The Structural Engineer > Archive > Volume 12 (1922) > Issues > Issue 6 > What is the use of the modular ratio? Part III: Conclusion
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What is the use of the modular ratio? Part III: Conclusion

TEE BEAMS. In the current theory a grcat deal is made of elaborate formula for the resistance moments of T-beams. It would be easy for thc author to provide formultx of a similar kind devised in conformity with his particular theory, but from a practical point of view such formulze are not of general application and can be omitted. As regards T-beams, it is common knowledge to designers that it is economical as a rule to make T-beams as deep as head room will allow. The result is that the concrete of the flange of a T beam is sufficient to take all the compression at a stress which is often a good deal less than the maximum allowable. The percentage of steel employed is therefore comparatively small, such percentage being reckoned in regard to a nominal area found by multiplying the breadth of the flange by the effective depth of the beam. Therefore, in an ordinary economical design a low percentage of steel will be employed, giving as a rule a low stress even according to the ordinary theory; by the author’s method the flange will always be ample to take compression, and the part in compression will be but a small portion of the depth of the slab, that is to say, the extent of the compression will be less than the depth of the slab, so that we are able to calculate as though a T-beam were a simple rectangular beam, and the foregoing diagrams for rectangular sections apply to tee beams in practice. So far the formulae are simple, and at the same time it is contended they are more accurate than the usual. H. Kempton Dyson