Seite - 688 - in Book of Full Papers - Symposium Hydro Engineering

COMMISSION INTERNATIONALE DES GRANDS BARRAGES ------- VINGT-SIXIEME CONGRES DES GRANDS BARRAGES Autriche, juillet 2018 ------- EXPERIMENTAL INVESTIGATION ON STEPPED SPILLWAY PERFORMANCE OF UPPER CISOKAN DAM IN INDONESIA 1James ZULFAN & 1,2Nuryanto S. SLAMET 1Researcher, MINISTRY OF PUBLIC WORKS AND HOUSING, INDONESIA 2Phd Candidate, THE UNIVERSITY OF QUEENSLAND, AUSTRALIA 1. INTRODUCTION Nowadays, the stepped spillway design has been widely used in many countries in the world due to the rapid development of RCC (Roller Compacted Concrete) dam which gives both structural and economical benefits. Although this concept existed for 3500 years (Chanson, 2010) the development is still growing from time to time. Peyras et al. (1992) mentioned that this type of spillway would gain economic mean approximately 20% compared to other types, the reason is because the ease of construction and design simplicity. Many studies has been done by several researcher specifically on this type of dam such as Rajaratnam (1990), Rice and Kadavy (1996), Yasuda and Ohtsu (1999), Chanson and Toombes (2002), Boes and Hager (2003), Gonzalez (2005), Takahashi et al. (2006), Hunt and Kadavy (2007, 2008), and Felder and Chanson (2008). Boes and Hager (2003) found that one of the advantages of this design is cheaper construction cost due to the decrease of stilling basin size. However, this concept has not been fully implemented in Indonesia. There are some weir structures that adopt this concept by using stepped shape on its spillway, however, it has not been implemented on dam construction. Currently, the stepped spillway concept will be applied in Upper Cisokan Dam in Indonesia. The Upper Cisokan Dam is located at West Java Province on Cisokan River. Nevertheless, since this type of spillway is still new and has not been designed in Indonesia before, a physical model test is needed to be done to see the behaviour of the dam. We also found that research to study the pressure on dam spillway using pressure tranducer at hydraulic laboratory is still rare. The 688