Even a demolition requires careful planning
The dismantling of high-rise buildings usually places special demands on the stability and flexibility of the scaffolding – especially when exceeding the heights permitted by the general building authority approvals.
Such was the case during the demolition of the education campus in Halle. In order to meet the specific requirements as well as the requirements regarding the building’s height of 44.0 m, those responsible opted for a technically sound scaffolding solution, erecting a working scaffold of width class W06. Approximately 8,500 m² of the proven ALFIX 70 facade scaffolding was used, in combination with ALFIX steel frames and ALFIX steel decks. The installation was supplemented with dust-control netting to optimally meet the conditions of occupational safety and dust emission control during the dismantling process.
Scaffolding with the proven ALFIX 70 facade scaffolding during the execution of demolition work
Photo credit: City of Halle (Saale) / Thomas Ziegler
Since the standard configurations specified in the national technical building authority approval (here Z-8.1-862) typically only consider scaffolding systems up to a platform height of 24.0 m, the ALFIX GmbH Technical Department was consulted for this construction project reaching a height of 44.0 m. Together with the scaffolding specialists from the company Gerüstbauunion GmbH in Peißen, a scaffolding structure was planned that was adapted to the construction site and the specific project. The structure met the static requirements while also enabling an efficient demolition work.
The primary consideration was to assess the permissible standard loads at the specified bay widths and to derive necessary stabilising measures from this assessment.
A key focus of the planning process was the development of a structure-specific anchoring concept. Due to the building’s exposed height and the associated wind loads, the anchor grid was adjusted to meet structural requirements and the number of anchor points was increased. Particularly in the lower third of the scaffolding structure, it was necessary to transfer the additional loads from the scaffolding’s own weight resulting from the structure’s significant height. Accordingly, a denser spacing of the anchor grid in this area was designed and implemented, and the system was further strengthened using additional diagonal bracing.
In order to ensure the economical and efficient implementation of the construction process, the scaffolding construction was designed so that the top 4.0 m could be temporarily free-standing during the demolition process in each 4m phase. This required precise logistical coordination with the demolition company to dismantle the scaffolding continuously and promptly as the deconstruction process was carried out.
To safely absorb and transfer the loads of approximately 30 kN per frame on the canopies of the building entrances, a structure using the ALFIX MODUL MULTI 4.0 system was erected. This highly load-bearing modular scaffolding system, notable for its wide range of connection options, offers great flexibility and adaptability in its application. For this project, this system was fitted under the ceilings of the entrance areas to be used as a load-bearing scaffold in a 1.09 x 1.09 m grid.
Despite the considerable amount of material used – around 100 tonnes on a scaffolding area of approximately 8,500 m² – the highly efficient team of three scaffolders from Gerüstbauunion GmbH were able to complete the assembly in record time. Within one other week, the entire structure was then enclosed with dust-protection nets in order to effectively protect adjacent areas from dust emissions.
To ensure the continued material logistics and personnel transport regardless of the state of the building structure (lack of power supply to the building, blocked stairwells), two stair towers were installed on the gable ends starting at a height of 5.0 m. These served as construction site access stairs with a load assumption of 200 kg/m² and were constructed using the module scaffolding system ALFIX MODUL MULTI 4.0 in combination with ALBLITZ aluminium platform stairs.
Additionally, two construction hoists with load-bearing capacities of 500 kg and 1,500 kg were installed centrally on the longitudinal sides. To serve as connecting elements between the hoists, the respective scaffolding levels, and the building interior, a continuous scaffolding tower with a surface area of approx. 15 m² made using ALFIX MODUL MULTI 4.0 was erected on both sides of the building. The height difference between the levels was compensated for by using special stair solutions, which served also to create standards-compliant access routes.
The project demonstrates how, through the targeted use of proven scaffolding technology in combination with closely coordinated technical planning alongside the manufacturer, a high degree of safety and efficiency can be achieved, even under challenging operating conditions.
Using static calculations, 3D visualisations (such as those from the project in Halle, which can be seen here https://autode.sk/43CmUUA), as well as the creation of detailed assembly plans complete with corresponding parts lists, a safe and efficient implementation of the client’s requirements is ensured already in the planning phase. The ALFIX project department develops client projects in meticulous detail already in the planning phase using computer software, and these models are made available to the user to facilitate a structured and smooth process.
In addition, the postcode tool allows for quick and direct access to the appropriate contact person in each respective region simply by entering your postcode on the ALFIX GmbH website.