Search Documents

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 Quanchen Sun, Mohammed Z. E. B. Elsahife, Anthony Fisher, Chris Barker, Jennifer Schooling

A review of the literature shows that pile integrity is a significant concern in pile construction. Recently, a new integrity test, thermal integrity profiling (TIP,) has been put into use in foundation construction. It measures temperature changes and thermal profiles of concrete during curing. Heat generation and dissipation of early-age concrete is determined by the concrete mix, the ground conditions and the shape of concrete structure. The current data interpretation practice is primary based on experience. Anomaly detection through direct analysis of temperature profiles is currently indicative or suggestive and temperature signatures are usually similar, and numerous causes are not easily isolated. The core of the TIP testing technique, i.e. collecting detailed temperature measurements along the pile during the hydration process, is promising but a new interpretation approach is required. In this paper, a new interpretation approach has been developed in which TIP constitutes the first step. An investigative staged process is then followed to establish and assess the anomalies in the problematic regions along the pile employing the combined use of detailed finite element (FE) simulations, the actual temperature data from TIP and genetic evolution algorithms. In each stage, more details could be revealed about the anomalies being investigated including, ultimately, location, size and shape; this staged process enables practitioners to follow a riskbased approach and decide whether or not to pursue subsequent stages depending on the results they get at the end of each stage. This new approach, depending on the stages required for the analysis, will potentially avail practicing engineers of crucial test results about the quality of the pile immediately following pile construction, hence enabling repair and remedial work straight away at a lower cost.

May 1, 2022

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

The Top-Loaded Bi-Directional Test (―TLBT‖) and the conventional Bi-Directional Load Test (―BDLT‖) are full-scale static load test methods. In both methods, the test loads are applied bi-directionally to the deep foundation. The advantages of the conventional BDLT have been well established for cost efficient static load testing of deep foundations, particularly for large diameter, high-capacity drilled foundations. A conventional BDLT applies the bi-directional test loads using an embedded jack and bearing plates. The TLBT method also applies the bi-directional test load to embedded bearing plates but does so using reusable high-strength threaded bars attached to an above-grade hydraulic jack and load transfer assembly. The new TLBT method is well suited for load testing shafts of a moderate diameter, length, and nominal resistance or ultimate load. TLBT advantages include economic considerations resulting from the method’s reusable load application components and constructability considerations as it readily accommodates a center concrete tremie pipe or pump line location. This paper presents comparison results from full-scale load tests performed using both bi-directional load testing methods. Adjacent 3-foot diameter by 30-foot long BDLT and TLBT shafts were tested. Details regarding subsurface conditions and test shaft construction are included for the comparison of the TLBT and BDLT results. Corresponding test data and analyses for both test shafts are presented and discussed in detail. The BDLT shaft had a maximum uni-directional load of 240 kips at upper and lower bearing plate displacements of 0.5 and -3.8 inches, respectively. The TLBT had a maximum uni-directional load of 300 kips at upper and lower bearing plate displacements of 1.0 and -5.9 inches, respectively. These results as well as the load-transfer behavior and equivalent top loading curve results from the adjacent BDLT and TLBT drilled shafts are discussed. The paper also discusses the strain gage instrumentation on the TLBT load application bars and on the embedded bearing plates.

Oct 1, 2022

By Fei-chiu Huang

A 17-acre landslide occurred in February 2001, on a slope below Via Bellota in the City of San Clemente, California. Three homes were destroyed and many others placed in jeopardy. The landslide, involving portions of five separate developments, continued to move significantly in the years following. Litigation ensued among the affected parties, and investigations continued through 2007. A mediated repair resolution was ultimately reached among the parties. The agreed upon repair consists of a multi-million dollar stabilization program that included grading, drainage, and structural systems. Part of the construction cost was offset by creating 4 new ocean view custom lots and 20 new mobile home lots. The landslide repair and slope stabilization design involved removal and replacement of portions of the landslide debris and construction of buttress and stabilization fills as well as installation of 74 shear pins in two rows. The shear pins were designed as 4-foot diameter by 50 feet in length and incorporated continuous W30x211 wide flange steel. The shear pins were designed to be installed 25 feet above the slide plane and 25 feet below the slide plane at each location. Construction of the 74 shear pins was initiated in 2008 and completed in 2009. Four-foot diameter holes were drilled by utilizing a truck-mounted, flight-auger-style drilling rig with a 4-foot diameter solid-flight auger. Prior to the installation of the shear pins, an engineering geologist downhole logged strategically selected holes to further evaluate the actual slide plane elevations. The wide flange steel shear pins were then lowered to the desired elevations and encased within 4,500 psi, Type V, 0.45 maximum water/cement ratio concrete. Inclinometers installed within four pin shafts and behind the pin rows indicated performance in accordance with the design. Slight to non-perceivable shear displacement was measured which mobilized the intended capacity at the monitored shear pins. No excessive slope movement was detected at any of the inclinometer locations during or after the construction period. Actual shear displacement of the steel wide flange elements was less than the movement anticipated before shear pin installation.

Jan 1, 2010

By Francisco A. Flores, Rigoberto Torres

The Complementary Technical Standards of Mexico’s City Building Code do not mention the criteria to compute the bearing capacity of Steel H-piles. It is necessary to increase knowledge in using steel H-piles as foundation elements in very soft soils of Mexico City. Considering their applicability to reinforce structures as well as new foundations in confined spaces, this research is proposed to obtain the axial load capacity of piles at scale in laboratory. This paper describes the construction and testing of scale models in laboratory of steel H-piles to measure their axial compression and tension load capacity in the soft soils of Mexico City. Three types of piles were fabricated at scale. Tests were performed on individual piles and pile groups. Based on the axial load tests, the load-displacement curves are presented both in compression and tension. The analysis of the results is shown, and comments are given regarding the ultimate bearing capacity of piles. Recommendations are presented regarding the determination of the bearing capacity of these piles in the very soft soils of Mexico City.

Sep 8, 2021

By Ronald D. Boyer

"Early in the design stage of Meadowlands Xanadu, the client’s project director informed me that “after construction, nobody is going to come to Xanadu to see the foundations.” My response was, “Well, that’s good, because the only reason someone would come to see the foundations is if there is a problem with them.” The client’s real message was clear: the money for the project would be better spent on architectural design components and interior finishes that would attract high-end tenants and entertainment seekers. The foundations, however, were challenging. The sheer size of the Xanadu development, the varying depths to rock, the loading conditions associated with the different structures, and the construction sequencing required the use of multiple deep foundation types and specialty foundation contractors. Xanadu, when completed, will consist of over 2.5 million sq ft of entertainment venues, restaurants and retail stores; America’s first i n d o o r s n o w dome; North America’s tallest (287 ft high) Ferris wheel; and four parking decks. Finished grades for Xanadu were essentially within about 1 to 2 ft of existing grades at the site, except for a 5 acre wetlands area, which received about 8 ft of new fill. Before the current construction, the approximate 75-acre Xanadu site was occupied by the Continental Airlines (now Izod) Arena, on-grade parking lots and the wetlands area. The Arena property is part of the New Jersey Sports and Exposition Authority (NJSEA) Meadowlands Sports Complex, which also includes Giants Stadium and the Racetrack, and is located in East Rutherford, N. J. Subsurface ConditionsThe site subsurface conditions include fill materials underlain by organic silt and peat (former marsh deposits or “meadowmat”), varved clay, glacial till and shale bedrock. The Xanadu site had been a marsh until the Sports Complex was created by filling in the early 1970s. The fill consists of dredged materials from Lower New York Harbor imported by hydraulic pipeline from the Hudson River. The fill also includes “historic fill,” defined as nonindigenous material deposited to raise the topographic elevation of a site, such as construction debris and other nonhazardous solid waste, and was generally encountered in thicknesses ranging from 8 ft to 18 ft. Within the previously developed portion of the site, a layer of marsh deposits consisting of peat and organic silt was encountered beneath the fill in thicknesses ranging from two ft to seven ft. Within the existing wetlands area, the marsh deposits were up to 10 ft below existing grade. The varved clay stratum was six ft to 36 ft thick. The depth to shale rock increases from approximately 15 ft near the west side of the site to approximately 80 ft near the south side. Groundwater was tidally influenced and varied from about 6 to 12 feet below both existing and proposed grade."

Jan 1, 2009

By Tom George

"INTRODUCTIONNo. 1 Queens Rd was an existing 10-storey office building founded on large pad footings. This project involved the construction of a 6-level, 15m (50-ft.) deep basement excavated immediately adjacent to the existing building and also beneath the existing footprint of the Southern end of the building. The total perimeter of the new basement was to be approximately 200m (656 ft.) all with a retained height of 15m (50 ft.). It was also proposed to add a further 5 storeys to the building. Approximately 18 of the existing columns supporting the 10-storey building were to have the applied column load diverted from the existing foundations at ground level onto the new piles or basement raft 15m (50 ft.) below.The geotechnical profile consisted of fill for the top 1.5m predominately comprising of clayey sand with a high gravel content from 1.5m to 9m (5 to 30 ft.), a medium dense to dense clayey sand and then below was a sandy clay extending to 15m (50 ft.) ranging from stiff to very stiff. From 15m on completely to extremely weathered siltstone was encountered. The groundwater was measured at 9.5m (31 ft.) below the natural ground surface.DESIGN BRIEFThe existing building columns were founded on large pad foundations up to 4.4m (14.5 ft.) square, founded on the dense clayey sand. These pads would require temporary support to enable the excavation to proceed beneath them. Upon completion of the excavation under the pads new columns were to be constructed joining into the existing columns to transfer the load onto the new raft slab, 15m (50 ft.) below. The existing 10 floors were to be refurbished. It was planned to undertake all the temporary support and transferring of loads while the structure above was only able to provide a dead load. It was decided that any movement of the building would have minimum impact on a skeleton structure. During the temporary support of the columns, movements due to construction activities had to be monitored to understand any potential stresses in the structure above.The original design required beams to be installed under the pads and supported at either end by temporary piles that were to be founded below the level of the proposed excavation. (Refer to sketch 1). Wagstaff Piling considered that this methodology had difficulties in construction at all stages and did not provide facility for transfer of the load without significant movement of the structure above. Wagstaff Piling revised the design to attach beams to the columns above the pads using shear collars. (Refer to sketch 2). These beams supported on the temporary piles could then be jacked upwards to remove loads off the pads. This would enable removal of the pads with minimal movement of the 10-storey building above. (Refer to photo 1 and back cover photo)."

Jan 1, 2005

"What can we do in ground engineering to reduce damage to the environment, to repair historic pollution, to reduce our demand on basic resources and to reduce the carbon footprint of our industry? Some developments in geotechnical engineering are already heading in the right direction. These include reductions of ground pollution from grouting, improved dewatering procedures and advances in mix-in-place processes, ground improvement and jet grouting.There is increased interest in certain promising technologies (for example, drilled partial or full displacement piles), but this approach remains for the moment somewhat avant-garde. These piles require substantially greater power to install, and the overall sustainability balance for general application has yet to be shown to be in their favour. They are particularly suited to polluted sites where the problem of dealing with spoil would be costly and where, in the past, driven cast in-situ piles would have been employed. Drilled displacement piles offer some environmental benefit over driven piles in that they cause far less drawdown of potentially contaminated near-surface ground into sensitive, underlying aquifers.There is also great interest in various means of increasing the frictional capacity of bored piles, both conventional auger and continuous flight auger (CFA) piles, by threading or ribbing the soil/pile interface. The increase in adhesion capacity allows reduction in the pile dimensions necessary for a specific load. This obviously leads to less construction waste, but also to less permanent material consumption in the piles and also in the pile caps.The role of ground improvement remains significant for brown land sites and lower capacity foundations. Information technology (IT) has improved the quality assurance of stone column construction, for example. From the sustainability point of view, this is a good news method; here is no cement, no pollution and little obstruction to future redevelopment. We now need to introduce recycled crushed materials instead of natural aggregate as general practice and the technique’s green credentials will be really compelling."

Jan 1, 2009

By Sanjay Gupta, Sorabh Gupta, Ravi Sundaram, Abraham Varghese

"Geotechnical investigation for the Kochi Metro revealed a critical section of the Viaduct near Ernakulam Junction Railway Station. Four piers, located over a 220 m stretch, were passing through an area with substantial thickness of soft clay. The scope of the geotechnical investigation included two boreholes and a static cone penetration test at each pier location. In the boreholes, field vane shear test was conducted at different depths in addition to the routine SPT. The design of heavily loaded piles in such strata is a challenge due to the liquefaction of the shallow sands and negative skin friction / down-drag in the soft under-consolidated clay. Bored cast-in-situ piles of 1500 mm diameter extending to 50-60 m depth were used to carry 500-600 tonnes load.INTRODUCTIONThe first phase of the rapid transit system at Kochi, Kerala (See Fig. 1) whose elevated route spans from Aluva to Thripunithura covers a total distance of about 25 kilometers. One of the more critical sections of the viaduct exists near the Ernakulam Junction Railway station where the alignment takes a sharp curve to move towards Vyttila, crossing the railway tracks and running partially over the approach of South over-bridge.In this section, four piers located on either side of the railway tracks near the Route Relay Cabin of Ernakulam Junction Railway Station pass through an area with substantial thickness of soft underconsolidated clay.The alignment is geotechincally challenging due to the presence of loose liquefiable sand and soft underconsolidated and sensitive clay.Initial investigations by the owner based on limited boreholes only yielded conservative and inconclusive pile capacities. For a thorough understanding of the soil behaviour, a detailed geotechnical investigation was carried out to assess the engineering behaviour of the soil strata.The scope of the geotechnical investigation included two boreholes and a static cone penetration test at each pier location. In the boreholes, field vane shear tests were conducted at different depths in addition to the routine SPT."

Jan 1, 2015

By Viswanadham B. V. S., Babu K. V

Many refineries are in the process of revamping and expanding their existing facilities. Most of the refineries are located in coastal areas due to ease of transportation and storage of crude oil. Considering the criticality of structures as well as prevailing soil conditions, most of the structures are supported on pile foundations. In depth review of sub-surface investigations data followed by liquefaction assessment of the site, it is noticed that site is prone to liquefaction during the seismic event. Among various techniques, driven cast-in-situ piles were selected to mitigate liquefaction. Static cone penetration tests were conducted during the pre and post installation of driven cast-in-situ piles at identified locations. Analysis of cone penetration test data shows that considerable ground improvement has been achieved post-installation of driven cast-in-situ piles.

Sep 1, 2022

By Richard Brink, Eric M. Klein, Kenneth B. Andromalos

"A portion of the roof for a 129 x 144-inch, nearly 100-year-old sewer outfall in the City of Baltimore had deteriorated to the point that it resulted in the development of a large sinkhole in a residential neighborhood. A subsequent video inspection of the sewer outfall indicated that there was a hole in the sewer outfall, and it would need to be repaired . After initial backfilling of the sinkhole and repairs to the water service lines, a conventional wood shoring system was used to support the excavation and expose the Main Outfall Sewer to inspect and repair it. This excavation was unsuccessful because of loose sandy soils and high groundwater conditions. An innovative use of a steel reinforced jet grout excavation support system was ultimately used to underpin an adjacent 20-inch water main and other nearby utilities, and provide access to the top of the Main Outfall Sewer some 22 feet below the street surface to facilitate inspection and repair of the sewer. This excavation support system was also successfully utilized in the final repair of the sewer roof by serving as a buttress for the new roof system.1.0 IntroductionThe project site is located in a residential neighborhood with brick masonry row houses situated on the south side of Chase Street and a brick masonry church on the north side of the street. Figure 1 illustrates the location of the site. The City right of way is 65 feet wide, and the street is 40 feet curb to curb. The centerline of the Main Outfall Sewer runs parallel to and a few feet south from the centerline of the street. Other utilities running parallel to the street include a cast iron 20-inch water line built about 1910, a 24-inch terra cotta storm drain, a 6-inch terra cotta sanitary sewer, a 4-inch cast iron gas line and a 40-inch electrical duct. Cross utilities included a 4-inch gas line and several smaller water and gas service lines to the church and row houses. One gas line that was not shown in the City's GIS database was exposed during the excavation."

Jan 1, 2005

By M. Melih Demirkan, Juan J. Gutierrez, Raghav Ramanathan

"As the capital of the United Arab Emirates (UAE), Abu Dhabi is one of the world’s fastest-developing cities. To sustain its significant growth rate, Abu Dhabi must surmount challenging engineering problems in the most efficient manner. One of the challenges facing Abu Dhabi is ground settlement caused by poor groundwater control practices in inherently difficult subsurface conditions. For construction projects in Abu Dhabi located near the Arabian Gulf, groundwater is frequently encountered and must be accounted for and addressed during design and construction. Abu Dhabi City CenterRecently, the Abu Dhabi government developed a geodatabase by digitizing, processing and qualifying an extensive amount of existing information (i.e., more than 26,000 borehole logs). Because of the evaluation and processing of the geodatabase, detailed maps of geotechnical and hydrogeological surface features were generated using 3D modeling. Ultimately, the geodatabase was used to develop risk maps indicating geohazards, such as sabhka (or salt flats), uncontrolled fill and cavities. This information identifies the location and extent of the areas vulnerable to surface subsidence. Dewatering can change pore water pressure, which, in turn, alters the effective vertical stress in a soil mass and can affect groundwater chemistry. Changes in pore water pressure and groundwater chemistry can significantly affect soil and rock. The potential effects of dewatering include:• Change in effective stresses and shear strengths in soils• Increase in seepage velocities and pressures• Erosion or transport of soil particles and piping• Settlement• Collapse of subsurface cavities or voids• Transport of groundwater containing contaminants• Dissolution of soluble materials, such as rock salt or gypsum"

Jan 1, 2017

By Robert Bachus, Jamey Rosen, Fabio Santillan, Georgette Hlepas

"A seepage barrier of length 4,800 feet and maximum depth 144 feet is being installed at Bolivar Dam in Ohio. This project is owned by the United States Army Corps of Engineers and contracted to Treviicos South. Many data types are being collected, synthesized and analyzed on a nearly real-time basis to monitor and track dam construction using several technologies including an enterprise relational database and web-based Geographical Information Systems. These data are being collected by both the owner and contractor and managed by the data subcontractor, Geosyntec Consultants. Each of the owner and contractor brings their own list of goals and desires to the data management program, and the subcontractor’s duty is to address these goals with minimal compromise by either party. The owner requires comprehensive, transparent and timely access to data in both “executive summary” and detailed formats. The contractor requires immediate analysis of disparate data to determine (for example) if a given excavation meets the specified tolerance and continuity requirements. This paper will describe the tools and methods used to store, analyze and visualize these data and discuss how each party’s needs were met in a collaborative system.INTRODUCTIONThe 4,800 foot long seepage barrier under construction at Bolivar Dam requires the collection, organization, and sharing of several types of data. These data include drawings and borehole logs that existed prior to construction; data collected during construction (seepage barrier panel composition and verticality data, slurry quality control and quality assurance data, grouting records, etc.); and instrumentation data collected and reviewed throughout and beyond construction. Each of these data streams require input and review from the Owner (United States Army Corps of Engineers (USACE), responsible for quality assurance and the ultimate consumer of the data), the Contractor (Treviicos South, responsible for the construction of the seepage barrier, its quality control and analysis of the data per the Contract Specifications), and the Data Management Subcontractor (Geosyntec Consultants, responsible for organizing and presenting the data to meet the needs of the Owner and Contractor). While all parties work with the same common goal, i.e.: producing a high quality product in an efficient manner making dam safety paramount during construction, and require immediate and comprehensive access to these data, the needs and desires of the parties differ. The challenge presented to the Data Management Subcontractor is to synthesize these data into a series of tools and reports that meet each of these needs."

Jan 1, 2017

By Ryan P. Sullivan, G. Alan Klevens, Jian Huang

"BACKGROUNDLake Hamilton in Hot Springs, AR was created in 1932 when the Arkansas Power and Light Co. completed Carpenter Dam on the Ouachita River to generate electricity. Today, the 7,200-acre (2,914 hectares) impoundment is one of Arkansas’s most popular recreational and residential lakes.U.S. 70 crosses Lake Hamilton by means of a seven-span bridge featuring nine steel girders per span. Constructed between 1982 and 1984, the 1,410-foot long (430m) bridge carries four lanes of traffi c across the lake. The bridge is supported by six intermediate reinforced concrete piers composed of hammer heads, stems, footings and seals, which sit on the underlying rock. (See Figure 1). The bridge rises to a maximum of 33 feet (10m) above the surface of the lake and the footings and seals extend a maximum of 29.5 feet (9m) below the surface of the lake. The seals are situated on hard, fractured sandstone and shale.Routine underwater inspections in 1993 revealed large cracks in the lean seal concrete and refl ective cracks in the reinforced concrete footings. Infrastructure Engineers, Inc., The Arkansas State Highway and Transportation Department’s (AHTD) design consultant, then conducted an in-depth underwater inspection of the pier foundations. The investigation included cross-hole sonic logging, singlehole sonic logging, visual examination and strength testing of core samples, and petrographic analysis.The investigation revealed extensive cracking and low-strength concrete within the seals of all intermediate pier foundations. Many voids within the seal concrete had become fi lled with silt. There was evidence of continued seal deterioration between underwater inspections.AHTD and its engineers considered three rehabilitation solutions in the preliminary engineering stage: micropiles, a cofferdam supported concrete jacket, or a pile supported concrete jacket. The three alternatives were estimated to cost $1,250,000; $4,320,000; and $3,030,000 respectively. All three options would transfer the loads from the pier footing directly to the rock below, bypassing the seal concrete."

Jan 1, 2007

By Ryan P. Sullivan, G. Alan Klevens, Jian Huang

"BACKGROUNDLake Hamilton in Hot Springs, AR was created in 1932 when the Arkansas Power and Light Co. completed Carpenter Dam on the Ouachita River to generate electricity. Today, the 7,200-acre (2,914 hectares) impoundment is one of Arkansas’s most popular recreational and residential lakes.U.S. 70 crosses Lake Hamilton by means of a seven-span bridge featuring nine steel girders per span. Constructed between 1982 and 1984, the 1,410-foot long (430m) bridge carries four lanes of traffi c across the lake. The bridge is supported by six intermediate reinforced concrete piers composed of hammer heads, stems, footings and seals, which sit on the underlying rock. (See Figure 1). The bridge rises to a maximum of 33 feet (10m) above the surface of the lake and the footings and seals extend a maximum of 29.5 feet (9m) below the surface of the lake. The seals are situated on hard, fractured sandstone and shale. Routine underwater inspections in 1993 revealed large cracks in the lean seal concrete and reflective cracks in the reinforced concrete footings. Infrastructure Engineers, Inc., The Arkansas State Highway and Transportation Department’s (AHTD) design consultant, then conducted an in-depth underwater inspection of the pier foundations. The investigation included cross-hole sonic logging, singlehole sonic logging, visual examination and strength testing of core samples, and petrographic analysis.The investigation revealed extensive cracking and low-strength concrete within the seals of all intermediate pier foundations. Many voids within the seal concrete had become filled with silt. There was evidence of continued seal deterioration between underwater inspections.AHTD and its engineers considered three rehabilitation solutions in the preliminary engineering stage: micropiles, a cofferdam supported concrete jacket, or a pile supported concrete jacket. The three alternatives were estimated to cost $1,250,000; $4,320,000; and $3,030,000 respectively. All three options would transfer the loads from the pier footing directly to the rock below, bypassing the seal concrete."

Jan 1, 2007

By Dena Morgan, Emre Biringen

"Abstract This paper discusses the execution of pile installation and design issues at two environmentally challenging industrial sites in North America. Environmental regulations set constraints on the design and require versatility in choice of technology.For a proposed bridge, due to protected fish habitat, performing soil borings within 30 m of the creek embankment was prohibited. The limited subsurface profile indicated a thick upper layer of granular material, thus driving H-piles was considered. However, to limit generation of vibration and noise in the protected area, drilled piles had to be used. During execution, the subsurface profile differed from that in the borings 30 m away. Very soft, saturated silt was encountered at the bottom of the caisson and the length had to be redesigned very quickly while the contractor waited for instruction. For a new structure in uncontrolled fill area, performing soil borings was not allowed. It was known that a layer of peat was present in the area, but no information regarding the thickness and extent. The subsurface profile generally consisted of granular material overlying a thick compressible silt layer. Somewhere within the granular layer peat would likely be encountered. Franki piles were chosen to penetrate the peat and bear in the underlying granular material. During environmental sampling in the area, methane gas was encountered and Franki piles were no longer a viable option due to safety concerns. The foundation system was changed to steel H-piles driven to bedrock, which was more than 50 m below the ground surface and sloping. Rock shoes that would work to significant slopes had to be used in order to increase the likelihood of good embedment within the bedrock. Also, due to obstruction of an approximately 3 m thick debris field that was encountered in the upper granular soils, some of the piles had to be relocated and extra piling needed to compensate for such differences. The results of PDA testing to estimate compressive capacity and a series of lateral load tests are presented.INTRODUCTIONThe design issues that are encountered during construction can be quite problematic and have a significant impact on schedule. In order to avoid such impact on the project, a thorough subsurface investigation should be considered prior to design and construction. Better understanding of environmental regulations also prevents costly changes to the foundation design. This paper discusses the execution of pile installation and the design issues at two environmentally challenging sites in North America.BRIDGEDuring the subsurface investigation for a proposed industrial building complex, several boreholes were drilled within the footprint or in close proximity of various structures, with Standard Penetration (SPT) sampling of the upper coarse-grained soils (sand/gravel) and undisturbed sampling of the lower fine-grained soils (silt/clay). The SPT blow counts (N60) were corrected by a factor of 1.35 in order to incorporate the SPT automatic energy transfer ratio. When Modified California Sampler was used, a correction factor of 0.44 to 0.64 was also applied. N60 values were further corrected for gravel to avoid artificially high blow counts during the analyses due to spoon samples contact with gravel and cobbles, and the corrected values of (NG)60 (limited to a maximum value of 50 blows/300 mm) were used for design. The information from the SPT boreholes was then used to assess the subsurface conditions beneath the structures, as well as for a nearby bridge that was designed to cross over a creek. Since performing soil borings within 30 m of the creek embankment was prohibited due to the protected fish habitat, the investigation with regard to the bridge abutments was limited to two deep boreholes (B10-33 and B10-34) at the bridge location and two additional boreholes (B10-35 and B10- 36) located approximately 200 m upstream. The bridge location and two sets of boreholes are"

Jan 1, 2014

By Nathan W. Iverson, David S. Graham, Paul J. Axtell

"The Highway 53 relocation project in Virginia, Minnesota, involves construction of a very tall bridge across a currently inactive iron ore mine pit. The inactive pit is partially flooded and serves as the community’s drinking water source. The 1,132-ft long new bridge is a three-span, plate girder structure. Two intermediate, approximately 200-ft tall piers are located within the pit.The foundations for the two piers consist of groups of 30-in diameter piles which, despite the contradiction in terms, are essentially very large micropiles. Extremely challenging and highly variable subsurface conditions exist at the site, ranging from uncontrolled iron ore mine waste fill to some of the hardest rock on earth that can also be highly fractured and abrasive. Despite the conditions, large diameter (30-in) micropile foundations up to 175 ft deep were successfully installed using down-the-hole hammer methods and full-length permanent casing under an extremely aggressive construction schedule.Full-scale foundation load testing using the Statnamic rapid loading method was also conducted in support of the design and construction but under a separate pre-design phase contract. This paper describes the unique aspects of this foundation project, including design, construction, and load testing of the large micropiles.INTRODUCTION AND BACKGROUNDIn 1960, a segment of Trunk Highway 53 (TH-53) in Virginia, Minnesota, was built on land owned by iron ore mining interests. As part of the roadway easement agreement, Minnesota Department of Transportation (MnDOT) was to be given notice three years prior to termination of the easement. In 2010, MnDOT received notice that the mining interests wished to access the ore. Through negotiations in 2010, MnDOT and the mining interests agreed to a 2017 date for abandoning the existing section of roadway. During this period, MnDOT needed to procure project funding, satisfy environmental permitting requirements, and acquire new right-of-way to permanently reroute TH-53 and keep it open to traffic. This was no easy task due to the existing mine pits surrounding the area.The E-2 alignment option shown in Fig. 1 was ultimately selected for the rerouted highway in 2014. The new highway segment includes a three-span bridge across the currently inactive Rouchleau Mine Pit. The inactive pit is partially flooded and serves as Virginia’s drinking water source. The 1,132- ft long new bridge is a three-span, plate girder bridge. Two intermediate approximately 200-ft tall piers are located within the pit. Fig. 2 is a conceptual rendering of the bridge."

Jan 1, 2017

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 Richard D. Luark, Fernanda S. Madrona

Designing temporary retaining systems that allow for deeper excavation amid the existing urban infrastructure has become a challenge. A 60-foot-deep excavation in downtown Seattle was required to construct five levels of below grade parking for a 35-story high-rise building, Tower 12, next to an existing 20-story tower with three levels of below grade parking, separated from the project by an 18-foot wide alley. The solution was to combine two temporary excavation support systems, soil nailing and anchored soldier piles, to work within the site constraints. Densely-arranged, short-length soil nails were used to support the upper 30 feet of the excavation, while the lower 30 feet of the excavation was supported with soldier piles combined with steeply-inclined, high-capacity ground anchors, which extended below the adjacent building foundations. The combined temporary support system eliminated the need for internal bracing, reducing construction cost and schedule. The performance of the combined soil nail and soldier pile system was monitored with an inclinometer and optical survey monitoring, which demonstrated the performance of the combined temporary support system. This paper provides a discussion of the advantages of combining different excavation systems and an analysis of movement monitoring data collected. SITE CONDITIONS AND PROJECT INFORMATION Tower 12 consists of a 0.45-acre development with 36-stories of mixed, residential and commercial use with four levels of below grade parking. The project site is bounded by the Cristalla Condominium to the north, Virginia street to the south, 2nd Avenue to the East, and an 18-foot wide private alley to the west. The One Pacific Tower Condominium, which has three levels of below grade parking, was located to the west across the alley. A site layout plan is presented as Figure 1. As shown in Figure 1, the construction of the west wall required a maximum 51-foot-deep excavation, from elevation (EL) 162 feet to EL 111 feet. Adjacent to the west wall, the existing alley grade varies from elevation 154 to 161 feet, leaving a narrow block of soil 18 feet wide and up to 42 feet high to be shored along the alley in order to reach the One Pacific Tower bottom of mat foundation at EL of about 120 feet. In addition to the existing One Pacific Tower Basement wall, site constraints included existing utilities along the alley such as an existing 4.5-feet wide by 7-feet high vault, with bottom at approximate EL 146 located 10 feet from the back face of the proposed Tower 12 basement wall.

Jan 1, 2019

By Takefumi Takuma, Tsunenobu Nozaki, Masashi Nagano

Using sheet piles and pipe piles for permanent earth retaining is one of the most economical methods for constructing basement walls since they can also work as temporary shoring during construction. A major mixed-use redevelopment project in the UK, encompassing two to three large city blocks, utilized both sheet and pipe pile walls for a two-level subterranean parking structure. The 290m (950ft) x 100m (330ft) basement’s steel walls were designed to temporarily support excavation during construction and eventually to become a load carrying permanent structure in order to expedite the construction process and to achieve cost reduction. Two types of press-in piling machines, one for sheet piles and the other for pipe piles, were used for the job because of their abilities to press in sheet and pipe piles within tight tolerances for finished walls, for difficult installation conditions with very hard soil, and for its very low noise and practically zero-vibration operation; an essential factor for the job in close proximity to other businesses and residents. BACKGROUND Steel sheet pile and pipe piles have been used for many purposes including earth retaining. They are produced at steel mills and spirally welded at a fabrication yard to their corresponding specifications under strict quality control measures. Therefore, they can form highly reliable walls to its design capacity with proper installations. Their advantages as underground walls are:  They can form a high level of water cut-off function with their interlocks sealed by welding or with hydrophilic materials. See Figure 1 for a few examples for a sheet pile application.  They can carry vertical loading in addition to horizontal load and bending moment.  They can be a self-standing and temporary/permanent wall with flexible design and construction processes; bottom-up, top-down or hybrid sequences can be chosen per the project’s needs.  They can form a thinner wall than other wall types, creating larger inner space. See Figure 2.

Jan 1, 2019