The era of energy derived from fossil fuels is nearing its end. That is why a coal-fired power plant in Amsterdam was shut down in 2020 and dismantling began shortly thereafter. One of the last steps in the process was the plant’s 175-meter-tall stack, which a Tadano CC 38.650-1 recently tore down with a demolition robot on its hook. Crane service provider Sarens was tasked with the job by construction companies Combinatie ACGH consisting of LEK sloopwerken, Vermeulen Sloop en Milieutechniek and MNE Sloop & Demontage.
It was not the first time that Sarens had to tackle a job like this: “We’d already taken care of a similar demolition project in the Dutch municipality of Borsele with a Tadano PC 3800-1 back in July 2020. So basically, we were already familiar with the procedure needed for this kind of thing – as well as with the challenges and risks involved,” reports Sarens Project Manager Anton Mertens, who was in charge of the job and decided together with his team to use the Tadano CC 38.650-1 for it. The task involved lifting two different demolition tools, each consisting of a drive unit and a shear or breaker attachment, to a height of up to 175 meters and using them to dismantle the stack piece by piece from top to bottom. Throughout the process, the team had to constantly switch between the two demolition tools.
Special configuration required for the CC 38.650-1
The required configuration with a system length – including a luffing jib – of 196 meters and a lifting capacity of 25 tonnes at a radius of 55 meters was not one of the standard configurations found in the load charts for the CC 38.650-1. Accordingly, Sarens asked Tadano for help, and the latter suggested expanding the load charts for SWSL_3 with an additional main boom length of 108 meters in combination with the existing boom length of 90 meters. “Our initial analyses quickly showed that the CC 38.650-1 would be able to achieve the required lifting capacities without issue. So after we received Sarens’ go-ahead to retrofit their CC 38.650-1 accordingly, we completed the load charts and updated the LMI load moment indicator on the Sarens crane,” explains Tadano Manager AC & CC Retrofit, Christian Eickstädt. “This support from the manufacturer was absolutely vital for us, since the required crane configuration had never been put together before. Honestly, it was just impressive service, especially since everything had to be done within an extremely tight schedule,” underscores Sarens Lifting Supervisor Jerry Couvreur. And to complement that, Sarens was also able to count on on-site support from Tadano, with Tadano personnel from the Netherlands and Germany present at the work site throughout the entire assignment.
Ultimately, the team was able to set up the CC 38.650-1 with the required SWSL_3 configuration with a 108-meter main boom featuring a 84 m Boom Booster, and a 90-meter luffing jib. Meanwhile, the counterweight was split into 225 tonnes on the superstructure, 50 tonnes of central ballast, and 245 tonnes of SL counterweight. For the 54-tonne SWL hook blocks, the Sarens team used a two-pronged approach: one with three wire ropes and one with only a single one. “The reason we chose these two hooks with their respective reeving setups was the low own weight, their fast hoisting speed and how that would enable us to minimize non-productive times when having to switch between demolition tools,” Anton Mertens explains.
Crane set up in a mere five days despite special configuration
Sarens brought the CC 38.650-1 from its headquarters in the Belgian town of Wolvertem, which required a total of four days and more than 50 truck runs. Three assembly technicians took care of the setup itself within five days, with the occasional assistance of one or two crane operators. Once the crane was assembled, there was a rigorous inspection, multiple cameras were installed on the jib tip, and a monitor was installed in the cab in order to allow crane operators to get an optimal view from all angles during the demolition work. This group of tasks took a total of two days. “When you consider the fact that we used a configuration that had never been used before and that we had to get a number of components from a different location, I have to say that we’re really happy with how the setup process turned out – especially since we had to make sure we wouldn’t be disrupting any other ongoing demolition work at the site,” Anton Mertens succinctly puts it.
Extensive preparations for lifts
The lifts themselves involved a whole series of challenges as well. One of them was safety – especially due to the constant danger of debris falling from a large height during teardown. In order to handle this, the team set up a double series of containers in front of the crane in order to protect it from any falling or deflected concrete rubble. They also protected the crane cab with a transparent cover protection. “On top of that, we took a look at a wind analysis and chose a crane position that would make it highly likely for the wind to blow from behind, which would help minimize the risk posed to our crane operators by falling debris,” Anton Mertens says. If the wind came from the wrong direction or was too strong, the demolition work was stopped. Wind conditions were a particular concern on this job: If maximum wind speeds were forecasted, the boom had to be lowered as quickly as possible. This process had to be carried out with particular care, as an anti-dust spray system was attached to the crane’s boom. “That component in particular made it necessary to pay very close attention when raising and lowering the boom so as to be able to prevent collisions and damage,” explains Anton Mertens.
Ambitious project targets achieved
Despite the numerous constraints, the purchaser and Sarens agreed on an ambitious demolition target of five meters per day. This meant a timeframe of ten weeks for tearing down the stack, which in turn meant that the crane would be at the work site for ten weeks. The lifts themselves followed a circular pattern around the edge of the stack and had a crane operator and a lifting supervisor work together at all times. Meanwhile, the CC 38.650-1 itself was truly put to the test, as it had to handle 16-hour days and two shifts as a general rule. Nevertheless, the crane handled it like a champ, enabling the team to finish the work on time and consign the previously prominent stack at the Hemweg 8 coal-fired power plant to the dustbin of history.
