Brokk Brings Efficiency to Driving Piles in Confined Spaces
Prior to a major renovation project and the construction of a hotel, the foundations of a historic 16,146-ft2 (1,500m2) building in Gothenburg, Sweden, needed to be reinforced. Built in the early 1950s, the foundations were piled with timber, which over time has begun to rot, causing the foundation to be compromised. Many cities are built on timber piles, which work well until exposed to oxygen. Soil conditions have a major effect, as does densification of cities. New buildings, road construction, and new landscaping near house facades disturb the soil, which in turn affects the timber piles. As a result, the foundations will often require reinforcement.
Project supervisor Richard Hammar of Grundia AB says that the project lasted about seven months. Early in the planning process, several challenges emerged, which resulted in a demolition robot being the only solution for the job.
“Some areas in the building are confined and sometimes difficult to access, the size, power, and flexibility of the Brokk made it an obvious choice,” Hammar adds.
As the work was to be carried out in a basement, the requirements were specific. The robot needed to get through passages less than 31.5 in (800mm) wide, and travel up and down stairs. The Brokk 200’s ability to deliver maximum power in relation to its size was crucial to this setting, as the task required the use of a large hydraulic breaker in a limited space.
And because the Brokk robots are remote controlled, the operator has the opportunity to maneuver the robot from a safe distance allowing the best possible view of the work. As the project was carried out entirely indoors, an electric powered machine was essential. The exhaust fumes from a diesel-powered machine would have made the work environment unbearable.
A Brokk robot is incredibly versatile thanks to the ability to use different attachments. When piling, the choice of hydraulic breaker may differ depending on the soil conditions and the state of the building; in this particular case a breaker with a large-diameter piston was needed. When using a heavy breaker, the robot needs a counterweight for good stability. With these types of jobs, where there is limited space and limited ceiling height, a side mounted breaker made it possible to maintain a high working pace. In addition, this type of breaker made it possible to maximize the length of each pile.
In total, Grundia AB laid more than piles on the building. The average depth was about 134.5 ft (41m), but varied between 56 and 130 ft (17 and 70 m). Due to changing ground conditions, some piles could be driven quickly, and others took several hours. For the deepest piles, the first 131 ft (40m) took about two hours, while the remaining 66 ft (20m) took almost four hours. Altogether, the Brokk 200 was used for 1,500 hours during the project.