Vibrations induced by people walking is one of the most important issue in timber floor design. Low natural frequency and low mass require a careful analysis in order to prevent significant annoyance and to guarantee an acceptable human comfort. This paper is concerned with the assessment of vibration performance of a timber-concrete composite timber floor and a cross laminated timber floor used in two timber buildings under construction in Trento (Italy). Different approaches suggested by Standards and literature were employed: analytical methods, numerical analyses and laboratory tests. About analytical methods the uniformed distributed load deflection criterion (ULD), the Eurocode 5 criterion and some criterions from literature were compared, whereas the Vibration Dose Value (VDV) method, as suggested by ISO 10137, was used for the numerical models and the laboratory tests. The numerical analyses were carried out by means of a finite element modelling. The load due to footfall was simulated by static and dynamic vertical forces. The laboratory tests were characterized by thirty walking tests for each floor. Impact testing with modal hammer was also undertaken in order to investigate the dynamic properties of the specimens. All results are compared and discussed.
Second European Conference on Earthquake Engineering and Seismology
August 25-29, 2014, Istanbul, Turkey
In the past, while wood as a natural building material was preferred for only housing construction, today, engineered wood products are used as structural elements even in many different projects such as, schools, airport terminals, stadiums or indoor sport centres and finally in multi-storey houses nowadays. On the other hand, the sustainability is becoming a key focus. Engineered wood products are increasingly used for earthquake resistance as well as natural insulation and sustainable design. Recent studies indicate that the earthquake resistant design through engineered wood products is achievable and affordable. The seismic design of structures typically depends on the ductility of members and connections. The innovative design techniques with wooden composites ensure that the building is functional after a major earthquake event. Within the scope of this study, the earthquake resistant design approaches and experimental results of New Zealand, Canada and Italy are addressed for multi-storey wooden/wooden-hybrid structural systems. Member and connection types, posttensioning effectiveness, floor systems, sustainability and constructability will be focused.
The Italian building heritage is aged and inadequate to the high-performance levels required nowadays in terms of energy efficiency and seismic response. Innovative techniques are generating a strong interest, especially in terms of multi-level approaches and solution optimizations. Among these, Nested Buildings, an integrated intervention approach which preserves the external existing structure and provides a new structural system inside, aim at improving both energy and structural performances. The research presented hereinafter focuses on the strengthening of unreinforced masonry (URM) buildings with cross-laminated timber (CLT) panels, thanks to their lightweight, high stiffness, and good hygrothermal characteristics. The improvement of the hygrothermal performance was investigated through a 2D-model analyzed in the dynamic regime, which showed a general decreasing in the overall thermal transmittance for the retrofitted configurations. Then, to evaluate the seismic behavior of the coupled system, a parametric linear static analysis was implemented for both in-plane and out-of-plane directions, considering various masonry types and connector spacings. Results showed the efficiency of the intervention to improve the in-plane response of walls, thus validating possible applications to existing URM buildings, where local overturning mechanisms are prevented by either sufficient construction details or specific solutions. View Full-Text
Timber buildings are characterized by a thermal inertia lower than other technological solutions in construction. For this reason, some configurations may lead to higher cooling demand and poorer energy performance in hot climates, such as the Mediterranean ones. Possible improvement interventions often regard additional thermal mass but, if not accurately designed, they can worse significantly structural and seismic perfo rmance of timber buildings - which is of primary importance in many Italian regions. In this framework, the TimBEESt project studied some technological solutions for timber buildings in Light Timber Frame and Cross-Laminated Timber, able to improve the dynamic behaviour of the opaque components without worsening their seismic performance. First, the Italian territory was analysed in order to find classes of climate and seismic solicitations and energy and structural performances of reference LTF and CLT building models were simulated. Then, for each Italian province, specific interventions and improvements were defined and evaluated.