EXPERIMENTING ON THE EFFECTIVENESS OF RIP RAP ROCKS AS AN ENERGY DISSIPATING STRUCTURE

The design of the energy dissipator probably includes more options than any other phase of a spillway design. The selection of the type and design details of the dissipater is largely dependant upon the pertinent characteristics of the site, the magnitude of energy to be dissipated and to a lesser use. Good judgment is imperative to assure that all requirements of the particular project are met. Regardless of the type of dissipater selected, any spillway energy dissipator must operate safely at high discharges for extended periods of time. This study presents a detailed explanation on the various designs of rip rap rock energy dissipators and their applications on a spillway. The importance of energy dissipator on a spillway is to protect structures downstream from a spillway. The purpose of energy dissipator is to dissipate energy from the flow of water so that is not strong enough to harm or damage downstream structures of a dam. Thus, the objectives of this study are as follows, to design several designs of rip rap rocks energy dissipating structures, to perform experiments on the model using various flows and to compare the performance of the designed rip rap models. Three designs have been selected for modeling and presented in this report. The three models were constructed with reference to the rip rap design located on the spillway on the Kenyir Dam in Terengganu, baffled blocks basin designs, baffled apron drop design and gabion designs. These models will then be experimented in a flume available in the laboratory using various flows to determine the most effective energy dissipator. Upon experimentation, it is understood that the model that was built with reference to the design of the energy dissipator located at the Kenyir Dam, was found to be the most effective energy dissipator for it was able to dissipate the most amount of energy compared to the other models that were constructed. Furthermore, it had a larger surface roughness area compared to the other models as well