Concrete Form Tie Assembly for Masonry Stem Walls
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Solution Overview
Problem
Existing construction methods for monolithic concrete floor slabs supported by masonry stem walls face instability and increased complexity due to inadequate bracket members and the need for non-standard notching of header blocks, leading to inefficiencies and higher costs.
Innovation Solution
A tie assembly comprising a retaining member, extension member, and slotted tab member with a release mechanism, which allows for secure bracing of concrete forms without requiring non-standard notching or alterations to the header blocks or stem walls, using a wedge stake to resist lateral forces and mechanical fasteners for reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If standard masonry blocks are used without notching, then construction is simpler and faster, but the forms cannot be positioned in co-planar orientation with the stem wall exterior face
Solution Approach 1:
The patent introduces a tie assembly as an intermediary component between the standard masonry block and the concrete form. The tie assembly includes a retaining member with a bend that hooks under the header block, an extension member that spans across the block, and a tab member that extends beyond the stem wall face to support the form. This intermediary device enables co-planar form positioning without requiring modification of the standard masonry blocks.
2Manufacturing precision
If notched header blocks are used to achieve co-planar form orientation, then form positioning accuracy improves, but construction complexity and time increase
Solution Approach 1:
Rather than modifying the header blocks themselves (notching), the patent uses a tie assembly as a mediator that attaches to the unmodified blocks and provides the necessary form support. The tie assembly's retaining member hooks under the header block, the extension member spans across it, and the tab member provides the cantilevered support needed for co-planar form orientation, thereby avoiding the complexity of notching operations.
Solution Approach 2:
The tie assembly is divided into distinct functional segments: the retaining member (with shank and bend) that anchors to the header block, the extension member that provides structural span, and the tab member that supports the form. This segmentation allows each component to perform its specific function independently while working together as a complete system.
3Strength
If bracket members are used to support forms, then form support is provided, but the forms cannot be positioned in substantially co-planar orientation with the stem wall exterior face
Solution Approach 1:
The tie assembly serves as an intermediary between the bracket member and the form. The retaining member and extension member provide the structural support function of the bracket, while the tab member extends beyond the stem wall face to provide the precise positioning needed for co-planar form orientation. This intermediary structure allows both strong support and accurate positioning to be achieved simultaneously.
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 tie assembly ensures a stable and efficient construction process by maintaining the forms in a co-planar orientation, reducing construction complexity and costs, while providing effective anchoring against pullout and uplift forces, and facilitating easy removal after concrete curing.
Implementation Method 1
The wedge stake is then inserted into the slot, and the wedging action causes the wedge stake to firmly brace the form member against the lateral forces caused by the wet concrete of the floor slab.
Implementation Method 2
The tab member comprises a slot configured to receive and removably retain a wedge stake, which braces the form member.
Implementation Method 3
A mechanical fastener is then driven through the wedge stake and through the form member to protrude from the interior face of the form member.
Implementation Method 4
The tabs are removed by striking the tabs with an impact force, which causes the tie assembly to fracture at the release mechanism.
Data Source
AI summary
A tie assembly for use during construction of monolithic cast-in-place concrete floor slabs bearing on a masonry stem wall. The tie assembly connects to one or more header blocks of the stem wall, and the tie assembly is configured to retain a concrete form member in place during the pour and curing period of the cast-in-place concrete. The tie assembly has a removable tab member with one or more slots for receiving a wedge stake, which braces the form member against lateral forces caused by the wet concrete. A mechanical fastener is driven through an upper portion of the wedge stake and concrete form, and the insertion tip of the mechanical fastener connects to a reinforcement holder for retaining a reinforcing member in place.