© 2009 Jonathan Ochshorn.
Directions: Enter values for species, grade, cross section, and bolt geometry (for regular bolt grid only; staggered bolt geometries cannot be used in this calculator). Enter "load of shortest duration" to adjust allowable stresses for "duration of load." For live and dead load only, enter "live load." Wet service conditions only matter for allowable shear (in tear-out calculations). Bolts, if any, are normally inserted through the smaller cross-sectional dimension, t (in which case the question, "bolt length = t?" is answered, "yes"). Cross sections are checked for tension capacity on the net area and, if desired, for row and group tear-out. It is assumed that the tension force is applied parallel to grain. Select either the 2005 or 2012 version of the National Design Specification (NDS); revised Southern Pine design values for dimension lumber (effective June 1, 2013) are included with the 2012 NDS.
Bolt geometry and bolt capacity (see Fig. 1) are not checked; however, bolt spacing and end/edge distances that do not comply with NDS-2005 guidelines are noted. Southern Pine allowable stress values for dimension lumber are approximate, so that the so-called "size factor" (included in published Southern Pine values, but left out of the allowable stress values for other species) can be considered in a consistent manner.
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More detailed explanations and examples can be found in my text.
Disclaimer: This calculator is not intended to be used for the design of actual structures, but only for schematic (preliminary) understanding of structural design principles. For the design of an actual structure, a competent professional should be consulted.
First posted August 6, 2009 | Last updated March 27, 2014