Movement and Static Stresses in Dolosse
COASTAL ENGINEERING RESEARCH CENTER VICKSBURG MS
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In 1986 the seaward end of the mainstream of the outer breakwater at Crescent City, CA, was rehabilitated using 680 fiber reinforced, 42-ton dolosse. As part of the Crescent City Prototype Dolosse Study CCPDS, twenty of the 680 dolosse were instrumented to measure loading on the armor units. The instrumented units were placed near the center of the rehabilitated area. Four of the dolosse were placed in the bottom layer and the remaining 16 were positioned in the top layer. During the two years following the repair, a wealth of incident wave conditions and dolos loading and movement data were collected. Details of the CCPDS are presented in Howell, et al. in publication. Strain gages were positioned on rebar rosettes inside the instrumented dolosse in such a manner that two moments and a torque could be measured at the fluke-shank interface on one end of the dolosse, Figure 1 Howell 1988. For the CCPDS, Burcharth and Howell 1988 have proposed a concrete failure criteria for use in dolos design. The criteria compares maximum principal tensile stress to the concrete rupture strength. Melby 1989 discusses the calculation of the maximum principal tensile stress for a cross-section in the dolos shank, and limitations of this methodology, indicating that it can be used with confidence to calculate maximum principal stress in dolos armor units. Pulsating waves, impacts between units and static loads make up the three principal categories of loadings on concrete armor units Burcharth 1984. During the CCPDS, no impact loads were observed.
- Civil Engineering