Wind Load Generation Bugs

Wind Load Generation On Vertically Discontinuous Walls (Bug 1797)

The wind loads generated on an upper level wall that is not the same extent as the lower wall, use the extent of the lower wall for the loads on the bottom half of the upper level wall. Therefore, many configurations received more or less loading than they should, for example:

• A wall that is common to two blocks in plan, but exists on an upper level on only one of the blocks.
• Overhangs or cantilevers

  Load Generation after Block Size Change (Bug 1768)

The ridge elevation was not being properly updated upon change in block size, resulting in inaccuracies in many aspects of load generation in this case, including:

• the tributary width of wind loads
• calculations using mean roof height or ridge height

This problem would be corrected if you modified the roof via the roof input dialog after changing block size. As most users modify the blocks, then proceed to define the roof, it rarely occurs in normal practice.

Exposure Factor for Imperial Units (Bug 1670 )

When imperial units were selected, the exposure Factor Ce reported in the Design Results and used for wind load generation was always 1.72, but it should be related to building height by NBC 1995 Table 4.1.8.1. As a consequence, wind loads are increased by between 40% and 90%. When metric units were selected, the exposure factor was correct.

Zero-overhang roof wind loads (Bug 1697)

When generating loads on the side panels of gable end roofs with no overhang, extra tiny loads were sometimes showing up at the edges of the roof in Plan View. They no longer appear.

Low-rise Note 8 Loads on Hip Ends (Bug 1623)

For hip roofs, the loads on the upper portion of the hip ends generated according to the Low-rise Method in NBC Commentary B7 Note 9 (now I7 Note 8) led to positive wind loads despite the fact that they have negative coefficients. This has been corrected

End zones (Version 2002a)

Problems with definition of end zone on convoluted structures were fixed in Version 2002a.

Wind loads on trapezoidal roof panels (Version 2002a)

Problems that occasionally occurred with wind loads on trapezoidal roof panels were fixed in Version 2002a.

Flat Roof Load Generation (Bug CSW7-12)

The program was creating both Case A and Case B loads for only one direction on the structure in the case of a flat roof, leading to unequal loading for square structures. The program now considers only the loads in the direction of the force for flat roofs, which have the same coefficients for Case A and Case B.

Generation after Wall Move via Keyboard Input (Bug CSW7-13)

When loads are generated after walls are moved by changing their co-ordinates in the wall input form, wind loads were not generated on some of the moved portions of the walls. This affected structures such as L-shaped, U-shaped, and those with vertical irregularities and has been corrected.