Proceedings of International Structural Engineering and Construction, 7(2), 2020 Emerging Technologies and Sustainability Principles Edited by Askarinejad, H., Yazdani, S., and Singh, A. Copyright © 2020 ISEC Press ISSN: 2644-108X STR-20-1 STORY VERTICAL POST-COMPRESSION FOR TIMBER BUILDINGS: A NEW SYSTEM FOR SEISMIC IMPROVEMENT OF CLT WALLS ALBERTO VISKOVIC, FEDERICO DI LISIO, and PIERGIORGIO MICHETTI Dept of Engineering and Geology, University G. D’Annunzio of Chieti-Pescara, Italy A new constructive system for multi-story timber building with CLT panels is described. A vertical post-compression of each story allows avoiding the use of traditional joints, as hold-downs and angle brackets. Reducing the number of joint elements, the new constructive system may be faster than the traditional one. The story vertical post-compression allows to improve a shear-type behavior of each story with better performances of the CLT panels. Numerical studies on a single panel and a five- story building are made performing pushover static equivalent nonlinear analyses. These studies show as the new system allows better performances, in the case of horizontal actions, in comparison to the traditional constructive use of CLT panels. Thus, the new system is very suitable, for timber buildings, in areas prone to seismic actions and wind actions. Keywords: Seismic and wind actions, CLT panels, Pushover analysis, Single panel analyses. 1 INTRODUCTION Timber walls with “story vertical post-compression” represents a proposed new way to design buildings in areas at earthquake risk. Timber post-compression was studied in the last two decades mainly to improve the bending behavior of beams in frames (Newcombe et al. 2010, Smith et al. 2012) or in multi-story column-panels (Sarti et al. 2014). The proposed solution explores the advantages to improve a shear-type behavior in each story and to eliminate the traditional joints. Cross-laminated vertical timber panels are post-compressed by vertical post- tensioned bars placed outside them and in the building corners. The constructive system is made up of two verticals coupled CLT panels, by horizontal coupled beams and by the steel vertical bars connecting the beams (Figure 1a). The coupled beams may be made of glulam or steel. The steel bars are fixed to the steel elements that couple the beams. Each bar connects only two subsequent floors; thus, its diameter and its post-tensioning may be calibrated for each story differently from the other story and according to the resultant vertical load and the horizontal shear action. The purpose of this constructive system is to substitute the connection elements between panels and the connections to the foundation (i.e., hold-downs and angle brackets) through the bars post-tensioning, in such a way to avoid damages to those connection elements, to the screws or bolts and to the CLT panels themselves (Ceccotti et al. 2000). To validate the system, a single panel and a five-story building were numerically analyzed. Pushover analyses show the better behavior of the post-compressed single panel and building in comparison to the traditional connection techniques.