These equations are valid where x' < h. When x' > h, rather simpler equations can be derived.

The location of the reinforcement is shown in Figure 5.5.

Figure 5.5 Location of reinforcement The stress in a bar is given by f _/200000 x 0.0035 \

700z where z

yd cosQ

db = depth from top face of section to bar considered. This will be d' for top bars and h - d' for bottom bars.

The force in each bar is M and the moments are obtained by multiplying the forces by the distance of the bars from the centroid of the concrete section. Dimensions to the right or upwards are taken as positive.

The total moments and forces carried by the section are the sum of the steel and concrete contributions.

The correct values of x and 6 have to be found by iteration. 5.3.4 Initial data

0 0

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