Links and Nibs

The left hand table defines the links in the beam. You may have a total of 7 zones i.e. 3 left zones, 1 nominal and 3 right zones with the input for each individual zone.

Link patterns are calculated automatically for the number of legs defined, however, shape codes are not important at design time, only the number of legs and whether they are in pairs or not need be considered.

10 sets 2 legs of R12 links in pairs at 200 mm longitudinal pitch on the Right hand side. (A total of 20 shape 61 links placed in pairs every 200 mm)

The drop box at the bottom of the screen allows you to define the width of the enhanced shear zone. This is then applied to all beams in the frame.

Nibs

If you have an inverted Tee or L section then it is quite common to rest slabs or outer leaf masonry on the nib.

MasterKey Concrete Beams can design this nib steel and any induced torsions in the members. Design is in accordance with BS 8110-1:1997 Cl 5.2.8

It should be noted that the vertical and torsional load induced will be transmitted into the main links thus greatly reducing their capacity. Cl 5.2.8.5

The resultant beam torsion is calculated by taking the net moment from maximum load on one side and minimum load on the other. The larger out of balance moment is then used.

Left nib %	Maximum Percentage of total shear load on the left nib (gives moment and shear on nib) Minimum Percentage of total shear load on the left nib (gives resultant beam torsion when compared with RHS max)
Left ecc mm	Eccentricity from the outer edge of the left nib to the point of load application
Right nib %	Maximum Percentage of total shear load on the right nib (gives moment and shear on nib) Minimum Percentage of total shear load on the right nib (gives resultant beam torsion when compared with LHS max)
Right ecc mm	Eccentricity from the outer edge of the right nib to the point of load application
Bars on main steel	Switch to say if the nib steel rests on the bottom steel of the main beam or is supported on side bars at a defined cover from the top surface of the nib
	Bars on main steel			Bars to top cover
Long Pitch	The longitudinal pitch of the nib reinforcement. Usually the same as the link pitch.
Top Cover	Top cover to nib steel from top face of nib. Not applicable if bars are on the main steel.
As –, L, vert U, horz U or Link	Detailing style
	-: Straight bar	L: L-bars	Vert U: Vertical U-Bars		Horiz U: Horizontal U-Bars	Link: Vertical Links
	Note the style will be modified by the program if enough anchorage is not achieved. Eg straights may become pairs of L-Bars.
Copy to All Beams	Copies the current nib settings to all downstand beams in the frame.