Reinforcing Steel (C-50) · Lesson 3 of 7

Lap Splice Length: What Caltrans Section 52 and the CRC Print

"Lap Splice Length: What Caltrans Section 52 and the CRC Print" is lesson 3 of 7 in the Reinforcing Steel (C-50) Learning Hub. It opens with "What a Lap Splice Is and How It Is Made" and works through 5 short steps, then a worked example you can check yourself against.

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Steps in this lesson

  1. What a Lap Splice Is and How It Is Made
  2. Caltrans Lap Lengths in Bar Diameters (Section 52-6.03B)
  3. Bundles, Stagger, and Bars You May Not Lap
  4. Residential Walls and Footings: CRC Table R608.5.4(1)
  5. Put Laps Into the Takeoff

The worked example in the course applies this lesson to a realistic job in 6 steps, from "Find the nominal diameter" through "Epoxy-coated alternative".

What you'll be able to do

  • Explain the main idea of "Lap Splice Length: What Caltrans Section 52 and the CRC Print" in plain language you can use on the exam.
  • Apply this step with confidence: "Bundles, Stagger, and Bars You May Not Lap".
  • Apply this step with confidence: "Residential Walls and Footings: CRC Table R608.5.4(1)".
  • Apply this step with confidence: "Put Laps Into the Takeoff".
  • Test yourself on the worked example and the quick-check quiz inside the classroom.
LAP SPLICE LENGTH: FROM THE CODE PAGE2025 Caltrans Std Spec Sec. 52-6.03B and 52-1.04 | 2025 CRC Table R608.5.4(1)#6 LAP: 45 DIAMETERS OF THE SMALLER BARbar A (#6)bar B (#6)lap = 45 x 0.750 = 33.75"(2'-9-3/4")bars in contact, wired togetherStagger splices: distance = lap length of largest barCALTRANS LAP LENGTHS (in.)Bardb45db65db epoxy#40.50022.50032.500#50.62528.12540.625#60.75033.75048.750#70.87539.37556.875#81.00045.00065.000Grade 60, #8 and smaller. #9-#11: 60db(epoxy 85db). Smaller bar governs.Sec. 52-6.03B | db: Sec. 52-1.041Uncoated Grade 60, #6: 45 x 0.750 = 33.75" per splice2Extra length paid per splice: 33.75 / 12 = 2.8125 ft x 1.502 lb/ft = 4.224 lb340 splices: 40 x 4.224 = 169.0 lb added to the takeoff4Same wall in epoxy-coated bars: 65 x 0.750 = 48.75" (4'-0-3/4") per spliceRESULT: 33.75" lap, 169 lb of lap steel for 40 splicesSmaller bar governs. No laps for #14, #18, hoops, or with under 2" clear to the nearest bar.CC
The diagram for this lesson, exactly as it appears in the Learning Hub.

The first steps of this lesson

Step 1: What a Lap Splice Is and How It Is Made

A lap splice passes load from one bar to the next by overlapping them. Caltrans Section 52-6.03B says splices made by lapping must consist of placing reinforcing bars in contact and wiring them together while maintaining the alignment of the bars and the minimum clearances. Section 52-6.01A names the three types of splice: lap, service and ultimate butt. For concrete in buildings, 2025 CBC Section 1901.5 requires the construction documents to show the anchorage length of reinforcement and the location and length of lap splices, so the bar list you are given should already state them.

Step 2: Caltrans Lap Lengths in Bar Diameters (Section 52-6.03B)

For uncoated and galvanized bars (ASTM A615 Grade 60, A706, A1035 or A767 Class 1) the lap must be at least 45 diameters of the smaller bar spliced for bars #8 and smaller, and 60 diameters for #9, #10 and #11. For epoxy-coated bars and their alternatives the minimums are 65 diameters (#8 and smaller) and 85 diameters (#9 to #11). For ASTM A615 Grade 40 bars: 30 diameters (#8 and smaller) and 45 diameters (#9 to #11). Find the diameter in the Section 52-1.04 table: for example #6 = 0.750 in., so 45 x 0.750 = 33.75 in.

The remaining 3 steps, the worked example and the quiz are in the course. This is a preview. The full lesson, with the step-by-step explanations, a worked example and a quick-check quiz, is inside the classroom.

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