Reply to the Discussion by H. Jiang and B. Fu on “Experimental study of concrete masonry infills bounded by steel frames”1Appears in the Canadian Journal of Civil Engineering, 39(10): 1168–1169 [doi: 10.1139/l2012-082

Abstract

The authors appreciate comments and input provided by the discussers on the discussed paper. The additional information presented in the discussion is in most part in line with the conclusions of the paper. However, there are a couple of points that we feel are worthy of clarification. Equation [3] in the discussion for diagonal strut width calculation is misquoted. The diagonal strut width equation given in the Canadian masonry design standard CSA S304.1-04 (CSA 2004) is expressed as w ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi a 2 þ a 2 p , rather than w = ah + al as suggested in the discussion. However, the discussion following this equation is still valid. While the diagonal strut width may be considered as the source of the large difference in design stiffness between the Canadian and American Standards (MSJC 2011), it is not correct to say that it also counts for the large difference in design strength between the two standards. In the Canadian standard, the corner crushing failure is evaluated based on the compressive strength of the diagonal strut, thus the width of diagonal strut plays an important role in the strength calculation. The discussed paper showed a mean test-to-design strength ratio of 2.32 based on the Canadian standard. The authors believe that this underestimate of strength is more attributed to the fact that the compressive strength of masonry is assumed to be 0:5f 0 m in the diagonal strut compression calculation. It is not a result of diagonal width value. On the other hand, the corner crushing strength in the American standard is calibrated using test results from experimental work conducted by Flanagan and Bennett (1999) on clay tiles infilled steel frames. The equation is simple to apply but does not contain an explicit diagonal width term. The diagonal width seems to be replaced by a constant term. While it provided strength values closer to those test results presented in the discussed paper than the CSA S304 equation, it is premature to conclude that this equation is equally applicable to infills of different material and geometry. More testing data covering a wide range of variables on infills should be studied to have an overall performance assessment. References