Search Documents

By R. A. Bullivant

Roger Bullivant Piling Limited has started 1992 with the introduction of the CONE PILE into its range of precast concrete foundation techniques. Since the establishment of its Piling Division ten years ago, alongside the original Underpinning Company, a commitment to innovated development has seen a steady growth in Roger Bullivant's activity in piling, ground treatment and general foundation engineering. Over the last four years, £1.2 million has been invested by the Bullivant Piling Division into research and development in the field of precast piling and other foundation systems. The goal has been to develop economically attractive systems tailored to our clients design requirements and, wherever possible, unique to Roger Bullivant Piling.

Jan 1, 1992

By Robert W. Schaut

The use of micropiles is increasing for new construction and to retrofit distressed foundations in expansive soils. Typical micropiles in expansive soils have a lower section where the micropile grout is embedded in direct contact with the soil, and an upper section that is cased with rigid PVC pipe or other material to reduce the friction between the micropile and the surrounding expansive soil. In the upper cased section, the micropile grout is in direct contact with the inside of the casing. During construction, grout can flow upward into the annular space between the soil and the outside of the casing as the grout is tremied into the micropile. Thus, various interfaces may exist in a typical micropile, including soil-to-grout, grout-to-PVC, and soil-to-PVC. As the surrounding soil heaves, shear stresses are mobilized along the interfaces. The frictional characteristics of the interfaces are design variables that must be evaluated. For this study, an experimental program was conducted to evaluate the shear strength of the three interfaces listed above. Conventional direct shear testing was performed at a commercial testing laboratory. In addition, specialized testing was performed at Colorado State University (CSU). For the CSU testing, an interface testing protocol was designed using a modified triaxial cell to allow evaluation of the interface characteristics between rigid PVC and cylindrical specimens of grout or clay soil. It is shown that the shear strength of the soil-to-PVC and grout-to-PVC interfaces are similar, both of which are significantly lower than the shear strength of the soil-to-grout interface. This indicates that the use of a PVC casing in the upper portion of a micropile has a positive effect in reducing friction and the shear stresses resulting from expansive soil.

Jan 1, 2011

By Patrick O. Shires, Harry W. Schnabel

With stable building sites becoming scarce in the greater San Francisco Bay Area, the new Summit Senior Care Facility is being built into the side of an unstable hillside adjacent to the San Ramon Regional Medical Center in San Ramon, California. This hillside has had a long history of instability and the site of the new Senior Care Facility required excavation into both a historic old landslide and a more recent active landslide. After a thorough geotechnical study, it was concluded that the best way to build the new facility would be to construct a tied-back retaining wall in the area of the old landslide, since it extended off-site onto two adjacent properties, and remove the active landslide and replace it with compacted fill before cutting into its toe area with an additional tied-back retaining wall. The design was further complicated by the proximity of the site to several active faults. In the area of the old landslide, the combination of an ascending slope behind the wall, landslide forces and seismic forces resulted in total design pressures between 365 to 4,575 PSF for a wall with a maximum height of 30 feet. The wall for the old landslide was constructed by first drilling and placing steel soldier piles in concrete. The tip of the soldier piles extended a minimum of 12 feet below the landslide plane that was up to 36 feet below the bottom of the wall. Permanent double corrosion protected tiebacks were then installed through the soldier beams and anchored below the slide plane. A shotcrete facing was then installed on the face of the wall. BACKGROUND The site of the Summit Senior Care Facility is located on the southwest flank of Mount Diablo adjacent to San Ramon Valley which is characterized by gently rolling hills. The San Ramon Valley Regional Medical Center, which opened in 1990, is located to the north and an existing church is located to the southwest. There are also private residences located to the southeast. The site is shown in Figure 1. Numerous faults run close to the site, the most significant of which are the Calaveras and Pleasanton faults. The site has also had a long history of slope instability and has been the subject of numerous investigations. Studies conducted in 1979 and 1984 concluded that there was a landslide in the area and recommended that a buttress shear key be constructed between the subject site and the existing church for a sewer main as well as removal and replacement of the head area of the old landslide to stabilize the hospital site. While two previous geotechnical studies in 2008 and 2016 identified slope instability, they did not recognize the genesis and limits of the old landslide on the western portion of the site or the limits of the active landslide on the eastern portion of the site.

Jan 1, 2018

By Hodjat] [Shiri

A 4-legged jacket structure was installed by an Offshore Installation Contractor (OIC) in the Persian Gulf. In addition to four open-end pipe piles, six conductors were installed by OIC. During the installation of the piles and conductors, some cemented layers were encountered, which had not been accounted for in the foundation design performed by an independent well known offshore geotechnical site investigation contractor (OGSIC). Six months later, the Drilling Company (DC) hired by Client to execute the wells, reported that all of the six conductors were presenting anomalies, such as vertical misalignments up to 10o and/or collapse of the conductors tip and mid height. The DC faced with serious problem in drilling of the wells and in spite of several times milling the conductors and spending 40 days unpredicted extra time, some of the routes could not be opened and Client lost millions of dollars due to direct and indirect associated costs and expenses. This paper presents a complete overview of all engineering, construction and specially geotechnical investigations and shows that how an inaccuracy in interpretations of the results of an offshore geotechnical site investigation as the main reason in this case study can cause serious damages to whole project with unbelievable time and cost impacts some times up to millions of dollars.

Jan 1, 2006

By J. Brian Anderson

Jointed micropiles were investigated to support bridge foundations where shallow rock was present. In this application, micropiles would have some amount of unsupported length, and would be subject to nominal lateral loads. Five lateral load tests were conducted on micropiles to demonstrate the impact of casing joints and rock socket embedment on lateral behavior. Load tests were simulated with FB-Multipier, a hybrid-finite element program for analysis of deep foundations, for proper design of the loading apparatus and instrumentation. The micropile sections were 2 m (6.56 ft) long, 273 mm (10.75 in) in diameter, 13 mm (0.5 in) thick walled, with a 50-mm (2-in) long threaded joint. Micropiles were made of one to three casing sections and were embedded 0.3, 0.6, 1.5, or 3.0 m (1, 2, 5, or 10 ft) into rock. In each test, two identical micropiles were pulled together using a simple frame until the weaker pile failed. All micropiles were instrumented with inclinometer casings while two contained strain gages at 0.76 m (2.5 ft) intervals. Load and displacement were measured at the pile heads. Tests showed the embedment of 0.6 m, 1.5 m, and 3.0 m (2 ft, 5 ft and 10 ft) sufficiently carried lateral loads over 180 kN (20 tons). The piles embedded 0.3 m (1 ft) were not able to maintain lateral load. In general, all micropiles tested to failure exhibited a brittle failure mode where there is small lateral deflection followed by a sudden failure at the casing joint. This was demonstrated in three of the load tests. In most cases, the micropiles were stiffer and stronger in the load tests than originally predicted numerically. The final test, where piles were not loaded to failure, verified that embedding vibrating wire rebar strain meters in the grout captured the bending moment profile of the micropile. The results showed the maximum moment in this case being carried directly across the threaded joint as predicted by the preliminary models. The results of these tests were used to calibrate the FB-Multipier numerical model. Using a load test that included bending strain measurements for a match, the soil properties were adjusted to produce reasonable matches for all of the load tests.

Jan 1, 2011

By Gordon King

The City of Atlanta Water Department required the construction of a two sludge tanks and a wet well at the existing Chattahoochee Water Treatment Plant. Western Summit won a design build contract to build the project and proceeded to evaluate the wet well size options, and construction procedures. The final design required the construction of a 1 million gallon tank. The proximity of the underground tank to adjacent roads and existing plant structures ruled out laying back the excavation. As a result a tied back sheet pile retaining wall was initially proposed.

Jan 1, 2003

By Shahid Islam, Lucian Bogdan

There is a rapid expansion of world’s infrastructure and simultaneously existing infrastructure is aging. The maintenance of infrastructures has been of particular concern to the engineering community. Monitoring and evaluating the structures have become more significant than ever. Ground anchor is an important part of the structure where it is installed. Unfortunately there are limited testing methods available to assess the force in the pre-stressing steel. High cost, complicated equipment and limitation of space often prevent these methods from being implemented. DYNA Force sensors have been developed to measure the force in the pre-stressing steel during construction and at any time during the lifetime of the structure. These sensors make use of the magneto-elastic properties of ferrous materials. A readout unit is designed to magnetically energize the steel through the sensor and measure the response of the steel to the process. The readout unit then converts the response into a direct force reading. They can be used for bare, epoxy- coated, galvanized and greased-sheathed steel in the bonded, un-bonded, grouted or un-grouted length of the tendon. It measures the force of the steel element at the location where it is installed and can be recorded manually, automatically, or remotely. The sensor is robust, requires no maintenance and it is expected to have a similar service life to that of the surrounding structure. Sensors have received attention in terms of accuracy, performance, ease in installation, durability, and cost effectiveness. Sensor readings provide a second measurement, in conjunction with the jack pressure gauge, of the post tensioning force during initial testing procedure for ground anchors. This paper describes its application in tie-back and tie-down anchors and force monitoring of retaining walls, bridge abutment and dams where the data were collected manually, automated and remotely. INTRODUCTION Our infrastructure is expanding and the existing infrastructure is aging. Some structures are expensive to maintain and some occasionally fail. There is a large demand for implementing health monitoring of structures. Many tie-backs, retaining walls, dams and other geotechnical structures are post-tensioned and many of them need repair using a post-tensioned system. On many occasions during construction and service life of the structure, it is useful to know the force in the post-tensioning and anchor system. Many piles and drilled shafts are designed using reinforcing steel and the compressive forces in reinforcement are unknown. Although there are many methods to measure the tendon force, most of them are cumbersome, expensive, and the accuracy varies depending on the method used.

Jan 1, 2018

By Peter Florian

At 5:50 am on October 1, 1992, the new $800 million Pittsburgh International Airport Midfield Terminal opened its gates to the world after five years of construction and more than 24 years of planning. Despite numerous design changes, this massive project was completed on time and substantially within budget. The importance of this airport to Allegheny County and the Pittsburgh region was recognized 24 years earlier by Allegheny County Commissioners Tom Foerster and the late Leonard Staisey. Staisey and Foerster established a program to acquire land for the "Airport of the Future".

Jan 1, 1993

By Richard Crockford

The World Trade Center (WTC) is located on the west side of Manhattan in New York City, approximately 0.5 miles north of Wall Street, and is owned and operated by the Port Authority of New York and New Jersey (PA). As part of the WTC site redevelopment the New York City Transit Authority?s No. 1 subway line which runs through the site below grade, was underpinned so that the soil beneath it could be removed along with the rest of the new east basement excavation. Consequently a scheme comprising micropile installation through and around the existing subway box was designed. The subway had to remain in use throughout save for planned weekend outages to allow a portion of the underpinning to be fitted through or on to the existing structure. At times this involved accessing and drilling from within the subway tunnel under short General Order (GO) Subway shutdown periods. At either end of the subway passage through the WTC site jet grout underpinning was designed to provide support and to complete the excavation and construction of the east basement wall in the areas beneath the subway where it was impossible to install a slurry wall. The jet grout blocks thus formed had to be largely installed around the clock during 53 hour long GO weekend outages and had to overcome severe logistical constraints in and over the tunnel. The jet grout blocks had to provide strengths of at least 500 psi at 3 days and 700 psi at 28 days. The jet grouted soil mass also had to have a level of permeability less than 0.03 feet/day (1 x 10-7 m/s). After an extensive trial program and then production testing it was concluded that the glacial till above the rock proved to be a particularly difficult soil strata to collect test data from and hence the level of observational monitoring was increased to progress the excavation works. Throughout the installation of micropiles and jet grout columns extensive monitoring was in place and prompted a variety of working method changes. The work described in this paper was performed by the Nicholson Construction Company/EE Cruz Joint Venture.

Jan 1, 2008

By Nino Catalano

The combination of two top levels of cross-lot braces designed and installed to act as a truss, and vertical post-tensioning of the panels allow the unbraced excavation of a 36' span. Philosophy of Excavation Support System The excavation of interest is for the cut-and-cover box sections of the southern approach to the Third Harbor Tunnel, which is part of the Central Artery/Tunnel project in Boston, Massachusetts. The 60' deep excavation is located very close to an existing building which is supported by piles, as shown in Figure 1. Therefore, it was necessary to minimize ground movement which may damage the building.

Jan 1, 1994

By Martin B. Hudson, Daniel Brescia, Zhangwei Ning

Due to the complexity and sensitivity of surrounding environments, instrumentation and monitoring (I&M) is critical for many urban deep excavations. The objects to be monitored include shoring bulkheads, retained embankments, adjacent buildings and roads as well as underground utilities. However, there are also plenty of constraints on the implementation of I&M such as: congested site space, difficult access to instruments, coordination among multiple contractors, and installation permits for private or public properties. Because of these constraints, sometimes the implementation of the initially planned I&M is delayed, its scope is reduced, and/or the continuity of monitoring is interrupted. For these reasons, it is important to implement the I&M with robust and redundant capabilities while providing minimal interference to the project construction and schedule. This paper describes state-of-the-art I&M technologies including automatic motorized total station (AMTS) with camera and automatic leveling device, reflectorless AMTS and IoT- based wireless sensors based on a case study of an on-going deep excavation project. INTRODUCTION In urban environments, deep excavations requiring the construction of temporary shoring bulkheads are becoming increasingly common, with the associated need to provide protection of the surrounding built environment during construction. Protection of the surrounding environment requires planning, engineering, construction, monitoring, and excessive shoring movement mitigation. The I&M is a vital component of the deep shoring implementation. In public projects, geotechnical I&M is often placed within the general contractor’s scope, whereas the majority of deep excavations are privately undertaken. For those private developments, sometimes the developer contracts the geotechnical I&M directly with the project geotechnical engineer or by a geotechnical I&M specialist hired by the project geotechnical engineer. In either the public project or private development case, the effective deployment of the I&M system relies heavily on coordination and collaboration with the project contractor.

Jan 1, 2018

By W. G. K. Fleming

The general history of piling is traced up to the present time with regard to the evolution of methods and materials. The processes have been strongly influenced by developments in basic equipment and industrial change. It is noticeable that in the twentieth century more progress has taken place than in the many previous centuries. It has been strongly influenced by the general development of Soil Mechanics. Test loading is probably the most effective way to assess the success of designs and many empirical relationships have been challenged through it. As we approach a new century it appears that it will be an age of rapid equipment development, with much enhancement of understanding of what has been done. Processes of automatic construction and testing will becoming commonplace. These changes will narrow the limits of conventional scatter that have come to be accepted and to a large extent will be driven by political efforts to curtail energy consumption, to raise standards of quality and reliability, and to conserve the environment. 1. Ancient history. Piling is an ancient art. Its first mention in history is from Herodotus, the first person to commit an account of his times to the written word in the years 557 to 479 BC. He evidently had a strong interest in engineering matters because he wrote of building, brick making, reinforced brickwork, river training, canal building, bridge construction, tunnelling and its acoustic detection and piling. The piling reference comes from Book 5 at paragraph 16.

Jan 1, 1999

By Franz-Werner Gerressen

"The use of soil improvement to utilize areas, which are not suitable for foundation purpose, has a long tradition. Due to the increasing demand of foundation works in areas of unsuitable soils, the improvement of the existing soils becomes even more important in the future.Various applications and systems for various demands exist around the world. Either it is a “simple” improvement for settlement reduction or a more important aim as liquefaction mitigation. However, each system has its advantages, limits and needs.Furthermore to the soil improvement, using various tools, soil mixing can also be used for applications like cut off and/or retaining wall.The paper will describe some basics of various techniques and different applications of the systems all over the world where the systems provided solutions for different purposes, e.g. simple foundation or liquefaction mitigation.It will describe also the main equipment which will be needed to execute these works under the various conditionsINTRODUCTIONSoil mixing is a methodology where the soil is improved by mixing it with cement, lime or other binders in situ by using a mixing tool. This methodology can be used either as wet mixing or as dry mixing. In the more frequently used wet mixing process, usually a mixture of binder and water, maybe with additives, is injected and mixed with the soil. Depending on the type of soil and binder, by the end of the mixing process, a mortar like mixture is created which hardens during the hydration process. In the dry mixing process, the binder is directly mixed with the soil and reacts directly with the existing soil and water.Mixing tools show several versions, so that they are mixing around either a vertical or horizontal axis, mixing in a trench and maybe are jet assisted. Figure 1 shows a classification done by Bruce 2010. Depending on the technique, improvement depth of up to 80 m can be achieved."

Jan 1, 2017

By James W. Weaver

The 2,120-foot long cable stayed Penobscot Narrows Bridge that carries US Route 1 over the Penobscot River between Verona Island and Prospect, Maine is supported on four foundation units, one below each pylon and one at each abutment. Due to varying subsurface conditions along the bridge alignment, the structure was designed to be supported on foundations consisting of high-capacity steel H-section piles (Verona Pylon), a mat bearing on a prepared bedrock surface (Prospect Pylon) and spread footings bearing on compacted rockfill (abutments). The 70-foot by 80-foot (plan area) Verona Pylon foundation was designed to be supported by 288, 430-kip design capacity steel H-section piles (HP14x117, 50 ksi steel) driven through up to 100 feet of dense glacial till deposits containing cobbles and boulders up to 3 feet in diameter. The piles were installed using a single-acting diesel hammer (Delmag D62-22) with a maximum rated energy of 165 kip-ft. Thirteen representative piles were selected for dynamic testing (ASTM D-4945) to verify pile capacity, hammer efficiency and pile stresses. Dynamic testing determined that four different pile driving criteria were needed across the site due to variation in the bedrock and soil resistance below the footing plan area. Approximately 4 percent of the production piles were damaged/rejected due to misalignment and/or damage as a result of encountering the cobbles and boulders embedded in the glacial till. The rejected piles were located randomly throughout the plan limits of the foundation mat. Subsequent structural analyses indicated that the foundation was capable of safely supporting the design loads without the need for installing replacement piles. Evaluation of dynamic testing results with signal matching and pile driving records provided valuable information on pile side and tip resistance. Evaluations were made regarding predicted versus actual pile lengths, pile bearing material, distribution of skin friction and end bearing capacities.

Jan 1, 2011

By Alexander Filotti, Richard Kalson

"In the last decade, the construction industry has witnessed significant changes in the project delivery systems and contractual relationships between the general contractors (GC) and Deep Foundation Specialty Contractors. The Deep Foundation industry, especially including industry specialty subcontractors, have experienced a significant increase in requests that project risks be transferred through contract documents to subcontractors and suppliers with a decrease in margins for the industry. GCs regularly revise their form subcontracts to take into account recent experiences/contractual trends and newly issued judicial precedent, an exercise that is less frequently undertaken by subcontractors and suppliers. These contradictory trends are at the base of the ethical analysis of subcontracts that comprises the subject matter of this paper. Using contracts as a risk management tool in order to mitigate the general contractor’s risks in the context of dynamic changes in the legislative environment will also be addressed. Furthermore, another possibility for risk mitigation for the industry is to actively promote the introduction of the latest technical developments into the contract documents.CONTRACTS’ ETHICSFor thousands of years, ethics have been a constant presence in our lives and have been debated by different branches of philosophy. In modern times, ethics in business started to be an imperative for the success of a globalized economy.“Ethics are standards by which one should act based on values. Values are code beliefs such as duty, honor, and integrity that motivate attitudes and actions.” (Rumbaugh 2004). Some of these values and actions have been carved in legislation in general and in business legislation in particular. More and more, unethical business practices (e.g., corruption) are identified as the root cause of poverty, underdevelopment, and war around the world. In the context of contract ethics, three aspects are of interest:•,Ethics of contract construction•,Ethics of contracting processes•,Ethics of risk allocation in contracts"

Jan 1, 2016

By Dawn C. Tattle

[ ] Panoramic View of Completed Facade Supports The following case history describes the installation of earth retention systems, historical facade supports and structural caissons by Anchor Shoring & Caissons Ltd. at the Air Canada Centre/Raptors Stadium Project in Toronto, Ontario, Canada. The Air Canada Centre/Raptors Stadium project includes a 140,000 square foot office tower, a 20,000 seat basketball arena and their support facilities. The arena within the complex will also have the ability to host hockey, ice shows, concerts and family events.

Jan 1, 1997

By Marco D. Boscardin

Control and mitigation of building response to construction activities are assuming a greater role in design decisions for underground construction. Alternatives for controlling building response have multiplied with the continued development of ground modification methods, better control of construction activities that cause ground movements, and increased understanding of building behavior and response. This paper describes approaches to estimating building response to construction-related ground displacements caused by adjacent excavation and highlights the discussion with several case history examples. Examples discussed includes experiences with two, seven-story historic structures, supported by timber piles with granite block pile caps, which were underpinned in preparation for ground-freezing ground stabilization and tunnel construction beneath the buildings. The elevation of each building column was monitored and elevation adjustments were actively performed during construction. The second example examines the performance of a slurry wall braced cut, 45 to 50 feet deep penetrating through a stiff crust into a soft clay layer and associated building response. This cut was immediately adjacent to two, approximately 15-story office buildings, which were supported by deep foundations founded in the stiff crust.

Jan 1, 2003

By George G. Goble

The use of augercast piles has been limited by the engineer's concern for the structural quality of the installed pile. The nature of the pile is such that its final structural continuity is very dependent on the skill of the personnel that do the installation. Thus, NDT methods have been used to verify integrity and when problems are indicated the available solutions are usually quite costly. If information were available during the pile installation so that immediate steps could be taken to correct perceived problems, the concerns of the engineer could be addressed and the system would gain increased reliability. Pile Dynamics, Inc. has developed a quality control system, the Pile Installation Recorder for Augered Cast-in-Place piles (PIR CFA). This system consists of the following devices as shown in Figure 1. 1) The Control Unit powers the sensors, conditions the signals from the sensors, records all measurements, takes input information from the operator, displays the results, and stores the recorded data on a flash card for later permanent storage and processing. During the use of the system all of the results obtained during a test are seen during recording and can be reviewed on the screen again after completion of the installation. The ability to review the measured information makes it unnecessary to print a copy in the field. Since printers often give difficulty in the construction site environment the ability to review the results quickly after completion of the installation is an important capability.

Jan 1, 1997

By Jouko L. Lehtonen

Sheet pile walls can be sealed watertightly using various methods. The objective of this paper is to introduce a new innovation comprising the use of continuous cement grouting during embedding. The method has been tested on a field test site and installation and permeability features have been observed and analyzed. Installation can be carried out using traditional sheet piling machinery, merely some additional grouting equipment is needed. Installation speed of grouted sheet piles corresponds to that of conventional embedding. The permeability of the tested method is satisfactory in applications where e.g. polluted soil or water has to be isolated from the surrounding environment. In addition, this method can be used for conventional retaining walls where very low permeability is required or for reduction of soil vibration, e.g. close to a railway embankment. The new method to grout simultaneously and continuously during embedding has been developed based on respective innovations on impact driven steel piles.

Jan 1, 2006

By V. M. Troughton

Large diameter bored piles with grouted bases have been adopted for the foundations of the majority of the buildings at Canary Wharf in London's Docklands, including a deep basement car park. The piles are founded in the Thanet Sand which forms part of London's aquifer where water levels are reported to be slowly rising. A special pile test has been carried out to determine the effects of both the basement excavation and a possible long term rise in the groundwater level on the performance of base grouted piles. These effects were simulated by injecting water around the pile toe and thus reducing the vertical effective stress. In this paper the test layout and procedures are described and the results are presented. The test results showed that the reduction in pile base resistance under increased water pressures was less than predicted by conventional design methods based on vertical effective stress. The end bearing resistance was found to be proportional to the mean effective stress.

Jan 1, 1989