FPInnovations carried out a survey with consultants and researchers on the use of analytical models and software packages related to the analysis and design of mass timber buildings. The responses confirmed that a lack of suitable models and related information for material properties of timber connections was creating an impediment to the design and construction of this type of buildings. Furthermore, there is currently a lack of computer models and expertise for carrying out performance-based design for wood buildings, in particular seismic and/or fire performance design.
In this study, a sophisticated constitutive model for wood-based composite material under stress and temperature was developed. This constitutive model was programmed into a user-subroutine which can be added to most general-purpose finite element software. The developed model was validated with test results of a laminated veneer lumber (LVL) beam and glulam bolted connection under force and/or fire.
The work presented in this report is a continuation of the FPInnovations' research project on determining the performance of the CLT as a structural system under lateral loads. As currently there are no standardized methods for determining the resistance of CLT shearwalls under lateral loads, the design approaches are left at the descretion of the designers. The most common approach that is currently used in Europe and North America assumes that the resistance of CLT walls is a simple summary of the shear resistance of all connectors at the bottom of the wall. In this report some new analytical models for predicting the design (factored) resistance of CLT walls under lateral loads were developed based on connection properties. These new models were then evaluated for their consistency along with their models that are currently used in North America and in Europe.
The current study aims at evaluating the integrity failure (i.e. passage of hot gases or flames through the assembly) of CLT assemblies connected together using four types of commonly used panel-topanel joints when exposed to the standard CAN/ULC S101 “Standard Method of Fire Endurance Tests...
There is a need to demonstrate how novel timber-concrete composite floors can span long distances and be a practical alternative to other traditional structural systems. Better understanding of the fire behaviour of these hybrid systems is essential. To achieve this, the fire-resistance of a timber-concrete composite...
The intent of this project is to research evaluation and rehabilitation methods that are applicable to mass timber structures following a fire. This includes addressing both fire damage and water damage from sprinkler activation and/or the use of firefighting hoses. This report provides an overview of the type of damage that might be expected following a fire and methods that might reduce potential damage (including design elements and firefighting tactics). Current and existing rehabilitation methods for wood construction will be reviewed and their applicability to mass timber structures will be discussed. This includes the ability to conduct condition assessments and repairs on building elements that can be done in place. The overall objective is to reduce uncertainty related to mass timber construction, which ultimately would allow for more accurate risk evaluation by insurance companies.
This report summarizes basic wood-moisture relationships, and reviews conditions conducive to adverse consequences of wetting, such as staining, mold growth, decay, strength reduction, and dimensional change and distortion. It also outlines solutions and available resources related to on-site moisture management and design measures.
This Chapter focuses on a few fastening systems that reflect present-day practices, some being conventional, while others are proprietary. Given the recent introduction of CLT into the construction market, it is expected that new connection types will be developed over time. Issues associated with connection design specific to CLT assemblies are presented. The European design approach is also presented and the applicability of the National Design Specification (NDS) for Wood Construction design provisions for traditional fasteners in CLT such as bolts, dowels, nails, and wood screws are reviewed and design guidelines are provided. Several design examples are also given at the end to demonstrate how connections in CLT can be established using current NDS design provisions.
Cross-laminated timber (CLT) was developed in Europe for the prefabricated construction of wall, roof, and flooring elements. Adaption of CLT for use in the United States requires consideration of the different climates, building codes, and construction methods in this country. ... This Chapter provides guidance on hear, air, and moisture control in wall and roof assemblies that utilize CLT panels in U.S. climate zones. The overarching strategies are to prevent wetting of CLT panels by using drained wall systems, to control airflow using an air barrier on the exterior of the CLT panels, to place rigid insulation to the exterior of the panels, to prevent moisture from accumulating within the panels, and to allow the panels to dry should they get wet. In certain climates, preservative treatment of CLT is recommended to provide additional protection against potential hazards such as decay and termites. ...
To investigate the wetting and drying behaviour of the face and edge surfaces of cross-laminated timber (CLT), including edge-to-edge joints covered with plywood spline
To evaluate effectiveness of water-repellent coatings and membranes that are factory-applied with the intent to prevent wetting caused by rain, installation of wet light-weight concrete topping, or contact with damp concrete surfaces
To assess potential impact of fire protection measures including drywall and rigid mineral wood insulatio on the drying performance of wet CLT
To further develop practical solutions for on-site management of mass timber construction