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5.11 WEB-BASED INTERACTIVE DESIGN
OF BEAMS
The applet for interactive design of
simply-supported steel beams (including beams with left and right
overhangs) consists of Input and Results panels shown in Figures 5.14
and 5.15, respectively. A separate configuration panel is displayed at the
bottom of these panels. We have avoided using a toolbar and a scrollbar in
order to reduce the screen size of the applet so that the users whose
screen resolutions are set at less than 800X600 can still view the entire
applet without scrolling. The user can toggle back and forth to different
panels by clicking on the corresponding tab attached to them.
While
the student is entering input values in the input panel the inputted values
will be displayed immediately on the beam configuration panel. The
locations of the supports and lateral bracing points are entered one at a
time using the Add button. The
values can be reset at anytime using the Reset button. The loading can consist of a distributed load of
uniform intensity on the entire span or any portion or portions of the span
and any number of concentrated loads. The basis of design can be AISC ASD
(AISC, 1995) or AISC LRFD (AISC, 1998) specifications. For the latter it is
necessary to input the dead and live load components separately.
The student can choose the nominal depth of the section and ask the applet
to find the lightest section with that nominal depth, or ask the applet to
come up with the absolute lightest section irrespective of the nominal
depth. The student can select any steel type provided in the AISC ASD or
LRFD manuals. Section type can be W shape, M shape, S shape, HP shape, WT
shape, C shape, or MC shape.
This applet as well as all other
applets created for the course are intended to let the student perform the
design with the minimum amount of data entry. Building upon the idea of the
Redesign Menus presented in Adeli
(1988), the user can perform redesigns repeatedly by simply changing only
one or several of the input values. Based on the information obtained from
the initial design, the user can modify or limit any design parameter and
request a new design without the need to start all over again. This is an
effective tutorial feature considering the open-ended nature of the design
problems. The student can find the answers to a lot of what-if scenarios in
a very short period of time. This not only boosts the learning experience
tremendously but also makes it more interesting.
The
results panel displays all the necessary and useful information including
the shear diagram, the bending moment diagram, the magnitude of the maximum
bending moment, the location of the maximum bending moment, and the
cross-section of the selected member with all the dimensions for the
selected design approach. Further, it will also show the answer based on
the other design approach. In Figure 5.15, for example, the user has
selected LRFD for the basis of design. But, the design on the basis of ASD
is also presented as well as the relative magnitude of weight savings. The
comparison of designs based on the ASD and LRFD codes enhances the design
feel and experience of the student.
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