Search Documents

By J. David Frost, Anna Frost, Morgan NeSmith, Boyeong Yoon

The Leaning Tower of Pisa is recognized globally as a testament to resilience in that it has been leaning from early in its 800-year existence and yet is not considered a failure from many, if any, perspectives. If one asks the question, "Could foundation-based architecture have prevented it from leaning from the outset?" then one has to first ask "What is foundation-based architecture?" If you are intrigued by these questions, read on. The word architecture is inherently associated with the portion of a structure that is visible above ground. This is both an omission and a missed opportunity to recognize that the foundation of a structure can contribute as much, if not more, to the realization of a structure. As our planet faces significant growing challenges due to natural hazards such as sea level rise, elevated temperature events, increased precipitation events and more severe wind events, the importance of considering the architecture of a foundation system is likely to become even more critical when the con- sequences of natural hazards such as drought, wildfires, landslides, debris flows, floods, glacial lake outflows and tsunamis, among others, are mani- fested. The above ground physical and societal aspects of infrastructure and the increased demand for below- ground space will require creative problem-solving solutions and con- siderable foresight. Foundation-based architecture will unquestionably play a critical role in helping society adapt to and survive natural hazard stressors that are at best ill-defined and often poorly understood.

Nov 1, 2025

By Adam Hacker

In early 1937, the Ohio River elevated to its highest levels leading to devastating flooding in Louisville, Kentucky. Today, that historical flood, also known as the Great Flood of 1937, is still the flood of record for the area. In an effort to re- duce flooding risk to the population, the Flood Control Act of 1937 was passed to strengthen Louisville's re- silience against future flooding. This triggered the U.S. Army Corps of Engineers (USACE) to construct the Louisville Metro Levee System, which comprises 26.1 mi (42 km) of concrete floodwalls and earthen levees with 16 flood pump stations. One of those flood pump stations was the Paddy's Run Flood Pump Station, which was built in the 1950s, in the western portion of Louisville. That flood pump station was located at an existing stormwater outfall that conveys the stormwater from the western metro- politan area under the levee to the Ohio River. The stormwater flows through the outfall by gravity when the Ohio River is not elevated. When the river is elevated, the flood pump station becomes active after a flood gate at the end of the outfall closes. This is necessary because with- out the flood gate, the Ohio River would backflow into the outfall causing inland flooding. When the flood pump station is active, the stormwater gets pumped over the levee embankment through discharge pipes into the Ohio River. Stormwater can collect in a ponding area and backup during intense rainfall events when the inflow to the flood pump station exceeds the capacity. Recently, Louisville and Jefferson County Metropolitan Sewer District (MSD), which now operates and main- tains the levee system, determined the need to upgrade the existing Paddy's Run Flood Pump Station's capacity to reduce the risk of interior flooding. MSD determined the new flood pump station would need to increase existing capacity from 875 million to 1,900 million gal (4 to 8.6 billion L) a day to account for a 2035 projected storm event, which is a 10-year, 24-hour storm event of 5.0 in (127 mm) in 24 hours. Due to the age and complications associated with up- grading the existing pump station, a new pump station was selected as the preferred approach. In 2021, MSD

Nov 1, 2025

By Frank DiSalvo

As the natural disaster potential escalates and urban coastlines throughout the U.S. continue to bear the brunt of its effects, cities like New York; Jersey City, New Jersey, and Hoboken, New Jersey, are responding with the only effective strategy available: building smarter, stronger and more resilient infrastructure. Nowhere is this more evident than in the vast network of flood protection projects currently transforming the shoreline of the New York-New Jersey metropolitan area. Geotechnical contractor American Pile & Foundation has five major resiliency projects underway, stretching from Hoboken's rail yard to the eastern and western shores of Lower Manhattan. Each of these projects presents unique engineering and construction challenges, particularly given the heavily urbanized, historic and often fragile nature of the terrain. From executing technical foundation work through centuries-old manmade fill to operating adjacent to critical transit infrastructure, these projects demand technical expertise, innovation, con- struction know how and collaboration to help redefine the way the construc- tion industry approaches resiliency. Let's go on a tour throughout the harbor and get a closer look at each site and its unique challenges.

Nov 1, 2025

By Allison Digregorio, Muhammad Ali Naeem, Sam Yao, Joshua Core, Simpson Gumpertz

The Potrero Power Station makes up approximately 1,000 ft (304.8 m) of shoreline on the east side of the San Francisco Peninsula between Pier 70 to the north and 23rd Street to the south. Beginning as early as the 1870s, the site has been home to numerous industrial activities and has not been open to the public in many years. The industrial activities ranged from sugar refining to power generation and gas manufacturing. The Potrero Power Station Project is rehabilitating the waterfront and pro- viding a mixed-use development and public waterfront to reopen the area to the public while also providing robust protection against sea level rise and seismic-induced instability. When transforming such a sizeable post- industrial area, creative design solutions were tailored to each location to increase the grade and stabilize the slope. The solutions implemented ranged from ground improvements to retaining walls.

Nov 1, 2025

By Sarah Banks

"Here and there the grease and filth have caked solid, and the creek looks like a bed of lava; chickens walk about on it...and many times an unwary stranger has started to stroll across, and vanished temporarily." Upton Sinclair offers this revolting - yet accurate - description of the Chicago River in his book The Jungle, originally published in 1906. In the early 1900s, Chicago was a major industrial hub. The Chicago River was not only heavily used for transportation but also for the disposal of waste produced by the meatpacking industry, steel production, rail manufacturing and more. The South Fork of the river was the primary sewer for the Union Stock Yards. The meatpacking industry caused so much pollution, the river became known as Bubbly Creek. Chicago's older buildings were designed to be shut off from the river - no windows, certainly no homes or parks. A river view from an office or hotel was not something to brag about. It wasn't until the 1970s and the passage of the federal Clean Water Act that things began to change. The city now requires public access to the river in all parts and newer architectural designs ensure this is possible. Rather than sewage and industrial waste, the river now carries boat- loads of tourists and kayakers.

Oct 1, 2025

By Marya Gorczyca, Damian Siebert

Air rights projects are inherently challenging as they involve building in the "air space" above an existing structure. From a foundation engineering and installation standpoint there are numerous constraints and additional complexities to consider. This article describes how these issues were overcome for deep foundation design and construction at Lyrik Back Bay - Air Rights Parcel 12, the first successful air rights project over the Massachusetts Turnpike/Interstate I- 90 through this neighborhood in downtown Boston in 40 years. The project is unique in that it is both an infrastructure and commercial development project undertaken as a collaboration between a private development team S&A P-12 Property led by Samuels & Associates, and the state transportation agency, the Massachusetts Department of Transportation (Mass DOT), owner of the land and transportation infrastructure.

Oct 1, 2025

By Lauren Speakman, Mark Reinders, Thomas Fiala

In the heart of downtown Toronto, a full city block at 481 University Avenue and 210 Dundas Street West has become the site of one of the most complex heritage preservation efforts ever attempted in North America. The development of the United Bldg., a 50-storey mixed-use tower, required the complete in-place retention of two culturally designated façades: a 9-storey Beaux-Arts structure built in 1928, and a 10-storey Modern Classical building completed in 1961. The City of Toronto By-law 1393- 2017 designated the façades of both 210 Dundas Street West (Maclean Pub- lishing Company Building, 1928) and 481 University Avenue (Maclean- Hunter Building, 1961) as heritage sites due to their architectural, historical and contextual significance. Regulations imposed by this bylaw prohibited dismantling or relocating any part of the heritage façades. All original finishes brick, stone, concrete and steel - had to remain undisturbed and fully supported throughout construction. At 10 storeys tall, the façade retention system (FRS) designed for this project was a monu- mental engineering and construction marvel that was unprecedented in the industry. The complexity of this project was only amplified by the spatial lim- itations imposed. Dense urban infra- structure - including streetcars, sub- way tunnels and congested utilities not only restricted the available options for the FRS design but also imposed stringent monitoring criteria. The solution selected needed to restrict ground settlement to fewer than 3 mm (0.1 in) and façade movement of 15 mm (0.6 in). This led to the development of a highly integrated hybrid support system, merging elements of the existing structure with the FRS and the support of excavation (SOE) design to allow four levels of underground construction beneath the retained façades and structure. On the United Bldg. project, Canadian specialty contractor Green Infrastructure Partners was responsible for delivering the demolition, shoring scopes and façade retention. This included the full demolition of two brick buildings and the partial demolition of 210 Dundas Street West and 481 University Avenue. The shoring scopes executed the full deep foundation system including secant piles, micropiles, caissons, tiebacks, walers and shotcrete. The façade retention entailed the fabrication, supply and installation of all FRS steel and connections, as well as the jacking of the retained structures onto the new foundations.

Sep 1, 2025

By Andrew Evans

As healthcare facilities evolve to meet the needs of expanding urban popu- lations, the demand for sophisticated excavation support and deep foundation solutions becomes increasingly critical. One such project is the new campus for Children's Medical Center in Dallas - an ambitious expansion set to serve the region for decades to come. At the core of this high-profile project is Oscar Orduno, a Dallas-based specialty contractor. This project, like many at the intersection of healthcare infrastructure and urban development, brings unique geotech- nical challenges. Texas. The expansion includes new clinical buildings, research facilities and a network of support structures - all of which rely on robust and technically sound below-grade construction. The specialty contractor joined the project to deliver an excavation support solution, ensuring that the develop- ment's deep foundations and per- manent basement wall would meet all performance requirements. Given the urban context of the site, as well as being adjacent to ongoing hospital operations, and the substantial depth of excavation, the scope demanded a high level of coordination, technical capability and adaptability. At the center of the site is a perma- nent basement wall, reaching depths of nearly 70 ft (21 m) below street level. The wall's design had to account for immediate earth retention during ex- cavation as well as the long-term structural needs of the new hospital complex. The total project scope con- sists of several new towers, across 33 acres (13 ha) and increasing the total hospital footprint by more than 2 mil- lion sq ft (185,800 sq m). These chal- lenges were met through an integrated system of soldier piles and tieback anchors, engineered and installed to stringent standards.

Sep 1, 2025

By Ed Amos

The morning fog rolled off the Pacific Ocean as engineers surveyed a 27,000 sq ft (2,500 sq m) contaminated slope in Davenport, California. What lay before them represented one of the most challenging environmental remediation projects in recent memory - a steep hillside poisoned by decades of cement production, threatening to leach toxic materials into one of the state's most pristine coastal environments. This case study from a former Cemex cement plant site demonstrates how innovative drilling and soil stabilization techniques can address complex en- vironmental challenges while protecting sensitive ecosystems. The project's success offers valuable insights for engi- neers, contractors and environmental professionals facing similar contam- inated site challenges.

Sep 1, 2025

By Shawna Munn, Katie Castelo, Dave Wiley

Risk is inherent to work in the field of subsurface engineering, and many contract approaches have become so focused on shedding risk that they leave no room for one of the best tools in our industry, the observational method. Its development in subsurface engineering owes its foundation to Karl Terzaghi and Ralph Peck through their respective works dating back as early as Soil Mech- anics in Engineering Practice published in 1948 and "Advantages and Limitations of the Observational Method in Applied Soil Mechanics" in 1969. Throughout their fundamental works, a strong argu- ment for the observational method is made: "... the potential for savings of time and money without sacrifice of safety is so great that every engineer who deals with applied soil mechanics needs to be informed." (Peck 1969) Not every project will benefit from its use, but in today's risk management focused world, projects and contracts should be set up to allow for its use, while sharing the risk clearly and equitably between all parties. Without a proper contractual mechanism to leverage its use, perceived manage- ment of "risky unknowns" will over- ride substantive application of the method, and significant benefits may be lost as a result. As Terzaghi said, "A vast amount of labor goes into securing only roughly approx-imate values for the physical constants that appear in equations Therefore, the results of computations are not more than working hypotheses, subject to confirmation or modification during construction." It is our collective view that sub- surface engineers should take this task of confirmation and modification seriously. We should use the observa- tional method to derive performance- based designs that deliver design economy, constructability, cost and schedule advantages without sacrificing safety or quality. Collaborative style contracts provide a framework to approach shared risk and opportunity with appropriate incentives for the individual parties.

Aug 1, 2025

By Yasir Husain, Deepankar Choudhury, Hamzah M. B. Al-Hashemi, Marwan Alzaylaie

An existing warehouse spanning 12,000 sq m (130,000 sq ft), located in Jazan City on the southwestern coast of the Red Sea in Saudi Arabia, was supported by a reinforced concrete slab- on-grade, while its steel columns stood on bored piles and pile caps. Completed approximately a decade ago, the structure developed severe cracking and floor deformation reaching up to 170 mm (7 in), as per recent site surveys. The deformation evolved without any progressive instrumentation or moni- toring in place, and thus, neither the onset nor the time- dependent behaviour of the issue could be precisely estab- lished. The warehouse remained operational throughout this period, and the owners, faced with ongoing challenges, decided to announce a public bid inviting contractors and con- sultants to propose a feasible rehabilitation solution, given the unique nature of the site and the ongoing operations. To begin with, the city of Jazan is not an easy geotechnical ground to conquer. The region is defined by complex and problematic ground conditions: collapsible loess soil, Sabkha deposits (salt flats), salt domes (which are highly deformable over time), organic expansive clays, flood-prone zones, extreme temperatures, aggressive environmental effects and moderate seismic activity. Salt domes are large underground formations of salt that have pushed upward through overlying layers of rock due to their lower density. Over time, they can deform and shift, causing ground instability at the surface. These structures are particularly problematic for foundations, as the salt can dissolve with water infiltration or move plastically under stress, leading to uneven settlement or sudden subsidence of built structures. Furthermore, the structure in question had to remain in service, limiting the options for rehabilitation due to spatial, operational and construction-related constraints.

Aug 1, 2025

By David Graham

Dedicated by President Franklin Roosevelt in 1940, Chickamauga Lock and Dam is located just upstream of Chattanooga, Tennessee, at Tennessee River Mile 471. The Tennessee Valley Authority (TVA) owns the structure, and the U.S. Army Corps of Engineers (USACE), Nashville District, operates and maintains the navigation lock. Constructed under the direction of the TVA as part of the New Deal, Chicka- mauga Lock and Dam serves the TVA's mandates of flood control, improved navigation and hydroelectric power generation along the Tennessee River and its tributaries. Chickamauga is one of the busiest navigation locks in the country, handling nearly 10 million tons of freight each year. As a critical link in the transportation of goods, particularly bulk commodities like coal, grain and chemicals, its efficiency directly im- pacts the economy. The Chickamauga Lock was designed by the USACE and was based on the design of Guntersville Dam downstream. The Chickamauga Lock is 60 ft (18 m) wide by 360 ft (110m) long. However, the dam was designed to allow a larger 110 by 600 ft (34 by 183 m) lock to be added if needed in the future. That future is now, and the USACE is leading a project to construct a new, larger lock to increase the flow of river freight and address structural issues. Extensive concrete surface cracking was observed soon after the lock and dam was completed in 1940. The cracking is a result of alkali-silica reaction (ASR) and alkali-carbonate reaction (ACR), which cause the concrete to expand. The existing lock suffers from structural deficiencies resulting from ASC and ACR concrete expansion, making a new lock that much more critical. The overall cost of the lock replace- ment project is estimated at $954 million with operational completion estimated in 2028 and final completion estimated in 2031. As part of the project, C.J. Mahan Construction Company was awarded a $61 million contract to con- struct the upstream approach walls that will guide vessels into the new lock. The approach walls were planned to be sup- ported on 28 drilled shafts of 6.5 ft (2 m) diameter. The contract also included a nonproduction technique shaft with a bidirectional load test. The baseline design included four piers, each sup- ported on four drilled shafts, and two nose piers, each supported on six drilled shafts. The drilled shafts included 6 ft (1.8 m) diameter rock sockets ranging in length from 25-45 ft (8-14 m).

May 1, 2025

By Robert Tonning

Boston's Landmark Center, a historic site in the Fenway neighborhood, is undergoing a major transformation. Originally built in 1928 by Sears, Roebuck & Company, the building is being repurposed into a mixed-use development that will breathe new life into the structure while preserving its historical significance. A key aspect of Historic photo of Bo this project is the deep foundation system, which employs drilled micropiles. While these have been commonly used on construction projects for the past several decades, these truly "super piles" pushed con- ventional limits of both drill depths and working capacity in order to meet the project's requirements. The installation of these micropiles presented several challenges, from extreme depths and high capacities to tight timelines and complex site conditions. This article explores the engineering feats, challenges faced and innovative solutions that were developed and implemented throughout the process. Thanks to creative problem-solving and collaboration with the wider pro- ject team, Phoenix completed its work as a geostructural subcontractor ahead of schedule. The Landmark Center has a rich history in Boston's Fenway neighborhood. Before the present building was constructed almost 100 years ago by Sears, the site had been home to a number of factories, warehouses and other industrial buildings dating back to the late 1800s. The location was also near the former Fenway Railroad Yard, a modest transportation hub that served the surrounding area at the turn of the 20th century.

May 1, 2025

By Matthew Conte

Overgrown vegetation. Little to no effective drainage. Three or four different construction methods over the years. Live loads from above. Property line to navigate. Buildings on either side. I drove by this site for years wondering when someone was going to have to deal with it. That day came, and it turned out to be us. This particular project had typical attributes: limited space and restrictive conditions. This retaining wall system supported the neighbor's parking lot above, roughly 14 ft (4 m) in elevation change. At a length of 92 ft (28 m), both ends of the wall abut an active building in the lower property. Only a small parking area of roughly 50 ft (15 m) in depth lies before the heavily traveled state route in Westport, Connecticut. Roughly two-thirds of the existing wall was tiered, and the other third was taller, with a concrete masonry unit (CMU) wall that appeared to be part of a former structure. The existing wall was failing and leaning over the parking spaces. The drainage system showed signs of failure, and the vegetation was clearly retaining moisture and frost was heaving the walls a little more each year. During the initial kick-off of the project, it was decided we would immediately shore up this taller portion of the existing wall. That shoring would stay in place through construction. With active tenants and neighbors, the property owner needed a solution that would allow businesses to stay open and limit any disturbance to the above property. Very little documentation existed showing the construction of the walls or the soil conditions. Above, the neighboring property had added a small retaining wall when its parking lot was constructed. Soil borings were found, but nothing showing details on that newer retaining wall. The borings indicated structural fill was compacted in lifts beneath the lot, but nothing indicating any geotechnical measures beneath the wall, at the property line. We were forced to design a new wall considering the 'worst case' conditions. This new wall also required construction methods that would allow all aspects of the surrounding area to remain intact.

May 1, 2025

By Keshab Sharma, Jibendra Misra

Caissons and piles are mostly used as foundation types in bridges. Caissons are particularly suitable for bridges with expansive spans, locations with deep alluvial deposits, soil prone to lique- faction and when there's a notable risk of vessel collisions. However, they face challenges related to sinking and limited resistance against earthquakes. On the other hand, pile foundations are not well suited for deep-water scenarios due to their excessive length, diminished rigidity, susceptibility to vessel col- lisions and complications associated with construction. A potential solution to the issues mentioned above could be the adoption of CCPF. These foundations can also be applied to enhance existing caisson. foundations through retrofitting techniques in wind turbines, trans- mission lines and bridge foundations, demonstrating their adaptability and potential for improving the perfor- mance of foundation systems. There has been successful implementation in China, as evidenced by projects like the Qiongzhou Straits Bridge and the Longna Highway Yangtze River Bridge. Moreover, this foundation approach has been adopted for numerous cross- sea bridges globally, including ex- amples like the Benicia Martinez Bridge (U.S.) and the Hitsuichi-Jima Bridge (Japan). Research from 2016 has shown CCPF systems can be potentially used for offshore wind turbine foundations and retrofitting existing caisson foundations. The construction sequences of CCPF systems involve the sinking of caissons followed by driving the pile beneath the caisson. There are two possible options for connecting the pile with the caisson. The first option can be provided by ending the pile at the bottom plug level of the caisson, in which the pile is threaded into the caisson bottom to achieve a connection joint between the caisson base and the pile tops. This methodology enhances the flexibility of the foundation. The second method is to continue the pile up to the cap level of the caisson. The pile up to the cap level of the caisson provides better integrity than the first option between caisson

May 1, 2025

By Jason Reinhardt, Devon Switser, Nick Strater, Bob Stier, Joseph Reed

Originally constructed from 1828-1850, the Chesapeake & Ohio (C&O) Canal was one of the first largescale civil works projects funded by the U.S. Government, with supplemental funds from Mary- land and Virginia. The canal's navi- gational system stretched along the Potomac River for 184.5 mi (296 km) from Washington, D.C., to Cumberland, Maryland. The C&O Canal's navigational system was primarily comprised of locally sourced materials such as stone, earth, timber, mortar and brick. The Paw Paw Tunnel was con- structed by the C&O Canal Company in lieu of building 6.7 mi (11 km) of canal along the Potomac River (referred to as the Paw Paw Bends). The tunnel is approximately 3,118 ft (950 m) long, 25 ft (8m) wide, lined with six million bricks, and included open cuts through the interbedded shale and siltstone on both sides of the approaches to the tunnel en- trances. The excavation passed through the Tunnel Hill Ridge and the Valley of Mill Run (a stream that still conveys water through the cut in the form of waterfalls). After the full section of canal through the project area was opened in 1850, it remained in commercial oper- ation for 74 years until 1924. Today, the Paw Paw Slope Stabiliza- tion Project is located in one of the most remote portions of the Chesapeake & Ohio Canal National Historical Park, approximately 155 river miles (250 km) upstream of Washington, D.C., and under the management of the National Park Service. There is a rich history of rock fall and slope instability within the cut on the downstream approach to the tunnel. This is due to a combination of

Apr 1, 2025

By Jose Caicedo, Elmar Buhl

Polyurethane based ground injections are most frequently used to stabilize shallow foundations that have under- gone settlement due to soil shrinkage, softening of the ground by water (e.g., heavy rainfall or defective sewer pipes), or planning errors regarding the bearing capacity. The expansive reaction of the injected polyurethane, together with the counter-pressure of the foundation, results in a ground improvement of the soil layers underneath the foundation. When more material is injected, a releveling of settled shallow foundations or concrete slabs is possible. Due to more frequent reuse of existing buildings in urban areas, we have seen an increase in requests regarding the reuse of the existing foundations under increased loads. Sometimes the load increase can be accommodated by the existing foun- dations without any modifications, but it is often the case that the new load exceeds the bearing capacity of the old foundation. In this case, there are several options to strengthen the foundation. Most commonly, sectional underpinning and retrofitting micro- piles along the foundation are used to increase the bearing capacity. An alternative option is the strengthening of the ground under the existing foundations to increase the bearing capacity and to minimize settlement due to the new load. In the last few years Uretek, a provider of polyurethane based ground injections, has frequently applied these injections to successfully perform the necessary ground improvement in the context of building reuse or the addition of new stories to buildings. This article will present a case study of a residential building in Hamburg, Germany, where an additional story was planned and the bearing capacity of the existing shallow foundations was not sufficient for the new load. In this case expanding geopolymer injections were used to gain the necessary bearing capacity and the effect was monitored by an in-situ load test. A second case study will briefly illustrate an experimental project where ground injections were used to increase the skin friction of a micropile foundation at a parking garage in Munich before the addition of three new stories.

Mar 1, 2025

By Morgan Eddy, Andy Steele

With its rich history and rapid urban development, the Mount Vernon Triangle neighborhood in Washington, D.C., is ready to welcome a new addition: Claret, a 12-story, 127- condo residence. Tasked to maximize below-grade space for the new development, Steelle Foundation converted an existing parking lot by excavating up to approximately 30 ft (9 m) deep. The team navigated many challenges, including proximity to an adjacent building, limited access to the site and a mandate to preserve a century-old Heritage Tree. a specialized foundation engineering approach. The catalyst for the project was the growing demand for high-quality residential spaces in the area, combined with the site's strategic location.

Mar 1, 2025

By John Morris, Scott Stonecheck

The University of Pittsburgh wanted a new arena constructed for its collegiate wrestling, volleyball, and gymnastics, dance and cheer programs. Due to space constraints for the arena in the university's congested urban setting, the school selected a location atop a previously demolished football stadi- um originally constructed in 1925. The new Victory Heights Arena and Sports Performance Center is nestled between the Peterson Events Center, student residence buildings Panther and Irvis Halls, and other critical campus infrastructure. Due to the site's con- straints, a permanent tied back soldier beam wall system was programmed for the subterranean portion of the arena's perimeter foundation wall, with the soldier beams and tiebacks using a delegated design-build approach and the permanent wall facing being designed by the building's structural engineer of record. Design and construction of the soldier beam wall system required a mix of conventional and unique approaches to address topographical, geological and site challenges. This article will provide an over- view of the approaches to the various challenges, the design concept, effi- ciencies gained through the design assist strategies employed through the early phase of the project, and lessons learned from site and geological dis- coveries uncovered and safely over- come during the physical work.

Mar 1, 2025

By Abdul Amir Alhelu

The Cardinal Hill slope movement repair was an urgent project, and a high priority, time-sensitive project for the Louisville Water Company. Cardinal Hill is a critical water distribution facility that serves a majority of Jefferson and Bullitt Counties, and parts of Hardin and Nelson County, Kentucky. On March 14, 2019, the Louisville Water Company issued a certificate of emergency based on evidence of impending slope failure, which could cause a catastrophic break in a 60 in (1.5 m) diameter transmission line and loss of a 30 million gal (114 million L) reservoir. The reservoir would fail due to the pipe failure. The subsurface conditions generally consisted of a stiff silty clay extending to about 27 ft (8 m) below the shoulder of the road, where a weathered siltstone was encountered. The siltstone was about 3 ft (1 m) thick and underlain by shale. The earth auger sampling tools encountered refusal material (shale) at about 30 ft (9 m) deep. The boring was extended about 5 ft (1.5 m) into competent shale using a roller bit. Two borings were drilled on the slope on the south side of the fence in the neighbor's yard, encountering refusal material at 11 ft (3 m) near the driveway and at 4.5 ft (1.3 m) on the upper plateau.

Jan 1, 2025