This paper presents the comparison of dry-process bored pile capacities from static pile load test with the
allowable pile capacities calculated from the friction resistance specified by Bangkok Building Codes. The study estimates the
ultimate pile capacities using Mazurkiewicz’s method based on 42 static pile load test data of bored piles 0.50 and 0.60 m.
diameters which were constructed in central Bangkok area. The comparison indicates that the average factor of safety is 2.26 and the
minimum factor of safety is 1.7. The percentage of piles which have factor of safety below 2.0 is 17. This paper also presents a
reduction factor equation for estimating the allowable capacity of dry-process bored piles having 19-25 m. pile length.