Background Building codes require that buildings be classified by their level of importance in determining the risk taken with safety factors against their failure under critical design loads. Calculations for the structure’s overall stability, flexure, and fatigue are all based on the assumption of a given risk category design level. ASCE 7 references risk category…
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…
FLOOD GLOSSARY The following is provided as a curated summary of terms taken from the referenced standards that appear in the article footing. NATIONAL FLOOD INSURANCE PROGRAM (NFIP) The Federal program, create by an act of Congress in 1968, that makes flood insurance available in communities that enact satisfactory floodplain management regulations. FLOOD INSURANCE…
An engineer’s walk through of the design requirements for flood resistant design of building components With Engineering Express’s early start with floodproofing designs for floor barriers and exterior glazing in projects across the US, we quickly became experts in this field. We’ve witnessed and directed static and dynamic flood testing, sat on industry meetings, met…
INTRODUCTION The main purpose foundations serve is to distribute and resist the forces or loads experienced by the host structure due to wind, rain, snow, seismic, & other load conditions. When it comes to building components such as generators, signs, and fences the code leaves a gray area for foundation design. This happens because most…
The Applied Technology Council (ATC) offers site-specific information that is used in our calculators to determine the wind velocity. For the best results, the address of the site may be used. To find your wind speed, follow the step-by-step guide below. Navigate to https://hazards.atcouncil.org/#/ Enter your address, zip code, or city and state in the search…
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…
ASCE 7 separates wind loading into three types: Main Wind Force Resisting System (MWFRS), Components and Cladding (C&C), and Other Structures and Building Appurtenances. MWFRS is defined as “(a)n assemblage of structural elements to provide support and stability for the overall structure.” Typically, members which receive loading from two surfaces are designed to resist MWFRS…
If you’d prefer to hear this in Spanish, use the video below. Si prefiere escuchar esto en español, utilice el siguiente vídeo.
The directionality factor (Kd) used in the ASCE 7 wind load provisions for components and cladding is a load reduction factor intended to take into account the less than 100% probability that the design event wind direction aligns with the worst case building aerodynamics. Per ASCE 7-10,Section 26.6, the Directionality Factor Kd is defined…
Per ASCE 7-10, buildings are composed of 5 different zones, depending on the wind loading they are subjected to. These zones are defined as follows: Zone 1: Has the lowest load; this zone accounts for approximately 80% of the roof surface, represented in the interior zones of the roof. Zone 2: Higher loading than Zone 1; this…
Per ASCE 7, the Mean Roof Height (h) is defined as the average of the roof eave height and the height to the highest point on the roof surface, except that, for roof angles of less than or equal to 10°, the mean roof height is permitted to be taken as the roof eave height. Visually, AAMA TIR A15-14…
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…
In the 5th Edition Florida Building Code (2014), missile level E is valid in and outside of the HVHZ (Broward and Dade Counties) when it came to essential facilities. Sure it is in section 1626.2.4 of the FBC which falls under HVHZ but section 449.4.2.5.1 refers to 1626. In previous codes it was in section 419…
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…