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By Dhanvin B. Mehta

Pile testing is generally understood as static load test. It is our common experience that for high capacity, large diameter bored piles, static testing is expensive and time consuming. It is practically impossible to test large number of piles by traditional testing methods. The escalating cost in carrying out a static load test, as well as incomplete information derived therefrom compelled researchers in United States to look for an alternative method of testing for both bored and driven piles. The original research work was carried out at Case Western Reserve University in early 70's, under the funding of Federal Highway Administration as well as several State Depts. of transportation in United States. The outcome of the research was the development of a state of art field computer for capacity determination, based onOne Dimensional Wave Mechanics.

Jan 1, 1996

By Walter Kaeck

In a recent upgrade of their system, Amtrak converted a bascule type draw bridge over the Thames River to a vertical lift structure supported by the existing piers. During the bridge replacement, significant settlement occurred on one of the piers and movement continued thereafter. Construction was stopped as Amtrak became concerned as to how much the subsequent construction activities would cause the pier to further settle and tilt, not only impacting the operation of the existing bridge, but also jeopardizing the new lift span. Mueser Rutledge was engaged at this time to help understand and solve the problem. A remedial grouting program was developed to arrest the settlement. As a subcontractor to Cianbro Corporation, Pittsfield, ME, The Judy Company was hired to perform the remedial grouting work. Work platforms were constructed around the pier for support of the drilling equipment. A dual string drilling system was used to install sleeve pipes at depths of up to 185? below the water level. Ultrafine cement grout stabilized with additives was placed at 2.5 foot intervals through the depth of the sand and gravel stratum below the bottom of the pier. Logistics were difficult and the schedule was severely impacted by the remedial work, necessitating working six 12-hour shifts per week and working in the river through the winter months. After four months of drilling and grouting, movement of the pier stopped. At the conclusion of the remedial work, more than a million gallons of ultrafine cement grout were placed. Confirmation borings recovered completely solidified material with compressive strengths ranging from 500 to 1500 psi. The bridge replacement was then completed and is functioning. Continued monitoring through July 2009 shows negligible movement.

Jan 1, 2009

By C. Dai, S Raathiv

The Waikato Expressway is one of the New Zealand Transport Agency’s (NZTA) seven roads of National Significance. Coffey is part of the City Edge Alliance engaged by NZTA for the Hamilton Section of the project. The 22km Hamilton Section is the largest and most geotechnically complex section of the Expressway. The Mangaonua gully in Sector 6 is the most challenging geotechnical area of the project for piling works. Together Coffey and Brian Perry Civil have carried out the temporary and permanent design and construction of embankments, piling works, retaining walls and soil improvement works for the bridge construction. The design and construction works were governed by weak alluvial layers and artesian pressure layers several meters beneath the ground level. This paper presents the action taken to improve the foundation of temporary platform, control the artesian pressure, prevent bentonite leakages into the highly permeable alluvial layer and challenges in the base grouting process. This paper summarises the key components in the construction and supervision of bored piling works and outlines innovative solutions for challenges which we faced during the construction.

Nov 1, 2022

By Andrew Rietz, Yu Bao, Steven Halewski

"HP-Pile foundations are the most favorable type of foundations for bridges because of their constructability, versatility with regard to subsoil conditions, and settlement controllability. For many years, bridge engineers have puzzled over the most economical way to orient HP-Piles: Should the strong axis be oriented in the longitudinal direction or in the transverse direction? The accurate design of foundations may considerably reduce construction costs. In order to answer this question, 3-D finite element models will be set up to analyze the effects of pile orientation on bridge behavior. Because seismic loading usually controls the structural design in seismic zones, it is important to investigate the effects of pile orientation under such loading. HP-Piles are designed conservatively due to the uncertainty of the dynamic soil-structure interaction during earthquakes. For the bridge substructure, the soil’s stiffness plays an important role in load distribution as the soil and piles act as a combined system to resist the seismic loading. The dynamic soil-structure interaction mechanisms of bridges in both the longitudinal and the transverse directions will be investigated through the use of 3-D finite element models. The numerical models will realistically simulate the soil-pileabutment- wingwall-superstructure system subjected to seismic loads. Nonlinear soil springs will be employed to model the non-elastic soil behavior. The analysis will provide theoretical support to the design practice.IntroductionAs sustainability has asserted itself in the public’s eye, bridge professionals have rushed to develop criteria for sustainable bridges. The three main categories that define and distinguish sustainable bridges are: lower energy input, increased durability, and simplified deconstruction. By optimizing the structural members, the engineer is able to reduce the material quantities for the bridge, effectively reducing the energy input for the bridge (Hunt; Whittemore). A deeper understanding of soilfoundation- structure mechanism will facilitate sustainable bridge design by lowering energy input and increasing the service life of bridges (Rietz et al.)."

Jan 1, 2017

By David R. Black

Foundation problems due to collapsible and expansive soils are well known throughout the arid western United States. Millions of dollars are spent annually to counteract the effects of such soils for both new foundations and existing foundations suffering from settlement or heave. Over the last 20 years helical screw piles have come into wide-spread use as a permanent deep foundation element for these problem soils, especially in the arid western United States where, in some areas, they are a standard of practice. Independent research resulting in recognition by every national building code in the United States has legitimized helical screw pile technology. Once thought of in terms of light structural underpinning, helical screw piles of today are designed to take heavy structural loads, vertical and lateral, tension or compression, including seismic loads. With proper pile grouping, design capacities for column loads over 4,500 kN (1,000 kips) are attainable. This paper discusses design considerations specifically dealing with collapsible and expansive soils: soil investigation parameters, predicted settlement and long-term creep, heave in expansive soils, downdrag in collapsible soils, shaft slenderness buckling, maintaining shaft alignment during installation, refusal condition, water migration along the shaft, lateral loading, cyclical loading for seismic loads and machine foundations, corrosion, helix durability during installation, the installation torque vs. capacity equation, and design methodology. The paper concludes with several case histories where helical screw piles were used for new structural foundations and to underpin existing failed foundations in St. George, Utah, Cedar City, Utah, and Denver, Colorado, USA, sites of some of the most expansive clay and collapsible soil in North America. Soil descriptions and performance histories are presented.

Jan 1, 2002

By A. C. Ackenhell

The geologic environment of Pittsburgh, Pennsylvania is both inviting and challenging to drilled pier installation. The shales and clayey soil zone of the hills are favorable but the alluvial soils of the three major rivers create problems. Beginning in the early 1950's, drilled pier installation continually improved as methods were developed to meet the geologic challenge. Case histories are presented to illustrate the historical development of piers in Pittsburgh. Recent innovations reducing the groundwater problem are illustrated by a case history of a high rise building construction. Load test information for side wall shear on the cylindrical shaft area between the concrete and bedrock continues to be desired but remains generally uneconomical.

Jan 1, 2010

By Terence P. Holman

Micropiles are employed to retrofit existing foundations, including underpinning prior to future construction operations and resupport of existing structures that have experienced distortion and settlement. This paper presents analyses of the two case histories requiring the use of micropiles in these applications. The first case history involves micropiles used to resupport a settled pump station next to an excavation which had suffered basal failure and ground loss. A compression load test pile experienced plunging failure which, after analysis of the strain-gauge data acquired during the test, was attributable to a greater degree of disturbance to the subsoils beneath the site than anticipated. After construction of the micropiles around the pump chamber a synchronized jacking system was used to lift and right the 320 kip chamber structure, followed by resupporting it on the newly constructed piles. The second case history entails the use of micropiles for direct underpinning support of existing columns prior to a utility tunnel installation within an existing high-bay warehouse structure. The design constraint that most significantly affected the successful completion of this project was the desire to bond the new piles into the existing reinforced concrete foundations. As a result of the coring method through the footing, the ultimate bond stress measured during a pullout test was more than twice that assumed in the design. Monitoring of the underpinned columns during trench excavation indicated that the system performance was acceptable. These case histories reinforce the concept that lower capacity micropiles can provide a rapid means to underpin and retrofit existing structures.

Jan 1, 2007

By D. M. Holloway

As a part of the 1-15 Reconstruction Project, static and dynamic (high-strain) testing methods formed the basis to estimate long-term axial capacities, and to assess the magnitudes of bearing capacity gains (setup) from the end of installation to the time of static/dynamic tests weeks later. This paper summarizes the results of nine full scale pile load tests to failure in compression, and how the designers used these data to finalize pile selection and penetration criteria bridge-by-bridge in the final design stages. Soil conditions along the project alignment ranged from deep, lightly over-consolidated Lake Bonneville clays interbedded with granular strata of varying consistency, to sites dominated by dense alluvial deposits of cohesionless soils well above the water table. The test sites were selected to bracket the conditions that are expected. Twelve-, 16-, and 24-inch-OD pipe piles are to be used to support the new bridges. The team plans to impact-drive all piles closed-end to final penetrations. The test piles varied from 35-ft-long pipes driven to refusal in the shallow dense sands at some sites, to 115-ft-long pipes stopping at 3 blows per foot in predominantly cohesive deposits. The capacities gained with time proved to be reasonably predictable, and significant setup was noted both in the cohesive and cohesionless strata. The test program objectives included providing the means to estimate long-term capacities from short-term (24- to 48-hour) restrikes following installation of foundation piles during production driving operations.

Jan 1, 1998

By Arturo Ressi di Cervia

"The Construction of the Thrust Pits for Jacking of the I-90 Tunnel for the Central Artery/Tunnel Project (Part of Contract No. C09A4) in Boston MA was nominated for DFI’s 2002 Outstanding Project Award. In the judging, the project and the specialty subcontractor, Treviicos Corporation, was chosen for a Special Recognition Award. INTRODUCTIONBoston’s Big Dig, as the construction of the underground artery became known, is undoubtedly the largest urban construction project of this century.The Central Artery/Tunnel Project, or CA/T, to call it by its proper name, runs approximately eight miles through the heart of Boston, five miles of which are built underground while maintaining traffic on the elevated existing structure, while at its southern end I-90 is extended to Logan airport under active rail lines, Fort Point Channel and Boston Inner Harbor.Since the alignment of the road closely parallels the shoreline as it existed in colonial times, the cut and cover construction had to contend with substantial portions of filled ground, not to mention existing subway lines, live utilities, building foundations and, last but not least, the irritable Boston drivers and litigious adjacent property and business owners.Consequently, while it is impossible to single out the most difficult or challenging contract, the jacking of the tunnels of I-90 under the live rails of Amtrak certainly will rank high on the list.Never before, anywhere in the world, was an attempt made to jack tunnels of this size: the South Bay Interchange consists of three 78 feet (24 m) wide by 38 feet (11.6 m) high tunnels, the shortest of which is 167 feet (51 m) long. TECHNOLOGYIn order to achieve this engineering feat it was necessary to consolidate the soil under the track to prevent it from moving or settling during the jacking process. After a detailed analysis of the geological profile to be traversed it was decided that freezing was the most suitable method, since it could be applied to the full range of soils present on the proposed alignment."

Jan 3, 2003

By Silas C. Nichols

FHWA Interest is due to: ? An increase in successful projects in the U.S. private sector and in other countries ? Cost effective and more efficient in many circumstances ? Agency Priorities - FHWA "Vital Few" AASHTO TIG

Jan 1, 2005

By A. Flora, E. Bilotta, F. Foria, V. Nappa

"All the typical applications of deep mixing rely on the good mechanical properties of the improved columns to strengthen or stiffen the ground for a number of geotechnical applications.This paper focuses on a completely different kind of deep mixing, carried out in order to obtain columns much softer than the surrounding soil. This kind of deep mixing, named Soft Deep Mixing (SDM), is introduced as an original means to tackle seismic risk, and can be convenient when the existing structure to be protected has a historic relevance that cannot be altered with structural modifications. The idea is that properly assembled layers made of partially overlapped SDM columns, with dynamic impedance much smaller than that of the surrounding soil, will filter and reflect most of the seismic energy.The paper presents the results of some 2D parametric numerical analyses aimed to investigate the seismic performance of this innovative approach. Simplified dynamic inputs (Ricker wavelets, having only one largely predominant frequency) were adopted to better understand the effect of signal frequency. The analyses show that the effectiveness of the soft grouted isolating barrier depends on soil and SDM geometrical, physical and mechanical properties, as well as on the frequency content of the seismic input.INTRODUCTIONPassive structural systems installed at the foundation level of existing buildings are a common solution to protect them against earthquakes. However, installation procedures are expensive and not always feasible, as for instance in the case of valuable buildings. As an alternative, ground improvement techniques can be used to modify ground properties, in order to mitigate the intensity of shaking at ground level. The propagation of shear waves in the ground can be modified by introducing a layer of artificially modified material, having a dynamic impedance (defined as n =p VS, where p is the material density and VS the velocity of shear waves) very different from that of the natural soil. Both very high or very low values of the dynamic impedance of the grouted soil (nt) can be effective in reducing the overall transmitted energy, with the difference that – for a given reduction of the transmitted energy - stiff grouted layers tend to filter the low frequency components of the amplitude spectrum without modifying in a significant way the high frequency components, while soft grouted layers have the opposite effect. Then, ideally the choice of the best grouting technique should be made considering the effects of the different frequency components on the building to be protected. These effects are detrimental for the structure when they are close to its natural frequency: high frequency components result into large structural loads on massive squat structures (high natural frequency), and low frequency components may be critical for tall and flexible structures (low natural frequency). Therefore, the typical procedure of stiffening the uppermost soil layers regardless of the kind of building to be protected is not necessarily beneficial, and for the case of squat structures soft grouting should be preferred. However, this procedure has not been taken into account yet in the engineering practice, and may pose static problems at ground level (i.e. excessive static settlements)."

Jan 1, 2015

By Murray Gamble

A new type of groundwater cutoff wall has been developed at the University of Waterloo. The Waterloo Barrier? is a steel sheet piling system that incorporates a sealable cavity at each interlocking joint. In order to prevent leakage through the joints, the sealable cavity is flushed clean and injected with sealant after the installation of the piling. The installation and sealing procedures of the Waterloo Barrier? system allow for a high degree of quality control resulting in a very low permeability cutoff wall. Based upon field installations, the bulk wall hydraulic conductivity of the Waterloo Barrier? ranges from 10-8 to 10-10 cm/sec. Recent case histories are presented in which Waterloo Barrier? vertical cutoff walls have been used to prevent the off-site migration of contaminated groundwater or soil gases. In some instances, the Waterloo Barrier? system was used in combinations of applications such as preventing the migration of contaminants, redirecting the flow of groundwater, providing structural shoring for soil excavation and aiding in site de-watering processes.

Jan 1, 1997

By Peter Deming

"PART 2 OF 2 (CONTINUED FROM SUMMER 2006 EDITION) CONSTRUCTION ISSUES (cont’d) The Influence of Ground Conditions on Collapse Sand and gravel strata provide frictional resistance to support active earth pressure. The angle of internal friction has only slight influence on computed stability. Sand and gravel material design parameters can be defined with SPT N-values. Silt strata should be analyzed using internal friction. Definition of soil parameters should be performed by laboratory testing. Cohesive materials, especially soft clay and peat, require careful definition for design. Shear strength should be determined by laboratory testing. Work platforms constructed over granular strata improve the ground resistance by increasing confining pressure. However, temporarily increasing overburden stress on cohesive ground reduces trench stability. If the ground contains soft cohesive deposits which are not normally consolidated to the construction overburden, these must be stabilized before attempting trench construction. Use of wick drains and surcharge fill to improve the ground is recommended. Ground stabilization work requires time, and should be performed by the Owner prior to trench excavation. The addition of cement, stone columns, or other measures to support trench excavation equipment is typically determined to be more expensive and less dependable than ground improvement. Excavation through peat can be especially problematic. Peat materials rapidly compress when earth pressures exceed preconsolidation stresses. Backfill materials provide a horizontal stress on the trench wall which can exceed the bearing capacity of peat. As the peat compresses, the trench becomes wider, and slurry levels drop and trench stability can rapidly deteriorate. If the peat is the closure layer, a shallow key is recommended. If peat is present on the trench wall, preconsolidation with surcharge is recommended. Bottom preparation and Backfill Placement Trench wall stability is a temporary condition which must be controlled by proper design and construction of work platforms and slurry features which influence ground support. Backfill materials and intimate contact of the backfill with the closure layer are permanent conditions which are the end goal of the work. The most common reason slurry trenches fail to provide working barriers is improper bottom closure. Either the closure layer is not engaged, or the backfill is not in intimate contact with the closure layer. This can result from construction problems associated with sidewall collapse described above, slurry performance and/or degradation, backfill placement methods, and failure to maintain the trench bottom clear of sediment prior to placing backfill."

Jan 1, 2006

By Anthony T. C. Goh, Zhiye Zhao, Laddu B. Jayasinghe, Hongyuan Zhou, Yilin Gui

"Ground vibrations from blasting are undesirable and they are very short in duration with high principal frequencies and high amplitude. Structural response to that kind of excitations may differ significantly from that generated by lower-frequency earthquake vibrations. In practice, the damage to nearby structures to generated ground vibrations has been controlled by various codes and regulations available. However, the existing vibrations limits are not always applicable, as they depend on the geological conditions of the site and the dynamic characteristics of the structure. This paper investigated the influence of the rock-soil interface on the response of pile foundation to ground-borne vibration from rock blasting, through numerical simulations using finite element software LS-DYNA. It is found that the slope of the rock-soil interface greatly influences the location of damage and the extent of damage on the pile. The bottom of the pile is subjected to a larger blast pressure and stresses are highly concentrated at the pile bottom. Thus, the pile bottom can fail in shear before it reaches its plastic moment capacity.INTRODUCTIONDrilling and blasting is the widely accepted method to large-scale rock breaking activities in civil engineering constructions due to its cost effectiveness, higher efficiency and ability to break hard rock. However, ground vibrations from blasting are undesirable and it can cause damage to nearby structures. In practice, the damage to nearby structures to generated ground vibrations has been controlled by various codes and regulations available. The existing vibration limits are not always applicable, as they depend on the geological conditions of the site and dynamic characteristics of the structure.Pile foundations are commonly used as foundations of high-rise buildings and bridges to transfer the heavy loads from the superstructure above through weak compressible soil strata into deeper, competent soil layers which have adequate capacity to carry these loads. In engineering practice, many piles are normally designed to carry mainly vertical loads and very little lateral loads, as typically the vertical loads (the gravity) are significantly larger than the horizontal loads such as wind loading. However, in recent years, there have been a number of reported case studies of translational soil movements that have induced stresses and bending moments that have damaged pile foundations and in some cases resulted in collapse of the superstructure. Typical lateral load include nearby construction activities such as an excavation for a basement or slope, the construction of a road embankment or a tunnel, as well as earthquakes (Abdoun 1997; Goh et al. 1997; 2003; Chen et al. 1999; Dobry et al. 2003; Boulanger et al. 2007; Black et al. 2007)."

Jan 1, 1900

By Davide Grassi, Joel Joaquin Cortez, Giovanni Spagnoli, Nick Chittenden

Grouting is a technique used to improve the engineering properties of soils and rocks. Grouting techniques are classified under different criteria: injection method used, type of grout material injected, typical application, and the sequence of construction. The best-known criterion is the mode of entrance or admission of grout into the soil or rock. It is possible to identify therefore several grouting techniques: compaction, fracture, jet/mixing and permeation. The function of penetration grouting is to reduce the permeability of the soil or rock and/or increase the strength and density. In order to avoid displacement, permeation grouting shall be carried out at carefully controlled pressures and flow rates, using appropriate grouts. Colloidal silica is an innovative binder which has low viscosity (about 5 m·Pas), it is not toxic (pH lower than 9) and it is workable between +5°C and +45°C. This paper presents several case histories: a consolidation job related to the installation of a new sewer in North Italy in cohesionless soils, water stopping injection in a weathered granitic bedrock in California, permeation works in the US in sandy soils to improve excavation and the installation of sheet piles in the UAE. Results show that the colloidal silica an innovative and robust technology to perform grouting in very fine soils where conventional binders or micro-fine cements cannot penetrate.

May 1, 2022

By Michael Arnold, Robert Bachus, Michael Bracher, Jamey Rosen, Robert Roff

"For a high hazard USACE facility, the Center Hill Dam in Tennessee, several disparate streams of data were compiled into a single geospatial and relational enterprise data management system to store, analyze, visualize and distribute the data collected during installation of a deep cutoff wall. These data streams included historical drawings and pre-construction plans and grouting records; geological data from boreholes; attributes of barrier wall elements; element verticality data analyzed from multiple measurement methods; and concrete field and laboratory analytical data. A previously developed data management system developed by the authors, WallTracker, was extensively modified to also include manually collected and real-time measurements from several types of dam monitoring instruments. The system now uses enterprise database technologies with Geographical Information Systems capabilities to manage and relate these data streams into a common platform and allows access to the raw and interpreted data via web and desktop-based interactive tools, including interactive map and cross-sectional viewers and other graphical and tabular reporting tools. One of the primary benefits of this system is the neartransparent interaction that is possible with the Nashville District of USACE on the project. These techniques can now be effectively incorporated into systems that address the unique construction and data management tracking requirements for dams, dikes, and levees.IntroductionThe Center Hill Dam rehabilitation, as with other deep foundation installations, requires the contractor to collect a substantial amount of information over the course of the project, both for internal quality control of construction progress and methods, and for demonstrating compliance with owner specifications. This paper discusses techniques used at Center Hill Dam for consolidating, visualizing and analyzing construction and instrumentation data using relational database and Geographic Information Systems (GIS) technology, collectively referred to as an Information Management System (IMS).The remainder of this paper presents the needs and objectives of the IMS, the components and data flows involved, the capabilities and user interfaces of the systems, and the benefits for the end users."

Jan 1, 2017

By Garland Likins

The Texas Department of Transportation, now considering using Augered Cast-In-Place (ACIP) Piles (also known as Continuous-Flight-Auger or CFA Piles) in their foundations, awarded a research project to Professor Mike O'Neill at the University of Houston (UH) to study the advantages and potential difficulties with ACIP/CFA piles. ACIP/CFA piles were installed on three sites for UH; they had extra instrumentation and additional measurements by UH staff during installation which are beyond the scope of this paper. Independent visual logging of the pile was done by an experienced inspection firm. The main advantages of ACIP/CFA piles are their speed of installation and their economy. Potential savings are substantial. Disadvantages include an unknown structural condition of the shaft. Inspection is critical, but many simultaneous observations make accurate inspection difficult. Because of resulting uncertainty, many engineers have avoided ACIP/CFA piles in the past.

Jan 1, 1998

This paper summarizes seven years of Italian ex­perience with the use of large calibration chambers for the calibration, under closely controlled stress and strain conditions, of some in situ testing devices which are used in sand deposits. At the present time two calibration chambers are operating in Italy, one at E.N.E.L.-C.R.I.S. (Milan) (*) and the other at I.S.M.E.S. (Berga­mo) (**). Both chambers can accomodate cylindrical samples 1.2 m in diameter and 1.5 m in height. A detailed description of these chambers can be found in Bellotti, et. al (1982).

Jan 1, 1987

By Nagarajkumar BV

Pavai-and TeampT JV started working on the project T49A, Sumbar J & K State as part of slope and earth stabilization for ongoing Banihal - Katra Railway Connection Project. This project has several tunnels and bridges with slopes that are protected with various types of protection system such rock bolting, rock anchors, and micro piles. For the main two bridges Bring number 2 and 3 at T49 A location Pavai - TeampT JV has to design and execute the circular group of micro piles (Fig.1) for deep excavation of earth for the purpose of construction of well foundations (CAISSON FOUNDATIONS) for both bridge 2 and 3 piers. In this paper we discuss about the purpose, basic design, detailed design approaches and actual work implementation of micro pile with composite rock bolt applications and permanent rock anchors for slope stabilization works in this project.

Nov 1, 2022

By Emre Biringen

Over the past decades, there has been an increasing recognition of the strategic use of pile-supported rafts in design of heavily-loaded structures to reduce total and differential settlements. However, such a hybrid foundation construction method has not been widely utilized in many countries, including the U.S., due to code limitations. In current practice, the foundation design is based on either (i) the bearing capacity of the raft supported by the subgrade soils, or (ii) solely the pile capacity. This paper addresses the potential use of such hybrid piled-raft systems, where the structural load is shared by both by the piles and the subgrade soils directly beneath the raft, in foundation design of power plant structures. The study assessed some of the characteristics of piled-raft behavior by undertaking three-dimensional finite element analyses of two raft sizes, and various pile layout patterns, including the rafts with piles distributed evenly and only in the central area of the raft. The computer software PLAXIS 3D with the Mohr-Coulomb constitutive soil model was used to facilitate the modeling of such cases. The results presented in this paper indicate how strategically locating the piles could reduce the differential and total settlements.