A comparison of the variable strut inclination and alternative stirrup design methods

摘要

South Africa’s adoption of EN 1992-1-1 Eurocode 2: Design of concrete structures – Part 1-1:rnGeneral rules and rules for buildings will introduce theVariable Strut Inclination Method (VSIM) as an alternativernanalogy for stirrup design. The unbiased stirrup contribution of the EN 1992-1-1 VSIM has been shown to yieldrnunsafe capacity predictions for relatively heavily shear-reinforced concretebeams. Conversely, the same modelrnis excessively conservative for lightly reinforced beams. This contribution compares the performance of the ENrn1992-1-1 VSIM to (1) the classical Ritter-M?rsch stirrup design analogy employed in the currently operationalrnlocal design standard SANS 10100-1The structural use of concrete, and (2) the fib Model Code 2010 ModifiedrnCompression Field Theory (MCFT)-based design analogies (Levels of Approximation I & III). TheVSIM seemsrnto be in general agreement with the other design methods, but tends to offer higher capacity predictions at stirruprnamounts in excess of 1MPa.