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Sizer 8.2 - Design Office 8 Service Release 2 - October 9, 2009
This version provides the following corrections and improvements to the program:
For version 7 which updated the program to NDS 2005 from 2001, the column database file, Glulam-Balanced (glulamcomb.cwc) and the Beam database file, Glulam-Uniform (glulamunif.cwb) were not updated along with the rest of the database files. As a result, the list of combinations and certain design properties were from the NDS 2001 Supplement, Table 5A rather than the revised properties published in the NDS 2005 Supplement. Comparing 2005 to 2001, all allowable shear stresses were increased typically by about ten percent, so shear design using these materials will be conservative. In addition, some combinations were dropped so the allowable weak axis bending for the corresponding stress classes had changed slightly.
Note that the uniform beam materials are typically only in those beams that have both positive and negative moment stress. The balanced column database is used only in those column applications that are subject to significant lateral loading but no axial tension.
No.3 grade lumber is now available for all soft lumber species. Previously it was available only for Southern Pine.
For version 8.1, construction loads (duration factor 1.25) were removed as a load type from the program and replaced with roof Live loads (duration factor 1.0), to comply with ASCE 7-05 2.4.1 and IBC 2009 1605.5.3.1 definition of load types and combinations. To allow for construction loads, a checkbox was added to indicate all live loads are construction loads.
This change made it impossible to model construction loads and occupancy live loads simultaneously, which was possible with previous versions of the program. However NDS 2005 Commentary C2.3.2 indicates that it is conventional practice to consider a roof live load as a construction load for which the 1.25 load duration factor applies, so it is in fact necessary to allow both construction roof live loads and occupancy live loads on the structure at the same time.
To rectify this, Sizer now has a check box "All roof live loads are construction loads" which allows roof live loads to be treated as construction loads even when live loads on other parts of the structure are not.
The program was using the "b" face for the minimum bearing length calculation for a 90-degree oblique angle (plank design) when the d face is actually the bearing face. This has been corrected.
The program continues to use the "b" face for the minimum bearing length calculation oblique members rotated other than 90º, as the program does not input the actual bearing width in this case. You must adjust the resulting bearing length for the actual bearing width compared to b.
For glulam and SCL materials, the software did not implement NDS 3.3.3.1, which sets the lateral stability factor CL to 1 .0 when the member width is greater than the depth. Instead, the program calculated the factor according to the rest of 3.3.3, occasionally creating a factor slightly less than 1, resulting in a slightly conservative allowable bending capacity.
As design proceeded from left to right for the supports on a beam, the calculation of compressive resistance at an angle to the grain F’θ using NDS 3.10.3 mistakenly tended closer and closer to the value of F’c┴, the resistance perpendicular to the grain. This resulted in incorrect minimum bearing length values for intermediate and right supports for sloped members.
The note that appears under the Modification Factors table for notched glulam beams in the Design Results now indicates that it is from the Expanded version of the NDS Supplement 5A table, and indicates more clearly that this factor is multiplied by the Cn factor from NDS 3.4.3.
Starting with version 6.4, released in July, 2006, the reactions due to dead line loads on sloped members are lower than they should be. The discrepancy is small ( less than 1%) or angles 20 degrees and less, less than 5% for angles less than 30 degrees and less than 10% for angles less than 40%. However for larger angles, the shortfall increases such that for 60 degrees the reported reactions are only 63% of the expected reactions and for 80 degrees only 20% Note that dead load reactions for the same UDL on sloped members increases with the slope angle because the dead load is measured per unit foot along the slope.
These incorrect reactions appear in the reaction diagram and in the reactions table of the design check report. They result in inadequate minimum bearing length design, and incorrect reactions transferred into supporting members in Concept Mode.
The shortcut key combination of Ctrl+V displayed in the menu, did not open the Sizer Settings menu / Change. The display has been changed to Ctrl+Q, which is the correct shortcut for the settings menu.
The repetitive member checkbox status was not refreshed when reopening an existing wall stud project.
The program now shows the most recent design codes implemented in the Help About box, under the version number.
This topic added to the help notes and referred to in several other places, stating:
NDS Glulam Tables 5A to 5D are not consistent with Appendix D with respect to the calculation procedure for E'min, the modulus of elasticity used for the beam stability factor CL. The NDS Tables use the equation in D-4 in NDS appendix D with a value of 1.03 to convert E' to E'min, that is, they do not use the 1.05 value for glulam specified there. The program uses the correct 1.05 value, creating a small discrepancy between the lateral stability calculated using the published table values and the Sizer software.
Two topics have been added to the help file to better explain assumptions regarding loads analysis on sloped members.
This topic explains the adjustments made in the analysis engine to the due to the assumption that wind loads are considered to be directed normal to the member, and all other loads vertical, and due to the fact that dead line loads are considered to be distributed along the slope wheras all other load types are distributed along the projection
This topic explains the further adjustments made to re-adjust the reactions that result from these loading assumptions so that they are oriented in a vertical direction and capture the entire vertical component of the applied loads.
Some outdated information regarding the unsupported and effective lengths Lu and Le for glulam lateral stability factor CL calculations was corrected.