CHECKWIND v3.1.0 is now live and can be downloaded here. New features and enhancements include:
- AS/NZS 1170: Topographic feature midpoints (Lu) are now determined using interpolation, leading to more accurate site Topographic Multipliers (Mt).
- ASCE 7-10/ASCE 7-16/TIA-222-G/TIA-222-H: Topographic feature midpoints (Lh) are now determined using interpolation, leading to more accurate site Topographic Factors (Kzt).
- Define water level for topography detection near inland lakes and rivers with surface levels above mean sea level.
CHECKWIND v3.0.0 is now live and can be downloaded here. New features and enhancements include:
- Now optimised as a 64-bit application (no more pesky System.OutOfMemoryException errors).
- New automated Topographic Multiplier (Mt) detection algorithm to AS/NZS 1170 (more on that below).
- Users can now override Topographic Multiplier (Mt) values.
- Introduction of our own Basic Wind Speed maps to ASCE 7-10, ASCE 7-16, TIA-222-G and TIA-222-H.
- Improvements to automated Exposure Category (Kz) detection to ASCE 7-10, ASCE 7-16, TIA-222-G and TIA-222-H.
- New automated Topographic Factor (Kzt) detection algorithm to ASCE 7-10, ASCE 7-16, TIA-222-G and TIA-222-H based on Crown Castle and SEAW RSM-03 guidelines.
Topographic Multiplier (Mt) Detection Improvements
Until now, CHECKWIND has used a combination of the 500 m segment criteria from the AS/NZS 1170.2 commentary (though with a “rolling” 500 m segment instead of less accurate 500 m increments from the crest suggested by AS/NZS 1170.2), in addition to our own local minimum criteria to determine the base of a feature.
Figure 1: AS/NZS 1170.2 C4.4.2
However, the problem with utilising the local minimum criteria is that the base might be determined as being at the bottom of a valley with a steep slope for certain terrain, leading to overly conservative Mt values, as shown in Figure 2.
Figure 2: CHECKWIND v2.2.1 results
The local minimum criteria was intended to avoid situations where the 500 m segment might identify the “base” as being halfway up/down a slope, which seemed counter intuitive. Regardless, we’ve adjusted the algorithm and removed the local minimum criteria and now rely solely on the 500 m segment method. This has led to an overall reduction in Mt values across all of our test sites, as shown in Figure 3.
Figure 3: CHECKWIND v3.0.0 results