Seismic and Energy Renovation of RC-Framed Buildings with Cross-Laminated Timber Panels Equipped with Innovative Friction Dampers

In the European seismic countries, most of the building stock is highly energy-intensive and earthquakeprone since it was built before the enforcement of effective energy and seismic codes. In these countries, renovation actions that synergically integrate both energy-efficient and anti-seismic interventions are strongly needed, looking at the resilience of buildings against earthquakes as one of the main values of a sustainable city. However, the implementation of such interventions is currently limited by barriers that are mostly related to the excessive costs and the high invasiveness of traditional seismic retrofit actions. To overcome these barriers, a new holistic design approach to the building renovation is required, which should result in innovative and integrated retrofit interventions able to specifically meet the needs of costeffectiveness, quick installation, reduced users’ disturbance, and low environmental impact. 

In this framework, this book reports a doctoral research work that was aimed at analysing the potentiality of a novel integrated retrofit technology for reinforced concrete (RC) framed buildings. The proposed retrofit system consists in cladding the existing building envelope with a new prefabricated timber-based external shell that acts as seismic-resistant and energy-efficient skin, contributing also to renovate the architectural image of the building. The new skin combines structural CLT panels – connected  to the existing RC frame through innovative friction dampers – with non-structural panels that integrate high-performing windows. The potentiality of the proposed  technology is analysed in terms of seismic and energy performance, and technical feasibility. Specifically, pushover analyses on a case study RC frame preliminarily  demonstrate the high potential impact of the proposed seismic retrofit system (CLT panels equipped with novel friction dampers) on the response of existing buildings to be upgraded. Hence, different prototypes of the friction damper are tested under cyclic loading, identifying the most promising in terms of structural efficiency. Dynamic thermal simulations on multi-story buildings, at pre- and post-intervention state, show the relevant energy efficiency of the system, especially in the winter. Moreover, the main technical issues related to the proposed retrofit technology are discussed to analyse its technical feasibility and versatility.