Application of load transfer method for bored pile in loess area

2021 ◽  
pp. 1-19
Author(s):  
Zhijun Zhou ◽  
Zhipeng Zhang ◽  
Chaoran Chen ◽  
Fu Xu ◽  
Tianyu Xu ◽  
...  
Keyword(s):  
Load Transfer ◽  
Loess Area ◽  
Bored Pile ◽  
Transfer Method ◽  
Load Transfer Method

Installation Engineering Challenges of the World's Heaviest Topside on Steel Substructure

2021 ◽  
Author(s):  
Prasad Kunnathully Prabhakaran ◽  
Cibu Varghese ◽  
Faris Ragheb Kamal
Keyword(s):  
Weight Control ◽  
Oil And Gas ◽  
Load Transfer ◽  
Development Project ◽  
Design Stage ◽  
Gas Treatment ◽  
Field Development ◽  
Gas Processing ◽  
Transfer Method ◽  
Load Transfer Method

Abstract As part of a green field development project for ADNOC offshore, NPCC here in after called as "contractor", successfully completed installation of an oil and gas processing super complex at offshore Abu Dhabi. This super complex consisted of four large interconnected platforms of different functionalities and an accommodation platform. Associated flare structures and interconnecting bridges were also installed as part of this project. Weights of the topsides in this project were varying from 7,000MT to a ∼32,000 MT. All these topsides were installed by float-over method using contractors own cargo /launch barge fleet. Gas treatment platform topside installed as part of the above project is the world's heaviest single-module topside Installed by float-over on a fixed steel jacket. Float-over is the process of installing the topside on a preinstalled jacket by ballasting and/or by other methods of load transfer such as hydraulic jacks. This installation method is widely used for heavy topsides, due to its cost effectiveness and efficiency. By float over installation method, the topside can be installed as a single integrated unit after completion of all hookup and commissioning works onshore. This paper outlines installation engineering challenges during EPC phase for the gas treatment platform topside. Design of this topside went through phenomenal changes in terms of its size and weight during EPC phase and posed several challenges to install this unit as a single module. This paper presents the installation method, and various parameters considered during installation and also includes discussion on selection of float-over barge, importance of weight control & layout design, finalization of topside support height on barge and installation aids. This paper also presents various installation engineering analyses required during design stage. Float-over installation of the gas treatment platform was carried out by the conventional load transfer method (by ballasting) and using normal spread mooring arrangement.

Development of negative skin friction on single piles: uncoupled analysis based on nonlinear consolidation theory with finite strain and the load-transfer method

2011 ◽  
Vol 48 (6) ◽  
pp. 905-914 ◽  
Author(s):  
Hyeong-Joo Kim ◽  
Jose Leo C. Mission
Keyword(s):  
Skin Friction ◽  
Effective Stress ◽  
Finite Strain ◽  
Load Transfer ◽  
Negative Skin Friction ◽  
Consolidation Theory ◽  
Single Piles ◽  
Transfer Method ◽  
Load Transfer Method ◽  
Nonlinear Consolidation

The development of negative skin friction (NSF) on single piles is investigated based on an uncoupled method of analysis with the Mikasa (1963) generalized nonlinear consolidation theory in terms of finite strain and the nonlinear load-transfer method. Predicted results are compared with results based on the conventional linear consolidation theory with infinitesimal strains. It is found that predicted development of dragload using the conventional consolidation theory is slightly greater and conservative compared to that using the nonlinear consolidation theory based on effective stress (β method). Effective stress predictions using the conventional theory are larger due to the faster dissipation of excess pore pressures, with the assumption of constant coefficient of consolidation and permeability. However, since the relative displacements required to mobilize the ultimate skin friction are small, and piles are usually installed near the final stages of soil consolidation, the differences in the predictions for the development of dragload on piles between the two consolidation theories are overshadowed. Using the uncoupled model for pile NSF, it is therefore found that the most significant factor for the estimation of dragload and downdrag is the proper selection of the β value rather than the consolidation theory used.

scholarly journals Settlement of a Pile under Cyclic Lateral Loads in Dry Sand

Géotechnique ◽  
2021 ◽  
pp. 1-32
Author(s):  
Gang Zheng ◽  
Jibin Sun ◽  
Tianqi Zhang ◽  
Yu Diao
Keyword(s):  
Theoretical Model ◽  
Load Transfer ◽  
Lateral Loads ◽  
Cyclic Lateral Load ◽  
Practical Engineering ◽  
Pile Settlement ◽  
Dry Sand ◽  
Transfer Method ◽  
Laterally Loaded ◽  
Load Transfer Method

It is found through centrifuge model tests that the cyclic lateral load on a pile reduces the shaft friction and induces additional pile settlement. A theoretical model using the load-transfer method was proposed for the settlement prediction of cyclic laterally loaded piles in dry sand. A simple formula was established to quickly predict the pile settlement in practical engineering. The theoretical model provided a reasonable estimate of the pile settlement, while the predictions from the proposed quick prediction formula were relatively conservative. A new concept of “settlement-controlled design” was proposed to advance the methodology for the design of a pile by considering potential settlement after many cycles of lateral loads. According to the design plane derived from this study, the design-state points were suggested to be limited in the convergent zone.

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