State-of-the-Art Report on high reversible timber to timber strengthening interventions on wooden floors

The goal of this State-of-the-Art-Report (STAR) on high reversible strengthening interventions on timber floors is to give an overview of the new techniques developed and tested to achieve in-plane and out-of-plane stiffness upgrading by means of less invasive and reversible interventions. In recent years a growing sensibility towards the preservation and maintenance of heritage buildings has led researchers to test different dry retrofitting systems. The report focuses on strengthening interventions based on the use of wood or wood based elements: the most adopted or most promising techniques are so briefly described.While the problem of upgrading the bending stiffness has a solid analytical background in the concrete-to-timber composite section theory, the problem of upgrading the in-plane stiffness still requires attention. The importance of the correct evaluation of the in-plane mechanical properties of floor timber diaphragms is nowadays clearly assessed in order to determine the building structural response under lateral seismic loads. In some codes, simplified analytical procedures are proposed to determine the in-plane stiffness, but generally, with regard to new timber building floor typologies. The tests described in literature are generally referred to different setups, test rigs, boundary conditions, aspect ratio of the floor samples and also the recorded parameters are not always the same ones: it is so difficult to compare the experimental data as to achieve a general stiffness evaluation approach.