Dissimilar Pile Raft Foundation Behavior under Eccentric Vertical Load in Elastic Medium

Hu, Ke; Jiang, Kaiyu; Gou, Xiaoying; Wei, Wentao; Yan, Lei; Zhou, Tingqiang; Guo, Zhengchao; Chen, Guanwen

doi:10.3390/buildings13123040

Cited by 2 publications

(1 citation statement)

References 31 publications

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“…However, the methods mentioned above are mainly suitable for simple foundation conditions, such as a semi-infinite medium [32], or for cases in which the underlying bedrock is horizontally distributed [33]. Jiang and Hu [4,34,35] have extended the integral equation method and analyzed the behaviors of dissimilar pile rafts over inclined bedrock, but the influence of cushioning is not considered in their models. Therefore, limited research has focused on the vertical behavior of dissimilar PCFs located over inclined bedrock.…”

Section: Introductionmentioning

confidence: 99%

The Vertical Behaviors of Dissimilar Pile Composite Foundations over Inclined Bedrock

Zhou,

Tan,

Yue

et al. 2024

Buildings

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Pile composite foundations (PCFs) have been commonly applied in reinforcement engineering to adjust the vertical stiffness of foundations, due to the displacement control design criteria for foundations. PCFs that have dissimilar pile lengths, located over inclined bedrock, have shown significantly different vertical behaviors from PCFs with equal pile lengths, placed over a semi-infinite medium. However, the vertical behaviors of dissimilar PCFs over inclined bedrock cannot be predicted with the current theoretical methods, although they have been widely adopted in engineering. An analytical method is proposed in this investigation to analyze the vertical bearing characteristics of dissimilar PCFs over inclined bedrock. A pile–soil system is decomposed into fictitious piles and extended soil, and then a control equation to determine the axial force along the fictitious piles is established, stemming from the compatibility conditions between them. The vertical behaviors of dissimilar PCFs can be obtained by solving the control equation with iterative procedures, and the equation is verified by two field load tests of single piles from the Honghe bridge and a numerical case. Then, the settlement and load transfer behaviors of 3 × 1 dissimilar PCFs and their influence factors are analyzed, and the results are as follows. (1) Obvious differences can be observed concerning the axial force distribution, settlement w, and load-sharing ratio (LSR) of each pile element for different pile–soil stiffness ratios (Ep/Es). (2) The LSR of pile 1 increases from 0.074 to 0.253 for the rigid pile and from 0.062 to 0.161 for the flexible pile condition when the cushion stiffness Kc changes from 1 × 104 kN/m to 3 × 108 kN/m. The non-dimensional vertical stiffness of the foundation, N0/wdEs, increases from 10.21 to 28.95 for the rigid pile condition and increases from 8.69 to 14.44 for the flexible pile condition, when Kc increases from 1 × 104 kN/m to 4 × 105 kN/m. (3) The neutral layer depth of the pile zn, the average settlement w, and the differential settlement wd of each element head decrease with Kc, and no negative friction zone exists (zn = 0 m) for all the pile elements when Kc> 2 × 105 kN/m. (4) The N0/wdEs decreases with the distance between the pile bottom and the inclined bedrock Δ. For the rigid and flexible pile conditions, the N0/wdEs is 22.16 and 13.48 for Δ = 1 m, and 13.13 and 10.10 for Δ = 8 m. The wd reaches 16.7 mm and 4.0 mm for Δ = 1 m and Δ = 8 m, respectively. (5) The N0/wdEs increases almost linearly with an increase in l/d for the rigid pile condition, and it gradually decreases for the flexible pile condition. The developed model can improve the design and analysis of PCFs located over inclined bedrock under vertical loading.

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Section: Introductionmentioning

confidence: 99%

The Vertical Behaviors of Dissimilar Pile Composite Foundations over Inclined Bedrock

Zhou,

Tan,

Yue

et al. 2024

Buildings

Self Cite

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Database Analysis of Long-Term Settlement Behavior of Pile Foundations in Shanghai Soft Coastal Clays

Wang,

Li,

Fang

et al. 2024

Buildings

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A database of 195 field records of long-term settlement of high-rise buildings in Shanghai soft coastal clays is presented. The collected field records are divided into two categories based on pile type, i.e., bored pile and precast pile. Based on the settlement recorders collected, the long-term settlement behavior and settlement duration of the pile foundations in soft coastal clays are investigated. The statistical results show that the pile foundation in Shanghai soft coastal clays can be divided into three kinds of site conditions by considering the pile length and variation of long-term deformation behavior. Prediction models based on the power function are proposed to calculate the normalized final settlement for both bored pile and precast pile foundations. Based on the statistical results, the average normalized final settlement (settlement per floor), average settlement ratio (final settlement to the settlement when the superstructure is completed), and average settlement duration in the three site conditions for both bored pile and precast pile foundations are given. Additionally, an exponential settlement prediction model that can accurately forecast the entire settlement and post-construction settlement characteristics of buildings in Shanghai’s soft soil area is proposed. These statistical results can be referred to the preliminary foundation design works, which contribute to the quick evaluation of the possible settlement range, settlement ratio, and settlement duration of the proposed building constructed in the soft coastal clay area in Shanghai.

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Dissimilar Pile Raft Foundation Behavior under Eccentric Vertical Load in Elastic Medium

Cited by 2 publications

References 31 publications

The Vertical Behaviors of Dissimilar Pile Composite Foundations over Inclined Bedrock

The Vertical Behaviors of Dissimilar Pile Composite Foundations over Inclined Bedrock

Database Analysis of Long-Term Settlement Behavior of Pile Foundations in Shanghai Soft Coastal Clays

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