Errata for “Structural Steel Design,” Fourth Edition, by Jack C ...

Errata for “Structural Steel Design,” Fourth Edition, by Jack C. McCormac
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Updated 03-Oct-12
Chapter 4
1. On page 102, in the first paragraph, the reference to the AISC Specification should be
D1 (not D.1).
2. On page 106, Example 4-1, in the calculation for “min Ag”, a value of 0.380 (not 0.520)
should be used in the estimated area for the bolt holes. The subsequent value for “min
Ag” should be 9.09 in 2 (not 9.65 in 2 ). The value 0.380 is noted in the first paragraph of
page 106, however a value of 0.520 is used in the calculation.
3. On page 111, Example 4-3, the problem states that the connection of the tension
member is through the channel flanges. However, in the calculation for U (on page 112),
the x distance is taken from the back of the channel web to the centroid of the channel
implying that the connection plane is to the web and not the flange.
To determine U for a connection to the flanges, an approximate value y (i.e. the
distance from the top of the top flange to the centroid of the half-channel) can be
determined assuming the flange and web are rectangles. Based on such an assumption,
the approximate location of y for the centroid of the half channel is 2.17" below the top
of the top flange giving a value for U = 1 - 2.17/6 = 0.638. As a result, the member is not
adequate for the given loads based on tensile rupture strength.
In the given problem statement if the connection is to the web, then the calculation
shown for U can be preserved and the section is adequate.
Figure 4-02 may be retained in the example. This figure shows the location of the
bolt holes that are used for the tie plates and the corresponding gage distance which is
used in the example for the design of the tie plate. However, these bolt holes would not
be the holes for the bolted connection to another member.
Chapter 6
1. On page 198, Problem 6-21, the steel should be specified as 36 ksi, not 50 ksi. Angles
are usually furnished in A36 steel. The answer furnished by the author is based on 36
ksi.
Chapter 10
1. On page 297, Example 10-1 (Part b), the positive moment values shown in the moment
diagram are based on the ASD critical load combination and should be 263 (not 600),
295 (not 695), and 233 (not 446).
Furthermore, on page 297, the values of moment used in the equation to determine
the maximum positive moment for design should be 295 (not 695). The resulting
maximum positive moment for design should be +345.5 ft-k (not +745.5 ft-k).
2. On page 321, Example 10-7, for the LRFD solution, the second term in the equation for
wux should be “1.6 S” not the number “1.65.” The following calculations are correct.
3. On page 321, Example 10-7, for the ASD solution, the second term in the equation for
wax should be “S” not the number “5.” The following calculations are correct.
4. On page 329, in the fourth line of the first paragraph, the term “φcPp” should be replaced
with “φc0.85f’c” and the term “Pp/Ωc” should be replaced with the term “0.85f’c/Ωc.”

5. On page 329, the equations for A1 that follow the first paragraph should be corrected as
follows.
A1 = Ru/φc0.85f’c A1 = ΩcRa/0.85f’c
6. On page 329, Example 10-10, the value of Fyw used to check web local yielding should
be 50 ksi (the steel for the beam) not 36 ksi (the steel for the plate). The resulting value
for Rn should be 272.9 kips (not 196.5 kips).
Furthermore, the value used for Rn in the subsequent LRFD and ASD calculations on
page 330 should be 272.9 kips (not 196.5 kips). φRn should be 272.9 kips (not 196.5
kips) and Rn/Ω should be 181.9 kips (not 131 kips).
The A36 steel is specified for the plate steel. The steel used for the beam should be
A992 (Fy = 50 ksi).
7. On page 330, Example 10-10, the value of Fyw used to check web crippling should be 50
ksi (the steel for the beam) not 36 ksi (the steel used for the plate). The resulting value
for Rn should be 261.3 kips (not 221.7 kips).
Furthermore, the value used for Rn in the subsequent LRFD and ASD calculations on
page 330 should be 261.3 kips (not 221.7 kips). φRn should be 196.0 kips (not 166 kips)
and Rn/Ω should be 130.6 kips (not 111 kips).
The A36 steel is specified for the plate steel. The steel used for the beam should be
A992 (Fy = 50 ksi).
8. On page 331, in the LRFD and ASD calculations for thickness, the value of Fy should be
50 ksi (not 36 ksi) since the steel used for the beam should be A992 (Fy = 50 ksi). The
resulting required plate thickness should be 0.758” for LRFD and 0.772” for ASD. As a
result, both calculated thicknesses are less than the flange thickness of 0.810” for the
W18 x 71.
Furthermore, the area A1 provided by the flange is 8 x 7.64 = 61.12 in 2 and is less
than the required area A1 of 75.8 in 2 (LRFD) or 78.43 in 2 (ASD) computed on page
329.Thus the stresses in the concrete would exceed the allowable stresses if the flange
alone were used for bearing without a bearing plate.
Chapter 11
1. On page 346, in the notation for AISC Equation C2-6b, the term for “first-order interstory
drift due to ∑H lateral forces” should be “ΔH” (not “ΔH”). The error occurs in the equation
and in the following list where the factors are defined.
2. On page 354, Example 11-5, near the bottom of the page in the LRFD calculations for
the equation ½ρPr + (9/8)(bxMrx + byMry) ≤ 1.0, the value used for Pr should be “244” (not
“???3.244”).
Furthermore, the value used for by should be 2.32 x 10 -3 (not (2.3 x 10 -3 ).
The answer 0.742 appears to be correct.
3. On page 360, Example 11-9, in the given information, the notation ∑Pu = 5000 k should
be ∑Pnt = 5000 k, the notation ∑Pex = 40,000 k should be ∑Pe2x = 40,000 k, and the
notation ∑Pey = 5000 k should be ∑Pe2y = 5000 k.
Furthermore, on page 361, the value used for Pr in the calculation for Pr/Pc should be
286 (not 250) and the result of the calculation should be 0.238 (not 0.208).
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Furthermore, on page 361, the value used for Pr in the calculation for B1x should be
286 (not 250). The result of the calculation appears to be correct.
Furthermore, on page 361, the value used for Pr in the calculation for B1y should be
286 (not 250). The result of the calculation should be 0.215 (not 0.213).
4. On page 362, Problem 11-10, the value for Cmx should be 1.0 (not 0.85). A value for Cmy
is not required.
5. On page 343, at the end of the second paragraph for Section 11.3, the notation for the
secondary moment produced due to sidesway should be PntΔ (not Mlt).
6. On page 362, Problem 11-10, Cmx = 1.0 (not 0.85) and Cmy (listed as 0.85) is not
required.
Chapter 12
1. On page 388, Example 12-1, the reference following the calculation for the effective area
Ae should be AISC Spec. J4.1 (not AISC Spec. J4.16).
2. On page 396, Example 12-4, the values actually used in the example for PD is 30 kips
and for PL is 50 kips (not 50 kips and 30 kips, respectively, as listed in the given
information).
3. On page 397, Example 12-4, in the calculation for the bearing strength of the 6 bolts, the
coefficient used to determine the bearing strength Rn should be 1.2 (not 1.5) since
deformation around the bolt holes was listed as a design concern in the problem
statement. The resulting value for Rn should be 347.2 kips (not 434 kips).
Furthermore, the value used for Rn in the subsequent LRFD and ASD calculations on
page 398 should be 347.2 kips (not 434 kips). φRn should be 260 kips (not 326 kips) and
Rn/Ω should be 173.6 kips (not 217 kips).
Chapter 13
1. On page 420, Example 13-4, the problem states that deformations at bolt holes at
service loads is not a design consideration. Consequently, the second part of the
equation used to determine the nominal bearing strength should be “3.0 d t Fu” (rather
than “2.4 d t Fu”).
Chapter 14
1. On page 466, Table 14.2, the minimum size of fillet welds is based on the material
thickness of the “thinner” (not “thicker”) part joined per AISC Table J2.4.
2. On page 471, the calculations to check the tensile rupture strength of the connecting
elements should be as follows.
From Table 3.2 (p. 75 of the textbook), Case 4:
1.5w = 1.5(8) = 12” > ℓ = 10” > w = 8”, thus U = 0.75
An = (3/4)(10) = 7.5 in 2
Ae = U An = 0.75 (7.5) = 5.625 in 2 (not 10.5 in 2 )
Rn = Fu Ae = 65 (5.625) = 365.6 kips (not 682.5 kips)
Furthermore, the value used for Rn in the subsequent LRFD and ASD calculations on
page 471 should be 365.6 kips (not 682.5 kips). φRn should be 274.2 kips (not 511.9
kips) and Rn/Ω should be 182.8 kips (not 341.2 kips).
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3. On page 476, in the paragraph following the equation for FwAw/Ω, the first line should
read “For LRFD with E70 electrodes, φRn = (0.0199)(70) = 1.39 k/in.” The φ term is
omitted in the text.
4. On page 481, Example 14-7, the length of the slot weld is determined to be 6” (LRFD)
and 6.5” (ASD). However, the maximum length of the slot weld is 5”.
5. On page 493, in the first line of the second paragraph, the words “and 14-13” should be
deleted. There is no Example 14-13 in the text.
6. On page 493, in the first line of the third paragraph, the words “two W sections” should
be replaced with “two plates.” Example 14-12 specifies two plates.
Chapter 15
1. On page 519, Example 15-3, under “Select Weld B for column,” the thickness of the
column flange for the W14 x 61 is 0.645” (not 0.545”).
Furthermore, in the last line of Example 15-3, where the angles are specified, the
angle thickness should be 3/8” (not 5/16”). A minimum angle thickness of 3/8” was
determined earlier in the example.
2. On page 522, in the next to last paragraph for Example 15-4, the 5 inch dimension was
determined from page 10-101 of the AISC Manual (not page 10-10).
3. On page 524, Example 15-5, under the check for local web yielding, the reference
should be to AISC Equation J10-3 (not AISC Equation J10-2).
3. On page 525, the angle that is specified is L8 x 4 x 7/16 x 0 ft 8 in for both LRFD and
ASD. However, this angle thickness is outside the range of available angle thicknesses
listed in AISC Table 10-6 for the 8 x 4 angle. The angle thickness should be 3/4” (not
7/16”).
Furthermore, based on an examination of Table 10-6 with N = 1½”, the required
angle thickness is 3/4” for LRFD and ASD.
Furthermore, in the ASD calculations to determine the angle thickness t, the ASD
notation should be Rn/Ω (not Rn/φ).
4. On page 531, rule number 2 should be stated as follows: “The stiffener thickness should
not be less than one-half the thickness of the flange (tf/2) or half the thickness of the
moment connection plate delivering the concentrated load, and not less than the width
divided by 15.” (Per AISC Specification J10.8.)
5. On page 532, Example 15-7, in the ASD calculations for web local yielding, the
comparison of Rn/Ω = 225.2 kips should be with Ca = 150 kips (not 140 kips).
6. On page 533, Example 15-7, the calculation of the min t of stiffeners should include a
factor of 2 in the denominator since a stiffener is located on each side of the beam web.
The resulting calculated minimum thickness should be 0.179” (not 0.358”).
However, the minimum thickness required by the AISC Specification must be half the
flange thickness, and tf/2 = 0.605/2 = 0/303”, so the 3/8” thickness indicated is correct.
Furthermore, the minimum weld size required by Table J-2.4 is based on the
thickness of the thinner part, in this case the 3/8” plate, not the W12 x 87 column web
thickness of 0.515”. However, the listed weld size of 3/16” is correct.
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7. On page 535, Problem 15-11, in the answer, the connection is made to the column (not
girder).
Chapter 16
1. On page 555, the notation for the lower bound moment of inertia should be Ilb (not I) for
AISC Commentary Equation C-I3-1.
2. On page 556, Example 16-3, the notation for the factored moment for the LRFD method
should be Mu = 670 ft-k (not Ma = 670 ft-k).
3. On page 558, Example 16-3, under “Design of studs,” the equation for the “Total no. of
connectors required” should be corrected as follows:
Total number of connectors required on each side of the point of maximum moment
= ∑Qn/Qn = 494/21.2 = 23.2
Use 24 ¾” studs on each side of the point of maximum moment (which is C/L here).
4. On page 559, Example 16-3, the concluding statement should be corrected to read “Use
W18 x 46 with forty-eight 3/4” headed studs.”
5. On page 565, Example 16-5, the value for the moment of inertia I used in the
denominator for the calculation of ft under “stresses after concrete hardens” should be
1127 (not 1129) as determined earlier in the example.
Furthermore, the value for ft should be 42.93 ksi (not 42.86 ksi) and the “Total ft”
should be 72.83 ksi (not 72.76 ksi).
Chapter 17
1. On page 576, in the sixth line of the next to the last line of the paragraph beginning with
the words “The original reason for limiting . . .” the notation should be Es (not Fs).
2. On page 577, in the second line of Note 2, the notation should be 2.26√E/Fy (not
2.26√F/Fy).
3. On page 579, Example 17-1, the calculated value for Ec should be 3.2665 x 10 3 ksi (not
3.410 x 10 3 ksi).
Furthermore, on page 579, the calculation for Ic omits the deduction for the
reinforcing steel. Thus the calculation for Ic should be shown as follows.
Ic = (1/12)(20)(20) 3 – 195 – 4(1.0)(7.5) 2 = 12,913 in 4 (not 13,138 in 4 )
Furthermore, on page 579, using the corrected values for Ec and Ic, the calculated
value for EIeff should be 17.632 x 10 6 k-in 2 (not 18.173 x 10 6 k-in 2 ).
Furthermore, on page 580, using the corrected value for EIeff, the calculated value for
Pe should be 8392.2 k (not 8650 k).
Furthermore, on page 580, using the corrected value for Pe, the calculated value for
Pn should be 2137.3 k (not 2145 k).
Furthermore, the value used for Pn in the subsequent LRFD and ASD calculations on
page 580 should be 2137.3 kips (not 2145 kips). φPn should be 1603.0 kips (not 1608.8
kips) and Pn/Ω should be 1068.6 kips (not 1072.5 kips).
4. On page 581, Example 17-2, in the calculation of C3, the value used for Ac should be
123.1 in 2 (not 12 x 12). Thus, the value for C3 should be 0.8903 (not 0.85).
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Furthermore, on page 581, using the corrected value for C3, the calculated value for
EIeff should be 17.205 x 10 6 k-in 2 (not 17.026 x 10 6 k-in 2 ).
Furthermore, on page 581, using the corrected value for EIeff, the calculated value for
Pe should be 4606.3 k (not 4558 k).
Furthermore, on page 581, using the corrected value for Pe, the calculated value for
Pn should be 1217.3 k (approximately the value of 1217 k shown).
5. On page 582, the second equation for Vn should be corrected as follows.
Vn = 2√f’c b d + Vst
The last term should be Vst (shear strength of the steel) not Ast (area of the steel).
6. On page 586, Problem 17-7 (c), the answers should be 671 k, 448 k (not 671 k, 446 k).
Chapter 18
1. On page 595, the equation for Zfurnished should read as follows.
Zfurnished = 2Af(h/2 + tf/2) + 2[(h/2)(tw)(h/4)]
2. On page 595, the equation for Mu/φbFy should read as follows.
Mu/φbFy = 2Af(h/2 + tf/2) + 2[(h/2)(tw)(h/4)]
3. On page 595, in the equation for the flange area Af, the values tw shown in the
denominator should be tf so that the equation reads as follows.
Af = Mu/φbFy(h + tf) – twh 2 /4(h + tf)
4. On page 597, when checking for compactness of the flange plates, the ratio bf/2tf should
be compared with the value of 0.38 (E/Fy) ½ = 10.79.
5. On page 605, the value φvVn shown in the denominator of AISC Equation G3-3 should
be Vc. The value for Vc is φvVn for LRFD and Vn/Ωv for ASD.
6. On page 609, Problem 18-1, a live load L = 3 k/ft (not 4 k/ft) is used in the solution by the
author.
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