Infilled CLT Wall Frame With Suspended Panel for Lateral Loads
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Solution Overview
Problem
Traditional cross-laminated timber (CLT) panels and precast concrete panels in buildings are prone to failure due to rocking mechanisms at connections, limiting their use to low-rise structures, and there is a need for safe mechanisms under lateral loadings in mid-rise and high-rise constructions.
Innovation Solution
A wall system with a frame, suspended-infilled CLT panel, and steel angles connected by fasteners, allowing the panel to rotate and translate within the frame, dissipating energy through bending and deformation of fasteners, thereby reducing the risk of rocking and enabling safer construction in mid-rise and high-rise buildings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional CLT panels are used with angle brackets or connections at lower corners, then the panel can be held down to structural members, but the panel develops a rocking mechanism under lateral loadings that can cause failure and collapse
Solution Approach 1:
The patent transitions from a static rigid connection system to a dynamic system where the CLT panel can rotate and translate within the frame. The panel is suspended by steel angles connected to beams, allowing controlled movement that dissipates energy through fastener bending and deformation, preventing catastrophic rocking failure
Solution Approach 2:
The patent changes the connection parameters by introducing gaps between the panel and frame members, and by using fasteners with specific bending characteristics. The steel angles and fasteners are designed to deform elastically and plastically under lateral loads, changing the mechanical behavior from rigid to ductile
2Stability of the object's composition
If rigid panels like CLT or precast concrete are used in walls, then the panels provide lateral stability, but they are limited to low-rise buildings due to the rocking mechanism and potential for disastrous failure
Solution Approach 1:
The patent enables rigid panels to be used in mid-rise and high-rise buildings by making the connection system dynamic. The panel can rotate and translate within the frame, allowing the wall system to accommodate lateral deformations in taller structures without developing catastrophic rocking mechanisms
Solution Approach 2:
The patent introduces steel angles and fasteners as intermediary elements between the rigid CLT panel and the frame. These intermediaries absorb and dissipate energy through bending and deformation, protecting the rigid panel from direct stress concentrations that would limit building height
3Strength
If the CLT panel is directly connected to the frame members, then the connection is rigid, but the panel cannot rotate or translate which causes stress concentrations and potential failure
Solution Approach 1:
The patent segments the connection system into multiple components: steel angles attached to frame members, fasteners connecting angles to the panel, and intentional gaps between panel edges and frame. This segmentation allows each component to perform its function - the angles provide attachment points, fasteners allow controlled deformation, and gaps enable rotation and translation
Solution Approach 2:
The steel angles act as intermediary elements that distribute loads from the panel to the frame members. The fasteners serve as intermediaries that allow controlled bending and deformation, dissipating energy and reducing stress concentrations on the rigid panel
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides a ductile shear mechanism that minimizes damage during earthquakes and hurricanes, enabling the use of rigid panels in taller buildings by absorbing energy through fastener deformation.
Implementation Method 1
The fasteners connected through steel members between the frame and the CLT panel bend and deform under the loadings. The bending and deformation of the fasteners dissipate energy during the racking behavior of the frame.
Data Source
AI summary
A wall system with two columns, two beams, one infilled cross-laminated timber panel, steel angles and associated fasteners, is presented. The columns and beams form four sides of a planar frame. Each of the columns and the beams is configured to connect to a steel member with fasteners protruding inside of the planar frame to receive the infilled cross-laminated timber panel. The steel member connects to the panel with at least one fastener. Each edge of the panel is configured to have a space from the inside face of the frame, leaving an all-around gap between the panel and the surrounding frame members. The infilled panel is essentially suspended inside the frame by the steel member and their associated fasteners. The gap between the frame and the infilled panel allows the panel to rotate and translate when the frame deforms to a parallelogram shape under lateral loadings.