Overview of Some EPRI Research for Transmission Line Structure Foundations

Kulhawy, Fred H.; Trautmann, Charles H.; Hirany, Anwar

doi:10.1061/40642(253)24

Cited by 6 publications

(3 citation statements)

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“…Owing to the absence of experimental data for θ int , the approach of Kulhawy et al . [35] was used, where the friction coefficient ranges from 0.5 to 0.7 of ϕ p . Because the tested pipe is new and relatively smooth, the lower bound coefficient of 0.5 (i.e.…”

Section: Finite-element Modelmentioning

confidence: 99%

Numerical techniques for design calculations of longitudinal bending in buried steel pipes subjected to lateral Earth movements

2019

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This paper presents simplified finite-element analysis procedures based on geometrical nonlinearity and ductile Mohr–Coulomb–Davis plasticity for analysis of bending behaviour of steel pipes subjected to lateral soil loading. A simple, and easy to implement, user-defined subroutine to represent soil stiffness using the Janbu model is also presented and discussed. The development of a three-dimensional (3D) finite-element model is presented, and its evaluation against experimental measurements is discussed. Data are presented for different burial depths of the pipe, including soil loading on the pipe as well as 3D responses, longitudinal bending deflections and pressure distribution along the pipe. It was shown that numerical analyses which include soil modulus dependency on confining pressure lead to effective 3D calculations of pulling forces, bending moments along the pipeline and flexural deformations, based on measured soil parameters. The 3D analysis model requires the use of lower order (linear displacement) elements, which overestimated peak mobilized load. However, those 3D calculations effectively provided the progress of both the load–deflection and longitudinal bending response of the steel pipe at embedment ratios up to 5 where most energy pipelines are buried.

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Section: Finite-element Modelmentioning

confidence: 99%

Numerical techniques for design calculations of longitudinal bending in buried steel pipes subjected to lateral Earth movements

2019

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“…Additional modifiers that include foundation shape (s), depth (d), and rigidity (r) were introduced. Considering these modifiers to circular shafts, the general form of the bearing capacity equation for drained compression tip capacity is given by [2]:…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Tip Capacity Analysis Model for Drilled Shafts in Gravelly Soils

Chen

Marcos

Chu

et al. 2013

AMM

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This paper examines an analysis model for predicting the tip capacity of drilled shaft foundations under gravelly soils. Forty one static compression load test data are utilized for this purpose. Comparison of predicted and measured results demonstrates that the prediction model greatly overestimates the tip capacity of drilled shafts. Further assessment on the model reveals a greater variation in three coefficients; the effective overburden pressure ( ), the overburden bearing capacity factor (Nq); and the bearing capacity modifier for soil rigidity (ζqr). These factors are modified from the back-analysis of the drilled shaft load test results. Varying effective shaft depths are considered for the back-calculation to explore their effects on capacity behavior. Based on the analyses, the recommended effective shaft depth for the evaluation of effective overburden pressure is limited to 15B (B=shaft diameter). The Nq and ζqr are enhanced while maintaining their basic relationship with the soil effective friction angle, in which the Nq increases and ζqr decreases as increases. Specific design recommendations for the tip bearing capacity analysis of drilled shafts in gravelly soils are given for engineering practice.

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“…The first trial of micropiles was made in 2003 in 500kV Jiaxing-Wangdian transmission line engineering in Zhejiang Province. Generally, the electric power transmission foundation may be subjected to vertical compression or tension load in the vertical direction directions [11]. Frictional resistance between the surface of the pile and soil is considered as the possible mechanism for vertical load bearing capacity.…”

Section: Introductionmentioning

confidence: 99%

Behavior of Micropiles in Soft Soil under Vertical Loading

Qian

Xian

2011

AMR

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The behavior of micropiles in soft clay, under vertical compression and tension loading, was examined by field tests at a site in Shanghai. The soil profile consists of topsoil, silty clay, sandy silt, muddy clay, and clay soil. Two compression and three tension loading tests were conducted on five single micropiles. The piles were instrumented with vibrating wire force sensors, and they were monitored during the process of loading to investigate the mechanisms of load transfer. Both the ultimate vertical load capacity and the deflection at applied loads were examined. The results indicate that the pile load–displacement response under vertical compression or tension loadings was nonlinear. Both the compression and the tension load carrying capacity basically increased with a linear trend. But, the ultimate load capacities under tension were about 50-60% of those under compression. Tip resistance was about 10-15% of the applied compression load, not existing in the micropiles under tension. The average skin friction for micropiles under compression loading was about 50% higher than that for piles under tension loading.

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Overview of Some EPRI Research for Transmission Line Structure Foundations

Cited by 6 publications

References 0 publications

Numerical techniques for design calculations of longitudinal bending in buried steel pipes subjected to lateral Earth movements

Numerical techniques for design calculations of longitudinal bending in buried steel pipes subjected to lateral Earth movements

Evaluation of Tip Capacity Analysis Model for Drilled Shafts in Gravelly Soils

Behavior of Micropiles in Soft Soil under Vertical Loading

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