Behavior and Strength Characteristics of Cross-Laminated Timber Mats: Experimental and Numerical Study

Cross-laminated timber (CLT) is an innovative wood product that has been introduced recently to engineering practice; CLT members have a wide variety of applications in engineering practice, these include primarily building and architectural applications as structural members that support gravity and lateral load. Although CLT practices have been gaining popularity in building applications, this research explores new applications and focuses on investigating the CLT members for Industrial applications which include, crane mats, access mats, temporary bridges etc. The authors have established an experimental program to obtain strength parameters of CLT members built from Southern Yellow Pine members to help engineers design such members for the applications mentioned above. The experimental program consists of testing 10-15 in. x 216 in. x 5 layers of 2x8 members’ specimens in bending (Group 1), and 10-15 in. x 53 in x 5 layers of 2x8 members specimens in shear (Group 2), 10-48 in. x 216 in. x 5 layers of 2x8 members specimens in bending (Group 3) and 10-48 in. x 53 in. x 5 layers of 2x8 members specimens in bending (Group 4). The test dimensions were selected per ANSI PRG-320-2012 and were performed at the Forest Product Laboratory in Madison, WI. The specimens were tested to failure and load deflection curves were obtained. The test clearly identified the behavior of the CLT members up to failure as well as their failure modes. Additionally, non-linear finite element analysis was performed for the different tests to help validate the tests and understand the behavior of the CLT members. The results from the experimental program and from the finite element analysis were used to obtain the bending and shear strength parameters for CLT members and recommendations have been made to design such members. The methodologies used in this analysis and the failure modes observed in the laboratory provide behavioral characteristics of CLT’s that can be applied to the design of CLT’s for buildings.