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By Allan Sylvester

Construction of the Shot Tower Metro Station in Baltimore, Maryland was performed in two phases. In the first phase, a contractor was retained to excavate the station in order to construct twin tunnels from the Shot Tower Station to the John Hopkins Station. The retention system for this 70' deep excavation consisted of a Soldier Pile in Tremie Concrete (SPTC) wall supported by cross-lot bracing. In phase two, The Clark Construction Group, Inc. was retained to construct the station interior structure, two entrances, two station ancillary shaft structures and the track work for the station and tunnel. The excavation for the construction of the two entrances adjacent to the 70' deep station SPTC wall had to proceed prior to completion of the station structure due to the tight construction schedule. A system of overlapping secant piles was specified as a vertical support of excavation element for the West Entrance. The secant piles would have provided a watertight, rigid support to resist the load from the SPTC wall constructed in phase one. A watertight system was required in order to minimize the settlement of adjacent buildings supported on wood piles. Clark Construction was concerned with the constructability, cost and performance of the specified secant piles and looked for other innovative methods of providing a watertight and rigid system. Substitution of a reinforced slurry wall in lieu of the secant piles was cost prohibitive due to the additional cost of concrete placed under tremie. Clark, being familiar with cement-bentonite cut-off walls and slurry wall construction procedures, proposed the construction of a PSHG wall, in lieu of the secant piles. The PSHG wall construction consisted of trenching 30" wide by 20' long by 60' deep panels under a self-hardening slurry. Once the excavation for a panel was completed, a 60' deep prefabricated soldier beam and lagging panel was placed in the slurry. The slurry design mix then self-hardened within the cure time, allowing excavation for the structure to proceed This paper will discuss the design, details and construction methods used on the PSHG wall and will compare the advantages of the PSHG system to conventional support systems.

Jan 1, 1997

By Tracy Brettmann

Equipment ? Hollow Stem Auger ? Drill Bits ? Leads/Torque Arm ? Hydraulic Gearbox ? Hydraulic Power Unit ? Grout Pump ? Crawler Crane

Jan 1, 2004

By C. Vipulanandan

It is critical to monitor the ground conditions during excavation and drilling of boreholes during construction to identify possible changes in the soil and rock formations. Drilled shafts are increasingly used as foundations to support structures, bridges and other facilities in geomaterials such as soft-rocks and hard clays. Locating the bottom of the borehole during construction with the required design strength is critical. Hence developing a simple device that could be easily adapted/used with the drilling tool was of interest in this study. Determining the shear strength of the geomaterial in the borehole and at various elevations including the bottom of the borehole can lead to better quality control of construction by identifying the various layers based on strength. In this study, a down-hole penetrometer (DHP-CIGMAT) was designed, built, calibrated and tested in the field to determine its effectiveness in measuring the strength of soil/soft rock in the boreholes. Based on limited field tests, linear correlations between geomaterial strengths and DHP-CIGMAT deflection have been developed. The DHP-CIGMAT can be used to identify soils and soft rocks.

By Reda M. Bakeer

"An approach slab is the roadway segment that immediately follows a bridge intended to provide a smooth transition between the two elements. Some approach slabs have developed rough rideability with time due to differential settlement between the roadway embankment and the bridge. Soils in south Louisiana are generally poor and highly compressible and, therefore, pile-supported approach slabs were occasionally used. Timber piles of variable lengths are driven into the soft soils where no appreciable toe support exists. This resulted in the soils both supporting loads through shaft resistance and yet experiencing long-term consolidation settlement. Field testing and review of the records of over 120 approach slabs constructed in south Louisiana yielded the conclusion that their performance is primarily governed by negative skin friction (downdrag) imposed on the relatively short timber piles. A software (TU-DRAG) was developed to evaluate the deflection profile of a pile-supported approach slab based on its geometry and conditions of the underlying soils. It evaluates the effect of dragload considering the number and spacing of the piles at each transverse row and their variable lengths along the approach slab. TU-DRAG was utilized in the design of two transportation related projects which have been in service for more than 10 years.INTRODUCTIONThe problem of differential settlement at bridge approaches or “the bump at the bridge” has been recognized for many years. Research studies (1986, 1989, 1997, 2009 and 2013) by the Transportation Research Board (TRB) and the Federal Highway Administration (FHWA) provided comprehensive evaluations of the performance of bridge approach slabs by assessing their field conditions and construction and maintenance records. Various states have also performed their own studies to investigate the performance of bridge approach slabs. The studies considered various types of structures including soil- and pile-supported approach slabs, integral bridge abutments and open-end abutments. Recommendations were provided for the design of new structures and for maintaining and repairing existing structures. Guidelines were offered regarding tolerable movements of bridges and their foundations based on measurements of vertical and horizontal movements of 580 bridges Moulton (1986). Vertical and horizontal movements greater than 102 mm (4 inches) and 51 mm (2 inches), respectively, were considered intolerable. Tolerable limits for angular distortion (differential settlement to span length) were suggested to be 1/250 and 1/200 for continuous and simple spans, respectively. It was reported that a differential settlement greater than 13 mm (0.5 inch) at the bridge interface would be sufficient to constitute a “bump” requiring mitigation."

Jan 1, 2017

By H. Mori

The session chairman, Dr. H. Mori, welcomed the delegates to Discussion Session 8. AUTHORS PRESENTATIONS 1 . G. Price, Building Research Establishment. UK Mr. Price expanded on the content of his paper and presented elements of various case histories of bored piles instrumented by the Building Research Establishment. In particular, the interpretation of data from instrumented piles is critically related to: (i) the construction process (ii) concrete stiffness and variability (iii) the effects on the pile due to installing instruments The main role of the instrumentation in the examples presented was to establish pile performance under service loading conditions. Of particular interest is the mobilisation of skin friction and soil shear modulus.

Jan 1, 1991

By M. Pernot

A 12 m-deep excavation has to be perfomed in the Shanghai soft clay to install an underground electric substation. This article was originally intended to study the behaviour of the wall, the excavation bottom and the surrounding ground during the excavation. Since the works are behind schedule, and the data referring to the excavations are not, therefore, available, the article is limited to a presentation of the analysis methods that we envisaged for the study of the behaviour of the excavation.

Jan 1, 2010

By William Van Impe

A most renewing and promissing soil displacement screw pile is called the O-pile. The O-screw pile is a soil displacement auger pile based on a screwing in - screwing out procedure. The displacement auger head consists of a discontinuously diameter - increasing steel tip, on top of which the continuous screw flange with variable pitch is mounted. The soil displacement is kinematically ensured by downwardly oriented slots mounted on the auger head at different well chosen locations on the flanges. This leads to a very efficient lower energy screwing-in sequence of the pile and consequently to a high penetration rate. A test loading program of instrumented O-piles has been carried out in order to evaluate the load settlement behaviour, the shaft and tip capacity of the O-pile, including its specific installation parameters.

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 Gao Dazhao

This paper presents some research results of pile foundation performance. Measurements on the bearing behaviour and driving effects of piles have been carried out during pile testing and pile driving. It has been found that the ratio of end resistance to the ultimate load depends on the pile length, and the ratio in general is less than 40% for single piles. However for pile group, the end resistance seems to be greater than skin friction. The characteristic curves of skin friction and end re­sistance appear as interaction between soils and pile. The contribution of skin friction to the pile bearing capacity not only depends on soil properties but also on the relative position of the soil layer. The pore pressure and the lateral pressure in ground have been observed during the stage of driving piles. Based on the available data, the radius of plastic region and the coefficient of pore pressure A can be found analytically. The pore pressure time process curves which may be used for practice have been predicted by means of numerical method.

Jan 1, 1991

By Jerry F. Parola

In current practice, pile foundation design is based on a general under-standing of pile-soil interaction during installation and superstructure-pile-soil interaction after construction. The pile design is a reflection of experience, precedent and judgment for normal piling practice of working load capacities up to approximately 100 tons with corresponding ultimate capacities up to 200 tons. For higher capacity piles, pile design is even less predictable. In particular, the feasibility of pile installation is an important design consideration that must be given the proper attention. An installation capability that is not given the required emphasis can cause unnecessary problems.

Jan 1, 1986

By A. Mazzucato

This paper presents the experimental results of driving and load tests on an instrumented pile driven into a test pit filled with fine homogeneous sand.

Jan 1, 2010

By Masaki Kitazume

Deep mixing method, in-situ admixture stabilization technique, has been developed and adopted for on land and marine construction works in Japan. The geotechnical design procedure of the method has been standardized in Ministry of Land, Infrastructure and Transport Government of Japan for port and harbor facilities, which includes the block type and wall type improved grounds for foundation stability, settlement reduction purpose. This procedure is based on the allowable stress concept, in which the induced stresses within the improved ground are confirmed to be lower than the allowable strength in the internal stability calculation. This procedure has been cited by several organizations to establish their standards. The Ministry has a plan to introduce a reliability based design for marine construction works in 2006, in which the design procedure on DM improved ground will also be modified to the reliability based. In the new design procedure, the average and variation of soil parameters and external loads are incorporated by partial safety factors to investigate the stability of improved ground. According to the plan, the author has been studied the design procedure and the magnitude of partial safety factors, and has established a preliminary draft of the standard. This draft will be brushed up through comparing the current design procedure. In this article, the design concept and design procedure of the method are briefly described.

Jan 1, 2004

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

After the Loma Prieta Earthquake, which caused major damage to viaducts in the Bay Area, the California Department of Transportation set up a test programme for foundation piles. Funderingstechnieken Verstraeten B.V., beter known as Fundex, was approached, since one of the piling systems of Fundex, named Tubex, is extremely suitable in areas sensitive to earthquakes and we were very much interested to prove the capabilities of this piling system. Equipment For the installation of Tubex and Tubex grout-injection piles special piling equipment is required. Since our company is not only a contractor, but also a designer and manufacturer of piling equipment, all special equipment for our range of foundation techniques is designed and built by our own piling equipment department. For the installation of both Tubex piles and Tubex grout-injection piles for the Caltrans test programme, the following pieces of equipment were selected: a) Fundex F12 piling rig b) Drill table c) Hydraulic powerpack d) Grout mixing unit and high pressure pump

Jan 1, 1993

By Steven M. Henderson, Zachary D. Jones

The risk of allocation in construction contracts is a primary concern for all parties. For contracts involving subsurface construction the allocation of site condition risk is critical. In the past one hundred years technological advances fundamentally changed how that risk is allocated; yet another shift in this risk allocation may lie just over the horizon due to advances in geotechnical data management. Around the world initiatives are underway to make geotechnical datasets more open and accessible. In the United States some states like Kentucky have already made geotechnical data readily accessible. This proliferation of geotechnical data in the U.S. may impact the allocation of subsurface risk in construction contracts. Many construction contracts contain a differing site condition clause. That clause allows for a modification of the contract price or schedule if the ground conditions encountered by the contractor differ materially from either what was indicated in the contract documents or would be reasonably expected. A contractor, however, is typically not entitled to that modification if the contractor knew or should have known of the adverse conditions encountered. Courts have interpreted the “should have known” language as requiring contractors to make a reasonable site investigation prior to bidding the project. If geotechnical data is available and accessible and reveals the adverse condition the contractor encounters, courts could find that the contractor should have known of the condition and thus will not be entitled to a modification based on the differing site condition clause. Accordingly, the U.S. could be on the threshold of significant shifts in how the risk of differing site conditions is allocated in construction contracts.

Jan 1, 2017

By James A. Schneider

The successful installation of long piles driven into very dense sands relies on the occurrence of the reduction in local friction with increased pile embedment, a phenomenon known as ?friction fatigue?. The underlying mechanisms controlling friction fatigue are poorly understood, with some design methods including an adjustment for the influence of pile diameter while others do not. This paper back calculates the installation resistance of 0.356m to 2m (14in to 78in) diameter open ended piles driven into very dense sands using wave equation analyses. Cone penetration test data are used to link soil properties to installation resistance. The study illustrates consistent interpretation of a variety of case histories of open ended piles driven in very dense sands using newly developed analysis techniques and normalized parameters. Results provide information on methods for incorporating friction fatigue into drivability studies as well as a discussion of mechanisms related to pipe pile installation resistance in sandy soils.

Jan 1, 2010

By [D. N. ] Naresh

During different activities pile installation like pile boring, concreting etc., it is likely that various problems, depending up on site condition may be encountered. There are possibilities that some of the activities if not correctly followed may affect the pile capacity. This paper describes few problems encountered during pile execution at different sites and presents the remedial measures undertaken to overcome them.

Jan 1, 1996

By Gyimah Kasali

Rapid Load Testing was performed as part of an extensive drilled pier testing program for the University of California Berkeley Capital Improvement Program. The purpose of the program was to: (1) Verify the axial compressive design capacity values for the planned 24" piers, and to estimate the capacity of the existing 30" CIDH piers, and (2) To evaluate the seismic performance of the proposed drilled shafts. The Fundex PLT was used since the loading period of the PLT is very similar to the period of a seismic event, making it an ideal tool to model the pier response to seismic events. "Performance-based design" of structures subject to seismic loads has been of particular interest to UC Berkeley Seismic Review Committee and the Pacific Earthquake Engineering Research Center. The comparison of static tests to Rapid Load testing also provided valuable correlations. The program represents one of the most comprehensive drilled pier test programs on the West Coast. The testing program consisted of Rapid Load Testing using the Fundex PLT on 6 drilled piers. Rapid Load Tests were followed by conventional static compression and tension tests on selected piers, followed by another cycle of rapid load tests on the statically tested piers. The piers featured extensive instrumentation to allow detailed interpretation of the test result. Correlations were drawn to compare static load test result to that of the PLT in the particular soil profile, and the PLT also provided the data to analyze the ultimate seismic capacity of the piers. The load test results indicate that the ratio of interpreted failure load from the PLT data to the corresponding load from the static load test data is about 1.2 to 1.3 for the clayey soils underlying the test site. The results also indicate that the PLT offers an economical approach to defining the stiffness of drilled pier foundations subjected to seismic loads for use in performance-based design.

Jan 1, 2002

By A. V. Shroff

The Indian Standards code of practice for design and construction of underreamed piles contains provision for installing such piles in expasive soils. In recent years, a large amount of research work has been carried out in the analysis, design, construction and performance of underreamed piles in expansive soils. This paper suggests that the results of this research field tests should be included in the code. Various additions and modifications as well as deletions that should be incorporated in the code are discussed.

Jan 1, 1996

By Franklin M. Grynkewicz

As part of the Boston Harbor clean up project, the new 1,000 mgd Deer Island Sewerage treatment plant includes ten 240 feet high egg-shaped "residuals" tanks. Contract documents called for these structures to be supported on 2,600 sixteen inch concrete filled pipe piles. The project site is underlain by highly variable glacial and marine deposits. Subsurface conditions vary from one extreme where firm glacial deposits exist at subgrade to the other extreme where 70 feet of medium stiff clays overlying weathered bedrock must be dealt with. The most common profile consisted of 15-20 feet of sands, 20-40 feet of marine clays, and 20-60 feet of stratified glacial deposits (commonly called tills) overlying Argillitic bedrock. Post bid redesign work, initiated as a cooperative effort between the owner and the general contractor, demonstrated that an $8 million savings could be realized if high capacity 48 inch diameter caissons replaced the specified pipe piles. A highly unusual arrangement of having the general contractor and specialty subcontractor providing input to the owner's engineering team allowed the redesign work to proceed on a "fast-track" schedule.

Jan 1, 1992