ABSTRACT
Flexural cracking In the case of flexural cracking, the sensitivity factors for model uncertainty show that the influence of this variable depends mainly onVθ and wlim.This influence increases as Vθ increases and as wlim decreases. The sensitivity factors indicate that model uncertainty has a small influence at a Vθ of 0.1, becoming more influential at a Vθ of 0.3 with a value of about −0.5 (wlim 0.05 mm). However, cracking uncertainty, including model factor contribution, is small in comparison to liquid load which dominates with sensitivity factors of nearly −1.0. Tension cracking Two models were set up for tension cracking, each dependent on the limiting equation for the effective depth of the concrete tension zone, hc,eff , namely 2.5(c +φ/2) or h/2, where φ is bar diameter. (i) Tension cracking – hc,eff = 2.5(c +φ/2) The influence of model uncertainty in this case of tension cracking increases by a factor of about 2.2 to about −0.7 as Vθ increases. There is a small decrease in the sensitivity factors as wlim decreases.
