Search Documents

By Ting Chinsu

Diaphragm wall with tie-back cable is widely used for deep excavation, especially in the area with high density of buildings. This paper presents the measured earth pressure distribution on diaphragm wall during excavation. The earth pressure cells used in field were successfully installed in deep slurry trench by a new type of simplified manipulator. The sizes of the deep excavation are 26m X 36m on plane and 9m in depth. The construction site is located between two multistorey buildings at the main business section of Beijing city. In this paper the field measurements of earth pressure distribution and the analyses based on the comparison between calculation and measurement are very valuable to improve the current calculation method for diaphragm wall design.

Jan 1, 1991

By G. L. Sivakumar Babu, P. Chaithra

"Raft foundations which are used against differential settlements and for carrying heavy loads can still be subjected to excessive settlements even if it is safe against bearing capacity consideration. Providing additional piles under the raft can reduce such settlements to acceptable values. In addition to settlements, the piles also relieve the raft a part of the total load and thus the bearing capacity of the Combined piled raft foundation (CPRF) is improved. Parametric study of response of piled raft foundation has been conducted and the results have been presented. The study is conducted using finite element based software, PLAXIS 2D. The main objective of the paper is to evaluate the parameters that affect the performance of piled raft for an economical and effective design. It has been shown that piled rafts are an economical solution in foundation design compared to raft foundation, for the soil conditions considered in the paper.1. INTRODUCTIONThe aim during the design and construction process of high-rise building foundations in urban areas is to ensure the lifelong safety and serviceability of the new and existing buildings in the neighborhood. In order to realize this aim in a cost-optimized manner, the combined pile raft foundation (CPRF) was developed (Katzenbach et al., 2005). For the foundation of high rise buildings with good subsoil, the simplest structure considered is a raft. But when the subsoil near the ground surface has low load-bearing capacity, high-rise structures are often rested on piled foundations.A piled raft and pile group serves similar purposes, but there are essential differences between them. A pile group is a set of piles that have a pile cap. The piles would be designed to share the pile load at ultimate state. The pile cap would be designed to link the piles together but the contribution of the pile cap to bearing capacity will not be included in the design. On the other hand, a piled raft is a foundation, wherein piles are provided along with the raft so that the total load acting is shared partly by the raft and partly by piles, rather than being dominated by the piles (as in a pile group). Piled raft foundations utilize pile support for control of settlements with piles providing most of the stiffness at serviceability loads, and the raft element providing additional capacity at ultimate loading (Poulos, et al., 2011). Therefore, piles are included in a foundation for two main design purposes: to provide adequate bearing capacity and to bring down the settlements to an acceptable level."

Jan 1, 2015

By Renato P. Cunha

The paper explores a parametric analysis of a four-pile group in contact (hence piled raft) and without contact (hence standard pile group) with the superficial soil layer, under a combined set of loadings (moment M, vertical V and horizontal H forces). The major design parameters of interest, as total and differential settlements, and raft bending moments and shear stresses are assessed under aforementioned distinct conditions. The slenderness ratio of the piles is also varied along the analyses, allowing the establishment of its influence on the derived parameters.

Jan 1, 2006

By Tom George

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

Jan 1, 2005

By Ronald D. Boyer

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

Jan 1, 2009

"1.0 INTRODUCTIONThese Guidelines reflect the state-of-the-practice of the Deep Mixing Method (DMM) in North America. DMM is an in situ mixing process that breaks down the soil structure; injects binders, fillers and reagents into the soil; and blends them with the soil. DMM is also commonly referred to as Soil Mixing. The final properties of the treated soil in situ are a function of the composition of the native soils and groundwater, the binders introduced, the mixing methods and energy, and the conditions and time of curing. Treated soils generally have increased strength and stiffness and/or reduced permeability relative to the native soils.This document addresses DMM performed by rotating single and multiple axis mixing tools, rotating cutter wheels at the end of a rigid kelly bar, or trench mixing using a rotating cutting/mixing chain around the perimeter of a rigid bar. Binder may be injected through low or high energy (velocity) jets.The treated soils created through wet DMM are heterogeneous mixtures of binder, water, soil, and groundwater. Treated soils produced by dry DMM techniques are a mixture of binder, soil, and the water already present in the native soil.DMM applications described in this document include•,Earth retention•,Liquefaction mitigation•,Groundwater seepage control and containment isolation•,Bearing capacity improvement•,Deep foundations•,Mass stabilization and contamination containment•,Embankment, levee and dam strengthening, and stabilization•,Casing replacementThis document was developed to address deep foundations applications. Use of deep mixing for seepage control is not specifically addressed. The reader is referred to documents prepared by the U.S. Army Corps of Engineers for additional information. Shallow soil mixing and the use of DMM for stabilization/solidification of contaminated soils performed at depths less than 10 feet (3 m) are mentioned briefly. Jet grouting is not covered by these guidelines."

Jan 1, 2016

By Fei-chiu Huang

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

Jan 1, 2010

By Frédéric Rocher-Lacoste

On July 2nd, 2007, LCPC and LOADTEST performed a static loading test with an Osterberg-cell on a bored pile of 1600 mm diameter. The 56.50 meters deep test pile constructed by Trevi Spa for Soares da Costa group, was near the Cacheu river in Guinea Bissau. This test was conducted to validate the design of the foundations of the Sao Vicente bridge; a project undertaken by the Ministry of Public Works of the Republic of Guinea Bissau and funded by the European Development Fund. Sub-surface conditions at the test pile location consist primarily of layers of weak sands and clays. The piles were loaded statically using the O-cell® bi-directional method 25 days after concreting. The maximum sustained bi-directional load applied to the pile was 11.7 MN. At the maximum load, the displacements above and below the O-cell assembly were 6.6 mm and 81.9 mm, respectively. The resulting pile head behavior has been calculated for a combined skin friction and end-bearing load of 29.3 MN. The piles were also instrumented using LCPC removable extensometers, which made it possible to measure the mobilization of shaft friction and toe resistance. The adjusted test data indicated that this pile would settle approximately 12.2 mm for the service load of 12MN applied at the head of the pile. This paper provides a very brief presentation of the bridge project and the test pile instrumentation: LCPC removable extensometers and O-cell® instrumentation. The results are detailed and analyzed herein and the combined use of these two instrumentation systems is a world première.

Jan 1, 2008

By Max Gwynn, Tony Suckling

"The new Wembley Stadium is the most spectacular soccer stadium in the world, built to the highest specifications, using the latest technology and offering visitors an unrivalled match-day experience. Wembley Stadium is the home of English soccer, dating back to 1918 when the British Government began planning a British Empire Exhibition with a stadium as its centrepiece. The Empire Stadium, as it was originally known, was completed in 1924 in just 300 days and cost £750,000 ($1.4m). It was finally closed in 2000.The new Wembley Stadium, which opened in 2006, features fully covered seats for 90,000 fans and a striking arch that sits above the northern half of the stadium. With a span of 315 m (1040 ft), the 133-m (440-ft) tall arch is the longest single-span roof structure in the world. It supports the entire weight of the northern roof and 60% of the weight of the southern retractable roof. This means there is no need for columns within the stadium and ensures unobstructed views.Multiplex Constructions (UK) Ltd. employed Stent Foundations Limited to construct the £10m ($19m) foundations package for the new stadium. The scope of works for the foundation package included the design and construction of all foundations, including all main works piling, temporary works piles for the arch and roof, and tower crane piles. The scope also included trial piling and pile testing, setting out and removal of spoil.Piles were constructed by using bored cast-in-place techniques with both hydraulic and traditional crane-mounted rigs. Stent also installed sheet-piled walls at three locations to the site’s northern boundary. In addition to the main contract works, Stent constructed a £2m ($3.8m) contiguous bored-pile retaining wall within the demolition and earthworks package (Figure 1). This work was carried out as a subcontractor to Griffith McGee."

Jan 1, 2008

By Lisheng Shao

Soil mixing and jet grouting have been widely used to support heavy structures such as tanks, cement silos, and storage buildings. Although the installation methods vary between soil mixing and jet grouting, the end product of soil-cement columns behaves similarly in supporting structure loads. In many cases, soil-cement mass treatment offers the owner savings over driven/drilled piles. This paper discusses the design methodology, production work, and quality control, with supporting figures, of a recent large complex tank farm project. The project consisted of constructing six above-ground steel storage tanks and an approximately 700-foot-long fill slope. The tank farm site is located in an industrial area of southern California, with highly variable subsurface conditions consisting of compressible soils and buried construction debris. The compressible soils necessitated that the new tanks be supported on deep foundations. A test pile program performed previously at the site showed that conventional driven concrete piles were not feasible because of buried construction debris, therefore a soilcrete system was proposed. Site design included evaluating the total and differential settlement and column group bearing capacity under both static and seismic loads. Extensive field and laboratory testing confirmed the design soil-cement strength and modulus of both the soil mixed and jet grouted soil-cement columns. The project operation and quality control programs are also included in this paper.

Jan 1, 2010

By Ramin Motamed, Anna Panorska``, Joseph A. W. Toth

In this study, a dataset of 145 bi-directional and static load tests was used to evaluate the load-displacement response with respect to unit side resistance for drilled shafts comprising fully and partially mobilized data. A total of 612 unit side resistance curves were calculated which included 52 fully mobilized curves showing a maximum response. A new approach using the double tangent method, is proposed in calculating the maximum unit side resistance from partially mobilized load-displacement data. The double tangent method was applied to each load-displacement response to estimate the ratio of mobilized resistance between the intersecting tangents and peak measured resistance. It is observed that as the mobilization of side shear approaches a maximum, the ratio approaches unity. Using the fully mobilized curves, regression models were developed using correlations between ratios of estimated resistance at the double tangent, peak, and maximum measured responses. Regression models are evaluated for the following factors: predominant soil type and drilled shaft construction methods. Comparisons of calculated and measured maximum values of unit side resistance are compared for each model. Although these factors each influence the load-transfer behavior, a single global regression model including all the data showed promise in yielding accurate results.

By Andres M. Baquerizo, Matthew E. Meyer, Carlos Ortiz

"The Metropolitan Miami development, a downtown mixed-use complex developed by Miami-based MDM Development Group, has weathered the economic downturn by adapting to the needs and pressures of the local market. The development (a.k.a. Met Miami) epitomizes the term “mixed-use urban development” with its combination of condominium ownership, rental apartments, hospitality, office and retail components within Miami’s urban core. Initially conceived and conceptualized in 2004, the development has gone through several concept changes. Today, the global USD $900 million development approaches completion.The foundation evaluation, design and construction for this development included the use of innovative and state-of-the-art augered-cast-in-place (ACIP) piles. The testing for these elements included (1) the first-ever, multi-level O-cell load test of an ACIP pile, (2) a world record 5,200 ton (46,261.5 kN) equivalent top load test of an ACIP pile, and (3) continued the advancement of the ACIP pile industry to include the deepest and largest diameter pile installation to date. Those dimensions were up to 36 in (914 mm) in diameter, and 120 ft (36.6 m) deep. The project showed ACIP piles were a proven alternative for structures exceeding 70 stories in South Florida.The development includes four parcels. Met 1 and Met 2 are completed, and the construction of the Met 3 development is just beginning, with completion expected in 2014. Once the Met 3 development is completed, the design and construction phases of the project will have spanned a decade. The Met Square portion of the development, which will be a retail and cinema component, is proposed for the parcel between Met 1 and Met 2."

Jan 1, 2012

By Lawrence F. Johnsen, Marc J. Gallagher

"Micropiles are small diameter, bored, grouted-in-place piles incorporating steel casing and/or reinforcements. The omission of micropiles from most United States building codes has resulted in the application of varying standards for design and installation. The ADSC/DFI Micropile Committee has developed a proposed section for the 2006 edition of the International Building Code (IBC 2006) covering micropiles. The proposed IBC 2006 micropile code section is presented, along with comparisons to existing micropile codes and guidelines. A discussion section is provided to clarify sections of the proposed code. IntroductionMicropiles, defined as small diameter (typically less than 12 inches outer diameter), bored, grouted-in-place piles incorporating steel casing and/or reinforcements, are becoming common foundation elements for new construction, retrofits, and emergency repairs. Developed in Europe in the 1950's and used in United States practice since the late 1970's, micropiles are typically not addressed in building codes, particularly in the United States. As a result, micropiles are often reviewed by building officials to a variety of standards, including drilled shafts, caissons, cast-in-place bored piles, and concrete filled pipe piles. None of these adequately address the unique design and construction aspects of micropiles. Therefore, it became apparent to the foundation design and construction community that a micropile-specific code section was required.To that end, the International Association of Foundation Drilling and the Deep Foundations Institute (ADSC/DFI) Micropile Committee appointed a subcommittee in October 2003 to develop and submit a proposed micropile code section for the 2006 IBC. The subcommittee members included the two co-authors, as well as Tom Richards (Nicholson Construction Company), Tom Armour (DBM Contractors, Inc.), John Wolosick (Hayward Baker, Inc.), Allen Cadden (Schnabel Engineering) and Matt Niermann (Schnabel Foundation Company). At the time of the writing of this paper, the proposed code section has been presented at the IBC public hearing during which it was modified slightly. Final adoption (or rejection) will be determined by the IBC at the final action hearing in September 2005. The attached code section is the revised version following the public review hearings."

Jan 1, 2005

By Peter Smith

One New Change is a landmark retail / commercial development in the City of London. Integral to the structure is the three double storey basement from which the building is serviced. The building construction involved a ?top down? (up down) construction technique to give programme benefits. In addition, the planning authority stipulated that 10% of the energy demand had to be met by Renewable technology. Cementation Skanska has not only delivered the foundation package - comprising secant piling and foundation bearing piles including Cemloc® plunged columns - but, alongside subcontractor Geothermal International, also installed a 1.7MW ground source heating and cooling system using Energy Piles® and open?loop wells to provide the renewable energy. The works were successfully installed and completed within a tight programme, and within the logistical constraints imposed by an inner-city location, concurrent demolition works and multi contractor involvement in the basement construction.

Jan 1, 2010

By F. Keith Jacobson

To be involved in the construction of a deep dredged caisson for a major bridge pier is one of the most rewarding and professionally challenging experiences one can have in the bridge construction business. That experience was doubled in the construction of the two deep dredged caissons for the Highway 82 Bridge over the Mississippi River near Greenville, Mississippi. The challenges and the construction risks associated with constructing these two dredged caisson pier foundations highlight the construction engineering innovation associated with major bridge pier construction. The 1,378-foot Main Span of the Highway 82 Bridge makes it the longest cable stayed bridge span over the inland rivers of the United States. The main piers for this bridge are supported on two dredged caissons measuring 80-feet by 122-feet in plan, founding 200-feet and 170-feet below the river surface. The challenges of constructing these caisson structures, sinking them through 70-feet of water to the river bottom and then excavating and further sinking them to the founding grade without exceeding the design tolerances, were enormous. The construction engineering opportunities for innovation included major breakwater structures to create a friendly environment in 11 fUsec currents, the first time use of Articulated Concrete Mattresses for river bottom scour control, unique air dome design to maximize the buoyancy of the caisson structure while floating, a caisson guide system to assure positive control and positioning of the caisson during the initial sinking phases. and a comprehensive sinking plan to assure maximum control and minimum risk. Many of the innovative solutions to the construction challenges on this bridge will be incorporated into future caisson construction projects on the lower Mississippi River.

May 11, 2007

By Kevin Cunningham

"Litigation resulting from neighboring structures with settlement and/or lateral movement or improper pile design and faulty soils engineering analysis, are a multi-faceted opportunity for law firms. These types of claim scenarios are an attorney’s dream, and can obliterate a Deep Foundation Contractors profit and more importantly, can be avoided with a progressive approach to risk management in design and project management.The following (4) case studies will be examined and dissected to discern certain lessons learned for risk management solutions to avoid these deep foundation related challenges in the future.1) Pipe Flotation – Soil Conditions Not Anticipated in Specifications or Contract2) Easement Encroachment – Easement Dimensions Not Recognized Until Completion of Project3) Subjacent Lateral Support – Neighboring Structure Wooden Pile Unprotected Causing Structure to Settle4) Improper Pile Placement - Construction & Design Caused Retail Store to SettleSpecific Deep Foundation project challenges involving: buoyancy calculations regarding subsurface soil characteristics, design factors taking existing subsurface sewer line easements into account, structural instability as result of excavation causing exposure/heavy rainfall to existing wooden piles supporting adjoining building and improper pile location resulting from faulty pile design will be described with risk management recommendations to avoid these challenges in the future.From the very start of construction on any project deep foundation and excavating work poses numerous engineering and technical challenges for developers, contractors and engineers. Dealing with changing or hidden conditions is one of the most difficult challenges facing any contractor or engineer on a project. Relying on incomplete or inaccurate engineering reports is another common problem. Other challenges include dealing with technical errors or oversights that are deeply embedded in the project specifications or bid process.No matter what is the origin of the problem or how it manifests, deep foundation contractors, design professionals and engineers should be ever-mindful of good risk management practices that can prevent serious disputes that can result in costly litigation."

Jan 1, 2015

By Francis B. Gularte

The Dalles Dam is located 192 miles upstream from the Columbia River?s mouth. As part of an effort to increase survival rates for young salmon migrating downstream to the Pacific Ocean, a river spillwall was constructed to guide the young salmon into the thalway and out of the reach of predators. The spillwall consisted of 43 large precast concrete cells constructed onsite. The 120-ton cells are positioned on the bedrock riverbed to form the 830-foot-long spillwall. Large capacity post-tensioned strand anchors extend through ducts in the precast units, anchoring the wall to the basalt. One hundred seventy-eight tie-down anchors consisting of 30, 32, or 40 strands were installed and post-tensioned to secure the cells. The logistic and technical challenges presented by positioning, installing, and stressing the precast cells in the tailrace of a large dam required a high level of cooperation and planning between the owner, general contractor, subcontractors, and suppliers in order to finish the project within the allotted in-water work windows to minimize impacts on seasonal salmon migration.

Jan 1, 2010

By Bill Shea, Gordon King

"For a drainage channel built in San Juan, Puerto Rico, a value engineering (VE) proposal incorporating a secant pile top-down approach saved time and facilitated construction work on the larger flood control project. The channel, at the Bechara Industrial Area, Puerto Nuevo Port Facility and the Puerto Rico Maritime Shipping Authority Dock, was needed to allow drainage of the Rio Puerto Nuevo into San Juan Bay. The port area, one of the busiest in the Caribbean, has over 6,000 ft (1,800 m) of berthing wharves for ocean-going container ships along with over 500,000 sq ft (46,000 m²) of container loading and unloading areas, and is critical to the local economy.Planners wanted to minimize the impact of construction to the port and dock users, and developed a construction methodology and work sequencing that would prevent a complete barrier to port traffic. This plan involved non-contiguous and limited work area that “leapfrogged” along the alignment so as to prevent long barriers to lateral traffic movement across the culvert alignment.After reviewing the project plans and schedule, Morris-Shea Bridge Company (MSB) proposed an alternate design and construction approach that provided significant cost and schedule benefits, and also provided better access for the port and dock users. The alternate VE proposal involved top-down construction methodology and redesigned drainage culvert geometry with two parallel 2,000 linear ft (lf) (600 m) secant walls installed on each side of the culvert. These walls facilitated excavation and formed part of the culvert permanent walls. The result was a significantly reduced required construction right of way that allowed construction work in contiguous areas largely without impact on ongoing port activity. MSB conceived the design concept, and engineered design and construction of the VE alternate secant pile culvert.The project initially consisted of an open channel in the industrial area picking up water from the existing Rio Puerto Nuevo, transitioning to an enclosed culvert through the port and dock areas, and outfall through the existing dock. The base bid construction included three main areas of work:"

Jan 1, 2012

By Shawna Munn, Sarah Speir

Cedarvale Station is one of 25 new Eglinton Crosstown light rail transit (ECLRT) stations along Eglinton Avenue in Toronto. It is an interchange station with the existing Toronto Transit Com- mission (TTC) University subway line and is located at the intersection of two major thoroughfares. The new LRT tunnels run below the existing Yonge Spadina subway line and required total excavation depths of 20 m (65 ft) to facili- tate construction of the new station.

Jan 1, 2023

By Abid O. Adekunte

The design, construction and monitoring of the deep excavation support for the basement of a large-scale commercial development in Cavan, Ireland is presented. Excavation area was adjacent to existing structures and retained height H varied between 4.0m ? 11.0m. In areas where excavation depth H < 5.0m, wall was designed as cantilevered section. However in sections where 5.0m = H = 11m, additional wall supports were required for serviceability reasons. Traditionally, designers often provide additional wall support through the use of tie-back ground anchors, raking props and braces. On the current project, the main contractor was not in support of the use of temporary props so as to maximise working space, while owners of adjacent properties disapproved the use of tie-backs. The limited set-back between the wall line and site boundary also contributed to the complexity of the project. A rare alternative solution has been adopted. This novel approach involved buttressing the wall with steeply raking bored tension piles at regular intervals along the wall. Comparison of the monitored deflections in the cantilevered sections with those recorded at sections where tension piles were used shows the novel solution to be safe and quite effective. This approach is also considered to be more economical when compared with ground anchorage and propping.

Jan 1, 2008