1. LRFD Bridge Design Specifications;AASHTO,2012
2. API Recommended Practice 2GEO: Geotechnical and Foundation Considerations;API,2011
3. Kim Chuan Depot (C821) – Proposed O-cell 1200 mm Area B;Bored Piling Pte. Ltd,2002
4. British Standards Institution, 1986. Code of practice for foundations. BS8004, London.
5. Brown, D.A., Turner, J.P., Castelli, R.J., 2010. Drilled Shafts: Construction Procedures and LRFD Design Methods. Publication No. FHWA-NHI-10-016/FHWA GEC No. 010, US Department of Transporation/Federal Highway Administration.