Description

Designers need to show that heavy timber buildings maintain their stability during and after a fire. A joint research project has initial findings on the fire performance of mass timber construction joints to help.

Timber is increasing in popularity as the primary structural material for multi-storey buildings. Key drivers for choosing it include:

• poor soils, where lighter structures reduce foundation requirements
• adding floors, where a lighter material reduces the load from additions to an existing structure
• prefabrication for faster construction of the primary structure
• meeting sustainability and green building objectives.

Timber’s increased use has been enabled by engineered wood products such as laminated veneer lumber (LVL), glulam and cross-laminated timber (CLT), which have overcome some of the limitations of sawn lumber. These products have more consistent material properties, greater strengths, larger element dimensions and the opportunity for extensive prefabrication.

Scope

This article includes:

• Structural performance in fire
• Connections can be the hot point
• Research into connections performance
• Three key preliminary findings
  • Charring results in deformations that can impair connection performance
  • Connection performance and failure mechanisms are different to those at ambient temperatures
  • The thermal wave continues to propagate through the member during the decay phase
• Designing timber connections