Web Buckling – Compression (5.13.4)

RAM Frame checks each column flange when subject to compression force according to the requirements of 5.13.4. In this section b_b (total bearing width) is based on a 45 degree dispersion from the applied load point. Where a flange is deemed to be near the top of a column this dispersion is assumed to be in one direction only and b_b = b_s + 2.5x t_f + b_bw, where b_bw = d₂/2. The capacity of the web acting as a column is calculated according to Section 6.3.3 using a column width of bb and thickness equal to that of the column web and following per 5.13.4: le/r = 2.5 x clear depth of column / thickness web column, αb = 0.5, and kf = 1.0. A web plate if it exists will be ignored when performing this check. Where required stiffeners will be used to resist this load, they will be designed according to discussion on stiffener design below.

Web Bearing Yielding – Tension and Compression (5.13.3)

A web plate, if provided, is not considered when performing this check. The dimension b_bf will only use 2.5t_f if the beam flange being considered is at the top of the column. The web plate if it exists is not considered in the calculation of the bearing capacity. If stiffeners are required they are designed in accordance with the discussion on stiffener design below.

Local Flange Bending - Tension

A local flange bending check has been performed according to the design provisions as documented in the Steel Designers Handbook. The flange capacity at the column is calculated as follows:

Rt = fyc(tfbbrc + 7tfc2)

where

fyc	=	Yield strength of the column
tfb	=	thickness flange of beam
brc	=	column web thickness plus two column fillet radius
tfc	=	thickness of the flange of the column

Where required, stiffeners are designed in accordance with the discussion below.

Web Shear (5.11.2/4/5)

RAM Frame will perform a check on the panel zone strength of a column at a beam column joint. The column web capacity will be based on the provisions of 5.11.2, 5.11.4 and 5.11.5. The capacity of the column web is calculated using the design yield strength of the column. If this capacity is not sufficient then a web plate that will be added according to the engineer specified criteria, and the panel zone capacity including the web plate will be calculated. The capacity of the web plate will only include the plate thickness over the clear depth of the column.

Stiffener Design

Where stiffeners are required for web buckling, bearing or flange bending they will be designed as full length stiffeners (complete depth of column web). The engineer has significant control over the stiffener design dimensions. The criteria by which the stiffener dimensions are calculated can be modified in the dialog displayed by invoking the Criteria - Joints command. The minimum thickness of the stiffener will be the same as the beam flange thickness. Where a stiffener is designed it will be considered as a simple column comprised of the two stiffeners and a width of column web to create a cross (+) shaped column section. The effective length of the stiffener will be considered as 0.75 x length of the stiffener, kf = 1, αb = 0.5. If stiffeners are not able to be designed the stiffener optimization criteria may need to be adjusted or a larger column size used.