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8.4 WEB-BASED INTERACTIVE DESIGN OF CONNECTIONS
8.4.1 Design of Simple Bolted Beam-Column and Beam-Girder
Connections
Fig. 8.19 shows the initial screen of
the applet for design of simple bolted beam-to-column and beam-to-girder
connections according to the AISC ASD specifications. This applet consists
of three panels: Input panel, Results panel, and Graphic View panel.
The user can enter the connection design input in the input panel (Fig.
8.19). This input includes selection of the W (wide flange) shapes for beam
and column, angle, bolt type (bearing type with threads excluded or
included versus slip critical type), connection type (bearing type with
threads excluded or included in the shear plane versus slip critical type),
bolt hole type (standard, oversized, short-slotted, or long-slotted), bolt
diameter, bolt spacing, number of bolts, and entering the end reaction. Two
types of bolted connections are included: beam-to-column and
beam-to-girder. The applet can design the connection, check the adequacy of
a given connection for a specified beam end reaction, or calculate the
shear load-carrying capacity of a given connection.
The
user is allowed to choose among the 295 W shapes available in the AISC
manuals (AISC, 1995 & 1998) for the beam and column. A two-step input scheme
is used to minimize the input entry by the user (Fig. 8.20). In step 1 the
user is asked to select a nominal depth. In step 2 the user is asked to
select the weight per unit length among the members with the selected
nominal depth. The user also selects the type of the steel and the
connection assembly gap (the clear distance between the beam and the
column).
In
the input panel the user selects the angle size, thickness, and length, the
connection type, the bolt type, the hole type, and the diameter and the
spacing of the bolts. Fig. 8.19 shows the default values for the angles and
the bolts. The user can skip choosing any one of these sizes. In that case,
the applet designs the lightest angle and the smallest bolt sizes using the
commonly used increment of 1/8 in. A two-step scheme is also used for
selection of the angle as shown in Fig. 8.21. Fig. 8.22 shows the results
panel for finding the load carrying capacity of a simple beam-to-column
bolted connection (for the example data given in Fig. 8.19). Fig. 8.23
shows the graphic view panel for this connection.
Figures 8.24, 8.25, and 8.26 show,
respectively, the input, results, and graphic view panel for a simple
bolted beam-to-girder connection. The results and graphics view of Figs.
8.25 and 8.26 are found based on the example data in Fig. 8.24. In this
case, the applet designs the beam-to-girder connection with the least amount
of data entered in the input panel.
These figures display all the
necessary details and useful information. A perspective view of the connection
and front view and details of the connection with all the dimensions are
displayed in the graphic view panel. The front view and details are
generated by the applet in real time after the connection design is
completed. The perspective view, on the other hand, is not drawn by the
applet. It is a generic figure placed on the server where the applet source
bite code resides.
Whenever the user clicks on the tab
attached to the graphic view panel, the applet downloads the perspective of
the connection from a database of connection perspectives stored on the
server (Fig. 8.27). This approach saves time for real-time generation of a
perspective view by the applet which involves a large amount of
computations. To expedite the time for downloading of the perspective view,
the size of the GIF formatted file for each perspective view is limited to
3 to 4 kilobytes so that it can be transferred in less than a few seconds by
the applet when the on-line connection is through a slow telephone modem.
This is done by simplifying the connection perspective views and avoiding
or minimizing the use of the color in displaying the perspective view.
By
keeping the size of the applet relatively small the time required to
download the applet itself is also reduced. Furthermore, the database of
the perspective views for various connections on the server can be
maintained and updated without the need to revise the source codes of the
applets.
8.4.2. Design of Simple Welded
Beam-Column Connections
Similar to the applet for design of
simple bolted connections the applet for design of simple welded
connections also consists of three panels: Input panel, Results panel,
and Graphic View panel.
The
user enters the connection design input in the input panel (Fig. 8.28). This
input includes selection of the W (wide flange) shapes for beam and column,
angle, weld size and electrode, and entering the beam end reaction. The
user can also choose between two options: design or compute the
load-carrying capacity of the connection.
The applets accept legal practical values only. For improper or impractical
input values a warning or pop-up message will be displayed and the user
will be asked to reenter/re-select the input. Other bits of information and
knowledge are also displayed to guide the user in the design process. As an
example, when the user chooses a weld size of greater than 5/16 in. the
pop-up message shown in Fig. 8.29 will be displayed.
A summary of final connection design
is presented in the results panel (Fig. 8.30). A perspective view of the
connection and two side views of the connection with all the dimensions are
displayed in the graphic view panel (Fig. 8.31). The results shown in Figs.
8.30 and 8.31 are for the example data given in Fig. 8.28.
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