Other Engineering Design

1. Glulam Lamination Widths for C_V Factor

   The program now uses a lamination width that you enter in Beam Input view as the “b” value in equation 5.3-1. Previously it conservatively used the member width, which is the maximum lamination width in most circumstances.

   1. Unknown Section

      If the member width is selected as Unknown, or a range of values, the program conservatively uses the member width as the maximum lamination width for initial selection of passing sections. When a section is selected for detailed design, you can then enter a different maximum lamination width and redesign.

   2. Default Value

      Each time a new member width is selected, the program defaults to using the member width as the maximum lamination width, and you must change it if you want a smaller lamination width.

   3. Use Member Width for C_V Factor

      A check box allows you to use the member width as the value b despite having a narrower lamination width (which could result in a smaller volume factor C_v.)This would ordinarily be done for glulam members constructed from remanufactured lumber, which require that the member width be used.

   4. Non-edge Bonded Laminations

      This input, which controls whether a factor is applied to the F_vy value , is now active only when the maximum lamination width is less than the member width, so that edge-bonding is possible.

   5. Output

      The maximum lamination width appears in the materials specification of the Design Check summary.

2. Glulam Shear Reduction Factor C_vr Factor

   NDS 2012 5.3.10 has been added to specify a shear reduction factor C_vr of 0.72 applied to the F_vx and F_vy values when members are notched or subject to impact loads. This is the same factor that was previously specified via notes to the glulam tables in the NDS Supplement - Table 5A, note 4; Tables 5A Expanded and 5B, notes 3

   1. Output

      This factor was previously applied to notched members only, and appeared under a column Cn for notches that included the shear reduction factor from tables 5A and 5B multiplied by the notching factor from NDS 3.4.3.2. This column has been renamed Cn*Cvr The explanatory note below the table has been adjusted accordingly.

   2. Impact Loads

      Previously, the program did not apply this factor for impact loading. It is now applied to any load combination that includes impact loads, and if it is the critical load combination, the factor appears in the renamed column Cn*Cvr .

3. I-Joist Lateral Support

   The disabled input field for lateral supports for I-joists now shows the Fully Supported at top and bottom, rather than At Supports, to comply with NDS 7.3.5 stating that the C_L factor is 1.0 only if fully supported on the compression flange, and in the absence of design procedures in Sizer for I-joist lateral support. The lateral support appears in the beam drawing, but not in the material specification in the design check output.

4. Flat Use Factor for Timbers

   The program has implemented the change to the Adjustment Factors to Table 4D in the NDS Supplement, such that the existing component of the size factor C_F that is applied to the wide face of members has been renamed C_fu, the flat-use factor. In the Modification Factors table in the design results, the number that used to appear in the Cf column for members loaded on the wide face now appears in the C_fu column.

5. Default Deflection Limit for Walls and Columns

   The default deflection limit that is shipped with new installations of Sizer or occurs when you select Restore ‘factory’ settings has been changed from L/180 to L/120, to conform with IBC table 1604.3 for flexible finishes (such as drywall).

6. Repetitive Member Factor for Wind Loads On Walls ( Change 132)

   The checkbox in Column view that allows you to specify special repetitive member factors for wind loads on walls has been changed as follows

   1. AF&PA Reference

      The reference to AF&PA has been changed to AWC.

   2. IBC Reference

      The reference to IBC 2306.2.1 has been removed, as this provision was dropped for the 2009 IBC.

   3. Rewording

      The text has been reworded to ask whether you want to apply the factor, not just whether the wall is sheathed in a way to allow it.

7. New Checks for Bending and Axial Compression

   New conditions, 3.9-4, 15.4-2 and 15.4-4 have been added to the equations for combined axial and bending resistance. Because Sizer restricts columns to uniaxial bending plus axial forces, and beams do not have axial forces, these equations are not required by Sizer because the conditions are met by the main equations, 3.9-3, 15.4-1, 15.4-3 and the other checks beneath these equations.

   Note that according to the commentary to these clauses and the restrictions to the f_c < f_cE1 and f_b1 < f_bE checks indicate this equation is not required for columns that are loaded only in the flatwise direction, so does not apply to columns loaded with edgewise loads.

   As a consequence, no design changes were necessary, but the addition of the new clause 15.4-2 required renumbering of previous 15.4-2 to 15.4-3. This is reflected in the Analysis vs Design table of the Design Check summary, and in the load combination notes below.