Experiment Study On The Wave Impact Pressure On Elastically Braced Horizontal Deck

As the development of economy and society, the resources and space of ocean are exploiting more quickly, more and more open-piled marine structures have been constructed because of its advantage or local geological conditions. In coastal and offshore engineering, the open-piled structures will surface many different kinds of dynamic loads. Wave load has a significant impact on the safety of the open-piled structures because of the high impact peak pressure when the wave impact occurs. When the clearance is not enough because of settlement of seabed, the exceeding waves may impact on the structures and produce great pressure. The accumulation of elastically deform and little cracks can be a great threaten to structures. So, the study of wave impact pressure on structures with elastic brace is very important to theoretical research and engineering applications.The experiments are carried out in the wave flume of State Key Laboratory of Coastal and Offshore Engineering, the height of incident wave H is ranged from8cm to12cm, the period of incident wave T is ranged from1.0s to1.3s, and the relative clearance is ranged from0.0to0.4. Three models with a new elastically brace style have been manufactured to study the impact pressure on the elastic models. Experiences are carried out to study the wave impact pressure on a horizontal deck with the structures above under different new elastically braces.The properties of the time series of wave impact pressure on three models with elastic braces are investigated. The changes of the properties of the time series of pressure on the subface of three models as the variation of stiffness are investigated in detail such as the peak impact pressure, hydrodynamic pressure and the duration of impact process. As the stiffness of models’ braces decrease the peak impact pressure will become smaller and later. Besides, the figure of the impact pressure can be zigzag in the time series of pressure on model with bigger stiffness of brace. The hydrodynamic pressure of model with greater stiffness becomes smaller oscillatory. However, the hydrodynamic pressure of model with smaller stiffness will experience a process of increase firstly before the decrease process and the duration can be much longer. So, the duration of the thorough impact process will become much longer.The statistical average values of several peak values of impact pressure in time series of impact pressure of are calculated to obtain the characteristic values of peak impact pressure on all transducers. The distributions of wave impact pressures along the underside of those models as well as the changes of the distribution as the variation of stiffness and relative clearance are given. The changes of maximum impact pressure on the subface versus the stiffness, relative clearance and relative wave height have been discussed.The integral of time series of impact pressure is computed to acquire the time series of impact force on the subface of model. The characteristic values of peak impact force are acquired with the similar method used to process data of impact pressure. Then the properties of the time series of wave impact force are investigated. The changes of impact force on the subface versus the stiffness, relative clearance and relative wave height have been discussed.The impact pressure and impact force will become much smaller as the decrease of stiffness of braces. The changes of them versus relative clearance are complicated for the models with greater stiffness, but impact pressure and impact force of model with the minimum stiffness is so small that the variation versus relative clearance is not obvious. They will become greater as the increase of relative wave height, too.