Compound Sections, Cellular Beams and Slim Floor Construction

There are additional options available for compound steel sections, cellular beams and slim floor construction.

Compound Sections

An additional bottom plate can be added to the steel beam, where the thickness and width of the plate are specified. Instead of the plate width, a projection distance can be entered. The plate can be central on the beam or be offset to the left or right only.

Additional Plates

T (mm) 

Refers to the thickness of this additional bottom flange plate. 

W 

The parameter for the overall width of the plate. 

Proj (Projection)

An alternative input to width of outstand (mm), allowing the user to specify the distance the plate extends beyond the outside of the beam flange. These plates can be positioned centrally on the beam or offset specifically to the left or right. It is important to note that a member cannot be defined as a composite beam if it includes a top plate or top channel on an I-section.

Cellular Openings

A cellular beam can easily be set up.

Do (Cell Diameter) 

Refers to the diameter of the circular openings in a cellular beam, which can be entered in millimetres or specified as a ratio of the overall beam depth (e.g., 0.6).

S (Cell Spacing)

The centre-to-centre distance between the openings. It can be defined in millimetres or as a multiple of the cell diameter, up to a maximum limit of 1.95 Do​.

Cut Gap 

The additional gap allowance between the top and bottom sections of the beam when it is profile-cut along the web and welded back together to form a deeper section.

Top Dist (Top Distance) 

Defines the vertical distance from the top of the beam to the top of the circular opening. If no value is specified, the software assumes the opening is positioned centrally within the depth of the beam.

Fill openings @ m; m 

Fill cellular holes which are too close to the specified locations (m) e.g and also specify minimum clear distance from support e.g. 0.2;3;6 or specify clear distance value -0.2;3;6;-8.8. 

If a normal UB or UC is specified initially and the cells are added, the beam is considered to be profiled cut along the length of the web, moved a short distance laterally and welded back together again along the web to create a deeper cellular beam type section. The new beam depth will be dependent on the diameter of the cells and is specified in the start of the calcs.

The cells can be specified as the diameter of the opening (Do) and the spacing (S) and can be entered either in mm or as a ratio of the beam depth. For example, Do could be entered as 0.6 times the beam depth. The spacing is then entered as a multiple of the Do ratio, say 1.8. For a 356 UB, the opening diameter Do would be 0.6x356 = 215mm and the spacing S would be 1.8x215 = 385mm (rounded down from 387mm).

You can specify the distance from the top of the beam to the top of the opening. If no value is entered, it is assumed the opening is central in the depth of the beam.

The Cut Gap is the additional gap allowance between the top and bottom parts of the beam when it is being profile cut, eg, 10mm.

In some situations you may want to fill certain openings, for example those at incoming secondary beams. Enter the distance to the centre of these openings to remove them from the beam as shown above where the openings at 3m and 6m are filled.

You can also enter a value for the clear distance to the start and end of the openings by placing a minus sign in front of these distances - see below where the first 1.4 m of the beam is clear of openings and the beam beyond 8.5m is clear of openings.

Slim Floor Construction

In addition to profiled decking or precast slabs being placed on the top flange of a beam you can design slim floor construction beams where a deeper decking is placed on the bottom flange of a beam. A normal UB or UC section can be chosen from the droplist of sections and an extended plate added to the bottom flange if required, on which the deeper profile decking will sit. There are also a list of Asymmetrical SlimFloor Beams (ASBs) available from the sections droplist to accommodate the slim floor construction.