In terms of determining the risk category to a building component mounted to a building, the component ‘inherits’ the design properties of the structure. So a sign attached to a risk category II structure would be risk category II. If the sign is freestanding and not part of a main structure, while matching the…
Many who don’t understand how wind works will state a product is rated to a specific wind velocity which is false advertising and not true. “Rated to 180 MPH wind” is frequently seen in marketing materials which is a false and misleading statement that comes with many unwritten disclaimers. The formula that converts wind velocity to…
Per the Aluminum Design Manual (ADM) 2010, the allowable bending stress of round tubes shall be determined for the limit states of yielding, rupture, and local buckling: that given by section F.6.1 (compressive yielding), or that given by section F.6.1 (tensile yielding), or that given by section F.6.1 (tensile rupture), or that given by section…
Note: Updated March 2018 in response to 3 negative user feedback comments for more information. Please thumb this up! A canopy is a structure which provides overhead protection from the elements such as rain, snow, or sunlight. Canopies can be attached to a structure or they can be free standing with their own supports. They…
A building is considered “enclosed” if it does not comply with the requirements for open or partially enclosed buildings (ASCE 7-10, Section 26.2, “BUILDING, ENCLOSED”). From the ASCE 7-05 Commentary BUILDING, ENCLOSED, OPEN, PARTIALLY ENCLOSED: These definitions relate to the proper selection of internal pressure coefficients, GCpi . Building, open and building, partially enclosed are specifically…
A building is considered open if each wall is at least 80 percent open (ASCE 7-10, Section 26.2, “BUILDING, OPEN”). This condition is expressed for each wall by the equation Ao ≥ 0.8 Ag where Ao = total area of openings in a wall that receives positive external pressure, in ft2 (m2) Ag = the…
A building is considered “Partially Enclosed” if it complies with both of the following conditions (ASCE 7-10, Section 26.2, “BUILDING, PARTIALLY ENCLOSED”): the total area of openings in a wall that receives positive external pressure exceeds the sum of the areas of openings in the balance of the building envelope (walls and roof) by more…
The Building Codes in the US reference ASCE-7 for the design of the components and cladding of buildings (26.1.2.2 ASCE 7-(10)). The theory of wind design goes that the smaller the area in consideration, the greater the probability that a maximum burst of wind will occur in that area over any 3 second period. Wind…
From the 5th Edition of the Florida Building Code (2014) section 1603.1.4 and from section 1603.1.4. of the 2012 International Building Code, construction documents shall show the following: Ultimate design wind speed, Vult (3-second gust), miles per hour and nominal design wind speed (Vasd) as determined in accordance with code section 1609.3.1 Risk Category…
Missile Level E 6.2.1.1 Enhanced Protection (Essential Facilities): Buildings and other structures designated as essential facilities, including but not limited to hospitals, other health care facilities having emergency treatment facilities, jails and detention facilities, fire, rescue and police stations, and emergency vehicle garages, designated emergency shelters, communications centers and other facilities required for emergency response,…
First, it needs to be said that there is a complicated formula that converts wind velocity to wind pressure. Many wind pressure values can exist from a single wind velocity which vary based on roof height, topography, terrain, even code version, and more. See our wind speed to wind pressure calculators for different ASCE codes by…
The one-third stress increase has a long history of use in Allowable Stress Design (ASD). It is most commonly used to account for the improbability of two transient loads concurrently acting at their maximum lifetime values– for example, will the design earthquake really occur at the same time as the design snowstorm? Recent changes in…
About Exposure D Exposure ‘D’ is a multiplier when converting wind velocity to wind pressure that represents coastal areas. It’s used in many formulas in ASCE 7 for wind, a larger topic than covered here. Non coastal areas have Exposure categories B and C. Exposure D is a moving target from the coastline based on…
The answer to that question varies with location and type of building, but feel free to download the attachment listed below which is an exhaustive list of the wind speeds used in the general Florida locale and another general map for the country. Please be sure to verify with your local Building Department as these…
YES. The loading requirement of “Rooftop Structures” has been revised in ASCE 7-10. Essentially, buildings less than 60-ft still have the requirement that their wind load be multiplied by a GCr factor applied to the wind pressure that can be as high as 1.9. This has been in place since the 2007 version of the…
Most all products are evaluated using the ASD method (unless noted otherwise). ASD method in, then ASD method out. Among the notable changes in ASCE 7-10, the wind speed map and the importance factor for wind loads have been replaced with three wind load maps based on difference and newly defined return periods and for…