Innovation In Roads (2011)



Every year, across the breadth and with
the New South Wales, the RTA undertakes projects from the simple to the simply amazing. With over 17,000 kilometers of transport
infrastructure under our management, we are continually looking for ways to maintain and construct our network. Our engineers and designers seek out new and improved solutions for the construction challenges we face. We win awards for both the technologies we develop and the roads we construct. What you are about to see is a showcase of some of the projects that illustrate the calibre of our innovation. They also demonstrate the high performance culture within the organisation. Voiceover: Continuous Flight Auger Piling,
or as we call it, CFA piling is an important innovation. It was used by the RTA on the upgrade of the Hume Highway at Tarcutta. Piling is used to construct deep secure foundations for
structures like bridges. The RTA was able to complete piling work on the Tarcutta Creek bridge faster than if traditional piling techniques were used. We will explain what this new piling technique is and how it works. Jonathan: CFA Piling, or Continuous Flight Auger Piling, is essentially a four-stage process. Drilling the hole, injecting the concrete, withdrawing the drill and reinforcing the structure. Firstly, a continuous Flight Auger is drilled into the ground to the required depth. Continuous Flight simply means that the cutting surfaces extend for the full length of the shaft, much like a typical drill bit you find in a hardware store. Then as the auger itself is removed, concrete is injected down through the hollow shaft of the auger itself, filling the hole up as we go. After that it's just a matter of inserting the reinforcement cage down through the concrete. This CFA Piling technique is not new, however to date, it has had limited use within the RTA. One of the big benefits of the CFA process is, that the walls are always supported. First by the auger, and then by concrete in the hole, and there is no requirement for casing or drilling fluid just like you'd have in conventional bored piles. This all helps make it a quicker and more economic process. It's twice as fast as traditional methods, also it's almost vibration free and only creates low levels of noise, which is important for those working with the system and for surrounding residents. Voiceover: In summary CFA piling was used by the RTA at Tarcutta. It cost less than traditional piling methods. It was notionaly twice as fast as traditional piling methods. It was almost vibration free and only created low levels of noise. This was important for project workers and especially for the surrounding residents. Sydney's Inner West Busway project saw the RTA introduce a brand new road technology into Australia. This technology is called the quick change movable barrier system. You will see how this system works, and you will see the end result which is the creation each day of a dedicated city bound bus lane in the morning without affecting the overall flow of traffic. Andrew: The challenge of giving priority to
public transport is one that anyone sitting on a bus in the Sydney metropolitan area will be aware of. The movable barrier system is a system that meets that challenge. Moving the road lane barriers let's us make the most of our road space. While it has been used successfully overseas, the Inner West Busway project in Sydney is the first time we've seen it here in Australia. The road lane barrier is a continuous series of one metre long concrete barriers weighing almost 700 kilograms each. They are connected to each other by steel pins to form a continuous wall. A special vehicle moves the link barriers from one lane to the next to change the traffic configuration. This will create a bus lane in the morning peak. A T-Shape on the top of the barrier allows a special vehicle known as the "zipper" to pick it up as it travels along the road and to put it back down on the other side of the lane. It does this at speeds up to 16 km/h, this gives us a relatively quick, flexible and safe solution to improving the efficiency and reliability of peak hour bus services within a very narrow and busy transport corridor. Voiceover: In summary, the movable barrier system used by the RTA on the Inner West Busway is the first of it's kind in Australia. It is a barrier transfer machine to transfer concrete barriers from one side of the lane to the other. This creates a dedicated city bound bus lane in the weekday morning peak traffic periods, when there is less traffic travelling in the opposite direction. It improves bus travel times and reliability on Victoria Road which carries two hundred thousand bus passengers each week. Voiceover: The Hunter Expressway project presented many engineering challenges for the RTA. One challenge was the existence of underground voids or large empty spaces. These voids have been created by past mining activities. Before this project could proceed the RTA
had to develop a special technique to fix some voids. This project runs through an area rich in Aboriginal heritage and natural beauty. So the RTA had to construct a project, that did not interfere with the area's culture and environment. Let's see how. Peter: In New South Wales, in the Hunter region, the RTA is building the forty kilometre Hunter Expressway from the
Newcastle interchange on the F3 freeway to Branxton on the New England Highway. There are many engineering challenges in this project. Extensive mining has left the large voids under the ground. We need to overcome the challenge of the voids by identifying the location and depth and developing a strategy to fill them. Mine voids in the top fifteen metres, of the
soil, are generally excavated, collapsed and replaced with compacted soil. Voids deeper than the fifteen metres are filled with grout injected into pre drilled bore holes. Another challenge is the construction of of approximately 800 meters of high bridges called via ducts through the Sugarloaf Range. These three sets of twin bridge structures will be Thirty Four (34), Thirty Seven (37) and Forty Two (42) meters high. Long span bridges help reduce the vegetation footprint and minimize the impact on Aboriginal heritage at mid Myall Creek.
Our design also provides fauna connectivity so animals can travel freely back and forth under the bridges. The mine voids beneath the bridge will be treated. However, the foundations of the bridge structure also have to compensate for other large-scale movements. Three sets of twin balanced cantilever bridges will span the steep gullys of Sugarloaf range. The bridge construction technique relies
on building the vertical piers first, from the top of each pier a box girder reaches out to join up with its neighbouring piers in both directions cantilevering out one section at a time. The techniques employed are for a good balance of cost, whilst minimizing environmental impact and providing good strength and durability. Voiceover: In summary the RTA's treatment of the undergound mine spaces and the construction techniques used on the Hunter Expressway, minimise the impact of the construction on the Hunter region's natural and cultural environment, provided an end product that is strong and durable, offered a cost-effective solution. Voiceover: Diamond Grinding is a new technology used by the RTA, to resurface concrete roads. The RTA now uses Diamond Grinding to maintain roads across New South Wales. As you will see, Diamond Grinding results in a road surface that is consistent and level. This means a smoother road and a more comfortable journey for us all. Peter: Diamond Grinding is a resurfacing or rehabilitation technology. It delivers marked improvement in ride and comfort over traditional methods. In it's crudest form, the Diamond Grinder works like a long door plane. It removes surface irregularities caused during construction and through repeated traffic loading over time. Diamond Grinding involves removing a thin layer at the surface of the pavement. It does this by using closely spaced diamond saw blades. By running the blade assembly at a pre-determined level it produces consistent depth saw cut grooves. The uncut concrete between each saw cut breaks off at a more or less consistent level This process leaves a consistent and level surface. The result is a pavement that is smooth, safe and quiet with an improved ride. Voiceover: In summary, Diamond Grinding used by the RTA removes Road surface irregularities caused by construction work, or lots of traffic, creating grooves. Produces a level road surface. Results in a road that is smooth, safer and quieter. Voiceover: The RTA had a problem with deep water logged soils on the Far North Coast of New South Wales, we decided to use new technologies to join soft soils on the Pacific Highway upgrade at Ballina. Vacuum consolidation and other techniques are a unique way to treat very deep soft soils prior to building a road and we'll see how the RTA has prepared the soil ready for construction. By using vacuum consolidation and other techniques, the Ballina Bypass will be delivered much earlier than if traditional road building methods were used. Delivering a faster Pacific Highway upgrade benefits drivers in Ballina and across the state. Bob: The underlying soft soils on the flood plains in Ballina have been a major challenge for the RTA and building a new by-passing of the town. We used a range of methods to remove as
much of the air and water as we could before we build the new road. One such method is Vacuum Consolidation. A brand new technology for Australia. This technique involves, placing new embankment over the soft soils, inserting special pipes into the
soft soils and new embankment and then connecting those pipes to large vacuum
pumps. Wrapping the new embankment with a heavy airtight membrane and using the
pumps to suck out the air and water. The water is sent to holding ponds for treatment prior to discharging in to local waterways. While this technique is more expensive than other methods it is much faster and allows the RTA to
build the road much more quickly. We were able to use this method on a time
critical section of the project and achieved settlements of around five metres over nine months, which would have taken us many years using a more conventional technique. Voiceover: Vacuum consolidation and other techniques used by the RTA on the Ballina Bypass produced excellent results. In summary: It's a relatively new technology in Australia. It saved time and money when compared to other techniques. It resulted in the soil consolidating and forming a stable foundation for the construction of the Pacific Highway. Ann: Just a few examples of how the RTA is at the forefront of innovation, in the way we work and the technologies we use.

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