| Q1: |
I'm trying to run the Mac version of WPBD and it's not working. What to do? |
A1: |
WPBD installs best using an account with Administrator privileges. If you're working in a lab or other environment where you don't have Administrator privileges, seek the help of a system Administrator.
Still not working? WPBD requires a 64-bit Intel Mac running OS X 10.6 or later and Java 1.6 or later. If WPBD is not working for you, we suggest the following steps: Update Java at http://support.apple.com/kb/DL1360. Temporarily disable your virus checker. Move the bad WPBD installation to Trash. Download a fresh copy from http://bridgecontest.usma.edu/download.htm. Re-install. Give WPBD a test run. Re-enable your virus checker and initiate a scan.
Special notes for OS X 10.7 Lion: Though WPBD is not extensively tested on Lion, many Lion Macs are running it successfully. Lion does not include Java as earlier OS X versions did, but it can easily be installed as an update. See http://support.apple.com/kb/DL1421 in case Lion does not initiate a download automatically during WPBD installation.
Still not working? Write wpbedc1@gmail.com for more help. |
| Q2:
|
I'm trying to run the Windows version of WPBD and it's not working. What to do? |
A2: |
WPBD installs best using an account with Administrator privileges. If you're working in a lab or other environment where you don't have Administrator privileges, seek the help of a system Administrator.
Still no luck? The WPBD requires Windows XP, Vista, or Win 7 in either 32- or 64-bit versions. Java 1.6 or later must be installed. If WPBD is not working for you, we suggest the following steps: Bad graphics driver software is the likely cause of the problem. Installing the most recent graphics drivers from your computer or graphics card manufacturer will often provide an immediate fix.
Additional steps if there is still a problem: Update Java at http://www.java.com/en/download/index.jsp. Temporarily disable your virus checker. Uninstall WPBD using the icon in the WPBD folder of your Start menu. Download a fresh copy from http://bridgecontest.usma.edu/download.htm. Re-install. Give WPBD a test run. Re-enable your virus checker and initiate a scan.
Still not working? Write wpbedc1@gmail.com for more help. |
| Q3: |
The software runs fine in the Drawing Board mode, but the Load Test animation doesn't work at all. The screen is blank, the computer freezes, or a box appears saying that the graphics system has failed. What to do? |
A3: |
WPBD uses your graphics card aggressively, just as advanced computer games do. Conseqeuently, it is sensitive to graphics driver software problems.
Try starting the Bridge Designer with the icon titled "West Point Bridge Designer 2nd Edition for older computers."
Still no luck? Download and install the latest version of drivers for your graphics card or computer. If you don't know how to do that, consult a computer technician or your computer manufacturer's web site.
Still no luck? Write wpbedc1@gmail.com for more help. |
| Q4: |
I'm using the Mac version of WPBD. It works fine, but it's different from all my other Mac applications. Can't you make WPBD fit better in the Mac environment? |
A4: |
Maybe. We have very limited resources for Mac compatibility. Some Windows look and feel is therefore present in the Mac version. One example: if you use menu "Meta" accelerator key combinations (like Meta-S to Save), you'll have to switch to replace Meta with Control in the Bridge Designer. Sorry about this. If you have a pet compatibility issue, please post to our discussion group at http://kenai.com/projects/wpbdc/forums/discussion. We'll consider it. |
| Q5: |
How
can I learn how to use the West Point Bridge Designer? |
|
A5:
|
Start
up the West Point Bridge Designer, and click the Help menu.
Then click "How to Design a Bridge," and follow the
step-by-step procedure provided. |
| Q6:
|
In
WPBD, which deck elevation, support configuration, deck material, and loading do I use to enter
the contest? |
|
A6:
|
You
may use any available deck elevation, support configuration, deck material, and loading.
Each of these
configurations has a different site cost, and each will significantly affect the cost of your bridge structure. Your challenge
is to find the one that results in the lowest possible total
cost. |
| Q7:
|
May
I make additional copies of the West Point Bridge Designer and
distribute the software to others? |
|
A7:
|
Yes.
The West Point Bridge Designer is in the public domain. You
may make unlimited copies of the software, and you may freely
distribute copies to others. |
| Q8:
|
May
I use the West Point Bridge Designer to design an actual bridge? |
|
A8:
|
No. The
West Point Bridge Designer is intended for educational use
only. The loads, structural analysis methodology, and design
algorithms used by this software have been simplified considerably
from the procedures used to design actual bridges. Using
the West Point Bridge Designer to design a real structure
would be both dangerous and irresponsible. If
you need to design an actual structure, you must obtain
the services of a registered professional engineer.
|
| Q9:
|
How
can I reduce the cost of my bridge design? |
|
A9:
|
To
reduce the cost of your design, you'll need to learn a few basic
principles of structural engineering. To do this, start up the
West Point Bridge Designer, and click the Help menu, then click
"How to Design a Bridge." On the flowchart, click
the boxes labeled "Optimize the Member Properties,"
"Optimize the Shape of the Truss," and "Find
the Optimum Truss Configuration." Read these sections carefully.
They contain suggested procedures and a number of hints to help
you reduce the cost of your design. |
| Q10:
|
Why
does the cost of my design go up when I reduce the size of a
member? |
| A10:
|
To understand
the answer to this question, you need to understand how WPBD
calculates the cost of your truss. Run WPBD and load any of
the sample bridge designs. Now click the Report Cost Calculations
button, located on the Status toolbar. WPBD will display a
table showing exactly how the current cost of the truss has
been calculated. You'll see that the total cost is composed
of three components--material cost, connection cost, and product
cost. When you reduce the size of a member, you reduce its
material cost. However, for each new "product" you
add to your design, you are charged an additional $1,000. A
"product" is defined as any unique combination of
material, cross-section, and size.
This cost
algorithm is fairly realistic. If you optimize a structural
design by making every member as small as it can possibly
be, you'll end up with a very light but very impractical structure.
It will be impractical because it will consist of many different
member sizes. When a construction company actually has to
build a structure like this, the project will incur a lot
of additional cost. It's harder and more expensive to join
two different sized members together than to connect two identically
sized members. There is also a cost associated with having
to order and manage many different member sizes on a job site.
In short, there can be substantial cost saving associated
with standardization--using as many of the same sized members
as possible in a structure.
This is
not to say that using the same member size for all of the
members in a truss will produce an optimal design. It won't!
There is a tradeoff between light weight and standardization.
You need to do some trial and error to find the best balance
between the two. Reducing the size of a single member might
cause the total cost of a truss to rise; however, simultaneously
reducing the cost of five members will almost certainly cause
the total cost to drop, because you reduce the material cost
for all five members but add only a single additional $1,000
product cost.
|
| Q11:
|
My
bridge design is perfectly symmetrical, but the load test results
on one side are different from those on the other side. Is this
a bug in the software? If the bridge is symmetrical, shouldn't
the load test results be symmetrical too? |
| A11:
|
This
is not a bug in the software. In order to have symmetrical load
test results, three conditions must be present: (1) the structure
and all its members must be perfectly symmetrical, (2) the supports
must be symmetrical, and (3) the loading must be symmetrical.
In WPBD, the supports are symmetrical for some, but not all,
of the 54 site configurations. And the loading is never
symmetrical when the AASHTO H25 truck loading is used. The H25 loading has a heavy axle
(the rear one) and a light axle (the front one). Since the truck
only crosses the bridge in one direction, the asymmetrical loading
causes small differences in the load test results for identical
members on opposite sides of a symmetrical bridge. For more
information, click the Help menu in WPBD, then choose "Help
Topics" and look up the topic, "What is Not Realistic
about WPBD." |
| Q12: |
My
bridge bends too much. Shouldn't that be considered in judging
whether or not a design is successful? |
| A12: |
In the
West Point Bridge Designer, your design is judged to be successful
if it passes the load test--if the truck is able to drive
completely across the span without causing a collapse. Thus,
to be successful, your structure must have adequate strength.
In evaluating your design, WPBD does not consider how much
your bridge bends.
Actual
bridge designers do, in fact, consider whether or not the
displacements of the structure are too large; however,
large displacements are not a safety concern. Displacements
are considered in structural design only because excessive
movement of a structure tends to make people feel uncomfortable--no
matter how strong the structure actually it is.
In any
case, your design probably does not bend too much. It only
looks that way! In the WPBD Load Test Animation, the displacements
are exaggerated by a factor of 10. The purpose of this exaggeration
is to illustrate how tension and compression
in individual structural members cause the entire structure
to bend. If you would like to see how much your bridge would
actually bend if it were built, click the View menu in WPBD.
Then select "Load Test Display Options..." and uncheck
"Show Exaggerated Displacements."
|
| Q13: |
Is it possible to do a silent installation of WPBD? |
| A13: |
Yes. For the Windows installation, the command is setupwpbdv11j /S. |
