Manually designing a Member

 

The manual design of a member is carried out under the Section Autodesign tab. The member to check is selected in the graphics pane, with the member to be checked selected by using the mouse pointer and left-clicking. The selected member will highlight in red and the member will be shown in the frame in 3D, even where the 3D drawing option is turned off. The current section information will be shown in the Section AutoDesign area in the bottom pane.

 

A typical layout of design brief for a selected member is shown below. The selected member is highlighted in red in the graphics pane. The selected member has a Beam & Beam Portion brief attached to it, and the member is showing a design failure in the Lateral Buckling Check. A design failure is indicated by a cyan background in the design pane, and the specific check that the member is failing is noted with the message "Warning", shown in red text.

 

 

 

 

The section type, steel grade and section size can be selected using the

 options. To select a section size, the section drop down can be expanded by clicking on it with the mouse. Alternatively, the sections can be scrolled through using the  spin buttons. Sections are normally sorted by section size and weight. However, clicking on the  icon will sort the sections be weight only.

 

In addition to the section type and section size options, within the Section AutoDesign it is possible to amend various properties for a section using the

 icons. These icons allow:

 

 - double members. Uses the currently selected section type to create 2 side by side members. When selected the option to specify the spacing of the members becomes active.

 

- concrete encasement. Considers a concrete encasement around steel members only. This allows a modification of the lateral torsional buckling resistance of the member. When selected, options to define the width b and height h along with the concrete grade become active. Note - a minimum of 50mm concrete cover is required before the encasement will be considered effective.

 

 - compound section. Allows the chosen section to be modified to accommodate flange plates (top and/or bottom) and to define the projection of the plate relative to the beam. In addition, this option also allows for the addition of a steel member channel to add to the top flange of the beam, or to add an open "I-section" to the web to resist the minor axis moments. In this case the axial and major axis bending is resisted by the main section while the minor axis moment is resisted by the secondary section.

 

 - cellular section. Creates a cellular section from the original section. In the case of standard I-sections, the cellular beam will be "created" by cutting the original size and welded together. This will result in an increase in the section depth from the original section size. When the original section is specified as a Built-up & ASB, where a plated section is specified, the openings in the web are assumed to be cut without altering the dimensions of the input section size.

 

 - Discrete web openings. Creates circular, rectangular or elongated openings through the web of beams. For further details on this option, refer to the MasterFrame manual.

 

 

In the screen image above, the beam is noted as failing - this is indicated by a blue background in the calculation area. Since this is a primary beam, the lateral restraints can be taken at the positions of the incoming secondary beams. Using the

in the Lateral Restraint tab, the design outputs now updates as shown below.

 

 

The summary area now notes that the member ultimate limit state utilisation ratio has reduced to 0.337. Hence the beam section can safely be reduced using the steps noted above.

Alternatively, the positions of lateral restraints can be entered manually. The portion length is the distance between restraints.