Question

For initial estimate for a beam design, the width is assumed?

(a) 1/10th of span

(b) 1/30th of span

(c) 1/15th of span

(d) 1/5th of span

I had been asked this question in final exam.

My question is taken from Structural Designing and Thumb Rules in portion Valuation, Reports Technical and Design Data of Civil Engineering Drawing

Answer 1

The correct option is (b) 1/30th of span

The explanation: Design codes prescribe beam width limitations to minimise the shear lag effect on the formation of full-width plastic hinges and achieving the expected capacity. However, owing to insufficient experimental and analytical studies, empirical design formulas for the beam width limitation, with remarkably different results, have been implemented in different design codes. In this paper, parametric studies of the influence of key parameters on the behaviour of wide beam–column connections are conducted based on available test results. An effective beam-width model is analytically developed using the equivalent-frame representation, where the effects of torsion of transverse beams and flexure around the joint core are considered. The validity of the model is verified using flexural strengths of test specimens, covering a wide range of design parameters.