When performing a bending check, you may need to specify the location and type of lateral restraints acting on the member.  It is also necessary to enter the stiffener's information.

To determine the moment member capacity of a member, it is necessary to know the spacing of any lateral restraints (if any) along the member. The restraints could be provided by purlins, girts or other structural elements which are not modelled in Multiframe. Steel Designer uses this information to determine the length of segments used in the design calculations. The lateral restraints acting at a particular section on a member are dependent upon which flange is the critical flange. For a member/segment restrained at both ends the critical flange is the flange under compression. For a cantilever or a segment with an unrestrained end, the critical flange is the tension flange. For each restraint on the member, the user must specify the type of restraint. As this depends upon which flange is the critical flange, the user must specify the type of lateral restraint that would be present at a section if

     i) the top flange were the critical flange, and

     ii) the bottom flange was the critical flange.

To set the properties for bending

Ø  Select the required members in the Frame window.

Ø  Choose Bending from the Design menu.

Ø  Click the type of lateral restraints.

Ø  Enter the position and type of lateral restraints for both top and bottom flange.

If there are transverse stiffeners on the web or flange, click the stiffener tab and see the following window.

Ø   Enter the length of stiffener

Ø  Enter the number of stiffeners and spacing(s) etc.

Ø  Enter coefficients for unequal end moment

Ø  Click OK

Lateral restraints must always be specified at the ends of the beam and so the minimum number of lateral restraints is two. If no restraint exists at the end of a member then it should be specified as unrestrained. The initial lateral restraints applied to the member are full restraints at each end for either of the flanges being the critical flange.

The different restraints acting on the member are entered into the grid using the following codes;

F      Fully restrained

P      Partially restrained

L      Laterally Restrained

U      Unrestrained

LR    Lateral restraint with full restraint against rotation on plan

LP    Lateral restraint with partial restraint against rotation on plan

C      Continuous restraint

Fully or partially restrained sections may also be specified as lateral rotational restraints using;

FR    Fully restrained + Rotationally restrained

PR    Partial restrained + Rotationally restrained

The initial position of the loads is at the shear centre. If there are no transverse stiffeners, leave the stiffener spacing set to zero.