# On the Role of Seismic Damage Tolerance on Costs and Life Cycle of CLT Buildings
## 1 Introduction
2014 [23], proposed a damage-tolerant slip-friction device that works as a tensile-resistant element when placed at the base of CLT walls, while [PERSON] et al. 2016 [24], introduced damper-based HDs using high force-to-volume damping devices made of a steel shaft sliding within a tube. [PERSON] et al. 2021 [25], proposed a novel low-damage and replaceable connection made with a friction-based device for CLT rocking structures integrated with springs to allow the recentering of the shear wall. The conceptual design of the connections plays a key role in the combination of the seismic damage limitation and tolerance, and overall costs, including those associated with the structural maintenance, reduction and optimization of the Life Cycle process for CLT buildings (Figure 2). In this framework, structural solutions oriented towards damage control in structural and non-structural components, cost reduction related to demolition of structural and non-structural components and improvement of the aspects influencing  
Figure 1: Typical failure modes and damage in connections made with hold-downs and angle brackets: (**a**) [PERSON] et al. 2029 [12], (**b**) [PERSON] et al. 2019 [13], (**c**) [PERSON] et al. 2021 [15]. the LCA should be selected in engineering practice. Moreover, both in the case of new or existing buildings designed with rules that are obsolete or not codified, BIM tools can also be useful to include in the overall design process, allowing management of the damage control, repairing, costs and Life Cycle of buildings [26]. In the field of timber-based structural solutions, studies devoted to investigating the role of the design approaches of the connections and technological construction technologies on structural behavior, expected damage, costs and sustainability of the structural system have not been yet addressed. This paper presents a first insight into the relationship between these aspects for CLT buildings erected in seismic-prone areas, and its aim is that of promoting a discussion within the scientific community concerning this particular task. The main research objectives can be summarized as follows: (i) to highlight the role of construction technologies and design criteria of the connection between damage tolerance, construction costs and Life Cycle aspects; (ii) to analyze the influence of damage-tolerant connections between the overall seismic behavior of CLT buildings, costs and Life Cycle; (iii) to explore the crucial role played by the non-structural components in terms of costs, damage level, architectural features of buildings and Life Cycle. In this respect, comparative analyses between traditional and damage-tolerant CLT buildings have been conducted. A real two-story CLT school building located in northern Italy was considered a sample building, with its seismic design varying the geometry of the walls and typology of connections. A comparative analysis of the different structural layouts was performed depending on the results of nonlinear static analyses (e.g., pushover). Research outcomes allowed some reflections on the relevance of optimized and integrated design procedures for CLT buildings, highlighting the major role of the connecting system design on the overall structural response of the buildings in terms of seismic capacity, ductility, damage control and tolerance, construction costs, impact on the Life Cycle performance of the buildings and interaction with architectural and non-structural features.