Rigorous assessment

The procedure is, at frequent intervals along the member, to calculate

(1) Moments

(2) Curvatures

(3) Deflections.

Here, calculations will be carried out at the mid-span position only, to illustrate this procedure, with values at other positions along the span being tabulated.

10.1.3.1 Calculation of moments

For buildings, it will normally be satisfactory to consider the deflections under A4.2(5) the quasi-permanent combination of loading, assuming this load to be of long duration.

The quasi-permanent combination of loading is given, for one variable action, by

Table 1

Therefore

Mid-span bending moment (M) = 25.6 x 72/8 = 156.8 kNm

10.1.3.2 Calculation of curvatures

In order to calculate the curvatures it is first necessary to calculate the properties of the uncracked and cracked sections and determine the moment at which cracking will occur.

10.1.3.2.1 Flexural curvature

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