Bursting and Spalling in Pretensioned U-Beams - Ferguson ...

Figure 2.1 Severe cracking in a pretensioned concrete beam end region(Marshall & Mattock, 1962)The fundamentals of some analytical methods are presented in this chapter fortheir historical influence; however, the focus of this literature review is on experimentalresearch. Despite million-fold advances in computational power since the days of handcalculations, modern-day methods are not significantly more accurate when it comes topredicting what matters most to bridge engineers: the location and extent of cracking.The strength-side approach arose from the high degree of uncertainty apparenteven in state-of-the-art analyses. Gergely, Sozen and Siess (1963) saw the debatebetween approaches based upon “what starts a crack” (stress side) or “what stops a crack”(strength side) as trivial: only the latter approach could be translated into intelligibledesign guidance. The prevailing winds in the early 1960s blew toward “a morepragmatical treatment” of the problem:It has now been established that instead of treating the problem as a stressconcentration problem in a homogeneous elastic body, it should be handled as anequilibrium problem of free bodies produced by the formation of cracks. Thewidth and length of cracks became to be of concern. Therefore, the analytical andexperimental methods are equally important. The question is not of distribution,7