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User Manual

This user manual provides detailed instructions on how to utilize the features of this spreadsheet effectively.

How to Use the Spreadsheet

  • The spreadsheet can be found here: post.xlsx.
  • Complete all cells highlighted in pink in the sheet tab “SampleCalc”.
  • Do not change any other values or add columns to the tables.
  • Print the “SampleCalc” sheet tab using a Portrait configuration.

Inputs Parameters

Element Description Input

  • Location: Specify the location of the column using the intersection of the gridlines where is located. For example, A-1 means the column is located at the intersection of gridlines A and 1.
  • Level: Defines the story where the element is located.
  • Label: Denotes the tag used for the post or mark.

Design Loads

  • P [lb]: Maximum compression over post due to ASD combinations.

Design Geometry Input

  • Post Size: Add the nominal section of the post
  • length[ft]: Enter the length of the post.
  • b[in]: rectangular dimension 1. Calculated based on the selected post size
  • a[in]: rectangular dimension 2. Calculated based on the selected post size
  • Category: Based on the post size, will be either dimensional lumber or timber/post

Material Properties Input

Input the relevant material properties:

  • Species and Commercial Grade: Add the wood species and the grade.
  • Fc: Compression parallel to Grain (psi). Taken from Table 4A, or 4D.
  • Emin: Minimum modulus of Elasticity (psi). Take from Table 4A, or 4D.

Wood Adjustment factors

  • \(C_D\) : Load duration factor. Recommended value: 1 for D+L combination. Refer to (2018 NDS, 2018) - Section 2.3.2 for more information.

  • \(C_M\) : Wet service factor. Recommended value: 1 for moisture content less than 19% for an extended time period. Refer to (2018 NDS, 2018) - Section 4.3.3 for more information.

  • \(C_t\) : Temperature factor. Recommended value: 1 for not exposed to temperatures larger than 150 F. Refer to (2018 NDS, 2018) - Section 4.3.4 for more information.

  • \(C_F\) : Size factor. Recommended value: 1 to be conservative. Refer to (2018 NDS, 2018) - Section 4.3.6 for more information.

  • \(C_i\) : Incising factor. Recommended value: 1 for not incised. Refer to (2018 NDS, 2018) - Table 4.3.8 for more information.

  • \(C_T\) :Buckling stiffness factor. Recommended value: 1 to be conservative.

  • \(c\) : c factor required to compute stability factor. Refer to (2018 NDS, 2018) - Section 3.7.1.5 for more information.

Calculations

The calculations are performed according to Section 3.7 of NDS 2018.

Output Results

If the DCR is less than 1.0, the status is PASS; otherwise, the status is FAIL.

Slenderness

  • \(DCR_{\text{Slenderness}} = \frac{(\frac{l_e}{d})}{50}\)

Compression capacity parallel to the grain

  • \(DCR_{\text{buckling}} = \frac{P}{Pc}\)

Bearing capacity parallel to the grain

  • \(DCR_{\text{support}} = \frac{P}{Pbearing}\)

References

2018 NDS. (2018). American Wood Council. https://awc.org/publications/2018-nds/

2018 NDS Supplement. (2021). American Wood Council. https://awc.org/publications/2018-nds-supplement/

ASCE 7-22. (2021). https://www.asce.org/publications-and-news/civil-engineering-source/article/2021/12/02/updated-asce-7-22-standard-now-available

Breyer, D. E., Cobeen, K. E., & Martin, Z. (2017). Design of Wood Structures ASD/LRFD Eighth Edition. https://shop.iccsafe.org/design-of-wood-structures-asd-lrfd-eighth-edition.html