Frequently Asked Questions

Note:- Any information in this page relating to interpretation of building codes and standards is offered as a guide subject to verification by the user. Readers may freely ask further questions or offer comments via e-mail.

What types of payment do you accept?
Do you use secure server software to process online orders?
How do I know which version of Microsoft Excel is installed in my computer?
How do I install a Modstruct module on my computer?
How do I uninstall a Modstruct module?
How do I run a Modstruct module?
Do I need to know how to use Excel?
How can I tell what an identifier or variable represents?
Why are the result cells filled with ####, #N/A, #DIV/0! or blank?
Once I have saved and closed a project file, can I return later to change the  project name or designer?
Why is the Print button in my Excel File Menu disabled when a Modstruct module
    is running?
How do I obtain a printout of the entry data, calculations and results?
Why is the first page of the printout (and each of the other pages, if any) being printed on more than one sheet?
How do I obtain a printout of the Diagram, ReadMe or Notation sheet?
Having acquired the latest edition of a program, why would I want a downgrade?
How can these programs be be used as learning tools?
Sundry questions on Metal Deck Diaphragm
Sundry questions on Wind Forces at Base of Enclosed and Partially Enclosed Rigid
    Buildings of All Heights
Sundry questions on Wind Pressures on Components and Cladding of Enclosed and
    Partially Enclosed Buildings up to 60 ft.

0001: What types of payment do you accept?
We accept VISA and MasterCard. You can safely enter your credit card number via our secure server which encrypts all submitted information. We also accept checks or money orders denominated in U.S. dollars. Simply complete and print the off-line order form, and mail it with your check or money order to the address below. We will process your order immediately upon receipt. Please note, however, that orders paid by check will not be shipped until the funds are cleared.
                               Modular Structural Engineering Software, Inc.
                               2810 NW 51st Ter.
                               Margate, FL 33063-1623

0002: Do you use secure server software to process online orders?
Yes! Our secure server software (SSL - Secure Socket Layer) is the industry standard and among the best software available today for secure commerce transactions. It encrypts all of your personal information including credit card number, name and address, so that it cannot be read as the information travels over the internet.

0021:How do I know which version of Microsoft Excel is installed in my computer?
Click Start -> Programs -> Microsoft Excel -> Help -> About Microsoft Excel
Read the version number at the top of the panel.
If the version number is less than 7.0 you cannot run the Modstruct modules.

0031: How do I install a Modstruct module on my computer?
To install the first or any subsequent module :-
Close all applications running on your system.
Insert the installation disk in your CD/DVD drive.
After a short wait the installation will start automatically on autorun.
If the installation does not start, click Start -> Run -> d:setup.exe -> OK
    where d: (or e: or whatever) represents the drive letter of your CD/DVD drive.
Follow the setup instructions that appear on the screen.

0035: How do I uninstall a Modstruct module?
Click Start -> Settings -> Control Panel -> Add/Remove Programs.
Select the module to be uninstalled.
Follow the onscreen instructions.
If all modules are uninstalled, the remaining empty folder may be deleted manually.

0040: How do I run a Modstruct module?
Presumably, Microsoft Excel is already installed on your computer.
Click Start -> Programs -> Modstruct.
Select and click on the module you wish to run.
If a dialog box about the presence of macros appear, click Enable Macros.
Enter a filename (we suggest an abbreviation of your project name coupled with your calculation sheet number, e.g. MyProj-16).
Press the Tab key to take you to the next data entry cell.

0041: Do I need to know how to use Excel?
No, but if you wish to review the formulas in depth it helps to be familiar with conditional statements, maximum and minimum values, arrays and look-up tables.

0042: How can I tell what an identifier or variable represents?
Each identifier is either labeled, self-explanatory by column headings or defined in a comment indicated by a red triangular flag in the upper right corner of the cell containing the identifier. A comment is accessed by hovering the mouse pointer over the red flag. In addition, all identifiers are defined in the Notation sheet which is accessed by clicking the Notation button at the bottom of the screen.

0043: Why are the result cells filled with ####, #N/A, #DIV/0! or blank?
All of the data entry cells adjacent to or under the blue labels may not have been filled by the user or some may have been filled with irrelevant or out-of-range data. Consult the referenced standards for descriptions of appropriate data or check whether inches are entered in lieu of feet, pounds in lieu of kips, or vice versa etc.

0044: Once I have saved and closed a project file, can I return later to change the project name or designer?
No. You will have to re-run the module with the new project name or designer and re-enter the data. You may, however, revise the entry data in a new or existing project file at any time, in which event re-calculation will be executed automatically.

0046: Why is the Print button in my Excel File Menu disabled when a Modstruct module is running?
The normal print button is temporarily disabled so that it will not be accidentally or inadvertently used instead of the module-activated PrintResults button which is enhanced to provide custom formatting of the printouts.

0047: How do I obtain a printout of the entry data, calculations and results?
Clicking on the PrintResults button of the menu at the top of the screen will offer a choice of printing on a color printer where all user-derived entry data will be colored blue or a mono printer where all user-derived entry data will be shaded. In both cases, all values calculated by the program will appear in black. Should the printout occupy more than one sheet, the entry data and final results will be printed on the first sheet while the intermediate calculations will be printed on the remaining sheets.

0048: Why is the first page of the printout (and each of the other pages, if any) being printed on more than one sheet?
Click File -> Page Setup -> Margins.
Set Left = 1, Right = 1, Top = 1, Bottom = 1, Header = 0.5, Bottom = 0.5  -> OK.
Click File -> Print Preview.
If the problem persists, reduce the margin which appears to be the source of the problem and verify with File -> Print Preview.

0049: How do I obtain a printout of the Diagram, ReadMe or Notation sheet?
Click on the PrintOthers button of the menu at the top of the screen and select the Diagram, ReadMe or Notation button.

0060: Having acquired the latest edition of a program, why would I want a downgrade?
Have you ever been rapped on the knuckles by a Plans Examiner for citing the latest edition of a model code which has not yet been adopted by his jurisdiction? Strictly speaking, your notes and specifications should refer to the standards referenced in the adopted edition of the model code and your calculations may need to be consistent therewith.

0061: How can these programs be be used as learning tools?
The accessibility for your review of the underlying equations and the conditional statements in the calculation cells constitute a powerful learning tool for both structural engineering design and Excel programming techniques which you may find useful for designing your own custom spreadsheet solutions. Additionally, engineering students can study these modules to gain valuable insight into design office practices.

Sundry questions on Metal Deck Diaphragm

1301a: How do I obtain the lateral load on the edge of a diaphragm?
The total lateral force or the uniformly distributed lateral load on the edge of the diaphragm may be obtained by manual calculations or from a computer program such as WBldg-02 (see FAQ #2312a).

Sundry questions on Wind Forces at Base of Enclosed and Partially Enclosed Rigid Buildings of All Heights

2312a: How do I determine the uniformly distributed wind load on the edge of a floor diaphragm?
In WBldg-02, for a floor diaphragm, enter under z.2 the elevation of the mid-height of the story above the floor, and under z.1 enter the elevation of the mid-height of the story below the floor. The corresponding value under H.021 will be the total shear (kips) in the diaphragm. The uniformly distributed load (kip/ft) on the edge of the diaphragm will be this total shear (kips) divided by B (ft), the building dimension normal to the wind. 

2312b: How do I determine the uniformly distributed wind load on the edge of a roof diaphragm?
In WBldg-02, enter under z.2 the eave height of the building, and enter under z.1 the elevation of the mid-height of the story below the roof. The corresponding value under H.021 will be the roof diaphragm shear (kips) due to wind forces below the eave which is to be added by hand to the pre-calculated H.021 value in cell I39 (the roof diaphragm shear due to wind forces above the eave). The uniformly distributed load (kip/ft) on the edge of the diaphragm will be the total shear (kips) divided by B (ft), the building dimension normal to the wind.

2312c: How do I determine the story shears and moments in a building?
In WBldg-02, the shear for each story and the roof will be the respective value under H.021 (kips) obtained in 2312a and 2312b above and the moment will be the respective value under M.021 (ft-kips). The sum of the shears for all stories and the roof should be equal to H.0 and the sum of the moments for all stories and the roof should be equal to M.0 .

2312d: How do I determine the horizontal or lateral wind force on a roof truss anchor?
Obtain the uniformly distributed wind load (kip/ft.) on the roof diaphragm edge in the manner described in 2312b, multiply this quantity by the roof truss spacing and divide by the number of anchors resisting lateral shear to arrive at the horizontal shear in kip(s) per anchor.

Sundry questions on Wind Pressures on Components and Cladding of Enclosed and Partially Enclosed Buildings up to 60 ft.

2322a: What is the correlation between wind pressures on components and cladding obtained by the analytical method of ASCE 7-02 and the simplified wind pressures of the IBC 2003 Table 1609.6.2.1 or the FBC 2004 Table 1609.6?
The simplified wind pressures of the model codes are basically expanded versions of the ASCE 7-02 Fig. 6-3, the Simplified Procedure table applying to enclosed buildings only. The wind pressures in all of these tables are derived by the analytical method on the basis of prototype values assigned to a number of parameters listed in Sec. C6.4 of the Commentary. Provision is made for adjustments for height and exposure. Other than that, the applicability of the Simplified Procedure is limited to the conditions dictated by the prototype parameters. To re-create the tables using your favorite components and cladding program such as Modstruct's WCladLo-02 or by manual calculations, enter a basic wind speed 85-170 mph, a wind directionality factor Kd=0.85, a building classification=2 (importance factor I=1.00), an exposure category=B (Kh=0.70), a topographic factor Kzt=1.00, an enclosure classification=enclosed (internal pressure coefficients GCpi=+/-0.18), a mean roof height h=30.00' (for each roof slope, you may need to manipulate the eave height and the least horizontal dimension of the building to obtain the 30' mean roof height), a roof slope of 0 degree (representing the interval between 0 and 7), or a slope of 20 degrees (between >7 and 27), or a slope of 40 degrees (between >27 and 45). The tabular wall pressures are obtained from the run using a roof slope between 7 and 27 degrees. Your results should match the corresponding values in the Simplified Procedure tables. Be aware that the use of the 0.85 wind directionality factor implies that these wind pressures will be used in the basic load combinations of Sections 1605.2 & 1605.3 of IBC 2003 or FBC 2004.

2322b: Why must the load combinations of Sections 1605.2 & 1605.3 of IBC 2003 or FBC 2004 be used in conjunction with the 0.85 wind directionality factor for components and cladding from ASCE 7-02 Table 6-4?
Because the 0.85 factor is calibrated with the load combinations of ASCE 7-02 Sec. 2.3 & 2.4, Section 6.5.4.4 as well as the footnote of Table 6-4 stipulate that it shall be applied only in conjunction with those load combinations. The basic load combinations of Sections 1605.2 & 1605.3 of IBC 2003 and FBC 2004 and of Sections 9.2 & 9.3 of ACI 318-02 are all compatible with the ASCE 7 combinations.

2322c: Why would there be differences in the wind pressure values between one computer program and the next?
Barring programming errors, there may be minor differences because, for instance, one program uses the stepped values of ASCE 7-02 Table 6-3 to determine velocity pressure exposure coefficients while another program such as Modstruct's WCladLo-02 uses the more precise Equation C6-3 of the Commentary. The method described in FAQ #2322a to re-create the Simplified Procedure tables should be a good check on the accuracy of your favorite components and cladding program.

2322d: What is the difference between the effective wind area and the tributary area of a component?
The effective wind area, which is used only to determine the average wind pressure on a component, is the span length L multiplied by an effective width B which need not be less than one third of the span and is therefore equal to the greater of LxB or L squared divided by 3. The total wind load acting on the component will be the average wind pressure multiplied by the tributary area which is simply LxB. However, for cladding fasteners (nails, screws etc.), the effective wind area shall be equal to the tributary area.

2322e: How can I use the WCladLo-02 module to schedule wind pressures on windows and doors?
After entering the data for the building as a whole, determine the effective wind areas corresponding to the various window and door sizes and enter them in the A.e column of the program. Then select the negative and positive pressures, 5N and 5P, for all openings within the corner zones having the zone width a.z and 4N and 4P for all openings within the interior zones which lie between the corner zones.

2322f: Where can I obtain the wind pressures on balconies, canopies and carports attached to a building?
Because wind pressures on balconies, canopies and carports attached to the main structure are not addressed in ASCE 7, it should be at the discretion of the designer to use the roof overhang pressures (Zones 1No, 2No and 3No in WCladLo-02) even if the slopes are different from the main roof slope. Note that the roof overhang pressures include contributions from both the upper and lower surfaces.

2322g: How can I find the uplift force on a roof truss anchor?
WCladLo-02 delivers only the wind pressures (psf or lb. per sq. ft.) on various effective wind areas of components and cladding. The determination of wind forces (lb) goes beyond the scope of this program. However, for those who still need a little nudge on this question, the example of HowDoI? #H2322 may assist your understanding of the issues to be addressed.