Analisis Modifikasi Desain Pondasi Tower AA6+0 Kelas 3 Tipe Normal Menjadi AA6+6 Kelas 6 Tipe Borepile (Studi Kasusu: Area Lokasi T.05 PT Semen Grobogan SUTT 150 kV Ungaran - Mranggen - Purwodadi)

Abstract

The foundation of tower T.05 is one of the towers located in the Section 2 (Tanggung – Purwodadi) transmission line SUTT 150 kV Ungaran – Mranggen – Purwodadi in the PT Semen Grobogan location area which was constrained due to conditions in the field, so modifications and design changes were made foundation class from AA6+0 class 3 (normal) to AA6+6 class 6 (borepile).The purpose of this study was to determine the results of the analysis of the dimensions of the borepile foundation against the compressive and lifting forces compared to the normal foundation (footplat), the results of the calculation of the lateral forces and the safety of the foundation stability against the shear force and to know the results of the calculation of the effective reinforcement of the borepile foundation. This study uses descriptive quantitative methods.The dimensions of the tower foundation T.05 AA6+6 class 6 borepile with a diameter of 40 cm at a depth of 8 meters safe against compress forces obtained the carrying capacity of the pile group permit PGtk = 1,461,080 KN > Pu = 1,053,643 KN and safe against forces uplift can be obtained carrying capacity of axial tensile permit Ta=454.98 KN > T = 451.594 KN. Compared to the dimensions of the foundation class 3 it cannot be used due to limited land. The results of the calculation of the lateral force obtained the ultimate lateral force (Hu) = 26.14 KN and of the stability of the foundation stability T.05 AA6+6 safe against shear forces. Calculation of effective reinforcement on the foundation T.05 AA+6 borepile used 8 D 16 mm and spiral used Ø10-200 mm. Reinforcement pad foundation used diameter 30 D 16-200 mm. Reinforcement for the pedestal column used 12 D 16 mm and hoop for the pedestal column 12 10 - 250 mm.