High-Strength Bolts: Assemblies, Holes, and Caltrans Verification Testing
"High-Strength Bolts: Assemblies, Holes, and Caltrans Verification Testing" is lesson 3 of 6 in the Structural Steel (C-51) Learning Hub. It opens with "What Makes Up a High-Strength Fastener Assembly" and works through 5 short steps, then a worked example you can check yourself against.
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Steps in this lesson
What Makes Up a High-Strength Fastener Assembly
Hole Sizes and Preparation
Installing the Assembly
Test the Lot Before You Install
Verification Testing After Tightening
The worked example in the course applies this lesson to a realistic job in 6 steps, from "Largest finished hole" through "Verification count".
What you'll be able to do
Explain the main idea of "High-Strength Bolts: Assemblies, Holes, and Caltrans Verification Testing" in plain language you can use on the exam.
Apply this step with confidence: "Installing the Assembly".
Apply this step with confidence: "Test the Lot Before You Install".
Apply this step with confidence: "Verification Testing After Tightening".
Test yourself on the worked example and the quick-check quiz inside the classroom.
The diagram for this lesson, exactly as it appears in the Learning Hub.
The first steps of this lesson
Step 1: What Makes Up a High-Strength Fastener Assembly
Caltrans Section 55 requires bolted structural steel joints to be made with HS fastener assemblies, either (1) an HS bolt, nut and hardened washer (a direct tension indicator may be used with them) or (2) a tension control bolt, nut and hardened washer. Each length and diameter of assembly used in any single joint must come from the same rotational capacity lot, and you keep a record of which lots go in each joint. The 2025 CBC sends the design and installation of steel connections to the referenced standards and sends special inspection of high-strength bolt installation to §1705.2. The pretension values and nut-rotation tables live in the RCSC Specification that Caltrans adopts by reference; they are not printed in any California code book on disk, so this lesson does not teach them. Source: 2025 Caltrans Standard Specifications, Section 55-1.02E(6)(a) (text, page 903); 2025 CBC §2201.4 (Ch. 22 text, page 3).
Step 2: Hole Sizes and Preparation
Bolt holes may be punched full size, drilled full size, subpunched and reamed, or subdrilled and reamed. A finished hole must be round within 1/32 in, perpendicular to the plane of the connection within 1 in 20, and at most 1/16 in larger than the nominal bolt diameter for bolts under 1.0 in, or at most 1/8 in larger for bolts of 1.0 in and over. All holes must pass a pin 3/16 in smaller than the nominal hole size. Do not punch or subpunch ASTM A36 steel thicker than 7/8 in, or HS structural steel thicker than 3/4 in. Source: 2025 Caltrans Standard Specifications, Section 55-1.02E(6)(b)(i) and (ii) (text, page 904).
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.
Independent exam preparation. Contractors Classroom is not affiliated with the Contractors State License Board, and no course can guarantee a passing result.
