[From Aegis] LINK Updates

This is from an email sent by Jayna Altman on Tuesday, March 24 2009.

To all Link Users,

Today, we updated our "Submit a Job" form for Pre-Approved Labeled Standards. The list of details to select from will now reflect our current list of all standards that we offer. You will notice that some details were removed from that list and replaced with a new detail. We have attached a spreadsheet to help you determine the new replacement detail for any old detail that you may have been using.

If you have any questions, please contact Aegis Engineering Department.

As always, “Thank you” for your continued business!

I've copied the Updated Detail spreadsheet here.

Manufacturer Basics

One problem that seems to pop up every so often involves Manufacturer Basics.

The idea behind Manufacturer Basics is straightforward--these are your default settings that form the starting point for all new projects. You can specify things like steel end cuts, normal loading, etc. New projects should, in theory, use these settings as the "parent" of the Job Basics.

Unfortunately, this "Parent - Child" relationship is only used if you create new truss projects within the Design program (File, New Job). If you simply open an existing folder in Design (since a Job is equivalent to a folder), Design will create a new Job Basics file (job.var) if one does not exist. Most of the time, jobs/folders are already existing when the design process is ready to be started.

So this nice step of creating Job Basics based on Manufacturer Basics rarely occurs. Instead, Design uses a recent job.var file to create the new one--which can carry over loading and other settings from one project to the next. There's no telling who's the "Parent" of your "Child". I'm pretty sure there's some bad jokes there, just waiting to be made.

Worse yet, sometimes things like fastener settings can become corrupted or incorrect. Once that happens in one project, it can spread to all subsequent projects. Problems like that can be tedious to fix.

The best solution? Always check your Job Basics before designing (or importing) the first truss.

Truss + Bracing Cost

When designing trusses, we want to minimize cost. Part of that involves reducing the truss cost as much as possible. We do this by making changes in the Design program, analyzing the truss, and then comparing the cost in the "Analysis Results" window to the previous version. If the cost is lower, we save the truss and keep trying until we're satisfied we've reached the best price. If the cost is higher, we discard those changes, and keep trying.

However, the total cost of a truss includes more than the material, screws, labor, etc. It also includes the cost of the lateral web bracing. Normally, USC trusses are less expensive, but require more bracing. USD trusses are more expensive, but require less bracing. The designer's job is to find the best balance of those options.

To that end, I've created a simple spreadsheet that calculates the total cost of a truss design, including lateral web bracing. The link is here. Once you have a working TRZ in the Design program, you can use this spreadsheet to find the most cost-effective option.

Here's how to use it:

1. Enter the Basic Info (Truss Spacing, Truss Quantity).
2. Enter the Total Cost (for all trusses, from the Analysis Results window) into the Total Cost column, in the row of the first iteration.
3. Count the number of Braces onscreen, enter the number in the Braces per single Truss column.
4. Try to modify the truss in Design in order to make it more cost-effective.
5. Enter the new Total Cost and number of Braces into the next iteration row.
6. Repeat steps 4 & 5, keeping cheaper designs, discarding more expensive versions, until you've reached the best outcome.

I hope that this explanation is clear and useful. Please let me know if you have any other suggestions for this tool, or ideas for other tools that would make our Design process better.

Inventory in Design (Update)

Turns out that our idea about using the "Inventory Length" settings in Aegis Design will not work.

Here's the problem: selecting only the stocked and available chord lengths caused errors with the Material Summary from the Summary program. The Material Summary normally produces a list of the steel needed for the selected trusses, broken down into one-foot increments. For example, the list will look sort of like this:



However, when we only had 32' checked in the "Inventory Lengths" in Design, Summary would list all these pieces as 32' long. Which then created a significantly higher Total Lineal Feet value. Which caused all sorts of confusion. This also happened for 35, 55, and 725 chords, both USC and USD.

Phil Neely at Aegis says this was not a known issue. We will be trying to re-create this error on both ends, so that Aegis can work on fixing the problem in future releases.

So for now, we are abandoning this experiment. Thanks to Pedro Hernandez for discovering and pointing out the problem.

Update: according to Phil Neely, this is not a bug. It's a feature. The "Inventory Length" code was written to round all lengths up to the nearest available length. This shows up in costing in Design, and well as on the Material Summary.

Given that information from Aegis, I'm not sure what purpose the "Inventory Length" tool has. I don't see any advantage to using it.

Quality Assurance Links

As most of you are aware, we've set up some online documents for managing Quality Assurance. You will find these links on the right-hand side of this page, but here is a little more info on each:

• Submission Form - this is the form where designers submit projects for review.
• QA Status - this is the page that lists all the jobs that have been submitted for review. It also contains a link to the review comments.
• Blank QA Notes - this is the blank form we use to review each project. It may be worthwhile for each designer to be familiar with this form, so that some problems can be caught before submitting for review.

It is our hope that the QA process is clear, straightforward, and useful. Please feel free to suggest other items that we should be checking!

Manual Web Patterns

One useful tool for creating exactly the truss design you need is the Manual Web feature in Profile.

If you look at the picture to the left, you will see a check box for "Auto Web" at the bottom of the Profile dialog box.

Un-checking this box will cause the program to pause after you click "Build". The program will prompt you to create a web pattern by clicking from joint-to-joint.

This can be very useful for controlling whether webs are in tension or compression, and also to override the normal web patterns produced by the program algorithms.

Unfortunately, there is a bug in Aegis Design 8.05 that will cause the program to crash when "Auto-Web" is turned off for a truss with a cantilever. Aegis is aware of the problem, and it will be corrected in the next release. No word on when that will be.

Vertical Dimension Lines in Design

Did you know that you can choose any vertical lines to be dimensions lines in the Aegis Design program?

To see for yourself, open Versatruss and select any vertical line. The lines do not need to be defined as "Vertical"--"Parallel" to a vertical line, or "Dividing" two vertical lines will work also.

Then, click on the "Dim Info" button on the Versatruss window. The dialog box at the left will appear. You can then choose to set the selected vertical line to appear as a dimensioned point on the top chord dimension line or the bottom chord dimension line.

In addition, you can also choose to set the selected vertical line as the origin ("Y-axis") of the horizontal dimension line.

Spellcheck in AutoCAD

Did you know that AutoCAD can check your spelling? Try typing "SPELL" in the command line, and you will see.

I've been trying to do this for jobs that I'm reviewing. I've only found a few major mistakes--but I've found many minor mistakes. Many of the details that are part of each drawing template contain a lot of text--and that text contains several spelling errors.

It would be a good idea if each of us took a few minutes and ran Spellcheck on our drawings whenever finishing a project. Many of these small errors can be corrected once, and then never be seen again.

Will spelling errors ever result in a backcharge? No--but it won't make us look better than our competition.

Creating Truss Objects in AutoCAD

One of the small annoyances of the Aegis Layout program involves the way it exports trusses into the DXF. Each truss will come in as six line segments, which can create problems when you're trying to shift trusses around your layout in AutoCAD.

I used to delete those short little lines at the ends of the truss--better to not have them at all, than to have them get left behind after I've moved the rest of the truss.

Now, I have a better solution:

1. Open the Aegis Layout DXF in AutoCAD
2. Turn off all layers except the truss layers
3. Type "PEDIT" in the command line
4. Enter "M" for "Multiple"
5. Select all the lines that make up the trusses
6. Enter "J" for "Join", use a zero fuzz factor

After the command finishes, I am left with a single polyline for each truss.

The polylines do still have six segments, so I still need to be careful when dimensioning. However, the ease of moving those trusses around makes it worth it!

Versatruss Member Names

In Versatruss, each piece of steel and each reference line has a unique name. Here is a partial list of the common member names, and a short description of each:

Steel Members:

B bottom chord, numbered from left to right.

C connector plate or bearing block.

EV end vertical, numbered from left to right.

T top chord, numbered from left to right.

W web, usually numbered from left to right.

Reference Llines:

A seems to be the standard name for general-purpose reference lines. "A" lines are used often as end cuts. Also, user-added lines will be name with an "A".

DB defines a bottom chord panel point. These lines are create at each bottom chord joint in Profile. If you move one of these lines, the webs defined by it will also move. Profile will not reflect the change. This can be a useful way to tweak a truss without going to Profile.

DT defines a top chord panel point.

H0 is the vertical "y-axis". It does not appear in the member list, but it is used to define other members.

PB defines a bottom chord pitch break.

PT defines a top chord pitch break.

OH defines the end cut of a top chord at the overhang.

SL is a vertical line through the point where the top of the bottom chord intersects the bottom of the top chord. For trusses with standard heels, this line will be the left end cut of the bottom chord.

SR is similar to SL, on the right side of the truss.

V0 is the horizontal "x-axis". It does not appear in the member list, but it is used to define other members. The intersect of H0 and V0 form the origin point of the truss design.