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In this study, the effect of pile surface roughness on the lateral load–carrying behavior of piles embedded in sand was investigated. Centrifuge tests were conducted on various model piles with different degrees of surface roughness. The effects of the pile surface roughness, given by the normalized roughness, Rn , on the lateral-load capacity and lateral displacement were analyzed. From the centrifuge tests, it was observed that the lateral-loading capacity markedly increased with the pile surface roughness. The effect was most significant within low degrees of surface roughness up to Rn of 0.024. Surface roughness parameters for the p-y method were proposed as a function of Rn , which could explain the effect of the pile surface roughness on calculated lateral load–displacement curves. Finite element analyses were performed to assess and compare the experimentally and numerically determined effects of the pile surface roughness. The numerical simulation of laterally loaded piles does not fully reproduce the experimental effect of surface roughness on the lateral-load response, which needs to be properly considered in the analysis. [ABSTRACT FROM AUTHOR]

As a combined foundation, micropiled rafts under compressive loads show the load-sharing behavior between raft and micropiles. The load carrying and sharing behaviors of micropiled rafts installed with inclined condition would become further complicated as a result of the coupled influences of group and inclined configurations. In this study, the 3D finite element analyses were performed to investigate the load carrying and sharing behaviors of inclined micropiled rafts. Changes in foundation configurations, including micropile inclination angle and spacing, were considered in the analyses. The load carrying capacity of micropiled rafts varied with the inclination angle of micropiles and the proportion of load carried by inclined micropiles was larger than for vertically installed condition. The values of the load sharing ratio α p for the inclined condition were obtained and analyzed. The normalized load-sharing model for inclined micropiled rafts was proposed with the modified load capacity interaction factor and design equations as a function of micropile configuration and inclination angle. Case studies were selected from the literature and adopted to compare with the calculated results using the proposed method. The calculated results were in reasonable agreement with measured load sharing ratios. [ABSTRACT FROM AUTHOR]

In this study, a CPT-based dynamic p-y analysis method was proposed for the seismic design of piles in sand. The proposed method is aimed at establishing an effective seismic design method for monopiles by directly incorporating in-situ test results into the design process. For this purpose, the continuous and in-situ soil profiling capability of CPT is utilized, which can further enhance the seismic design of monopiles by minimizing uncertainties involved in soil characterization process based on sampling and lab testing procedure. The proposed method was established based on the pseudo-static analysis with the dynamic p-y curve and equivalent static load. The CPT-based p-y curve was formulated as a function of the cone resistance considering damping effect. The load responses of dynamic load test were compared with results obtained from the proposed method and the finite element analysis. It was shown that the proposed CPT-based dynamic p-y method was effective for the seismic design of monopiles. • Dynamic p-y analysis method based on CPT results for offshore monopiles was proposed. • The proposed method can utilize continuous soil profile using CPT. • Dynamic p-y curves were established in terms of cone resistance. • CPT-based method was verified by comparing results of 3D numerical analysis and a centrifuge test. [ABSTRACT FROM AUTHOR]

In this study, the uplift load-carrying behavior of inclined micropiles (MP) embedded in various soil-rock layer conditions was investigated. For this purpose, a series of model load tests and finite element analyses were performed. The focus was given on the effects of MP inclination angle (θ) and rock-embedded ratio (Z r /L). For MPs in rock, the uplift load capacity (Q u,θ) was highest when vertically installed and decreased with increasing θ. The Q u,θ of MPs embedded in soil-rock mixed layers increased with Z r /L and decreased with increasing θ. Marked increases in Q u,θ were observed for Z r /L larger than 0.6 for all θs. As MPs inclination increased, the load-carrying mechanism shifted from the frictional resistance towards the passive resistance. The MPs inclined configuration caused less mobilization of the frictional resistance within the rock-embedded zone while producing the passive resistance within the upper soil zone. This explained the reductions in Q u,θ with increasing θ for MPs with the rock-embedded condition. [ABSTRACT FROM AUTHOR]