Sonic integrity testing is a common method used to test the integrity of piles in Bangkok. An acoustic technique equipped with computer software, developed by TNo. PDL IFCO, etc. is commonly used to test the piles. This paper presents the signal characteristics and their interpretations from sonic integrity test performed on mainly bored piles varying in length, size, construction method and founded soil strata. Toe reflection of small bored piles (diameter of 0.35m to 0.60m) constructed in Bangkok subsoil can be observed for pile length of up to 20m to 24m. Beyond 35m below the ground, visibility of toe reflection is uncommon for large bored piles (diameter of 0.80m and larger). Commonly predicted defects and frequency of occurrences are tabulated. Data sets have been selected from the Data Bank of a foundations specialists\u27 organization to which the authors are associated with. Recently completed and current projects in Bangkok have been selected so that the data set could be well represented by over 8000 piles. 285 piles (3.3%) out of 8689 piles have been interpreted for poor concrete or inclusions, cracks and size reduction. Among these, cracks contribute the major portion (2.2% or 194 piles). Cracks are mainly induced by either improper excavation adjacent to the piles or trimming the pile head by ill fated ways. Small diameter piles are the most suffered by cracks. Prominent sectional variations have been indicated by the signals at depth where temporary casing ends. Intermittent variations also are common at the interface of soft clay and medium to stiff clay layers
