Search Documents

By Paul Thurlow, Richard K. Lipscombe

The measurement of deflection of designed diaphragm walls is critical for near real time information to assess wall and soil behaviour as the internal area is excavated in a controlled manner. Data enables the site team and designers to check performance of the design, which is linked to safeguarding the site and the external stakeholders.This paper documents the use of Shape Accel Arrays at the Tottenham Court Road Western Ticket Hall during excavation and propping within the diaphragm wall for the Crossrail project. It shows how the data obtained was used within the site settlement management plan to assist in the control of the works and the information used for Value Engineering purposes that benefitted the project.The use of Shape Accel Arrays for measuring the deflection of retaining walls is not commonplace in the UK construction industry, with the Tottenham Court Road Western Ticket Hall being one of the first times they have been used in such a way. A detailed analysis of the data obtained from the instruments has been undertaken, and compared to the results obtained from the manual inclinometers that were read next to the SAAs. The advantages of the relatively new SAAs have been discussed, as well as other applications of the instrument.

Jan 1, 2017

By Gang Guo, Zhong Liu

"In response to an increasing demand of anchored structures for underground space and transportation infrastructure in China, an innovative underreamed ground anchorage system was created. The novel anchorage system has provided more efficient functions with higher capacity at lower cost, because of the enlarged cylindrical body (known as ECB) sealed in capsule at bottom of anchorage. This paper presents the detailed structure of innovative anchorage system and its special features. To investigate the bearing mechanism of new anchorage, we evaluate its performance and failure mode based on the experimental results, and also indicate its strain-hardening load-displacement relationship. Unlike the shaft anchorages, it is identified no overall failure to be found in soil surrounding the underreamed anchorage. More importantly, the anchorage capacity is governed by the base resistance, which takes more than 80% of total pullout capacity resulting from the contribution of ECB. Finally a case history of anti-floating project introduces the new combined construction approach and procedure, which has provided the contribution to the quality control and cost efficiency.INTRODUCTION AND BACKGROUNDThe construction boom over two decades in China has resulted in an increasing demand for underground space and slope stability. The infrastructures market requires the more efficient anchorage systems for retaining structures, resisting uplift forces and slope protection. The major concern focuses on gaining higher capacity and lower cost resulted from perfecting anchorage systems. There are three main anchorage systems designed to achieve the above objectives: ? single bore multiple anchorage system (Barley 1997), ? regroutable anchorage system (Smoltczyk 1991), ? underreamed anchorage systems (Xanthakos 1991). Generally, the concept ? comparing with the other two, can be more competitive due to its distinct advantages. To improve the performance and durability of ground anchorages under the complex geological conditions and diversified engineering requirements, a number of different underreamed anchorage technologies had been used, which included cone - shape anchorage described by Liao, Wu and Shu (1997) in Taiwan, Soilex anchorage developed in Sweden (Massarsch et al. 1997), Soletanche anchorage proposed in France, blasting anchorage used in Czechoslovakia (Hobst and Zajic 1986), jet-grouting anchorage innovated in Europe (Anon 1988), as well as deep mixing anchorage created in Japan (Cheng et al. 2000).The underreamed anchorage systems have the remarkable advantages compared to the shaft anchorage system. However, there are also some weaknesses inherent in the underreamed systems. For instance, the mechanical underreamed anchorage is unsuitable in sand or waterbearing ground, because the enlarged hole is easy to collapse, and it is hard to ensure the quality of anchorages. On the other hand, relying on the blasting in deep hole, the geometrical space and dimension of enlarged hole is uncontrollable, meanwhile, the continuous blasting operations may easily cause the serious ground deformation and the negative effects to the completed anchorages."

Jan 1, 1900

By Edward Jacobsen, Patrick J. Lydon

"The ongoing expansion of the Oak Creek Power Plant in Oak Creek, Wisc., includes a tunnel bored in rock that connects to four vertical intake shafts approximately 1.5 miles (2.4 km) offshore in Lake Michigan. In 2004, Case Foundation Company was awarded a lump sum contract to install these intake shafts. In spite of delays that shortened the May to September construction season by up to 50%, four shafts and liner assemblies were drilled in 2005 and 2006. The shafts were connected to the tunnel in 2007 by mining upward to reach the lower portion of each liner and then removing its internal bulkheads so that lake water fl owed into the tunnel. The project is one of the largest private construction projects ever undertaken in Wisconsin. The expansion adds 1,230 megawatts of generation. In addition to the tunnel and offshore work, there will be 16 miles (26 km) of railroad track and 6 million cubic yards (4,600,000 m3) of earth work. The 27 ft (8.2 m) diameter tunnel, drilled some 150 ft (46 m) below the surface of Lake Michigan, originates onshore at a pump house. A structural slurry wall was constructed as the foundation for the pump house. The tunnel passes to the south near the current water intake before bearing east toward the new offshore intake shafts, which are 12 ft (3.6 m) diameter by 108 ft (33 m) long steel liner assemblies. These were grouted in place from approximately 3 ft (1 m) above the crown of the intake tunnel and then to 20 ft (6 m) below the lake bottom.Site GeologyOffshore. The plant site is north of the Racine-Milwaukee county line in an area affected by glacial activity. The soil conditions encountered at each shaft location were consistent, with noticeable variations occurring in the top of rock elevations that sloped downward from the innermost to the outermost shaft."

Jan 1, 2008

By Scott Dodds

"The Oxford Hydroelectric Station was a unique project that incorporated a variety of dam strengthening methods to stabilize the facility in order to meet the standards required by Federal Energy Regulatory Commission (FERC). The dam stability and Probable Maximum Flood (PMF) remediation work consisted of (1) construction of a new emergency spillway; (2) installation of 75 high capacity rock anchors; (3) construction of an anchored concrete powerhouse buttress; (4) construction of cast-in-place and sheetpile flood walls; and (5) design and construction of a permanent soil nail wall. INTRODUCTIONThe Oxford Hydroelectric Station is one of 11 hydroelectric facilities owned and operated by Duke Power along the Catawba/Wateree River. The Catawba River originates in the foothills of the Appalachian Mountains just west of Morganton, North Carolina. The river flows east out of the mountains and, at a point just below the Oxford Dam, the Catawba River turns and heads southeast. The Catawba River continues to flow southeast past Charlotte and into South Carolina where it eventually becomes the Wateree River. The Wateree River eventually flows in to the Atlantic Ocean.Located a few miles east of Hickory, North Carolina, the Oxford Dam and Hydroelectric facility is in the upper reach of the Catawba River. Oxford Dam creates the third impoundment along the river known as Lake Hickory. Lake Hickory is well known locally for providing many outdoor activities such as boating, jet skiing, canoeing and fishing. The dam and powerhouse were put into operation in the spring of 1928.Key features of the dam include a short embankment section on the south end of the structure, a 391-foot (119m) long south bulkhead and powerhouse, 540-foot (165m) long gated spillway section and a 235-foot (71.6m) long north bulkhead. The maximum height of the dam is approximately 100-feet (30m) from the crest to the dam/rock interface. (See Figure 1).The work associated with this project is the result of licensing requirements of the Federal Energy Regulatory Commission (FERC) which mandates that all hydroelectric facilities have the capacity to safely discharge runoff created by a critical rainfall event defined as the probable maximum flood (PMF). Duke Power, a division of Duke Energy (DUKE) submitted an initial PMF report in 1992 which indicated that at the Oxford Dam would be overtopped by approximately 10-feet of water during the modeled PMF event. Given the duration and depth of the overtopping, significant damage to the facility and a possible breach could result. Therefore, modifications to the existing facility were necessary to satisfy the report of the PMF model."

Jan 1, 2005

By Shreya Vivek Hokam, Dr. A. I. Dhatrak, S. W. Thakare, Dr. Vivek S. Hokam

Construction in congested urban areas has necessitated tall and massive structures. In urban areas, it is common to construct underground structure nearby existing buildings. Selection of an appropriate support structure system to be implemented in the excavation in an urban area is heavily dependent upon the geotechnical conditions and safety of the surroundings and neighbouring structures. Urban Rail, popularly referred to as Metro Rail, has seen substantial growth in India in the recent years. More cities are experiencing the need for metro rail to meet their day-today mobility requirements. The metro structures involved deep excavation for foundations which induces the stresses and thereby alters the existing equilibrium and thus may affect stability of neighbouring structures considering safety point of view. Hence, design and execution of deep excavations become one of the important challenging tasks of any geotechnical engineer in the modern era. Further, it is important to control the ground movement in order to prevent the failure of excavations. This involves specialized foundation technologies, usage of sophisticated equipment and new methods in underground construction, safety and monitoring systems. In this paper the methodology used for protecting adjoining structures due to deep excavation for Nagpur Metro station is studied.

Sep 1, 2022

By Brandon Smith, William Bohlen

Riverbank erosion along the Brazos River has modified the structural support conditions for an existing bridge structure in Southeast Texas. The 8-span, 1,200-foot long bridge was completed in 1992 along Highway 99, a key corridor for the Houston area. Foundation support conditions have been altered due to natural, ongoing river morphology for three bents on the affected riverbank. Recent events include three storms within a three-year period that each exceeded the 500-year return probability. This resulted in accelerated erosion along the northern riverbank. Over forty vertical feet of soil has been removed in some locations. Drilled shaft foundations are now functioning as columns. This review considers the behavior of columns and deep foundation elements due to the modified support conditions. The review ultimately presents a rational methodology for the review of the present and anticipated future bridge configuration with respect to current strength, service, and extreme event limits, with corresponding safety factors for the design. Introduction and Background The Fort Bend Grand Parkway Toll Road Authority (Owner) oversees the State Highway 99 Judge Jodie Stavinoha Bridge over the Brazos River. The 8-span, 1,200-foot long bridge was originally designed with four southern approach spans of 115 feet; a three-span continuous river crossing with span lengths of 195 feet-235 feet-195 feet; and a single northern approach span of 115 feet. Figure 1 provides an overview of the northern portion of the bridge. Table 1 provides a summary of the original bridge substructure configuration. When the bridge was completed, the centerline of the Brazos River was located at midpsan of the main span and the northern high bank was originally located at Bent 7. Erosion process has forced the northern high bank to Abutment 9 (also called Bent 9), and the river centerline during normal flow conditions is located south of Bent 8. The overall estimated river excursion at present day is approximately 270 feet to the north from its original location. An erosion wall that was installed in 2017 limits further erosion of the north river bank within the 300-foot width of the roadway corridor right-of-way. This study was developed to better understand the existing conditions, and to forecast the need, nature, and criteria for potential future improvements.

Jan 1, 2019

By Seth H. Hamblin, Leo J. Hart, John E. Regan

The Route 6 /10 10 Interchange Design/Build project, located in Providence, Rhode Island, involves the design and construction of five (5) new elevated bridge structures to replace and reconfigure the existing interchange and to provide a link between Route 10 northbound and Route 6 westbound. Due to site logistics, headroom restrictions, and depth to bedrock, 50 ton drilled micropiles installed in the deep medium dense sand strata were initially proposed as the deep foundation solution. Post project award, Geosciences Testing and Research, Inc. (GTR) performed various analyses and developed an alternate driven pile solution using steel Tapertube. The results of these analyses indicated that driven steel taper tube and steel pipe piles could develop greater capacities than the drilled micropiles in the granular soil layer, thereby reducing the number of foundation elements, decreasing construction schedule and providing a more cost effective foundation alternative. A comprehensive driven pile load test program was subsequently executed by GTR and the Design Build Team led by Barletta Heavy Division of Canton, Massachusetts, to assess the performance of Tapertube and steel pipe piles, including pile drivability, load-deformation characteristics under static and dynamic loading, and to develop site-specific design parameters in two (2) distinct test areas. The test pile program included dynamic, static compression, tension and lateral load tests on each test pile. Load test measurements were automated with embedded Vibrating Wire Strain Gages (VWSG) to measure load transfer with depth. The execution and results of the successful pile load test program are presented and offer unique case study and valuable data for the use of Tapertube piles on deep foundation projects in the New England region INTRODUCTION The Rhode Island Department of Transportation (RIDOT) Route 6 / Route 10 Interchange is located west of downtown Providence. Originally constructed in the 1950’s as a highway bypass around the historic Olneyville neighborhood, the interchange consists of a series of nine (9) bridges and ramps that serve as a vital east-west link between Interstate 295, 95 and 195. Based on recent bridge rating assessments, seven of the nine bridge structures are rated “structurally deficient”. With many bridge structures shored with temporary supports as many as 15 years ago, the interchange is in critical need of replacement. In 2018, RIDOT awarded the Route 6/10 Reconstruction Design-Build Project to 6/10 Constructors, Joint Venture. Led by Barletta Heavy Division of Canton, Massachusetts, the Design Build team includes O&G Industries, DW White Construction, Aetna Bridge Co. and AECOM. The scope of work includes the replacement of the bridges and ramps, and will provide direct access from Route 10 northbound to Route 6 westbound. Valued at over $400M (US), this is currently the largest project awarded in RIDOT history.

Jan 1, 2019

By Kevin Green, Iván Contreras, Aaron Grosser, Jon Ausdemore, Rachel Leier, Amr Ragy

"Construction of a new tailings dam was required to increase tailings storage capacity at a trona mine near Green River, Wyoming. The new dam was founded on overburden soils underlain by both fractured and competent bedrock. The stored tailings and water had high salt content, resulting in salty seepage water. To reduce the impact of the salty water on groundwater and the Green River, the design of the new tailings dam included a 257,260 SF (23,900 m2) seepage cutoff extending into competent rock.An extensive subsurface characterization was performed prior to completing the design and suitable seepage cutoff methods were evaluated. The approach selected was a full replacement panel using hydromill and clamshell for construction and self-hardening slurry (SHS) for the wall material. Laboratory testing was performed and ongoing monitoring has continued to evaluate the hydraulic conductivity and seepage cutoff performance in the briny environment.The paper includes project background, the collaborative approach and outcomes of the QA/QC program, and the monitoring results for the seepage cutoff wall.PROJECT BACKGROUNDCiner Wyoming, LLC (formerly OCI Wyoming, LLC) owns and operates the Big Island Mine facility near Green River, Wyoming. This underground trona mine has produced soda ash since 1962. The Greater Green River Basin covers much of southwestern Wyoming and extends into northeastern Utah and northwestern Colorado. The Ciner facility is located in the Green River Basin, which is part of the Wyoming Basin physiographic province. The Green River runs to the west and the south of the Ciner facility.Beginning in the early 1990s, Ciner primarily disposed tailings underground in mined-out panels. However, in recent years, underground storage has become limited and some disposal has transitioned to the ground surface. Long-term planning revealed a need to expand Ciner’s surface tailings disposal capabilities. Pond 2, a previously permitted disposal area, was identified as the most viable location for a storage facility. The Pond 2 site is directly north of the Ciner plant facilities, northwest of the active Upper Delta tailings storage facility, and northeast of the Green River (Fig 1)."

Jan 1, 2016

By Renzo D. Verastegui, T. C. Michael Law, Sitotaw Y. Fantaye, Alfredas Daugiala

"When completed, 520 Park Avenue will amend the Manhattan skyline and be one of the most prestigious high rise towers in New York City. The 52-story condominium building is located on a 60 by 100 feet lot on East 60th Street between Park and Madison Avenues. The geographically complex site is bounded by two fragile 5-story masonry buildings on the east and west, a mid-rise building on the north, and a New York City subway tunnel on the south. To add to this complexity, the ambitious development required 70 to 80 feet of excavation, mostly below groundwater level in highly permeable rock, to accommodate four levels of cellars. The new building also cantilevers 24 feet over a five-story historic building on the east. The limited footprint of the building coupled with large compressive and tensile axial loads, considerable base shear and over-turning moments, and the required deep excavation, presented unique foundation challenges. This paper describes how the challenges were solved with an innovative combination of permanent secant pile walls and drilled shafts.INTRODUCTIONThe project site is located at 45 East 60th Street, on the block bounded by East 61st Street to the north, East 60th Street to the south, Park Avenue to the east, and Madison Avenue to the west. As shown in Fig. 1, the site is surrounded on three sides by buildings sensitive to differential settlement. In addition, a NYCT underground subway structure lies below East 60th Street approximately 13 feet south of the site. The base of the subway structure is approximately 42 feet below the street.The project consisted of constructing a 52-story tall building. A portion of the superstructure cantilevers 24 feet over an adjacent five-story historic building. The underground construction for the new building involved a four-level basement, extending about 60 feet below ground surface. The excavation subgrade is much deeper than both the subway structure and the adjacent shallowly-founded building foundations."

Jan 1, 2016

By Xavier Pita, Alexandre Pinto, António Cristovão, Rui Tomásio

"The cutter soil mixing technology was been applied in Portugal since the last seven years. The aim of this paper is to present the main design and execution criteria, related with both the cofferdam and foundations solutions, using soil-cement panels, reinforced with steel profiles, at the new Leixões Cruise Terminal, located at the Leixões Port, in Portugal. The Terminal building was built with one basement on a marine environment, over very difficult geological and geotechnical conditions, which demanded the use of some unusual and integrated geotechnical solutions. It is also pointed out the importance of the QC/QA, as well as the technical, economic and environmental advantages of the cutter soil mixing technique, comparing with same more conventional solutions.1 INTRODUCTIONThe construction of the new Cruise Terminal at Leixões, main gate of the Atlantic Ocean to the North of Portugal and Spain, as a consequence to the constant increase of the cruise traffic, was a challenge from both the geotechnical and structural point of views, mainly due to very difficult and unusual conditions, ranging from the geological and geotechnical scenario to the existent and under operation Leixões Port infrastructures, mainly the South break water, as well as the existent cruising boarding deck (Figure 1).According to the Terminal Project it was necessary to build one basement below the water table level, including several earth retaining structures in order to allow the excavation works on dry conditions leading to a global cofferdam effect. For this purpose soil - cement panels, using CSM technology, reinforced with steel profiles, micropiles (both for foundation and cut off effect) and the existent sheet piles were used. Also pointed out are the adopted special foundations of a very complex structure, including bored piles and micropiles (Figure 1)."

Jan 1, 2015

By David R. Sutfin, Joseph Lodde

110 N. Carpenter is new commercial building located in the West Loop neighborhood of Chicago, Illinois. The new home to the McDonalds Corporation work headquarters, accelerated project delivery methods were essential to meet the scheduling demands for this project along with other projects slated to start in the region. As such top-down construction methods were utilized to allow for above and below grade construction to proceed in parallel in lieu of more conventional bottom-up construction methods, thus compressing the project schedule. To achieve this plan, perimeter secant pile walls were constructed in conjunction with interior columns/drilled shafts and a shear wall core constructed from inside a temporary cofferdam. The use of secant pile walls allowed for efficient accommodation of a variety of loading conditions including: exterior curtain walls loads, perimeter column loads, tower crane foundation loads, and in-plane shear loads. Furthermore, this system allowed for efficient and fluid operation of equipment on site in order to accommodate the 90-day window allotted for initial foundation construction. INTRODUCTION 110 N. Carpenter is a recently-constructed 9-story commercial building located on the old Harpo Studios property in the West Loop neighborhood of Chicago, IL. The construction of this 55,750m2 (600,000 ft2) structure is significant to the continued commercial development of Chicago as nearly 46,450m2 (500,000 ft2) of the building houses the new world headquarters for the McDonald’s Corporation, which had moved from Chicago to the suburb of Oak Brook in 1971. McDonald’s recommitment to this urban environment is not only a reinvention of the long-established fast food giant but the anchor for a broader redevelopment of the West Loop neighborhood. Since the opening of this building was seen by the developer, the City of Chicago and others as a key to future local projects, innovative solutions were required to showcase forward-thinking design as well as expedite the construction process. The final result of the design/planning process is a structure consisting of nine levels of above-grade commercial space and two levels of below-grade parking, providing approximately 300 parking spaces. The above-grade structure consists of a reinforced concrete flat plate system, including two-way slabs, columns, and two core/shear wall systems for lateral support. With an average depth of 7m (23ft), the below-grade structure consists of interior components similar to the above-grade structure (structural slabs, columns, shear walls) but includes a perimeter secant pile wall that was designed to support lateral earth pressures; vertical forces from the exterior curtain walls, perimeter columns, and the construction tower cranes; and in-plane lateral forces to reduce the demand on and quantity of interior shear walls. The use of a secant pile wall is a key component to the project because it accommodated the use of top-down construction methods to accelerate the construction schedule.

Jan 1, 2019

By Jeffrey M. Taylor, Arturo Ressi di Cervia

"Construction of the drilled shafts for the Brightman Street Bridge Replacement Project were not only challenging due to working over the water but were also challenged by changed soil conditions, concurrent work being performed by an adjacent contractor on the same project, environmental restrictions and severe winter conditions. A total of 36 x 8 foot (2.44m) diameter drilled shafts with 7.5 foot (2.31m) rock sockets were installed for the East and West bascule piers. This project also included Osterberg Cell load testing on two production drilled shafts at both the East and West bascule piers. The results from the load test program were used to fine tune the design of the drilled shaft rock sockets. From a constructability standpoint the reverse circulation drilling method with a pile top drill rig proved to be an excellent choice for drilling the overburden and rock sockets of the large diameter deep drilled shafts. INTRODUCTIONThe replacement Brightman Street Bridge spans the Taunton River between Fall River and Somerset in Massachusetts.The new crossing is located approximately 1500 feet (450m) upstream from the existing Brightman Street Bridge, which was built in 1908. The new mainline bridge includes nine spans totaling 1725 feet (525m). A bascule type moveable span will be located in the middle of the Taunton River and provide a 200 foot (61m) open channel centered about the 400 foot (122m) navigational channel. The bascule span, which has a span length of 409 feet (124.7m), will be a trunnion-type four leaf structure with a solid deck. A site plan is shown in Figure 1 Contract 3, which includes construction of the foundations for the East and West bascule piers, was bid on December 19, 2000 and was awarded to Modern Continental Construction Company (MCC) on January 24, 2001. MCC in turn awarded the subcontract for the installation of the drilled shafts to TREVIICOS Corporation, which started mobilizing in June of 2001.The scope of work for the drilled shafts of Contract 3 consisted in installing 18 drilled shafts in three rows on each side of the river to support the bascule piers located in the middle of the Taunton River.The foundation plan for the bascule span is shown in Figure 2."

Jan 1, 2004

By Ali Nasirian Ph. D., Gabriel Carvajal

To facilitate the safer and more secure transportation of inmates from San Diego Central Jail to the new San Diego Courthouse, the County of San Diego committed to building a new transfer facility as part of the downtown developments. The transfer facility includes a three-story underground structure adjacent and connected to the Central Jail and a 60-ft deep, 23-ft diameter, 320-ft long tunnel. The tunnel starts at County Jail, passes underneath Western Regional Detention Facility (Old Jail) and, ultimately, connects to the State Courthouse. Condon-Johnson & Associates, Inc. (CJA) was selected to install the temporary shoring shaft for the underground structure as well as three arrays of canopy pipes to support the tunnel’s Sequential Excavation Method (SEM) construction. CJA installed the rectangular 56-ft deep access shaft shoring with three levels of bracing, and a combination of secant piles, soldier piles, and timber lagging. The shoring also included a sliding bridge at top to provide access for trucks to enter and exit from county jail during the duration of construction. Following shoring and shaft excavation, CJA installed and grouted 7-5/8” dia. canopy pipes in 3 reaches, parallel to the longitudinal design line of tunnel with a slight lookout angle. CJA installed 24 each canopy pipes, 99-ft from face of shaft at reach 1, 21 each, 80-ft length canopy pipes at reach 2, and 21 each, 75-ft length pipes at reach 3. CJA confirmed canopy pipe alignment via Inertial Sensing Gyro. To mitigate the possibility of settlements caused by the tunneling operation underneath Old Jail strip footing and grade beams, CJA also performed void fill grouting. Sleeve port grout pipes (SPGP’s) were installed inside the Old Jail basement and grouted with the use of packers as the tunneling operation passed underneath the Old Jail. In detailing various aspects of the construction, this paper aims to magnify the innovative solutions for shoring, canopy pipe installation and void fill grouting challenges as well as the state of the art quality control measures undertaken by CJA.

Oct 1, 2022

By Alexander Ciccone, John H. Gill

Jet grouting is a highly versatile ground modification technique that can offer significant commercial and technical advantages over traditional concrete pit underpinning applications. Despite these advantages, jet grouting remains an underutilized technique in the construction industry due to its perceived complexity, cost, and risk. When performed thoughtfully, underpinning by jet grouting offers significant safety and schedule advantages over traditional underpinning approaches. The New England construction market has seen a recent acceptance in the use of jet grout underpinning on congested project sites across a variety of subsurface conditions. The reduction of the cement batch plant footprint due to equipment advances has allowed the use of this technique in urban sites where its use would be previously infeasible. Furthermore, jet grout underpinning has been utilized for support of historic and sensitive structures with generally lower tolerance to settlement than is typically feasible with conventional pit underpinning. Robust, real-time geotechnical instrumentation monitoring systems have helped reduce the uncertainty and further expand the feasibility of jet grout underpinning applications. When properly designed and constructed by qualified and experienced jet grouting contractors, the flexibility of soilcrete for design and construction may be utilized to overcome the many inherent challenges which complicate underpinning and earth retention systems. INTRODUCTION The construction of buildings and infrastructure in our increasingly dense urban spaces often requires excavations below the elevation of existing structures immediately adjacent to the proposed work. Where a proposed excavation system encroaches into an existing structure’s zone of influence, additional measures, such as the construction of an underpinning or excavation support system, are required to safely excavate and minimize the impacts on the adjacent structures. Jet grouting is one method of underpinning that offers significant commercial and technical advantages over many other techniques. Though it was first used to the United States in the 1980s and has grown in popularity elsewhere, jet grout underpinning remains underutilized domestically due to its perceived cost and risk premium. Jet grouting has significant technical advantages over other underpinning methods due to its applicability in a wide range of soil types and its flexibility of design and installation. The jet grouting process is capable of limiting the movement of foundations during construction and excavation to lower thresholds than most traditional underpinning methods (Droof, Furth, & Scarborough, 1995). Its use for underpinning historic and sensitive structures with lower settlement criteria provides additional evidence to its technical utility. Through thoughtful design, adequate planning, and experienced installation, jet grouting can be an appropriate underpinning solution that can provide significant cost and schedule savings.

Jan 1, 2019

By Sudhir Kumar Das

"The exorbitant price of the land in the metropolis has restricted the horizontal expansion and compelled the owners, the developers and the engineers to opt for vertical expansion. This has resulted in the construction of high rises by extending floors of the existing buildings and developing the new ones for which deep excavation is a must. The multistoried buildings up to a certain height can be founded on shallow depth if the soil beneath can withstand the load. If not, the soil can be stabilized by the latest improvement technology to change the properties of soil to cater the desired load of the superstructures. By such practice the cost and time of completion of the substructures can be reduced in comparison to the substructures needed for deep excavation.The necessity of deep excavation cannot be ignored to create housings, underground parking lots and the other public amenities for the urban migrants in the metropolis.Although most of the metropolis have underground mapping the developers, before starting excavation should be hundred percent sure about the alignment and depth of the utilities so that the excavators do not snap the same to bring cut in water supply, power lines, telephone lines etc, resulting in hue and cry in the neighborhoods of the metropolis due to no availability of the essential services The building/structures coming on the influence zones of the deep excavation should be monitored in all sequences of excavations. In case of building underground corridors for rail or road through open deep excavation under a traffic road the developers, before commencing excavation should shift/divert the dry and wet utilities coming on the way of excavation to suitable locations. The surface traffic need to be diverted either temporarily to an adjacent alternative road or allowed to pass over a decking built over the trench of excavation for the affected length of construction. The soil support system is necessary longitudinally on the two sides covering the width of trench for building corridors. In case of building substructures of flyovers built at different plots along the alignment of the flyover or a multistoried complex built at an isolated plot, the soil support system would be necessary on all the sides covering the plot of construction.The material of construction of soil support depends on the depth, type of soil and the type of permanent structure to be developed. Probable geo-hazards inviting casualties in the deep excavation projects occur due to caving of soil, leakage of wet utilities, seepage through honey comb concrete surfaces, failure of pump used for dewatering etc. A detailed comprehensive planning, management and determination of the project authority is essential for marginalizing the casualties. These prevent unforeseen expenditure in mitigation and help to control the time and the cost over run of overall project. The engineer at site should be more a professional manager than an engineer at site. He should be conversant with the safety and environment rules and regulations applicable to deep underground projects."

Jan 1, 2015

By Christopher R. Harris

"Considerations are presented for developing and implementing self-hardening slurry mix designs to be utilized in barrier seepage walls. Slag-cement-cement-bentonite (SCCB) slurries are the primary focus, with some comparisons referenced to the more traditional Portland-based cement-bentonite (CB) slurries. Field and laboratory mixing methods are reviewed, including 1) single sack – single mixer method; 2) bentonite slurry mixer – cementitious addition mixer method; 3) bentonite mixer – grout mixer – CB blending mixer method. Major phenomena associated with the dynamics of barrier wall excavation, such as loss of water from the in-trench slurry and consolidation of in-trench slurry are discussed. Other topics touched upon include sand content effects, fluidizers utilized, and chemical contaminants. The role of higher bentonite to water ratio is reviewed, with demonstration of improvement of filtration properties, and an increase of water retention of the final consolidated product.IntroductionSelf-hardening slurry has been utilized to construct barrier seepage walls for many decades. This is essentially a single-step slurry excavation and backfill process whereby the trench-supporting fluid gains strength over a short period during installation and maintains or develops low hydraulic conductivity. The resulting curing slurry becomes the actual barrier wall as the resultant cement-augmented clay slurry now fulfills the dual purpose of both temporary trench stabilization and final cured-in-place product. This eliminates the requirement and expense of subsequent backfill/slurry displacement operations required in traditional barrier wall installations.Self-hardening slurries have been fabricated using a number of various clays, most commonly sodium bentonite, calcium bentonite, attapulgite, and sepiolite. Perhaps due to plentiful high quality sodium bentonite deposits found domestically, the proven excavation stabilization properties imparted from sodium bentonite slurries, sodium bentonites are typically specified for formulating self-hardening slurries in the US. Cementitious materials utilized most commonly are Portland cement and slag (ground blast furnace slag or GBFS). For the purposes of this discussion, self-hardening slurry having a cementitious of Portland will be referred to as CB. Those having cementitious material of GBFS replacing Portland (partially or wholly) will be referred to as SCCB."

Jan 1, 2016

By Yu Chuang, Zai Jinmin, Liu Songyu

"The piled raft foundation is a geotechnical composite construction method, consisting of three elements, piles, raft and soils, which is applied for the foundation in an increasing number. Differential settlements have numerous negative effects on a superstructure in piled raft foundations. Through the analysis of the production mechanism of differential settlements and differential settlements control measures, a method of adjusting pile configurations is presented to control differential settlements. By comparing the measured data and finite element method analysis of one oil storage piled raft foundation, the new method is verified that the differential settlements can be reduced effectively and the inner forces of foundations are more reasonable with varying length pile configurations. The differential settlements can be minimized or even reduced to zero with right pile length.INTRODUCTIONPiled raft foundations are widely adopted for the prominent advantage of limited settlements and adequate bearing capacities. However, there always exits differential settlements in conventional piled raft foundations. The differential settlement is the main cause that produces additional stresses in the structure. Differential settlements have numerous negative effects on a superstructure as well as on a foundation, and should be restricted to allowable limits. How to control the differential settlement is the key interest.An increasing number of structures are founded on piled rafts. For this reason, design strategies that enable an optimized design have a major importance for safety and economy. An optimized design may be defined as a design achieving maximum economy of the solution, that is minimum cost for the installation of the foundation."

Jan 1, 2005

By Michael Kynett, Francke Walberg, Richard Millet, Khaled Chowdhury, Mary Perlea

"Cutoff walls are the most common seepage improvement measure for levee flood control projects throughout California’s Central Valley. Cutoff walls are widely used because they can be implemented within an existing right of way in either heavily urbanized areas with limited access, or in high-value crop agricultural areas. The most commonly used seepage cutoff wall types are soil-bentonite (SB), soilcement- bentonite (SCB), and cement-bentonite (CB). Contract values for cutoff wall rehabilitation projects in the Central Valley range from several millions of dollars to hundreds of millions of dollars, and play a significant role in the reduction of flood risk in urban and rural areas. However, recentlycompleted construction of several levee improvement projects has shown limitations and inconsistencies among the commonly used technical specifications for construction of seepage cutoff walls. These limitations were evaluated by practicing engineers involved in different stages of cutoff wall design and construction. This paper describes the specification areas that typically generate design and construction issues. Recommended improvements to specifications are suggested to address these issues. The paper’s topics include: the applicability of the different types of cutoff wall materials and construction methods, quality control testing requirements, backfill gradation requirements, mixing procedures, and settlement criteria for backfill.INTRODUCTIONFlood control projects on the Sacramento and San Joaquin rivers in the Central Valley region of Northern California consist of a large system of reservoirs, bypasses, and levees. The thousands of miles of levees within the system were largely constructed and raised by local entities as need arose; this construction occurred prior to the development of modern design and construction techniques. The majority of these levees were initially constructed to protect land for agricultural development; however, a significant portion of these areas have become or will soon be urbanized. This urbanization has historically occurred in locations right up to the levee footprint. This expedient form of historical levee construction, when combined with adverse riverine geomorphology, urban development, and productive agricultural regions, has led to a levee systems with severe seepage performance issues in a real-estate-constrained setting."

Jan 1, 2015

By David M. Rempe

The purpose of this standard is to provide a method for testing of cushion materials that leads to uniform results when employed by various organizations and laboratories. The load-deflection characteristics measured using this method are intended to provide input data for analysis of pile driving, as in wave equation analysis of pile driving. It should be recognized, however, that there are several factors which may cause a difference in performance between the test samples under laboratory conditions and actual cushion materials under pile driving conditions. These factors include variations in material properties from sample to sample, compaction and/or deterioration of the materials with use, eccentric loading due to misalignment, confinement effects or the cushion container or inter layered materials, head buildup, rate of loading, etc. In order to obtain representative load-deflection characteristics, therefore, testing of cushion specimens which have been subjected to actual pile driving conditions is encouraged 1 such specimen should be tested at various stages of the useful life of the cushion. The users of the data are cautioned to determine if the particular wave equation program they are using requires either the secant or tangent definition of the stiffness and modulus of elasticity.

Dec 1, 1984

By William H. Walton, Clyde N. Baker Jr., Darren S. Diehm

"A 51-story concrete core and steel frame commercial office tower was recently constructed on the site of the former US Gypsum building in downtown Chicago, Illinois, USA The structure foundation reused several caissons from the demolished US Gypsum building supplemented with new belled caissons bearing on silty clay hardpan. Extensive in-situ pressuremeter testing was performed during the geotechnical investigation to determine allowable bearing capacity and better estimate building settlements. Problems during foundation construction along the south side of the building frame required remediation of two caissons. One caisson was supplemented with micropiles, while the second caisson was abandoned and replaced with a straight-shaft rock socketed caisson. To determine the effectiveness of the repairs, the building foundation settlements were monitored during construction.IntroductionIn 2001, The John Buck Company began development of a new office tower at the southeast corner of West Monroe Street and South Wacker Drive in Chicago, Illinois. The site was formerly occupied by the 18-story US Gypsum (USG) building. Mr. Clyde N. Baker, Jr. (Senior Principal at STS Consultants, Ltd .) served as the foundation engineer for USG which was completed in 1962. The building was founded on a forest of belled caissons bearing at elevation -56 Chicago City Datum (CCD). For reference, the ground surface at Upper Wacker Drive is approximately elevation +20 CCD. The bearing material was a hard silty clay, locally described as Chicago Hardpan. The foundation caissons were designed using an allowable bearing pressure of 16 ksf (766 kPa). In 1996, the USG superstructure was razed, and the three-level basement was converted to an underground parking ramp.South Wacker DevelopmentThe 51-story high-rise building was completed in 2005 with a structural height of 681 feet (208 m), and an internal space of more than 1,000,000 square feet (93 ,000 square meter). The typical floor size is 27, 700 square feet (2, 570 square meter). Renderings of the building are provided in Figures 1 and 2. The largest single tenant is the accounting firm of Deloitte & Touche, which occupies roughly 45% of the building space with over 3,000 employees."

Jan 1, 2005