Pengaruh Pukulan Hammer Saat PemancanganDalam Mendukung Gaya Gempa Horisontal

In earthquake regions, like Indonesia, pile foundation system has additional main function to resist lateral dynamic loading induced by earthquake. Since the piles commonly fall into the category of "long pile", their first cracking moment and ultimate flexural capacity become important parameters in design. This research was conducted to prove experimentally the effects of driving hammer during construction phase on the degradation of the first cracking moment and ultimate flexural capacity of the non-prestressed precast , concrete piles. Twelve non-prestressed precast concrete piles, that experienced various number of real drop hammer blows (0 upto 512 blows), were taken from site and tested in the laboratory. The piles had triangle cross sectional shape, three q5 19 nun steel reinforcing bars, and made of concrete with f MPa. The piles were devided into 4 groups: K1 (control group) for piles that had not been experiencing any blows\u27 K2 for thOse experiencing 142-165 blows, K3 for 240345 blows, and K4 for 512 blows. FourLpoint-loading procedure was adopted for testing the piles flexurally, and their load-deflection curve responses were observed and recorded. The loads were applied ,sequently with the load increment of 10 kN upto the\u27collapse. The results showed that compared relatively to K1: (a): K2, K3and K4 experiencing 22.6%, 41.9%, and 63.88% degradation of the first cracking moments, respectively(b) the degradation of the first cracking moment tends to increase with the increase of the number of hammer blows, however (c) the degradation of the flexural stiffness, yield moment, ultimate moment, and displacement ductility of the non-prestressed precast concrete piles did not seem to be significant. The results suggested that driving precast piles using drop hammer did not alter the flexural properties of the driven piles significantly