FORMULA ANGKA STABILITAS UNIT LAPIS LINDUNG PEMECAH GELOMBANG TIPE GELOMBANG TAK PECAH

Abstract

The objective of research is to evaluate variables that influence the stability number of breakwater armor units (Ns), such as height of wave, wave period, wave angle direction, layer coefficient, and porosity. While the aim of this researh is to find a new Number stability formula,that is (Hs/ΔDn or Ns ), at non breaking wave, that can be applied on all type of breakwater armor units. The research used undistorted physical model methode. Furthermore, wave data is analyzed using Zero up crossing and regression analysis using least square methode. Mat Lab software version 6.5. is used as a tool in analysis. The result of this research is stability number of breakwater armor units (Ns) for non-broken wave, that is Ns = 0,0874 o P -4,1580 d 0,0486 N-0,0278 C 7,3935(cos  )0,5385 z  -0,4640 Then the evaluation result is compared with the existing formula, such as Hudson formula and Vander Meer formula, with armor units material are stones, cube, tetrapod and dolos. It can be seen that in new formula, stability number (Ns) is the smalest number, therefore it is the most reliable or optimal, if compared with Vander Meer formula, and Hudson. The formula is applied for slope angle of the structure(cot 1,5), until slope angle of the structure (cot 3). The result also shows that the number of stability being bigger, in a row to the number of (H/L) value, and being smaller in increasing angle wave direction for slope (cot 1,5), (cot 2,5) and (cot 3).