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Here is a web enabled Asce7-10 wind load program. The program displays the Wall Components and Cladding design pressures for the selected conditions. I use these programs to verify the design pressures provided by the architects or to create them for estimating or engineering purposes. It is highly recommended you review the building code to understand where the information comes from. Refer to the links page for various building code web sites. As you will see in the Asce7-10 Building Code there are four parts for determining the components and cladding. This program utilizes Part 1: Low-Rise Buildings h<= 60 and Part 3: Buildings with h>60 ft to calculate the design pressures. The program will automatically determine the use of Part 1 or Part 3. There are many references on the web about the big changes to the ASCE7-10 code. A few of the key changes are: The Importance factor used in the older code is no longer utilized and is now part of the wind speed maps. The Wind speed maps are separated into category 1 through 4. Refer to your local jurisdictions to determine which map and wind speed to use. For me the biggest change utilizes the LRFD (Load Resistance Factor Design) and ASD (Allowable Stress Design). In general the LRFD will be used for the main structure and the ASD will be used on the components and cladding. In these calculations the ASD velocity pressure is reduced by 60%. To get started select and enter your project information. A note about the Kzt factor: Kzt is a topographic effect factor to account for speed up over hills. Refer to your states Kzt values and adjust the value as required. Since I reside in Florida I use Kzt equals one and established that as the default value. I found a paper from the Florida International University stating “few places in the state of Florida would warrant an escarpment factor greater than 1.0, therefore Kzt is unnecessary in the current endeavor.” I also found a web site showing the Kzt factors for Seattle, Washington from the Department of Planning and Development, their values range from 1.12 to 2. Refer to the links page for information. A note about the Kd factor: Kd is a directionality factor. Over the years the Kd factor value has stirred up some controversy as to whether the value is 0.85 or should be one. I have set the default value to 0.85; if you are uncertain what value to use change the value to one for a worst case scenario. I found a reference to this question at Engineering Express to support the Kd factor equals 0.85. Refer to the links page for information. A note about the Design Load Method: The new ASCE7-10 code utilizes the Strength Design Load also called (LRFD Load Resistance Design Load) method and the Allowable Stress Design Load (ASD) method. The Florida Building Code 2010 (FBC2010) utilizes an Ultimate Design Wind Speed Vult and Normal Design Wind Speed Vasd in lieu of LRFD and ASD. The FBC2010 uses a wind speed conversion where the Vasd is reduced by 60 percent; this happens by multiplying the Vult by (0.6). Since the velocity pressure is reduced by 0.6 in the formula for ASCE7-10 and is reduced by 0.6 in the wind speed which is used in the velocity pressure formula for FBC2010 this makes the design pressures for both methods the same. Please take a look at MetalOpt material optimizer and don't forget to book mark this page for quick access. Thank you for looking.
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