Search Documents

By Charles G. Crans, Naresh Gurpersaud

"Toronto’s Union Station, a National Historic Site occupying an entire city block, is the busiest commuter rail transportation hub in Canada. An extensive project is being undertaken to revitalize Union Station while maintaining the historical significance of the building and minimizing disruption to commuters. A significant stage of the revitalization involves excavation indoors, to a depth of up to 5.5 m below the existing floor level to create space for a new transit concourse and a new lower-level pedestrian retail concourse. A hybrid excavation support system utilizing micropiles as soldier piles was constructed over an 18 month period between 2010 and 2011.Development and testing of connections between the micropiles, shotcrete facing, lagging, walers, and tiebacks presented significant challenges. The existing viaduct structure was constructed in the 1920’s on land reclaimed from Toronto Harbour, so there was significant (and ongoing) uncertainty with respect to buried obstructions including relic timber wharfs and abandoned steel and timber piles. Collectively all these conditions precluded the use of conventional methodology; new techniques, installed using modified equipment, and for the first time in the Greater Toronto Area, were required.Details of the existing site conditions, installation challenges, design, construction and performance of the hybrid excavation support system inside this historic structure are presented.INTRODUCTIONUnion Station in Toronto, Ontario is the busiest passenger rail facility in Canada, with 65 million passengers annually and an average of 200,000 passengers each day. Construction of the station was completed in 1920. It has been designated a National Historic Site of Canada and inducted into the North America Railway Hall of Fame in the Facility and Structure category.The Union Station Revitalization Project (USRP) was tendered in 2010 and awarded as a 6-year, $450M construction management / trade contract package. Included was a large scale grade reduction, referred to as “The Dig Down”, to create two basement levels and this required extensive excavation support constructed entirely indoors within the active station setting."

Jan 1, 2017

By Garland Likins

The Texas Department of Transportation, now considering using Augered Cast-In-Place (ACIP) Piles (also known as Continuous-Flight-Auger or CFA Piles) in their foundations, awarded a research project to Professor Mike O'Neill at the University of Houston (UH) to study the advantages and potential difficulties with ACIP/CFA piles. ACIP/CFA piles were installed on three sites for UH; they had extra instrumentation and additional measurements by UH staff during installation which are beyond the scope of this paper. Independent visual logging of the pile was done by an experienced inspection firm. The main advantages of ACIP/CFA piles are their speed of installation and their economy. Potential savings are substantial. Disadvantages include an unknown structural condition of the shaft. Inspection is critical, but many simultaneous observations make accurate inspection difficult. Because of resulting uncertainty, many engineers have avoided ACIP/CFA piles in the past.

Jan 1, 1998

By Piotr Kozlowski, Stanley L. Worst, Matthew J. Niermann

Circular secant pile shafts were installed along the tunnel alignments for both the Ohio Canal Interceptor Tunnel project in Akron, Ohio and the Ohio River Tunnel project in Louisville, Kentucky. The diameters ranged from 34 to 51 feet and the depths ranged from 49 to 107 feet. Verticality and concrete volumes were measured on all piles to verify compliance with the design, which for some shafts consisted of a finite element model with multiple openings using unreinforced concrete secant piles. All secant piles were drilled into rock to seal off the groundwater. This paper will discuss the design, construction and quality control of the secant piles for these projects. INTRODUCTION Many Midwest and Northeast cities have Combined Sewer Overflow (CSO) systems which discharge pollutants into waterways during wet weather events. One way to remedy this issue is to provide a temporary overflow tunnel. A temporary overflow tunnel connects to the combined sewer system and collects the overflow during wet weather events, storing the wastewater until the event has subsided. After the storm event, the stored wastewater can be pumped to the treatment facilities and processed as normal. Project Background – Akron, OH The Ohio Canal Interceptor Tunnel (OCIT) project was performed as a result of the Environmental Protection Agency’s (EPA) Consent Decree with the City of Akron, Ohio. This Consent Decree required modification of the existing Combined Sewer Overflow system. The resulting project consisted of a 27- foot diameter tunnel with multiple points of entry to capture the sewer overflow and prevent it from entering waterways. The tunnel is over 6,000 feet long and is as deep as 150 feet below the ground surface; see Figure 1 below.

Jan 1, 2019

By Andrew Budek

Reinforced concrete piles are used to carry foundation loads through considerable depths of soil to provide superstructure stability under gravity loads and lateral forces. The creation of cast-in-place (or cast-in-drilled-hole, i.e., CIDH) piles begins with the auger-drilling of a hole of the appropriate depth, into which a cage of reinforcing steel is placed (the cage length is generally equal to the depth of the hole, a construction joint being used to connect the in-ground pile with the superstructure). The pile is then finished by casting with concrete, and the superstructure then appended. The superstructure may either be a column (denoting the structure a pile-column), a column and cap beam, or a footing. Typical pile-column configurations are shown in Fig. 1 (a CIDH pile used in a footing would be similar in overall configuration to Fig. 1(b), with H=0). CIDH piles are well-suited for alluvial soil profiles with a deep water table; such conditions generally allow the auguring of a clean and regular hole.

Jan 1, 2007

By D. J. Ketkar

It is a frequent experience to find that the Sub-surface Investigation (S.I.) data is either inadequate or misleading. However, such cases are rarely reported. Nonetheless, the projects suffer on-account of delays, cost-over-runs, disputes and/or compromise of the safety norms. Many times S.I. is considered unnecessary or is carried out as a ritual, mainly due to (i) non-availability of good S.I. agencies, or (ii) absence of Geotechnical consultant, or (iii) shortage of time. Importance of S.I. cannot be over emphasised. Yet the profession is in a state of confusion - mainly because of lack of competent professional agencies and of well-defined roles/responsibilities of the concerned parties. In this paper, some suggestions are made to get better returns from the S.I. activity.

Jan 1, 1996

By R. Lee Wooten, David R. Shields, Darren D. Clark

"Borehole permeability tests that measure flow or head changes in boreholes located within seepage barrier walls are commonly used to estimate the in situ permeabilities of those walls for quality control and assurance. The current state of practice for estimating permeabilities from these barrier wall borehole tests is to use equations published by M. J. Hvorslev in 1951. Hvorslev’s borehole test equations model an infinite stratum of uniform permeability, which is not the actual condition for a test performed in a low permeability barrier wall located within a high permeability stratum. We examine and develop alternative equations based on line source analytical models, which more closely match barrier wall test conditions. We describe how these alternate equations can be used to estimate barrier wall permeabilities from borehole tests and compare the results to those obtained from the Hvorslev models. We also provide recommendations that consider differing upstream and downstream water levels.Barrier Wall Permeability Tests - State Of PracticeThe installation of seepage barrier walls has become more common in a variety of applications ranging from dams and levees to contaminated sites requiring retardation of groundwater flow. The types of seepage barrier walls and installation methods include soil-bentonite, soil-cement-bentonite, concrete, self-hardening slurry, geomembranes, and sheet piles, installed with various soil mixing, slurry-supported trench, and driving methods.Owners and contractors have used a variety of methods to evaluate the permeability of these seepage barriers. The following table lists commonly used quality control/assurance tests for evaluating the permeability of a seepage barrier."

Jan 1, 2016

By George J. Tamaro

The design and construction of foundations in the New York City area are usually dictated by the widely varying geologic conditions encountered in the five boroughs, particularly along the spine of Manhattan Island. Rock extends well above sea level at the northern reaches and falls to depths in excess of 250 m at the barrier islands at the southern extremities. These highly variable geologic conditions, significantly affected by glacial activity, dictate different design and construction approaches throughout the five boroughs of New York City. Extensive rock removal is required at the north while long piling is dictated in the south. Similar changes can occur within a project site on Manhattan Island. This paper will describe these conditions in general, will identify the various solutions used to solve these problems and will summarize various foundation types used in the New York City area.

Jan 1, 2000

By Randy R. Williams, Brian W. Wilson, George M. Filz, Marina S. W. Li, Donald A. Bruce

"In-situ wet grab sampling and post-installation coring of soil-cement structures are typically carried out for Quality Control (QC) and Quality Assurance (QA) of deep mixing (DM) schemes. Wet grab sampling and testing is used to provide data to indicate that performance requirements are being met during production, in advance of coring, which typically occurs at 28 days or later, following installation. While unconfined compressive strength (UCS) tests from wet grab samples provide good production indicators, industry practice often requires that acceptance criteria of soil-cement structures be based on UCS results from representative core samples.This paper outlines the approach adopted for field sampling and QA/QC testing carried out in highly variable subsurface conditions at a site located in northern British Columbia (BC), focusing on postinstallation soil-cement coring and strength testing for an extensive deep mixing scheme. A discussion on suitable methods of coring soil-cement structures and appropriate selection of samples for testing that are representative of the in-situ soil-cement structures is provided. This paper also discusses the selection strategy adopted for verification of strength and modulus parameters used for design, providing spatial and time coverage, as well as the acceptance criteria implemented, and provides comparisons with published industry recommendations.BACKGROUNDAn extensive deep mixing ground improvement scheme was completed for the development of a Liquefied Natural Gas (LNG) Facility to be located in Bish Cove, BC, Canada. The deep mixing scheme was implemented to treat very weak native deposits in-situ to support two mechanically stabilized earth (MSE) walls up to 20 m (66 ft) high, and their associated bulk earthworks. Within the DM area, the subsurface conditions were highly variable, ranging from deep (up to 21 m (69 ft) thick) deposits of very soft to soft clayey silt to silty clay, overlying layers of dense to very dense gravelly sand to sand and gravel, to compact deposits of silty sand (up to 15 m (49 ft) thick), overlying dense sand and gravel. Bedrock was encountered beneath the granular deposits and generally comprised granodiorite with occasional andesite dykes."

Jan 1, 2015

By Sastry Putcha, Santosh Mummaneni, Avasarala Swamy

"Inspection of bored pile hole bottom prior to placement of concrete is one of the most crucial element of foundation design and construction, especially for end bearing piles. Pile hole bottoms that are not cleaned well for sediments could potentially result in settlement. Although many projects have specifications in-place for drilled pile hole inspection, they are rarely implemented as the current available tools are either unsafe or cumbersome and costly, thus making it very unattractive for owners and contractors. Further, sometimes the post-construction nondestructive quality control testing such as PIT or sonic logging on piles resulted in unanswered questions related to soft bottom. This generates costly disputes with additional testing including concrete coring and possible repairs. Currently, there are several bored pile bottom inspection devices in USA, namely, SID, DID, and SQUID which can either provide video and photo documentation or measure sediments.“ShaftCam”, a patented advanced Digital Borescope, was invented to address the issues related to pile hole bottom inspection with its ability to measure sediments as well as photo and video documentation. Shaftcam device consists of 8-inch diameter bell with a camera, led lights, air hose connection and penetrometer with digital measurement that are connected to a control power box and laptop through a cable. The bell is fitted with a round clear open fiberglass skirt to form an open chamber. A simple motorized winch frame allows the user to lower the ShaftCam equipment gently to the bottom of the shaft at the desired location. Once the bell with camera is lowered to the bottom of the hole, air is pumped into the clear chamber to displace the water/slurry/polymer and get a clear view of the hole bottom to record the conditions and measure the sediment thickness and resistance. The skirt can also be enclosed and lowered to the desired location to allow for inspection of shaft walls.ShaftCam weighs less than 15 lbs. (6.8 kgs) in water and allows for inspection of the hole by one person in less than 30 minutes. Use of ShaftCam has saved significant time and money and thus allowed owners and contractors to readily accept and implement the quality control measures in many projects in USA over past few years."

Jan 1, 1900

By Kanagarajah Ravishankar

Drilled shaft (caisson) foundations are extensively used in the past. In the central part of New Jersey, the soils consist of silt and clayey silt overlying Triassic age shale bedrock. The shale is friable and generally severely weathered and highly fractured. The shale crumbles readily into small fragments. In general, the shale is encountered in shallow depth. Subsurface investigations indicated that the upper part of the shale is very soft, highly weathered, and able to advance through soil exploration methods. The underlain formation is relatively hard and required rock coring techniques for sapling. Individual core recoveries ranged from 10 to 100 percent and Rock Quality Designations (RQD) vary from 0 to 90 percent. Although several methods available to estimate the axial capacity of drilled shafts, it is a difficult task for the designer choose the suitable method due to self disintegrate nature of the shale. In the recent years several bridge foundations have been constructed using drilled shafts founded on shale rock in the vicinity of the central New Jersey. Based on load tests carried out on drilled shafts during construction, subsurface exploration, and laboratory tests, suitable methods for determining axial capacity of drilled shafts is analyzed. This paper presents the findings of the field tests and suitable methods to determine the axial capacity of drilled shaft founded on soft shale. Key words: Drilled shaft, axial capacity, Osterberg load test, shale.

Jan 1, 2006

By Venugopal Bonani, Kumaran M., Thomas John

Liquid storage tanks are usually located in nearshore or coastal regions with soil profiles containing thick layers of compressible soils. These storage tanks are usually of large diameter up to 90m and carry high loads, and the tanks are supported by heavy deep foundations such as piles. These structures are subjected to huge lateral loads due to wind and earthquake, and any damage to storage tanks with highly inflammable liquids leads to disastrous condition. So, it is important that the top layer of soil (up to the fixity depth) should be strong enough to provide the required lateral load capacity to the pile. In a project for constructing LNG terminal in Odisha containing 2nos of 89m diameter LNG storage tanks supported with pile foundation located near to coastal region, for improving the lateral capacity of existing soil, the top 3m was replaced with compacted engineered fill (GSB). The site was a filled-up area with dredged soil from seabed, the top 5m-10m were soft to medium stiff clay with SPT N less than 10. The lateral design load on pile was 534kN under free head condition. Actual lateral capacity for the strata was around 200kN under free head condition which was less than required capacity as per structural requirements. Therefore, for improving the lateral capacity of pile the top 3m soil is replaced with well compacted engineered fill (GSB) in layers of 150mm and the capacity is proved by conducting initial and routine lateral load tests. This paper describes the properties of the engineered fill used and how the lateral load capacity of pile was improved to meet the design requirement.

Sep 1, 2022

By Liiban A. Affi

The most difficult task of designing multilevel tieback walls for deep excavation support is the determination of lateral stresses. These lateral stresses act not only on the shored height, but also on the embedded portion of the soldier pile, all the way down to the pile tip. Examples of lateral stresses include uniform surcharge load (soil spoils or equipment), strip load surcharge from Cooper E80 (train loads), line load surcharge (exterior footing or retaining walls), and point loads (cell tower). In this paper we will discuss the various surcharges, do step by step example calculations and show how to take the total lateral stress output and present the design pressures for direct use by the substructural designer. Included is a case study from a project Anaheim Hills, California, USA.

Jan 1, 2010

By Lenin T., Madhav M. R., Padmavathi V.

Use of PVDs and preloading on the ground can significantly reduce the time taken for ground to consolidate. Many soils in situ are lightly overconsolidated, with overconsolidation ratios (OCR) ranging from 1.0 to 2.0 due to various reasons such as glaciation, ground water level fluctuation, aging, cyclic loading, creep, erosion, cementation, etc. The effects of overconsolidation ratio are analysed in this study. Compression index and consolidation coefficient are important parameters in determining time – settlement response of soft soils under preloading and with PVDs. These parameters are typically estimated using oedometer tests on samples, with the assumption that the results represent the entire deposit. The in-situ time-settlement plots at different depths are used in the back analysis for estimating compressibility and consolidation parameters of in situ ground, resulting in more representative values that reflect the deposit's overall behavior. From observed time versus settlements plots, variations of compression index and coefficient of consolidation with depth of a deposit are presented. Estimation of compression index with depth is possible based on different OCR values as shown in this study. Barron (1948), Asaoka methods are used to estimate the coefficient of consolidation with flow in the radial direction.

Sep 1, 2022

By Michael Arnold, Jignyash Manyam, Yoav Rappaport

The USACE required construction of over 13 miles of cutoff wall at an average depth of 65 feet for the Herbert Hoover Dike (HHD). To meet project requirements, to provide quality control and make sound operational decisions, automated data capture, retention and visualization is crucial. Accurate and complete data management allows the authors to deliver critical business insights and to improve operational efficiencies. The author’s understood the necessity of capturing all their data, and efficiently processing and displaying it for multiple stake holders, for both internal and external purposes. The authors realized early in the project life cycle that data ownership and management is one of the fundamental features of the construction process. The authors developed their own software and use two in house applications; WEB-BGM online portal and, b-project which store rig production information combined with field quality control. b-project is used to create and deliver the Enterprise Database (EDB) to the USACE. Another biproduct of capturing the production data is the generation of the Geographic Information Systems (GIS) and also business analytics visual interactive display, developed through Microsoft Power BI. The paper focuses on the business process workflow and various technologies employed and lessons learned from the field operator perspective to achieve higher returns on business software operations.

Oct 1, 2022

By Mario Mauro

In 2007 the US Army Corps of Engineers classified the Herbert Hoover Dike in Florida as a Dam Safety Action Classification (DSAC) 1 dam, and started the implementation of one of the largest dam rehabilitation projects in the nation. The construction of the cutoff wall is a key feature of this rehabilitation work to upgrade the dike to current dam safety criteria. The cutoff wall installation is currently being completed on Reach 1, which extends from Port Mayaca to Belle Glade, under a Multiple Task Order Contract based on performance specifications and stringent verification criteria. For the construction of the cutoff wall TREVIICOS selected the self-hardening slurry method. Since the cutoff wall is installed through a layer of highly variable limestone with Unconfined Compressive Strength (UCS) up to 14,000 psi, the excavation requires the use of the hydromill equipment. This is the first successful application of the hydromill technology with self-hardening slurry in a large scale project in the US. This paper presents the details of the method utilized, the quality control procedures, and the experience gained over seven miles of cutoff wall installed.

By Keith MacKay, John Carter, David Siddle, Fernando Faminia

"The River Green Residential development, is located in the municipality of Richmond, BC adjacent to the Fraser River. Ground conditions at the site consisted of medium to fine grained alluvial sands and a high groundwater elevation. A temporary low permeability retaining wall was required in order to facilitate the construction of an underground parking structure without inducing settlement of adjacent structures, which include the Richmond Olympic Oval; part of the legacy of the Vancouver 2010 Winter Olympics. Golder Associates Ltd. and GeoPacific Consultants Ltd. utilized Cutter Soil Mixing (CSM) technology to enable construction of a continuous combined low permeability cut-off and retaining wall around the perimeter of the property. The 350m long wall was keyed into marine clay at a depth of 28m below ground surface, and contained H-Pile reinforcement installed at regular intervals. The CSM technology provided many benefits for this project, allowing the combined cut-off and retaining wall to be constructed within a very narrow footprint (650mm width). The low noise impact and near vibration free construction of the CSM equipment provided minimal inconvenience to nearby stakeholders during construction. To reduce dewatering volumes during excavation and prevent significant water-table drawdown the Hydraulic Conductivity requirements for the wall were 1 x 10-7 cm/s or less. Project specifications called for a different strength requirement for upper and lower portions of the wall. The top 13 meters of the wall required an Unconfined Compressive Strength (UCS) of 4MPa to act as a retaining and cut-off wall, whereas the bottom 15 meters of the wall required a UCS of only 0.5 MPa to act only as a cut-off wall. Wet-grab and core samples were obtained from the panels to confirm the UCS and Hydraulic Conductivity specifications were met.INTRODUCTIONGolder Construction Inc. and GeoPacific Consultants Ltd. conducted the design and construction of a deep soil mixed cut-off and retaining wall system. The “dry-box” solution was used to surround the excavation of an underground parkade and prevent flows of groundwater into the excavation."

Jan 1, 2016

By Dale E. Berner

A new navigation dam at Olmsted on the Ohio River will be built "in-the-wet" using a lift-in construction method by the Washington Group/Alberici Joint Venture for the U.S. Army Corps of Engineers, Louisville District. Up to 4,000-ton precast concrete dam shell segments will be prefabricated on the Illinois riverbank and lowered into the river on a marine skidway and cradle. A 4,500-ton capacity catamaran crane barge will lift the precast concrete shells and lifting frames from the cradle, and transport them partially submerged to a piled foundation pre-installed underwater. Tremie concrete will be used to compositely connect the shells, piles and sheet pile cut-off walls. This paper focuses on the pipe-pile foundations for this half-mile long navigation dam, and for the temporary precast yard and marine skidway. The dam foundations are designed to resist large ground motions from the New Madrid Fault Zone, and selected production piles are designed to serve as landing piles to support the shells during the construction process. Specific foundation issues addressed in the paper include: pile load tests; production field testing requirements; controlled fixity 24-inch diameter pipe-pile design including seismic considerations; cut-off wall design; sheet pile cellular fixed weir design; isolation jOint design; and temporary works foundation designs for both the precast yard and the marine skidway, including testing of 42-in diameter pipe piles.

May 11, 2007

By Dominic Parmantier, Jason Page

"In the past, the designers of DSM have analyzed various failure modes and then specified a minimum unconfined compressive strength (UCS) for the soil-cement. The specified minimum UCS reflected the compressive stress in the soil-cement under design loads and an appropriate factor of safety. With the increased use of finite element analysis for the design of DSM applications where allowable strain as well as stress are considered, there is a growing trend for designers to specify a modulus and occasionally a tensile strength for the soil-cement in addition to the UCS. This paper compares the relationship of modulus and tensile strength to UCS for soil-cement from a recent DSM project with unique testing requirements. These results are compared to published data. The case is made that designers should utilize published relationships to characterize the required strength and stiffness by a single acceptance criterion: UCS.INTRODUCTIONAs the use of DSM has increased in popularity so has the use of service state deformation analysis in lieu of more traditional failure mode analysis. Most DSM designers are interested in the appropriate modulus values and occasionally tensile strength values of soil-cement as well as simply the unconfined compressive strength (UCS) of soil-cement.Although there are numerous published correlations between the UCS, tensile strength and modulus of soil-cement, some DSM project specifications are produced which have acceptance values for tensile strength, modulus, and UCS. If this specification of multiple strength properties is consistent with the nature of soil-cement, then there is really no harm except for the expenditure of client money on unnecessary testing. If however the multiple strength properties specified are inconsistent with the material properties of soil-cement, then the specifications can create the expectation that the DSM contractor can somehow create a custom soil-cement with tensile strengths and modulus characteristics which are unachievable.This paper presents a brief summary of a project in Burnaby, B.C. which specified minimum values for the tensile strength, modulus, and UCS of the soil-cement. A comparison of those test results to published correlations between the UCS and the tensile strength is presented. Additionally, a comparison of modulus derived from two different methods of testing is presented along with a comparison to published correlations between UCS and modulus for soil-cement."

Jan 1, 2015

By Gene Bryant, Wesley Schmutzler, Matteo Bertoni

The levees where the Mississippi River and the Lower Wood River meet near East Alton Illinois have been a problem area for years due to underseepage. The first phase of the deep cutoff wall was a 2,000-linear foot section that was completed in 2016 for the Illinois Flood Prevention District Council. This section was installed along the Wood River and the Mississippi river to depths of over 135’, The United States Army Corps of Engineers was tasked with continuing the cutoff wall along the Mississippi river. The wall was a continuation of phase I with depths up to 140’. The 1,000’ long cutoff wall was installed through fill, loose sands, cobbles, and sandy clay. The cutoff wall was terminated in either Glacial Till or sound rock. In order to provide wall permeability equal to or less than 1.0 X 10-6 cm/sec a self-hardening slurry (SHS) composed of ordinary Portland cement, slag cement, and water was utilized. The depths reached on this project using SHS is the deepest done to date in the United States. Along with the permeability requirements, a very narrow range for the unconfined compressive strength was specified at 50 – 180 PSI. In order to monitor the ground movement and water level fluctuations during the excavation of the panels with the Hydromill or Clamshell, 6 automated inclinometers were installed and monitored continuously during panel excavation in phase 1. Seven automated piezometers were monitored in phase 2. This paper will give an overview of the project with emphasis on the effect of the excavation on the instrumentation, specifically the reaction of the piezometers as the last panels were installed. INTRODUCTION The project is in Illinois, about 1000 feet downstream from where the Wood River Creek enters the Mississippi River between East Alton, IL and Wood River, IL adjacent to State Highway 143 (Fig. 1). The Wood River Lower Cutoff Wall Phase 2 Project (WR2) was awarded to TREVIICOS SOUTH (TIS) in September 2017. The Main Project features are: Construction of work platform, inclinometers installation and removal, cutoff wall construction by the Self-Hardening Slurry method (approx. 135,000 sf) up to 140' depth, clay cap installation, and site restoration. The levee system along this stretch of the Mississippi River has been plagued by under-seepage for several years. The phenomenon has worsened to varying degrees, depending on location, to the point that remediation was needed to ensure that Levee failure would not be an issue in the future.

Jan 1, 2019

By Patrick E. Durnal, Henrik Dahl

"A joint venture of Ben C. Gerwick Inc., Sverdrup (now Jacobs) and DMJM (now DMJM + Harris) designed the $779 million seismic upgrade of the Richmond - San Rafael Bridge over the San Pablo Bay in the San Francisco Bay Area and provided construction support to Caltrans. Construction of the marine foundation retrofi t was completed by a joint venture of Tudor Saliba/Tidewater/Koch-Skanska and their subcontractors: Pomeroy Precast Construction, AGRA Foundations, Dutra Construction and Vortex Divers. Construction management and inspection was performed by Caltrans with the support of various consultants. MARINE FOUNDATION RETROFIT SCOPEThe retrofi t design of the submerged foundations included:??A total of 476 tension and compression micro piles (290- 1140 kips or 1290-5071 kN) installed through cored holes through the underwater bells at 31 pier locations??Fourteen 126/150/164 inch (3.20/3.81/4.17m) diameter CISS (Cast-in-steel shell) concrete shear piles (1160- 2660 kips or 5160-11832 kN) installed through new precast concrete pile cap extensions??Twelve CIDH (Cast-in-drilled-hole) shear piles (1060- 2130 kips or 4715-9475 kN) with 150 inch (3.91m) diameter steel shells to top of bedrock and 30 ft (9,14m) long and 11 ft (3.35m) diameter rock socket installed through new precast concrete pile cap extensions The specifi ed post bid test boring revealed deeper bedrock at one pier location allowing deletion of the rock socket. Thus 15 CISS and 11 CIDH shear piles were installed at 11 pier locations - 9 piers with 2 piles and 2 piers with 4 piles. Cut off elevations for the shear piles ranged from 46 ft to 60 ft (14.0m to 18.3m) below mean sea level and cut off for the micro piles was 8 ft to 46 ft (2.44m to 14.0m) below mean sea level. Almost all foundation retrofi ts required work under limited headroom conditions. Underwater construction connections required innovative design details and construction techniques for each pile type. The 11 piers had 22 precast concrete pile cap extensions installed in pairs and connected by either tremie concrete closure pours or by large pipe struts. The precast pile cap extensions were strapped underwater using large steel bands wrapping around the belled piers with grouted annulus. The precast pile caps were founded with 14 inch (355mm) diameter steel pipe piles, which were either support piles or seismic tension and compression piles. The seismic piles were connected in grouted corrugated steel pipe sleeves cast into the new concrete pile caps."

Jan 1, 2007