Search Documents

By Peter Sudkamp, Ariel Sarno, Andrew J. King

The design and installation of elliptical shafts for the City of Baltimore, Maryland DPW Contract SC-940, “Hydraulic Improvements to the High-Level Sewer Shed Collection System” (SC-940) will be discussed as a case study for elliptical shafts as an alternative to standard circular, rectangular, or square shafts. The project involved construction of 21 shafts varying from 6 meters (m) to 12 m (20 feet (ft) to 40 ft) in depth. Eighteen (18) of 21 shafts were constructed utilizing liner plate and ring beams including 15 elliptical shafts. Construction challenges included site condition difficulties, namely grouting of boulder cavities, keeping the correct orientation of the slender shaft elements, and minimizing impacts to the construction schedule from the added time necessary to stagger the liner plates, ring beams, and blocking. However, utilizing an elliptical shaft design allowed for property features to remain accessible, management of conflicting utilities within the excavation footprint, and reduced shoring and disposal cost. Ultimately, the decision to utilize elliptical shafts provided a cost saving over traditional shoring options.

Oct 31, 2023

By Mark Wade

This presents an overview of the successful construction of a large diameter using trenchless technologies for renewal in Casper, a region with few large-scale projects. This project preserved and enhanced the City's aging wastewater infrastructure for an additional 100+ years. The pipeline, known as the North Platte Sanitary Sewer Interceptor (NPSSI) represents a nine-mile conveyance system that was initially constructed in four phases between 1980 and 1983 as part of a wastewater regionalization effort in the Casper metropolitan service area. The pipe material for the interceptor was unlined reinforced concrete pipe (RCP). Due to elevated levels of H2S within the pipeline, associated sulfuric acid formation became problematic along the entire interceptor alignment, causing serious deterioration of the NPSSI. The project team of CEPI, BlueWater, and Jacobs utilized a series of internal inspections and investigations of the entire interceptor over a three-year period to assess its condition and requirements for rehabilitation. This led to the first phase of strategic rehabilitation utilizing cured-in-place pipeline (CIPP) by Aegion/Insituform. Construction of the most critical portions of the NPSSI began in mid-2022 and was completed in early 2023. The project scope consisted of 7,600’ of 48-54” pipe rehabilitation along with numerous deep-bury point repairs, junction structures, river siphons, and inlet/outlet structures. Despite record cold winter weather and numerous site challenges encountered, Insituform Technologies delivered the project to the City of Casper with only a single time extension. The total cost of the project was below the original contracted amount, or $8.1M. The Casper NPSSI demonstrates who the successful renewal of a deteriorating wastewater interceptor within a stream-sensitive aquafer can be done using trenchless renewal in the best way possible. Added value was provided from the collaboration by all stakeholders, careful planning, and executing innovative technologies, to achieve an outcome beyond expectation.

Oct 7, 2024

By Tajebe Bezabih, Tonya Sanders Thach, David Sinkhonde, Samia Kirchner, Hunter James, Derrick Mirindi

With the increasing demand for wood driven by population growth and urbanization, this study explores the potential of three-layer particleboards reinforced with waste fibers as a sustainable and eco-friendly alternative in building material technology. It focuses on various waste fibers such as sisal, bagasse, leather shavings, and waste papers, assessing their impact on the structural properties of particleboards. The research thoroughly evaluates key mechanical properties such as the modulus of rupture (MOR) and modulus of elasticity (MOE), as well as essential physical properties like water absorption (WA) and thickness swelling (TS). This investigation delves into the innovative use of organic and natural bio-waste particulates as reinforcing agents in polymer composites, specifically examining their role in enhancing particleboard characteristics. A significant finding of this study is that the enhanced particleboards not only meet, but sometimes exceed, the minimum standards set by various international guidelines for general purposes. This indicates that it is feasible to replace traditional wood fibers with certain organic waste materials while maintaining or even improving the performance of conventional particleboards. This advancement is particularly relevant to the construction industry, as it suggests that these improved particleboards can be effectively used as sustainable structural materials. By utilizing waste fibers, it not only aligns with global sustainability goals but also provides a practical solution for waste management across multiple industries. Consequently, this research represents a significant step forward in the development of building materials that support eco-friendly construction practices and contribute to the circular economy.

Oct 7, 2024

By Paul Creswell, Hannah Davies

London City Airport’s only runway perches on a narrow finger of land close to the old city of London. Formally the central quay of the Royal Docks, the runway is encircled by redundant deep-water berths that were heavily bombed during World War II before its conversion to an airport in the late 1980’s. The owners’ need to increase capacity drove the addition of a parallel taxiway to the runway formed of a 20acre reinforced concrete deck supported by piles over the dock. This paper presents a number of the challenges experienced during the installation of over 1000 piles into the existing dock using cased rotary bored techniques under polymer support fluid for the expansion of the airport. The complex nature of London geology, including features which have not been seen in this detail before, across a site that extended over 1000m in length, required significant time and resources to determine the contributing factors to a number of piles collapses. The most significant causes were locally instability in the Thanet Sand Formation due to faulting and loss of dilatancy associated with post deposition shearing as well as a disturbed ground and groundwater regime due to puncturing of the puddle clay dock liner during UXO clearances. This paper will discuss these challenges encountered and how they were overcome.

Oct 31, 2023

By Joe Smith, Roberto Rodriguez, Francisco Ciruela-Ochoa

Drilled-In Displacement Piles (DDPs) present some advantages over other deep foundation solutions making them suitable for challenging conditions encountered at John F. Kennedy (JFK) International Airport Headhouse Expansion Project. For one, elevated railway tracks required the installation to occur with as little as 12 ft of clearance. Secondly, their ease of installation and overall material requirements deemed them more efficient than traditional micropiles from a schedule and cost point of view. Lastly, the low vibrations induced by DDPs to the surrounding sensitive structures were crucial for an operational airport. All combined contributed to the final decision of recommending this foundation system for the Project. This paper documents the use of DDPs for the Project and documents the design and specification process along with load testing program results and observations made during the construction of production elements from a case history perspective.

Oct 31, 2023

By Francisco Humire

Contemporary design criteria for ground improvement supporting structures frequently specify a maximum post-liquefaction reconsolidation settlement value. Typically, those settlement values are evaluated using methods developed to represent free field conditions in the absence of ground improvement. Centrifuge and full-scale field tests have shown that arrays of dense gravel columns reinforce the ground leading to a reduction of post-liquefaction settlements relative to free field values. Therefore, free field settlement estimations that do not account for the vertical reinforcement effects provided by columnar ground improvements lead to conservative estimates of post-liquefaction settlements. Gingery (2019) proposed a constitutive model able to capture the development of post-liquefaction volumetric deformations and presented its implementation in a finite difference numerical model. The model proposed by Gingery (2019) has the advantage over more simplified approaches in that it more rigorously captures many of the physical processes including porewater pressure dissipation, gradual regain of soil stiffness and strength, downdrag, and stress redistribution. The objective of this work is to further validate the constitutive model proposed by Gingery (2019) and investigate the post-liquefaction settlement reduction due to vertical reinforcement effects for different subsurface profiles. This is done by (1) validating the constitutive model against more recent centrifuge and full-scale field tests, and (2) quantifying the post-liquefaction settlement reduction that is attributable to vertical reinforcement effects for different site conditions. Our simulations show a reduction of 15 to 20% of post-liquefaction settlements relative to free field values when considering vertical reinforcement effects.

Oct 7, 2024

By Joseph Seibold, Kavin Khatri, Siobhan O'Reilly-Shah, Neel Neelakantan

San Francisco’s New Headworks Facility Project consists of the design and construction of a state-of-the-art Headworks Facility designed to treat up to 250 million gallons of wastewater a day. The site is located in the Bayview District of San Francisco, California and is subject to various geohazards, including liquefiable artificial fill, compressible Bay Mud, multiple aquifers (including a pressurized aquifer), and high seismicity. To mitigate these hazards, and to accommodate the anticipated structural load demands, the New Headworks Facility structures were designed to be supported on large diameter drilled shafts. Bi-directional load tests (BDLTs) were designed and carried out to calibrate the analysis and confirm the design. During pre-production construction, two 36-inch-diameter drilled shafts approximately 125 feet long were installed at the project site. Each drilled shaft was instrumented with a bi-directional load cell, Linear Vibrating Wire Displacement Transducers, and eight strain gauges at select locations. The BDLTs were carried out after shaft installation. With careful consideration of the geotechnical conditions, the upward and downward displacement of the shaft segments above and below the bi-directional load cell mobilized at about the same time, allowing for significant data acquisition that resulted optimization for the foundation design. Through the successful implementation of a BDLT program, the drilled shaft lengths were able to be reduced significantly, resulting in substantial cost savings to the San Francisco Public Utilities Commission (SFPUC). This paper presents a discussion of the BLDT program performed for the New Headworks Facility Project, and how BDLT can be implemented as an effective method for estimating capacities on large-scale public infrastructure projects. Keywords: Bi-directional load testing, load cell, drilled shafts

Oct 7, 2024

By Takefumi Takuma, Masashi Nagano, Yuichi Matsuoka

Pressed-in sheet pile bulkheads were built as part of an environmental cleanup known as the Gowanus Canal Environmental Remediation Project in Brooklyn, New York. These pressed-in piles minimized the potential settlement and displacement along the existing canal frontage and nearby buildings. The sheet piles were fully interlocked to be impervious, which was verified with non-declutching sensors. The soil conditions consisted of a top layer of contaminated soft sediment with debris and underlying sand and gravel layers with equivalent N-values ranging from 20 to 100. Coated Z-shaped sheet piles in lengths of up to 70 feet were installed.

Oct 31, 2023

By Scott Lakes

In recent years, Southeast Florida water agencies have been collaborating to develop a regional water supply that is sustainable and affordable. The C-51 drainage canal was selected as a leading candidate for the construction of a water reservoir – named the C-51 Reservoir – to store raw water for future use. The reservoir will capture storm water that is currently lost to the Lake Worth Lagoon estuary for storage. Phase One, recently completed, is estimated to store 14,000 acre-feet and supply 35 million gallons per day (MGD) of raw water to participating utilities. In addition to sustainable water storage and supply, the C-51 Reservoir Project will reduce excess freshwater discharges to the brackish Lake Worth Lagoon and improve water quality. The reservoir would also serve to assist with flood control and Everglades restoration efforts The reservoir design includes a cutoff wall that runs the entire length of the embankment’s axis. The cutoff wall largely consists of a minimum 2.5-foot-wide soil-bentonite (SB) wall with a small section of a soil-cement-bentonite (SCB) wall where twin 96-inch diameter conveyance pipes for the gated control structure cross the cutoff wall alignment. The total length of the cutoff wall is about 20,400 feet and extends through a limestone stratum into underlying sands with a total depth of about 50 feet. The cutoff wall ties into an RCC embankment. This paper provides the approach to construction, quality, and lessons learned from the cutoff wall construction. Details and issues with the cutoff wall tie in are described. Keywords: cutoff wall, soil-bentonite

Oct 7, 2024

By Alan Walka, Paul Deterling

Nestled among the lovely 19th century Greek revival, Queen Anne and Italianate architecture, Somerville High School sits atop the Spring Hill in Somerville, Massachusetts. Originally constructed in 1872, the high school has experienced several major renovations and This is the first in a additions throughout it 147-year history. Citing inefficient heating and cooling systems, inadequate access, structural repairs to its exterior, and that all major building systems were at the end of their useful life, the Massa­chusetts School Building Authority approved a feas­ibility study for construction and renovation and city residents voted overwhelmingly to fund the estimated $256 million project, making it the most expensive high school construction project in Massa­chusetts' history.

Jul 1, 2024