6. What two characteristics definean HP-shape?

7. Which of the following definitionsgenerally describes a castellatedbeam?a. a beam that has been made

composite with a cast-in-placeconcrete slab above

b. a beam with web holes that hasbeen fabricated from a shallow-er shape

c. a beam that is cantilevered overthe top of a column below

d. a plate girder with periodictransverse stiffening

8. Two limit states for concentratedforces on flanges in LRFDSpecification Chapter K are localflange bending and compressionbuckling of the web. The former isapplicable only when the concentrat-ed flange force is tensile and the lat-ter is applicable only when a pair ofcompressive forces at oppositeflanges would tend to pinch the web,True or False?

9. Structurally, is there a differencebetween a 1/2 H 4 bar and a 1/2 H 4plate?

10. Square, rectangular, and circu-lar hollow structural sections (HSS)are appropriately ordered to whichof the following ASTMSpecifications?a. A6/A6Mb. A500c. A36d. a or c

Modern Steel Construction / April 1996

STEEL QUIZ, A MONTHLY FEA-TURE IN MODERN STEELCONSTRUCTION, allows youto test your knowledge of steeldesign and construction.Unlessotherwise noted, all answers canbe found in the LRFD Manual ofSteel Construction. To receivea free catalog of AISC publi-cations, circle #10 on thereader service card in theback of this magazine.

Correction:

Thank you to Larry Kloiber ofLeJeune Steel Company for pointingout a technical error in the answer toQuestion 5 in the February 1996 SteelQuiz. A weld placed between platesforming an angle less than 60 degreesis considered to be a partial joint pene-tration groove weld (hence the Z-lossfactor), not a fillet weld as the questionand answer indicated.

Questions:1. When must the bolt/nut assemblybe treated as a manufacturedmatched assembly?

2. For a cambered beam spanning 40ft, what tolerance is specified on thecamber ordinate in the AISC Code ofStandard Practice?

3. The term matching weld metal isused in LRFD Specification SectionJ2. To what are these weld metalsmatched and in what document arethe matching weld metals defined?

4. An ASCE 60 pound crane railweighs 20 pounds per foot, True orFalse?

5. Which of the following statementsis false?a. all fillet welds that conform to

the requirements of AWS D1.1are prequalified

b. small burrs do not reduce theslip resistance of bolted connec-tions

c. galvanized faying surfaces inslip-critical connections may beroughened by means of powerwire brushing

d. a flare weld is a special type ofpartial-joint-penetration grooveweld

S T E E L Q U I Z

7. b. Generally speaking, a castellat-ed beam is one that is fabricatedfrom a shallower shape by cuttinglongitudinally in a zig-zag-like pat-tern, separating and longitudinallyoffsetting the resulting sections, andrewelding them back together toform a deeper shape of approximate-ly the same average weight per foot.

8. True. From LRFD SpecificationSection K1.2, local flange bendingapplies only to tensile flange forces.From LRFD Specification SectionK1.6, compression buckling of theweb applies only to a pair of pinch-ing compressive forces at oppositeflanges (termed a pair of compres-sive single-concentrated forces or thecompressive components in a pair ofdouble-concentrated forces; seeLRFD Specification CommentarySection K1.1 and LRFD Manualpage 10-35).

9. Structurally no; furthermore,plate is becoming a universallyapplied term today. However, thehistorical classification system forsuch structural material would sug-gest the following physical differ-ence: all four sides of the 1/2 H 4 barwould be rolled edges, i.e., the millrolled it to that thickness and width;the 1/2 H 4 plate might have been cutfrom a 1/2-in. plate of greater width.

10. b. ASTM A500 is appropriatewhen specifying square, rectangular,and circular HSS. Note that pipe-size rounds (P, PX, and PXX) arealso available in material meetingASTM A53 grade B.

Modern Steel Construction / April 1996

S T E E L Q U I Z

Answers:1. The RCSC Specification Comm-entary indicates two cases in whichbolts and nuts must be treated as amanufactured matched assembly:when bolts are galvanized (SectionC2) and when tension-control boltsare specified (Section C8). In the for-mer case, because nut-thread over-tapping to accommodate the addedthickness of galvanizing may reducethe nut stripping strength, ASTMA325 requires that the galvanizedassembly be lubricated and tested bythe manufacturer to ensure ade-quate rotational capacity. In the lat-ter case, some of the negativeaspects of this torque-controlledinstallation method are minimizedthrough good quality control in thematched assembly.

2. AISC Code of Standard PracticeSection 6.4.5 indicates that, formembers less than 50 ft in length,the camber tolerance is minuszero/plus 1/2-in. Note that it furtherindicates that members receivedfrom the rolling mill with 75 percentof the specified camber require nofurther cambering.

3. Weld metals are matched to thesteel grade being welded. Matchingweld metals are specified in AWSD1.1-94 Table 4.1.

4. True. Crane rails are designatedby their nominal weight per yard.Therefore, an ASCE 60 pound cranerail weighs 20 pounds per foot.

5. c. Power wire brushing polishesthe galvanized surface, rather thanroughening it; see RCSCSpecification Commentary SectionC3. Parts a, b, and d are true; seeAWS D1.1-94 Section 2.7.1, RCSCSpecification Commentary SectionC3, and AISC LRFD Manual page 8-127, respectively.

6. As defined in ASTM A6/A6MSection 3.1.2.4, HP-shapes (common-ly used as bearing piles) are wide-flange shapes whose ... flanges andwebs are of the same nominal thick-ness and whose depth and [flange]width are essentially the same.