The use of wood in the construction of mid- and high-rise buildings is proving to be a competitive alternative to steel and concrete. However, like any other building material and system, wood systems must comply with the rules of building codes and thereby ensure users’ comfort with respect to sound transmission and building vibration.
This session on acoustic and vibration performance will be an opportunity to review recent advances in these fields and share views and experiences with international experts in the field.
Discussions will inevitably take place on how to translate research findings into effective, sustainable technical solutions.
Moderator : Jean-Luc Kouyoumji, FCBA, France
Special in acoustic modelling of mass timber
Speaker: Delphine Bard, Lund University, Sweden
Wood is increasingly used as a structural material in buildings, improving the conditions for a circular economic cycle within the construction sector. However, structural wood still creates doubts among many developers. One issue is the difficulty to easily meet the soundproofing insulation requirements in comparison with concrete construction. The design of wood buildings requires specific knowledge; depending on the system, they are sensitive to failure during the construction phase. Nevertheless, it is possible to erect wood buildings with high acoustic performance; it is just a matter of knowledge and awareness of where to put the priority. However, the acoustic challenges increase with taller buildings. It is the duty of acousticians to ensure that the requirements mandated in the design process truly correspond to mitigating the potential problems for inhabitants. Increased knowledge is necessary, in particular regarding different housing categories. In wood building design, current building requirements must be scrutinized and adapted in order to:
- avoid low frequencies causing high noise levels in specific cases
- minimize the risk of annoying vibrations
- optimize construction to allow a certain amount of flanking transmission, without causing irritation
- adapt to new building categories and future apartment sizes.
New generation of walls and floors, with visible wood, using CLT and LVL, measurements and predictions
Speaker: Jean-Luc Kouyoumji, FCBA, France
In many jurisdictions, acoustic requirements are as strictly enforced as those for structural sufficiency and fire safety. Adequate levels of noise control in multi-family buildings are mandatory requirements of building codes in Europe. Also, since 2018, quality construction labels include low frequency behaviour, starting from 50 Hz. Much effort has been spent on the evaluation of sound transmission (Rw) and impact sound level (Lnw) of floor and wall assemblies, and on studies of flanking transmission in multi-family dwellings. However, architects are challenging acoustic design with visible wood in construction: visible wood as a ceiling or a wall. This presentation will focus on laminate veneer lumber (LVL) and cross-laminated timber (CLT) floors and walls capable of performing well acoustically, in residential, multi-residential and non-residential buildings. Design, prediction and test results will be presented.
Title to be confirmed
Speaker: Jeffrey Mahn, NRC, Canada
Vibro-Acoustic Behaviour of Wooden Buildings in Low-Frequency Range
Speaker: Cheng Quian
The market share of wooden construction has been steadily increasing in recent years with the development of wood science. However, wooden construction is still more vulnerable to sound insulation issues, especially low-frequency noise, compared to heavy construction, despite it having fulfilled the requirements of current sound insulation standards.
The project presented here focuses on the development of numerical models to predict the impact of sound insulation performance of a CLT-concrete floor in low-frequency range. The study begins with modelling dynamic behaviour of the ISO standardized tapping machine, then by investigating the dynamic response of the CLT base floor. The stochastic method is proposed to calibrate the wooden structures. The vibro-acoustic performance of the CLT-concrete floor is studied, and the prediction method of this type of floor is developed at the final stage of this project. The proposed modelling methods can ultimately serve as acoustic guidelines before buildings are erected and, subsequently, decrease conception time and costs.
Jean-Luc Kouyoumji has been a research engineer since 1997 at the Technological Institute FCBA (Institut Technologique Forêt Cellulose Bois-construction Ameublement). He has a PhD in Civil engineering and Building Sciences from Université Savoie. He has been project manager or coordinator for over 30 R&D projects (both private and public) and has written over 25 papers on acoustics and building energy for international congresses and scientific reviews. His areas of expertise are: (1) Improvement and modelling of acoustic performance of wooden buildings and flanking transmissions; (2) Biosourced materials for energy-efficient buildings; (3) Technology transfer of, and innovations in, construction; (4) International cooperation among researchers, engineers, technical centres and construction companies. Dr. Kouyoumji has chaired 15 sessions on acoustics lightweight constructions for the Internoise and ICA Acoustics congresses. He has been vice-chair of the EU-COST Action FP0702, and TAIEX expert for MED Mediterranean countries. He is the co-Author of the Cross Laminated Timber Handbook for Canada and reviewer of the Technical Guide for the Design and Construction of high-rise Wood Buildings in Canada and for the CLT Handbook USA.
Delphine Bard is a researcher and associate professor at Engineering Acoustics, Lund University in Sweden. She is responsible for the acoustic research group at Lund, which she has been developing over the past 8-10 years, with strong focuses on timber structures and modelling with regard to the Finite Element Method (FEM). The group has a full array of laboratories for building acoustic research and measurements, available for acoustic testing and development for industrial applications/products. Additionally, she teaches acoustics to students and leads and/or participates in a number of projects financed through the industry, national funding institutions and European funding. Ms. Bard also works part-time within the global material company group, Saint-Gobain, as an expert in acoustics, providing knowledge and support mainly for the Nordic market.
Jeffrey Mahn is a senior research officer at the National Research Council of Canada, specializing in flanking sound transmission in buildings. The NRC is currently engaged in large-scale research projects relating to the transmission of structure-borne noise in mid-rise wood and mass timber buildings. Based on the results of the projects, the NRC has published a number of research reports to support the transition to the acoustic requirements in the National Building Code of Canada including the recently published fourth edition of RR-331 Guide to Calculating Airborne Sound Transmission in Buildings, and the second edition of RR-335 Apparent Sound Insulation in Mass Timber Buildings.
Qian Cheng is a PhD student who works on acoustic insulation of wooden constructions at University of Québec in Chicoutimi.
He chose acoustics as a major during bachelor’s and master’s studies in France. From these 5 years education, I learned that sound can not only influence our physical body condition but also our psycho-mental condition. He continued studies as a PhD student in Canada, working as researcher both in Canada and in Sweden, focusing on the development of prediction tools for wood construction, and also guided a master’s student project at Lund University.
All the experience in acoustics these years makes him passionate about resolving the acoustic insulation issues for wooden buildings and to eventually achieve high-quality acoustic comfort in multi-family wooden constructions.