The invisible barrier facing workers in building Sydney Airport’s new motorway
Construction workers on the $2.6 billion motorway project faced a raft of hurdles, but one was more challenging than most.
The Sydney Gateway was regarded as a risky project because of factors such as industrial contamination and the flight ceiling for the airport.Credit: Dominic Lorrimer
Near the fence of Australia’s largest airport is an invisible barrier that cannot be penetrated. It was something workers building a $2.6 billion motorway to Sydney Airport’s domestic and international terminals had to be ultra-vigilant about, especially when lifting loads.
The flight ceiling – technically known as an “obstacle limitation surface” – has required many of the new Sydney Gateway motorway’s light poles to be much shorter than standard poles.
Those closest to the landing approach for the main north-south runway are just three metres high, less than a third of the height of a standard street light. Even so, the flight ceiling is only about 100 millimetres above the motorway’s light poles near the runway.
The final section of the Sydney Gateway is due to open on September 1.Credit: Dominic Lorrimer
It illustrates the raft of challenges workers have had to overcome over the past four years to build the toll-free motorway, the final stretch of which will open on September 1.
Motorists will save an average of up to 17 minutes using a new Sydney Gateway exit to the airport from the WestConnex junction at St Peters, instead of driving through local streets in Mascot.
Transport for NSW project director Tristan Frost said construction near the main runway was highly constrained because of the flight ceiling, requiring much work to be undertaken during the airport’s curfew from 11pm to 6am.
At other times, construction equipment had to be modified for work near the airport’s boundary fence during the day to ensure it was below the flight ceiling. “It’s an invisible ceiling. All the workers were always mindful because of the ceiling in case they lifted anything,” he said.
Light poles for the gateway motorway near Sydney Airport’s main north-south runway are only about three metres tall, less than a third the height of standard street lights.Credit: Dominic Lorrimer
The flight ceiling was one of many challenges that made the new motorway a “very risky project”. Other risks included heavy industrial contamination, a nearby rail line to Port Botany and a building on the old Tempe rubbish tip, which required 10,000 column piles to be rammed into the ground.
“It’s literally like a bridge in the sense that those piles are founded down to 20 to 25 metres,” Frost explained. “The landfill is soft ground, and it’s not strong enough to have normal pavement that’s just compacted earth.”
Like projects such as Sydney’s mega-metro rail lines, construction was severely disrupted by pandemic lockdowns and wet weather several years ago.
All up, the gateway comprises five kilometres of motorway and 19 bridge structures, including twin arch bridges which are wider than the Sydney Harbour Bridge at eight lanes.
The opening of the final stretch to traffic will test officials’ management of greater traffic flows from the St Peters junction to the airport’s terminals. The gateway has the capacity for more than 100,000 vehicles a day.
Officials want to avoid a repeat of the chaos that happened after the Rozelle interchange opened last November, and the project has been opened in stages to limit traffic disruption.
Sydney Gateway comprises about five kilometres of motorway and 19 bridge structures.Credit: Dominic Lorrimer
Sydney Airport operations general manager Greg Hay said staff were working to ensure the smooth opening of the final part of the motorway connection, doubling kerbside staff to 60 for two weeks during peak travel periods.
“We’ve made sure that within the precinct as well, we’ve got defined areas and response plans to make sure that if there is any build-up of traffic, we can manage that in real-time and keep the traffic flowing,” he said.
“Gateway is not just a new road. It’s a critical piece of infrastructure that is significantly going to enhance travel times around Sydney.”
WestConnex general manager Denise Kelly said there would be a “settling in period” for the new airport connection, and she urged motorists to use recently released animated drive-throughs to familiarise themselves with their routes.
The final stretch of a three-kilometre dedicated shared path for cyclists and pedestrians as part of the Gateway project is also due to open on Friday. It will extend the shared pathway to the domestic terminal and the eastern edge of the airport.
Rest areas on either side of a bridge over Alexandra Canal for the shared path will serve as sites for plane spotters near the main north-south runway. “You are really under the belly of the planes,” Bicycle NSW planner Sarah Bickford said.
Transport Minister Jo Haylen said the final kilometre of the shared pathway would provide alternative access to the domestic terminal.
“This is the missing bit that actually makes sure there are good connections to the airport. Every single day, 30,000 people work at [the airport], and we want them to have the choice to be able to walk and ride safely,” she said.
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