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Technical Information

Mechanical Splicing

Moment BarBreak Coupler

BarBreak Connection Splice

Seismic Design

Post Tensioning

Control Permeability Formwork (CPF)

Moment Patented ‘Barbreak’ Connection Splice

Moment Patented ‘Barbreak’ mechanical connections conform fully with applicable codes include BS 8110 and ACI 318/318R Section 21.2.6. for both types ‘Non-Barbreak’ & ‘Barbreak’ Mechanical Splices. Barbreak Mechanical Connections actually provide defined ductile behaviour and performs like continuous piece of bar Fig 3. Moment Patented ‘Barbreak Mechanical Connection’ performs in excess of 150% beyond the yield point of the bars

(a) When a test is made on a representative gauge length assembly comprising reinforcement of the size, grade and profile to be used and a coupler of the precise type to be used, the permanent elongation after loading to 0.6 fy should not exceed 0.1mm, and

(b)The design ultimate strength of the coupled bar should exceed the specified characteristic strength by the percentage specified in Clause 11 of BS 4449:1997, so that yielding will tend to occur at the reinforcement bar adjacent to the mechanical connection before failure in the mechanical connection (defined as ‘Barbreak’).

Moment Barbreak mechanical connections perform beyond the yield point of the bar whereas Lap Splices are only defined in the plastic area. This indicates that the Moment ‘Barbreak’ connection which work as a continuous bars provides additional strength and safety all round independent of the quality of the surrounding concrete.

Design Codes And Specifications Splice

In reinforced concrete design, the Structural Engineer is faced with the task of determining where and how reinforcing bars must be spliced in a structure. This he must do because of his familiarity with the particular requirements of the structure combined with statutory regulations.

Due to the minimum connection strength required, it is generally assumed in design that the occurrence of a mechanical connection of two reinforcing bars does not result in a reduction of the anticipated structural strength as well as the longitudinal stiffness and longitudinal ductility of the reinforcing steel, which the reinforced concrete member would have had with a continuous unspliced bar. That is, it is assumed that the use of a mechanical connection does not introduce a structural weakness that could jeopardize the overall structural performance.

Design requirements of the applicable codes as in ACI318, 349 or AASHTO and BS 8110 or BS5400 Pt 4 – Code of practice for design of concrete bridges, generally specify a minimum connection strength e.g. Clause 5.8.6.6 States;

Fig 3