A quick and
reliable way of determining the load-carrying capacity of a single pile is still a problem arousing wide interest
in China. We now present our research results on such determination, which is highly useful information for design of three high-rise buildings15, 18, and 22 stories in height already constructed in 1994.Our quick and reliable determination is done in two steps:(1) The
load -carrying capacity of each of about 10% of piles is determined by dynamic testing, which is much easier and less costly than static testing. Moreover, piles after dynamic testing can still be used.(2) The load -
Carrying capacity of each of the remaining 90% of piles can be computed by using eq. (1) and soil test data.For the three Xi'an high-rise buildings, we determined the load-carrying capacties of three piles through static testing. In the last column of Table 2, we give the ratio of RKS to RKD, where RKS and RKD are load-carrying capacities determined through static testing and dynamic testing respectively. Table 2 shows that RKD is very close to RKS. In our design we of course made a conserveative estimate of RKB from our RKD, making it unnecessary to do static testing for every pile.Actually, the time consumed for static testing of three piles was much higher than time consumed on the much more numerous 10% of total piles.We saved much testing further by estimating reliably the load carrying capacities of the remaining 90% of piles. This reliable estimate was done by calculation with the help of eq. (1). In eq. (1), a and βi (i=1, 2, 3, ..., n ) are non-dimensioned coefficients for adjusting bottom reaction and frictional resistances of various layers of soil respectively, a and βs were statistically determined by using conservative estimates of PKS in the place of P in eq. (1). fsi s in eq. (1) were soil test results obtained in the laboratory for various layers of soil at different selected locations of foundation piles.