From building bridges to supporting piers, precast concrete is critical to the success of many infrastructure projects, but few know the extensive logistical planning and coordination required to safely deliver these goliath-like structures to site.
For every colossal concrete structure, there is an equally awe-inspiring network of companies, teams and technical specialists that are needed to collaborate to bring the project together.
If anyone knows this, it’s concrete precast specialist NVC Precast. Having worked in the construction industry for over 30 years, the company specialises in manufacturing a range of reinforced and prestressed substructure and superstructure components for the civil construction projects. This includes concrete panels and piles, abutments, crossheads, pier columns, planks, T-Beams and L-Beams.
Pre-casting concrete components off-site provides many benefits to the to the overall construction process. By ensuring that the elements are cast in controlled conditions, the concrete quality is improved, allowing rapid on-site installation which reduces the overall construction footprint and duration of the works.
Transporting the precast elements that are continually increasing in dimensions, mass and complexity requires meticulously orchestrated planning, extensive approval processes and strict health and safety precautions, for both the operators and the road users.
Cindy Stocks, CEO of Stocks Oversize Pilots, has worked with NVC on some of these mammoth projects, providing pilot escorting service for many of the oversized beams and precast elements supplied by NVC Precast to large infrastructure projects throughout Victoria. She has had her pilot driver license for more than five years and notes the importance of a strong team in the complex transport of pre-cast structures.
“There is an amazing amount of trust placed in these operators first and foremost by each other, the companies they work for and represent, the project managers and the general public as a whole,” she tells Roads & Infrastructure. “Movement of products that are this big and the weights involved mean that those entrusted to operate this equipment must be at the top of their game each and every time they venture out on to the roads.”
Stocks sits down with Roads & Infrastructure to walk us through the journey NVC Precast, and the transport teams must undergo to move these oversized loads. She draws from a recent NVC Precast project which required the creation and transport of 30-metre ‘Super T’ concrete beams. The transport team that undertook this immense task was Big Hill Heavy Haulage, assisted by Stocks Oversize Pilots.
Before any beam is loaded onto a vehicle, both NVC Precast and the transport teams undertake an array of transport permit approvals and route planning.
“The process is a lengthy one with many steps needing to be followed before you can even apply for an Oversize Load permit,” says Stocks. “Especially when transporting long and heavy items like a Super T concrete bridge beam that is up to 35 metres long, weighing approximately 85 tonnes.”
The first stage in the planning is to carry out an in-depth route survey of the proposed course. This determines whether the proposed roads are suitable to travel, given load weight and width. The team must also inspect whether there is enough road space and connecting roads to divert and clear traffic. A swept-path analysis ensures that the specialist vehicles can manoeuvre through the bends and intersections of the nominated routes. The team also calculates the potential traffic delays and the impact to other road users, considering everything from traffic signals, light poles, street signs, powerlines, and even street furniture.
“When looking at a route survey, particularly with a load of this length alongside the width of the heavy haulage equipment being used to transport the load, it is an absolute must to be 100 per cent sure that the load can safely traverse through each turn, intersection and roundabout,” Stocks says.
The company then applies for a transport permit detailing the finalised route with the equipment and load dimensions to the National Heavy Vehicle Regulator (NHVR), Australia’s independent heavy vehicle regulator.
Once the permit is approved, NHVR sends special amendments such as traffic control measures and bridge slow-down signs to assist with safety precautions during the transport.
NVC Precast works closely with the client representatives, transport providers and pilots to coordinate the delivery within the client’s scheduled delivery requirements on site, ensuring that the product has met all the specifications for transport including concrete strength and curing time. Clear and effective communication is critical for the successful coordination of each delivery with site contacts and organisation working within strict regulations and deadlines.
And finally, once NVC Precast has got the green light, the transport teams can finally move the beams.
“For every load transported on this project, we had four pilot vehicles and one steerer,” Stocks says. “The pilot vehicles function as a warning system to the public, and alert pedestrians, oncoming traffic and motorists of the oversized load. “
Signs and warning lights are used to notify road users of the large, transported item. “Where possible, the pilots inform oncoming or overtaking vehicles by UHF radio of the load dimensions, location, direction of travel and other matters that may affect traffic,” Stocks says.
The pilots and steerers also provide rear and side view intel when the load impairs the truck driver’s line of sight.
“They work in tandem to assess and inform the driver of potential hazards and obstacles,” says Stocks.
This includes indicating load clearance from obstacles such as trees, and overhead infrastructure such as bridge railings. They may also limit the trucks speed and increase the strength of the load lashings as extra safety measures.
During transport to the site, the loads often must cross narrow bridges. The team halts traffic at both sides so that the trucks can pass through individually, averting any dangerous situations.
Given the size of these loads, it is of little surprise that transportation requires very specific machinery.
“Typically, ‘Super T’ concrete bridge beams within Australia are transported with the aid of a widening float or a platform trailer towed by the prime mover, with or without a dolly, depending upon both weight and length constraints,” says Stocks. “These are determined by the proposed travel route and any limitations as to the roads travelled.”
The front end of the bridge beam is typically chained to a bolster that is either on the float or platform. The back end is attached to a bookend bolster, which is then connected to a remotely operated steerable Jinker. A Jinker enables manoeuvring of the load from the back: a key part of the steerer’s job.
With the route consisting of many tight corners, turns and roundabouts along the way, the steerer’s job is most crucial.
The steerers assist the truck drivers by remotely controlling the back trailers, manoeuvring the load through tricky areas. This allows the truck driver to focus on steering the prime mover and platform or lead trailer.
“The steerer works in concert with the prime mover driver to safely negotiate these turns and obstacles while the pilots manage the traffic to allow for the load to complete its wide turn,” says Stocks. “It takes a great deal of confidence in each other’s abilities, and capabilities, to navigate these obstacles safely with both the driver and steerer constantly communicating about obstacles and positions to travel through and past these obstacles.”
With this gargantuan process just another day in the office for NVC Precast and the transportation teams, it is worth a moment of appreciation for what goes on behind the scenes, or should we say on the roads, to get these products safely to their destination.
“It would be quite a safe statement to say that without the certified pilots utilised on these movements, major infrastructure projects like these would be cost prohibitive and almost non-existent,” says Stocks. “The safety of the public would constantly be at much greater risk. Making the tight turns at intersections and through roundabouts would be impossible without them.”
This story originally appeared in the June 2021 edition of our magazine. To read the magazine, click here.