The use of timber–concrete composite (TCC) bridges in the United States dates back to approximately 1924 when the first bridge was constructed. Since then a large number of bridges have been built, of which more than 1,400 remain in service. The oldest bridges still in service are now more than 84 years old and predominately consist of two different TCC systems. The first system is a slab-type system that includes a longitudinal nail-laminated deck composite with a concrete deck top layer. The second system is a stringer system that includes either sawn timber or glulam stringers supporting a concrete deck top layer. The records indicate that most of the TCC highway bridges were constructed during the period of 1930–1960. The study presented in this paper discusses the experience and per-formance of these bridge systems in the US. The analysis is based on a review of the relevant literature and databases complemented with field inspections conducted within various research projects. Along with this review, a historical overview of the codes and guidelines available for the design of TCC bridges in the US is also included. The analysis undertaken showed that TCC bridges are an effective and durable design alternative for highway bridges once they have shown a high performance level, in some situations after more than 80 years in service with a low maintenance level.
Project contact is Erol Karacabeyli at FPInnovations
To support NRCan's Tall Wood Building Demonstration Initiative, FPInnovations developed and published the 2014 Edition of Technical Guide for the Design and Construction of Tall Wood Buildings in Canada. More than 80 technical professionals comprised of design consultants and experts from FPInnovations, the National Research Council, the Canadian Wood Council and universities were involved in its development. The Guide has gained national and worldwide reputation as one of the most complete and credible documents helping to introduce to the design and construction community, and Authorities Having Jurisdiction the terms "Mass Timber Construction" and "Hybrid Tall Wood Buildings".
Since the publication of the First Edition, a number of tall wood buildings have been designed and constructed. Substantial regulatory changes are expected to happen based on the experience obtained from the demonstration initiative and the extensive research that has taken place domestically and internationally since the publication of the First Edition. These developments highlight a need for the Guide to be updated so that it aligns with efforts currently underway nationally and provincially and continues to lead in providing the design and construction community technical insight into new opportunities for building in wood.
The First Edition of the Guide helped to focus the efforts of the early adopters who participated in NRCan's Tall Wood Building Demonstration Initiative. Updating and aligning the Guide with the release of the new National Building Code of Canada and the Canadian wood design standard (CSA O86), and sharing the experiences gained from tall wood buildings built since the First Edition, will not only continue to expand the base of early adopters, but also help to move aspects of mass timber and hybrid wood buildings into the mainstream.
Strength parameters for fasteners determined in accordance with the methods prescribed for the European CE-marking leads to quite different values for seemingly similar products from different manufactures. The results are hardly repeatable, to some extent due to difficulties in selecting representative on engineered wood products...
Project contact is Jianhui Zhou at the University of Northern British Columbia
Building acoustics has been identified as one of the key subjects for the success of mass timber in the multi-storey building markets. The project will investigate the acoustical performance of mass timber panels produced in British Columbia. The apparent sound transmission class (ASTC) and impact insulation class (AIIC) of bare mass timber elements as wall and/ or floor elements will be measured through a lab mock-up. It is expected that a database of the sound insulation performance of British Columbia mass timber products will be developed with guidance on optimal acoustical treatments to achieve different levels of performance.
The growing diffusion of cross-laminated timber structures (CLT) has been accompanied by extensive research on the peculiar characteristics of this construction system, mainly concerning its economic and environmental benefits, lifecycle, structural design, resistance to seismic actions, fire protection, and energy efficiency. Nevertheless, some aspects have not yet been fully analysed. These include both the knowledge of noise protection that CLT systems are able to offer in relation to the possible applications and combinations of building elements, and the definition of calculation methods necessary to support the acoustic design. This review focuses on the main acoustic features of CLT systems and investigate on the results of the most relevant research aimed to provide key information on the application of acoustic modelling in CLT buildings. The vibro-acoustic behaviour of the basic component of this system and their interaction through the joints has been addressed, as well as the possible ways to manage acoustic information for calculation accuracy improvement by calibration with data from on-site measurements during the construction phase. This study further suggests the opportunity to improve measurement standards with specific reference curves for the bare CLT building elements, in order to compare different acoustic linings and assemblies on the same base. In addition, this study allows to identify some topics in the literature that are not yet fully clarified, providing some insights on possible future developments in research and for the optimization of these products.