Taxi cranes, designed to be driven to the job site without any support vehicles, ready to perform most lifting jobs, are a vital part of many crane owners’ fleets. However, as regulators enforce strict axle load limits, sometimes as low as 9t per axle, many customers find themselves struggling to road cranes capable of doing the jobs they want.
Klaus Meissner is director of product integrity at Terex Cranes. Formerly, he was director of product development for the company’s mobile and crawler lines, so he knows the all terrain market both as a crane builder and a regulatory expert.
He explains that whereas once crane users faced a loose regulatory environment, today they need to pay careful attending to axle loads. Asked about conditions in the EU, he says, "Axle load regulations are really being enforced. There are more checks by police, and more automated weighing of vehicles. When people do travel beyond the 12th axle limit, they are punished according to the law and fined significant sums of money.
"In some countries, bridges are worn out. The steel in pre-stressed concrete is corroded, and the bridges can’t take the loadings. At the same time, traffic is much denser. Many thousands of bridges now have limitations.
"Our customers working in Cologne, on the Rhine, tell us that often they can’t cross any of the bridges in the city. So they either have to travel hundreds of kilometres between jobs, or set up subsidiaries in the other half of the city."
Andreas Cremer is product manager for Manitowoc’s all terrains in EMEA. He says, "A 12t per axle limit is predominant in Europe. There is also a tendency, on some routes, for a limit of 10t per axle. This is mainly on bridges. The money is not there to repair the bridges, so instead the authorities reduce the allowed axle loads. This has been the case for some time in Scandinavia, and particularly in Norway. So, you see more cranes sold with tag axles.
"That tendency for lower axle loads is now coming to Germany as well. We don’t see tag axles in Germany. But it is becoming more difficult for customers to get permits. These laws have been there many years, but in the last two or three years, they are being more strictly enforced. In the past, in Germany, customers could drive a little overweight. Now they can’t. So now, customers are asking for cranes that can get down to under 10t an axle.
"In Germany, you can get different permits: by day, or by year. If you can get down to 10t per axle, it is easier to get annual permits. These cover working across a region, rather than a specific route. To get down to 10t, you need to remove all the counterweight on the crane, and have a separate vehicle for the counterwieght, or a trailer that you can run with the crane."
Brits living large
While crane owners face harsh regulations and enforcement on the European mainland, in the UK conditions are somewhat easier. Geoffrey Marsh is managing director of Marsh Plant. He says, "UK axle loadings are considerably higher than on the European mainland. We get a far greater allowance: 16,500kg per axle for Category C. Under the UK’s Large Goods Vehicle (LGV) licences, old 25t truck cranes were category B, but almost all nowadays are Category C. That limits you to travel at 40mph, but allows for higher axle loads.
"Our technical director, Shaun Leinster, with Steve Cooke of Ainscough, was in the group that thumped this out with the Ministry of Transport to get this concession, known as the LGV Category C, special types general order.
"The term taxi crane is convenient, but is almost a misnomer in UK, because we’re allowed to run so much heavier. Because we run cranes heavier, transmission stresses and strains are higher, which some of the manufacturers don’t like. Custom and practice in Europe, for years, has been to take an extra support vehicle. We don’t have to in the UK."
The weight of the world
But continental Europe is not alone in facing strict enforcement of low axle weights. Holger Haber is Manitowoc’s product manager for all terrains in North America. He says, "In the US there are very few regions where the machines can drive with the boom over the front, with more or less 12t per axle. You can do this in the greater New York City area, and in Chicago. In all other regions, you have to road machines on boom dollys with two or three axles. The limit is basically 10t per axle, but it can be even less. In some states, it is as low as 20,000lbs per axle (9,000kg).
"In some states, we have to put forward different proposals, which the authorities either approve or don’t. But they don’t explain their decisions."
"Road regulations in the US are strictly enforced. On interstates and highways, there are weighing bridges that any vehicles from small trucks up, have to roll through. Usually they calculate gross vehicle weight. On longer vehicles, they weigh in axle groups, so if you overload a little, it can be very easy to run into difficulties, if the weight is not evenly distributed to 10t per axle: if one axle is loaded to 10.5t and one to 9.5t per axle. So customers try to remove more weight. On some cranes, its hard to have any reserve, so customers go for a bit less.
"In Canada, regulations vary according to the season: so in Alberta, when the ground is thawing, the allowed axle load is only 9t; but when it is frozen, customers are allowed up to 12t per axle."
Li Fook Seng is Manitowoc’s product manager for all terrains in Asia. In major markets there, it can sometimes be easier for crane owners. While some markets benefit from their historic links with Britain, others need to use special permits for all terrains. He says, "Other than China, the biggest market in Asia is in Singapore. In most British Commonwealth countries the allowed load is 12t per axle. In Singapore and Hong Kong, customers are allowed to increase the axle load to 15t, as long as the crane and tyre manufacturers produce the correct documentation. The rental companies in Singapore typically want to be able carry more counterweight.
"We have charts that show what is supposed to be on the crane, for us this is alright. We get checks by the authorities on seven or eight axle cranes; they normally only travel at night. If crane users get fined for travelling over-weight, they get blacklisted. So rental companies tend to play by the book.
"For Singapore, we are right hand drive. Most of the cranes from Germany are left hand drive. So, customers can’t get permits for road travel for smaller cranes, unless it is for a special job. For anything smaller than four axle on public roads, customers will use truck cranes.
"In Hong Kong, all terrains are not classified as on road vehicles, where only 10t per axle is allowed. To move all terrains, special permits must be applied for and the axle load be requested. They will usually start with 12t per axle but could go up to 15t: it is unusual if it is not approved."
Making it work
Around the world, customers and manufacturers take a range of approaches to getting their mobile cranes on the road within axle load limits. Meissner says, "More and more companies are asking for cranes with truck-style axle loads and spacing. That means cranes like the Roadmaster: all terrain booms or superstructure on a truck carrier. That’s one reason for taking that direction with our designs. The other is that using standard parts cuts lifetime cost of ownership. But it’s not as compact as a standard all terrain: a five-axle Roadmaster has a capacity equivalent to a four-axle all terrain.
"In the medium term, design will move away from capacity and length to usability and speed of rigging. With our new choice of names for our cranes, we’re making clear that capacity is not the only criterion. That applies to the design for the Challenger, and also to the design for our biggest cranes. Even with the AC 1000, we were clear from the start that we wanted to be able to travel with the boom on and still be under 12t per axle. We always have transportability in mind."
Marsh’s fleet is made up of lower capacity cranes. He’s a big fan of one in particular, Tadano’s Crevo, or Crane Evolution, which allows his operators to make the most of the crane’s capacity in tight conditions. He says, "It’s an excellent crane, with a safe load indicator complying with Japanese regulations. It can go where other cranes can’t, as it has five positions for outriggers, and the SLI adjusts for outrigger position."
He also keeps an eye on the top end of the mobile crane range: "There is a move towards building with more lightweight materials, on areas like the decking, to allow for roading in a lighter configuration. With more axles, and by reducing the overall vehicle weight, so you can road very big cranes with counterweight. In the old days, would have to always remove counterweight. The new Liebherr 750- tonner has been built like this to comply with European road regulations, with nine axles. It can be roaded at 12t per axle."
Manitowoc aims to make it’s crane as flexible as possible. Cremer says, "We’re doing a lot of design work to make all terrains roadable in the US and Australia. We offer quick connections for outrigger beams, making them easy to remove. On our larger cranes, we offer a removable outrigger box. The complete box can be removed in one lift. Only Grove offers this. On our seven-axle machines, we also have tag axles, to offer eight axles. That allows the crane to work in some regions where there are 10t or 9t axle load regulations."
"With the boom on a dolly in the US, you can sometimes have space for some counterweight on the dolly. So, then, the crane acts more like a taxi crane in Europe."
Haber says, "You might be able to road the crane with a boom dolly in Maryland, but then in Virginia, you will have to take the boom off, and carry it separately with another trailer. So, we offer a boom removal kit, with a quick connection, which allows customers to remove the boom in one hour. Customers can also buy a boom launch trailer, from Nelson Manufacturing in Ohio, which lets you take the boom off without a second crane. It’s like a slip, installed on a trailer, that pushes the boom all the way to the back, lifts it with a cylinder, grabs on a special point on the boom. Without a trailer like this, they would need a 50t-80t crane to lift the boom onto trailer."
