3.1.4.1
Lap Splices
Lap splices shall be used only for bars smaller than size 45 14 and welded
wire fabric. Lapped bars may be placed in contact and securely tied or
spaced transversely apart to permit the embedment of the entire surface of
each bar in concrete. Lapped bars shall not be spaced farther apart than
1/5 the required length of lap or 150 mm. 6 inches.
3.1.4.2
Butt-Splices
Butt-splices shall be used only for splicing size 45 and 55 14 and 18 bars
and for splicing #11 bars to larger bars except where otherwise shown or
authorized. Butt-splices shall be made by a method which develops splices
suitable for tension, compression and stress reversal applications. Welded
butt-splices shall be full penetration butt welds. Butt-splices shall
develop 90 percent of the specified minimum ultimate tensile strength of
the smallest bar of each splice. Bars shall be cleaned of all oil, grease,
dirt, rust, scale and other foreign substances and shall be flame dried
before splicing. Adequate jigs and clamps or other devices shall be
provided to support, align and hold the longitudinal centerline of the bars
to be butt-spliced in a straight line.
Butt-splices shall be as follows:
a. Thermit Welded Butt Splices - Bars to be thermit welded shall be
restricted to steel shown by heat analysis to have a sulfur content not
exceeding 0.05 percent. The ends of bars to be thermit welded shall be
cut square and smooth. Flame cutting will be permitted provided
grinding is employed to remove the resulting scale and to square and
smooth the cut ends to a condition equivalent to a saw cut. No
shearing will be permitted. Bars shall be cleaned and flame dried
before splicing. The joint shall be properly aligned in the mold with
a gap opening in accordance with the manufacturer's recommendations.
Charging and firing shall conform to the manufacturer's
recommendations. The end of bars and the welded mold shall be
preheated before welding to a temperature of not less than 40 degrees C
100 degrees F and the mold shall be left in place for at least 15
minutes after ignition. Risers shall be broken or burned off after
removing the mold. Tension splices shall be staggered longitudinally a
minimum of 1500 mm 5 feet so that no more than half of the bars are
spliced at any one section or as otherwise indicated.
b. Mechanical Butt-Splices - Mechanical butt-splices shall be an
approved exothermic, threaded coupling, swaged sleeve or other positive
connecting type. Bars to be spliced by a mechanical butt-splicing
process may be sawed, sheared or flame cut provided the ends of sheared
bars are reshaped after shearing and all slag is removed from the ends
of flame cut bars by chipping and wire brushing prior to splicing.
Surfaces to be enclosed within a splice sleeve or coupling shall be
cleaned by wire brushing or other approved method prior to splicing.
Splices shall be made using manufacturer's standard jigs, clamps,
ignition devices and other required accessories. In addition to the
strength requirements specified paragraph BUTT-SPLICES the additional
deformation of number 45 14 and smaller bars due to slippage or other
movement within the splice sleeve shall not exceed 0.38 mm (unit strain
0.0015 mm/mm) 0.015 inches (unit strain 0.0015 inches/inch) beyond the
elongation of an unspliced bar based upon a 250 mm 10 inch gage length
spanning the extremities of the sleeve at a stress of200 MPa. 30,000
psi. The additional deformation of number 55 18 bars shall not exceed
0.75 mm (unit strain 0.003 mm/mm) 0.03 inches (unit strain 0.003
inches/inch) beyond the elongation of an unspliced bar based upon a 250
SECTION 03201
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