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By Ramin Motamed, Fahim Bhuiyan

Damage dealt with by some recent major earthquakes has raised concerns among the geotechnical engineering community to delve more into the area of soil liquefaction. As part of research funded by Pacific Earthquake Engineering Research (PEER), a large-scale shake table test on a laminar soil box was carried out at the University of California, San Diego, to investigate the effect of liquefaction-induced ground motion on a shallow foundation. In this study, a 2D numerical finite difference simulation of the baseline test was conducted in FLAC using the PM4Sand plasticity model. Some general behavior of sand layers during liquefaction including generation of excess pore water pressure, development of shear and volumetric strain, and their relative contribution to the total settlement were investigated. The model predicted the average final foundation and free-field settlements to be 21.94 cm (measured value 26.05 cm) and 12.36 cm in heave (measured heave value 1.57 cm) respectively. The shear strain appeared to govern the total settlement during seismic excitation compared to volumetric strain, during strong ground motion, while the latter became more apparent after the ground motion had subsided.

Oct 31, 2023

By Greg Stokkermans, Jim Hansen, Mary Kate Dempsey, Mark Reinders

The City of Toronto is reshaping and revitalizing its waterfront in the largest ongoing urban redevelopment project in North America. The redevelopment includes naturalizing the mouth of the Don River, which has become a source of flooding as the city has been built around it. Constructing a new river valley to alleviate this bottleneck involves multi-staged excavations up to 7 meters below Lake Ontario in permeable alluvial sands. In order to place a protective environmental barrier, these excavations need to be dewatered and require cantilevered earth retention over 6 meters high. This paper highlights the rapid design and construction of a 1.1-kilometer-long, up to 45-meter-deep secant pile cutoff wall that was constructed to support the first phase of excavation and dewatering of the new river valley. The paper discusses the geotechnical investigation and seepage analysis, selection of wall type, verticality criteria requirements, and construction challenges associated with the deep secant pile cutoff wall. Data collected during construction confirmed that the cutoff wall met critical design objectives and allowed for successful construction of the new river valley.

Oct 31, 2023

By Mangtao (Monty) Du, Brendan Busi, Patrick Bassal, Daniela Zellers

The Living Breakwaters project aims to reduce the impact of climate-intensified events on a coastal community which experienced extremely damaging waves and tragic loss of life during Superstorm Sandy. The project consists of approximately 2400 linear feet (730 linear meters) of near-shore breakwaters that will attenuate waves, reduce erosion, and provide habitat spaces for local marine life along the south shore of Staten Island, New York, USA. The system consists of eight rubble mound breakwater structures with a stone core, a base layer (bedding stone or marine mattresses) and outer layers of armor stones. This paper discusses geotechnical subsurface conditions, design, and construction of the breakwater system. The geotechnical design was predominately governed by global slope stability analyses. These analyses considered dynamic wave loading and wave induced excess pore pressures for the design storm event, as well as pseudo-static seismic loading and liquefaction evaluations. Several construction challenges were encountered with the fabrication and deployment of marine mattresses and underwater geotextile installation.

Oct 7, 2024

By Kurt Breitenbucher, Jeffery Schwarz, Bruce Wagener

Metropolitan Council Environmental Services (MCES) owns and operates nine wastewater treatment plants and 640 miles of interceptor pipeline to serve 111 communities and 2,700,000+ people in the 7-county Minneapolis/St. Paul metro area. Approximately 34 miles of interceptor pipeline, constructed of granite paving block invert, limestone block walls, and an unreinforced cast-in-place concrete arch, are installed within deep tunnels excavated through the soft, friable St. Peter sandstone formation. Some tunnels date back to the 1880’s. To maintain the integrity, reliability, and capacity of the interceptor system, be better prepared for the effects of climate change, and prevent potential damage to the environment due to pipe failure, MCES partnered with Brierley Associates to develop a sandstone tunnel inspection program utilizing historical records and desktop likelihood/consequence risk analyses to prioritize work. This assessment aimed to rank the interceptors by risk priority and provide a framework for MCES to develop projects and improve resiliency. A major challenge in assessing a system of this size is its relationship to adjacent infrastructure. Much of this system was built on vacated right-of-way or through areas not yet heavily developed when the interceptor system was constructed. In other cases, the interceptors had to adjust for natural features such as the Mississippi River's bend or caves. Across the miles of interceptor sewers are multiple encroachments with building foundations, MnDOT tunnels, and bridge foundations, and a cave with columns transferring loads from overlying buildings.  In several segments, it was identified that sandstone slabs had fallen on the interceptor with significant voids above the tunnel crown.  The sandstone(sand) would then enter the interceptor through openings. The voids were filled with grout to reduce deterioration and mitigate sinkhole development. MCES then partnered with CNA Consulting Engineers to devise inspection methods to observe the tunnel liner condition and to locate voids by drilling from above and around the tunnels. Results of the inspections are being used to develop rehabilitation plans, direct capital project expenditures, and enhance system resiliency. 

Oct 7, 2024

By Alan Walka, Paul Deterling

The existing B and D wings of the Somerville High School in Somerville, Massachusetts, were required to be underpinned to allow for additions to and a large expansion of this facility. A combination of micropiles and soil nailing was designed by Earthwork Engineering and Hub to provide both structural underpinning of the existing foundations and lateral support for both the structures and the soils below the foundations. The depth of the exca­vation was up to 25 ft (8 m) below the existing foundations.

Sep 1, 2024

By Ed Laczynski

Traveling from Maine to Florida, I-9S is the U.S.' longest North-South interstate and has been growing and expanding through the Mid-Atlantic. In Maryland, the 1-9S Express Toll Lanes projects created new toll lanes to relieve congestion and increase quality of life for numerous communities along the interstate, according to project owner, the Maryland Transportation Authority (MDTA). Many of these projects also included replacing or rehabilitating bridges and constructing new noise walls, as well as retaining walls, as I-9 S expands to accommodate the new lanes. The focus of this article is the 1-9S Express Toll Lane Northbound Extension from MD 43 to south of MD 1S2. This project contains 11 large retaining walls with some of these walls combined with noise walls. Many of these projects join other adjacent 1-9S toll lane expansions, which makes timing critical and scheduling very important. In this particular project, all of the major retaining walls were on one side of 1-9S and built in one phase that created scheduling and logistical challenges.

May 1, 2024

By Casey D. Shanahan, Dustin Walkenhorst

The Howard Frankland Bridge megaproject consists of a new, 3.2-mile (5.1 km) bridge extending I-275 across Tampa Bay. Two steel sheet pile and combi-wall bulkheads with a total wall length of over 11,000 ft (3350 m) were required to create the land for the new roadway and bridge approaches. A total of 1,287 permanent grouted soil anchors supports the bulkheads, which in some areas retain a 20-ft (6.1 m) tall MSE embankment. Anchors with lengths up to 200 ft (60.1 m) were installed, and project design loads necessitated anchors that varied from 3-strand to 8-strand. The soil conditions at the site were typically loose to dense sands underlain by a thin layer of clay over karstic limestone of variable hardness. Given the magnitude of the design loads, the larger anchors were designed to bond into limestone. Limestone variability along the bulkheads was observed. In some extreme cases, the top of the limestone elevation varied by nearly 100 ft (30.5 m), which created challenges for designing the length for anchors that were required to bond into limestone. Given the proximity to Tampa Bay, most of the work was performed from a barge. Waler systems were installed on the waterside of the sheet piles, so installation and welding work was limited to lower tide stages. The geotechnical contractor designed and installed the anchor and walers systems to fit within the proposed concrete cap. The objective of this paper is to discuss the significant design and installation challenges of the anchor and waler system for this high-profile project.

Oct 31, 2023

By Derek Egbert, Kevin Baumgartner, Howard Perko

Foundation designs in a bid-build business environment can be challenging as so much depends on the capabilities of the selected contractor.  Owners and governing agencies must be open to value engineering (VE) alternatives.  This paper presents a case history where a foundation VE design was prepared for a county bridge replacement. The existing structure was a two-lane, simply-supported, truss bridge approximately 270 ft long and 30 ft wide.  The new bridge is a three-lane, two-span, continuous steel plate girder bridge approximately 250 ft long and 49 ft wide.  The new bridge was to be founded on two end abutments and one center pier by a total of 173 micropiles. Due to the number of micropiles and the time requirement to install a single micropile, an alternative design was proposed utilizing driven steel piles for support of the abutments and rock-socketed drilled shafts for the center pier. Replacing the micropiles with the proposed alternative was intended to reduce overall construction time and cost. Shallow bedrock and soil scour presented unique challenges for the bridge foundation and required an in-depth investigation to determine the required depth of foundation elements to achieve pile toe fixity. It was determined the sand layer thickness was not sufficient in some places to provide fixity to the VE driven piles and therefore the east abutment had to remain the original micropile design.  Substitution of driven pile and rock-socketed drilled shafts in the other areas still resulted in both time and cost savings.  This case history shows how engineers, contractors, owners, and governing officials can collaborate collectively to develop effective foundation solutions. Keywords: micropile, driven pile, drilled shaft, abutment, center pier        

Oct 7, 2024

By Steve Babcock, Howard Perko

Since the development of the ICC-ES AC358 acceptance criteria, the use of helical piles as deep foundation solutions has grown in popularity and expansion of desired applications. With this has come a desire to use larger diameter shafts to support larger loads. Helical piles employ a unique method to predict performance by correlating the final installation torque to the ultimate load carrying capacity for both tension and compressive loads. This capacity-to-torque factor is commonly denoted as the ‘Kt’ factor. Previous publications from multiple authors have estimated the capacity-to-torque relationship both empirically and theoretically for helical piles.  Most of these prior studies focused on smaller shaft diameters from 1.5-inch square to 3.5-inch round.  Current trends have motivated the helical pile industry to utilize larger diameter pile shafts than are not well represented by the prior publications, including AC358. This paper presents an expanded body of empirical data comprised of full-scale load test results of helical piles with diameters ranging from 1.5 inches up to 18 inches. The curve fitting methods used to develop the AC358 equation are re-examined and offers an alternative that better fits the test data. The current methodology uses a simple exponential curve with a limit of zero as pile shaft diameter increases. This implies that at some point a helical pile’s diameter would become so large that it would have zero capacity, which is illogical. Utilizing a horizontal asymptote, other than zero, in the curve fitting analysis provides a better fit to the data.  The better fit increases to the capacity-to-torque ratio for larger diameter piles on the order of 15% to 30%.  Also, presented are some key insights that the authors offer for consideration in further development of this critical relationship.

Oct 7, 2024

By Brian Wilson, Franz-Werner Gerressen, Johannes Reinisch

Specifications for traditional auger mixing methods have made use of the Blade Rotation Number (BRN) to establish acceptable levels of mixing. Cutter Soil Mixing (CSM) has no such established parameter. Previous research has proposed the adoption of an Energetic Mixing Index for CSM and has attempted to establish a basis for this utilizing results from a limited number of panels. This paper reviews the basis of this previous proposal and assesses the applicability of the proposed index utilizing a review of production data from a number of sites in proximity to Vancouver, British Columbia, Canada. Based on the outcome of the review, the paper proposes adoption of a new index for initial field quality control of CSM operations.

Oct 31, 2023

By Charlotte Caton, Adam Dyer

Developing lands adjacent to environ­mental cleanup sites can come with a high construction cost. This is the case for many sites being developed around the highly contaminated Gowanus Canal, a Superfund site in Brooklyn, New York. One of the main challenges for construction near the Gowanus Canal is preventing contaminants from migrating into the sites and avoiding the cost associated with dewatering contaminated groundwater near the ground surface. Therefore, seldom are buildings around the canal designed to have a cellar. However, the unique development conditions at the 420 Carroll Street project site required a ceHar to be constructed in two buildings, 20 ft (6 m) below groundwater, with a tunnel connecting them, in a neighborhood where cellars below groundwater typically aren't built and where subsurface conditions are complex. The solution was a soil mix mass support of excavation system (SOE) with steel core beams for lateral support and drilled displacement piles for uplift resistance. A dry excavation up to 20 ft (6 m) below groundwater was accomplished at a distance of about 100 ft (30 m) from the canal.

Oct 1, 2024

By Ian Vaz, Taylor Stevenson, Takefumi Takuma

Taylor Stevenson, Blue Iron Foundations & Shoring LLC, Newport Beach, CA, U.S.A. Phone: (949) 933-9043, Email: taylor@blueironllc.com Chris DellAringa, Blue Iron Foundations & Shoring LLC, Newport Beach, CA, U.S.A. Phone: (916) 340-5600, Email: chris@blueironllc.com Ian Vaz, Giken America Corp., Orlando, FL, U.S.A. Phone: (407) 666-8119, Email: ivaz@gikenamerica.com Takefumi Takuma, Giken America Corp., Orlando, FL, U.S.A. Phone: (407) 907-4680, Email: ttakuma@gikenamerica.com, The Fullerton Creek Channel Phase 2 project undertaken by the Orange County Flood Control District stood out as an exemplary blend of innovation and environmental sensitivity. Tasked with stabilizing the channel banks, the project demanded an approach that mitigated noise and vibration, prompting the incorporation of the press-in piling method right from its conceptualization. This non-vibratory, minimal noise method of pile driving has revolutionized traditional piling techniques by significantly reducing environmental impact, making it an ideal choice for environmentally sensitive areas. Central to this unique method's success was Blue Iron Foundations & Shoring, entrusted with the press-in installation of 3,459 linear feet of PZC26 sheet piles, ranging from 38 to 45 feet in length. Leveraging their extensive equipment arsenal, Blue Iron utilized two of its Giken ECO 1400S press-in machines to install the sheet piles just mere feet away from existing structures. The utilization of 2 press-in machines enabled the simultaneous installation of both channel walls between April 24th and July 24th in 2019 to complete the project ahead of schedule. Despite very limited working space within the channel banks which made the project a challenge logistically, installation efficiency was still optimized without compromising the delicate environmental balance of the site which traversed through both residential and business areas. In conclusion, the Fullerton Creek Channel Phase 2 project showcased the fusion of groundbreaking technology and environmental consciousness. The adept utilization of the press-in piling method and cutting-edge equipment underscored the contractor's leadership in adopting innovative solutions while prioritizing environmental preservation in complex geotechnical projects.

Oct 7, 2024

By Spencer Waganaar, Katherine Winters, John Murphy

Hundreds of miles levees cutoffs have been placed in USACE levees in the Sacramento CA, Houston TX, and Southern Florida regions in the past 40 years, with smaller projects in additional regions. Many of these cutoff walls are designed for infrequent loading as they that are critical infrastructure for extreme flood events. With this infrequent loading, there are no widely accepted ways to monitor and quantify the condition and functionality of seepage cutoff walls for levees over multiple decades. The potential for deterioration is not well known. Lack of data on the longevity/design life of cutoff walls adds uncertainty to levee risk assessments, operational and maintenance costs, and community risk. USACE-ERDC is conducting a comprehensive review of existing research regarding cutoff wall longevity and deterioration to address these uncertainties. The potential mechanisms of deterioration are cracking, chemical reactions, vegetation growth, or animal burrows. This paper includes documenting experiences from USACE levee safety experts, pertinent failure mechanisms identified from engineering literature, whether and how these considerations for cutoff walls are currently incorporated into risk assessments, and assessing the need for need for further research to reduce uncertainty. The findings presented in this paper will include uncertainties and potential risks to levee performance due to levee cutoff wall deterioration and suggest areas for further field investigation. Findings could contribute to improving recommended potential post-construction QC practices, operations and maintenance practices, identifying early warnings of reduced functionality, reducing costly invasive/destructive testing, and informing risk assessment methodology.

Oct 7, 2024

By John McKinnon, Tony Barila, Ahmad Khatib

The 161 First Street project is an existing 4-story brick building, located in Cambridge, MA that underwent a complete renovation to allow for it to be utilized as an office building. The new addition will be supported by existing and new reinforced concrete columns supported by drilled micropiles (DMPs) at basement level. Alexandria Real Estate Equities, Inc. is the owner; Consigli was the construction manager; W. L. French was the site contractor; McNamara Salvia was the structural engineer and Haley & Aldrich was the geotechnical engineer. The existing and new reinforced column foundations will be supported by DMPs drilled from the basement, approximately 8’ below existing grade. A total of 163 DMPs, 87 with a compression design load of 160 kips and 76 with a compression design load of 40 kips, were installed. A pile load test was performed in tension to a maximum test load of 561.2 kips (3.5 x Design Load) to confirm the embedment length of the DMPs in the marine deposit and glacial till. Consgli invited Hub to participate with the project design team to evaluate the initial foundation design relative to the soil profile, logistics and construction schedule. The initial foundation support was a maze of helical piles. We evaluated several other piling options which were more cost-effective with less impact on concurrent construction activities and faster schedule. Ultimately, we recommended a micropile solution which was accepted by the project design team. The main challenges on this project were the low headroom, tight working space between the existing columns, the access to the work area via a single ramp and contaminated soils. The upper soils at this site were heavily contaminated. A novel drilling approach was utilized to ensure that the drill spoils in the upper 12ft were segregated from the soil below that depth. In addition, Hub utilized its Soil Separation System (SSS) to separate the water and soil from the wet drill spoils. This system allowed for the most efficient way to manage, collect, and dispose of the drill spoils within a low headroom application. The entire DMP scope was completed in four months. This duration was less than required by Consigli’s schedule. The DMPs were drilled with the Davey-Kent 515 and the Comacchio MC-4D drill rigs.

Oct 7, 2024

By Thomas Pullen, Gregory Spicer, Joe Welna, Lola Moussey

During the past several decades, a segment of Interstate 35W (I-35W) at 42nd Street, located in Minneapolis, Minnesota, has experienced flooding during intense storm events. Flooding is caused by a combination of runoff from the upstream watershed and backflow through the downstream stormwater tunnel system. The Minnesota Department of Transportation (MnDOT) evaluated several stormwater storage facility (SSF) concepts to mitigate flooding. The sub-grade storage tanks are located adjacent to I-35 WB, between the highway shoulder and 2nd Avenue, which is elevated approximately 25’ above the highway. Prior to construction, there was an embankment covering the footprint of the new storage tanks, which supported earth loads and provided base reactions for a soundwall running parallel to 2nd Avenue. Therefore, an earth retention system would need to be installed to permit removal of the embankment. The project team elected to build a soil nail wall, which was constructed in lifts as the embankment removal progressed. Notable challenges related to design and construction of the soil nail wall were as follows: (1) elevations and angles of the soil nails to avoid conflict with existing utilities on the backside of the wall, and (2) sound wall base reactions including separate load cases for wind load acting in each direction to determine the governing scenario for the retaining wall. Design and construction consisted of six underground storage cells approximately 80 feet deep and 42 feet in diameter. The cells were constructed using slurry diaphragm walls and depressurization which allows for handling a high groundwater table (approximately 10-15 feet below highway grade) and highly variable glacial outwash soils in a congested construction area. This paper will discuss the design and construction considerations for the soil nail wall and underground storage tanks.

Oct 7, 2024

By Kamil Nuzha, Jianchao Li, Bashar S. Qubain

A 52-story high rise building in Philadelphia is constructed adjacent to a 3-story historic structure, supported on a rubble foundation at a depth of 2.4 m (8 ft) below grade. The high rise is supported on a mat foundation at a depth 36 ft below grade with an average service contact pressure of 670 kPa (14 ksf). Evidently, the existing foundation requires underpinning but extra care is necessary to safeguard the historic building. A detailed finite element analysis showed that the mat foundation would settle about 38 mm (1.5 in). Although such settlement would be acceptable for the high rise it would cause intolerable distress to the historic building by dragging down its underpinning. To minimize the settlement impact, an innovative micropile solution was implemented to safely transfer the underpinning load into the underlying mica schist bedrock and prevent the existing building from being overstressed by the mat foundation. The specifics of the micropile pile design and associated details are presented herein. The new building was completed almost two years ago and the adjacent historic building has been functioning well without any signs of distress.

Oct 31, 2023

By Bernardo Jimenez

Earthquake-induced deformation of bridge piers underlain by liquefied soil may impose significant demands on the foundation system due to lateral spread. A relatively simple equivalent-static analysis (ESA) procedure can adequately predict the response of bridge foundations to lateral spreading. Typical procedures for ESA analysis assume a 'infinite-length' lateral spread feature, implying that further increases in size would not increase the demand placed on foundations within the spread. Recent studies have indicated that if the areal extent of the spread feature is smaller than the zone of influence, the displacement demand must be reduced to account for pinning effects. This case can be considered a finite-length spread. Additionally, a reduction in demand imposed on one foundation component may occur during a finite-length spread due to the shielding effect from an adjacent foundation. This document reviews and applies a method to evaluate finite-length spread while considering pinning and shielding effects. The selected bridge system is the Taras overpass in Costa Rica. By using two-dimensional finite element analyses (FEA) interaction with ESA results, pinning and shielding effects are accounted for and compared to ESA analysis for 'infinite-length' spread. The results indicate that for bridge piers accounting for a finite-length lateral spread can significantly decrease demands on the foundations during design phases.

Oct 7, 2024

By Mohammad Moontakim Shoaib, Murad Abu-Farsakh, Hani Titi

The evaluation of load-settlement behavior of piles is very crucial in meeting the serviceability criteria for pile analysis and design. The most reliable approach for estimating this behavior can be achieved by conducting pile load tests. However, due to the considerable expense and time requirement of such in-situ testing, the load-transfer methods have been used routinely in practice. In this paper, an alternative tree-based machine learning (ML) modeling is explored to predict the load-settlement behavior of axially loaded single piles from cone penetration test (CPT) data. Two variants of tree-based ML models, the random forest (RF) and gradient boosted tree (GBT), are developed in this study to estimate the load-settlement behavior of piles from CPT data (corrected cone tip resistance, qt, and sleeve friction, fs). A database of load-settlement curves of 64 static pile load tests and the corresponding CPT test data were compiled and used for the development of these ML models. The developed RF and GBT models are evaluated based on several statistical criteria. The load-settlement curves for six PLTs predicted using the developed RF and GBT models were compared with the measured data and the load-settlement curves predicted using the conventional load-transfer methods. The results demonstrated the great potential of tree-based ML (RF, GBT) models for predicting the load-settlement behavior of axially loaded piles from CPT data. The comparison clearly shows that the ML models outperformed the conventional load-transfer methods. Amongst the two ML models, the results show that the GBT model outperformed the RF model.

Oct 7, 2024

By Benjamin Giacometti, Adam Hacker, Enrique Farfan, Tom Pace

The Louisville Metro Levee System reduces flood risk to the City of Louisville, Kentucky. The levee system was constructed by the U.S. Army Corps of Engineers and is now operated and maintained by the local sponsor, the Louisville and Jefferson County Metropolitan Sewer District (MSD). The levee system has a total length of 26.1 miles, consisting of concrete floodwalls and an earthen levee with sixteen flood pump stations for flood protection.   MSD determined the need to upgrade the existing Paddy’s Run Flood Pump Station’s capacity to reduce the risk of interior flooding. Due to the age and complications associated with upgrading the existing pump station, a new flood pump station will be constructed within the existing levee prism and portions of the existing station will be selectively demolished. MSD initiated a Progressive Design-Build project for a new Paddy’s Run Flood Pump Station. The project proposed a diaphragm wall construction to serve as the temporary support of excavation for the new flood pump station, permanent foundation for the new flood pump station, levee under seepage cutoff, and embankment stability. The lateral soil pressures on the diaphragm walls result from the staged construction sequence, including the effects of bracing to provide lateral support to each wall, and soil-structure interaction. To properly account for these effects, Plaxis 2D models were created for different sections of the structures. The lateral soil pressures for the diaphragm wall design were obtained from the output of these Plaxis models. This paper and presentation summarizes the geotechnical aspects of the diaphragm wall design and how it was used to inform the structural design.

Oct 7, 2024

By Mirza Shafiq Ibrahim, Martin Hudson, Rishabh Singhvi, Saiful Islam

The Landmark Apartment building is a 34-story high-rise constructed in West Los Angeles. The high-rise was constructed within a portion of the footprint of an existing parking structure with four subterranean levels. The foundations of the new high-rise were cast-in-place drilled hole (CIDH) piles in order to limit settlement of the new construction relative to the existing parking structure spread footing foundations. In order to construct within the parking structure, a gloryhole had to be cut in the parking structure at the location of the new high-rise footprint, necessitating temporary bracing of the parking structure basement walls. The temporary bracing had to be accomplished using both tie-back anchors and internal bracing (rakers) in order to provide lateral restraint for the basement wall. The internal bracing required its own set of foundations, including micropiles and tie-back anchors to laterally restrain the micropile caps. The foundation system for the new high-rise had to be split into two major pile caps on either side of the temporary micropile cap foundation for the bracing system, with the temporary micropile cap tie-back anchors threading between the permanent structure drilled shafts. In addition, groundwater was located just beneath the bottom-most slab of the parking structure, requiring dewatering of pile cap excavations. With high groundwater conditions, drilling mud was required to install the CIDH piles. These design challenges were accomplished successfully and meeting the requirements for foundation performance and seismic performance of the structure. The multiple challenges of temporary works also required careful coordination of dewatering, shoring installation, and foundation installation among the various disciplines.

Oct 31, 2023