Transverse Flexure in Continuous Footings

The required flexural capacity for a section parallel to the footing's major axis is calculated by defining a width effective to each column or wall as:

For columns away from the footing ends: w/2 + 3d/4 on either side of the column centerline

For columns at the ends of the footing: w/2 + c

The effective width is taken as the sum of the minimum values of the equations above for either side of the column.

where

w	=	Column width parallel to footing local major direction
c	=	Distance from column face to footing end
d	=	Depth of footing from top surface to centerline of flexural reinforcement parallel to the footing minor axis direction.

Continuous Footing Segment Locations for Transverse Flexure Reinforcement

The width effective to each column and/or wall along the footing then serves as the basis for the sections for which transverse flexure is evaluated along the footing. This is reflected in the RAM Foundation continuous footing view/update dialogue as segment numbers (see Figure below).

Transverse reinforcement segments as viewed in RAM Foundation view/update dialogue.

The soil stress acting on each segment is recovered from the finite element analysis for each load combination. The required moment capacity for a transverse segment is calculated as:

Overhand Length: $L^{'} = w_{1} - \frac{b_{c}}{2} & w_{2} - \frac{b_{c}}{2}$
Total Force on Section: $q_{ult} = \frac{TotalSpringForce}{B \times SegmentLength}$
Moment Capacity: $M_{u} = \frac{q_{ult {(L^{'})}^{2}}}{2}$

The process is repeated for all columns and all the regions between columns.