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By Julie Hampden, Tim Dardis, Per Reinhall

"Noise from impact pile driving can harm fish, marine mammals and other sensitive wildlife over large areas. Marine pile driving is highly regulated, and regulators require sound levels to be below certain thresholds to avoid harassment and injury to sensitive marine life. In many locations, timing restrictions, use of noise attenuation technologies and extensive monitoring for impacts to wildlife are also required. As a result, permitting can be laborious and time consuming, and project implementation and scheduling can be complicated. Underwater noise levels are measured with an underwater microphone (hydrophone), which converts noise pressure to voltage and is calibrated to express the noise pressure in Pascals (Pa). The pressure is often expressed using a logarithmic scale, in decibels (dB). Several specific metrics can be used to describe underwater noise. Three common metrics are the instantaneous peak sound pressure level (dBpeak), the root mean square pressure level (dBRMS) and the sound exposure level (dBSEL) referred to as the peak, RMS and SEL levels, respectively.During impact pile driving, the peak pressure represents the instantaneous maximum pressure, either overpressure or underpressure, observed during each pile strike. The RMS level is the square root of the mean of the square of the pressure during the duration of the impulse; it is the average pressure level of the pile strike from beginning to end. The cumulative SEL (SELcum) is calculated by summing the cumulative pressure squared and integrating over time of duration of the pile strike. SEL is used as an indication of the cumulative energy of a pile driving event, which may consist of one or many pile strikes.Regulatory agencies use these metrics to help characterize the noise pressure levels that can affect sensitive species. Some of the most frequently encountered biological thresholds in the Northwestern United States that are used by regulators to describe potential impacts to sensitive species are summarized in the following table. Agencies have defined thresholds for different types of injury, either hearing or bodily harm, and for temporary injury or disturbance."

Jan 1, 2017

By Harald Vogel, Johannes Lachenski, Friedemann Koetzel, Sebastian Schnell

In this paper, a digital subsoil approach, a work-in-progress, will be presented describing the transformation from a classical 2D to digital 3D thinking process in the design of geotechnical structures. Certain pitfalls as well as lessons learned are described, and the reader can understand that the digitalization process of the design of geotechnical structures is always a problem-focused approach by creating systems for certain processes rather than setting rules or regulations. Three project examples are presented. Two of the presented project examples feature a heterogeneous geology distribution and made it necessary for the design of the foundations to work with 3D subsoil and 3D calculation models. However, the digital 3D design process in the third project, an inner-city excavation pit, is driven by the complicated boundary conditions making it necessary to work in a parametric 3D design space. All projects have in common, that new processes had to be developed. The paper concludes with a flow chart describing the process of the elaborated digital subsoil approach.

May 1, 2022

By Brandon M. Robinson, Osman F. Besler, Dominik Gaechter

With the increase in population over the last decade, and anticipated population growth over the coming years, Norway is making significant investments in the Country’s infrastructure. Part of this investment in development starts with the Intercity development project in South-East Norway, which is the largest transport project in Norway. The Intercity Development project consists of 270 km (167 mi.) of new doubletrack rail, capable of train speeds reaching 250 km/h (155 mph). The new stations are centrally located in the major cities, in South-East Norway, to provide the benefit to as many citizens as possible. The goal of the project is to reduce the increase in traffic, which is coupled with an increase in population, and reduce the travel times between the cities. The Intercity Development Project has an anticipated completion date of 2034. The Sandbukta-Moss-Såstad (SMS) project, part of the Intercity development, includes 10 km (6.2 mi) of new double-track railway and is situated on the Østfold Line, near the city of Moss, Norway shown in Fig. 1. The 10 km SMS-section covers three open stretches and two tunnels, including 630 m (2,066 ft) substructure for double-track railways on the open line at Sandbukta. The Moss tunnel is a 1720 m (5,643 ft) long tunnel from Sandbukta to Moss center, including a 420 m (1,378 ft) long concrete culvert. The new Moss station includes an 800 m (2,625 ft) long station area. The Carlberg tunnel is a 2350 m (7,710 ft) long tunnel from Kleberget to Carlberg, including a 200 m (656 ft) long concrete culvert.

Sep 8, 2021

By Xavier Pita, Alexandre Pinto, António Cristovão, Rui Tomásio

"The cutter soil mixing technology was been applied in Portugal since the last seven years. The aim of this paper is to present the main design and execution criteria, related with both the cofferdam and foundations solutions, using soil-cement panels, reinforced with steel profiles, at the new Leixões Cruise Terminal, located at the Leixões Port, in Portugal. The Terminal building was built with one basement on a marine environment, over very difficult geological and geotechnical conditions, which demanded the use of some unusual and integrated geotechnical solutions. It is also pointed out the importance of the QC/QA, as well as the technical, economic and environmental advantages of the cutter soil mixing technique, comparing with same more conventional solutions.1 INTRODUCTIONThe construction of the new Cruise Terminal at Leixões, main gate of the Atlantic Ocean to the North of Portugal and Spain, as a consequence to the constant increase of the cruise traffic, was a challenge from both the geotechnical and structural point of views, mainly due to very difficult and unusual conditions, ranging from the geological and geotechnical scenario to the existent and under operation Leixões Port infrastructures, mainly the South break water, as well as the existent cruising boarding deck (Figure 1).According to the Terminal Project it was necessary to build one basement below the water table level, including several earth retaining structures in order to allow the excavation works on dry conditions leading to a global cofferdam effect. For this purpose soil - cement panels, using CSM technology, reinforced with steel profiles, micropiles (both for foundation and cut off effect) and the existent sheet piles were used. Also pointed out are the adopted special foundations of a very complex structure, including bored piles and micropiles (Figure 1)."

Jan 1, 2015

By Eric Lindquist, John Compagnone, Gabriel Carvajal

"Condon-Johnson & Associates, Inc. (CJA) with the assistance of design consultant, Brierley Associates, designed and installed a water tight shoring system utilizing several ground improvement techniques jointly. Prior to the installation of the shoring system, a test program consisting of the installation and testing of 7 jet grout columns; 1 soil mix panel; 7 soil anchors and 3 tie downs was performed to verify design assumptions. State-of-the-art quality control measures were employed throughout the project.The shoring system consisted of:•,Deep Soil Mixing (DSM) wall utilizing triple axis tooling to install overlapping columns along the perimeter of the proposed excavation to a treatment depth of 54 feet.•,Installation of steel piles in DSM to provide rigidity to the wall.•,Installation of a jet grout bottom seal, installed from surface to a depth of 58 feet below existing grade.•,Installation of 153 soil anchors, 1-1/4” diameter and 47’-6” length, to tie the jet grout bottom seal to the native soil below to resist hydrostatic uplift, installed from existing grade to a depth of 91 feet.•,Installation of walers and pipe struts for internal bracing•,Installation and stressing of 117 tie downs, 1” diameter and 16 ft length, to tie the pump station mat slab to the jet grout bottom seal, installed from inside the excavated pit.Subsurface conditions at the site consist of uncontrolled fill materials to a depth of 20 feet comprised of sandy silt and clayey sand. The native soils underlying the fill generally consist of soft and compressible lean clay and silt with varying amounts of sands to a depth ranging from approximately 44 to 54 feet below ground surface, which in turn are underlain by dense to very dense silty sand. The groundwater elevation at the site is approximately 8 feet below ground surface.This paper covers the design aspects, construction, and quality control measures undertaken by the geotechnical contractor, with supporting figures.INTRODUCTIONThe owner, County Sanitation District No. 2 of Los Angeles County, designed upgrades to their existing Long Beach Main Pumping Plant Facility. The upgrades consist of a new pump station that includes a reinforced concrete below-grade wet well and dry well, a two-story operations building, two 78-inch diameter pipe inlets, two 42-inch diameter discharge pipelines connecting the existing manifold, two pipe junction structures, two insert-type junction structures, and electrical transformers. This paper focuses on the excavation shoring for the new pump station. The original shoring design concept for the pump station excavation illustrated on the contract plans consisted of pressed in sheet piles, a jet grouted bottom seal with soil anchors, 2 levels of internal bracing, and tie-down anchors to resist hydraulic uplift forces on the buried pump station."

Jan 1, 2017

By Nick M. Withers, Suthagarann Visvalingam, Cillian Mc Colgan

The level crossings removal project in Victoria is removing 75 level crossings across Melbourne to improve safety by separating trains from traffic, with other benefits such as reduced congestion, an upgraded road network, connected communities and support of urban regeneration. The level crossing at Station Street in Carrum forms part of the scope being delivered by the Southern Program Alliance (SPA), which is delivering level crossing removal works associated with the Frankston Train Line. At Station Street, a rail viaduct consisting of 19 spans and totalling approximately 545 m in length is under construction to remove the former level crossing. The viaduct consists of two parallel reinforced concrete Utrough girders and steel trough girders, one for each rail line. The foundations of the rail viaduct are founded on groups of Continuous Flight Auger (CFA) piles. The characterisation of geological units encountered at Carrum for the foundation design has been based on insitu testing and interpretation of test results from high strain dynamic pile testing (PDA) and Case Pile Wave Analysis Program (CAPWAP) from the Seaford Road Bridge, located approximately three kilometres South of Carrum, in similar ground conditions. By conducting pile load-deformation analyses based on pile testing significant savings were made for the client compared to the original design which was based on more traditional empirical correlations. This paper discusses the pile design methodology adopted using pile test data for this viaduct foundation. The results of this assessment are also compared to existing empirical correlations, and the limitations are discussed. The performance of the adopted pile design methodology using pile test data at Carrum rail viaduct is also discussed.

Nov 1, 2022

By Arpana P. Sabu, Themis Vaxevanis, Sissy Nikolaou, Guillermo Diaz-Fanas

Geo-failures from extreme events (landslides, wild fires, earthquakes, floods, etc.) have increased exponentially in recent years around the world and within the USA. When catastrophic failures occur, they usually involve hundreds of fatalities especially in cases of unexpected triggering events, such as large intensity earthquakes or heavy flash floods. Protective actions against identified potential geohazards can mitigate the associated risks and the future occurrences and prevent these occurrences from becoming disasters, targeting the essence of resilience in geotechnical engineering. Imaging and other virtual design and construction tools can be used to identify weaknesses that trigger geohazards and can, in combination with numerical simulations, guide decision making. In spatially distributed problems, 3D visualization and LiDAR-type of technologies are essential in providing geotechnical engineers a deeper understanding of precarious soil zones and support finding appropriate solutions. This paper will present the value of using virtual design and construction technologies though the case study of the Iztapalapa suburb of Mexico, about 20 km southeast of Mexico City. Iztapalapa was developed within irregular topography and has a long history of severe soil subsidence. Following the 2017 Puebla-Morelos earthquake, the town experienced large settlements resulting in extensive damage to the already frail buildings and unregulated infrastructure. The soil subsidence was visualized by mapping available historic and geotechnical data. The visualization helped to identify areas where additional investigations were needed. Additionally, this paper presents a case study of a series of landslides from the 2016 Mw7.8 Muisne Ecuador Earthquake, which demonstrates the advantages of using novel technologies to collect data and create cloud datasets from drones and digital photos to understand and evaluate geo-vulnerabilities in anticipation of an extreme event and during rapid reconnaissance to plan for long-term instrumentation, which can enhance geo-disaster prevention and overall community resilience. INTRODUCTION Iztapalapa is a southeastern borough of Mexico City (CDMX) located within the Mexico Basin (Figure 1). This borough is a densely populated area of CDMX with a total of 1.8 million inhabitants, and has a third of its population living in poverty (Gonzalez-Hernandez et al., 2015) with limited to no access to clean drinking water. Iztapalapa also suffers from high rates of crime, drug trafficking, sex trade and illegal buildings. As the population continues to grow, the already non-regulated and fatigued infrastructure is unable to meet the community needs, especially during and after natural hazard occurrences. The region of CDMX is one of the world’s most seismically active regions that is also exposed to other geo-hazards such as floods, volcanic eruptions, and continuous settlement due to water pumping that has reached 11 meters over the past 100 years (Nikolaou et al, 2019). While the soil subsidence alone has caused significant infrastructure damage in Iztapalapa and throughout the rest of the city, recent earthquakes have also contributed to those damages.

Jan 1, 2019

By Douglas R. Hardin, Stanley L. Worst, Joanna Mason

A challenging earth retention project presented itself in Washington, DC in the backyard of the historic House of the Temple (The Scottish Rite of Freemasonry, Supreme Council 33°). Located at 15th St NW and S St NW, a forty-foot-deep underground basement was to be installed adjacent to the existing Temple, a historic Carriage House structure dating back to the 1800’s and across a narrow alley from a four-story brick apartment building. The unique geology of the site included typical urban fill overlying a mixture of loose alluvial soils underlaid by dense marine deposits of the Potomac Formation. The clay, sand and gravel of the Potomac included nested boulders up to three feet in diameter. Design of the earth retention system accounted for ground conditions, installation methods and estimated movement of the system and adjacent structures. Anticipated ground water and unanticipated water from leaky sewers also proved obstacles to overcome during construction. Soldier beams were installed using a variable momentvibratory hammer to minimize disturbance to the historic and sensitive structures. Monitoring of the existing structures included both seismograph and optical targets during installation of soldier beams and as the excavation progressed. Micropiles drilled into the Potomac Formation were a part of the permanent foundation for the new structure. This local case history will delve into the details of the successful design, installation, and performance of an earth retention system and micropiles in a historic and highly congested urban environment.

Oct 1, 2022

By Masahiko Yamaki, Takahiro Yamanashi, Hijiri Hashimoto, Hirochika Hayashi

"In this study, the authors used heat conduction analysis with the aim of quantitatively evaluating whether treating improved ground with cover soil is an effective measure for maintaining strength development in the surface layer of improved ground after constructing cement treated soil for the winter season. This report describes a simple procedure to evaluate covering soil thickness, which is necessary for the strength of the surface of cement treated soil, by using the freeze index and both the water content ratio and dry density.INTRODUCTIONIt was reported that when ground improvement using cement is performed in winter in a snowy cold region (Fig. 1 photo, Fig. 2), the uppermost 1 m of the improved ground (i.e., the cement-treated soil) tends to become prone to solidification failure from exposure to the cold air during curing (Hashimoto et al. 2006). In light of this, our research laboratory conducted unconfined compression tests using curing temperature as a parameter of analysis on improved ground toward understanding the influence of curing temperature (ambient air temperature) on the strength improvement afforded by ground improvement.The authors found that if the curing temperature is maintained at 0°C for the first 28 days after improvement and then at 5°C for the next 337 days after improvement, the improved ground is expected to have 90% of the unconfined compressive strength of improved ground whose temperature was maintained at 20°C for the first 365 days after improvement (Hashimoto et al. 2011)."

Jan 1, 2015

By Rimas Veitas, James Panton, Erich Steinlechner

"Ductile Iron Piles (DIPs) are a proven, viable alternative to conventional piles, and for the past five years have been successfully used throughout New England. The installation process of DIPs lends itself to both large and small projects. Because of their installation efficiency they provide a substantial cost savings over drilled micro piles. Several New England projects (both end bearing and friction) will be evaluated, focusing on the installation and design procedures.BackgroundThe driven ductile cast iron pile (DIP) is a simple, fast and highly effective pile system. Over the last 30 years over 10 million feet of this pile system has been installed worldwide predominantly in Europe. DIPs are a prefabricated driven pile system utilizing high strength ductile iron pipes which are manufactured using a spun-cast process having outside diameters of 4 5/8” and 6 5/8 inches. The standard pile lengths are 16.4 feet long. The pipes are manufactured with a tapered socket with an internal shoulder for full engagement at the top and a tapered spigot at the bottom. The individual pile sections can be connected with this Plug and Drive® connection to drive a pile of any length.(see figure 1)The DIP system’s inherent advantage is the simplicity of the installation process. The piles are driven to refusal or to a required penetration depth with the use of a high-impact highfrequency hydraulic hammer (ie. Breaker hammer). In most applications the hydraulic hammer is mounted on an appropriately sized excavator (see Photo 2). At the completion of driving the pile, the pile is cut off (see photo 5) and the remaining section of pile is fitted with the appropriate driving shoe and serves as the lead section for the next pile. Being able to reuse the cut off section, yields minimal if any pile shaft waste. The pile is then fitted with an appropriate pile cap plate to receive the load from the superstructure."

Jan 1, 2017

By Paul C. Schmall, Kevin Clarke, Paul J. Lewis, John M. Stanbury

"The $200M rehabilitation of the more than 100-year-old Gowanus Flushing Tunnel and pumping station located on the Gowanus Canal in Brooklyn, NY required deep excavations in an extremely congested urban environment. The environment posed significant challenges, including: support of excavation for protection of existing structures, excavation through man-made fill while eliminating groundwater inflow due to potentially contaminated groundwater chemistry; discharge and disposal impacts; and potential settlement of surrounding structures. This paper will present the design and construction challenges associated with the construction of a new combined sewer overflow (CSO) chamberwhich included a jet grout bottom seal, to mitigate groundwater inflow during excavation. The foundation for the finished structure also included a unique system incorporating the jet grout bottom seal elements with deep jet grout columns (piles) acting as the foundation system for the final structure. Design and construction challenges included highly variable soil conditions such as man-made fill, obstructions from previous construction, presence of an organic stratum, and conflicts with existing timber foundation piles. The jet grout bottom seal was constructed in loose sands with the deeper jet grout foundation elements extending to bear on a dense sand stratum. Challenges associated with the bottom seal included grid spacing and construction sequencing. Wet in wet sequencing was used to mitigate potential windows in the bottom seal further complicated by shadowing from existing timber foundation piles.Introduction And BackgroundModernization of the Gowanus Tunnel Pumping System required deep excavations in the extremely congested urban environment of Brooklyn, NY. The project location is shown on Fig. 1 and 2. The focus of this paper is to present the design and construction challenges associated with the support of excavation, control of groundwater, and ultimate foundation support for the combined sewer overflow (CSO) bypass chamber extension. The project site was tightly constrained by adjacent, active roadways and underground utilities, as well as residential and industrial structures. Therefore, excavation support was required to limit ground movement and maintain the integrity of the surrounding facilities. Excavation depths to as much as 16 ft below ground level, 8 ft below groundwater, required that seepage and groundwater be controlled so as to minimize pumping and disposal of groundwater and maintain the surrounding groundwater levels to avoid potential settlement of adjacent roadways, utilities, and structures. In addition, the subsurface conditions required that the proposed CSO bypass chamber extension be supported on a deep foundation to avoid differential and total settlements that may be detrimental to the existing and expanded structure. A plan view of the existing CSO bypass chamber and the proposed extension is shown on Fig. 3."

Jan 1, 2016

By Patrick J. Hannigan, Seth Robertson, Frank Rausche, Rozbeh B. Moghaddam

The Top-Loaded Bi-Directional Test (“TLBT”) and the conventional Bi-Directional Load Test (“BDLT”) are full-scale load tests where loads are applied bi-directionally to the foundation element. The BDLT uses an embedded loading source consisting of a jack assembly with one or multiple hydraulic jacks located between two steel bearing plates. As the jack(s) within the jack assembly is/are pressurized, the plates receive the load from the jack(s) and transfer these loads to the foundation element. In the case of the TLBT, the loads are also applied bi-directionally to the foundation element. However, in the TLBT case, the loading source is located above the foundation head. With the TLBT’s non-embedded and reusable load assembly, the loads are applied to the foundation using the steel shaft bearing and base bearing plates cast within the foundation. These plates are connected to the load assembly at the foundation head via Grade 75 or Grade 150, threaded, steel bars. This paper presents comparison results from a full-scale load test performed by both bi-directional load testing methods on adjacent test shafts. Details regarding subsurface conditions as well as test shaft construction and installation are included for the comparison tests. Test results and corresponding analyses are presented and discussed in detail.

Sep 8, 2021

By F Debidin

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

Jan 1, 2010

By Jeffrey Goodwin P. E., Melih Demirkan Ph. D. P. E., Kevin Tehansky P. E.

Just an hour drive down MD 301 from National Harbor, construction to replace the Governor Harry W. Nice Memorial/Senator Thomas ‘Mac’ Middleton Bridge (HNB) began in spring of 2020. The Maryland Transportation Authority (MDTA) contracted with Skanska-Corman-McLean (SCM) to deliver a new US 301 bridge spanning 1.9 miles from Maryland to Virginia over the Potomac River aiming to improve capacity, safety, and access of the roadway. The project area presented a geotechnical design challenge due to the installation of new bridge foundations in the problematic soils of the Atlantic Coastal Plain alluvial deposits. With the existing bridge remaining in service during construction, and the site’s logistical constraints placing new pile driving operations near existing abutments and piers, a complex instrumentation and monitoring plan was developed to ensure public safety throughout the project. This paper discusses the geological conditions of the project area, the collaborative approach of various design team members to develop an appropriate monitoring plan utilizing various instrumentation, an understanding of baseline conditional movements of the existing bridge, and impact response of adjacent construction activity to help deliver effective new bridge foundations while protecting the old ones.

Oct 1, 2022

By Mohammed Faizal, Abdelmalek Bouazza

"The operation of ground source heat pumps combined with foundation piles can have an effect on the thermal behaviour of the pile and the surrounding soil. This paper presents the effects of continuous heating, continuous cooling, and alternate heating and cooling operations on ground and pile temperatures as well as the thermo-mechanical behaviour of a field scale energy pile. The effect of pile operation on the ground temperatures is highest near the pile and reduces with increasing radial distance. The results of the present studies generally showed that the thermal elasticity of the pile is not affected.INTRODUCTIONGeothermal energy piles are foundation piles used as underground heat exchangers to maintain thermal comfort in buildings, via the use of ground source heat pumps (GSHPs). Ground source heat pumps are more economical and environmental friendly compared to conventional heat pumps. Energy piles can be combined with supplemental surface heaters or coolers, known as hybrid systems, for forcefully recharging the ground during non-operational times of the GSHP. Alternative heating and cooling of the GSHP improves geothermal energy usage and alleviates heat build-up in the ground and provides a balance of ground temperatures around the heat exchanger (Jalaluddin and Miyara, 2012).The temperatures induced in the piles during GSHP operation can lead to a complex response of thermal strains and stresses in the pile concrete. An assessment of the thermo-mechanical response of energy piles for various thermal loads may assist engineers in the design process. Furthermore, an assessment of ground temperatures will also highlight any potential thermal interactions with other energy piles in actual building operations.At present, the thermal strain and stress distribution in field scale energy piles has mostly been studied for continuous operation (Laloui et al., 2006; Bourne-Webb et al., 2009; McCartney and Murphy, 2012; Akrouch et al., 2014; Mimouni, 2014; Murphy and McCartney, 2014; Murphy et al., 2014; Wang et al., 2015). These studies have contributed considerably to the understanding of the axial thermal strain and stress distributions in the piles and have shown that pile thermal behaviour is mostly thermo-elastic without inducing major structural concerns.The present paper adds to the current knowledge by assessing the pile thermo-mechanical and ground thermal response for continuous and alternating thermal loads of a field scale energy pile. The operation modes studied are 24 hours continuous cooling (Faizal et al., 2015), 24 hours continuous heating, (Wang et al., 2015) and alternate heating and cooling operation (Faizal and Bouazza, 2016). The forced ground thermal recharging is done during the non-operating times of the cooling unit, simulating a solar hybrid GSHP system for a scheduled intermittent mode of operation."

Jan 1, 1900

By Amalia Giannakou

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

By Orestis Zarzouras, Amalia Giannakou, Jacob Chacko

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

Jan 1, 2017

By Howard A. Perko, Melinda J. Hummel

"Hydraulically jacked piles, herein referred to as jacked piles, are commonly used for underpinning existing structures to arrest settlement or augment an existing foundation for higher loads. They consist of steel pipe segments coupled together and jacked into the ground using a hydraulic ram. Pipe sections can vary in size from 3"" diameter to 18"" diameter or larger. Jacking resistance is typically provided by dead loads of existing structures. This type of piling system has been utilized for foundation underpinning, repair, and augmentation for more than 120 years, yet little has been published on the capacity, installation standards, and reliability of these systems. Pile load tests from a number of projects are presented and analysed. The data show that previous methods of jacked pile capacity and depth prediction are crude at best. Empirical relationships between capacity, depth, soil type, and standard penetration resistance blow count contain a high degree of scatter. Scatter in the data indicate capacity prediction for jacked piles needs further research and refinement.INTRODUCTIONPush pier, resistance pile, steel pier, and jacked pile are some of the names often applied to hydraulically jacked piles used for underpinning. The term ‘jacked pile’ is more common in building codes and will be used herein. Although jacked piles can be installed for new construction, this paper is focused on piles used for support of existing structures.Jacked piles consist of short segments of pipe or structural steel tube that are coupled together and forced into the ground using a hydraulic ram fastened to or beneath a footing, stem wall, or grade beam of an existing structure. In this way, the weight of the structure provides the resistance necessary to force the pile into the ground. A factor of safety can be achieved in design by redundancy, which is consecutively installing more than one jacked pile to support the same portion of foundation. Installing jacked piles consecutively using the same dead load and then releasing the load after each pile installation allows one to continue adding piles to the same general area until a total aggregate capacity is achieved to account for anticipated dead plus live loads and a desired factor of safety for that area.An engineering schematic of an example jacked pile connected to a footing foundation is shown in Figure 1. Modern jacked piles typically incorporate a steel bracket. There are many sizes and styles of brackets available. Some categories include plate brackets that bolt to the outside of an existing foundation wall, wide and narrow angle brackets that extend under existing footings, pin brackets for attachment to structural steel, and reverse angle brackets for attachment to footing and wall. Table 1 lists example brackets and their benefits."

Jan 1, 2017

By Ronaldo Luna, Donald Deardorff

"The use of load and resistance factor design (LRFD) is well documented since the 1960s for structural applications when it was first adopted into the American Concrete Institute Building Code in 1963 and was established for geotechnical applications by the Danish Geotechnical Institute about the same time under the name of Limit State Design (LSD).The Federal Highway Administration required all federally funded projects to use the LRFD method by 2007. Due to this funding requirement, recent LRFD research for geotechnical applications has focused on common bridge foundations (i.e., driven or drilled shafts), resulting in good documentation for design using these methods. Unfortunately, the practicing geotechnical engineer does not intuitively know how to create resistance factors for deep foundations systems that have design methodologies and installation techniques significantly different from driven or drilled shaft foundation systems.Helical anchors typically use semiempirical methods for preliminary capacity design and a torque correlation methodology during installation to verify required capacity. Here we provide basic information on the LRFD methodology for helical anchor design. Additionally, the First- Order Second Moment (FOSM) method is applied to a previous helical anchor study (Hoyt and Clemence 1989) to determine resistance factors for an ultimate tension capacity strength limit state.MethodologyThe concept of the LRFD method is to establish factors for both the load and resistance that account for uncertainties using probability theory. The factors increase the nominal load and/or decrease the nominal resistance such that the probability of failure is an acceptable value. LRFD also accounts for the effects of load combinations (dead, live, seismic, wind, etc.) by determining the probability of the combined occurrence. The general form of the LRFD equation used by American Association of State Highway and Transportation Officials (AASHTO) is:"

Jan 1, 2009

By Alexander Ciccone, John H. Gill

Jet grouting is a highly versatile ground modification technique that can offer significant commercial and technical advantages over traditional concrete pit underpinning applications. Despite these advantages, jet grouting remains an underutilized technique in the construction industry due to its perceived complexity, cost, and risk. When performed thoughtfully, underpinning by jet grouting offers significant safety and schedule advantages over traditional underpinning approaches. The New England construction market has seen a recent acceptance in the use of jet grout underpinning on congested project sites across a variety of subsurface conditions. The reduction of the cement batch plant footprint due to equipment advances has allowed the use of this technique in urban sites where its use would be previously infeasible. Furthermore, jet grout underpinning has been utilized for support of historic and sensitive structures with generally lower tolerance to settlement than is typically feasible with conventional pit underpinning. Robust, real-time geotechnical instrumentation monitoring systems have helped reduce the uncertainty and further expand the feasibility of jet grout underpinning applications. When properly designed and constructed by qualified and experienced jet grouting contractors, the flexibility of soilcrete for design and construction may be utilized to overcome the many inherent challenges which complicate underpinning and earth retention systems. INTRODUCTION The construction of buildings and infrastructure in our increasingly dense urban spaces often requires excavations below the elevation of existing structures immediately adjacent to the proposed work. Where a proposed excavation system encroaches into an existing structure’s zone of influence, additional measures, such as the construction of an underpinning or excavation support system, are required to safely excavate and minimize the impacts on the adjacent structures. Jet grouting is one method of underpinning that offers significant commercial and technical advantages over many other techniques. Though it was first used to the United States in the 1980s and has grown in popularity elsewhere, jet grout underpinning remains underutilized domestically due to its perceived cost and risk premium. Jet grouting has significant technical advantages over other underpinning methods due to its applicability in a wide range of soil types and its flexibility of design and installation. The jet grouting process is capable of limiting the movement of foundations during construction and excavation to lower thresholds than most traditional underpinning methods (Droof, Furth, & Scarborough, 1995). Its use for underpinning historic and sensitive structures with lower settlement criteria provides additional evidence to its technical utility. Through thoughtful design, adequate planning, and experienced installation, jet grouting can be an appropriate underpinning solution that can provide significant cost and schedule savings.

Jan 1, 2019