Grouted Rebar Coupler With Spring-Biased Stops for Seismic Anchoring
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Solution Overview
Problem
Existing couplers for splicing steel reinforcement bars in concrete members fail to reliably anchor the bars together, especially under seismic forces, leading to potential separation and shifting.
Innovation Solution
A coupler with spring-biased grout removal stops and a grout receiving chamber that anchors the rebars with a cementitious bonding material, ensuring they remain aligned and secured during earthquakes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a coupler is used to splice rebars in concrete members, then the rebars can be connected end-to-end, but the rebars may still be pulled out and separated under tensile loads such as seismic forces
Solution Approach 1:
Grout is introduced as an intermediary bonding material that fills the chamber surrounding the upset heads of the rebars. This grout creates a cementitious bond between the metal rebars and the coupler, providing reliable anchoring that prevents pullout under tensile loads while maintaining the mechanical connection structure.
Solution Approach 2:
The coupler system combines multiple materials with different properties: the metal coupler provides structural strength and geometry control, the steel rebars provide tensile strength, and the cementitious grout provides bonding and anchoring. This composite material approach creates a unified system where each material contributes its superior properties to achieve reliable rebar connection.
2Reliability
If grout is pumped into the chamber to anchor the upset heads, then the rebars are securely bonded, but the grout may flow outward and need to be contained
Solution Approach 1:
The grout containment features (such as grout stops or restricted outlet structures) are pre-formed as integral parts of the coupler structure before grouting occurs. This preliminary action prevents grout from flowing outward during the grouting process, containing it within the chamber where it can effectively bond the rebars without creating messy overflow or requiring additional containment measures.
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 coupler effectively prevents separation of rebars by anchoring them with a hardened bonding material, enhancing the seismic resistance and stability of concrete structures.
Implementation Method 1
A pair of spring-biased grout removal stops are hingedly connected to each of the first and second coupling cavities of the sleeve of the coupler
Implementation Method 2
When the bonding material dries and hardens, the upset heads will be anchored in place within the grout filled chamber
Data Source
AI summary
Disclosed is a grouted coupler for splicing together a pair of steel reinforcement bars (i.e., rebars) that are embedded within first and second concrete members to be connected together. In one embodiment, the first rebar is connected to a first coupling cavity of the coupler within the first concrete member. A wide upset head of the second rebar that stands upwardly from the second concrete member moves through a second coupling cavity of the coupler and into a grout receiving chamber when the first concrete member is moved towards the second concrete member. The second rebar is connected to the coupler when grout is pumped into the grout receiving chamber to surround and anchor the upset head of the second rebar. A spring-biased grout removal stop is positioned within the second coupling cavity to impede the free flow of grout outwardly from the grout filled chamber.