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By Brian Wilson, John Scholte, Megan Atkinson

"In November 2004, the residents of the City of Nanaimo, B.C., Canada voted to approve a new conference centre as the centrepiece of a proposed revitalization project for the city’s historic downtown core. The proposal goal was to replace a cluster of derelict buildings with a dynamic and modern complex that would connect existing city facilities to a new conference facility, the Vancouver Island Conference Centre (VICC). The conference centre is expected to create 150 full-time jobs, attract visitors/ delegates from across North America and generate new economic opportunities for local businesses.However, the proposed site posed a number of geotechnical and geoenvironmental challenges. As is often the case with coastal cities, historic growth of the Nanaimo downtown and harbour area was achieved through reclamation of former waterfront areas and inlets. These areas were often infilled with random fills and even wastes, leaving a legacy of variable density heterogeneous fills contaminated with a variety of pollutants. Preliminary assessment of the site indicated a high likelihood of a requirement for deep foundations, a high risk of liquefaction in the event of an earthquake and the presence of both soil and groundwater contamination. Construction would be further complicated by the requirement for two levels of basement parking and the proximity of adjacent buildings and major roadways to the work area.With a limited budget (fixed by the referendum) and timeframe, the city needed a cost-effective solution to proceed with construction. A number of options were considered, but an innovative design using leading-edge Cutter Soil Mixer (CSM) technology best met the geotechnical and budgetary requirements of the site. The CSM approach also addressed the environmental concerns of contaminated soils and groundwater. Golder Associates Innovative Applications (GAIA) Inc., in association with the designers of their parent company Golder Associates Ltd. (Golder), proposed the CSM technology — at the time the first North American application."

Jan 1, 2008

By Nabil F. Ismael, Khalid Farraj

"The axial load transfer along large diameter bored piles in very dense silty sand was examined by field tests. Two instrumented piles 1.2 m diameter and with embedded length of 18 m and 25 m were load tested in axial compression to failure in connection with the construction of a big tower building in Kuwait City, Kuwait. Instrumentation included vibrating wire strain gages at various levels, displacement transducers and extensometers. The purpose being to measure the axial load distribution, skin friction, and base resistance at various load levels. In addition the settlement of the piles and the elastic compression were monitored. The ultimate pile capacity, side friction, and base resistance were determined and correlated with the Standard Penetration Resistance values as determined from the boreholes. Most of the load was transferred as side friction and the pile settlements at the maximum loads ranged from 1.6% to 2.2% of the pile diameter.INTRODUCTIONLarge diameter bored piles are used with increasing frequency for heavy structures in Kuwait and the Gulf region in calcareous sand. The behavior of short piles ranging in depth from 8 m to 15 m was examined by field test (Ismael 2012). However, larger diameter and deeper piles are being used more frequently, including the project described in this paper which included piles with 1.2 m diameter and 18 m to 25 m depth. The design of these piles requires knowledge of the skin friction and point resistance in these soils. While field tests on driven piles are available (Ismael 1989, Ismael 1999), field test data on long large diameter piles installed through very dense sands or silty sands are very limited at present. The results of two load tests carried out recently on instrumented bored piles at one site in downtown Kuwait City have become available. In these tests the failure load was extrapolated from the test results. It is important to examine and analyze the test results for the benefit of the geotechnical research and design engineers."

Jan 1, 2017

By Gerald Verbeek, Erick Baziw

Stone columns are used in geotechnical site remediation to increase load-bearing capacity and reduce settlement of foundations. Stone columns also improve slope stability and increase the shear strength of a soil. A very challenging problem is to characterize the in-situ shear wave velocities from data acquired from Downhole Seismic Testing (DST) after the insertion of stone columns. DST is an important geotechnical testing tool for site characterization that provides low strain (<10-5) in-situ interval compression and shear wave velocity estimates, but the postanalysis of seismic data acquired from DST in the presence of stone columns is very challenging due to the resulting complicated in-situ soil conditions. To obtain the right results it is necessary to use an algorithm that incorporates source wave raypath refraction. Starting with the Normal Moveout Seismic Cone Tomographic Testing (NMO-SCTT) algorithm developed some years ago, this paper outlines the modifications and additions made to this NMO-SCTT algorithm to facilitate stone column site characterization. To dramatically reduce the optimal solution space for the estimated interval velocities the paper also described a priori conditions that are applied based on the unique nature of the stone column site conditions.

By John P. Turner, Steven S. Dapp, Dan A. Brown

"The Goethals Bridge Replacement (GBR) spanning the Arthur Kill Waterway between Elizabeth, NJ and Staten Island, NY is supported on over 200 drilled shaft foundations ranging in diameter from 4.5 ft to 10 ft and socketed into Passaic Formation siltstone. Four drilled shafts, two on each side of the bridge (NJ and NY), were load tested using the bi-directional axial load method. Axial test results demonstrate that RQD, taken by itself, is not necessarily a reliable indicator of side or base resistance. High recovery with low RQD can be a function of horizontally bedded siltstone and shale where the individual pieces of core do not exceed four inches, but may still provide very high side and base resistance. Axial testing was followed by a lateral rapid-load test (Statnamic) on each of the same four shafts. In addition, one of the shafts was subjected to a static lateral load test to validate the rapid-load method as being representative of static loading conditions. Results of the axial load tests provide the basis of unit side and unit base resistances used in the LRFD design of the rock sockets for axial loading, while results of the static and Statnamic lateral load tests were used to calibrate p-y curve parameters used for design under lateral and moment loading. This paper describes implementation of the load testing program and its role in the design process.INTRODUCTIONDesign of drilled shaft foundations for the Goethals Bridge Replacement (GBR) required load testing in order to validate the parameters used for calculating geotechnical axial and lateral resistances. The bridge, including foundations, was designed in accordance with the AASHTO LRFD design specifications, 6th Edition (2012). The bridge owner is the Port Authority of New York and New Jersey (PANYNJ). One of the PANYNJ project requirements was stated as follows:“Perform a minimum of two (2) separate axial compression load tests (one [1] in New York and one [1] in New Jersey) for each demonstration shaft of different size and construction methodology to verify the design assumptions and construction procedures. At a minimum, one (1) demonstration shaft is required to be representative of production shafts with a diameter within one (1) foot above or below the demonstration shaft diameter.Conduct a minimum of two (2) lateral load tests (one [1] in New York and one [1] in New Jersey) for each demonstration shaft of different size and construction methodology. At a minimum, one (1) demonstration shaft is required to be representative of production shafts with a diameter within one (1) foot above or below the demonstration shaft diameter.”"

Jan 1, 2016

By Dharmil Patel, Michael J. Chow

"Construction progress is nearing completion at a Brownfield Site for a 100,000sf mixed-use 10 story building plus cellar for Silver Star Motors including a two-floor pre-owned Mercedes Benz showroom; high-end residential rental studios, 1, 2, and 3 bedroom apartments; and penthouses on the upper two floors. Excavation through impacted soil extended to 15ft depth. Project is approximately 7 ft north of a NYCT subway station, portions of the SOE are within inches of a 6ft diameter NYCDEP Sewer, and cellar extends below the depth of adjacent structures, requiring over 200 lf of underpinning.A complex series of earth retention systems was utilized consisting of underpinning, drilled-in soldier piles (micro-piles), timber/concrete lagging, soil anchors and inclined rakers supported by a partially constructed foundation mat. Foundation mat subgrade was approximately 4 ft below the groundwater level creating more challenges during underpinning and achieving suitable foundation subgrades. All construction was undertaken on a non-union basis.This paper describes the design, construction, and lessons learned for the multiple earth retention systems, Brownfield Remediation requirements, instrumentation, and monitoring used to manage complications of building adjacent to an active subway station, in close proximity to existing utilities, with underpinning and mat foundation installation below the water table.Results of the instrumentation program are summarized which utilized an AMTS, monitoring prisms on adjacent structures, automated seismographs, and manual NYCT surveys."

Jan 1, 2016

By Georgette Hlepas

How often phrases like these have been made by project managers and project teams trying to explain why there has been cost growth, project delays and differing site conditions claims. But does it really take x-ray vision? Do we really approach geotechnical construction projects unprepared for the subsurface that may be encountered because we can't get the answer? Too often our industry seems to think the answer is, "yes." However, this is not because we can't understand the subsurface. All too frequently it is because a choice is made to save money or time by foregoing or shortchanging upfront subsurface investigations. This is accepting a risk at the beginning of the process and realizing it during construction. Case histories have proven time and time again that upfront investment in site exploration and constructing a ground model mitigates risk in design and construction. But how much do we prepare? What level of investigation (or investment) is appropriate? The answer of course, is it depends; how much risk are you willing to take for your project and what are the potential consequences?

May 1, 2022

By A. Bozorgzadeh, B. M. Jensen, B. N. Koelling, B. R. Murtaugh

"The Service Base mooring system originally consisted of two general types of structures, 19 timber piles cabled together and steel three-legged pipe piles. The St. Louis District fleet moored to the fleet barges which were tied off to shore-side concrete deadman and supported on the landward side by the timber and steel piles. The purpose of this project was to replace the existing floating wharf mooring system at the St. Louis Service Base. The Marine Design Center of the U.S. Corps of Engineers developed a three pile cluster system concept. The clusters consisted of one vertical pile and two batter piles. Piles in rock sockets were selected to resist the uplift loads due to high wind loads on the tall, spare lock gates stored at the floating wharf. This paper focuses on the design of the rock sockets for steel pipe piles with large uplift loads and the lessons learned during the design and construction of this system.INTRODUCTIONBackgroundThe U.S. Army Corps of Engineers’ St. Louis District is located at the critical transition point on the Mississippi River where it is a “locking river” north of St. Louis and an “open river” to the south. The St. Louis District is responsible for maintaining navigation channels on the Mississippi River, the Illinois River and the Kaskaskia River. It is also responsible for the operation and maintenance of five locks and dams within its geographic boundaries.The St. Louis District utilizes a fleet of vessels (dredges, crane barges, motor vessels, and barges) to support the navigation mission identified above. The St. Louis District Service Base, located in St. Louis, Missouri, serves as the base of operations for the district fleet. This riverfront facility originally consisted of a floating wharf, a railroad trestle, and a walkway down the river bank to the floating wharf. Historically, there have been two fleeting areas at the Service Base. The main fleeting area was approximately 965 feet long and consisted of six fleet barges (Figure 1). This area supported the Dredge Potter and its attendant fleet. The upper fleeting area was approximately 1,050 feet long and consisted of various stop log, crane and work barges, dredge pipe pontoons and work flats."

Jan 1, 2017

By Stefan Larsson, Jan Ekström, Jennie Kock-Larsen, Håkan Garin

"This paper describes the testing procedure (or protocols) for quality control of dry deep mixing columns in a major ground improvement project carried out in Sweden. Quality control was mainly based on column penetration tests performed at different stages in the project and on two occasions after installation. In the paper, the results from the tests are compared with tests on the unimproved clay. As expected, the results show that the correlation between undrained shear strength in the columns and in the unimproved soft soil depends mainly on the in-situ stress. However, the correlation probably depends on when the tests were performed after mixing. When the influence of the in-situ stress was excluded from the analysis, no significant correlation could be identified. This means that the undrained shear strength in the columns and in the unimproved soft can be considered to be uncorrelated when the strengths and the corresponding variability are evaluated with depth from groups of tests.INTRODUCTIONQuality control and quality assessment of deep mixing (QC/QA) constitute a key component in verification of the limit state design. Due to the complex mixing process and varying geological conditions, it is normally not possible to sufficiently assess the strength and deformation properties in advance. In Sweden, the most commonly used QC/QA method for verification of the limit state is the column penetration test (Axelsson and Larsson 2003; Bergman et al. 2013). The method works well but is time-consuming and requires many tests since property variability is normally high. The column penetration test can be used to assess the undrained shear strength Cu,col. However, it is not clear how the strength correlates to the undrained shear strength of the unimproved soil Cu,soil. There are common factors such as the in-situ stress state and the natural water content, which makes a positive correlation probable, i.e. as Cu,soil decreases, Cu,col also decreases and vice versa. The unimproved soil has a natural spatial variability, but it is not known if the improved soil follows the same variation. The mixing process has a substantial influence on the strength variability and may supersede the influence of other factors. However, if a sufficiently good correlation exists between Cu,col and Cu,soil, information from the geotechnical ground investigations can be used in the design and planning of QC/QA of deep mixing in a more stringent manner. Information about the correlation is also essential in reliability based design, where a strong positive correlation may have a negative influence on reliability. However, as discussed by Al-Naqshabandy and Larsson (2013), this correlation may be weak or insignificant for a representative failure domain where the mixing process may have a dominant influence on the strength variability. It is thus of interest to assess the correlation."

Jan 1, 2015

By Joel Moskowitz, George J. Tamaro

"A new office complex is being constructed within 25m of the Hudson River in New Jersey. The project, about 140m by 100m, will include 4 basements under the entire footprint. The perimeter was to be secured by a 0.8m thick diaphragm wall, laterally supported by high capacity tieback anchors to rock. Columns were to be supported on footings or piers to rock at a nominal bearing pressure of 3.8MPa at depths up to 17m. Although some variation in rock quality was observed in borings, a substantial vertical seam of weathered and/or decomposed rock, 1 to 2 meters wide by as much as 8 meters deep, was encountered during construction necessitating field redesign. In some locations, the seam dipped below rock that is more competent. Footings were redesigned for support on drilled caissons, or soft rock was excavated and replaced with concrete necessitating a reduction in bearing pressure of the footings by one half. The tower covering the south half of the site was topped out in 2002 and the garage levels in the north half of the site were completed in 2003.PROJECT DESCRIPTIONIn September 1999, a major investment company began the due diligence process to evaluate a property on the shore of the Hudson River in Jersey City, New Jersey for a new multi-use complex. The site offers a spectacular view of lower Manhattan directly across the river from the site of the former World Trade Center. The site, covering two city blocks, was previously occupied by manufacturing and office facilities of Colgate-Palmolive.The building footprint is approximately 140m by 100m, the southern half of which is occupied by a 260m tall office tower, shown in Fig. 1. As of this writing, design of the structure for the northern half of the site has not been finalized, but it is expected to comprise an 11-story office building. A glass-covered atrium will occupy the street that formerly separated the two blocks. As part of the due diligence process and preliminary design evaluation, alternatives were considered to accommodate various numbers of parking places, both above and below existing grade. A major consideration for below grade parking is the proximity of the Hudson River some 25m east of the east building line."

Jan 1, 2004

By Victor Li, Joley Lam

"INTRODUCTIONJacked piles are piles that are pressed into the ground, usually by hydraulic jacks. For this reason, jacked piles are also known as pressed in piles. Jacked piles are mainly used for the following applications.• Underpinning worksJacked piles have been commonly used for strengthening the foundation of existing structures. In pressing the pile into the ground, the hydraulic jacks will jack against existing pile caps or ground beams that support the structure or against a steel frame connected to the floor slabs or structural walls of the structure. The self weight of the structure provides the reaction force for pile jacking. Jacked piles used for underpinning works usually have lower design ultimate capacities, typically less than 2000 kN (225 tons).• New foundationsJacked piles can be used to support new structures. A heavy pile jacking machine is employed to provide the reaction force for jacking the piles into the ground.• Retaining structuresJacked piles can be installed at close spacings to form a retaining wall. For relatively large and easily accessible sites, the piles can be installed using a conventional pile jacking machine. For sites that are smaller and are more difficult to access, a more compact patented equipment called the Silent-Piler developed by Giken Seisakusho Co. Ltd. in Japan can be used.Jacked piles have several distinct advantages. The vibration and noise induced during pile jacking are minimal. Jacked piles are 100 percent proof-tested to a load level equal to the maximum applied jacking force. The pile jacking machine can also be treated as mobile kentledge for static loading test. In this article, discussion will focus on jacked piles used for supporting new structures.HISTORICAL DEVELOPMENTThe People’s Republic of China (PRC) is perhaps one of the earliest countries in which jacked piles were used as new foundations. Jacked piles had been installed in the PRC since the 1960s. The capacities of jacked piling machines used in the country are usually in the range of 3000 to 6000kN (337 to 675 tons). High capacity jacking machines with a capacity of 9000 kN (1000 tons), presently used by the construction industry in Hong Kong, were also manufactured in the PRC. There are also plans to produce machines with a capacity exceeding 10000 kN (1125 tons). It was projected by Wang (1999) that jacked prestressed spun concrete piles would become one of the most popular pile types in the PRC in the 21st century."

Jan 1, 2004

By Amalia Giannakou

When designing structures in seismically active areas, foundations of critical structures are typically located away from known faults. Indeed many seismic codes prohibit construction in the immediate vicinity of seismically active faults establishing minimum setbacks from the faults. However, for long structures such as bridges, tunnels and pipelines, a fault maybe unavoidable, and fault rupture risk impossible to preclude. This paper presents a case study of a bridge foundation design that incorporates the consequences of fault deformations passing through the foundation. A series of site surveys were conducted to characterize the fault environment, and fault displacement hazard analyses were conducted to develop design displacement demands. Subsequently, numerical analyses were performed to evaluate the fault rupture-induced demands on a pier foundation in terms of displacements and rotations. Initially, analyses were performed that model the free field fault rupture propagation to the ground surface of the fault to ensure that the basic site characteristics are captured. Subsequently, the foundation elements were introduced in the model and the fault rupture is simulated again. The interaction and influence of the foundation on the fault rupture propagation is calculated, and the consequent demands and distortions of the foundation block provide a basis for structural engineers to design the bridge.

By F Debidin

The progressive rise of an H-pile during driving of an adjacent pile is described in this case history in which piles 15 to 18 m long were driven to end-bearing for the foundations for a 230 m long building. The use of a reaction beam-soil anchor system for compression load tests is discussed. The results of static load tests to determine pile capacity are compared with those obtained by the Pile Driving Analyzer and by theory. Unusual high temporary compressions were observed by field control staff. Proof testing was necessary to determine the need for restriking of some piles in which rise had occurred.

Jan 1, 2010

By Orestis Zarzouras, Amalia Giannakou, Jacob Chacko

"When designing structures in seismically active areas, foundations of critical structures are typically located away from known faults. Indeed many seismic codes prohibit construction in the immediate vicinity of seismically active faults establishing minimum setbacks from the faults. However, for long structures such as bridges, tunnels and pipelines, a fault maybe unavoidable, and fault rupture risk impossible to preclude. This paper presents a case study of a bridge foundation design that incorporates the consequences of fault deformations passing through the foundation. A series of site surveys were conducted to characterize the fault environment, and fault displacement hazard analyses were conducted to develop design displacement demands. Subsequently, numerical analyses were performed to evaluate the fault rupture-induced demands on a pier foundation in terms of displacements and rotations. Initially, analyses were performed that model the free field fault rupture propagation to the ground surface of the fault to ensure that the basic site characteristics are captured. Subsequently, the foundation elements were introduced in the model and the fault rupture is simulated again. The interaction and influence of the foundation on the fault rupture propagation is calculated, and the consequent demands and distortions of the foundation block provide a basis for structural engineers to design the bridge.IntroductionThe Izmit Bay bridge, a 3-km-long suspension bridge that crosses Izmit Bay in Turkey, is planned to be constructed in one of the most seismically active places in the world. The south approach structures for the Izmit Bay Bridge along the western side of the Hersek peninsula bring the bridge down from on the order of El. 60 meters at the South Anchorage to an elevated embankment approximately 1.3 km farther south (Figure 1). The south approach structures are located within a zone of secondary deformation around the primary trace of the North Anatolian Fault. The concept design team has developed a concept design for a “viaduct” structure that consists of 10 spans with lengths varying between 136 m and 100 m and two back spans one of 125 m, attached to the main bridge and the other of 74 m attached to the south embankment."

Jan 1, 2017

By Slav Tchepak

The King&apos;s Wharf development is located in Sydney&apos;s Darling Harbour area. The site was originally used for industrial maritime purposes, which over the years has been reduced to accommodating leisure craft only. The site has been filled with various materials, resulting in fill materials varying from soils, to concrete and rock fill. A prestigious new residential development at the site required piles to found in Sydney sandstone that occurred at depths ranging from 1 to 27m. The selection of appropriate pile types is discussed, as are details relating to the design and construction of cast insitu Omega piles and CFA piles. A number of issues needed to be addressed relating to the piling, including the design of the piles, the potential for liquefaction of the fill material due to earthquakes, penetration of the piles through the fill materials, installation of the piles to a satisfactory positional tolerance and pile performance. A number of piles were dynamically tested to prove pile performance and these results are presented and compared with design expectations. The project was successfully completed on time and budget, indicating the selection of pile types in the difficult ground conditions to be appropriate.

Jan 1, 2000

By Waddah Akili

At an offshore site along the Red Sea coast of Saudi Arabia, marine structures were supported on tubular steel piles driven into coral and coral contaminated sands and silts. Surprises and disappointments faced during the installation of the piled foundation were, to a large measure, due to inappropriate design methodology and absence of proper soil information. The paper describes the design evolution process, highlights the static pile test program conducted to verify design parameters, and amplifies the need to prepare for worst possible scenario when coral deposits are encountered. Despite corrections made to the design, based on site-specific insitu parameters (skin friction, end bearing) perceived from load tests conducted on site; the final design adopted overestimated capacities in over 50 percent of total piles driven. The paper describes the changes introduced to the design during the execution of the project, highlights the pile test program conducted to verify the design, and compares pile design penetration with actual penetration depth. The unpredictable and erratic pile behavior observed, ascertains the need for more appropriate pile design and installation guidelines for driven piles in coral and coral contaminated formations.

By Rick Deschamps

A reoccurring problem with support of excavations in urban areas involves the placement of external support components like anchors or nails in right-a-ways, subway and utility setbacks, in areas occupied by adjacent structures, and within the property of non cooperative neighbors. Such a situation occurred for a project in Arlington, Virginia, which ultimately resulted in the preliminary design of a large footing supported cantilever retaining wall that was extremely costly and impractical to build. An innovative design alternate consisting of a series of vertical concrete elements (VCEs) supported by post tensioned tiedowns was proposed to the General Contractor and accepted by the owner. The VCEs were designed to serve as the main structural elements for both the temporary support of excavation system and the permanent wall. The VCE?s were constructed using single bite diaphragm wall panels oriented perpendicular to the excavation face including a rebar cage and tremie concrete. Threaded inserts were placed within the rebar cage to attach the cast in place exterior wall. Overall stability and lateral movement of the VCEs were controlled by high capacity vertical anchors embedded within the VCE. A detailed instrumentation program was installed to monitor the movements of the VCEs with relation to the excavation depth. The paper present the project case history by discussing the design concepts of the VCE, the construction approaches used to install them, the construction challenges encountered, and the performance of the unique system.

Jan 1, 2008

By Marcel Bielefeld, Joost Bakker, Rob van Dorp

Pile load testing can be performed by a static, rapid or high strain dynamic (generally designated as dynamic) testing method. The static load test is often considered the “gold standard” of testing with the other methods merely ‘alternatives’. However, the rapid load test, as a quasi-static test, has all the positive elements of the static alternative: the direct measurement of loads and displacements. Moreover as stress wave phenomena have no influence, the interpretation of rapid load test results is more straightforward than that of dynamic testing, and also independent of the person performing the interpretation. This paper will explore the Rapid Load Testing method and illustrate the advantages and limitations through a case study in Rostock, Germany

May 1, 2022

By J. Erik Loehr, Minh Uong, Andrew Z. Boeckmann, Sarah G. Myers

"The University of Missouri performed a lateral load test program involving 32 drilled shaft load tests for the Missouri Department of Transportation (MoDOT). Tests were performed at two MoDOT geotechnical research sites, and all shafts were founded in shale. Shafts were instrumented to measure the displacement of the shaft head, and the structural response of each shaft was interpreted from strain gage data and from ShapeAccelArray (SAA) data. The SAA is a chain of rigid segments with sensors that use MEMS (microelectromechanical systems) technology to measure the tilt of each segment/joint. The measuring principle of the SAA is therefore similar to that of an inclinometer. The SAA device was placed in a casing installed in the center of each test shaft to provide a continuous record of deflection along the length of the shaft throughout each test.Bending moment profiles were calculated from strain gage data and from SAA data. Interpretation of bending moments from measurements of strain (via strain gages) and displacement (via SAA) is a nontrivial exercise, primarily because the bending stiffness, EI, is nonlinear and greatly influenced by concrete cracking, which is difficult to predict. The procedure used for this work predicted values of bending stiffness along the length of the shaft as a function of the bending curvature, which was interpreted from the SAA data. Values for bending stiffness as a function of curvature were computed using Ensoft LPile v2012. Bending moment profiles from SAA data were typically similar to those from strain gage data. The SAA bending moment profiles were often “noisier” than the strain gage bending moment profiles, but the SAA bending moment profiles had more data points since the SAA chain was continuous from the top to the bottom of each shaft."

Jan 1, 2017

By Michel Bustamante

The Arbre viaduct, 200 metres long, is the most important structure on the Belgian portion of the High Speed Train line between Paris and Brussels. The particular geotechnical conditions of the soil with carboniferous limestone affected by karstic phenomena, has prompted the designer to found the viaduct on systems of high capacity vertical and batter micropiles. The design of the working micropiles was validated by full scale tests performed on instrumented micropiles. The size of the structure and the deformation criteria to be met when HS trains are crossing the viaduct, together with the lack of references for such innovative structure, called for monitoring the movements of the piers as soon as the link was open to traffic. The authors report on the results of loading tests on micropiles and the results of settlement structure monitoring for a period of 4 years. Settlement of the foundation is estimated taking into account the group effect.

Jan 1, 2002

By Mark R. Svinkin

"Construction equipment and operations usually produce soil and structural vibrations which may harmfully affect various structures and also the content of buildings and houses. The level of structural vibrations depends on a number of factors such as characterized sources of vibrations, soil conditions, and susceptibility of structures. There are certain knowledge and experience for managing the effects of construction vibrations which require implementation of condition survey of structures, information on construction dynamic sources and soil conditions at a site, evaluation of possible vibration effects on structure, calculation of ground vibrations before construction, use mitigation measures to decrease vibrations, and a choice of appropriate vibration limits. The paper presents the application of known concepts for assessment of vibration effects on structures from bridge constructions.INTRODUCTIONVibrations producing by construction activities such as pile driving, dynamic compaction of loose soils, demolition work, heavy construction equipment and trucks can affect adjacent and remote structures. Vibration effects on structures, sensitive devices and processes may create significant practical problems. Legal actions are often required for solutions of vibration consequences. The level of construction vibrations depends on dynamic sources, soil conditions at a site in particularly availability of soils with settlement potential, distances from the sources, parameters of waves propagating at a site and susceptibility rating of adjacent and remote structures. It is likely that intolerable structural vibrations from direct vibration effects of impact pile driving and resonant floor vibrations from vibratory pile driving may be induced in adjacent structures to construction sites.Foundation settlements resulting from soil vibrations in loose soils usually occur in the proximity of dynamic sources, but it is important that dynamic settlement may happen at various distances from the source. There are such examples. First, Kaminetzky (1991) mentioned a case history of building settlements developed at a distance of about 305 m (1000 ft) away from a pile driving site. Foundations of the buildings were underpinned on piles down to the tip elevation of the new driven piles to prevent building settlements. Second, Lacy and Gould (1985) shows that the peak particle velocity (PPV) of 2.5 mm/s (0.1 in/s) of ground vibrations could trigger dynamic settlements at distances up to 30.5 m (100 ft) from driven piles."

Jan 1, 2016