Introduction

The Finnish donor building of elements was a 7-storey office building located in the city center of Tampere, built in 1982. The plot had been re-zoned for housing by the City of Tampere. Therefore, project partner Skanska engaged it as a deconstruction pilot for ReCreate.

The donor building’s structure consisted of load-bearing columns and beam elements. Its floors were made of hollow-core slabs, and facades were sandwich elements. Deconstruction focused on the columns, beams and hollow-core slabs, as these elements were seen as most promising targets for reuse.

The Finnish partners cover the entire value chain in deconstruction and reuse. Demolition company Umacon has know-how on deconstruction works. A manufacturer of new precast concrete elements, Consolis Parma has engaged one of its factories for refurbishing the elements and is well-versed in quality management and logistics of precast elements. Ramboll Finland specializes in structural survey and structural design, both necessary for safe reuse. LIIKE Architects represent the architectural design sector, indispensable in configuring existing elements into new spaces and thus enabling the reuse from a functional perspective. As a construction company, Skanska will reuse the salvaged elements in new buildings in Finland. The City of Tampere, where the donor building was located, examines its public policy processes as a part of ReCreate to understand how a city can better enable deconstruction and reuse. Tampere University leads not only the whole ReCreate project but also the Finnish cluster and performs the associated research, including technical, environmental, sociological and business- and policy-related aspects. 

Deconstruction and Storage

Deconstruction of the donor building was planned in collaboration by the Finnish cluster partners. First, LIIKE Architects inventoried the available elements into a BIM model. Ramboll extended the structural model into a full-fledged deconstruction model for waste reporting purposes (part of the deconstruction permit). Ramboll devised a structural deconstruction plan, which entailed a coding system for the elements for later tracing, a safe deconstruction sequencing, necessary support measures, as well as instructions for disconnecting joints between elements. Deconstruction work planning, including work safety planning, was implemented in collaboration by Umacon and Skanska. They also implemented the deconstruction works together. A screed on top of hollow-core slabs was chiselled off before the elements were detached. Connections between hollow-core slabs were sawn with floor saws. Drills were used to detach beams, and chisels and saws to disconnect columns and wall elements. A tower crane was used to lift the elements to the ground level, where the elements were equipped with QR codes for tracing before transportation to storage. Storage takes place at a Consolis Parma factory, where the elements are also refurbished before reuse. 

Testing and Digitalisation

Testing of the elements was performed in two stages. Before deconstruction, Ramboll and Tampere university performed a pre-deconstruction audit in the building, which entailed a structural survey using non-destructive and semi-destructive methods. After deconstruction, destructive loading tests on elements were performed in the laboratories of Consolis Parma and Tampere University. The salvaged elements behaved expectedly under loading, i.e. in the same fashion as new elements. This denotes that the same calculation protocols which are used for new elements can also be used for recalculating salvaged elements’ structural capacity according to the currently enforced structural design code (i.e. Eurocode).

Check out the YouTube videos showcasing the disassembly and deconstruction of the Finnish donor building

Finnish Country Cluster Partners