Exterior negative design moment: 1 0.65 1 c c Is the ratio of flexural stiffness of the exterior columns to the flexural stiffness of the slab at a joint taken in the direction moments are being determined and is given by: K K c c s c K =sum of the flexural stiffness of the columns meeting at the joint. s K =flexural stiffness of the slab, expressed as moment per unit rotation It shall be permissible to modify these design moments by up to 10 percent, so lon g as the total design moment 0 M for the panel in the direction considered is not less than that required by:
n W l M 0 8 The negative moment section shall be designed to resist the larger of the two interior negative design moments determined for the spans framing into a common support unless an analysis is made to distribute the unbalanced moment in accordance with the stiffness of the adjoining parts. Column strip : Negative moment at an interior support: At an interior support, the column strip shall be designed to resist 75 percent of the total negative moment in the panel at that support. Negative moment at an exterior support: a) At an exterior support, the column strip shall be designed to resist the t otal negative moment in the panel at that support.
b) Where the exterior support consists of a column or a wall extending for a distance equal to or greater than three-quarters of the value of 2 l . The length of span transverse to the direction moments are being determined, the exterior negative moment shall be considered to be uniformly distributed across the length 2 l . Positive moment for each span: For each span, the column strip shall be designed to r esist 60 percent of the total positive moment in the panel. Moments in the middle strip: a) That portion of-the design moment not resisted by the column strip shall be assigned to the adjacent middle strips. 13