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#1 Top Question Asked
What are the updates with the ASCE 7-10 programs?
ASCE 7-10 Wind Speed Map Updates
· The wind speed map for all locations has been revised & Importance Factors have been removed.
· There are 3 new wind speed maps. Wind speed maps are provided for each Risk Category as opposed to a single map with importance factors (300 year period, 700 year return period, 1700 year return period). The difference is that all of the previous ASCE 7 Standards had referenced only one wind velocity map for all Risk Categories.
· New wind speed maps have replaced the existing maps that are directly applicable for determining design wind pressures using the strength design approach. Different maps are provided for different Risk Categories instead of a single map with importance factors to be applied for each Risk Category.
· Wind speed values are now represented in the ASCE 7-10 as "Ultimate" wind speeds.
· Strength design level wind speeds replace the ASD level wind speeds.
· Comparative hurricane wind speeds are lower than those given in the ASCE 7-05.
· The wind speeds in the maps are much higher than those in previous editions, the Load Factor on "W" in Section 2.3.2 is now 1.0 instead of 1.6 as established in the ASCE 7-05.
· Importance Factors have been used in previous editions of the ASCE 7 to adjust the velocity pressure to different annual probabilities of being exceeded. However, the use of Importance Factors was an approximate means for adjusting the return period because the slope of the wind speed vs. return period curves differ. The distance inland where the hurricanes can influence wind speeds increases with the return period. This situation was not adequately addressed by using Importance Factors from a table.
Updates for allowable Wind Speeds That Supersede Wind Speeds Provided In The ASCE 7-10
· The basic wind speed shall be increased where records or experience indicate that the wind speeds are higher than those reflected in Fig. 26.5-1 of the ASCE 7-10.
· Mountainous terrain, gorges, and special wind regions shown in Fig. 26.5-1 of the ASCE 7-10 shall be examined for unusual wind conditions. The authority having jurisdiction shall, if necessary, adjust the values given in Fig. 26.5-1 to account for higher local wind speeds. Such adjustment shall be based on meteorological information and an estimate of the basic wind speed obtained in accordance with the provisions of ASCE 7-10 Section 26.5.3.
· For areas outside hurricane-prone regions, regional climate data shall only be used in lieu of the basic wind speeds provided in the ASCE 7-10 Fig. 26.5- when (1) approved extreme-value statistical-alaysis procedures have been employed in reducing the data; and (2) the length of record, sampling error, averaging time, anemometer height, data quality, and terrain exposure of the anemometer have been taken into account. Reduction in basic wind speed below that of Fig. 26.5-1 shall be permitted.
· In hurricane-prone regions, wind speeds derived from simulation techniques shall only be used in lieu of the basic wind speeds given in the ASCE 7-10 Fig. 26.5-1 when approved simulation and extreme value statistical analysis procedures are used. The use of regional wind speed data obtained from anemometers is not permitted to define the hurricane wind-speed risk along the Gulf and Atlantic coasts, the Caribbean, or Hawaii.
· In areas outside hurricane-prone regions, when the basic wind speed is estimated from regional climatic data, the basic wind speed shall not be less than the wind speed associated with the specified mean recurrence interval, and the estimate shall be adjusted for equivalence to a 3-second gust of wind speed at 33 ft (10 m) above the ground in Exposure C.
ASCE 7-10 Importance Factor Update
· In the equation for Velocity pressure (qz) the importance factor has been removed, and the coefficient 0.00256 (0.613 in SI) shall be used except where sufficient climatic data are available to justify the selection of a different value of this coefficient/factor for a design application.
ASCE 7-10 Category “D” Update
· Surface Roughness Category "D" now applies to all water surfaces including water surfaces in hurricane prone regions.
ASCE 7-10 Updates for the State of Hawaii
· Entire State of Hawaii has its own special wind region.
· The reasoning behind this is due to the highly complex three-dimensional topography in the State of Hawaii. This conclusion was reached by numerous studies. The topography has speed-up effects that cannot be adequately portrayed by a single statewide value of wind speed nor at the macro-scale of a national map. The State of Hawaii has addressed this issue with the development of wind maps for each local jurisdiction.
· For these new "special region maps" for the State of Hawaii, you must reference the Hawaii State Building Code.
· Although the probabilistic reference wind speeds are provided for Hawaii in the ASCE 7-10, the intent is that the actual design wind speeds are to be further modified as determined from the authority having jurisdiction. Wind speeds are identified simply to provide the reference wind speed for each Risk Category, and also ensure that the wind-borne debris region criteria in the ASCE 7-10 is appropriately triggered by the net value of net effect wind value.
Reference: General Requirements for Determining Wind Loads & ASCE 7-10
#2 Top Question Asked
What is the difference between Ultimate Design Wind Speed and Nominal Design Wind Speed?
Nominal Design Wind Speed is a reduction of the “Ultimate Design Wind Speed” by 40%. This is a 40% reduction of the Ultimate Design Wind Speed positive and negative pressures. Or you could also get the 40% reduction by entering in the Nominal Velocity and plug it into your wind load calculation formula. The way you calculate the Nominal Velocity is to multiply the Ultimate Velocity (found on the Velocity Maps provided by ASCE 7-10) by the square root of the value 0.6.
As far as when to know if the Nominal Design Wind Speed is accepted, you will need to contact your county’s permit department to make sure your structure can pass with a Nominal Design.
On our program, you can toggle between the Nominal and Ultimate Wind Speed Designs. You are required to enter in the Ultimate Velocity provided on the ASCE 7-10 Velocity Maps, and our wind load programs will automatically calculate the Nominal Velocity and the Nominal Design Pressures for you.
#3 Top Question Asked
What is the difference between the Standard Edition and the Building Permit Edition for both ASCE 7-02 & 7-05 programs?
The Standard Edition strictly calculates the wind load pressures according to the Building Information that is entered in. The Building Permit Edition (BPE) has additional information that is required by your building permit department. Diagrams and the required information have been added. There are separate sheets that are automatically created based on the input. For example, if you have a Gable Roof, then you would select the Gable Roof tabbed sheet and the information and diagrams are automatically created. All you have to do is hit ‘print’ and you have all your wind load information to submit to your Building Permit Department. The same is true for all other roof types, windows, and doors. This makes the wind load permit process easy for you and your permit department. Winloadcalc.com has created the BPE to make the rigorous wind load process a breeze.
#4 Top Question Asked
What is the difference between the ASCE 7-98 and the Latest ASCE 7-02 & 7-05?
First off, your building permit department will deny your information if it does not abide by the latest ASCE 7. Versions of ASCE 7-98 and lower are obsolete. They should not even be practiced. There have been major changes. Below are some major changes that would affect your design according to C&C.
- Method 1 has been modified. Roof slope calculations have been modified.
- Exposure A is no longer used.
- Parapet calculations were added.
- Permission to interpolate the exposure category for the surface roughness length parameter, using an acceptable/reasonable procedure.
#5 Top Question Asked
What is the difference between the Zones for the Walls and Roof? (You can also see examples on our Instructions page (Link to Instructions page).
The “Zones” are the locations on the walls and roof of a structure that identify the locations that have more pressure applied to them than other locations. The Zones that have see the most pressure are the corner Zones of the walls (Zone 5), and the perimeter Zones of the roof (Zones 2 & 3). The interior Zone pressures do not have as much pressure applied to them as the corner and perimeter Zones. The interior Zone of the wall is Zone 4, and for the roof is Zone 1.
The value of “a” (which is automatically calculated for you in our program) will be your starting point. This value (a) is the horizontal dimension that provides you with Zone 5 for your walls and Zone 3 for (the corner of) your roof. You measure from the corner, inwards. For your walls, Zone 4 will be the remaining area between the Zones 5’s measured from each corner, and for your roofs, Zone 2 will be the remaining area between the Zone 3’s measured from each corner. Also, for roofs, Zone 1 is the entire area left over from Zones 2 & 3. Additionally for the roofs, you can divide up the areas for the Zones (1,2, & 3) to be the areas measured between your rafters; since this is the area between the tie-downs.
Below is a diagram that should help you visualize how to break up the zones.
1. Zones 1, 2, & 3 are always applied to the roof.
a. Zone 3: are the edge or corner sections; always equal to the value of “a”.
b. Zone 2: are the perimeter sections; minus the Zone 3 (edge/corner) areas.
c. Zone 1: are the interior sections. Basically the interior area left over after
subtracting the areas of the Zone 3, and Zone 2.
2. Zones 4 & 5 are always applied to the walls.
a. Zone 5: are the corner sections; always equal to the value of “a”.
b. Zone 4: are the interior sections; or the area remaining after subtracting the
Zone 5 sections.
3. Remember: The Value of “a” is always applied to the roof and wall corners.
4. Remember: Any door or window dimension that falls within the area of “a”
(edge/corner = Zone 5) section must have the Zone 5 applied to it.
5. Remember: Any opening dimension that falls with the area of “a” (edge/corner =
Zone 3) on the roof (such as a sky-light) must have the Zone 3 applied to it.
#6 Top Question Asked
Can you get refunded for the purchase of programs?
We have a disclaimer that states the following below, and is also provided with your program:
By using the Windloadcalc.com program it is agreed that the user takes all responsibility for
directors, officers, agents, and shareholders of the Windloadcalc.com are not held
responsible, or accountable for design pressures and all calculated data taken from the
This program is not intended to replace the services of a professional engineer. This
program is simply a tool to help process needed information quickly and accurately under
the ASCE 7-10Standard (ASCE 7), and the International Building Code (IBC). It is always
good practice to consult a professional engineer in using this product.
This program is not responsible for information not included in the ASCE 7 Standards, or
With the purchase of this program you have agreed to the use of this program for the use at
one operating station/computer. Multiple use of an individual program is prohibited.
All sales are final at the time of purchase.
With the purchase of this program, you have agreed to follow the information written above.
This serves as a legal document.
Other Frequently Asked Questions about the Wind Provisions of ASCE 7
1. Why have the Velocity Maps changed in various ASCE Standards?
You may be wondering why the maps have changed from the previous wind velocity maps. Well, since the development of the model used for the ASCE 7-98 wind speed map, significantly more hurricane data has become available which improves the modeling process. The new hurricane hazard model indicates that the hurricane wind speeds given in ASCE 7-05, 7-02, and 7-98 are conservative. This conservatism is evident even though the overall rate of intense storms produced by the new model is higher compared to the rate of intense storms produced by the model used to develop the wind speed maps in ASCE 7-98 through ASCE 7-05.
2. Is it possible to obtain larger scale maps of basic wind speeds (see Figures 26-5.1A-C) so that the locations of the wind speed contours can be determined with greater accuracy?
9. Under what conditions is it necessary to consider speed-up due to topographic effects when calculating wind loads?
16. Section 26.2 of the Standard provides definitions of glazing, impact resistant; impact-resistant covering; and wind-borne debris regions. To be impact resistant, the Standard specifies that the glazing of the building envelope must be shown by an approved test method to withstand the impact of wind-borne missiles likely to be generated during design winds. Where does one find information on appropriate test methods?
Some of the FAQ questions above are reprinted from "Guide to the Use of the Wind Load Provisions of ASCE 7-02"
Q) Is there a typo in the new ASCE 7-05 Standards on Figure 6-21 for the ‘Round ([D * sqrt of qz] > 2.5). In the '"Very Rough" row and the "25 – h/D column"?
A: Yes. Instead of 0.2, it should be 1.2
Q) Why do I have to enter a frequency and damping ratio for both the sign and the supports?
Q/A) If you have all the “Sign Information” filled in to the best of your knowledge, but your force output is zero……Verify your “Open Area of Sign” for the value of sigma is most likely not between 0.1 & 0.7.
Q/A) Value of “Kd” is only used in conjunction with load combinations specified in ASCE 7-02, Section 2, 2.3 & 2.4. So, if your calculation consists of a combination of loads, say for ice, flood loads, select “Yes” from the pull-down list for “Kd.”
Q) Can the Signs Program be used for Solid Free Standing Wall & Lattice Framework calculations?
Q) Is the equation for Rl = Rb correct?
Q) Why does my “Effective Area” value equal something other than what I inputted?
A) The program calculates the necessary adjustments, according to the ASCE 7-02 handbook. This typically results in cathedral type windows; very tall and narrow.
Helpful Information for Windload Design Program
Program works in Windows Excel only.
· Opening information for maximum and minimum pressures are given for all openings with any given Building Information.
· Components & Cladding Wind Loads are given per code requirements for all heights above and below 60 feet.
· You can adjust the program to fit your computer screen by adjusting the percentage on your ‘STANDARD’ toolbox. Or go to the ‘VIEW’ pull down menu. Go to ‘TOOLBARS.’ Select ‘STANDARD.’ Now you can adjust your screen size percentage.
· If you notice that your value(s) in the cell(s) for ‘Total Area’ do not coincide with your values in the width & height columns, it is because the values have been adjusted for the most appropriate value for that given area. According to Florida Building Code, 2001 catalog in Section 1606.1.5 under Effective Wind Area; page 16.6.
· When needed, information is interpolated to give the most precise value.
EXCEL imported into AUTOCAD
Follow these steps to insert an Excel spreadsheet into AutoCAD.
When you are finished with your Excel spreadsheet:
a. Go to FILE
b. Select Print Area
c. Select Set Print Area (Select what you want to show up in AutoCAD)
d. Select Edit
e. Select Copy
2. Leave Excel spreadsheet open. (If you save after you do the Copy command,
Go back to Edit and select Copy. In other words, Copy should be the last thing done.)
Go to AutoCAD 2000, 2002, 2004, 2005, 2006
a. Select Edit
b. Select Special Paste (after this, a window pops up on your screen)
c. Select Paste Link
d. Select OK
Right-click on the spreadsheet just inserted
a. Select Properties (here you can scale your inserted Excel spreadsheet)
i. Just a hint. Typing in the value 0.2 works well when scaling down, under the text size area. (i.e.: Arial 18 or 10 = 0.2)
From this point on, any changes made in the excel spreadsheet will be updated automatically in AutoCAD.
However: If you make changes outside of the selected Print Area, those changes will not appear in AutoCAD. Meaning, if you added onto a schedule be sure that it is within the selected Print Area. If not, you will have to go through the procedure again.
Windloads are for wind load calculations, wind load criteria, and wind load structures. Wind loads or windloads are required by law for a building permits in Florida, California, Louisiana, & other states are starting to require wind loads as well. The windloads (wind loads) required are referenced from the ASCE 7-02, ASCE 7-05, and ASCE 7-10. ASCE uses criteria for windloads (wind loads) to calculate the proper wind load requirements needed for ASCE 7 wind load design. The Windloadcalc.com wind load program serves as a wind load calculator and provides wind load analysis of all types of structurs. A wind load map is provided with the purchase of any wind load program, and there are instructions within the program that help the user understand how to calculate wind loads. Enjoy our wind load software.
all the designs and calculated solutions transferred and taken from the program. The
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