Rebate Form Ferrule Support for Slip Form Casting

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Solution Overview

Problem

The existing slip form casting process for high-rise building central cores requires time-consuming bending and straightening of reinforcement, which reduces ductility and complicates the placement of reinforcement within rebates, leading to difficulties in ensuring ductility remains within prescribed limits.

Innovation Solution

A formwork system with a rebate form and ferrule supports that allows ferrules to be cast into the core, eliminating the need for bending and straightening reinforcement, by using modular rebate forms with ferrule supports that are cast in and later withdrawn, exposing the ferrules for reinforcing bar installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If reinforcement is cast into the core with the main formwork and rebate form in place, then the reinforcement can be positioned within the rebate, but the reinforcement must be bent to lie along the interior of the rebate form which reduces ductility and requires time-consuming bending and straightening operations

Engineering Contradiction:

Improveease of reinforcement placementVSAvoidtime for bending and straightening reinforcement

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

Ferrules are pre-installed onto the rebate form at the desired locations before the concrete pouring operation begins. This preliminary placement eliminates the need for bending and straightening reinforcement during construction, as the ferrules remain attached to the formwork throughout the pouring process and are only removed after stripping, with reinforcement already in its final straight configuration.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Ferrules serve as intermediary components that bridge the rebate form and the reinforcement. The ferrules are attached to the rebate form during construction, allowing reinforcement to be inserted into them after stripping without requiring bending operations. This intermediary element simplifies the overall process by decoupling the formwork removal from reinforcement installation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If reinforcement is bent to lie along the interior of the rebate form for casting, then it can be positioned correctly, but the bending and subsequent straightening reduces ductility which is undesirable

Engineering Contradiction:

Improveprecision of reinforcement positioningVSAvoidductility of reinforcement

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

Ferrules are pre-positioned on the rebate form at exact locations before concrete pouring. This ensures precise reinforcement positioning is achieved without requiring the reinforcement itself to be bent, thereby maintaining its ductility while achieving the required positioning precision.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of bending the reinforcement to fit within the rebate form during casting, the invention inverts the approach by attaching ferrules to the rebate form and inserting straight reinforcement into them after stripping. This reverses the traditional sequence and eliminates the harmful bending operation while maintaining positioning accuracy.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of operation

If the rebate form is of hollow or box-like construction to receive bent reinforcement, then reinforcement can be positioned within the rebate, but the process becomes complex and time-consuming

Engineering Contradiction:

Improveease of reinforcement installationVSAvoidcomplexity of rebate form construction

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The invention extracts the reinforcement positioning function from the rebate form structure itself. Rather than requiring the rebate form to be hollow or box-like to contain bent reinforcement, ferrules are attached to the rebate form to provide the containment function, allowing the rebate form to maintain its simpler structural design while achieving the same positioning objective.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Ferrules act as intermediary components that simplify the rebate form design. Instead of requiring complex hollow or box-like rebate forms to accommodate bent reinforcement, the ferrules provide the necessary containment and positioning functions, allowing the rebate form to remain structurally simple while achieving precise reinforcement installation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8647542B2Method of forming a rebate in a surface of a slip form cast core using a rebate form with ferrule support

Publication Date: 2014.02.11 ITW CONSTR PRODS AUSTRALIA

AI summary

A formwork system for use in slip form casting central cores of high rise buildings provides a rebate form for a rebate at the level of each floor slab which is subsequently to be cast. The rebate form is designed to carry ferrules to be cast into the core at the level of the rebate to provide anchoring points for incorporation of reinforcement associated with the floor slab. The ferrules are carried from the rebate form via plugs which are stripped from the ferrules after casting when the rebate form and main slip form to which it is attached is withdrawn.