Concrete Connectors for Fire-Resistant Mass Timber Joining
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Solution Overview
Problem
Existing metal connectors for mass timber structures are expensive, susceptible to fire damage, and require tight installation tolerances, necessitating additional fire protection and multiple hangers for beam-column connections.
Innovation Solution
A fire-resistant concrete connector, referred to as a 'Timber Concrete Node' (TCN), which can be precast or cast onsite, incorporates void channels for fasteners and offers modular designs to securely join timber components, eliminating the need for metal connectors and ensuring structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal hangers are used to connect timber structural components, then the connection capacity is high, but the connector is susceptible to fire damage and requires supplemental fire protection
Solution Approach 1:
The patent changes the material parameter from metal to concrete, fundamentally altering the fire resistance characteristic while maintaining structural connection capability. Concrete inherently resists fire without supplemental protection, eliminating the need for fire-rated coatings or sacrificial timber covers required by metal hangers.
Solution Approach 2:
The connector uses reinforced concrete, a composite material combining concrete's fire resistance with steel reinforcement's tensile strength. This composite approach maintains high connection capacity while achieving inherent fire resistance, as the concrete protects the reinforcement from fire damage.
2Strength
If metal hangers are used for timber connections, then the connection strength is sufficient, but the installation requires tight tolerances and multiple hangers for beam-column connections
Solution Approach 1:
The connector incorporates void channels segmented throughout the concrete body, allowing fasteners to be installed at multiple discrete locations. This segmentation provides flexibility in installation, eliminating the need for tight tolerances while achieving sufficient connection strength through distributed fastening.
Solution Approach 2:
The concrete connector serves multiple functions: it provides structural connection strength, accommodates various fastener types through void channels, and offers fire protection. The void channels can accommodate different fastener configurations, making the connector universally applicable to various timber connection scenarios without requiring precise tolerance control.
3Strength
If metal connectors are used for mass timber structures, then the connection capability is achieved, but the cost is high and additional fire protection is required
Solution Approach 1:
The patent replaces expensive metal connectors with concrete connectors that eliminate the need for costly supplemental fire protection systems. While concrete is not inherently stronger than metal, it eliminates additional costs for fire-rated coatings, sacrificial timber covers, or specialized metal fire-resistant connectors, providing a more cost-effective solution overall.
4Object-affected harmful factors
If concrete is used for the connector, then fire resistance is improved, but the weight increases
Solution Approach 1:
The patent changes the material from metal to concrete, accepting the weight increase as a trade-off for inherent fire resistance. The concrete connector weighs more than metal but eliminates the need for supplemental fire protection, providing a simpler, more fire-resistant solution despite the weight penalty.
Data Source
AI summary
A structural connector for joining mass timber structural components is disclosed. The structural connector is made of a material comprising concrete. In some embodiments, the material comprises reinforced concrete. One or more mounting channels dimensioned for a fastener to insert there through may be defined within the concrete. The fastener may be configured to fixedly secure the connector to the timber structural components that are desired to be joined. In some embodiments, one or more reinforcing members are embedded in the concrete, which may be in addition to fiber reinforcing in the connector. The described connector may be used to join two or more of timber purlins, beams, columns, posts, walls, etc. to form a structural assembly.