Last year, the economist reported that one in three railway bridges in Germany is more than 100 years old and added that in the US the average bridge is 42 years old. Although America’s infrastructure has not been considered a national priority for many years, another report from the American Society of Civil Engineers highlighted the urgency, with 151,238 of its bridges as ‘deficient’. Crumbling infrastructure is not only dangerous, but can debilitate a TBM move through a city.

Concerns about the infrastructure market have been triggered by tragic failures of existing infrastructure – such as the collapse of the 40-year-old 35W Mississippi River bridge, which killed 13 people and injured 145 in Minneapolis.

“It’s getting tougher and tougher in the marketplace,” says Jon Eaton of Wallenius Wilhelmsen Logistics Abnormal Load Services (WWL ALS). “There’s not a lot of investment going into the infrastructure, a lot of bridges that you could once go over with a certain tonnage are now being reduced in tolerance levels. It means having to find different routes, which may mean more street furniture has to come out or a longer way around it. Or putting more axles onto the trailers, because the bridge teams will tell us we need to be at 11t per axle and we then have to add or subtract axles to meet that level. For example, we had a route signed off, twice in fact, for a TBM going from one of the Crossrail sites back into Germany. But then the machine got delayed in the tunnel and by the time we reapplied to use this route one of the structures got downgraded, which meant that all the work we put in to find the route went out the window. We had to find another route. That’s one of the problems we face at the moment, investment in the actual infrastructures.”

Today’s TBMs are getting bigger, pushing the limits that a city can accommodate. A 17.6m diameter machine by the Dragages/Bouygues JV for its design-build contract to excavate the 4.2km long undersea Tuen Mun – Chek Lap Kok Link highway project in Hong Kong, is now the world’s largest TBM. The TBM is marginally larger the 17.48m diameter Hitachi Zosen EPBM on the Alaskan Way viaduct replacement highway tunnel project in Seattle.

In 2013 WWL ALS delivered the TBM Jessica from Stepney Green, through to Limmo Peninsular in east London as part of the Crossrail’s Eastern Tunnels contract, C305. The contract from the contractor Dragados Sisk Joint Venture (DSJV), was to transport the 1,300t Herrenknecht S-721 TBM and backup equipment in as large individual components as possible. Extensive surveys were undertaken by WWL ALS to determine possible routes for this project. As part of this planning process innovative 3D laser mapping was used on dual carriageway sectors of the route with high traffic density, for scanning overhead gantry, bridge and tunnel heights and widths where manual means of checking clearances would be too hazardous. The route taken by all loads was eastbound via the A13 Limehouse Link Tunnel, with a height and width clearance of just a few centimetres for the largest items.

“We spent two nights in the tunnel measuring it, making sure that we were not going to bang into the ceiling,” says Eaton. “It’s always nerve wracking when you’ve measured it, but before we left the site we were erected with scaffolding that was just lower than the bridge height, and we knew if we fit under that then we should just fit in the tunnel. It was another exercise to make sure we had done our homework.”

Downtown San Francisco

For the San Francisco Municipal Transportation Authority (SFMTA) Central Subway project, part of the contract for Contex Shipping was to transport two TBMs from San Francisco Pier 80 three miles downtown to the jobsite, Fourth Street between Bryant and Harrison Streets. Since Pier 80 does not have heavy lift cranes, the firm had to discharge the pieces with the vessel’s gear and load directly onto the trucks. To move the 130t piece Contex Shipping had to rent two mobile 350t cranes to lift from the vessel onto a Goldhofer truck.

“We had to bring the TBMs from the pier through Chinatown, which of course is a busy area, to the jobsite. Every time there was a concert on we couldn’t move the machine, and we also had travel curfews during baseball games and rush hour. We travelled mainly at night,” explains Bennet Riemeier, VP, Contex Shipping. “One time, we had to cancel a tuck transport because there was a concert that went on longer than planned, and then there was too much traffic. We had to park trucks with the components next to the shaft and wait until the job site was allowed to open the shaft. The shaft that we had to lower the machines into was under a highway; so during the day and rush hours it was covered in order for traffic to flow.”

Contex Shipping handled the total transport of two, 6.3m diameter EPBMs from Robbins’ manufacturing facility in Guangzhou, China, to the jobsite. Riemeier adds: “It took us a day or two to load the barges in China, then it was 10 to 12 hours travel to Hong Kong.

It then took a day or two to load the ocean vessel, and a further 32 days to travel from Hong Kong to San Francisco. “The challenge was to coordinate with the barge company the loading address, and the ocean vessel in Hong Kong to be there at the right time in order to avoid detention charges from either barge or ocean vessel operator. You never want to have an ocean vessel wait somewhere for your cargo; either you pay detentions to the ocean vessel, which you really don’t want to do, because otherwise you’re looking at USD 30,000 to USD 40,000 per day, then on the other hand you don’t want to have your cargo sit there for 10 days or longer and wait for the ocean vessel because the barge costs money every day too.”

With a complex TBM delivery, Riemeier explains that a freight forwarding company is a clear path to take. “When you have just a container from port to port, that’s easy to do that by yourself, you’ll probably get cheaper rates. But when you have a USD 30M project, you don’t want to deal with several companies. Our great advantage is that we’re in this market and we speak to these companies every day. For the San Francisco project we were dealing with the barge company, the trucking company in China, the port operators, the shipping line – there are so many different people you need to talk to in order to get this transportation accomplished. It’s hard for a company that is not focussed on these things such as TBM manufacturers, which are more honed in on creating these machines.”