6.2 Mechanical Splices and Couplers (Type 1 and Type 2 Requirements)

6.2 Mechanical Splices and Couplers

Mechanical splices transfer forces through an approved connecting assembly. A sleeve can reduce the space needed for an overlap, but its body can reduce available cover or clearance. Read the plans for the specified splice type and location and use the installation instructions for the actual model.

Recognize the connection and the installation checks

A product approval may be supported by an ICC Evaluation Service (ICC-ES) Evaluation Report. Check its scope, code editions, approved bar sizes and grades, conditions of use and inspection requirements. Obtain the manufacturer's installation instructions referenced by the approval. If a transition splice is needed, confirm that the exact pair of sizes and grades is covered. Do not infer the transition capacity from the sleeve size or an unrelated report.

Apply the ACI 318-19 strength and location checks

Under Section 25.5.7.1, a mechanical splice must develop at least $1.25f_y$ of the bar in tension or compression as required. Under Section 18.2.7.1, a Type 1 splice meets Section 25.5.7 and a Type 2 splice also develops the specified tensile strength of the spliced bars. Use the specified bar strengths for the classification. The classification is separate from product approval and from installation evidence.

For Grade 60, $1.25(60)=75$ ksi. In the -16 ASTM editions, A706 Grade 60 has specified minimum tensile strength of 80 ksi and A615 Grade 60 has 90 ksi. For the A706 example, the tensile check for Type 2 is 80 ksi, while the A615 example uses 90 ksi. For Grade 80 the base check is $1.25(80)=100$ ksi. Verify the product listing for the actual bar specification and grade.

Section 18.2.7 applies to special moment frames and special structural walls. With the Grade 60 Type 2 exception, Section 18.2.7.2 restricts mechanical splice locations within twice the member depth from the column or beam face in a special moment frame or from a critical section where reinforcement yielding is likely under inelastic lateral displacements. Type 2 splices on Grades 80 and 100 are subject to the location restriction. Section 18.9.2.1(c) separately requires beam reinforcement mechanical splices in the covered precast ductile connections to be at least $h/2$ from the joint face and to satisfy Section 18.2.7.

Worked location example. In a 24-inch-deep cast-in-place special moment frame beam, the end-zone check is $2h=48$ inches from the column face. A Type 1 splice shown 36 inches from the face is inside this limit. A Type 2 splice on Grade 80 reinforcement at that location has the same restriction. For Type 2 on Grade 60, check the exception, approved location and product conditions.

Verify installation in the field

Start with the approved splice location and identification. Check bar preparation, sleeve model, alignment, insertion and clearances. Use the specified field observation and any test frequency in the approved inspection documents or evaluation. ACI 318-19 Section 26.6.1.1(e) identifies splice type and location as design information. Model IBC Table 1705.3 covers reinforcement placement, and an applicable product approval can specify additional checks.

For example, ICC-ES ESR-2495 describes certain Bar-Lock L- and S/CA-series sleeves with lock-shear bolt heads designed to shear off at their specified installation torque. Head breakaway is a check for that design. It does not verify bar grade, insertion, alignment or other steps. Treat an incomplete assembly according to the applicable procedure and record the result. For a torque-controlled threaded product, verify the required torque and tool method without transferring limits from another model.

Measure spacing and cover where the splice assembly enlarges the reinforcement envelope. Use the approved criteria, including any cover measured to the outside of the assembly in the evaluation report. For coated bars, check the required coupler coating and repair where specified. Record the splice location and identification, discrepancies and the verified disposition.