Multiframe includes capabilities for automatically generating commonly used frames. The four facilities provided are for standard bay and storied frames such as those found in multi-story buildings, portal frames as used in many buildings with sloping roofs, continuous beams and curved structures.
§ Choose Generate… from the Geometry menu
A dialog box will appear with the a list of structures that can be generated.
§ Select 2D portal item from the list and click OK
A dialog box will appear allowing you to enter the dimensions of the frame.
§ Enter the values for the width, column height and the slope of the rafters
§ Enter the values number of portal bays
§ Select the type of restraint to be applied to the joints at the base of the columns
§ Click the OK button
The pitched portal frame you generate will be shown in the Frame window.
§ Choose Generate… from the Geometry menu
A dialog box will appear with the various generation icons in it.
§ Click on the multi-bay frame icon and click OK
A dialog box will appear with fields for the spacing in each direction. Bays run in the x direction, stories in the y direction and frames in the z direction.
§ Enter the values for the number of structural elements and the dimensions in each direction.
§ Enter the values for the number of secondary and tertiary beams in each bay of the frame.
§ Select the direction of secondary beams
§ Click the OK button
The frame you generate will be shown in the Frame window.
You may also find this command useful for generating the initial geometry for other structures such as trusses. You can start by generating the appropriate number of bays, 1 frame and 1 story.
You can then use the other drawing and duplication tools to create the structure you require e.g.
Multiframe allows you to quickly generate a continuous beam which is made up of a number of even or varying length spans.
To generate a continuous beam
§ Choose Generate… from the Geometry menu
A dialog box will appear with the various generation icons in it.
§ Click on the continuous beam icon and click OK
A dialog box will appear with a table in it.
§ Type the number of spans in the beam
§ Click on the first length value in the table to select it
§ Enter the lengths for each of the spans using the Down Arrow key to move down the table
§ Select the restraints to be applied to internal joints along the continuous beam.
§ Select the restraints to be applied to the joints at the ends of continuous beam.
§ Click the OK button
Multiframe will automatically generate the beam with the dimensions you have specified.
Multiframe allows you to quickly generate an approximation to a curved member by generating a number of short straight members.
To generate a curved member
§ Choose Generate… from the Geometry menu
A dialog box will appear with the various generation icons in it.
§ Click on the curved beam icon and click OK
A dialog box will appear allowing you to enter the angles and radius of the beam.
§ Type the coordinates of the centre of the arc, radius and angle of sweep using the Tab key to move from number to number
§ Type in the number of members you would like to use to approximate the curve
§ Click the OK button
Multiframe will automatically generate the assembly of members with the dimensions you have specified. The direction of the arc will depend on the current view in the Frame window. The arc will always be generated about the axis that is perpendicular to the screen or in the case of the 3D view, about the axis that is most perpendicular to the direction of view. This axis is not drawn in bold on the axis indicator.
Normally you will want the new members to connect with any existing members in the structure. If you do not want this to happen, uncheck the check box at the bottom of the dialog.
It is probably a good idea for you to test the accuracy of this approximation to a curve, by generating arcs with different numbers of members and examining the effect this has on the results of analysis.
Multiframe allows you to quickly generate a regular frame that is made up of a number of evenly spaced, similarly shaped sub-structures. Typical examples of this would be high-rise buildings, trusses or multiple bay portal frames. Multiframe also allows you to duplicate shapes in cylindrical and spherical coordinates.