Modern Steel Construction - June 2021
STEEL QUIZ
2021-05-07 02:42:55
This month’s quiz focuses on the recently published 2020 RCSC Specification, which is available at aisc.org/specifications.
(See “Bolting Ahead” in the April 2021 issue, available in the Archives section at www.modernsteel.com, for more on the new RCSC Specification.)
1 True or False: When using the twistoff tension-control bolt method of pretensioning, the spline end is checked twice.
2 Which of the following pieces of information is a new addition to the list of things the engineer of record (EOR) may specify that may require their attention or approval when preparing the contract documents?
a. Use of alternative-design bolting components, assemblies, or installation methods, including the corresponding installation and inspection requirements that the manufacturer provides
b. Use of thermal cutting of bolt holes that are produced freehand or are intended for use in cyclically loaded joints
c. Specifying when threads must be excluded from the shear plane, if applicable
d. Use of a value of Du other than the value provided in Section 5.4.
3 True or False: The expanded provisions on alternative - design bolting components now provide additional limitations for manufacturing, dimensions, and inspection of bolting components but do not allow for alternative coatings.
4 True or False: The storage and lubrication requirements provided apply to all bolting components and assemblies that are to be used on site.
5 Which of the following is the nominal slotting short-slotted bolt hole dimension for a 1¼ in. diameter bolt?
a. 15/16 × 15/8 in.
b. 13/8 × 15/8 in.
c. 13/8 × 15/16 in.
d. 1¼ × 15/8 in.
6 Which of the following is the correct range of turns for a snugtight condition using turn-of-nut pretensioning for a bolt with a length five times that of the diameter, with both outer faces normal to the bolt axis?
a. ½ turn to 5/6 turn
b. 2/3 turn to 5/6 turn
c. 1/3 turn to 2/3 turn
d. ½ turn to 2/3 turn
7 True or False: Compressible materials are permitted in the grip of a snug-tightened thermal break joint in the primary load resisting system so long as the bolts are subject to shear and long-term loads are limited to 30% of the material’s ultimate load.
8 Why is preinstallation verification testing essential?
a. It verifies the adequacy and proper use of the specified pretensioning method to be used
b. It demonstrates the suitability of the bolt tightening equipment to be used during installation
c. It determines the installation torque for the calibrated wrench method of pretensioning
d. All of the above
9 True or False: Torque measurement results are not always consistent for inspection.
ANSWERS
1 True. Section 7.2.3 describes that after snug tightening, an intermediate verification is required to ensure the splined end is not severed, as well as a final verification after pretensioning to ensure it is severed.
2 c. The Commentary to Section 1.6 was expanded to include additional considerations for the engineer when preparing the contract documents.
3 False. Section 2.12.3 does not prohibit alternative coatings but states that they shall meet the performance criteria specified in the alternative coating standard and shall not have a detrimental effect on the bolting components or assemblies.
4 False. Section 2.10.7 exempts temporary bolts from the stated requirements.
5 b. Table 3.1 was updated to indicate that the maximum hole size is permitted to be 1/8 in. over the bolt diameter for bolts with a diameter greater than 1 in.
6 d. The nut rotation tolerance was revised in Table 8.1 to +60° (1/6 turn) and -0°. Using the ½ turn stated in the table, this results in a range of a minimum of ½ turn and a maximum 2/3 turn.
7 False. The commentary to Section 1.1 contains a newly added discussion on the use of compressible material in the grip of a joint. The 30% ultimate load recommendation still applies, but thermal break joints are not intended for primary load-resisting systems.
8 d. All the tasks, including two others not shown, are listed as necessary reasons. Additional clarification on the need for preinstallation verification is now provided in the Commentary to Section 7.
9 True. The Commentary to Section 9 explains that torque measurements are dependent on the friction between bearing faces and threads and are influenced by the lubrication conditions of the bolting components. Instead, routine observation of installation methods is always preferred.
STEEL SOLUTIONS CENTER
Everyone is welcome to submit questions and answers for the Steel Quiz. If you are interested in submitting one question or an entire quiz, contact AISC’s Steel Solutions Center at 866.ASK.AISC or solutions@aisc.org.
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