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By Douglas G. Baker, Jason K. Braund-Read, Megan R. Sheffer

"Mica Dam, owned by British Columbia Hydro, is an 820 ft high earthfill embankment dam that was completed in 1973. The dam consists of a thin central impervious till core supported by upstream and downstream compacted sand, gravel and cobble shell zones, founded on bedrock and valley bottom alluvium deposits. In 2012, a project was started to install new piezometric instrumentation within the dam’s foundation and downstream shell zone.Deep drilling in large embankment dams is very difficult and requires careful planning to select a methodology capable of reaching the target locations, while ensuring that no damage is done to the surrounding dam fill zones. At Mica Dam, the drilling could only be carried out from the Dam Crest and drillholes had to be carefully oriented to avoid intersecting any existing dam instrumentation. The drilling work therefore required angled drillholes, at depths of up to 855 ft, through heavily compacted sands, gravels and cobbles, and to significant depths below the standing water table.During the planning stages for the Project, in early 2013, the preferred drilling method was selected and a drilling contractor was engaged for the drilling work. Critical dam safety concerns were identified and addressed during the design stage of the Project with the drilling contractor, so that risk mitigation measures and response plans could be effectively developed.This paper explains how background information and prior drilling experience influenced the final design and implementation of the drilling techniques used in 2013 to successfully drill the deep holes and carry out the piezometer installations in Mica Dam. Drilling procedures, instrumentation design and installation methods, as well as risk mitigation measures, are discussed."

Jan 1, 2017

By Saba Mohan

This study presents results based on the Pile Installation Demonstration Project (PIDP) that was conducted as a part of the East Span San Francisco-Oakland Bay Bridge Seismic Safety Project. For the three full-scale pile installations, two different high-energy hydraulic hammers were selected for the installation. However, these hammers may not have sufficient energy to drive these large diameter piles at their ultimate capacity following long-term set-up. Nevertheless, these hammers were selected because, soil plug behavior, the generation of excess pore pressures and remolding of soil during driving were expected to reduce the shaft and end bearing resistance, and therefore reduce the energy required to drive these piles to design penetration. Data collected during continuous installation driving and after a series of re-strikes at different set-up times ranging from 1 to 33 days were used as input data for CAPWAP. These results were used to estimate the soil resistance along the pile length and at the toe of the pile, and the soil pile set-up behavior. Validity of the procedures used to predict the soil resistance to driving and predicted blow counts were verified with the field observed blow counts and the energy that was delivered to the pile. Based on combined CAPWAP analyses, the soil pile set-up with time was estimated and compared with results of other methods currently available in the literature for predicting the soil pile set-up rate.

Jan 1, 2002

By Dr. Anup Kumar Mandal, Partha Roy, Shuvranshu Kumar Rout, Dipak Mandal, Biswajit Das

Installation of a new scalping station with bunker, apron feeder, scalping screen, ramp -retaining wall and approach bridge was planned in an existing integrated complex of phosphate fertilizer at a remote place in West Africa. Rock phosphate ROM, transported from mines by a combination of 100 Ton and 150 Ton dumper, would be fed to a steel bunker having capacity of 180 m3. Different options were studied for retaining wall at the junction of ramp and approach bridge. Initially options with conventional RCC Retaining Wall, Gravity Retaining Wall with Precast Concrete Blocks and Reinforced Earth walls were studied. Option with Reinforced Earth was selected as this option was much more cost effective compared to other options. But real engineering challenges cropped up when competent execution contractors were not available nearby the site. To minimize the cost, an innovative option with Stepped Retaining wall was then studied. Geotechnical parameters of native soils, selected for the construction of the approach ramp were determined and it was found that with available poor geotechnical parameters of the native soils, design of stepped retaining wall would not be feasible with respect to available bearing capacity, subjected dead load, live load, operational load and earth pressure. A conscious effort was then made to make the design feasible by improving the geotechnical parameters of the retained earth of ramp near the retaining wall. In view of that, mix design with locally available materials like Silexite, Sand, Laterite, Gravel and Silt at different proportions was made and samples were tested in the laboratory to determine relevant geotechnical parameters. Based on the test results, a suitable mix was selected that had high shear strength, enhanced bearing capacity and improved coefficient of earth pressures. Design of stepped retaining wall was then made with the selected construction materials and construction completed. The plant was successfully commissioned in December. 2021.

Sep 1, 2022

By Amr Sallam, David Thompson, Moataz Hassan

"The Little Lake Harris (LLH) Bridge was constructed in 1951 to replace the eastwest County Road 48 Bridge connecting the towns of Howey-in-the-Hills and Astatula in Lake County, Florida, United States. The 78-span bridge carries two lanes of traffic, is 3,130 feet long, and 36.1 feet wide. The concrete deck is supported by steel I-girders carried by one row of 18-inch square precast concrete driven pile. In the late 1980's, slight settlements were observed in several bents. In 1990, Florida Department of Transportation (FDOT) initiated annual survey of deck elevations during bridge inspections to monitor settlement. Due to the slow nature and magnitude of settlement, substructure instability was not a major concern to the department. However, public concern over the settlement and rough ride of the bridge continued to rise. FDOT contracted Kisinger Campo & Associates Corp. (KCA) to provide the needed design to correct the dips in the riding surface and minimize future settlement. KCA's initial design was based on the concept of ""helper bents"" at the settled bents in order to restore the bridge to original elevation. Estimated construction cost for seven helper bents was about $3.3M. FDOT requested evaluating other alternatives to reduce the cost of the bridge restoration. KCA involved the geotechnical consultant, Terracon Consultants, Inc. (Terracon), to perform a peer review and provide an economical alternative solution. Jacking and shimming the bridge was determined to be both technically viable and economical with a total cost of less than $300K. The design was completed in March 2010 and construction was completed in February 2011. This paper provides an overview of the LLH Bridge history, summarizes the evolution of the design methodology including the findings of the geotechnical study and presents lessons learned during the design and construction of the project.INTRODUCTIONThe Safety and Preservation of the State Highway System is the top priority of the FDOT. Therefore, FDOT initiated a bridge management program that starts with conducting biennial safety inspections performed by Certified Bridge Inspectors (CBI). The inspection reports together with the CBI’s recommendations are reviewed by a registered Professional Engineer (PE) and work orders are issued with priority ranking depending on the severity of the bridge deficiencies. If the scope of work is considered beyond the in-house crews’ capability, the work is then included in a contract for and bid. LLH Bridge was a little different. It was initiated in direct response to number of complaints the FDOT District 5 Structures Maintenance Office (D5SMO) received regarding settlement of the Little Lake Harris Bridge."

Jan 1, 2015

By Jim Bruce

This paper presents details of a slope stabilization scheme built in late 2003 at a 16m-high railway embankment in southern Ontario, Canada. The owner, faced with continuing maintenance and safety issues arising from numerous nuisance slides, and residential neighbors in close proximity to the slope, sought new proposals to replace a previous recommendation to cut down all trees and undertake a deep soil nailing scheme. A non-reticulated micropile array with surface cap beam was proposed and built on the south side of the embankment with no tree removal required. A detailed FLAC analysis was completed, using multiple iterations to arrive at the eventual, optimized micropile depth and spacing. Analysis predicted an 18% increase in the factor of safety. Short term inclinometer monitoring and performance evaluations in the months since construction so far corroborate the prediction.

Jan 1, 2004

By Saba Mohan

For the three full-scale pile installations, two different high-energy hydraulic hammers were selected for the installation. However, these hammers may not have sufficient energy to drive these large diameter piles at their ultimate capacity following long-term set-up. Nevertheless, these hammers were selected because, soil plug behavior, the generation of excess pore pressures and remolding of soil during driving were expected to reduce the shaft and end bearing resistance, and therefore reduce the energy required to drive these piles to design penetration. Data collected during continuous installation driving and after a series of re-strikes at different set-up times ranging from 1 to 33 days were used as input data for CAPWAP analyses. These results were used to estimate the soil resistance along the pile length and at the toe of the pile, and the soil pile set-up behavior. Validity of the procedures used to predict the soil resistance to driving and predicted blow counts were verified with the field observed blow counts and the energy that was delivered to the pile. Based on combined CAPWAP analyses, the soil pile set-up with time was predicted.

Jan 1, 2002

By Jim Bruce, Naresh Gurpersaud

"The West Toronto Diamond project, under construction since 2006 and due to be complete in 2015, is a rail-to-rail grade separation project in the heart of urban Toronto. Once complete, a depressed corridor over 1000 metres long will take the CN tracks beneath the CPR tracks. An interlocking steel pile wall serves to retain ground and cut off groundwater. Remedial measures, constructed using jet grouting, were required at several locations within and behind the steel piles.At mechanical interlock joints damaged or suspected of being damaged, jet grouting was used to improve native soils on the retained side of the wall to reduce permeability of the soil mass in intimate contact with the joints to 10-7 cm/s. At a number of steel piles where groundwater and soil type combined to cause basal instability inside the pipes during the interim between excavation and concreting, jet grouting was used to construct temporary bottom seals. At locations near adjacent structures where the steel pile installation process resulted in disturbed ground on the retained side of the wall, jet grouting was used to strengthen and stabilize ground.This paper outlines the details of the various jet grouting applications, the respective testing programs implemented to demonstrate in situ permeability and strength of the soil-grout matrix, and performance of the constructed system.INTRODUCTIONThe West Toronto Diamond (WTD) is a junction of several railway lines, all intersecting at the same grade (Figure 1). A major grade separation project at this site commenced in 2006 and is scheduled to be completed in 2015. The whole of the work is comprised of multiple contracts, completed and/or ongoing, by different constructors. Once completed, a depressed corridor over 1000 metres long with over 23,500 m2 (face area) of retained earth will bring the CN tracks beneath the CPR tracks and eliminate a major bottleneck at the most heavily used rail crossing in Canada."

Jan 1, 2017

By Franz-Werner Gerressen

As alternative energy industries pick up speed internationally, and as government regulation and restriction limit the use of impact hammers due to environmental limitation from construction induced noise during pile driving operations, unconventional solutions for more complex offshore foundation installations have become a necessity. Manufacturers and equipment suppliers race to develop alternative techniques to accommodate for offshore foundation construction in various soil conditions and at greater water depth. The FLYDRILL, and the Seabed-Drill BSD are two innovative systems for the installation of offshore monopiles with reduced environmental impact

By Dan Brown

Improvements in construction equipment and techniques in recent years have made possible the use of drilled shaft foundations in diameters and lengths not previously considered practical or feasible. Many highway bridge and other structures are now routinely founded on drilled shafts which are 2.5 m to 3.0 m (8 to 12 feet) in diameter and extending over 60 m (200 feet) in depth below grade. There are unique challenges associated with constructing such large and deep cast-in-place foundations and engineers should be aware of the special needs associated with site investigation, construction specifications, material requirements, and quality assurance. This paper outlines a number of special considerations for these foundations, along with strategies that may be employed to improve the reliability and quality of large drilled shaft foundations.

Jan 1, 2008

By Racquel Nottingham, Marc Mastrantuono

Micropiles often provide a favourable solution for many deep foundation problems especially when significant site constraints such as confined construction sites or vibration limitations have been identified. Often the durability of buried steel elements are heavily scrutinized in order to effectively determine the rates of corrosion and methods to reduce this while still maintaining the structural integrity of the engineered solution. Practices such as sacrificial corrosion loss and the introduction of plastic sheaths have become the go-to methods of corrosion protection. Since the introduction of the micropile, other solutions have been developed, namely protection with an adequate grout encapsulation. This paper will explore corrosion protection of micropiles and the guidelines provided in the published codes and norms. Since few codes define the exact way to verify the durability of these micropiled structures, the existing data is presented and the analysis of grout encapsulation as an effective corrosion protection method is evaluated.

Oct 1, 2022

By Raffaella Granta

Mosul Dam is an earth fill dam located on the Tigris River, approximately 40 km (25 mi) northwest of Mosul, Iraq. The construction of the dam was completed in 1984. It is one of the largest multipurpose dams in the Middle East, and the largest dam in Iraq. The dam provides flood control, irrigation, power generation and water supply. At 113 m (371 ft) high and 3.65 km (2.3 mi) long, the reservoir has a storage capacity of 11.1 billion m3 (392 billion ft3) of water. The main hydroelectric power station has four turbines for an installed capacity of 750 MW. The discharge system includes two bottom-outlet tunnels of 10 m (33 ft) diameter, a five-gate service spillway and an emergency fuse plug spillway.

Oct 1, 2022

By Allen Cadden

The type of soil we had was a silty fine sand. It had been placed by hydraulic methods in 1904 so it was quite clean I would say less than 10% silt the rest of it was very loose sand. That I'm not certain, I've only done it on sandy soils but it would stand to reason that some sort of a number should apply because you are measuring the amount of work that you are doing to it so if the soil is fairly consistent over the site it should be able to generalize from there but I don't know for a fact that it works. Well, verifying to ourselves that this method actually worked because we weren't certain at first when we were doing it so then we would develop the numbers and then check the results.

Feb 10, 2003

By Michael Cianchetti, Nadir Ansari, Matthew Janes

"PROJECT DESCRIPTIONThe R C Harris Filtration Plant underwent an expansion to install an underground sludge treatment capability consisting of a series of underground tanks within stepped excavations 12m (39 ft) and 10m (33 ft) deep into compact, wet sands over stiff clays and clayey silts.Concerns regarding the original structure influenced designers to set the lateral deflection limit for the proximal front footing at 4mm (1/6 in), (0.03% excavation depth). The design-build team indicated at the time of tender that the movement criteria was unattainable using the tender design. Through extensive Fast Lagrangian Analysis on Continua (FLAC) and a novel construction geometry the design-build team crafted an alternative that produced significant savings over the original concept and met deflection concerns.GEOTECHNIQUEThe hillside site drops 14.5m (47.6 ft) over a distance of 53m (174 ft) between the existing Filter Building on the north and the Services Building on the south. The soils adjacent to the Filter Building consist of 6m (20 ft) of sandy fills, to the footing elevation, over compact sands and layered dense sands and silts to a depth of 10m (33 ft) below existing footing. Beneath the silts lies a 10m (33 ft) thick stiff clayey silt, 2m (6.6 ft) of sandy silt till (containing cobbles and boulders) and an artesian gravelly sand at a total depth of 30m (98.5 ft).The tender information was deemed inadequate to accurately determine soil parameters for a finite element analysis. As a result, the design-build team performed pre-tender Cone Penetrometer Testing (CPT), including dynamic analysis. The CPT data indicated stratigraphy consistent with the conventional bore hole exploration (SPT results) however, the CPT data provided consistently superior soil strengths. The CPT data indicated the sands and silts were dense to very dense throughout their full thickness. The clayey silts below the sands were found to have shear strengths in the 100 to 200 kPa (14.5 to 29 psi) range with an Over-Consolidation Ratio (OCR) ratio of 1.5 to 2. The dynamic analysis, while low strain, indicated very competent behavior with Young’s Modulus values in the 200 to 350 MPa (29,000 psi to 51,000 psi) range. The CPT derived shear moduli and OCR values were vital in determining the soil engineering parameters used for the FLAC analyses."

Jan 1, 2007

By K. J. Yang

Based on investigations and model tests combined with pile foundation on Code compilation of drydocks, we present this report to give informations against uplift pressure of piles beneath floor of drydock. In a same kind of soil, we have got comparative tests results with single pile and pile group, and the latter was performed at different spacings, different embedded depths and different number of piles in the group. Having analyzed through the results, there are some new understandings of regularity about failure mechanism and uplifting capacity of single pile and pile group, as well as optimum embedded depth of pile foundation. The results of research approach to measured values of full-scale and model tests at home and abroad, it has been placed into the Design Code of Drydock in China (1985), and can give a reference to design of pile foundation at sea and on land under uplift loading.

Jan 1, 2010

By Kevin Cunningham

"Litigation resulting from neighboring structures with settlement and/or lateral movement or improper pile design and faulty soils engineering analysis, are a multi-faceted opportunity for law firms. These types of claim scenarios are an attorney’s dream, and can obliterate a Deep Foundation Contractors profit and more importantly, can be avoided with a progressive approach to risk management in design and project management.The following (4) case studies will be examined and dissected to discern certain lessons learned for risk management solutions to avoid these deep foundation related challenges in the future.1) Pipe Flotation – Soil Conditions Not Anticipated in Specifications or Contract2) Easement Encroachment – Easement Dimensions Not Recognized Until Completion of Project3) Subjacent Lateral Support – Neighboring Structure Wooden Pile Unprotected Causing Structure to Settle4) Improper Pile Placement - Construction & Design Caused Retail Store to SettleSpecific Deep Foundation project challenges involving: buoyancy calculations regarding subsurface soil characteristics, design factors taking existing subsurface sewer line easements into account, structural instability as result of excavation causing exposure/heavy rainfall to existing wooden piles supporting adjoining building and improper pile location resulting from faulty pile design will be described with risk management recommendations to avoid these challenges in the future.From the very start of construction on any project deep foundation and excavating work poses numerous engineering and technical challenges for developers, contractors and engineers. Dealing with changing or hidden conditions is one of the most difficult challenges facing any contractor or engineer on a project. Relying on incomplete or inaccurate engineering reports is another common problem. Other challenges include dealing with technical errors or oversights that are deeply embedded in the project specifications or bid process.No matter what is the origin of the problem or how it manifests, deep foundation contractors, design professionals and engineers should be ever-mindful of good risk management practices that can prevent serious disputes that can result in costly litigation."

Jan 1, 2015

By Ahmed Elmekati, Frederick C. Rhyner, Steven R. Lowe

"The current phase of the Pacific Park development (formerly, Atlantic Yards) in Brooklyn involves constructing buildings on a platform over an existing LIRR rail yard. To preserve the maximum amount of space in the already congested yard and protect the yard which remains in service during construction, high capacity foundations are being designed well above previous capacities in the area. In addition to spread footings and small mats, various diameters of drilled piles are being used at design capacities ranging up to 600 tons. The piles are generally grouted at low pressure, up to about 50 psi. Load tests for various drilled elements, including piles, tiedowns and soil anchors, have confirmed allowable side resistance (bond) stresses in dense sand ranging from 20 to 30 psi. Testing with different rigs and operators has shown that down-the-hole hammers are feasible, but the installation techniques, types of equipment and size of the pile make a significant difference. The results show that more cost-effective foundations are possible when ample testing confirms expectations.I INTRODUCTIONThe Long Island Rail Road has operated a mainline on Atlantic Avenue since the 1800s, with a terminal at the intersection of Atlantic and Flatbush Avenues. In the early 1900s, the mainline was reconstructed in a cut and cover tunnel section. The LIRR’s Atlantic Yard was constructed circa 1908 to service the terminal. It was depressed about 25 feet below street grade to coincide with the LIRR’s mainline tunnel under Atlantic Avenue. Record drawings indicate that the gravity retaining walls lining the perimeter of the yard and other ancillary structures had been designed for an allowable bearing pressure of five tons per square foot (tsf). Perhaps by coincidence, the mat foundation for the tower of the Williamsburg Savings Bank was also designed for five tsf in 1929.Figure 1 shows a typical geologic section through the site. The geology and subsurface conditions in this part of Brooklyn consist of fill generally five to 20 feet deep underlain by dense to very dense sand and gravel; in places, with numerous cobbles and boulders which make pile installation challenging. The sand strata that are on the order of 150 to 200 feet thick were laid down by glaciers during the last ice age and have been heavily precompressed. The sand strata are underlain in places by remnants of the Cretaceous-era Raritan Clay formation and Fordham Gneiss bedrock. Because of this, the sand strata generally provide excellent support for shallow foundations and the allowable bearing of five tons per square foot is usually easily justified."

Jan 1, 2016

By William M. Camp

Construction-induced earthborn vibrations have long been recognized as a potential problem with respect to the constructed environment and various vibration criteria are in use to prevent damage. A special case of construction vibration control is the protection of early-age or ?green? concrete. Unlike limits for damage prevention to building stock, there is no rational, widely accepted limit for protection of early-age concrete. Numerous criteria have been proposed or reported in the literature and the most relevant and rational proposals are summarized herein. These findings are applied to a case history involving both bored and driven piles. Vibration measurements were made during pile driving activities and the vibration magnitude was evaluated with respect to the exposure of freshly-placed and curing concrete to the earthborn vibrations. The maximum vibration magnitude at the applicable distances from pile driving was on the order of 0.3 inches per second. Based on the most persuasive literature, threshold values of 0.8 inches per second or even 1 to 2 inches per second for the protection of green concrete appear to be well-supported. Consequently, it was concluded that the pile driving activities and bored pile construction could proceed simultaneously.

Jan 1, 2010

By Nabil F. Ismael

Load tests were carried out to examine the ultimate bearing capacity of short, large diameter bored piles in connection with the construction of a multistory building on the Arabian Gulf in Kuwait. Testing included 0.45 m, 1.0 m, and 1.2 m piles installed through loose sand into a bearing stratum consisting of very dense cemented sands. All tests were carried out to failure. The base resistance and shaft friction were calculated using the Meyerhof method for a layered soil profile. The method employs the standard penetration test N-values. The results indicate that the piles are end bearing piles with a great portion of the pile capacity due to base resistance. The mobilized skin friction is small. The calculated pile capacities were very close to the measured values with the maximum difference not exceeding 10%.

By Fabio Santillan, Michael F. Zoccola

"Wolf Creek Dam and Lake Cum berland in Russell County Kentucky is operated by the United States Army Corps of Engineers (USAGE) Nashville District It is a combination 3,940 ft long (1,200 m) non-zoned clay embankment, a maximum of 215 ft (65.5 m) above top of rock and 1,796 ft long (547 m) concrete gravity section. Built in the 1940s, the limestone beneath the embankment is characterized by an extensive interconnected network of solution feature; varying from fist size to largecaves.In 2005, studies conducted by the Nashville Distrect concluded that a new seepage cut-off wall was needed as the existing cut-off wall, installed in the 1970s, did not go deep enough and did not extend laterally far enough to intercept all major karst features The dam was classified as a ""Dam Safety Action Classification I (DSAC 1) – Urgent and Compelling,"" the highest risk under USAGE risk category rankings. Also in 2005, under a USAGE risk screening program of its entire dam portfolio, Wolf Creek was classified as a Dam Safety Action Classification 1-Urgent and Compelling, which put it in the highest category. In 2007, an Independent External Peer Review from outside USAGE, concluded there was compelling evidence that a piping failure mode had re-initiated and was in an ""advanced continuation"" stage of development.Impounding approximately 6 million acre-ft (7.4x102m3) of water at flood storage, Lake Cumberland is the largest reservoir east of the Mississippi River and ninth largest in the United States. Catastrophic failure would result in widespread flooding, Ices of life and economic losses in billions of dollars.In 2008, the Nashville District partnered with a joint venture between finns Treviicos and Soletanche (ISM through a ""Best Value"" contract to construct a new seepage barrier wall. This acquisition method was used in lieu of a low bid contract due to complexity of the work and dam safety concerns. It took advantage of the experience and innovation of contractors by soliciting technical proposals that were evaluated independent of cost. Those proposals deemed technically qualified and responsive then underwent a trade-off analysis between ccst and technical approach and a selection was made of the one deemed to give the best combination."

Jan 1, 2013

By Abid Adekunte

Traditionally, designers and contractors provide additional external supports to retaining walls through the use of tie-back anchors or braces. Both approaches are known to have their shortcomings; braces limit working space within excavation areas, while tie-backs are seldom used in built-up areas where intrusion into adjacent property of non-cooperative owners has to be avoided or in situations where sensitive structures exist behind the wall. This paper focuses on the design, construction and monitoring of deep excavation support systems on two separate projects located in different ground conditions in the Republic of Ireland. On both projects, conventional ground anchorage and propping were inapplicable. This led to the development and application of two different novel solutions on both projects. Methods of wall performance monitoring on both sites also differ. Wall monitoring results show these innovative methods to be safe and effective. Advantages of the novel solutions over traditional approaches are highlighted.

Jan 1, 2010