Structural Elements

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# Structural Elements for Architects and Builders, 2nd Edition

Jonathan Ochshorn

Errata for Second Edition

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**p.135** Example 3.3. Problem solution, beginning with step 2*d*: The following corrections reflect the use of "green" sizes, rather than "dry" sizes, for calculations involving timbers.

Step 2*d*:

*d* = 9.5 in. rather than 9.25 in.
*F*_{}, with value of *d* changed, is now 4135.7 psi
*A*, with *F*_{} changed, is now 2.87
*B*, with *F*_{} changed, is now 4.50
*C*_{p}, with *A* and *B* changed, is now 0.934.

Step 3: *F'*_{}, with *C*_{} changed, is now 1075 psi.

Step 4: Capacity—with *F'*_{} changed and area changed from 9.25 × 9.25 = 85.56 in^{2} to 9.5 × 9.5 = 90.25 in^{2}—is now 96,679 lb = 96.7 kips.

Step 5 is now "Check capacity: since the capacity of 96.7 kips ≥ governing load combination of 90 kips, the column is OK. The value of *C*_{p} = 0.934 indicates that buckling has reduced the column's allowable compressive stress to 93.4% of its 'crushing' strength."
Posted April 5, 2020

**p.143–145** Example 3.6. Problem solution, step 4: The equation for *C*_{F} should be *C*_{F} = (12/19)^{1/9} = 0.95 (no change in the answer). Step 7: The actual *S*_{x} should be 855.6 in^{3} (the conclusion is the same). Step 10: The actual area should be 263.3 in^{2} (the conclusion is the same). Steps 12, 13: The moment of inertia, *I*_{x} should be 8342 in^{4} (the conclusion is the same).
Posted Nov. 6, 2019

**p.209** Table A-3.16: Although the 2012 NDS reduced the dry dressed sizes of certain timbers by subtracting 3/4 in. or 1 in. from some of the nominal dimensions, the green minimum sizes remained the same, with only 1/2 in. subtracted from the nominal dimensions. In such cases, all structural calculations use the green sizes, even when the dry minimum dressed dimensions are smaller. The appendix sizes in this table therefore need to use the "green" dimensions for structural calculations of *C*_{F}S_{x}, rather than the "dry" dressed dimensions. Revised Table A-3.16 is here.
Posted Nov. 6, 2019; revised Feb. 14, 2020

**p.206–207** Table A-3.12, parts B and C: Although the 2012 NDS reduced the dry dressed sizes of certain timbers by subtracting 3/4 in. or 1 in. from some of the nominal dimensions, the green minimum sizes remained the same, with only 1/2 in. subtracted from the nominal dimensions. In such cases, all structural calculations use the green sizes, even when the dry minimum dressed dimensions are smaller. The appendix sizes in this table therefore need to show the "green" dimensions used for structural calculations, rather than the "dry" dressed dimensions. This affects not only the "actual" dressed sizes, but also areas, section moduli, and moments of inertia. Revised Table A-3.12 is here.
Posted Nov. 6, 2019; revised Feb. 14, 2020

**p.121** Delete redundant last paragraph. Add the following note about timber sizes: "Although the 2012 NDS reduced the dry dressed sizes of certain timbers by subtracting 3/4 in. or 1 in. from some of the nominal dimensions, the green minimum sizes remained the same, with only 1/2 in. subtracted from the nominal dimensions. In such cases, all structural calculations use the green sizes, even when the dry minimum dressed dimensions are smaller. The appendix sizes show whichever dimensions are to be used for structural calculations."
Posted Nov. 6, 2019

**p.394** Equation 5.30. The coefficient in the numerator of the equation, 0.2, should be changed to 0.02.
Posted February 18, 2019

**p.410** Table A-5.11. Values in this table were incorrectly copied and pasted from Table A-5.10. The correct values are as follows:
*f'c* (psi) |
bar number ["in-lb" designation, with nominal diameter (in.) = bar number/8] |

3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 14 | 18 |

3000 | 9 | 11 | 14 | 17 | 20 | 22 | 25 | 28 | 31 | 38 | 50 |

4000 | 8 | 10 | 12 | 15 | 17 | 19 | 22 | 25 | 27 | 33 | 43 |

5000 | 7 | 9 | 11 | 13 | 15 | 17 | 20 | 22 | 24 | 29 | 39 |

Posted February 18, 2019

**p.362** Example 5.4. Problem solution, step 1: "From Appendix Table 5.4" should be changed to "From Appendix Table A-2.7"; and step 4: Figure 5.26 (*b*), the bottom line calculation units should be "ft-kips" rather than "ft=kips."
Posted October 26, 2017

**p.288** Table A-4.2. The right-hand column, under "tension" should be changed to reflect the actual available strength limit state for rupture as shown below:

Posted February 14, 2017

**p.18** Example 1.3. In Step 3, the equation for moment equilibrium should be written with the term 10(*Ha*) instead of just *Ha*. The calculations and solutions are correct as is.
Posted October 21, 2016

**p.289** Table A-4.3. The designation in the first column listed as W6x92 should be W6x9^{2} — in other words, the "2" is a footnote.
Posted August 11, 2016

**p.143** Example 3.6. In the problem solution, step 3, the allowable bending stress, F_{b}, is incorrectly given as 850 psi. The correct value (under the "beams and stringers" classification) is F_{b} = 675 psi. All the calculations that follow are correct.
Posted July 27, 2016

**p.341** Figure 5.4. In the last line of the caption, the numerator and denominator of distance *A* should be reversed, so that *A* = (*D + s*)/[2sin(θ/2)]
Posted June 2, 2016

**p.352** On the second line (directly after "…the upper limit of 8% prevents overcrowding of steel bars within the concrete formwork."), add: "Because longitudinal column reinforcement is typically spliced—and therefore doubled in area—where an upper column is cast above a lower column (see Figure 5.53), it is common to limit the maximum reinforcement ratio to 4%."
Posted May 11, 2016

**p.121** Delete the last paragraph on this page ("Following are the current rules... 1960s or earlier.") as it repeats the information in the preceding paragraph.
Posted March 17, 2016

**p.208 and p.327** Tables A-3.15 and A-4.17. Flip the image of the cantilevered beam so that it corresponds to the image of the concentrated load shown in the same tables (i.e., for a concentrated load on the *left*, the fixed constraint must be on the *right*).

Posted March 4, 2016

**p.70** Figure 2.5 Live load reduction coefficient graph. The two curves should be labelled as beams (for the upper curve) and columns (for the lower curve). Dotted lines should be added to the "beam" curve connecting it with the lower, 0.4, limit for cases where a beam supports multiple floors, and from the "column" curve, connecting it with the upper, 0.5, limit for cases where a column supports only one floor (or roof), as shown below in red.

Posted October 30, 2015 (revised Dec. 29, 2015)

**p.306** Table A-4.9 Shear Lag Coefficient, U. The bottom cells of the table should be adjusted as follows:
Bolts connecting single **and double** angles (L). |
*U* = 0.80 where one leg of the angle is connected with at least 4 bolts per line.
*U* = ~~0.75 where one leg~~ **0.60 where one leg** of the angle is connected with ~~2 or~~ 3 bolts per line. **For less than 3 bolts, use the equation in note 1**. |

Posted Jan. 27, 2016