Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Engineering Science

Program

Civil and Environmental Engineering

Supervisor

El-Damatty, Ashraf

Abstract

Heavy timber is the upcoming and rising star in the construction industry in the European and north American market. However, this topic is yet to be discovered. Light frame wood LFW has been used for decades but was always restricted to certain limits. Limits that heavy timber can overcome easily. In this thesis, topics related to the application of heavy timber in the construction of buildings are searched. First, a comparative study based on the Canadian market discussing the alternatives heavy timber can offer such as glulam and cross laminated timber (CLT) in comparison with LFW when applied to mid-rise buildings. Different heavy timber structural systems were designed to have equal stiffness as the relative LFW building while achieving all the strength requirements, a cost comparison is carried out between the varying heavy timber systems and the LFW system based on the Canadian market. Second, an investigation is held based on the performance-based design concept for a 19-story glulam building, with a moment resisting frame as a structural system. The building is numerically modeled and exposed to real wind loads obtained from the Boundary layer wind tunnel laboratory (BLWTL). The moment connection shared characteristics based on tests conducted in the literature on a small moment connection. The wind loads are extracted from a previously tested rigid model at the BLWTL, and a time history analysis is performed. Following the time history analysis, decomposition of the wind components is conducted and a reduction factor is applied to the resonant component. A modified time history response is reapplied to the building and the new straining actions are evaluated. The connection’s hysteresis behavior is evaluated after applying the reduction factor. Furthermore, A parametric study is performed for two damping values. This thesis provides a conclusive study between heavy timber and LFW that discusses the ability of heavy timber to replace the LFW in commercial buildings. Also, it demonstrates the capabilities of heavy timber buildings to resist lateral loads such as wind loads in high altitudes granted that it is provided with an adequate structural system and a ductile connection that can dissipate the energy implied on it properly.

Summary for Lay Audience

The global demand for the use of sustainable materials has been rising rapidly over the past decade. There is a paradigm shift in the construction industry towards the green, biodegradable, and renewable materials. Heavy timber is definitely considered among those materials. Heavy timber has proven its superiority in many aspect such as being environmentally friendly and a better insulator when compared to steel, concrete, and light frame wood (LFW). In north America, most of the residential buildings consist of LFW. Heavy timber is capable of replacing LFW, while still having room to integrate vertically and reach high altitudes. This research is divided into two parts, each part discusses the potentials and pushes the heavy timber to its limits, in terms of using it as a renewable, biodegradable, and a clean material for construction. The first part is a case study that studies the replacement of LFW through Conducting a cost comparison according to the Canadian market between an existing multi-story light frame wood building (LFW) with two concrete cores acting as lateral load resisting systems and different structural systems of heavy timber, while achieving equal stiffness and satisfying the strength requirements. The second part of this research evaluates the possibility of allocating the heavy timber in a high-rise building without using another material as a lateral load resisting system. Most of the timber high rise buildings fail to resist the lateral loads resembled in seismic and wind loads, therefore, steel or concrete are used in these buildings as a lateral load resisting system. In this study, the potential use of ductility-based design is tested on a 19 story high rise moment resisting frame building that is numerically modelled, exposed to wind loads which are obtained from a previous test performed at the boundary layer wind tunnel laboratory (BLWTL), and its behavior is observed, while relying on the connections ductility.

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