Code of Massachusetts Regulations
780 CMR - STATE BOARD OF BUILDING REGULATIONS AND STANDARDS
Chapter 16 - Structural Design
Section 1609 - WIND LOADS
Subsection 1609.3 - Basic wind speed
Current through Register 1531, September 27, 2024
The basic wind speed, in mph, for the determination of the wind loads shall be determined by Figure 1609. Basic wind speed for the special wind regions indicated, near mountainous terrain and near gorges shall be in accordance with local jurisdiction requirements. Basic wind speeds determined by the local jurisdiction shall be in accordance with Section 6.5.4 of ASCE 7.
In nonhurricane-prone regions, when the basic wind speed is estimated from regional climatic data, the basic wind speed shall be not less than the wind speed associated with an annual probability of 0.02 (50-year mean recurrence interval), and the estimate shall be adjusted for equivalence to a 3-second gust wind speed at 33 feet (10 m) above ground in Exposure Category C. The data analysis shall be performed in accordance with Section 6.5.4.2 of ASCE 7.
1609.3.1 Wind speed conversion. When required, the 3-second gust basic wind speeds of Figure 1609 shall be converted to fastest-mile wind speeds, Vfm, using Table 1609.3.1 or Equation 16-32.
Click to view image | (Equation 16-32) |
where:
V3S = 3-second gust basic wind speed from Figure 1609.
TABLE 1609.3.1 EQUIVALENT BASIC WIND SPEEDSa, b, c
V3S | 85 | 90 | 100 | 105 | 110 | 120 | 125 | 130 | 140 | 145 | 150 | 160 | 170 |
Vfm | 71 | 76 | 85 | 90 | 95 | 104 | 109 | 114 | 123 | 128 | 133 | 142 | 152 |
For SI: 1 mile per hour = 0.447 m/s. a. Linear interpolation is permitted. b. V3S is the 3-second gust wind speed (mph). c. Vfm is the fastest mile wind speed (mph). |