Wood-concrete composite slab floors provide a promising solution for achieving long spans and shallow wood-based floor systems for large and tall wood buildings. In comparison with conventional wood floor systems, such long span and heavy floors have a lower fundamental natural frequency, which challenges the floor vibration controlled design. A laboratory study, including subjective evaluation and measurement of the natural frequencies and one-kN static deflections, was conducted on wood-concrete composite floors. Method of calculation of the composite bending stiffness of the wood-concrete composite floor is proposed. The design criterion for human comfort was derived from the subjective evaluation results using the calculated fundamental natural frequency and 1 kN static deflection of one meter wide strip of the composite floor. The equation to directly determine the vibration controlled spans from the stiffness and mass was derived. Limited verification was performed. Further verification is needed when more field wood-concrete composite floors become available.
This guide provides the directives needed for designers of tall wood buildings to produce their designs, plans and specifications. It has been developed to give them the information and general concepts required, based on the selected system. The elements and details required to comply with the guidelines in this document must be incorporated from a project’s initial design phase.
Part 1 – Guidelines contains several sections, including one that deals with basic conditions and describes the minimum general conditions applicable to any project for the construction of a wood building exceeding 6 storeys. The following sections contain special provisions that specify and complete the basic conditions.
Several analytical and empirical methods have been developed and adopted in Europe for the determination of shear and bending properties of Cross-laminated Timber (CLT) elements loaded out-of-plane and in-plane. However, proposed evaluation methods for determining in-plane shear strength in CLT elements acting as deep beam or lintels need to be verified on Canadian CLT products. This paper presents results from recent testing program following established ASTM standard methods for evaluating the in-plane shear strength of CLT elements for beam applications. Results indicate that the existing test method applicable to Structural Composite Lumber (SCL) may be suitable for the evaluation of in-plane shear strength of CLT elements.
Cross-laminated timber (CLT), a new generation of engineered wood product developed initially in Europe, has been gaining popularity in residential and non-residential applications in several countries. Numerous impressive low- and mid-rise buildings built around the world using CLT showcase the many advantages that this product can offer to the construction sector. This article provides basic information on the various attributes of CLT as a product and as structural system in general, and examples of buildings made of CLT panels. A road map for codes and standards implementation of CLT in North America is included, along with an indication of some of the obstacles that can be expected.
Cross-laminated timber (CLT) is a prefabricated solid engineered wood product made of at least three orthogonally bonded layers of solid-sawn lumber or structural composite lumber that are laminated by gluing of longitudinal and transverse layers with structural adhesives to form a solid rectangular-shaped, straight, and plane timber intended for roof, floor, or wall applications. While this engineered wood product has been used in Europe for over 15 years, the production of CLT and design of CLT structural systems have just begun in North America. For the acceptance of new construction materials or systems in North America, such as CLT, a consensus-based product standard is essential to the designers and regulatory bodies. This paper describes and documents the background information and some key issues that were considered during the development of the ANSI/APA PRG 320 Standard for Performance-Rated Cross Laminated Timber. This standard was developed based on the consensus standard development process of APA-The Engineered Wood Association as a standards developer accredited by the American National Standards lnstitute (ANSI). The CLT stress classes incorporated in this product standard are also discussed. The ANSI/APA PRG 320 standard has been approved by the Structural Committee of the lnternational Code Council (lCC) for the 20'15 lnternational Building Code (lBC).
