ACI 318 / ACI 133 - Coupler Codes and Standard in Building code Requirements for Structural Concrete and Commentary

American Concrete Institute (ACI) Building Code 318 -

1. Building code Requirements for Structural Concrete and Commentary

ACI 318 / ACI 133

ACI 318 / ACI 133
Type of Test Required	Why ! (purpose of the test)	What is the Criteria ?
Static tensile strength test	Tensile strength of the Rebar joint (Rebar to Coupler Splice) joint	> 1.25fy for Type 1 100% fu & >1.25fy for Type 2   Fu = Ultimate Strength of bar Fy = Yield Strength of bar
Slip Test	Used to make sure that the plastic movement (slip) between the reinforcement bars with in the Mechanical Splice, when Loaded in tension	The bar-splice assembly shall be loaded in tension to nominal zero load, not exceeding 4Mpa (600 psi).   The bar-splice assembly then be loaded in tension with a loading rate between 70 Mpa/min to 690 Mpa/min.
Montonic Tensile test for failure	Used to measure the performance of a mechanical splice under an increasing tensile load. The load is increased until failure is reached.	Monotonic Tension Tests shall be conducted in accordance with the provisions of Test Methods ASTM A370. Up to the yield point, Load shall be applied at the rate between 70 Mpa/min (10,000 psi) and 700 Mpa (100,000 psi)
Monotonic Compression Test	This test is used to ascertain the performance of the bar-splice assembly under an increasing compressive load.	Monotonic Compression Tests shall be conducted in accordance with the provision of Test Methods ASTM A370 and E9.   For strain rate controlled tests, the load shall be applied in accordance with 8.7 of Test Methods ASTM E9.   Typical maximum compressive load imposed in this test is 125% of the specified yield strength of the reinforcement bar.
Uniform Cyclic Load Test (Seismic Elastic)   Stage 1	Used to make sure how a mechanical splice performs when subjected to alternating tension and compression loads for a given number of cycles.   Each cycle may exceed the specified yield strain of the reinforcement bar and is intended to stimulate an earthquake loading.	The test specimen shall be loaded between 70 Mpa/min to 690 Mpa/min until the strain specified has been reached. The loading direction shall be reversed until the specimen has reached the compressive loads specified. 20 Cycles of stress variation from 50% compressive – 95% tensile of fy
Stepped Strain Cyclic Load Test (Seismic Plastic)   Stage 2,3 & 4		4 Cycles of stress variation from (-50%fy to 2εy) 4 Cycles of stress variation from (-50%fy to 5εy)   Following the last cycle, the specimen shall be loaded to failure in tension.
Maximum % Elongation		0.1 mm

 

In Accordance with ACI 318 – American Concrete Institute (ACI) Building Code 318,2008

Code is basically a performance based code and categorizes splicing into two groups

Type 1 – Joint require to achieve 1.25fy as minimum.

Type 2 – Joint require to comply 1.25fy and meet specified tensile strength of rebar.

For Eg :For Fe500

Type 1 – Tensile strength is not expected to be less than 1.25fy =625N/mm^2 

Type 2 - Tensile strength acceptance is at 700 N/mm^2