Splice Connections with Higher Strength than the Base Metal

Request Number REQ3293824
Due Date September 30, 2015
Author Nick Kacsandi
Request for Proposal Details
RFP Title
Splice Connections with Higher Strength than the Base Metal
RFP Description

NineSigma, representing a leading supplier of non-residential construction products, invites proposals for technologies capable of achieving a tension and compression splice that prevents failure in reinforcing rebar to a distance of two (2) bar diameters from the connection point.


In most structural applications, the steel rebar cages that provide necessary reinforcement are comprised of dozens or hundreds of individual connection points. Regulatory requirements (e.g. California CT270, etc.) dictate that in a failure scenario these connection points – or splices – between individual rebar components cannot be the ultimate failure point, and must be able to survive cyclic tension and compression loads. Furthermore, the point of failure must occur remotely from the connection, at least two (2) bar diameters from the end of the splice.


A variety of innovative approaches are currently employed to address this requirement, including clamping or compression mechanisms, threaded connections, lap splicing, and grout-filled sleeve fittings. However, the current solutions are not universally applicable due to variability in the installation requirements from application to application. The RFP sponsor seeks potential partners with novel approaches or technologies that can create a universally reliable connection that supersedes the strength of the structural rebar in the end application. Approaches that promote similar performance and failure characteristics at the rebar-end anchor connection point (as opposed to the rebar-rebar connection) are also of significant interest.


Solutions are invited from across the landscape of industry, research and academia. Of specific interest are those cross-industrial technologies that can be reapplied from similar applications involving connections of other steel components, non-ferrous metal components, high strength composites and other materials.


Anticipated Project Phases or Project Plan

Phase 1 – Initial discussions under NDA to determine validity of approach


Phase 2 – Proof of technical concept against RFP specifications

  • Technical data or report for evaluation
  • Samples or prototypes provided for client testing
  • Cost / pricing estimates


Phase 3 – Commercial development

  • Development pathway including plan for optimizing against key success criteria


Key Success Criteria

The successful technology will:

  • Be compatible with or adaptable to steel rebar that will eventually be embedded in cured concrete.
  • Be compatible with steel substrates with one or more of the following characteristics:
    • Uncoated steel alloy
    • Stainless steel
    • Galvanized steel
    • Steel with epoxy coating up to 12 to 16-mm in thickness
  • Create a connection that exceeds the ultimate strength of the 105 ksi grade rebar.
  • Reinforce the rebar at and around the connection such that failure always occurs at least two (2) bar diameters from the terminal connection point.
    • Minimum Bar Diameter: 0.375-inches (#3 rebar)
    • Maximum Bar Diameter: 2.5-inches (#20 rebar)


The final qualification testing for the strength and efficacy of any proposed solution following proof of concept must meet the client’s requirements as a free-standing system without the benefit of being embedded in concrete.



Possible Approaches

Possible approaches might include, but are not limited to:

  • Novel clamping technologies
  • Advanced threading approaches
  • Design-based approaches to optimize strength at the connection point
  • Novel material joining and fusion technologies
    • Adhesives
    • Solid State Joining
    • Diffusion Bonding
    • Bio-welding
  • Approaches, materials or coatings that also increase the overall strength of steel in cured concrete
  • Approaches from other industries that may be adapted to meet the criteria of this application.
  • Approaches currently employed on non-steel substrates that may be adapted to meet the criteria of this application


Approaches not of interest

The following approaches are not of interest:

  • Traditional welding or joining technologies that do not improve upon current industry standards
  • Solutions achieve the end requirements but that detrimentally impact the overall strength of the rebar, either locally or remote from the connection site.
  • Theoretical solutions that are not supported by development and optimization capabilities
  • Failure modeling approaches that are not supported by additional development capabilities


Preferred Collaboration types
Items to be submitted

To respond, please make sure you are registered in NineSights, as it will prompt you to log in. Then, use the Response options at the top or bottom of the page. You may submit supplemental files in addition to your completed response form.


Appropriate responses will use the response form and address the following:

  • Non-confidential description of proposed technology
  • Technical maturity of the approach (concept, prototype, ready to commercialize, commercialized)
  • Compatibility of the proposed solution with the requirements outlined in the “Key Success Criteria” section above.
    • If proposing an approach from an adjacent industry, please provide justification for how your technology would meet the desired results for the given application.
    • If proposing an approach currently employed on materials other than steel, please provide justification for how your technology could be optimized for use on steel.
    • Discussion of how to resolve unmet Success Criteria.
  • Performance data, if available and applicable
  • Budget / Cost information, if available
  • Team / Organization description
  • Relevant expertise, experience or background related to the RFP topic area
  • Desired relationship with the RFP sponsor
  • Position on handling or negotiation intellectual property rights (if applicable)


Area of Interest
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