Delete demolishes Stockholm lock

Published 15/11, 2017 at 18:17

Delete, one of Sweden’s biggest demolition contractors, is dismantling the 80 year-old Slussen lock in Stockholm that connects Saltsjön, a bay of the Baltic Sea, with lake Mälaren. The lock will be replaced with a new structure and the whole project is expected to take nine years to complete and will cost at least €1.2bn. PDi editor in chief Jan Hermansson reports.

The Swedish demolition industry is becoming internationalized. The jobs are getting bigger, the demands on entrepreneurs increasing and legislation strengthening, which requires bigger players. This often leads to smaller companies collapsing and forming larger and stronger players. In recent years, there have been clear signs of this development, even in Sweden. In countries such as the UK, Germany and France, this has been going on for quite some time.


The acquisition of Demcom

Delete is an excellent example of a company development that began in Finland and spread to Sweden. The company's wave of acquisitions started in Finland and continued in Sweden with the purchase of a number of medium and large demolition, rehabilitation and recycling contractors. The goal was reached when Delete acquired Demcom in Örebro, which was as large as the company's own demolition operations in Sweden.

With the assets in personnel skills and equipment that were available in Delete from the beginning, and what they have acquired, they have established as a very strong and knowledgeable player in the market on par with the really big players around the world.  Delete now has the capacity and competence to take on big and demanding assignments and a good example is the demolition of the Slussen lock.


The Slussen lock project

Anyone who has passed the Slussen lock in recent years can probably agree that it was in a very bad condition.  The traffic site, built 80 years ago, that united pedestrians, cyclists, cars, subway and boat traffic, needed to be demolished and rebuilt. Here every day hundreds of thousands meet. Only the subway carries about 270,000 people a day through Slussen. The new Slussen has to be built to meet current and future needs from commuters in Stockholm. 

The future Slussen will be a safe hub for pedestrians, cyclists, motorists and public transport. It is also thought to become one of Stockholm's most attractive meeting places with park life, entertainment and culture, restaurants and cafes. The new Slussen will also have a five-fold capacity to discharge water from Lake Mälaren to Saltsjön, to reduce the risk of flooding in Stockholm and in the Mälaren valley. This will also ensure water availability for the approximately two million people who get their drinking water from Lake Mälaren. 

The financing of Slussen is managed by Stockholm City. To regulate water levels, other municipalities around Mälaren will probably be part of sharing the costs. The rebuilding of Slussen started in 2016 and will last until 2025. The project is expected to cost €1.2bn.

There are many companies involved in the Slussen project. During the construction phase, the project will employ over 500 people directly and many more indirectly. The head of the two largest projects within the overall project is Skanska. The first project relates to the works in connection with the quay facility, which includes demolition, grinding, laying, foundation, concrete and steel construction. Delete Sweden was appointed for the demolition in the first project. The second project involves Slussen's new construction at Södermalm, which is the southern suburb of Stockholm inner city. More demolition stages are planned as the project progresses.

A Swedish demolition veteran embedded in the project because of his long experience and a senior consultant and senior advocate at Delete is Lars-Olof Dahl. "Slussen is truly a prestigious project for us and we are pleased to have gained confidence. At the same time, I know that we both have the knowledge and resources as few others in Europe. The big challenge with this job is the logistics as I see it,” said Dahl. 

Just getting the logistics to work was more difficult when the project started. In the area there were a lot of cruise ships and ferries. At the same time, a lot of Stockholmers tried to find their way to the work, to buses and the subway, right on the same spot where both demolition and construction work was taking place. “Before all signage, it was a bit messy. But the Slussen job is a bit of a dream project for us. The site's history and location, as well as our mission in it is gold for us," said Dahl. “The Slussen project was not very technical and it was not so different to other demolition projects. Most important was to figure out a way to transport all the waste from the site in a calm and sensible way so that no third person suffers too much."

Another key person in the Slussen project is Marko Pääkkönen, who is production manager for the demolition activities at Delete. Stage 1 of the Slussen project is complete. "Now we are starting with new challenges around Stockholm and the rest of Sweden," said Pääkkönen. 


Silent demolition with little vibration

A lot of hydraulic concrete crushers were used and as few hydraulic breakers as possible. This was to minimize the noise in the city centre. On average, Delete had four employees on site and three demolition excavators, one 60t and two 30t. The concrete and reinforcement that was demolished was separated on site and then loaded onto trucks and transported to Västerhaninge, south of Stockholm, where the reinforcement was completely separated and the concrete was recycled. Afterwards the crushed concrete was reused and the reinforcement went to scrap. 

"On this project, I would estimate that we had a total recovery rate of 98% to 99%,” said Dahl. “The road from Slussen to the recycling site is BK1-rated, which means that Delete could drive fully loaded cars while reducing the amount of trucks that ran in and out of the city. It was a very big advantage from an environmental standpoint that we could halve the number of trucks." At first a lot of demolition waste was stored onsite and this was followed by weeks of transportation and recycling. An estimated 5000m3 of concrete has been demolished and recycled so far. In January next year, Delete will launch stage 2 of the project, which is as extensive as stage 1. Both stages deal with the demolition of two bridges at Slussen, demolition of monoliths consisting of columns, beams and concrete slabs. 

Main contractor Skanska chose Delete for the demolition.  "In this type of extensive project where many different parameters are relevant to the performance itself, there are usually many things that capture why you choose an entrepreneur before others. We estimated that Delete had both the technical capabilities and the great experience needed to perform this type of job correctly. In addition, Delete has the competence to perform both environmental management and heavy demolition. This in relation to the price is of course also important in selecting a demolition contractor," said Skanska Slussen project manager Martin Klimt.

What was the reason that Skanska chose Delete for the mission to demolish Slussen? Martin Klimt, project manager for Slussen from Skanska and Mats Omnell, Site Manager for the project who had the daily and on-going contact with Delete at the Slussen project during the demolition stage, can best answer this question answers:

“Delete was involved at an early stage of the project, which was important and we could then discuss solutions together,” said Skanska site manager Mats Omnell. “It wasn’t an option to divide the demolition job to various entrepreneurs and had neither improved nor become cheaper. For this demolition it was imperative that just one contractor should be in charge.”


Slussen no homogeneous construction

Dahl said that Slussen is not a homogeneous construction and therefore differs from many other demolition jobs and was more complex. "This meant that the demolition work had to be done in exactly the right order. The conditions are also changed sometimes, even though you have a detailed demolition plan, and it would be even more complicated if the demolition task had been outsourced to several contractors," said Dahl. 


Short facts about Delete

Delete in Sweden currently has its headquarters in Umeå in the north of Sweden and has 300 employees. The company's turnover in 2016, was approximately €50M. Delete in Sweden is part of the Finnish Delete Group, which is owned by the Danish private equity company Axcel. The business is focused on several service sectors, which include industrial restructuring, explosion dumping, demolition and concrete cessation, recycling, and remediation and damage services. The machine fleet consists of punching equipment, demolition robots and demolition excavators up to 140t than reach to a height of 46m. 

All machines are equipped with the necessary tools such as hydraulic hammers, shears, crushers, and grapples. 

Delete is certified to ISO 9001 and 14001 and was also certified by OHSAS18001 in 2016. The company is authorized to clean asbestos and PCB and permission to transport hazardous waste by road. The acquisition of Demcom Demolition in 2016 meant a significant capacity and sales increase. Delete intends to continue to grow both organically and through new acquisitions in the coming years.


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