PENYELIDIKAN GEOTEKNIK UNTUK MENENTUKAN PONDASI JEMBATAN RAILWAY UNDERPASS WONOREJO KABUPATEN KARANGANYAR PADA STA 12 PROYEK JALAN TOL SOLO - NGAWI

Abstract

The enormously infrastructures development is a one of key factor of national economics growth. The published of 2002 president decree about continuing infrastructure project including toll highway, makes the toll highway development has started again as well as the national economics improvements. One of the example is Solo-Ngawi toll highway. In development of toll highway there was be found toll crossing structures, which one of them is underpass railway bridge that is a structure building connecting to the existing road which crossed by toll highway where those road positioned under it. Development of Railway Underpass Bridge Wonorejo in Karanganyar Regency is a kind of crossing at toll highway project solo-ngawi, in the planning of bridge development foundation was conducted by geotechnical investigation such as core boring, dutch cone penetration, pit test and hand boring and also soil mechanics test laboratory. The objective of those investigations is to get some data about physical and mechanical characteristics of the soil and the purpose is to obtain some parameters in foundation planning calculation. The research methods which used are descriptive method, survey method and analysis methods. The analysis method which used to determine the kind of foundation is soil mechanics laboratory analysis and fondation calculation analysis by using field investigation and soil mechanics laboratory such as unit weight of soil (), cohession (c), and angle of shearing resistance (Φ). Based on calculation soil bearing capacity analysis, footing foundation 1 m x 1 m in the depth of 3 m, has soil bearing capacity as 113,3ton/m2, pier foundation 80 cm in diameter at depth 3 m, has soil bearing capacity as 104,383 ton and piled foundation 40 cm in diameter at depth 5,5 m has soil bearing capacity as 267,34 ton. Based on 63rd dutch cone penetration data shown that the hard soil layer positioned at depth 2,70 m, by value of conus resistance > 100 kg/cm2. Based on the analysis method, can be determined that there is no need deep foundation to withhold the 100 ton bridge burden, so the kind of foundation which more effective and efficient to be used are footing foundation 1 m x 1 m at depth 3 m.