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By Kevin Baumgartner, Steven Babcock

A landfill in Phoenix, AZ reached capacity and was graded over in the 1970s. The property was subdivided into lots in 2007 to create a business park. However, the challenging site conditions caused by the underlaying landfill put into question the feasibility of typical deep foundation systems. Several different foundation systems were evaluated to support the proposed development. The considered systems were: drilled concrete shaft, driven piles, drilled micropiles and helical piles. Soil stability, landfill decomposition, method of installation, flexibility of design, anticipated material, and equipment costs were considered. A system of helical piles with concrete pile caps and grade beams was selected. To mitigate unknown obstructions, holes were drilled through the landfill debris at pile locations and then backfilled with screened granular material. The helical piles were installed through these backfilled holes and advanced to bear in competent native material below the landfill. This method allowed for minimal disturbance of the landfill materials and provided a strong and adaptable foundation. Additional advantages of helical piles on this site include minimal installation vibration, no grout or concrete in the deep foundation, and capacity verification for each pile via torque correlation. Two load tests were performed to verify the design.

Sep 8, 2021

By Inc. Pile Dynamics, Daniel S. Belardo, Marcus Galvan, George Piscsalko

Soil nails are often utilized as a temporary or permanent earth retention technique for slope stabilization and for excavation retention for existing or new structures. Soils nails are generally advantageous as installation is relatively rapid and they can be installed beneath existing structures and where site access for equipment is limited. Due to the typically small cross-section of these elements, the inability to inspect the holes prior to grouting/concreting, and the various installation techniques utilized, quality control for assessing the integrity along the entire length is limited. Currently, quality assurance is conducted by load testing to verify the pull out capacity after installation. The load testing is typically done on a small percentage of the total number of soil nails. This paper will provide the results of a demonstration where the new Non-Destructive Test (NDT) method Thermal Integrity Profiling (TIP) was used to access the integrity of several soil nails along their entire lengths. This TIP method has been successfully used for several years to assess the integrity in drilled shafts and ACIP piles. The TIP method assesses the integrity across the entire cross-section and can identify regions where bulges, necks, and insufficient grout/concrete are present. TIP testing can also help assure that the contractor's installation methods are adequate and consistent for the intended design. For the project presented, instrumented Thermal Wire were affixed to the centered tension bars prior to placement in the excavated shafts. Temperature measurements were recorded from the hydration energy generated after grout/concrete placement, capturing the entire heating cycle. Manufactured defects were installed on the center bar at multiple locations. The results and conclusion will be discussed as well as recommendations for future use.

Jan 1, 2017

By Scott A. Walker, Gabriel J. Alcantar, Brian Zuckerman, Ramin Golesorkhi

"The stadium development consists of construction of a 68,500-seat, open-air NFL football stadium for the San Francisco 49ers. The main structure will consist of a 7-story above grade steel structure supported by over 3,000 piles. Berkel and Company Contractors, Inc. (Berkel) was selected as the design-build pile contractor who used their auger pressure grouted displacement (APGD) piles for this project. During an indicator pile installation and pile load test program, fifteen piles were tested to develop installation criteria to support demands of 150kips tension and 180 kips compression. Following the indicator pile program Berkel installed 3088 piles in 30 working days. Throughout pile installation data were collected with an automated data acquisition system (DAS). During pile installation field engineers from Treadwell & Rollo observed the pile installation as well as the real-time data from the DAS. Strategic staging and pre-production planning by Berkel along with consistent collaboration with the design team created an atmosphere for a successful and on schedule project completion.IntroductionThe new San Francisco 49ers Stadium in Santa Clara, California will be a 68,500-seat facility, a rendering of which is shown in Figure 1. The main structure will consist of a 7-story above grade steel structure supported by more than 3,000 piles. The north, east and south portions of the stadium are designed as an open seating bowl, while the western portion includes open seating at the lower levels and seven-story tower which houses over 150 suites.The stadium project includes the stadium structure, as well as elevated open pedestrian walkways, commercial community space, and three new pedestrian bridges spanning a nearby by creek. Sustainable designs and innovations such as a green roof, photovoltaic panels, a ground source geothermal system, stadium-wide Wi-Fi capability, and access to public transit are provided throughout the project. The stadium is designed as an open, light, and airy structure and is surrounded by an existing amusement park, office buildings, the Santa Clara Convention Center, and the training facility of the 49ers."

Jan 1, 2015

By Abid Adekunte

"In recent years, developers have had to deal with complexities associated with numerous cases of deep basement construction in built-up areas. Design and construction of deep excavation support systems in urbanised zones come with many technical challenges. Restricted working spaces often render the use of temporary struts as wall restraint systems unpopular, as working space needs to be maximised. Also, tie-back anchors are often inapplicable due to the existence of adjacent structures. Therefore, developing alternative restraint systems for deep basement structures in builtup areas is becoming increasingly important to the present day basement engineer.This paper is centred on the design, construction and monitoring of enabling works for deep basement structures on three sites in the United Kingdom and Republic of Ireland. Traditional tieback anchorage and propping systems were inapplicable on the sites. As alternatives, separate novel wall restraint systems were developed and adopted, to enable excavation on each of the three sites.Performances of the novel wall restraint systems, as well as the responses of adjacent structures were monitored. Numerical modelling and field monitoring results show the three alternative wall restraint systems to be safe and effective. The paper also highlights the advantages of the novel solutions over conventional methods.INTRODUCTIONRecently, deep basement structures have become popular components of urban building developments. As pointed out by Pearlman et al., 2004, this could be attributed to the inadequacy of surface parking spaces in urbanised zones, while underground parking facilities are also believed to improve both aesthetic and commercial qualities of urban structures.However, while the incorporation of basement structure into new urban development appeals to developers and architects, the engineering design and construction aspects of basement works typically come against a whole lot of complexities and challenges. As highlighted by Wong, 2002, engineering problems associated with basement construction in built-up areas are numerous, some of these include; complicated sub-soil conditions, dealing with excessive active pressures, complex temporary works, proximity of sensitive adjacent structures, high level hazards to construction workmen and surrounding community, inadequate working space, etc."

Jan 1, 2015

By Monica R. Garcia, Antonio Alberto S. Correia, Paulo J. Venda Oliveira

"The aim of this paper is to analyze the creep behavior of a Portuguese soft soil stabilized with binders in one-dimensional conditions, based on oedometer creep tests. The study focuses on the analysis of the effect of the binder content and binder type on the creep behavior of a stabilized soil. The results show that the best binder type for this soil, in terms of creep behavior, is composed of Portland cement and fly ash with a dry weight proportion of 75/25, as this promotes the development of secondary pozzolanic reactions. The results also show the decrease in the secondary compression index with the increment of the binder content, since it promotes an increase in the cementation bonds between soil particles. The general analysis of the results shows a clear dependence on C??and qu, until values of qu of 1500 kPa; after that this relationship is negligible.INTRODUCTIONThe geotechnical structures (such as embankments, dams and buildings) built on organic soils exhibit notable creep deformations, which increase the maintenance and exploitation costs and can even compromise their functioning. To attenuate the creep effects of the soft ground, some improvement techniques are frequently used, such as preloading or reinforcing the soil foundations with vertical rigid inclusions, like concrete piles, stone columns or deep mixing columns (DMCs). However, the installation of DMCs in the soft ground induces (via the arching effect) a transfer of stresses from the soft soil to the DMCs, which causes an increase in the creep settlement on the DMCs (Venda Oliveira et al. 2011).Notwithstanding the fact that the creep behavior of clays has been the object of several studies (Leroueil et al. 1985; Mesri and Castro 1987; among others), the study of the creep behavior of soil-binder admixtures has been practically ignored by the scientific community. The few studies on this theme have revealed that a stabilized soil’s creep behavior is dependent on: the type of binder (Venda Oliveira et al. 2013), the binder content (Correia 2011; Bobet et al. 2011; and Venda Oliveira et al. 2013), the stress level applied during the creep phase (Venda Oliveira et al. 2013), the organic matter content of the natural soil (Venda Oliveira et al. 2012; 2014), and the curing conditions (humidity, vertical stress applied during curing, and curing time) (Correia 2011; Venda Oliveira et al. 2012).The aim of this paper is to contribute to a better understanding of the creep behavior of a soil-binder admixture, by examining the results of oedometer creep tests. The study focuses on the analysis of the effect of the binder content and binder type on the creep behavior of a stabilized soil. Additionally, the creep behavior is correlated with the effective vertical yield stress and the unconfined compressive strength (UCS)."

Jan 1, 2015

By Konstantin G. Ashkinadze

The paper considers performance of piles supporting transient pipe anchors in heavy industrial pipelines. Events such as pump trips or opening and closing of large valves produce short-term dynamic pulses in the pipeline with variable spectral characteristics. Their magnitude is large enough to cause major damage to the pipeline and its anchors, which face horizontal impact loads amounting to hundreds of kN. Design of pile foundations supporting these anchors is often governed by limitation of deflection of the support to prevent overstressing pipeline connections and equipment nozzles. The maximum deflection does not always correspond to the largest load because the stiffness of the soil surrounding the piles heavily depends on the rate of loading. Faster actions encounter stiffer soil response while loads of smaller magnitude applied slowly may be more critical for the deflection time history of the anchor. A typical transient action has both high- and low-frequency harmonics, which makes the response complex. Using load rate-dependent p-y curves published in literature, the paper develops methods of analysis of pile foundations for transient anchors. Pile displacement amplitude – input frequency – natural frequency correlations and time histories of pile response are constructed for typical profiles of transient actions, considering nonlinear soil response to large horizontal loads.

Jan 1, 2016

By Jason Herron, Joseph Brown

The common couplings for joining sections of helical piles with an outside diameter of 6.625 inches and 8.625 inches are square on square, flange to flange, external pipe sleeve, internal pipe sleeve, and welded joint. Each coupling type has advantages and disadvantages in efficiency, capacity, installation, and economics of the installed pile. All these coupling types have been used in the helical pile market in North America for various applications and designs. Many of these applications require on-site testing, but test records are not typically shared with the helical pile industry. Due to the lack of information available for square on square and flange to flange couplings, testing was done to compare the efficiency of installation, load to deflection response, and torque to capacity ratios of external pipe sleeve, square on square, and flange to flange couplings. Field installations and tension tests were performed in non-cohesive (sand type) soil near Caseyville, IL and in cohesive (clay type) soil in Centralia, MO. The data collected during these tests included rotations per foot during installation, installation torque, applied pressure, and deflection. The results of this testing are analyzed and discussed within this paper. The results indicate that the square to square coupling is the most efficient of the designs tested, but this conclusion cannot be fully justified without further testing due to the variability in the data gathered and the small number of piles tested. INTRODUCTION A helical pile is typically assumed to be a medium-displacement pile when its outside diameter is between 4.5 inches and 8 inches and a high-displacement pile when its outside diameter is greater than 8 inches. A helical pile designer has multiple options when selecting a coupling type for medium- to high-displacement helical piles. Each type of coupling has advantages and disadvantages and must be analyzed on the bases of efficiency, capacity, installation, and economics of a project. Typical couplings that are chosen by designers include square on square, flange to flange, external pipe sleeve, internal pipe sleeve, and welded joint. A helical pile must transfer axial, lateral, bending moment, and torsional loads, and the coupling must be designed to effectively and efficiently transfer each type of load. During the installation of a helical pile, the rate of penetration and the disturbance of soil layers play a critical role in the efficiency and torque to capacity ratio (Kt) of the pile. It is common for a coupling to protrude beyond the outside diameter of the pipe section being used. This is necessary for the function of certain coupling types and can facilitate the connection of couplings. However, it causes increased soil disturbance and reduce the rate of penetration due to soil bearing against the protruding portion of the coupling. A helical pile designer typically will work to minimize the coupling protrusion and create a pile with optimal installation efficiency but may choose a design with lower installation efficiency if it offers sufficient economic advantage.

Jan 1, 2019

By Peter Faust

"The south access road to San Francisco’s Golden Gate Bridge, known as Doyle Drive or Presidio Parkway, needs to be replaced. Built in 1936, it is the primary highway and transit linkage through San Francisco between counties to the north and south. The roadway is tucked into the natural contours of the Presidio and the Golden Gate National Recreation Area, one of the nation’s largest urban parks.The old steel truss structure will be replaced by a new concrete cast-in-place bridge. The foundation design of the new bridge is based on drilled mono shafts below each bridge column. Most shafts required large diameter permanent steel casing installed under strict vibration limitations since several historic landmarks are near the project alignment. Malcolm Drilling decided to use the largest oscillator in the world to install the piles.The area occupied by the Presidio is generally hilly, sloping down northwards to San Francisco Bay. In the western half of the project route, two bluffs rise steeply to about 80 ft (25 m). The bluffs are separated by a valley 60 ft (18 m) deep and 1,500 ft (457 m) wide, which is spanned by the old and new bridge. Overburden soils in this valley are made up of artificial fill, slope debris, ravine fill and Colma Formation, a fine to medium-grained sand unit with clay beds. The Bay Muds encountered in the project area are typically soft clayey silts, becoming medium stiff with depth.The basement rocks underlying the overburden belong to the Franciscan Formation, described as shale, sandstone, serpentine and greywacke, it is extremely variable in hardness, fracturing and weathering. The material can vary from very hard to very soft, can be slightly to very intensely fractured and almost not weathered, to totally decomposed within relatively short distances both laterally and vertically. Rock strength can vary from too weak to be tested to serpentine layers with unconfined compressive strength of 15,000 psi (103MPa) or higher. Groundwater levels in the area are typically no more than 10 to 20 ft (3 to 6 m) below the ground surface."

Jan 1, 2012

By Tony Amis, Marco Barla, Alice Di Donna

"Energy geostructures are becoming an increasingly popular solution around the world for Developers looking to reduce CO2 and system running costs. Energy geostructures are geotechnical structures that provide both the important role of structural stability while also acting as a heat exchanger with the ground, enabling the supported buildings and or infrastructure to be heated and cooled using the principle of low enthalpy geothermal systems. The main advantage of this innovative technology with respect to standard geothermal plant is the reduction of the initial installation costs and construction schedule benefits, compared to installing conventional geothermal solutions, largely due to the additional use of structures which would be constructed in any case. However, it is important with respect to energy geostructures that additional aspects need careful consideration. For this very reason, several research studies have been carried out over the last decade on this subject and a number of real case studies have been monitored and analysed. The key difference with respect to conventional shallow geothermal systems are mainly related to the geometry, which is imposed by the geotechnical project, and the need to ensure that the primary structural role is always guaranteed. Special boundary conditions, the reduced depth, the influence of atmospheric external temperature can also play an important role for energy geostructures. They can affect, both energy efficiency and, the geotechnical behaviour because of the possible thermal induced mechanical effects. This paper presents a picture of the current situation regarding energy geostructures and their peculiar features, and collects available data to provide a reference framework. Data has been collected from literature and personal communications and then processed to provide easy-to-read charts useful for practical consultation at a glance. This paper provides, an indication of the distribution of such systems worldwide, their spread in time, and a global view of their actual efficiency from the structural, energy, economic and environmental point of view.1. IntroductionEnergy geostructures are becoming an increasingly popular consideration around the world. Energy geostructures are geotechnical structures with a dual role of providing structural stability and the ability to exchange heat with the ground, to provide low carbon heat and coolth to supporting and or adjacent buildings and infrastructure, using the principle of low enthalpy geothermal systems (Barla and Di Donna, 2016; Laloui and Di Donna, 2013). A closed circuit of high density polyethylene (HDPE) pipes is embedded in the concrete, and a heat carrier fluid circulates through them exchanging heat with the ground. The HDPE pipework circuit inside the geostructure is linked to one of the above buildings or infrastructure through a heat pump, which adapts the temperature of the circulating fluid to the heating (winter mode) and cooling (summer mode) needs. In this way, heat can be injected into the ground during summer and extracted from it during winter. In principle, all structures in contact with the ground can be used as energy geostructures. The first examples of energy geostructures date back to the eighties in Austria and were mainly piles and shallow foundations. A decade later, Henderson et al. (1999) reported on what would appear to be the first successful use of geothermal energy piles in the US, with loops incorporated into the foundation for a hotel in Geneva, New York. As was their use in this New York case history, the typical geothermal energy pile application is used in conjunction with additional closed loop boreholes to provide the required energy capacity for a structure. Interestingly the report concludes that the geothermal energy piles had a better heat transfer performance than the borehole field. The first energy walls appeared slightly later, while still today only a few experimental cas"

Jan 1, 2017

By Gerry Houlahan

"The 2015 Outstanding Project Award (OPA), which recognizes the superior work of DFI members, was awarded for the San Francisco- Oakland Bay Bridge New East Span. The award was presented to representatives from Caltrans and the T.Y. Lin International/Moffatt & Nichol Joint Venture at the DFI 40th Annual Conference on Deep Foundations in Oakland, Calif. A committee selected this project based on size, scope and challenges of the project; degree of innovation and ingenuity exercised; and the uniqueness of the solution to the difficulties of the job. A bridge across the bay between San Francisco and Oakland was proposed as early as 1872, but it took until November 12, 1936, until it became a reality. The bridge spans to the west of Yerba Buena Island were conventional suspension spans, while the east spans used a steel cantilever truss design and simple steel truss spans. This double-deck bridge served the Bay Area well until 1989. In that year, the magnitude 7.1 Loma Prieta earthquake damaged the East Span of the San Francisco-Oakland Bay Bridge. The resulting interruption to service across the bay demonstrated the vital role this bridge plays in the economic and life safety activities of the Bay Area. The project owner, California Department of Transportation (Caltrans), determined that the safest, most cost-effective solution was a total bridge replacement. The Engineer-of-Record, T.Y. Lin International/ Moffatt & Nichol Joint Venture, working closely with Caltrans, the Metropolitan Transportation Commission (MTC) and the California Transportation Commission (CTC), was charged with developing a comprehensive design strategy that met the project’s stringent criteria for seismic safety. These criteria included the new bridge’s designation as a regional Lifeline Structure that must open to emergency traffic shortly after the occurrence of a 1,500-year return period earthquake"

Jan 1, 2015

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

By Tsuda Wakaki, Naoki Takahashi, Natsuki Okuno, Hidenori Takahashi, Ikuo Towhata, Yoshiyuki Morikawa

"Deep mixing (DM) method has been increasingly employed as a countermeasure against subsoil liquefaction in recent years. Pile-type DM, however, is considered to have little effect as a liquefaction countermeasure, because the shear deformation of unimproved soil around the piles cannot be reduced. However, experimental results, which imply that shear deformation of unimproved soil around DM piles can be reduced, were reported. Furthermore, a new plane-arrangement of DM piles has been proposed to mitigate lateral flow induced by liquefaction. The DM piles in this arrangement confront the lateral flow in any direction, compared with the piles arranged in conventional pattern such as square and triangular arrangements. In this study, a series of dynamic centrifuge model tests was conducted to verify the lateral flow resistance of DM plies in the new arrangement. The results indicate that the DM plies can reduce the lateral flow of liquefied ground when the pile displacement and the pile head rotation are restricted. In addition, lateral load acting on DM pile from liquefied ground, which is required for design strength of the DM pile, was investigated.INTRODUCTIONDeep mixing (DM) method has been increasingly employed as a countermeasure against subsoil liquefaction in recent years. The solidified body formed by the deep mixing method is usually block or lattice shape, composed of solidified columns that overlap each other horizontally. Lattice-type solidification has been shown to be effective as a liquefaction countermeasure despite the presence of unimproved soil inside the lattice wall, because the shear deformation of the interior soil is restrained by the wall (Suzuki et al., 1989). On the other hand, it has been thought that pile-type DM cannot reduce shear deformation of unimproved soil around the piles, because the displacement of the pile is less restricted than that of the lattice wall. DM piles have been reported to have little effect as a liquefaction countermeasure, but to be superior in terms of construction cost and applicability around existing underground structures (Koga et al., 1986). However, there are experimental results implying that DM piles have reduced the shear deformation of unimproved soil and mitigated its liquefaction (Yasuda et al., 2003; Tanaka et al., 2003). Yamamoto et al. (2006) conducted dynamic analyses of ground improved with lattice- and pile-type DM. Their results showed that pile-type DM with an improvement ratio of more than 35% reduces excess pore water pressure generated by earthquakes. Furthermore, the new pile arrangement shown in Fig. 1(a) has been proposed to mitigate lateral flow induced by liquefaction. It was developed and has been verified using dynamic model testing in a 1 g field (Takahashi et al., 2010a; 2010b; 2013; Towhata et al., 2010, Morikawa et al., 2014). The DM piles in this configuration interrupt lateral flow in any direction, unlike those placed in square and triangular arrangements."

Jan 1, 2015

By Tsunenobu Nozaki

"Basically, the “Press-in Piling Method” was invented to eliminate construction nuisances, such as noise and vibration which have been serious unsolved problems for advancing societies over a long time. In the construction industry, piling works have been a major cause of noise and vibration, because most piling methods utilize dynamic load to install piles into the ground. The secret of the Press-in Piling Method is to utilize static loading to install pre-formed piles rather than dynamic load. The piles are hydraulically gripped and jacked into the ground by the special piling rig known as the “Silent Piler”. Therefore, the piles can form a robust and firm foundation, which is another advantage of the Press-in Piling Method.The Press-in Piling Mechanism and Implant Foundations The basis of the Press-in Piling Method is simple. The Pres-in Piling Machine installs a preformed displacement pile into the ground by static jacking force. The reaction for the Press-in Force is generated by gripping previously installed piles, which are called “Reaction Piles”. Due to this, the Press-in Piling Machine can produce a powerful piling force whilst only requiring minimal machine size.With the Press-in Piling Method, as piles are pressed into the ground, they are incorporated with the surrounding soils, which provides a large bearing capacity and passive horizontal resistance. These embedded foundations which are firmly anchored into the ground are known as “Implant Foundations”. Being embedded into the ground, the foundations are resilient and maintain their serviceability even in the worst credible design conditions."

Jan 1, 2015

By Dinesh Hinduja, Pérez: Miguel

"Large structures are generally exposed to dynamic and structural loading. They require usually either foundation connected to hard rock through sockets or driven foundations, which encounter boulders as well.In this regards drilling hard-rock sockets or boulder offshore or onshore can be a challenging job especially when deep foundations are mandatory. To overcome the challenge, specialized equipment like a Pile Top Drilling rig (PBAs) can be used, which have to be correctly set-up and operated in order to get its maximum drilling performance. High performance drilling with PBAs requires maximizing key elements of its operation. The configuration and management of the drill string components are important. The key elements are constant weight on bit which is done by adjusting ballast and managing thrust force; and selection of cutters and proper flowing discharge.The methodology is based on the experience from over 40 years of building and operating PBAs for different project applications. These applications include drilling offshore and onshore for:?Superstructures and buildings?Drilling platforms, barges and jack-ups?Harbours, jetties, dry docks and dolphins?Bridges, piers and causeways?Marine sewerage diffusers?Offshore wind farms?Dam rehabilitationMHWirth documented methodologies demonstrate that by using PBAs properly it is possible to improves performance of underwater drilling for hard-rock sockets and boulders which ultimately reduces project-cost.Background. There is a significant percentage of total project cost in structural foundations. Equipment capabilities and technics to drill shaft with rock-sockets and embedded boulders onshore and offshore are highly developed due to the dramatic equipment advancement and experience in the last 40 years. Formerly, driven piles accounted for the majority of foundations either onshore or offshore, following the experience of previous practice in the market. Nowadays, deep drilled foundations can be constructed to carry the load through the overburden down to the sound load carrying rock or soil.Scope and objectives. The overall objectives of this study are:?Synthesis information on current practices to drill shaft with rock-socket and/or embedded boulders onshore and offshore with Pile Top Drill Rigs?Identify the principal challenges evolving with practice?Provide suggestions for improvements in the construction of drilled shafts through proper operation of Pile Top Drill Rigs?Convey information through case studies and experiences"

Jan 1, 2015

By Jean Wehbe, Daniel C. Brahana

"This paper presents a case history of drilled pier construction for a new stadium in Atlanta, Georgia. The stadium structure is supported on several different foundation types, with the heaviest ""mega columns"" typically bearing on drilled pier supported mats. The project includes 141 drilled piers with design diameters of 5.5, 6 and 6.5 feet. The piers bear on bedrock at depths of 20 to 110 feet below the ground surface. Many of the piers included rock sockets with design lengths of 5 to 18 feet. A pre-production drilled pier load test program was completed including one Statnamic load test, two Osterberg Cell tests and two lateral load tests. Non-destructive testing (crosshole sonic logging and sonic integrity testing) were also performed during construction. Production pier installation with over 3800 linear feet of earth excavation and over 1350 linear feet of rock excavation was completed in a little over four months. The piers were installed using both the cased hole method and the slurry method. All cased holed required downhole inspection and slurry holes were initially inspected with a mini-SID device and subsequently by sounding. Advanced drilling equipment and tooling were used to meet the production requirements for the project. This paper reviews the highly variable soil and rock conditions encountered at the site, briefly presents the results of the load tests, and discusses pier installation procedures and the equipment used for installation. The paper also presents conclusions related to the installation and lessons learned.INTRODUCTIONWith the opening of AT&T Stadium in Dallas, a new era of stadium construction began in the U.S. The new age stadiums are larger and have more amenities than their predecessors. The new Atlanta Falcons stadium is no exception. Many of the new features, including Atlanta’s innovative retractable roof, result in extraordinary structural loads. The roof structure is supported by a series of mega columns that bear on eight large caps, six of which are drilled pier supported. Each of the pier caps contains between 8 and 16 drilled piers that bear in the underlying bedrock. The design pier diameters are 6 and 6.5 feet. Augercast piles were used to support two of the mega column caps. Drilled piers, augercast piles, aggregate piers and spread footings are used to support the more lightly loaded portions of the structure."

Jan 1, 2017

By Raymond E. Sandiford

"The redevelopment of the World Trade Center (WTC) provided an opportunity for the Port Authority of NY and NJ to complete a long sought underground connection between all of Lower Manhattan’s transit lines, the World Trade Center and the World Financial Center (WFC) (Figure 1). Creating this connection was a challenge because the WFC lies west of the heavily trafficked Route 9A, also known as West Street. The previous connection was a bridge that required pedestrians to make significant level and directional changes to navigate the crossing. The positioning and elevation of the Route 9A pedestrian tunnel was established to provide pedestrians with a clear, single level, climate controlled corridor from the new WTC Transit HUB to escalators leading into the WFC Winter Garden.As the most direct link to the WFC, tens of thousands of people a day will use the pedestrian corridor. To accommodate this large number of pedestrians and provide an obstruction free passage, the tunnel has a clear width of 50 ft (15.2 m). Although only 250 ft (76.2 m) long, that short length presented many technical challenges.Here I describe how the challenges were overcome during the construction. However, some of the truly problematic issues arose from coordinating the phasing of this project with adjacent construction activities at the WTC, the reconstruction of Route 9A, and the WFC’s redevelopment program. The limited access to the excavation areas and confined site logistics were further complicated by having to maintain six lanes of traffic on Route 9A at all times. The efforts were so intertwined that, well into the underpass construction, the Port Authority Construction Department decided to merge a portion of that work into the WFC redevelopment."

Jan 1, 2012

By Andreu J. Ferrero

Polyurethane and acrylate resins are routinely injected into soils to gain strength and control water flow. However, most published data regarding strength gain is derived from laboratory samples created under ideal conditions. This study endeavored to inject resins into full scale mock-ups that could then be excavated and tested to yield results comparable to actual field conditions. To achieve this goal, a large container was filled with a silty SAND (SM), as defined by the Unified Soil Classification System (USCS). The soil was moisture treated and compacted in lifts of 0.3m. PVC pipes installed in a diamond grid into the soil were used to inject polyurethane and acrylate resins. Dynamic cone penetrometer (DCP) tests were conducted on the polyurethane treated soils, the acrylate treated soils, and the baseline untreated soils in the container. Testing results will be correlated to SPTn and CBR values to evaluate increases in the soil strength parameters in the treated soils. Cored samples of polyurethane and acrylate treated soils will be tested in compression, shear, and triaxial. These laboratory test results will focus on material property gains for the treated soils, in comparison to standard values for similar soil types. Complete documentation of the soil type, compaction methods, injection methods, and testing performed have been documented and will be presented in the final paper.

By Jonathan G. Cannon

"This paper will describe dynamic pile testing conducted during installation of driven octagonal precast prestressed concrete piles used as the foundation for this bridge. The piles were long and hence spliced. A number of the piles showed damage near the splices and the damage location was near the ground surface so that the damage could be verified using visual inspection. The piles and splice configuration are still in use today without modification. Further WEAP driveability analysis has been conducted which demonstrates the effect of the splice on pile stresses and a likely failure mode. A slight modification is proposed to the splice that should prevent the damage on future projects.INTRODUCTIONThe bridge site is located on the Olympic Way, Route 41, about 20km north of the regional centre of Albury, NSW. For a long distance north of the site the Olympic Way ""shadows"" the main Melbourne to Sydney rail line and is located on the Western side and in close proximity. At the bridge site there was previously a sharp dog-leg in the road and a right angle level crossing with the road changing to the Eastern side of the rail line, eventually joining up with the Hume Highway, which in turn now becomes a ring-road through the eastern outskirts of Albury. The dog-leg and rail crossing had warning signs and bells, speed restrictions and rumble strips to warn approaching motorists to reduce speed. Site distance was exceptionally good.Approximately 2years before construction a group of five ""high spirited"" young men from the local area were driving south on the Olympic Way adjacent to a south-bound train. It is understood they interacted with the train crew for a period of time. Unfortunately the car and train collided at the level crossing and all of the young men were killed. There were outpourings of grief in the local community and a decision was made to replace the level crossing with a road-over-rail bridge.The bridge was highly skewed with two piers and two high level abutments with fill embankments on both approaches.GROUND CONDITIONSThe site is open grazing country with approximately level ground at the site with surrounding low hills. The geology was unremarkable with consistent stiff clays for a considerable depth.The design required driven precast prestressed pile foundations with the piles to be driven to a considerable depth.Hard driving with high tension stresses were evident from the start of driving and a variety of different pre-bore lengths were adopted in an attempt to minimise driving and potential for damage. At the abutments the pile locations were predrilled for at least the full embankment depth.PILESThe piles were 550mm octagonal prestressed concrete with the pier piles being single piece and the longer abutment piles being two-piece with a ""standard"" epoxy glued box splice. Pier piles and the initial length of the abutment piles were 24m. The add-on piece used at the abutments was 12m. Pile concrete was grade 50MPa."

Jan 1, 1900

By Zia Zafir

"Levees in the central valley of California are primarily for flood control purposes and thus are subjected to infrequent hydraulic loading. The primary concern for these levees is their instability due to through and under seepage. Primary seepage control measures are seepage cutoff walls and/or seepage berms. The cutoff walls primarily consist of soil-bentonite (SB) slurry walls. The seepage berm could be a drainage blanket to allow the seepage with controlled exit gradient or an impervious layer to provide enough cover to protect any adverse effects of seepage in terms of sand boils. Although, Sacramento is an area of moderate seismic activity, levees protecting urban areas require assessment for the potential instability due to liquefaction and associated vertical and lateral deformations. In certain cases, the seismic deformations of the levee may not compromise the stability of the levees, but they may cause damage to the seepage control measures. Depending on the nature and extent of the damage, the mitigation measures may require limited or full replacement of the seepage control measures. This paper will provide a systematic assessment of these different types of seepage control measures under vertical and lateral deformations due to liquefaction and lateral spreading under seismic loadings.INTRODUCTIONThere are two broad categories of levees in Central California: levees that are subjected to continuous hydraulic loading such as delta levees and are called frequently loaded levees (FLL) and flood control levees that are subjected to seasonal or infrequent hydraulic loading, called infrequently loaded levees (ILL). This paper will focus on the seismic response of ILL. The probability of ILL experiencing an earthquake at the time of the design flood is very low. Therefore, consequences of seismic failure of flood control levees are only significant in terms of response time required to restore the level of flood protection provided by the levee before the next flood season. An example for this restoration is the restoration of the Pajaro River levees in Santa Cruz, California after the 1989 Loma Prieta Earthquake. Nevertheless, failure of flood control levees due to a seismic event could result in loss of the entire levee and/or loss of freeboard. In addition, some of the seismic failure of ILL levees may result in loss of seepage control measures such as the soil-bentonite wall.The State of California State approved Senate Bill (SB) 5 in 2007 that mandates for 200-year flood protection to be the minimum level of protection for urban and urbanizing areas in Central California (Sacramento-San Joaquin Valley) by the year 2025. This legislation also requires that urban and urbanizing areas protected by Federal project levees cannot use adequate progress as a condition to approve development after 2025. SB 5 requires that the urban level of flood protection be consistent with criteria used or developed by DWR (Government Code § 65007(k)). To avoid delaying urgently needed flood protection, Urban Levee Design Criteria (ULDC, 2012) was developed."

Jan 1, 2016

By Jeff Starchuck, Harald Kullmann

"In 2005, an inspection showed that the Deception Bay Wharf in the Canadian Arctic was at the end of its service life. Although Deception Bay is closed with landfast ice up to 5 ft thick, shipping operations continue year-round, with additional voyages in the summer open-water season to supplement mine supplies. The rehabilitation scheme that allowed minimal interruptions to shipping involved concrete caissons cast on barges and an ingenious placing system.WorleyParsons Westmar of Vancouver, B.C., performed the inspection under contract to the owner, Xstrata Nickel, Montreal, Quebec. The wharf, on the coast of the Nunavik region of Quebec, was originally constructed in 1971 for an asbestos mine, and is now used to support Xstrata’s Raglan nickel mine, importing fuel for p o w e r g e n e r a t i o n a n d general mine supplies, and exporting nickel concentrate to smelters in the south. Emergency repairs were essential to allow operations to continue at the site, while the parties considered permanent rehabilitation options and secured funding. The repairs were done in the openwater seasons, and included reinforcing the failed interlocks above water level with steel patch plates and injection grouting of the cell fill below the port crane in 2005. In 2006, workers installed a circumferential belting system below water level.Westmar held critical planning sessions with the mine operation personnel to find ways to stretch the limits of the mine supplies and nickel storage facilities. In the end, the parties agreed to shut down construction activities four times during the ice-free season to allow access to the dock site.Westmar developed a plan that allowed mine operations to continue during construction, and Xstrata approved the plan and budget in September 2006, for execution in 2007. Rapid construction was essential. To accommodate the short construction season and maintain minimum levels of service for the mine, the work was radically different from conventional Arctic deep-sea port construction. Like the original Deception Bay Wharf, construction practice was to use steel sheet pile circular cells with the consequential heavy support services for the labour force. Construction duration was typically two seasons. The plan for Deception Bay was executable in one season based on a concrete caisson structure. Only a modest amount of schedule float was needed."

Jan 1, 2009