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By Matthew Janes

Statnamic load testing is becoming widely accepted as a method to quickly and economically determine the load-deflection behaviour and ultimate static resistance of high capacity deep foundations. Strain instrumented large diameter bored shafts were tested at four locations for the federal and state Departments of Transportation in the United States. Tests were conducted vertically (to 30 MN) and laterally on the shafts and, in some cases, testing was completed over water. Instrumented shaft test results provided shaft load distribution with depth and shaft shear transfer stress throughout the soil stratum. Shaft end bearing and ultimate end bearing stress values were provided. On two projects, Osterberg load cells provided comparative static data for skin friction and end bearing. Correlations between Statnamic derived static load-displacement results and Osterberg load-deflection results are very good. Statnamic lateral load test results were correlated with static lateral results in addition to providing useful dynamic response and damping data.

Jan 1, 1996

By Boleslaw A. Klosinski

Drilling of a pier hole is accompanied with stress releasing in the surrounding soil and often with loosening of soil at the pier base. In effect the drilled piers are more deformable than driven piles of comparable dimension. The bearing performance of a pier may be considerably improved by properly executed base grouting. Various techniques of base grouting are used; many of them were described by Bruce (1986). The grouting devices are often placed within the pier. Alternatively the soil at or under the base is treated by cement or chemical grout. Preloading of the base subsoil by use of a special grouting cell is considered as the most effective way. Treatment of the ground below pier base with cement or chemical grout may be also useful. It may be performed immediately after the pier construction or during service, as a measure for increasing the pier capacity.

Jan 1, 1995

By S. L. Karunakaran

Selection of an appropriate foundation system requires great skill and ingenuity on the part of the designer. Certain guidelines for choosing between a pile and raft foundation are presented. A number of methods are available for estimating the capacity of piles, giving a wide range of values for the theoretical load carrying capacity. A few aspects to be taken into account while arriving at an appropriate theoretical capacity are discussed. The effect of fluctuation of water table level on the pile capacity and method of accounting for this factor on the pile capacity obtained through initial load test are also discussed. A case study presents a comparison between the estimated values of capacity of piles and the values obtained through the initial load test.

Jan 1, 1996

By Gang Guo, Zhong Liu, Yi Zhang, Jingchun Lu

"Abstract Application of soil displacement screw pile (known as SDS pile) has been experiencing accelerated growth in Chinese deep foundation industry because of its technical advantages, environmental benefits, and cost effective as well. As bored displacement piling, SDS piles are able to perform better than non-displacement piling such as CFA plies due to changing the stress state in the soil around SDS piles during the installation. Therefore the design methods between the conventional pile type and SDS pile type have some differences. Based on the methodology research, current Chinese piling rigs, displacement augers and piling projects are introduced, and the current design approaches for SDS piles in China are also described. Moreover, the design results are verified by using full scale load tests, and a part of the research results of SDS piling system acquired in China are presented.IntroductionThe Continuous Flight Auger Pile, also known as the CFA pile, has occupied about 22% in the pile market all over the world (Van Impe, 2004; Bottiau, 2006). The CFA piles are usually used for large diameter (600mm~1200mm) pile foundations and deep excavation projects. Whereas the small size CFA piles (400mm~500mm) are mainly applied for composite foundations in China. In the past 10 years, the new technology of soil displacement screw piling has been applied worldwide (Prezzi et al., 2005). And it is also extensively used for high-rise buildings, industrial plants and railway projects in China (shown in Figure 1)."

Jan 1, 2014

By S. S. Gajin

The paper deals with parametric vibrations of an axially loaded pile. The dynamic model is derived by means of Hamilton's principle and reduced to a partial differen­tial equation with variable coefficients and corresponding initial boundary conditions, taking into account the influence of the axial force. By means of Galerkin's method, the partial equation is further reduced to a Matheu-Hill's matrix partial differential equation of the second order. Since the problem of the dynamic stabili­ty has been expressed only for standing piles, the paper analyses in detail two stan­ding piles, one which is restreined, whereas the other is hinged at the toe. In both cases it is assumed that head horisontal displacement is prevented. Using Ruunge-Kutt's method, a computer analysis in the time domain is given for the characteristic parameters and possible boundary conditions. The paper analyses the stationariness of the process, as well as the dependance of the critical excitation frequency upon the pile parameters. The results have been illustrated by respective diagrams.

Jan 1, 1989

By R. H. Wright

This paper describes the design philosophy and methods employed in constructing the foundation elements for the Little Britain Project in the City of London. The Contract is a design and construct package for the foundations of a 3-storey basement which will be built using "top-down" construction techniques and is to be carried out by Fairclough Piling and Marine on behalf of Wimgrove Nominees. The Project includes 8000 sq.m. of diaphragm wall and barrettes 139 No. large diameter piles ranging from 900mm to 3000mm in diameter and up to 45m deep, and 9 No. cruciform barrettes for the heaviest column loads. Major factors influencing the design of these foundations include differential settlement, heave analysis and a fast track construction approach. Little Britain will provide 43000 sq.m. of space in two linked buildings which will bridge a new road joining London Wall to Newgate Street. The foundation contract is well advanced and the building is due for completion in the Summer of 1990.

Jan 1, 1989

By B. Sivarama Sarma, Biswabikash Rout

"Seepage control has to be achieved with plastic concrete cut-off diaphragm walls in dam structures. Materials selected for construction of cut-off walls must be durable, impermeable and have stiffness comparable to the surrounding soil.Plastic concrete provides a feasible and economical solution for construction of durable and impermeable cut off walls for dam structures. Plastic concrete wall should not be understood as a concrete wall with similar mechanical properties of concrete used in buildings, piles and spillways sections. Though it consists of the same materials as those of conventional concrete it has the major differences in end product due to predominant addition of bentonite slurry in the mix with very high water cement ratio. This makes the hardened concrete with very low compressive strength less than 5MPa and high failure deformations after the peak load.This technical paper examines a case study, the typical specifications on demand for construction and the issues corresponding to misunderstanding of the material as a structural grade concrete material. Conclusions were drawn based on a few project site quality data and trial mix experimental data. The anomalies in specifications on demand for construction of curtain wall in a dam structure were removed with modifications.INTRODUCTIONDiaphragm walls which are constructed in trenches made of plastic concrete basically serve the function of seepage control under confined measures. They should have the ability to sustain and undergo large plastic strains as compared to conventional concrete. The three basic mechanical properties of plastic concrete cut-off walls are to have least permeability, minimum strength to retain its shape and ability to undergo large deformations under confined loading conditions. The constituents of plastic concrete are cement, bentonite, coarse and fine aggregates, chemical additives to improve flow of concrete and sometimes to retard the setting time and water."

Jan 1, 2017

By K. Rainer Massarsch

The effects of soil displacement caused by pile driving on adjacent piles and structures are discussed. A method is proposed to estimate the point of force equilibrium which makes it possible to calculate up-lift forces and pile head movements. For the case of pre-coring a method is proposed to estimate the stability of the bore hole, based on cavity expansion theory. Model tests were performed to establish the displacement pattern of the soil during the driving of a pile group. It can be concluded that at the ground surface, already installed piles have little influence on the lateral displacements, but reduce significantly the soil heave. During the driving of a pile group, the soil is displaced according to a complicated pattern, which is strongly influenced by the order in which the piles are driven. In clay the displaced soil volume corresponds to the total volume of driven piles.

Jan 1, 1989

By José L. M. Clemente, John R. Davie

"Abstract An extensive pre-production static and dynamic pile load testing program was conducted for a coal-fired power plant. The static load testing program included axial compression, uplift (tension), and lateral load tests. Three types of piles were tested: Monotube, closed-end pipe, and step-tapered. The load tests were used to (a) determine pile driveability characteristics for each pile, (b) verify pile load response behavior, and (c) provide data to support the selection of a cost-effective piled-foundation system for the plant. A recent publication (Clemente and Lewis, 2013) describes the compression load testing program, the interpretation of instrumentation measurement results, and pile selection criteria. This manuscript describes site subsurface and groundwater conditions and installation of probe piles for testing, focuses on the uplift and lateral load testing program, and provides a comparative interpretation of the load test results.INTRODUCTIONThe pre-production probe pile load testing program described here was conducted for a 202-megawatt, coal-fired power and steam generating (cogeneration) facility. A schematic layout of the main plant (power block area) is shown in Figure 1, which also includes the locations of clusters of preproduction probe piles and boreholes drilled near these clusters.The load testing program included 24 pre-production probe piles driven throughout the power block area. The probe piles were driven at locations T-1 through T-8, shown in Figure 1. Three types of piles were driven at each location: Monotube pile; closed end, straight shaft pipe pile; and step-tapered pile. At each location, the three piles were driven in a row with the pipe pile at the center, and the center-tocenter spacing between piles was equal to about 1.5 m (> 3.5 pile diameters for the largest pile). No pile cap was used to connect the three piles, and the three piles driven at locations T-1 through T-8 will be referred to as pile clusters. A complete suite of static load testing (compression, tension, and lateral) was performed on each individual pile at Cluster T-2 and on the step-tapered piles only at Cluster T-8, shown in Figure 1.Clemente and Lewis (2013) provide details of the compression load testing program, the interpretation of instrumentation measurement results, and pile selection criteria. This manuscript focuses on the uplift (tension) and lateral load testing program. A brief summary of the site geology and existing subsurface and groundwater conditions in the vicinity of the test pile clusters is presented, with emphasis on T-2 and T-8. Probe pile driving results at T-2 and T-8 are also presented. Descriptions of the static uplift and lateral load test program at T-2 and T-8 are given along with a comparative evaluation of the load test results."

Jan 1, 2014

By A. B. Desai

The construction of 1144 nos. of piles, each 1.5 m diameter, bored-cast-in-situ type and varying in depths from 6.5 to 23m, has been completed as foundation for 26 piers of 548 m long aqueduct across Orsang river to carry 1128 m3 water of Narmada Main Canal of the Sardar Sarovar Project in Gujarat. These piles are socketed 1.5 m into foundation grade rockmass. The portal system of 44 nos. of piles and pile cap at the top for each pier is analyzed considering the portal fixed at bottom of piles. The borings for pile shaft were done deploying reverse mud circulation rigs and also by conventional chiseling and bailing operations. Besides vertical loading tests and lateral loading test on piles, dynamic tests such as low strain integrity testing on 290 piles and high strain pile testing on 17 piles were also conducted. The results indicated that (a) the settlement/ displacement are much less than the prescribed limits (b) good quality of concrete (c) piles are firmly socketed and (d) piles have adequate structural capacity to withstand the design load.

Jan 1, 1996

By Kazimierz Gwizdala

In recent years, in Poland the ATLAS piles have been successfully applied for some constructions near Gdansk. The piles have been used as foundations for housing and another areas of civil engineering, in delta Vistula geotechnical region, characterized by weak, highly compressible soils represented by mud and peat, lying in sub-surface layers, several meters thick. Usually below are dense sandy soils or gravel. In all cases, the base of ATLAS piles rested on sandy soils. The analysis of pile bearing capacity has been discussed and verified by static pile load tests (SPLT). The load-settlements characteristics obtained were satisfactory. In the paper, the results of geotechnical investigations as well as calculations and load tests are shown. The ecological aspects of ATLAS piles application within highly urban areas of the cities and complex geotechnical conditions are emphasized.

Jan 1, 2006

By Christian Besson

This article describes the implementation of a new jointing process for use between diaphragm wall panels. This process was initially introduced on the SOCATOP work site in uburban Paris (which involved the closing of the western section of the A86 bypass road), on a tunnel ventilation shaft. This brand new system upgrades the potential offered by other types of joints available and enables both ensuring the continuity of panels for structures over 40 m in depth under the strictest safety conditions and constructing shafts with diameters of less than 15 m. A patent for this process has recently been filed.

Jan 1, 2002

By N. Som

The pile capacity in cohesive and granular soils depends on a number of parameters. The values of these parameters as recommended by Indian Standard Code of Practice vary over wide ranges. A designer often finds it difficult to select appropriate values of these parameters for realistic estimate of a pile capacity. The present paper makes a critical review of the values of the parameters given in Indian Standard Code of Practice and suggests a realistic approach to selecting them in the light of recent research.

Jan 1, 1996

By M. Cornelius

Drilled shaft construction through caving soils has historically been an uncertain, risky and costly operation. Uncertain, because the zone of caving may or may not be known, risky because the loss of a shaft is disastrous, and costly because the Contractor, who faces these risks, must include large sums of money in his bid for shaft wall stabilization techniques. This case study will discuss the stabilization techniques that are typically used within the United States, and then present new technologies, born in Europe, that are being utilized in the States by Malcolm Drilling Company today.

Jan 1, 1999

By Michael J. Brown

It is often necessary to undertake some form of pile testing to verify design calculations. Historically this has been limited to static and dynamic tests. Newer rapid testing methods such as Statnamic are seeing more frequent use. This form of testing can be advantageous due to short set up time and test duration. Although the methodology suffers from a lack of formalised guidance and may prove difficult to analyse in certain soil conditions. This paper investigates the suitability of Statnamic testing and analysis for a range of soil and pile types as well as different installation methods through a number of case studies undertaken in the UK. Recommendations are made on test specification and analysis.

Jan 1, 2006

By D. Waite

The Chairman opened the session by wondering why so few papers on Maritime Structures had been received for this conference. Perhaps because the marine environment is so hostile and the access so difficult that engineers tend to be more prudent about new ideas and designs. Dennis Waite noted the number of grey hairs in the room - grey hairs which could be equated with experience gained the hard way. He hoped that this experience would be passed on in the discussion period of this session. The Chairman was delighted to welcome two authors from China, Mr Sun and Mr Liang. He was most grateful on behalf of the conference for their efforts both in preparing their papers and for being able to present them. He regretted that Messrs Noce and Fedolino were not able to present their paper and then welcomed Mr Christensen from Denmark who would present the first paper.

Jan 1, 1991

By experience we know about the natural event of ocean-tides. In geophysics we say that the earth-tides phenomenon is the elastico-viscous response of the earth's body to the attraction potential of moon and sun. By the fact that the tides on the planet take place in a regular periodic frequency, due to the earth rotation of 24 houres for one cycle, the rotation of the moon in about 28 days around the earth and finally to the rotation of the earth-moon combination around the sun in 365 days this phenomenon is a very important one in geophysics. The exact calculation of the acting forces is possible and the comparison of the earth's body response to these forces as well.

Jan 1, 1987

By Camilla Favaretti, Benjamin Turner, Anne Lemnitzer

Pile foundations are extensively used in the construction of various types of superstructures, including tall buildings, bridges, freeways and offshore structures. A fully constrained tip embedment such as a rock-socket offers an attractive solution for achieving significant tip resistance and improving the load-carrying capability of the foundation element. In profiles with very soft surficial soil, rock-socketing often provides the only reliable source of axial and lateral resistance. In preparation of a large-scale testing program on rock-socketed piles at UC Irvine (UCI) geared towards studying the magnitude of shear amplification at the rock-soil boundary of pile foundations, a pre-test model-scale experiment was executed in the UCI Structural Laboratory. The objective of the model-scale experiment was to iterate and validate the test setup, study the influence of important boundary conditions, assess instrumentation techniques and sensor placement, and to gain preliminary insight into the small-scale specimen non- linearity. In addition, this model-scale study provides ample opportunity to compare lateral performance parameters with analytically predicted lateral load behavior using traditional soil resistance functions and limit state analyses and explore new techniques for the derivation of soil resistance functions. The pile specimen had a pile diameter (D) of 10 inches and a total pile length of 125 inches. The pile was embedded in a 40 inch simulated rock socket overlain by 52 inch of medium dense sand (DR~50%). The pile extended 32 inches above the soil surface, where cyclic lateral loading was applied. The pile was installed in a laminar metal frame box with inside dimensions of 39 inches in width (W), 73 inches in length (L) and 86.1 inches in height (H) as shown in Figure 1. During testing, the box was restrained using a rigid bracing system consisting of concrete reaction blocks, wooden braces and steel girders.

Jan 1, 2018

By P. V. Chandramohan

"In ports, piled berths are designed and constructed for berthing of ships with a finite draught. Piles in a bridge foundation also have a large free stand above scoured level. The piles of these structures have to withstand large horizontal forces imparted by the impact of the approaching vessels or due to longitudinal and transverse action in a bridge. It is also imperative that these piles have to project out of the dredged / scoured bed. These piles are normally designed as slender compression members subjected to bending also. They are subjected to vertical load tests for assessing the soil resistance. Lateral load tests, as a rule, are also stipulated. IS and IRC codes stipulate a deflection criteria for lateral load test to arrive at the capacity. These tests are usually conducted on a working pile by jacking out two piles. At the time of the test, pile will be free headed. But in service, piles are fixed head. There is a large difference in deflections between a fixed head and a free headed pile. Besides, a free headed pile will be subjected to a much higher bending moment than the fixed head one. This will put the working test pile under risk of breaking during the test. The problem is analyzed with case studies. INTRODUCTION Vertical capacity of piles is assessed by static formulae. This formula is based on the soil properties obtained from random soil exploration and laboratory and in-situ testing. Since soil is not a homogeneous medium, properties can vary. The design parameters taken for computations may be different from the ones at the interface of the pile with the soil. The best way is to find out is by a load test. The code IRC:78-2014 has rightly stated that initial load test is part of the design process. This is true with the vertical load test. But there are certain problems with the purpose and inference of the lateral load test. In both the tests the criteria for acceptance is the quantum of movement of the point of application of the load. In the former, the movement is vertical and depends more on the compression of the soil than the compressive strain in concrete. But in the latter, this movement is partly on account of the flexural rigidity of the pile and partly due to the horizontal compressibility of the soil. The role of rigidity of the pile is more when compressibility of the soil is higher. Lateral load test is done by jacking one pile against another because it is difficult to get an independent horizontal reaction. Please see Fig.1 Photo."

Jan 1, 2015

By B. M. Das

Laboratory model test results for the ultimate uplift capacity of rough rigid single and group piles embedded in sand have been presented. Model tests on single piles were conducted in loose, medium, and dense sand. The uplift tests on group piles were conducted in medium sand only. Based on the present model test results, tentative relationships for the estimation of the ultimate uplift capacity of single pile have been presented. The efficiency of group piles is a function of the length-to-diameter ratio, center-to-center spacing to diameter ratio, number of piles in a group, and the degree of compaction of sand.

Jan 1, 1989