A DESIGN AID FOR SHEAR LAG CALCULATIONS.

A semi-empirical method, termed the "3-bar method", for calculation of shear lag effects in box girders is described. Explicit solutions for different support and loading conditions are presented which enable the amplified edge stresses due to shear lag to be calculated directly. Results given by the 3-bar method are compared with those obtained from the interim design rules (idr) for box girders and there is good agreement. The ease of application of the proposed method, exemplified by the calculations in the appendix, make it suitable as an aid during initial design stages. Situations in which the effects of shear lag are important are identified. High stress amplification in heavily stiffened steel girders and at intermediate supports of continuous girders is noted.(a) (TRRL)