Full-scale dynamic testing of Dolosse to destruction

Numerical Modelling of Forces, Stresses and Breakages of Concrete Armour Units

“…Two types of concrete armour units were studied. Dolosse units are simulated in drop tests and pendulum tests, and the numerical results are compared with physical experiments of Burcharth (1981). The dynamic stress and fracture development for both the drop test shown here and the pendulum test are in good agreement with the fracturing observed by Burcharth (1981) and what is considered physically realistic transient behavior (Guo et al, 2015).…”

Application of the finite-discrete element method to dynamic stress development in armour units and armour layers

“…the strength of units themselves, Burcharth et al (2000) and Hald & Burcharth (2000) developed two fundamentally different approaches that addressed stresses and forces calibrated from model tests. As discussed in Latham et al (2009) Burcharth (1981), Melby and Turk, (1997), Muttray et al (2005), but in spite of Burcharth's (1993) treatise on the subject, convincing the designer of a large breakwater that the chosen armour unit system has sufficient strength remains problematic. Zwamborn and Phelp (1988) by-passed stress determination and performed calibration experiments to measured the degree of cushioning (by measuring deceleration).…”

Prototype Drop Tests of Cube and Cubipod Armor Units

“…Burcharth et al (1991) Small-scale drop tests and numerical models are not very reliable when assessing CAU structural strength in prototype conditions; therefore, several prototype scale dynamic tests have been used over the past three decades to assess the structural strength of CAUs. Burcharth (1981) and Silva (1983) tested 1.5-tonne and 5.4-tonne Dolosse, and 1-tonne to 27-tonne cubic blocks, respectively. Nishigori et al (1989) tested 2 to 4-tonne Tetrapods; Turk and Melby (1998) compared drop tests of 9-tonne Core-Locs and 11-tonne Dolosse CAUs.…”

“…Lillevang et al (1976) used the 3D photoelastic stress analysis to study the breakage of Dolosse at 15 locations worldwide before the Port of Sines breakwater failure; they proposed analyzing Dolos, in a number of static loading tests to make estimations of large-size Dolos stress concentration. Dimensional analysis in addition to specifically-designed prototype drop tests and impact tests were proposed by Burcharth (1981) in an attempt to rationalize the relationship between CAU size and structural integrity; 1.5-tonne and 5.4-tonne unreinforced as well as reinforced Dolos were used in the drop tests. As a rule of thumb, Burcharth and Brejnegaard-Nielsen (1986) pointed out that the stress level in CAUs due to static and hydrodynamic loads increases linearly with CAU size, while impacts generate stress levels proportional to the squared root of the CAU size.…”