International Journal of Design & Nature and Ecodynamics
Technological developments and social trends can create demand for new building functionalities, necessitating the adaptation of existing buildings. This paper presents the development of a modular building structural system that provides for the harmonization between the structural and functional lifespans of a building in order to achieve greater sustainability. The limitations of the existing prefabricated urban buildings with respect to their adaptability are contrasted with the proposed solution. The use of prefabricated engineered materials, such as cross laminated timber (CLT) and CLT-concrete composites, in conjunction with a modular system, reduces any climatic effects. The inherent advantages of incorporating detachable connections allows for the necessary structural adaptability, subsequently harmonizing and elongating the structural and functional lifespans. The resulting sustainable concept, when applied to residential buildings, could serve as a solution to address projections of future urban growth.
This paper deals with laminated timber-concrete (LTC) composite beam members, for applications in sustainable building structures, in which the interlayer connection is achieved with adhesives, similarly to the glued laminated timber beams, instead of the classically used shear connectors (e.g. mechanical connectors or notches). Only a small number of studies of this type of high-performance members are available. The strength and stiffness of the LTC under short-term static ramp-loading were studied on new and retrofit (joist-type) floor members, through laboratory tests and non-linear finite element modelling. In the initial tests the typical failure mode observed was the failure of the wood in tension. Consequently, a carbon fibre reinforced polymer (CFRP) layer was added to the tension side of the timber layer, forming a multi-composite member. The research results indicate that the structural performance in terms of efficiencies and strength for the LTC beams exceeds the corresponding performance of similar classical timber-concrete beams with shear connectors due to the different shear transfer and failure modes. By adding the CFRP reinforcement to the tension fibres of the timber layer, the failure mode changed again, allowing for further increase in strength and stiffness.