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Weekly Quiz Answers

Here are the answers to Modern Steel Construction's Weekly Quiz questions! 

October 6, 2021

True or False: The engineer of record (EOR) should always specify bolt size and connection type on drawings, even when connection design is delegated.
Answer:
False. Providing the end reactions and allowing the fabricator to select the connection type and size to achieve the required strength provides more flexibility. It also typically leads to a more efficient configuration conducive to the shop’s capabilities as well as a more economical project for the owner.


September 29, 2021

True or False: Weathering steel corrosion resistance is enhanced by applying a coating system.
Answer:
False. When properly detailed and used in accordance with FHWA Technical Advisory 5140.22 (available at fhwa.dot.gov/bridge/t514022.cfm), weathering steel forms a protective oxide layer from its exposure to wet/dry cycles. The application of a coating system inhibits this process and only adds to the initial and long-term maintenance costs of the bridge. Research has shown that design and maintenance practices may be more influential than climate to the performance of weathering steel.


September 22, 2021

What is the term for a section that is capable of developing a fully plastic stress distribution and possessing a rotational capacity of approximately three before the onset of local buckling?
a. Stiffened element
b. Compact section
c. Slender section
d. Unstiffened element
Answer:
b. Compact section. This definition is provided in the Specification glossary. Limiting width-to-thickness ratios for compact/non-compact sections can be found in Table B4.1b. Submitted by Jeremy Rollins, CLC Engineering.


September 15, 2021

Which of the following statements are true about erection requirements for AESS:
a. Tack welds not incorporated into final welds shall be ground smooth.
b. All bolt heads in connections shall be on the same side, as specified, and consistent from one connection to another.
c. Both a and b are correct.
d. Both a and b are incorrect.
Answer:
c. Both of these requirements must be satisfied according to Section 10.6 of the AISC Code.


September 8, 2021

Can you install powder-actuated fasteners (PAFs) in the casing of a buckling restrained brace (BRB)?
a. Yes, PAFs are permitted to be installed along the full length of brace.
b. Yes, but only in the middle third of the casing.
c. Yes, but only as specifically directed by the BRB manufacturer.
d. No, PAFs are never permitted in the casing of a BRB.
Answer:
c. The core steel is considered the protected zone. From the outside of the brace, the core configuration cannot be verified, so there is a possibility of damaging the core steel if using a fastener that penetrates the casing, such as a PAF. This configuration can be coordinated with the manufacturer to allow certain sizes or locations of PAFs. Submitted by Shauna Kean, Coughlin Porter Lundeen.


September 1, 2021

True or False: All threaded components of a base plate fastener assembly (anchor rod) should be galvanized by the same process. 
Answer:
True. Design Guide 1: Base Plate and Anchor Rod Design states, in Section 2.5: “Mixing of rods galvanized by one process and nuts by another may result in an unworkable assembly. It is recommended that galvanized anchor rods and nuts be purchased from the same supplier and shipped preassembled. Because this is not an ASTM requirement, this should be specified on the contract documents.” Submitted by Tiffany Rowan.


August 25, 2021

True or False: ASTM F3125 Grade A490 bolts are labeled as Group A, and Grade A325 bolts are labeled as Group B.
Answer:
False. Section J3.1 in the AISC Specification categorizes ASTM F3125 Grade A325 bolts as Group A and A490 bolts as Group B. Submitted by Tracy Donoghue, KPFF.


August 18, 2021

Which of the following backing materials are permissible to use without removal for prequalified CJP welds found in AWS D1.1?
a. steel
b. copper
c. ceramic
d. all of the above
e. both a and b
Answer:
a. Steel backing is “prequalified” by AWS D1.1 to be used without removal. AWS D1.1:2015 allows copper and ceramic backing to be used with prequalified welds if the following conditions were met: The prequalified joint detail does not contain steel backing or spacers, the joint is back-gouged, and the back-gouged joint is back-welded. More information can be found in AISC Design Guide 21: Welded Connections—A Primer for Engineers. Submitted by Rick Overgard, Atlantic Steel Detailing Services, edited by AISC.


August 11, 2021

If you wanted to minimize the magnetization of stainless steel, which of the following would be helpful?
a. Minimizing welding
b. Using ferrite-free welding rod
c. Using Type 304N or Type 316N instead of regular Type 304 or Type 316 steel
d. Subsequent annealing
Answer:
d. Subsequent annealing. AISC Design Guide 27: Structural Stainless Steel states, in Section 2.4: “Heavy cold working, particularly of the lean alloyed austenitic steels, can also increase magnetic permeability; subsequent annealing would restore the non-magnetic properties. For nonmagnetic applications, it is recommended that further advice be obtained from a steel producer.” Submitted by Richard de Campo, Poss Architecture + Planning.


August 4, 2021

What is the maximum difference between any two stair riser heights allowed by the International Building Code (IBC) on a single flight for dimensional uniformity? 
a. ⅛ in.
b. ⅜ in.
c. ½ in.
d. ⅝ in.
Answer:
b. ⅜ in. Table 3-8 of Design Guide 34: Steel-Framed Stairway Design indicates that IBC 2015 Section 1011.5.4 requires a ⅜ in. variation in tread depth or riser height within a stair flight. Note that requirements must be verified with the local authority having jurisdiction, and OSHA 1910.25(b)(3) requires that treads and risers shall have uniform heights between landings. Submitted by Austin Dowell, Snyder Engineering.


Week of July 28, 2021

True or False: Any beam lengths are available from the steel mill.
Answer:
True, but steel must be ordered from a mill typically in bundles of at least 10 tons for each size and length. If the beams are ordered from a service center, they are available in 5-foot increments from 20 feet to 60 feet long.


Week of July 21, 2021

For a project that requires both AISC 360 and AISC 341, where can I find a list of all the items that are required for Special Inspection of structural steel?
a. Chapter J of AISC 360
b. Chapter N of AISC 360
c. Chapter J of AISC 341
d. Both b and c
Answer:
d. Chapter N of AISC 360 Specification for Structural Steel Buildings and Chapter J of the Seismic Provisions contain all the provisions for Special Inspection of structural steel as required in the IBC.


Week of July 14, 2021

True or False: The Workable Gage dimensions in Table 1-1 of the Manual are mandatory.
Answer:
False. These gages are listed to ensure that bolts can be inserted and tightened. Any gage can be used as long as the edge distance requirements are met and the bolts can be inserted and tightened.


Week of July 7, 2021

Which of the following is generally more true of steel construction today?
a. Least weight is always least cost.
b. Lowest pounds per square foot is always the best design.
c. The project with the overall lowest cost of construction (least labor) is the winner, regardless of the steel metrics.
d. None of the above.
Answer:
c. The project with the overall lowest cost of construction (least labor) is the winner, regardless of the steel metrics.


Week of June 30, 2021

True or False: Base plates and cap plates using stiffener are generally more economical than using thicker plate materials.
Answer: 
False: The fabrication costs of those stiffeners can quickly add to the cost of the base and cap plates, driving up costs.


Week of June 23, 2021

True or False: Stiffeners and doublers are cheaper than upsizing beams and columns to eliminate them.
Answer:
False. Stiffeners and doublers are almost always more expensive than designing heavier members whenever possible because of the labor of making and welding them in place.


Week of June 16, 2021

Name a commonly overused weld symbol that can easily drive up project costs when not judiciously applied:
a. Weld all round
b. Complete joint-penetration groove welds
c. Triple axel fillet welds
d. Both a and b
Answer:
d.


Week of June 9, 2021

True or False: There is minimal difference in cost between single and double-pass welds.
Answer:
False. Overspecifying weld sizes is very expensive and time-consuming especially when the resulting size is no longer a single-pass weld.


Week of June 2, 2021

True or False: Most HSS column connections require through-plates.
Answer:
False. It's only the rare HSS column that has a wall thin enough to require a through-plate; most can support a single plate welded to the face without the costly extra work.


Week of May 26, 2021

Slip critical connections should be used only _____:
a. when the connection design doesn’t trust their calculations.
b. when specific cases call for them in the RCSC Specification and its Commentary.
c. for economical steel structures.
d. unless the drawings indicate otherwise.
Answer:
b. when specific cases call for them in the RCSC Specification and its Commentary.


Week of May 19, 2021

Complete the sentence: ______-sided connections (single plates, single angles, tees, etc.) make erection easier, faster, and safer.
a. Three
b. Lop
c. Double
d. One
Answer:
d. One


Week of May 12, 2021

True or False: The Steel Construction Manual is AISC’s only source of design examples and design tables for structural steel design.
Answer:
False. The Companion to the 15th Ed. Manual (a two-volume set), available at aisc.org/manualresources, is filled with extra design examples and design tables for 65- and 75-ksi W-shapes.


Week of May 5, 2021

True or False: The exterior steel plates of SpeedCore walls require no additional fire protection.
Answer:
True. SpeedCore does not require external fire protection materials.


Week of April 28, 2021

As the most sustainable structural material in the nation, structural steel is often described as a:
a. cradle-to-gate material
b. cradle-to-cradle material
c. cradle-to-bottle substance
d. none of the above
Answer:
b. cradle-to-cradle material.


Week of April 21, 2021

True or False: In steel bridges, the lightest cross-frame design is always the best cross-frame design.
Answer:
False. Consistent and more standard girders and cross-frames are usually better than less weight.


Week of April 14, 2021

True or False: Providing actual loads on drawings generally allows connection design to proceed faster and more economically with fewer RFIs.
Answer:
True. When actual reactions and moments are provided, connection designers have essential information for developing efficient designs.


Week of April 7, 2021

True or False: Lighter shapes are always faster and cheaper to fabricate.
Answer:
False. In some cases, bumping up the member size can eliminate costly fabrication details or the need for camber in the shop.


Week of March 31, 2021

Structural steel shapes rolled in the United States consist of what percentage of recycled steel content?
a. 13%
b. 41
c. 78%
d. 93%
Answer:
d. 93% recycled steel content!


Week of March 24, 2021

Which of the following describes a process where the structural steel fabricator provides input during the conceptual and design phases of a project to increase construction speed and decrease costs?
a. early engagement
b. design-bid-build
c. late arrangement
d. handshake agreement
Answer:
a. early engagement.


Week of March 17, 2021

True or False: A connection that requires ½ inch of fillers is required to have the bolt capacity reduced by 10%.
Answer:
True: Section J5.2 requires that if the fillers exceed ¼ inch, the shear strength of the bolts shall be multiplied by 1 – (0.4)(t – 0.25). So for ½ inch of fills the factor is 1 – (0.4)(0.5 – 0.25) = 0.90.


Week of March 10, 2021

True or False: Slip Critical bolts must be checked for bearing as well as slip.
Answer:
True: Slip Critical bolts may slip into bearing, therefore the material and the bolt must be check to confirm it will meet the requirements for bearing.


Week of March 3, 2021

True or False: The distance between standard holes in a bolted connection is required to be 3 inches or greater.
Answer:
False: Section J3.3 of the Specification states, “The distance between centers of standard, oversized or slotted holes shall not be less than 2-2/3 times the nominal diameter of the fastener. However, the clear distance between bolt holes or slots shall not be less than d.” (d is the diameter of the bolt)


Week of February 24, 2021

True or False: The maximum bolt hole diameter is 1/16 inch larger than the bolt diameter.
Answer:
False: For holes 1 inch and larger in diameter, the bolt hole size is permitted to be 1/8 inch larger than the bolt diameter.


Week of February 17, 2021

True or False: If nothing is stated in the design documents or specification, all connections on a project are required to be fully tensioned.
Answer:
False: In Section J3 of the Specification it states, “Bolts to be tightened to a condition other than snug tight shall be clearly identified on the design drawings.”


Week of February 10, 2021

True or False: Given that section N6 of the AISC Specification states that QA (Quality Assurance) inspection is permitted to be waived by the AHJ (Authority Having Jurisdiction), this means that no NDT is required on such projects.
Answer:
False: The Commentary to Section N6 states, “Granting a waiver of QA inspections in a fabrication shop does not eliminate the required NDT of welds: instead of being performed by QA, such inspections are performed by the fabricator’s QC.”


Week of February 3, 2021

True or False: Round HSS sections that meet pipe dimensions are made from material meeting ASTM A53.
Answer:
False: Round HSS sections used for structural purposes are made from material meeting either ASTM A500 Grade C, A1085, or A1065. ASTM A53 is a specification for hydraulic pipe.


Week of January 27, 2021

True or False: A single plate shear connection (shear tab) with ¾-inch diameter bolts must have a plate thickness no more than 1 inch thick.
Answer:
True: A single plate shear connection plate shall not be thicker than 1/16 inch larger than the bolt diameter so that bolt plowing can occur to develop the required rotation in the connection.


Week of January 20, 2021

True or False: All HSS material shall be designed to consider the wall thickness as being 0.93 times the nominal wall thickness.
Answer:
False. While this is true for HSS material that is produced in accordance with ASTM A500, HSS material produced in accordance with ASTM A1085 and A1065 can be designed utilizing the full nominal wall thickness.


Week of January 13, 2021

True or False: A fillet weld should be sized based upon the thickness of the thicker of the two materials being joined.
Answer:
False. In accordance with Specification Section J2.2-2b(b)(1) a fillet weld shall not be greater than the thickness of any material it is joining.


Week of January 6, 2021

What is the basic cleaning requirement for steel in the AISC Code of Standard Practice when nothing else is specified in the contract documents?
a. SP2
b. white metal blast-cleaned
c. ESPN
d. SPF-30
Answer:
a. SP2.SSPC SP2 is specified in Section 6.5.2. of the AISC Code of Standard Practice. When alternative treatment is required, it must be specified in the contract documents.


2020 Answers

Week of December 30, 2020

Which of the following does not represent an acronym for a type of moment connection? Hint: See AISC 358.
a. WUF-W
b. BRBF
c. RBS
d. KBB
Answer:
b. BRBF, or buckling restrained braced frame, is a type of lateral system using buckling restrained braces.


Week of December 23, 2020

True or False: The AISC Code of Standard Practice provides two classifications for levels of work in architecturally exposed structural steel (AESS).
Answer:
False. Section 10 provides five levels (1, 2, 3, 4, and Custom). These levels are increasingly demanding and provide a method to better match expectations, applications, needs, and costs.


Week of December 16, 2020

True or False: If one were to check the strength of a bolt group subjected to an eccentric load in the plane of the faying surface, one might choose the instantaneous center of rotation method over the elastic method because the former is regarded as the more conservative approach.
Answer:
False. The instantaneous center of rotation method may be desired because it is more accurate than the elastic method. The elastic method is more conservative and can be easier to use for unique configurations not covered in the AISC Steel Construction Manual, Part 7.


Week of December 9, 2020

In the current AISC Specification, how is the safety factor, Ω, related to the resistance factor, ɸ?
a. it depends on the specific load combination
b. it varies as the live to dead load ratio varies
c. it is 1.5 divided by the resistance factor
d. it is a function of the limit state being considered
e. none of the above
Answer:
c.  For each limit state in AISC 360, one will find that Ω = 1.5 / ɸ.


Week of December 2, 2020

In the design of crane runway beams, which of the following contribute to side thrust?
a. runway misalignment
b.crane skew and steering
c. trolley acceleration and braking
d. all of the above
Answer:
d. According to AISC Design Guide 7: Industrial Buildings all of these items can produce horizontal forces on a crane runway beam.


Week of November 25, 2020

True or False: It is appropriate to use the steel properties from ANSI/AISC 360 Table A-4.2.1 for nonbuilding structures tha are designed for elevated temperatures as a normal service condition.
Answer:
False. The AISC Specification does list material properties at elevated temperatures in Appendix 4 Structural Design for Fire Conditions. However, the yield strengths listed are based on a 2% offset method because large deformations are acceptable in fire conditions. For design for sustained loading at elevated temperatures, values from a 0.2% offset method will be more appropriate.


Week of November 18, 2020

True or False: Local buckling effects need not be considered for encased composite members.
Answer:
True. In contrast, local buckling effects do need to be considered for filled composite members as defined in the AISC Specification.


Week of November 11, 2020

Which of the following design concepts can simplify design and construction, rendering a completely jointless deck, and may result in a more economical steel bridge design?
a. link slabs
b. high-performance steel (HPS)
c. continuous construction
d. self-propelled modular transporter (SPMT)
Answer:
a. link slabs


Week of November 4, 2020

True or False: The Code of Standard Practice requires a narrative on the contract documents to describe the lateral system and diaphragm elements.
Answer: 
True. Section 7.10.1 provides this requirement. It is necessary so the erector can properly plan the steel erection and the general contractor can properly coordinate any interdependence of the structural steel on non-structural-steel elements that provide lateral stability in the completed design.


Week of October 28, 2020

True or False: AISC and ACI tolerances for placement of anchor rods in concrete to receive structural steel are compatible in current codes.
Answer:
True. Anchor rod placement tolerances provided by these organizations used to be incompatible but these issues were resolved. Section 7.5.1 provides tolerances that work with ACI requirements and the base plate hole sizes provided in the AISC Steel Construction Manual.


Week of October 21, 2020

What is the basic erection tolerance for vertical plumbness of a column?
a. 1/300
b. 1/500
c. 1/600
d. 1/1000
Answer:
b. 1/500. More restrictive tolerances are specified in some cases; see Code Section 7.13.1.1.


Week of October 14, 2020

What does the "W" indicate in the ASTM designation "A709-50W" for bridge steel?
a. whitewash
b. weldable
c. waterproof
d. weathering
Answer:
d. weathering. Kudos to Shawn N. for quickly finding a typo in the original quiz posting!


Week of October 7, 2020

True or False: When a specific tolerance is not specified in the AISC Code of Standard Practice, that tolerance should not be interpreted to be zero.
Answer:
True. Section 1.10 states this specifically. The associated commentary clarifies that typical tolerances necessary for usual fabrication and erection are addressed and, where an additional tolerance is important for design, constructability, or another reason, it should be specified in the contract documents.


Week of September 30, 2020

My number may not be in your phone but you know how to connect with me. You may still fasten onto my old names even though I've got it all--and with a twist! Close your eyes tight and think. What am I?
a. ASTM F1554
b. ASTM F3125
c. ASTM A588
d. soda with a twist of lime
Answer:
d. ASTM F3125 is the ASTM specification for structural bolts. 


Week of September 23, 2020

True or False: Stress ranges that are completely in compression need to be investigated for fatigue.
Answer:
False. Fluctuations in stress that do not involve tensile stresses do not cause crack propagation and are not considered to be a fatigue condition. For a member subjected to compression only, cracks may initiate only in regions of high tensile residual stress and do not propagate because residuals stresses are relieved by the crack. Thus, stress ranges that are completely in compression do not need to be investigated for fatigue.


Week of September 16, 2020

The process by which individual plate girder flange sections are cut to the proper curvature from wider plates is referred to as:
a. heat-curving
b. cold-curving
c. cut-curving
d. cut-bending
Answer:
c. cut-curving


Week of September 9, 2020

ASTM F1554 is a common specification for which construction material?
a. turnbuckles
b. washers
c. structural bolts
d. anchor rods
Answer:
d. anchor rods


Week of September 2, 2020

Unless stated in the contract document or state specification, what level of surface preparation should be specified for a steel bridge that is using uncoated weathering steel (UWS) as the corrosion protection strategy?
a. Provide SSPC - SP10 (Near white metal blast cleaning) to all girders
b. Provide SSPC - SP6 (Commercial blast cleaning) to fascia girders only
c. Provide SSPC - SP15 (Green metal blast cleaning) to all girders
d. Provide SSPC - SP 5 (White metal blast cleaning) to all girders
Answer:
b, Provide SSPC - SP6 (Commercial blast cleaning) to fascia girders only


Week of August 26, 2020

True or False: The requirements in AISC 360 and AISC 341 are the same for buildings and nonbuilding structures similar to buildings.
Answer:
True. Although ASCE 7 may have different requirements for nonbuilding structures similar to buildings, neither AISC 360 nor AISC 341 differentiate between the two; the requirements apply equally to both.


Week of August 19, 2020

What are the three factors that must be present for constraint-induced fracture of welded details to occur?
a. Material constraint, high residual stress, presence of defect or crack-like geometry
b. Material constraint, live load stress, dead load stress
c. Overlapping welds, high residual stress, troll living under the bridge
d. Material constraint, cold temperature, presence of defect or crack-like geometry
Answer: 
a. Material constraint, high residual stress, presence of defect or crack-like geometry


Week of August 12, 2020

True or False: It is necessary to remove the ceramic insulator from a stud shear connector in composite construction.
Answer: 
True. Section 7.4.6 in AWS D1.1 states: “After welding, arc shields shall be broken free from studs to be embedded in concrete, and, where practical, from all other studs.” This is required for visual inspection of the weld.


Week of August 5, 2020

True or False: According to the RCSC Specification for Structural Joints Using High-Strength Bolts, the minimum bolt pretension for pre-installation verification is equal to 70 percent of the specified minimum tensile strength of bolts as specified in ASTM specifications for tests of full-size ASTM F3125 Grade A325 and Grade 490 bolts with UNC threads loaded in axial tension, rounded to the nearest kip.
Answer:
False. The minimum bolt pretension for Pre-Installation Verification is equal to 1.05 times the specified minimum bolt pretension required in Table 8.1, rounded to the nearest kip. (Refer to the RCSC Specification, available at aisc.org/specifications, Table 7.1)


Week of July 29, 2020

AASHTO has published a new Guide Specification for IRMs in steel bridges. What does “IRM” stand for?
a. Internationally Rumored Member
b. Internally Redundant Member
c. Internationally Renowned Member
d. Internally Revolved Member
Answer:
b. Inernally Redundan Member.


Week of July 22, 2020

True or False: Structural steel does not lose any of its metallurgical properties when it is recycled. 
True. The quality and properties of recycled steel are the same as virgin steel, making steel infinitely recyclable.


Week of July 15, 2020

In the Code of Standard Practice for Steel Buildings and Bridges (AISC 303-16), which of the following is a true statement regarding Architecturally Exposed Structural Steel (AESS)?
a. AESS level 1 is typically the most expensive.
b. AESS level 2 is recommended for a feature element viewed from further than 20 feet.
c. AESS level 4 is typically used for basic elements.
d. AESS levels refer to the finish type and do not correlate to cost.
Answer:
b. AESS level 2 is recommended for a feature element viewed from further than 20 feet.


Week of July 8, 2020

Concerning fillet welds, the more transverse the load direction:
a. the smaller the rupture surface and the lower the strength
b. the smaller the rupture surface and the higher the strength
c. the larger the rupture surface and the lower the strength
d. the larger the rupture surface and the higher the strength
Answer:
d. The transverse load orientation affords strength increase because the failure “plane” is a curved surface whose area is greater than the area defined by the effective throat extruded the length of the weld (the failure plane for longitudinally loaded fillet welds). See Design Guide 21 Section 3.5.7 for discussion.


Week of July 1, 2020

True or False: In building structures, corrosion protection is not required for steel that will be enclosed by a building finish, coated with a contact-type fireproofing or in contact with concrete.
Answer:
True. When enclosed, the steel is trapped in a controlled environment and the products required for corrosion are quickly exhausted. The surface condition of unpainted steel framing of longstanding buildings that have been demolished has been found to be unchanged from the time of its erection, except at isolated spots where leakage may have occurred. Even in the presence of leakage, the shop coat is of minor influence as indicated in Specification Commentary Section M3. A similar situation exists when steel is fireproofed or in contact with concrete. Accordingly, shop primer or paint is not required unless specified in the contract documents (refer to page 2-36 of the Manual).


Week of June 24, 2020

The intent of Specification Table J2.4 (minimum fillet weld size) is to ensure sufficient:
a. material quantity
b. heat input
c. weld visibility
d. time spent
Answer:
b. heat input. Assuming minimum weld sizes are made in a single pass (as the footnote in Table J2.4 indicates) there is a direct relationship between weld size and heat input. Sufficient heat input is required in order to achieve fusion and to slow cooling, preventing cracks that may otherwise occur. See Design Guide 21 Section 3.5.1 for more information.


Week of June 17, 2020

Cambering is clearly a better option for addressing deflection compared to shoring. However, for cases where beam shoring is required, the EOR should carefully consider the increased potential for ________. 
a. black eyes from shoring pole collisions.
b. shoring colors that clash.
c. slab cracking.
d. shoring that blocks views.
Answer:
Slab cracking. Allowing the dead load deflection to occur after the concrete has set will more likely result in slab cracks. This slab cracking may occur over the girders and can be addressed by providing negative reinforcement. This will make the cracking more distributed and less noticeable.


Week of June 10, 2020

What is the minimum length for a fillet weld without reduction of design strength?
a. The weld size
b. Twice the weld size
c. Four times the weld size
d. Eight times the weld size
Answer:
c. The strength of fillet welds not meeting this criterion may be calculated with size taken as one-quarter of the length, per AISC Specification J2.2c.


Week of June 3, 2020

When determining the amount of beam camber needed, it is common practice to specify a camber equivalent to ____ of the estimated simple-span deflections resulting from the dead load.
a. 90%
b. 80%
c. 70%
d. No reduction
Answer:
b. 80%. AISC Design Guide 3: Serviceability Design Considerations for Steel Buildings presents the 80% to account for end connection partial restraint. The magnitude of design camber will depend on several factors, including the framing condition and the method of screeding the concrete. Most engineers design for 80% and require the contractor to supply extra concrete and screed level. Some design-build contractors design for 100% and require flexible bar screeds be used to screed a uniform slab thickness.


Week of May 27, 2020

For which of the following joint types does the maximum fillet weld size apply, per AISC Specification section J2.2b? 
a. Lap
b. Butt
c. Inside corner
d. Tee
Answer:
a. The limits, based on material thickness, are intended to prevent melting away of exposed edges. Tee joints and inside corner joints do not have exposed edges. Butt joints cannot be joined with fillet welds. See Design Guide 21 Section 3.5.2 for images and further discussion.


Week of May 20, 2020

In order to avoid damage, the heat used to camber members should not exceed: 
a. 1,100 °F
b. 1,200 °F
c. 1,300 °F
d. 1,400 °F
Answer:
b. 1,200 °F .  The Specification for Structural Steel Buildings (ANSI/AISC 360, available at www.aisc.org/specifications) Section M2.1 conservatively limits the temperature of heated steels to 1,100 °F for ASTM A514 and ASTM A852 steels and 1,200 °F for other steels. The goal is to keep the steel temperature to less than the phase change temperature, which starts at approximately 1,300 °F.  The 1,200 °F limit allows for a variation of about 100 °F which is a common range achieved by experienced fabricators.  Also, note that heat camber is generally much more time consuming and labor intensive than cold cambering and therefore is rarely used.*

*We kind of goofed on this one, because the answer does depend on on type of steel and it also depends on if you are counting on the actual phase change temperature of steel of 1,300 °F. So, everyone except the 1,400 °F people get entered in this one!


Week of May 13, 2020

Tension-control bolts (ASTM F3125 Grade F1852 and Grade F2280) are limited to a maximum diameter of: 
a. 1 in.
b. 1 1⁄8 in.
c. 1¼ in.
d. 1½ in.
Answer:
c. 1¼ in. TC bolts were previously limited to a maximum diameter of 1 1⁄8 in., but this maximum has increased up to 1¼ in. per the new ASTM F3125 standard.


Week of May 6, 2020

When intermittent fillet welds are used to transfer calculated stress across a joint or faying surface, what is the minimum length of a fillet weld segment?
a. ¾ in.
b. 1 in.
c. 1¼ in.
d. 1½ in
Answer:
d. See AISC Specification J2.2b. (e).


Week of April 29, 2020

Which fillet weld geometry results in a higher strength-to-volume ratio?
a. ½-in. size × 12-in. length
b. ¼-in. size × 24-in. Length
Answer:
b. Strength, which is proportional to the product of length and size, is the same for each choice. Volume, which is proportional to the product of length and size squared, is half as much for choice b. BONUS: It should be noted that relative volume is an indirect indication of relative cost. Since labor, not material, dominates fabrication costs, the number of passes required to produce the weld can be a better indication of cost. Table 8-12 of the AISC Steel Construction Manual (www.aisc.org/manual) indicates that the ½-in. fillet weld will require four passes, whereas a ¼-in. fillet weld only requires one pass. The relative cost can be estimated as the product of the number of passes and their lengths.


Week of April 22, 2020

True or False: Per the new ASTM F3125 standard, ASTM A325 high-strength bolts are now specified and ordered as ASTM F3125 Grade A325 high-strength bolts.
Answer:
True. Since the new ASTM F3125 standard replaced six standards (ASTM A325, ASTM A325M, ASTM A490, ASTM A490M, ASTM F1852 and ASTM F2280), the term “grade” is used to help identify which specific product is required. It should be noted that the new grade names are the same as the names for the previous standards. This should facilitate a smooth transition. In order to help engineers in specifying bolts, Chapter J Section J3.1 of the 2016 AISC Specification for Structural Steel Buildings (ANSI/AISC 360, available at www.aisc.org/standards) establishes Bolt Groups as follows:

  • Group A—ASTM F3125/F3125M Grades A325, A325M, F1852 and ASTM A354 Grade BC
  • Group B—ASTM F3125/F3125M Grades A490, A490M, F2280 and ASTM A354 Grade BD
  • Group C—ASTM F3043 and F3111

So, rather than specifying a bolt as F3125 Grade A325 or F3125 Grade F1852 in your design documents, you would only need to specify a Group A bolt to encompass all bolt styles of the same strength level.


Week of April 15, 2020

Which of the following are not well suited for camber? 
a. Crane beams 
b. Spandrel beams 
c. Cantilevered beams 
d. All of the above
Answer:
d. All of the above. Camber is generally not recommended for these situations and should be carefully considered. It would be a good idea to consult with the contractor before doing so.


Week of April 8, 2020

True or False: Shear flow can be used to design the weld attaching the reinforcing to the existing steel member.
Answer:
True.


Week of April 1, 2020

True or False: Temperature crayons can be used to monitor the temperature of the base metal near the weld.
Answer:
True.


Week of March 25, 2020

When welding to loaded members, it is recommended to set the maximum interpass temperature to:
a. 300 °F
b. 600 °F
c. 800 °F
d. 1,100 °F
Answer:
a. 300 °F. Where appropriate, it’s recommended to set the maximum interpass temperature to 300 °F.


Week of March 18, 2020

True or False: The term “type” is used to differentiate between heavy-hex bolts and tension-control (TC) bolts.
Answer:
False. The term “style” is used to differentiate between heavy-hex bolts and TC bolts. “Type” refers to different steel compositions.


Week of March 11, 2020

Using intermittent welds to attach member reinforcement will:
a. Potentially lower welding costs
b. Decrease corrosion potential in exposed structures
c. Less weld shrinkage distortion
d. Both a and c
Answer:
d. Use of intermittent welds will potentially lower welding costs (should be confirmed with the fabricator performing the work) and should result in less weld shrinkage distortion.


Week of March 4, 2020

True or False: The 15th Ed. Manual includes both LRFD and ASD approaches for the design of structural steel members and connections.
Answer:
True. As indicated on page 2-9 of the Manual, the “two approaches are equally valid for any structure for which the 2016 AISC Specification is applicable” and there is “no preference stated or implied in the Specification.” Refer to page 2-9 of the Manual for additional information.


Week of February 26, 2020

Which end-loaded fillet weld geometry results in a higher strength-to-volume ratio?   
a. ¼-in. size × 24-in. length.
b. ¼-in. size × 48-in. length.
Answer:
a. Strength-to-volume ratios would be equal, were it not for the penalty on end-loaded fillet welds longer than 100 times their size per the 2016 AISC Specification J2.2d. Increases in length result in less uniformity in stress distribution, owing to complex effects of relative stiffnesses in addition to shear lag. The condition does not frequently occur in practice.


Week of February 19, 2020

Camber is typically induced in members: 
a. after bolt holes for member connections have been made to the member.
b. before bolt holes for member connections have been made to the member.
Answer:
a. After bolt holes for member connections have been made to the member. It is more difficult to run a cambered beam through a fabricator's automated process for creating bolt holes.


Week of February 12, 2020

True or False: All column base plates must be designed and fabricated with a minimum of four anchor rods, per the 2016 AISC Specification.
Answer:
False. This is required per OSHA regulations. See Section 1926.755(a)(1) of the 29 CFR Standards for Steel Erection. Note that posts (which weigh less than 300 lb.) are excluded from the four-anchor-rod requirement. OSHA requirements are summarized on page 2-6 of the 15th ed. Manual.


Week of February 5, 2020

For a fillet welded T-joint, what is the maximum gap allowed between pieces before the weld size must be increased by the gap size? 
a. 1/32 in.
b. 1/16 in.
c. 1/8 in.
d. 1/4 in.
Answer:
b. 1∕16 in., the same as the increment between weld sizes. See Clause 5.21.1 in AWS D1.1 and Design Guide 21 Section 3.5.11 for more information.


Week of January 29, 2020

True or False: The inelastic deformations required in common cold bending operations, such as for beam cambering, normally fall well short of the strain-hardening range
Answer:
True. Refer to the section on cold bending on page 2-35 of the Manual.


Week of January 22, 2020

Over-cambering a beam could result in:
a. Vibration issues 
b. Exposed studs 
c. Reduction in beam strength 
d. All of the above
Answer:
b. Exposed studs


Week of January 15, 2020

True or False: When two cut sections are welded back together to form the castellated section, a fillet weld is used to connect the two webs together.
Answer:
False. A full- or partial-penetration butt weld is used and is typically made from one side of the web, without prior beveling of the edges if the web thickness is relatively small.


Week of January 8, 2020

The line where the bolts are placed in angles is called:
a. Centroid line
b. Bolt line
c. Gage line
d. All of the above are correct
Answer:
c. Gage line.


Week of January 1, 2020

Which of the following terms does not belong with the others?
a. Weld backing
b. Backing strips
c. Weld tabs
d. Backing bars
Answer:
c. Weld tabs. A weld tab is not a backing bar but rather a piece of material that extends beyond the ends of a joint, on which the weld can be initiated or terminated. They are sometimes referred to a “runoff tabs.” 


2019 Answers

Week of December 25

True or False: The web thickness in an HP shape is equal to the flange thickness
Answer:
True. HP shapes are commonly used as pilings in foundations. Their heavy webs are made to resist the impact of the piledriving hammers.


Week of December 18

True or False: The critical stress in a fillet weld is considered to be a shear stress.
Answer:
True. Tension, compression and moments acting upon a fillet-welded joint are always resolved as shear in the weld throat—i.e., the least diagonal dimension.


Week of December 11

When calling out steel bars, it is a preferred practice to call out these members in what width increments?
a. 1/8-in. increments
b. 1/4-in. increments
c. 1/2-in. increments
d. 1-in. Increments
Answer:
b. This is stated in Part 1 of the 15th Edition Manual.


Week of December 4

True or False: Provisions for determining the lateral-torsional buckling strength of solid wideflange beams can be used for castellated and cellular beams if the cross-sectional properties are calculated at the gross section of the beam.
Answer:
True. Failure of castellated beams by lateral-torsional buckling is similar to that of solid wide-flange beams, with the holes having little influence.


Week of November 27

When detailing a steel beam, the drawings do not have to be drawn to scale in which dimension?
a. Longitudinal or length
b. Depth or height
c. Width
Answer:
a. Longitudinal or length.


Week of November 20

A single-sided CJP groove weld without a backing bar:
a. is impossible
b. should be avoided
c. is possible due to recent advances in robotic welding technology
Answer:
b. This situation should be avoided. These joints are seldom justifiable economically or structurally. They are expensive for several reasons: welder qualifications are appreciably more demanding, the resulting joints are not prequalified and preparation and fit-up are more exacting. Inspection of such welds can be difficult and potentially controversial when attempts are made to confirm acceptable complete penetration. Weld repairs are intricate and may damage other portions of the joint unless care is used.


Week of November 13

Surface finish quality of steel castings typically has the appearance of a(n):
a. Eggshell
b. Popcorn ceiling
c. Orange peel
d. Hot-rolled steel member
Answer:
c. Orange peel. Surface quality needs to be addressed for architecturally exposed structural steel (AESS) castings. Appropriateness of the surface finish will depend on many factors, including the casting process, coating system used, viewing distance and AESS category.


Week of November 6

ASTM A307 bolts are commonly referred to as:
a. Common bolts
b. Plain bolts
c. Soft bolts
d. Machine bolts
e. All of the above
Answer:
e. All of the above. These fasteners are not typically used in primary framing member connections.


Week of October 30

Which of the following is true regarding weathering steel?
a. Not all shapes will age/color the same
b. Standard electrodes will not weather the same as adjacent materials
c. A low corrosion rate can achieve a 120-year design life with nominal maintenance
d. All of the above
e. None of the above
Answer:
d. All of the above. Find out more about the benefits and challenges associated with weathering in the NASCC presentation “Building with Weathering Steel.”