Analysis of an O-Cell Pile Test in Jinan with FEM

2012 ◽  
Vol 170-173 ◽  
pp. 33-36
Author(s):  
Ying Jie Zheng ◽  
Xue Dai ◽  
Lian Xiang Li

In order to promote the experience of applying O-cell pile test to determine the behaviors of integral pile in Jinan, a case of O-cell pile test in Jinan was analyzed with proposed approach. The pile-soil system was simulated with FEM. The resistance parameters of piles, the load-displacement curves and the ultimate bearing capacity of integral pile were determined. Comparing with results obtained from load transfer method, it is found that the p-s curve of integral pile obtained from load transfer method is conservative.

2011 ◽  
Vol 368-373 ◽  
pp. 1566-1571
Author(s):  
Guang Qin Cui ◽  
Zeng Rong Liu ◽  
Chen Guang Ma

Basic transfer differential equation and transferring model of load transfer method were given at first, and the pile-soil loading state was divided into five stages according to the increasing pile-head loading process. Next, based on the overall equilibrium of pile and boundary conditions, analytical stiffness expressions of single pile relating to these transferring model parameters were derived in stages. And then, the field static load test result, Q-s curve, was also divided into five corresponding stages and subsection fitting was suggested to be made for each stage. Finally, each model parameter was determined one by one in stages according to the corresponding relations between the measured Q-s curve and the proposed analytical solutions. This pile-soil parameters determination method would enhance the application value of the measured Q-s curve in some extent, and it would provide a theoretical basis for further study on mechanical properties of pile-soil system.


2021 ◽  
Author(s):  
Bin Lei ◽  
Wengui Li ◽  
Zhuo Tang ◽  
Fuzhi Yang

The application of recycled compound concrete made of demolished concrete lumps (DCLs) and fresh normal concrete in pier foundation can effectively improve the utilization efficiency of construction waste resources. In this study, two prefabricated pier foundations based on recycled compound concrete (dimension of Ø800 × 2500 mm and Ø1000 × 2500 mm) and two cast-in-place pier foundations based on ordinary concrete (dimension of Ø800 × 2500 mm and Ø1000 × 2500 mm) were tested. Special attention was devoted to the load-settlement curve characteristics of the precast pier foundation of compound concrete, the load transfer law of the pier-soil system, the soil pressure distribution at the bottom of the pier, and the failure mode. The results showed that the Q-S curve of precast concrete pier foundation made of recycled compound concrete is slow deformation at loading, which is consistent with that of cast-in-place concrete pier foundation. The load transfer theory of pier-soil system is established, and its accuracy is verified by experimental analysis. The precast foundation of recycled compound concrete is the same as the cast-in-place foundation of ordinary concrete. The failure form of prefabricated pier foundation made of recycled compound concrete was a local shear failure, while the failure form of ordinary concrete cast-in-place pier foundation was piercing-type shear failure. The feasibility of relevant theoretical methods for calculating the vertical ultimate bearing capacity is examined.


2021 ◽  
Author(s):  
Prasad Kunnathully Prabhakaran ◽  
Cibu Varghese ◽  
Faris Ragheb Kamal

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.


2013 ◽  
Vol 639-640 ◽  
pp. 688-693
Author(s):  
Jin Yi ◽  
Guo Jing He ◽  
Si Si Liu ◽  
Zhi Yong Li ◽  
Zu En Zheng

This paper introduced construction method for deep pile of Zishui bridge through karst region and the checking results of the pile bearing capacity. Firstly, main structure of Zishui bridge was simply introduced. Secondly, according to the special geological conditions, construction methods for bored piles in water and drilling platform were described. The discussion focused on the problem of boring and grouting in karst foundation and their solutions. Finally, to ensure that the pile capacity can meet the design requirements, load transfer method was used on the part of pile foundation to calculate the bearing capacity. Results showed that pile bearing capacity meet the requirements, and the feasibility and correctness of construction method of Zishui bridge was also verified,which provides references for the design and construction of the same civil engineering.


2011 ◽  
Vol 3 (2) ◽  
pp. 64-71 ◽  
Author(s):  
Kęstutis Kelevišius ◽  
Jonas Amšiejus ◽  
Šarūnas Skuodis

In most cases, the bearing capacity of the pile under natural conditions can be determined by applying static and dynamic pile tests as well as the numerical modelling of a dynamic test. The integrated business problem is employed for calculating vertical displacements. This integral is calculated using the summing method. In the majority of cases, real pile strength capacity can be investigated referring to the adapted means of testing applying the mathematical model that can calculate static or dynamic investigations. The idealized scheme of a pile test is presented including a hammering system and soil properties. Moreover, information on the analysis and work of the scheme is disclosed. The article also describes pile hammering models and the equation for Smith method improved by Edwards, Holloway, Briaud and Trucker, Rieke and Crowser, ”GRL“, including the advantages and disadvantages of the introduced method. Smith realized the mathematical analysis of wave propagation supported by a real hammer-pile-soil scheme by discretic elements interaction. Basing on this for classical one dimensional method of wave propagation (that is programmed in computer program MW87) the code of the computer program was changed by authors of this article. When using a computer program, an algorithm for an integral equation was created. The introduced algorithm was made for counting experimental displacement the growth of which along the pile was analyzed. All obtained results were compared with the engineering method indicating that diff erence in results made less than 2%. Using computer program MW87, a diff erent distribution of shaft friction along the pile was studied when the total shaft friction in all cases was constant, because, the results of numerical modelling disclosed that the shaft friction of the pile in one diameter above the pile’s toe was larger than that in the middle or at the top. The hammer-pile-soil system was analyzed with reference to the impact of the returning wave at the top of the pile. Wave propagation in the pile is vertical: the first wave moves from the top to the bottom of the pile. When the bottom is reached, impact wave returns to the top of the pile. All information about the pile of the returning wave is useful as then we can analyze the integrity and bearing capacity of the pile. All this information received from the returning wave is integrated and later shown in the scheme where we can see all steps of performed operations. This article investigates soil deformations and these deformations in soil influence for a hammering pile. A pile of 0,8 m in diameter and 3 m in height, which is in sand, is an object of investigation in this article. For calculation purposes, the pile is divided into 20 segments. Changes in velocities and displacements of pile segments during analysis are graphically shown. Aft er calculating tests on pile dynamics considering diff erent masses of hammers, falling heights of hammers, contribution of shaft friction and static resistances of the piles, a nomograme for determining static resistance of the pile was made. The article explains how the use of the nomograme determines static resistance of the pile and what data on conducting a pile test are needed.


2011 ◽  
Vol 48 (6) ◽  
pp. 905-914 ◽  
Author(s):  
Hyeong-Joo Kim ◽  
Jose Leo C. Mission

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.


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