It is not surprising to see a rapid growth in the demand for mid- to high-rise buildings. Traditionally, these types of buildings have been dominated by steel and concrete. This trend creates a great opportunity for wood to expand its traditional single and low-rise multi-family building market to the growing mid- to high-rise building market. The significance and importance of wood construction to environmental conservation and the Canadian economy has been recognized by governments, the building industry, architects, design engineers, builders, and clients. It is expected that more and more tall wood frame buildings of 6- to 8-storeys (or taller) will be constructed in Canada. Before we can push for use of wood in such applications, however, several barriers to wood success in its traditional and potential market places have to be removed. Lack of knowledge of the dynamic properties of mid- to high-rise wood and hybrid wood buildings and their responses to wind, and absence of current guidelines for wind vibration design of mid- to high-rise wood and hybrid wood buildings are examples of such barriers.
This report summarises results from the first year study of this project and from other two one-year related projects. The main objective of the study was to build a framework for the development of design guide for controlling wind-induced vibration of mid- to high-rise wood and hybrid wood frame buildings, to ensure satisfactory vibration performance during high winds.
A literature review of the existing database of the dynamic properties of 1- to 3-storey wood platform buildings was conducted. The test system and protocols of ambient vibration tests (AVT) was developed. Collaboration with McGill University was also established to verify the AVT system and the test protocols. AVT tests were conducted on two 2-storey non-residential hybrid heavy timber platform buildings, three new heavy timber (glulam) non-residential buildings of 4-6 storeys and on two cross-laminated timber (CLT) condominium buildings of 3 and 4 storeys. The monitoring system to determine the vibration response in wind of mid-to high-rise wood frame building was developed. The database consisting of the data in the literature and our measured fundamental natural frequencies of the wood frame building were used to verify the NBCC equations to estimate building fundamental natural frequencies. Collaboration with Tongji University was established to explore the potential use of the finite element commercial software Ansys, for simulation of vibration performance of wood frame buildings.
It is concluded that the project was on the right track towards the development of a design guide for controlling wind-induced vibrations of mid- to high-rise wood frame buildings. The results from this study and other two relevant projects confirmed that AVT and computer simulation are useful, and appropriate tools for the development of solutions and a design guide for controlling wood frame building vibrations in wind.
It is recommended that current NBCC equations using building height as a variable to estimate the building fundamental natural frequency can be used to predict the fundamental natural frequencies of wood frame buildings, until a better calculation methodology is developed. More field data of the fundamental natural frequencies measured on mid- to high-rise wood frame or hybrid wood buildings are needed to further verify the NBCC equations, or to develop more suitable equations for wood buildings.