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By Alan D. Fisher

Amtrak made a decision to replace an aging bascule bridge with a vertical lift bridge for their crossing of the Thames River in New London, Connecticut. The new lift bridge occupies the same alignment and shares the same foundations as the bascule span. During construction the deep foundation caisson supporting the bascule span settled and tilted. Investigation into possible reasons revealed interesting historical facts, both of the construction of the innovative open well caisson foundations and of the state-of-the-art in tremie concrete placing methods in use at the turn of the century. This paper describes both of these topics.

Jan 1, 2008

By Wesley Schmutzler

The Deep Mixing Method (DMM) was employed to raise and support the LPV (Lake Pontchartrain and Vicinity) -111 Levee in New Orleans. Even using innovative technologies, the tight schedule to achieve the 100 year elevation by June 1, 2011 was a daunting endeavor. The size and scope of DMM proposed for LPV-111 was on a scale never attempted outside of Japan. Over 1.65 million cubic yards of DMM was installed. LPV-111 is adjacent to the Bayou Sauvage Wildlife Refuge, which is the largest urban National Wildlife refuge in the United States. By utilizing DMM to control settlement and improve stability of the taller levee, side slopes were steepened from the conventional 1V:4H to 1V:2.85H, thus avoiding encroachment into the Bayou Sauvage and reducing the amount of clay needed for the completed levee. The COE utilized Early Contractor Involvement (ECI) for this contract. The ECI process allowed for input from the DMM contractor, TREVIICOS South, in order to optimize equipment resources and material requirements. This paper gives an overview of the extensive DMM requirements for LPV-111 and explains the benefits of the ECI process.

By Rachael M. Fischer, Daniel J. Woeste, Terence P. Holman

"A new 50 MW biomass renewable energy power plant was planned for construction in southwestern Georgia. The original foundation design consisted of very conservatively designed H-pile groups with vertical and battered piles to carry the axial and lateral loads. The authors conducted a testing program to value-engineer the foundations with the goals of increasing the working axial pile resistance and reducing or eliminating battered piles. Seven test piles were installed and dynamically monitored with a Pile Driving Analyzer (PDA). Two lateral load tests and one tension load test were conducted. The results of our testing program allowed the project team to: (i) increase working pile resistances by factors of 1.5 to 2, reducing the total number of piles by more than 30%, (ii) eliminate the battered piles, and (iii) lessen overall project risk. Poor communication and documentation in a critical area of the site required some piles to be spliced and re-driven after additional PDA testing, establishment of new driving criteria, and consideration of longterm soil setup. This case study emphasizes the economic and risk reduction benefits of a design phase testing program, and the need for consistent communication between parties in the field.INTRODUCTIONA new 50 MW biomass renewable energy power plant (Plant) was planned and constructed in southwestern Georgia. The Plant converts clean wood-based and paper-based waste from existing forestry and pulp operations, waste timber, and maintenance operations into steam that is used by an adjacent manufacturing facility. The Plant also generates electric power with limited greenhouse or particulate emissions for use by a local utility provider.The project site (Site) is located in Dougherty County, in the Coastal Plain physiographic province of Georgia; an area of known karstic activity. Specifically, the Site is underlain at depths of 30 to 45 ft by the Ocala Formation, a light-colored fossiliferous limestone of the Eocene era. According to Watson (1981), the Ocala Formation is 125 to 200 ft thick in the vicinity of the Site and increases in thickness to the southeast. Due to differential weathering, this formation is characterized by an irregular upper surface that transitions from sandy clay/clayey sand into a dense to very dense silt and fine sand locally referred to as limestone. This subsurface stratum is most relevant to the foundation design of the Plant."

Jan 1, 2016

By Wendy L. Mathieson

The Bonneville Power Administration (BPA) will build about 500 miles of new 500-kV transmission lines in the next 5 years. Many new lattice towers will be built in remote locations or in environmentally sensitive areas. Therefore, micropile foundations were designed that could be installed in remote areas, in variable subsurface conditions, and in a manner that would reduce excavation volumes and potential erosion concerns. Typical lattice tower foundation axial loads range between 75 and 1,500 kips (300 to 6,700 kilonewtons [kN]) per leg, with uplift loads being slightly less than compressive loads. Lateral loads range from 5 to 320 kips (20 to 1,400 kN) per leg. Full-scale axial and lateral load tests were conducted in geologically representative soil units during the micropile design for the 9-mile-long (14-kilometer [km]), Kangley-Echo Lake transmission line that extends through a protected watershed east of Seattle, Washington. Micropile foundations for single and double circuit suspension and dead end towers were designed using these load test data.

Jan 1, 2004

By Sanjeev Malhotra

"This paper presents the results of a pile installation monitoring and performance assessment program for pile foundations supporting 14 piers and 2 abutments of the 1700-ft long bridge crossing over a river in Baltimore, Maryland. Dynamic measurements were conducted during installation and restrike of 16 test piles, one at each support location. The foundation piles were 30-inch diameter, 0.75 inch thick pipe piles at the piers and 24-inch diameter, 0.5 inch thick at the abutments. The piles at the piers were approximately 100 ft long and were designed to carry 260 kips service load with a factor of safety of 2.25. The piles were driven open ended into a variable site stratigraphy containing recent deposits of organic clayey silts near the mudline followed by loose to medium dense sand, with some silt, and then by soil deposits from the Cretaceous period consisting primarily of dense to very dense, poorly to well graded sands and gravels and cobbles, with occasional seams of very hard to very stiff, low to moderate plasticity silts and clays. This paper presents the approach taken to evaluate the driven index piles and to develop criteria for driving production piles. It provides the Engineer with some data on pile driveability in Cretaceous soils in the Baltimore area, soil set-up effect, and an estimate of pile capacity.INTRODUCTIONThe typical approach to pile foundation design and construction should include an indicator pile program with dynamic measurements and a static load test program. However very often paucity of funds and schedule constraints cause an owner to do away with conventional static load testing which can take $25,000 to $100,000 and several weeks per test. This paper examines an alternate (though not equivalent) truncated approach to foundation assessment and presents a case history where this approach was implemented.Dynamic measurements were conducted during pile installation for the 14 piers and 2 abutments of the new 1700-ft long bridge over a river in Baltimore, Maryland. Strain transducers and accelerometers were attached to the pile top during initial driving and restrike of 16 pipe piles. The foundation piles consisted of 30-inch outside diameter, 0.75-inch thick pipe piles at the piers and 24-inch outside diameter, 0.5 inch thick at the abutments. The piles were driven open ended into a variable site stratigraphy. The approach taken to assess the foundation performance included 1) a pre-field wave equation driveability analyses, 2) field pile driving measurements, 3) post-field Case Pile Wave Equation Analyses (CAPWAP), and, 4) revised wave equation analyses based on field and CAPWAP data. The following sections describe in greater detail each of the steps taken to assess foundation performance and the results obtained."

Jan 1, 2005

By George Gazetas, Sissy Nikolaou, Fani Gelagoti, Irene Georgiou, Rallis Kourkoulis

"The need to shift geotechnical design from a “factor of safety” to a “performance based” design (PBD) approach has increased rapidly in the past years following examples from structural engineering. PBD supports sustainable engineered systems that target project-specific geotechnical behavior objectives and results in more rational and, in most cases, less conservative solutions. Resiliency, efficiency, risk optimization, and cost-effectiveness are key components of this approach. For design of retaining walls, the concept of mechanically stabilized earth (MSE) systems combines these attributes, while being environmentally friendly and adaptive to variable construction conditions. Natural hazards, such as earthquakes, may drive the design of MSE systems whose reliability depends on their performance under extreme events. In this paper, the authors compare the seismic response of an MSE steel-reinforced vs. concrete-reinforced retaining wall. The MSE system is composed of a grid of longitudinal and transverse ribs which internally enhances the capacity of the soil backfill. Results of fully non-linear twodimensional (2-D) numerical finite element analyses using two commercial programs with emphasis on the interface conditions are presented. The pull-out resistance of the grid used in the numerical simulation was evaluated from actual pull-out experiments. The results demonstrate a superior performance of the MSE system as compared to the concrete one, especially when subjected to strong seismic excitations.INTRODUCTIONThe idea of performance-based geotechnical engineering is not new, and has been evolving as our perception for ‘good’ performance has also evolved (Kramer, 2008). In early practice, the only criterion for achieving good performance was to avoid failure; designers had only to ensure that the available capacity of the geotechnical system is sufficiently higher than the expected demand (i.e. Load and Resistance Factor Methodologies). Yet, even when the key design requirements against collapse are satisfied, the system may still be placed into a condition in which the deformation constraints are not met (Bolton, 2012). To address these issues, geotechnical design has been developing into a predominantly performance-based approach that correlates deformation considerations to the severity of the experienced loading. As such, in earthquake-related problems, the definition of good performance of a geotechnical system is no more unique; for a low intensity earthquake the system should remain serviceable (i.e., the developed deformations should remain low), whilst for the design earthquake the maintenance of lifesafety is the single performance criterion."

Jan 1, 2016

By Axel J. Pollak

Since the late 1960's the Interstate Division for Baltimore City (IDBC) has been planning and developing the Interstate Highway System for the city to meet regional planning goals. The principal goals are to provide convenient access to the central business district and the port while diverting through traffic away from these congested areas. Interstate Route 95, an eight-lane highway carrying north-south traffic, has headed the city's priority list; during the 1970's its construction proceeded steadily from both east and west towards the harbor. Closing the final 8800-ft (2670-m) gap under the harbor will complete Interstate 95's construction. This final portion, known as the Ft. McHenry Tunnel project, will be built in nine construction contracts. Construction costs of the complete project are expected to exceed $700 million, making it the costliest single project in the Interstate Highway System. Full funding is being provided initially by the Federal Highway Administration (FHWA), and the Maryland Department of Transportation will re-pay the 10 percent local share from toll receipts within the first three years of operation.

Jan 1, 1989

By Sushant Upadhyaya, Deniz Karadeniz, Ahmed Mohamed

Soil setup analysis provides opportunities for efficiencies in pile foundation design and installation. Soil setup gain with time was evaluated as part of the foundation design and installation for twelve bridges along the Interstate 64 corridor between York County and Newport News in Virginia. The substructure elements of the bridges consist of driven precast prestressed concrete piles or H-piles. This case study describes lessons learned to understand the soil setup phenomenon during the installation of the piles in coastal plain. We were able to make expedited decisions during construction by analyzing previously performed pile dynamic analyzer (PDA) test results within the project alignment. Data evaluation included analyses of PDA data obtained from initial driving and restrike after a few hours to 5 weeks. The test data showed pile resistance increase up to twice in most cases and as high as four times in some cases. Foundation design and acceptance based on soil setup can provide opportunities for cost savings and advanced scheduling during construction.

By Akhila Manne, Prasad P. V S R

Storage tanks are heavily loaded thin-shelled structures that exert large loads on and require large foundations to support them. They are generally very sensitive to foundation settlements as it may hinder the performance of tanks resulting in significant commercial or social impacts. Selection of their foundation is dependent on availability of suitable ground and limitations imposed by design specifications. Design of the tank foundations is generally based on theoretical methods and validation by representative field tests. This paper reviews settlement criteria for storage tanks as per national and international standards, case studies of large to medium diameter tanks supported on deep foundation i.e., bored cast-in-situ piles and shallow foundations on improved ground and their performance during load tests & hydro-tests is discussed. Paper concludes that storage tanks can also be supported on shallow foundations resting on improved ground reducing the settlement, time and cost significantly depending on the sub-soil.

Nov 1, 2022

By Maurizio Siepi, Fabio Santillan, Lyndon Bedford, Carlo Crippa

"Abstract: Wolf Creek dam, on the Cumberland River in Kentucky, US, operated and maintained by the Nashville District of the USACE, is the Corps' largest reservoir east of the Mississippi river. The 1748 m (5,736 ft) long Wolf Creek dam combines earthfill and concrete gravity sections. Construction began in 1941 and was completed in 1950. The dam showed signs of instability in the 1960’s, and in the late 70’s an in-depth project of rehabilitation was undertaken, using both grouting and secant piles. The works saved the dam, but in the late 90’s further signs of distress worried the Nashville district of USACE which, after a study conducted on the water seepage, concluded that construction of a new concrete barrier cut-off wall was needed. In 2009, the $341.4 USD million contract was awarded to TREVIICOS-SOLETANCHE JV.The new wall, located upstream of the concrete monoliths, has a minimum thickness of 60 cm (24 in.), and runs the length of the embankment, into the right abutment, for about 4,200 feet. The founding depth reaches 84 m (275 feet), well below the zone of solutioning. With a total surface approaching 92,903 sq.m (1,000,000 sq.ft), the Wolf Creek barrier wall is unlike any other project in the world.The construction of the cut-off wall followed a complicated but logical sequence of several operations, involving a variety of technologies: grouting, hydromill, directional drilling, and secant piles with reverse circulation. The intensive rock grouting program was aimed to minimize the risk of slurry loss and extend the positive cut-off further deep. Subsequently, an Encasement Concrete wall was installed with hydromill, toeing into the rock, to protect the embankment during the following phases. Smart holes were then drilled into the Encasement wall down to the final depth. Eventually, the holes were used to install the secant piles by employing the reverse circulation piling method.An extensive verification campaign has confirmed the superior quality of the cutoff wall consisting of 1200 secant piles, exceeding by far USACE’s requirements. The main project was substantially completed in early 2013. A small portion of secant piles wall will be installed downstream of the dam, to close the switchyard, finishing the project in the early months of 2014.IntroductionWolf Creek Dam is located on the Cumberland River in south-central Kentucky. The Nashville District of USACE operates this multipurpose dam to provide hydropower, flood control, water supply, and water quality benefits for the Cumberland River system and surrounding region. Lake Cumberland, created by the dam, impounds 7,400 million cu.m (6 million acre foot) at its maximum pool elevation of 232 m (760 ft) above sea level. This lake is the largest reservoir east of the Mississippi and the ninth largest in the United States, and attracts 4.89 million visitors, more than Yellowstone National Park (2.87 million).This paper describes the recently completed works for the rehabilitation of the dam, accomplished by TreviICOS-Soletanche JV with the construction of a new Barrier Wall."

Jan 1, 2014

By R. G. Shen

The relation curve of strain and acceleration is presented in this paper. The steel pipe pile of 609.6 mm in external diameter driven by IDH-45 diesel motor hammer on the esturial shoal of Yangtze River. The ultimate bearing capacity of pile is analyzed by one dimensional wave equation and the effect of computational parameters of the equation is discussed.

Jan 1, 2010

By Sastry Putcha, Vamshi Vemula, Aneesh Goly, Kumar Allady

Current dynamic testing practice to obtain pile total capacity will not yield optimum capacity due to the strain incompatibility between the side and tip resistances during driving. Superposition of end of initial drive- static tip capacity and the peak static skin capacity during beginning of restrike and adding them is the preferred method. The FDOT method determines independent pile static tip and skin capacities in real time analyzing appropriate blows from the embedded tip and top data of the Embedded Data Collectors (EDC). This data is collected through a wireless radio transmitter, receiver, and laptop software. The approach utilizes EDC tip and top data and nonlinear single degree of freedom system to satisfy force and energy equilibrium with a global genetic inversion analysis. Top impacted energy equals at pile tip as sum of Static, Damping and Inertial energy providing independent tip resistance. With EDC sensors as boundary conditions, pile is divided into desired segments and using global inversion techniques one dimensional equation is solved for independent skin friction for every blow. EDC data compared close static load test results. The EDC - FDOT method has enabled cost effective 100% testing of driven piles cost effective. INTRODUCTION Historical documentation has shown that not only driven piles have a long history of usage but also continues to advance unceasingly till today. Historians placed the first pile driving using timber piles in the 4th century BC. While modern pile driving systematically started around nineteenth century, the credit for conceiving the idea of the applicability of wave equation to driven piles goes to David Victor Isaccs of Australia. His 1931publication “Concrete Pile Driving Formulae” provides the basis for modern pile driving using stress wave theory. He felt that the dynamic formulae then in use lacked the capability of detecting integrity and hence developed stress wave theory. This work was further developed starting in 1938 by W.H. Glanville and colleagues of British Building Research Board as they developed the first solution to the wave equation. But these early efforts have really taken off only with the advent of computers. E.A.L. Smith (1960) published ‘Pile Driving Analysis with the Wave Equation’ and provided first numerical solution to the wave equation. Within few years, the FHWA funded research and in due course this effort ushered the era of externally instrumented pile driving.

Jan 1, 2018

By Ganesh Kumar S.

"Soil reinforcement using stone columns is one of the well-developed ground improvement techniques for soft clay deposits. The load carrying capacity can be further improved by encasing it with geosynthetic material around the column which offers effective lateral confinement, prevents column contamination with improved drainage and strength characteristics. Improvement of undrained shear strength using vacuum consolidation is a type of hydraulic modification technique in which negative pore pressure will be developed which increases the effective stresses in soil without changing the total stress. The improvement in effective stress resulted in improved undrained shear strength of surrounding soil. In this research work, combined geosynthetic encased stone column and vacuum treatment method is examined for improving of extremely soft clay soils. The improvement in the time rate of consolidation and load carrying capacity of stone columns after vacuum treatment was studied using experimental investigations. It was observed that both load carrying capacity and stiffness of the encased stone column increased significantly with vacuum application. Also, application of vacuum accelerates rate of primary consolidation settlements. With this reduction in time, the construction activity can be accelerated which makes the project economically beneficial.INTRODUCTIONThe rising demand for the land for country’s infra-structure compels the engineers to work with even soft clay deposits which are not suitable for construction activities. As these soils have low bearing capacity and excessive settlement characteristics, ground improvement methods will be required before commencing construction. Among all available treatment methods, soil reinforcement and hydraulic modification technique are well-known popular techniques for its reduction in time required for consolidation settlement with improvement in load carrying capacity. When stone columns are used as a reinforcing member, it creates drainage with improves bearing capacity (Greenwood, 1970; Mitchell & Huber, 1983). However, the limitation includes lack of lateral confinement in very soft clay deposits, possibility of contamination, reduction in drainage path all which leads to the failure of stone columns (Mckenna et al, 1975). To overcome these limitations, encasement using geosynthetic material was adopted around the column which offers better lateral confinement, prevents intrusion of finer clay particle inside the column and provides effective drainage path with improved load bearing capacity characteristics (Van Impe, 1986; Raithel et al. 2005; Short et al. 2005; Borkemper et al. 2006; Murugesan & Rajagopal 2010; Kumar et al. 2014)"

Jan 1, 2017

By William M. Tanner, Daniel C. Brahana

"A drilled pier foundation was originally designed to support the proposed G. Wayne Clough Undergraduate Learning Commons on the campus of Georgia Tech in Atlanta, GA. Reflective of the site geology, the original drilled pier foundation was divided into a Northern and Southern portion with an allowable end bearing capacity of 60 ksf and 100 ksf, respectively. After initial pricing on the original design, several value engineering options were submitted that featured changes to the original design capacity and construction method. The project team selected the value engineering option that involved conducting an Osterberg Load Cell test to assess end bearing of the site bedrock and skin friction. Results of the Osterberg Load Cell test justified increasing the allowable end bearing capacity of the site bedrock to 100 ksf in the Northern portion and 125 ksf in the Southern portion. Considering the final foundation design and Osterberg Load Cell test program, a net savings of approximately $259,000, or approximately 34%, was obtained over the original design.Project BackgroundThe G. Wayne Clough Undergraduate Learning Commons (CULC) is a 5-story academic building on the Georgia Tech campus in Atlanta, Georgia. The CULC was completed in 2011 and consists of a concrete frame structure supported on a drilled pier foundation.After pricing of the original drilled pier foundation design, several value engineering (VE) analyses were performed by the foundation contractor in an effort to demonstrate the potential for a reduced foundation cost. The VE analyses focused on variations in design assumptions, as well as construction techniques. This paper presents a case study that demonstrates how the value engineering process can be used to reduce foundation costs.Site Investigation and Subsurface ConditionsThe CULC building site is located within the Southern Piedmont Physiographic Province, an area underlain by metamorphic and igneous rocks. McConnell and Abrams (1984) indicate that the site is located at the boundary between two distinct geologic formations. The Northern portion of the site is underlain by the Wahoo Creek Formation while the Southern portion of the site is underlain by the Stonewall Formation. The following paragraphs briefly describe the geotechnical investigations performed by the project geotechnical engineer (GE) for the CULC."

Jan 1, 2015

By Filippo Maria Leoni, George Filz, Wesley Schmutzler, Matteo Bertoni

"The US Army Corps of Engineers selected the Deep Mixing Method (DMM) for the required stabilization at the LPV 111 Project (New Orleans, USA). DMM was used for ground improvement/foundation strengthening and consequently to stabilize and support the burden of the new levee. Two different technologies were used: Trevi Turbo Mix (TTM) and Contrivance Innovation Cement Mixing Columns (CI-CMC). LPV 111 is the largest soil mixing project to date in the USA with its more than 18,000 elements installed to a depth of up to 67 feet for a total of 1.7 million cubic yards of treated soil. The preparation and execution of the project presented many challenges from various points of view. The little time available to complete the job led to the simultaneous utilization of eight deep mixing rigs and batch plants which worked 24 hours per day, 5.5 days per week on a stretch of land approximately 5.3 miles long. Given the imposing geographical extent of the project, a four phase laboratory programme and five field validation test programmes, conducted in as many different areas of the project, were completed to design and optimize the grout mixes and the installation parameters. The massive quality control/quality assurance testing programme produced over 500 drilled core holes and over 5,000 tested specimens in order to determine unconfined compressive strength (UCS) and uniformity of the DMM elements. This paper has the purposes of describing the tremendous challenges encountered and providing valuableinformation that may be useful for other future projects, including details not previously published.INTRODUCTIONReach LPV-111 is part of the Lake Pontchartrain and Vicinity Hurricane Protection System designed to protect the city of New Orleans and the surrounding areas from the surge that would accompany a 100 year hurricane event. LPV-111 measures approximately 8.5 km (5.3 miles) long, of which 7.2 (4.5 miles) extend along the north bank of the Gulf Intracoastal Waterway (GIWW) and the remaining 1.3 (0.8 miles) run north and terminates at the CSX Railroad Gate. The Bayou Sauvage National Wildlife Refuge borders the levee on both sides (Fig. 1)."

Jan 1, 2015

By John N. Cunningham

Despite the wide use of micropiles for rehabilitating and retrofitting existing structures, little is known regarding the load-transfer distribution of grouted micropiles in various soil deposits. The rehabilitation of a concrete-frame warehouse in Portland, Oregon, required provisions for the seismic restraint of a new shear wall; the installation of two micropiles was specified to meet project requirements. The micropiles were uncased, 19-m (63-ft) long, 200-mm (8-in) nominal diameter, and reinforced full-length with a 64-mm (No. 20) diameter hardened steel threadbar. Due to space limitations, a sacrificial, instrumented micropile was installed near the two production piles to verify design assumptions. This paper describes the geologic setting of the project within the unsaturated Missoula Flood deposits, instrumentation, load-displacement behavior, load transfer, and Beta-coefficients for the sacrificial micropile.

Jan 1, 2011

By William F. Starke

"The Ontario College of Art & Design (OCAD) located in Toronto, Ontario, found itself in dire need of space due to increased enrollment, leading them to embark on a major expansion and redevelopment on campus. The expansion entailed an additional 115,000 sq.ft. (10,700 m2) and a new major structure was required, as well as extensive redevelopment of existing buildings. The new Sharp Centre for Design was designed by acclaimed British Architect Will Alsop, of Alsop Architects, in a joint venture with Toronto-based Robbie/Young + Wright Architects. The OCAD campus is cramped for space and the design selected was a structure built over top of existing structures. The building has been described as resembling a “shoebox in the sky”, supported on raked columns transmitting high lateral forces as well as compression load to the foundations. There are 12 such supports, each supported by an individual caisson. In addition, the project entailed installation of other caissons in the courtyard area with the construction work accomplished under very confined conditions among the existing structures. The remarkable design for the new Ontario College of Arts will surely make it another of Toronto’s architectural landmarks. Several things make this project stand out as a unique deep foundations project.First is the architectural design. Words cannot do it justice: the picture is the only effective way to start to describe it. This is a big two-story box, built over the top of a fragile existing building. The underside of the box is 86 ft (26m) above street level. Students remained still inside the old building while construction was going on around and above them. There were serious concerns about vibration – not only its effects on the academic life; but more significantly, upon the stability and safety of the old building, which rests somewhat shakily on shallow spread footings.Steel stilts that look like toothpicks when scaled against the new and existing structures support the box. The stilts are much sturdier than they appear from the pictures, but it is easy to visualize the complexity of the loads they transfer to the foundations below."

Jan 1, 2004

By Mark R. Svinkin

Regulations are needed to keep construction vibrations in tolerable limits. The existing regulations were developed for low-rise residential structures, but they are incorrectly used for different super and underground structures. The existing regulations cannot prevent most of harmful vibration effects on sensitive devices, people and structures from construction and industrial vibration sources. It is important to determine the areas of application of the existing regulations and bring attention to the necessity of measurement of the structural responses for assessment of vibration effects on structures. For multi-story residential, commercial and industrial buildings, the frequency-independent safe limit of 51 mm/s (2 in./s) can be chosen for the peak particle velocity of structural, not ground, vibrations. Specifications for construction operations with dynamic sources have to consider specifics of each construction site. Preventive measures can be used to mitigate harmful vibration effects on various structures and settlements in sand and clay soils.

Jan 1, 2006

By Phil Wilkinson, Sam Whitaker

"The installation of large (XL) diameter monopiles offshore typically requires expensive and specialist plant, equipment and vessels. Due to the increasing size (weight, diameter and length) of the foundations, in order to mitigate installation risk, the use of large diameter drills is becoming an increasing requirement.Project developers often try to avoid drilling operations due to the time associated with the drilling process. This restricts projects in terms of location and it also overlooks the additional engineering benefits drilling can bring to monopile foundation design e.g. reduced foundation material and better fatigue design life.By comparing the lessons learned of three milestone overwater drilling projects; methods of maximising drill speed and decreasing drilling process time is established. Particular emphasis is put on pile internal relief drilling in a process known as Drive-Drill-Drive (DDD).The milestone overwater drilling projects are North Hoyle Offshore Wind Farm (OWF) (2003); Flamanville EPR cooling water outlet shaft (2008); and Gwynt-y-Mor OWF (2014).By evaluating the effect of foundation pile diameter on drilling process times, example foundation installation costs are derived and used to show that incorporating drilling as part of a process may not be cost prohibitive to projectsContinued advances in drill technology, and drilling rates of penetration, combined with an integrated approach to foundation design, challenge whether hammering only is always the optimal solution for XL monopile installation."

Jan 1, 2017

By Brian Wilson, Megan Atkinson, Richard Diggle, Nathan Sweeney

"Ruskin Dam, located near Mission, British Columbia, was constructed in 1929 and 1930 and comprises of a concrete gravity dam structure founded on bedrock. At the right abutment, which consists mostly of dense to very dense sands and silt, the dam abuts against overburden soils, and connects to a cutoff wall system consisting of sloping concrete slabs. Significant seepage and piping issues were encountered during first filling of the reservoir in 1930. In 2012, BC Hydro, the owner of the dam, awarded a contract for the construction of seepage control measures at the right abutment, including construction of a plastic concrete cut-off wall extending upstream of the dam, a plastic concrete seepage training wall extending downstream of the dam, tie-in of the new cutoff wall to the dam, consisting of jet grouting of the soils adjacent to the dam to allow for the construction of the special cutoff connecting the cutoff wall to the dam, and construction of additional jet-grouting ground improvement downstream of the dam.Integral to the upgrade was the requirement for the special tie-in cutoff wall, consisting of a highly flexible, impermeable membrane to connect the concrete dam to the new, 1 m thick plastic concrete cutoff wall. The tie-in extends vertically into bedrock through the dam and jet grout columns constructed adjacent and beneath the overhanging portion of the dam at the right abutment. The membrane is required to survive the anticipated earthquake induced deformation between the dam and the abutment soils.This paper describes the processes used to develop a material suitable to meet the specified flexibility and permeability criteria, as well as the innovative construction techniques utilized to construct the slot and place the bituminous material within it. The final dimensions of the slot were in the order of 7 m long by 25 m deep by 0.17 m wide. The bituminous material was placed under a head of water which was required to maintain stability of the slot, and was placed at temperatures in excess of 120 degrees Celsius."

Jan 1, 2017