Results of Composite Beam Research Project Released

After what is, literally, years of work to better understand how shear studs behave in the presence of modern trapezoidal decking it’s very pleasing that information is now starting to appear in the public domain.

The start of this saga was some work carried out in Australia that suggested that the design resistances quoted in BS5950 and Eurocode 4 were unconservative.  The Australian studies also raised doubts about the level of ductility of the shear connection that is assumed and implicit in some of the beam design rules.

SCI, with substantial support from a range of sponsors, carried out three full scale beam tests at Cambridge University, then developed a push test that was based on the recommendations of Eurocode 4 but modified so that push test results better mimic the stud performances found in the beam tests.  The modified push test was then used to carry out a parametric study to understand the influence of, for example, the number and layout of the studs on their strength and ductility.  The modified push test is significantly different from the arrangement used for the Australian work, and not surprisingly so are the results.  In particular, for the arrangements tested the ductility of the shear connection was far in excess of the assumptions on which the rules in BS5950 and Eurocode 4 were based.  Over the past year or so we have been using finite element analysis to study a range of beams and see what influence increased shear connector ductility has on the minimum degree of shear connection required for beams.

So as we approach the end of this work we have revised rules for beam design appearing in an amendment to BS5950-3.1.  This was issued by BSI for public comment some time ago and the committee reviewed comments made at the end of October.  The amendment is now agreed and is probably going through the BSI process for publication as you read this article.  To provide more background information, and couch the new findings in the context of the Eurocodes, we will be publishing NCCI (non conflicting complimentary information) on http://www.steel-ncci.co.uk/

For further information, please contact:

Andy Smith
Senior Engineer
Tel: +44 (0) 1344 636530
Email: a.smith@steel-sci.com