BEARING CAPACITY FOR FOUNDATION OF FAQIR API FLYOVER, MANDI MOR, ISLAMABAD, PAKISTAN

Abstract

The aim of this study is to conduct a bearing capacity analysis and to provide the most suitable foundation design for the construction of Faqir Api Flyover, Mandi Mor, Islamabad, Pakistan using ASTM standards. The subsoil investigation program was carried out by drilling two (2) boreholes at the site's location. The method of percussion drilling was adopted and boreholes drilled up to a maximum depth of 36m.The subsoil mainly encountered was silty clay (CL-ML) and clay (CL). Disturbed samples were obtained, in situ tests were carried out and soil strength assessment analysis was performed. The Atterberg Limits (ASTM D-4318) and grain size analysis (ASTM C- 136) were performed to interpret the sub soil geotechnical behavior. Average Minimum and Maximum SPT values encountered in both bores were 13 and 50 respectively Moisture content ranges from 7.8 to 9.7 %. Allowable Bearing Capacity for Pile is measured from 0 to 30 meter against 5 different diameters i.e. 0.75m, 0.90m, 1.0m, 1.2m and 1.5m. The diameter and length of the pile found to be 1.2m and 25m to achieve the necessary allowable load. Using AASHTO LRFD equation for deep foundation, bearing capacity was calculated. On the basis of field and lab test results bearing capacity was calculated and pile foundation is recommended for the site.