Mass Timber Hanger Structure for Fire-Rated Wall Connections
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Solution Overview
Problem
Current fire resistance rated wall systems in building construction struggle to simultaneously provide fire resistance and structural load-bearing capabilities, especially when integrating mass timber panels, due to conflicts between continuity requirements and the need to support structural loads.
Innovation Solution
A mass timber hanger device with a plurality of legs, including a first leg for attachment to a horizontal structural panel, a second leg for attachment to structural members within a wall, and a third leg that maintains a predetermined distance between the first and second legs, allowing protective sheathing panels to interpose between the mass timber panel and the wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gypsum wallboard is used to protect wall studs from fire, then fire resistance is improved, but structural load-bearing capability deteriorates because gypsum has very little bearing strength and cannot transfer robust structural loads
Solution Approach 1:
The invention divides the wall assembly into separate functional components: the gypsum wallboard serves solely as fire protection, while the mass timber panel and hanger system provide structural load-bearing capability. This segmentation allows each component to optimize its specific function without compromising the other.
Solution Approach 2:
The hanger acts as an intermediary element that transfers structural loads from the mass timber panel to the wall studs, bypassing the gypsum wallboard. This mediator enables the load path to avoid the weak gypsum layer while maintaining fire protection integrity.
2Reliability
If fire resistance rated walls are made continuous from foundation to roof, then fire safety is improved, but adaptability to support mass timber floors and roofs deteriorates due to continuity requirements limiting structural integration
Solution Approach 1:
The hanger system provides multiple functions: it supports mass timber structural panels, maintains fire resistance rating continuity, and enables integration between fire-rated walls and mass timber floors/roofs. This multi-functionality resolves the conflict between fire safety continuity and structural adaptability.
Solution Approach 2:
The invention introduces a new dimensional approach by extending the hanger through the gypsum wallboard layer, creating a three-dimensional load path that bypasses the fire protection layer while maintaining its integrity. This dimensional change allows simultaneous achievement of fire continuity and structural support.
3Strength
If the hanger extends through the protective sheathing, then structural load transfer is improved, but fire resistance continuity deteriorates because the hanger penetrates the fire protection layer
Solution Approach 1:
The hanger extracts the load transfer function from the fire protection assembly by penetrating the gypsum wallboard. This extraction allows the structural function to be separated from the fire protection function, with the hanger carrying loads through the gypsum layer without compromising its fire resistance integrity.
Solution Approach 2:
The hanger serves as a mediator that passes through the gypsum wallboard, allowing structural loads to be transferred while the gypsum layer maintains its fire protection continuity. The penetration is designed to preserve the fire rating by maintaining the integrity of the fire protection assembly around the hanger.
Data Source
AI summary
A structural hanger providing a means for connecting a horizontal or sloped mass timber panel to a wall with sheathing without impairing the fire resistance rating of the wall. One embodiment comprises a plurality of legs, including a first leg with a means for connecting the hanger to a mass timber panel, a second leg with a means for connecting the hanger to structural members within the wall, and a third leg connecting the first and second leg to each other and extending through the sheathing mounted to the wall.