Reuse of existing piles

A review of various non disruptive methods for estimating length in existing pile foundations is in this chapter. Durability assessment and load carrying capacity assessment of the existing pile foundation must be performed as discussed. The first illustrative example is on the reuse of existing 500 mm dia. 30 m long reinforced concrete piles embedded in soft clay, clayey silt, mucky clay and silty clay and 74 new displacement concrete piles with a length and dia. of 30 m and 400 mm. The raft foundation with six existing 8 m dia. caissons of the second illustrative example is sitting on predominately weathered sandstone, siltstone and mudstone with a few on hard residual soil of sandstone, siltstone and mudstone with NSPT>100. An additional 232 number of 1.2 to 2.5m dia. bored piles are installed to further enhance the raft foundation.