Durability and Longevity of Timber Buildings

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DURABILITY AND LONGEVITY OF TIMBER BUILDINGS

Research interest in innovative timber building systems suitable for multi-storey structures has largely increased in the last years, due to the increasing popularity of high-rise timber buildings. In this context, RP3 focuses on the development of a novel, digital wood building system, which allows a high degree of freedom in the structural grid, overcoming the design limitations of standard building systems, characterized by rigid grids as ordering systems.

In particular, a new column-to-slab system, consisting of cross-laminated timber (CLT) and glued laminated timber (GLT) elements, was developed, based on high optimization of the individual components. The connection is composed by two tailor-made beech LVL inserts glued into cavities at each side of the CLT (spruce) plate. A real-sized specimen was manufactured and its mechanical performance (load capacity and failure mode) was experimentally tested at the Materials Testing Institute (MPA) of University of Stuttgart.

Innovative timber (hardwood/softwood) composite systems have many advantages with respect to traditional reinforced concrete or steel–concrete composite systems, including: (i) lighter structures; (ii) sustainability; (iii) and good predisposition to prefabrication, with reduced construction time and costs. However, the different mechanical and hygroscopic properties of the two wood types greatly influence both the short- and long-term performance of the composite.

So far, limited experimental data are available on the long-term performance of such systems under variable environmental conditions (relative humidity (RH [%]) and temperature (T [°C])). This aspect is really important and should be properly taken into account in design.

With these premises, the new research project (RP23-1) is aimed at providing more insight into the complex hygro-thermo-mechanical behavior of timber composite (hardwood/softwood) systems through experimental study and development of a novel and reliable material modelling approach. The developed numerical model, supported by experiments, will support the design through derivation of durability functions/factors which account for the influence of relative humidity (RH [%]) and temperature (T [°C]) on the long-term performance of the timber composite systems. The project goals foresee a close cooperation with RP 3-2.

PRINCIPAL INVESTIGATORS

Dr. Serena Gambarelli
Materials Testing Institute (MPA), University of Stuttgart
Prof. Dr.-Ing. Jan Knippers
Institute of Building Structures and Structural Design (ITKE), University of Stuttgart

TEAM

Rey-Noe Fararoni-Platas (MPA)
Gregor Neubauer (ITKE)