Author(s): G. Muller; P. Hull; W. Allsop; T. Bruce; M. Cooker; L. Franco
Abstract: Up to the middle of this century many coastal structures were built from blockwork, using either natural stone blocks or concrete blocks. Those blockwork structures subjected to breaking wave impacts often show a particular damage type, whereby individual blocks are shifted out of their position and moved into the sea. Engineers have suspected for a long time that wave impact pressures can travel into the water filled cracks and joints of such structures, building up pressures inside of the structure and thus destroying the structure from within. In order to verify the damage mechanism, and to investigate the characteristics of impact induced pressure pulses, model tests on the propagation of wave impact pressures into water filled cracks were conducted. It was found that impact generated pressure pulses can enter water filled cracks and that they exhibit wave-like characteristics such as finite propagation speed, reflection, superposition and attenuation. Changes in cross section were found not to affect pressure pulse magnitude or duration. The possibility of wave impact pressures to damage or destroy cracked or fissured structures from within the structure could thus be verified.