Field Study of the Stress Development in PHC–steel Composite (PSC) Piles During Static Load Tests.

The construction and service of traditional pile foundations in port construction face some engineering problems, such as corrosion and susceptibility to cracking. In this study, an innovative PHC–steel composite (PSC) pipe pile was proposed, and static load tests were conducted on three PSC pipe piles in the field. Fibre Bragg grating (FBG) technology was also used to monitor the strain distribution during the static load tests. The results indicate that the ultimate total pile capacities of test piles PSC-1, PSC-2 and PSC-3 were 3000, 2750 and 3000 kN, respectively, and the corresponding shaft resistances were 1800, 1991, and 2196 kN, respectively. The misplaced platform of a PSC pile led to a change in the pattern of the strain and axial force reduction along the pile. Due to the effect of the misplaced platform on the lower pile—soil interaction, the shaft resistance along the PSC piles was attenuated in the soil layer containing the misplaced platform. Based on the test results, a new modified method for calculating the ultimate total pile capacity of PSC piles was proposed, and the calculation error was less than 2.1%. The average error between the ultimate total pile capacities determined by the conventional calculation method and the test results was 7.8%. For the silty clay layer, silty clay with sand layer and fine sand layer, the β values obtained with the proposed method were 14.8%, 13.6% and 16.5% more accurate than those obtained with the traditional method presented in the relevant code. [ABSTRACT FROM AUTHOR]