2007, is a key link in Sydneys orbital motorway network connecting the Gore Hill Freeway at Artarmon with the M2 at East Ryde. Motorists travelling between Falcon Street and the M2 will bypass 26 sets of traffic lights.