Composite Deck Fastener Dual-Hardness Shear Transfer
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Solution Overview
Problem
Existing fastening methods for composite decking, such as weld studs, require additional operations like ceramic insulator removal and damage the decking material, and are limited by minimum steel thickness requirements, while direct fastening fasteners lack ductility to effectively transfer shear forces.
Innovation Solution
A direct fastening fastener with a dual-hardness level, where the insertion member is heat-treated to a high hardness for driving into steel and the remaining portion remains ductile to transmit shear forces, featuring an integral flange for concrete interlocking and a second flange to limit steel joist deflection, allowing for powered tool installation without deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If weld studs are used to secure decking to steel members, then the decking can be attached to the support member, but the process requires ceramic insulator removal which damages the decking and scatters ceramic pieces
Solution Approach 1:
The patent removes the ceramic insulator component entirely from the fastening system, replacing it with a direct fastening mechanism that achieves both attachment and concrete encasement without the need for insulator removal, thereby eliminating decking damage and ceramic scattering
Solution Approach 2:
The patent introduces a metal insulator or coating layer as an intermediary between the weld stud and decking, which protects the decking from direct contact with the stud while still allowing for effective attachment and concrete encasement
2Reliability
If weld studs with high heat are used to attach to steel members, then the stud can be welded to the support member, but the protective deck coating on the stud is damaged rendering it susceptible to corrosion
Solution Approach 1:
The patent applies protective coating to the weld stud before the welding process, and the welding procedure is designed to minimize heat exposure time, thereby protecting the coating from damage while still achieving reliable weld attachment
Solution Approach 2:
The patent modifies welding parameters such as heat input, welding speed, and technique to reduce thermal exposure, thereby preserving the protective coating on the stud while maintaining adequate weld strength
3Productivity
If direct fastening fasteners are heat treated to high hardness for driving into steel, then the fastener can be installed without additional operations, but the fastener loses ductility needed to transfer shear forces
Solution Approach 1:
The patent applies heat treatment selectively to specific portions of the fastener, such as the tip or driving end, to achieve high hardness for installation while leaving other portions with lower hardness to maintain ductility for shear force transfer
Solution Approach 2:
The patent employs fasteners with composite material structures or graded properties, combining hard heat-treated zones for installation with softer, more ductile zones for shear resistance, effectively merging the benefits of both material properties
4Strength
If weld studs are used with standard diameter, then the stud can provide adequate strength, but the minimum steel thickness required limits use in thin-gauge steel construction
Solution Approach 1:
The patent concentrates the fastener's engagement features and strength-providing elements at localized positions, allowing adequate structural strength to be achieved with smaller overall fastener dimensions that can penetrate thinner steel members
Solution Approach 2:
The patent reduces the diameter and overall dimensions of the fastener while compensating for strength through optimized geometry, material selection, or heat treatment, enabling use in thin-gauge steel construction where standard weld studs cannot be applied
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
Enables secure attachment of composite decking to steel members with enhanced shear force resistance and interlocking, reducing construction time and eliminating the need for additional operations like ceramic insulator removal, while accommodating thinner steel structures.
Implementation Method 1
At least a portion of the insertion member can be heat treated to enable the tip portion to drive into a decking member
Implementation Method 2
the remaining portion remains ductile to transmit shear forces
Data Source
AI summary
A direct fastening fastener particularly suited for use in normal weight or lightweight composite deck system. The fastener is heat treated to a dual-hardness level so that a portion of the fastener is capable of driving into the support member, such as a joist and a decking member. The remaining portion of the fastener remains relatively ductile so that it can withstand and transfer shear loads imposed by shifting of the concrete slab, which overlies the composite decking, to the support member. The fastener can be a single or multiple piece fastener which includes specially formed annular flanges that enhance interlocking between the fastener, the concrete slab and support members.