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By Vivek Samu, Murthy Guddati

A new method called Effective Dispersion Analysis of Reflections (EDAR) was recently developed to effectively analyze the dispersive waves generated from lateral impact to piles. This paper presents the results of nondestructive length estimation of existing piles through EDAR. EDAR provides a new visualization method for analyzing wave reflections by transforming the response into the frequency domain thus eliminating the need to perform difficult peak picking in the time domain. In addition to being able to analyze dispersive waves, EDAR also incorporates the effects of radiation damping due to the surrounding soil leading to more accurate length estimates. Concrete filled steel tubes of different embedment depths were tested both in laboratory and field conditions. Length estimates obtained were within 10% error margins after careful analysis accounting for the presence of soil effects and effects from pile top reflection.

By Richard Deakin

This case study describes aspects of the design of bridge foundations using 320mm diameter steel tube piles in the vicinity of Montréal, Canada. In this area, these piles are a very commonly used and cost effective solution for deep foundations. Typically they are driven through thick Champlain Sea Clay to bear onto stiff, strong rock. However, in some locations there is a layer of glacial till between the base of the clay and the rock which cannot always be fully penetrated by the piles. There is currently little published information, about the bearing capacity of these piles in the local till, and this paper presents and discusses some pile-test data from a recent project. The nature of the glacial deposits in the study area is presented using information gained from published geological data, the project ground investigations and site observations. The design approach and assumptions are discussed, together with the aims and outcomes of preliminary field driving trials and pile tests. The paper then discusses the results of dynamic tests undertaken on production piles. Bearing capacity factors are back analysed from the dynamic test results and compared against values assumed within the design. Observations are made that designers of future foundations in similar conditions may find informative.

Jan 1, 2011

By Arpit Parikh

"Ground Water or Pore water pressure development in Sandy Soil formation is Critical situation in foundation analysis and design.Moreover it become severe while associated with higher liquefaction probability in river bank areas. It is difficult to find cost optimized solution for liquefaction mitigation under limited budget allocated for the project. Here in these research paper the attempt has been made to have clear picture of liquefaction by using various techniques and field tests. And its mitigation by suitable foundation type. In Bangladesh, On Bank of River Meghana, Power plant structures are proposed. The particular site is full of fine sand having partial silt throughout from EGL to 55 m depth. Hence in addition to Conventional Boring / Drilling operations, CPLT, SCPT, SCHT and PMT had been performed to arrive deterministic effect of liquefaction. By use of Geologismiki software and some excel based programs developed which indicates that Certainly liquefaction occurs under the event of earthquake. By Checking past records of Bangladesh we found, there are small magnitude earthquakes are inevitable and frequent. Hence fourth to overcome the bad effect of liquefaction, the deep pile foundation -Driven Pre Cast Solid Square Pile of 400 mm dia. had been suggested for various types of power plant structures. Which densify the soil and ground will improve in resisting liquefaction.1. INTRODUCTIONA Detailed Geotechnical/Foundation design Analysis had been done to arrive at optimum foundation design solution in highly probable liquefaction zone of Silty Fine Sand near Dhaka City of Bangladesh for proposed 750 MW Cyclic Power Plant. Hence about 24 no. of (Borehole) Boring and Drilling up to depth of 55 m from existing ground level has been carried out. Additionally, 09 nos. of Static Cone Penetration Test (SCPT), 02 Nos. of Dynamic Cone Penetration Test (DCPT), 02 Nos. of Pressure meter test (PMT), 02 nos. of Cyclic Plate load test (CPLT) of suitable capacity with 06 nos. of Seismic Cross Hole Test (SCHT) in boreholes had been carried out. The purpose of PMT and SCHT was to have clear idea about the Seismic behavior - knowhow of site. According to Basic principles of Soil Mechanics and foundation design, it is proved that PMT & SCHT are dynamic test. These tests stimulate field condition of occurrences of earthquake. In later stages of analysis, it is found that site have high probability of liquefaction through use of Geologismiki – Liquefaction Analysis Software. Author of these research paper also felt earthquake vibrations – strong aftershocks during site study where Epicenter of the earthquake was in Myanmar during month of august 2016."

Jan 1, 2017

By Giuliana A. Zelada-Tumialan

Reduced workability and flowability of the concrete through the tremie tubes and drilled shaft reinforcement have been identified as the main causes of tremie-concrete drilled shaft concrete defects. This paper discusses two recent case studies of defective tremie-concrete drilled shafts. The defects (soft inclusions, aggregate segregation, and low concrete strength) were primarily caused by the combined effects of the tremie placing sequence, rapid concrete slump loss, and poor passing and blocking characteristics of the approved concrete mix design. The level of detail contained in the drilled shaft specifications varied between projects. However, even when the specifications incorporated several of the more recent recommendations for tremie-concrete placement, the case studies showed that typical provisions for concrete mix proportioning and placement can be further improved to minimize construction defects such as those described in this paper. Based on the findings of the case studies presented, recommendations for the development of more effective specifications are provided. The recommendations include requirements for mock-up testing of proposed concrete mix designs and evaluation of the tremie-concrete placement sequence. Performance of such testing and evaluation would greatly reduce the potential for drilled shaft defects and consequent time and financial burdens associated with them.

Jan 1, 2009

By Fredrik Sarvell, Leo-Ville Miettinen, Veli-Matti Uotinen

"Abstract The continued concentration of building activities in cramped areas of city centres means more underground construction and facilities. Demand to minimize execution time and any kind of disturbance to business, general traffic, people and nearby technical structures is increasing. To answer these challenges foundation business has to develop schedule-wise and technically reliable deep excavation and foundation solutions in vulnerable surroundings and challenging soil conditions.Drilled pipe pile wall – RD-pile wall – is a combination of Ruukki drilled steel pipe piles and interlocking sections. Individual RD piles, typical diameters between 219 mm to 610 mm, are connected to each other with interlocks welded to the piles on the automated welding line at the workshop. The matching dimensions of the drilling system and interlocking sections allow the installation of RD piles through stones and boulders and even into the bedrock, if necessary, in a single operation. Installation is done by a down-the-hole hammer (DTH) using the centric drilling system and oversized ring bits or a drilling system consisting of a pilot bit and reamer wings.RD-pile walls have been used as permanent and temporary retaining walls for different kinds of demanding excavations and structures, such as bridge foundation, as quay wall and as sealing structure in rehabilitation of an existing dam. Rigidity and watertightness of the lower end of the RDpile wall is being researched as well as fire design issues examined. One of the most fascinating RDpile wall solution is to utilize the wall as a permanent underground basement wall. Reliable and rigid connection to bedrock decreases the bending moment and deflection of the wall and good fire resistance in addition to large variety of pile dimensions and steel grades gives possibilities to design and execute a cost-efficient basement wall and foundations without temporary retaining wall works. 1. IntroductionIn northern Scandinavian soil conditions, installation of sheet pile walls, or even secant pile walls, is often problematic due to the existence of hard and large boulders in the overburden, and especially when the retaining wall structure should penetrate to or into the hard bedrock. On the other hand, an efficient and reliable piling technique suitable for the demanding soil conditions described above, percussion drilling, has been developed since the 1960’s, and especially from the mid-1990’s, when the concentric drilling method with the ring bit and pilot was introduced. A new retaining wall application, the RD pile wall was developed by combining that drilling method with the widely used retaining wall solution based on steel pipe piles and welded interlocks (a pipe pile wall normally installed with vibratory or impact hammers)."

Jan 1, 2014

By Julie Shang, Tim Evans, Michael McDonald, Yu Guo, Bingfeng Xue

Effective chemical grouting represents a technical and economic solution to many challenges related to soil stabilization and blocking the flow of water. Chemical grouts are facing increasing demands in durability, environmental impact and value. To better meet these challenges, a novel and cost effective process was developed to produce a sodium silicate that increases the ratio (i.e. silica to alkali) beyond what has been used in traditional silicate-based grouts. The move to a lower sodium form of silicate was anticipated to have two desirable performance enhancements; a reduction in leachable sodium and improvement in the durability of the silicate grout. An in-depth study was performed at the University of Western Ontario Geotechnical Research Centre to quantify improvement in durability as well as other performance properties such as compressive strength. The study began by first modelling the gelation time and reaction kinetics of the high ratio sodium silicate over a range of silicate concentrations using two different setting agents as well as with/without a hardener. As expected, reducing the level of sodium produced a much more water resistant grout. These same formulations also showed a four order magnitude reduction in permeability. Somewhat surprising, test results showed the higher ratio silicate having much higher compressive strength. At the time of this abstract, the high ratio silicate was moving to the trial stage for geotechnical applications while the petroleum industry was further along with several successful field trials for water blocking as well as cement remediation. This paper will review the chemistry, testing and features of this next generation form of sodium silicate. Introduction Sodium silicate based grouts have been used for decades for soil stabilization and water control. Over the years, several silicate-based systems have been tailored for specific application conditions to maximize performance and reduce cost. Past research has also focused on the selection of setting agents and hardeners for silicate grouts. A constant in the development effort has been the grade of sodium silicate. The vast majority of chemical grouts have been formulated using a ~3.2 ratio sodium silicate. As a very brief overview on the meaning of “ratio” and why it is so important to performance properties. The ratio describes the proportion of sand to alkali or SiO2:Na2O used to make different grades of sodium silicate. Comparing a 2.2 ratio to a 3.2 ratio, it is easier to polymerize and set the 3.2 ratio. Upon setting and forming a silica gel, the system has higher compressive strength values and improved durability with a reduced level of syneresis (i.e. shrinkage). This leads to the question if 3.2 is better than 2.2 why not go to 4.2 or higher?

Jan 1, 2018

By N. Aarthi, G. R. Dodagoudar

The improvement of soft clay deposits using stone columns is a well-established ground improvement technique in the western world. This technique has been well documented and has proper design codes for precise execution in the field. The sand compaction pile (SCP) method is a contemporary technique to stone columns and has limited literature related to the strength characteristics of the loose to medium dense sand deposits treated with SCP. The available studies on the SCPs installed in cohesionless deposits focused on the improvement by indirectly assessing the SPT-N values pre- and post-installation of the SCPs. The widespread implementation of the SCP technique in recent years has increased the need for a more direct evaluation of the improvement. Earlier studies in this regard have revealed that the available design solutions are based on the type of installation equipment, their working efficiency, and accumulated field data. However, it is found that there are no generic design codes for the direct estimation of the ultimate bearing capacity of the SCP improved cohesionless deposits. To meet the design requirement for the SCP treated ground, a series of experimental and numerical investigations are performed in the present study to arrive at a direct framework in the form of design charts based on the pressure-settlement response of the treated ground. The developed design charts give the ultimate bearing capacity (UBC) of the treated sand deposit for the known initial relative density (RD) of the deposit, spacing and diameter of the SCPs, size of the footing, and for the specified target unit weight required for the intended application. It is concluded that the design charts will be of preliminary use to the design engineers to directly evaluate the UBC of the SCP improved loose to medium dense cohesionless deposits as part of the SCP method of ground improvement. It is expected to have more field-scale experiments and in-depth analysis before implementing these charts for actual field execution.

Nov 1, 2022

By Kenneth Gavin

Design practice for piles installed in Irish glacial till has developed in an ad-hoc manner, based on the results of un-instrumented load tests. This had led to designers using similar design parameters for both CFA and displacement piles. To address the concerns of industry a series of instrumented pile tests were performed by two Irish Universities. These tests summarized herein, revealed that CFA piles develop higher shaft resistance than piles driven in glacial till. However, they exhibit low base stiffness and the end bearing resistance that can be mobilized at acceptable pile settlement is low. The use of simple non-linear elastic design approaches to predict the load-displacement response is considered. The methods are used to predict the capacity of two large diameter CFA piles installed in glacial till. While the predictions were reasonably accurate at predicting the initial load-displacement of the piles, significant creep settlement developed at higher load levels. The cause of the creep settlement was investigated through the use of plate load tests and the consequences for pile design are discussed.

Jan 1, 2009

By Hyunsuk Yoon, Kiho Lee, Juhyng Lee, Younghoon Jung, Junboum Park

"The environmental double pile method is presented as a device to improve the engineering properties and to clean up contamination of low-permeability soil. This method is one of the novel technologies based on the concept of one step process. It can be applied to low permeable contaminated ground for site reuse. It uses piles to improve drainage, contaminant remediation, and bearing capacity of the ground. To evaluate the on-site applicability of this technology, drainage and strength properties of the environmental double pile were assessed by a series of experiments and numerical analysis. Environmental double pile was found to be a feasible alternative method to improve contaminated soft ground.Korea is a peninsula with many coastal industrial zones. These zones are located in regions mostly underlain by soft ground with low permeability and adjacent to industrial areas that can be contaminated. Therefore, a new region-specific remediation method is required to achieve environmentally sustainable development. This research introduces the Environmental Double Pile (hereinafter, refer to as EDP) for the lowpermeability contaminated ground and focused on both contaminant remediation and soft ground improvement. Basically, the EDP is quite similar to sand compaction pile (SCP). The SCP has been studied extensively to improve soft ground (Braja 1999; Hansbo 1994; Madhav and others 1978; Taylor 1948). But unlike SCP, EDP is filled with oyster shells instead of sand and an inner pile is inserted in the center of this oyster shell filled-zone. Therefore, it is a double pile consisting of the oyster shell pile and the inner pile, as depicted in Fig. 1."

Jan 1, 2005

By Toshio Yonezawa, Helmut Florian, Herbert Kuh, Masamichi Aoki, Takao Koono, Franz-Werner Gerressen

"To increase the bearing capacity of the ground, soil improvement technique is often adopted. One advantage of soil improvement techniques is the fact, that the impact to the environment is low, as the system utilizes the existing soil. Recently, compressive strength of soil improvement gets more into the focus for the use of building foundation. To prevent brittle fracture, which is a weak point of soil improvement, fiber reinforced soil improvement has been developed. Laboratory tests were conducted to examine the fibers suitable for reinforced soil improvement, and examine the optimum mix design for fiber cement slurry. Based on the laboratory tests, polypropylene fiber and cellulosic viscosity admixture was selected. For the laboratory tests a scaled model of CSM mixing head was used to examine the dispersion of the fibers in the ground. Using the CSM mixing head, the outer periphery fibers of soil improvement seemed to be arranged in the vertical direction, toughness performance of the soil improvement could be improved. Furthermore, full scale field test was performed using actual CSM unit, modified to enable the use of fiber mixed slurry. The validity of the material as well as the toughness performance of the soil improvement, determined from lab test results, was confirmed. In addition, it was confirmed that fiber reinforced soil improvement can be constructed appropriately by CSM method.2 INTRODUCTIONSoil improvement technique to improve the strength and deformation performance of ground has been used for a long time. Cement improved methods, with the increase of the deep Mixing Method, which has been disseminated since the 1970's, was often used since. Cement used soil improvement technology has been utilized to stabilize excavations, slopes in embankment and much more. Recently, it can be used for preventing liquefaction by building soil improvement in a grid (Suzuki et al. (1996)), and also as basis of the structure by increasing the compression strength of soil improvement (Yamashita et al. (2011)). Cement used soil improvement method, a technique for mixing the in-site soil and cement, can effectively utilize natural resources, and it can be expected that its use will increase further in the future. Therefore, soil improvement technique will be able to minimize the impact on the environment. Cement improved soil is a mixture of soil particles and cement with high compressive strength but low tensile strength. Since tensile strength of soil improvement is low, brittle destruction occurs. Therefore, it is not possible to use soil improvement in conditions acting with bending stress. If a horizontal impact force occurs in the improved soil, the width of the soil improvement needs to be increased to reduce the bending stress. If preventing the brittle fracture of soil improvement, the width of soil improvement could be reduced, then less resources would be needed. In order to increase the tensile strength of the soil improvement, several studies for the mix of fiber and soil were performed. Victor (1992) indicates cracking deterrent effect by fiber based on laboratory tests. Moreover, based on laboratory tests, Hayasaki (1982) illustrated the effect on the tensile strength of the fiber types, the type of fiber, the diameter of and the length of fiber."

Jan 1, 2015

By Seiji Mizutani, Hirofumi Taguchi, Makoto Yoshida, Hidenori Takahashi, Naotoshi Shinkawa, Kazuo Konishi, Yoshiyuki Morikawa, Masaya Kawata

"The lattice-shaped cement treatment method has been used to improve the seismic performance of liquefied sandy soil in Japan. The efficacy of the method has been confirmed by the huge earthquake in Japan. In the present study, a new method to improve sandy ground by using the lattice-shaped cement treatment method is proposed as a liquefaction countermeasure. It is the floating-type and lattice-shaped cement treatment method, where cement treated soil is not fixed to an un-liquefiable stratum. In this method, a fixed-type structure such as treated soil should be formed at the side of the floating-type treated soil to reduce its lateral displacement. In the study, one-dimensional dynamic response analyses were firstly conducted to confirm the mechanism of the new method. Secondly, a series of centrifuge model tests were performed to demonstrate the effect in a proto-type scale's stress condition. The analyses and model tests confirmed the effect of liquefaction countermeasure of the new method.INTRODUCTIONLiquefaction induced by an earthquake generates sand boiling and ground settlement. Other problems have also been reported, including a decrease in bearing capacity and an increase in the horizontal earth pressure against retaining walls. To prevent these problems caused by liquefaction of the ground, various countermeasures have been proposed, such as cement deep mixing and high-pressure jet mixing methods. These methods have the big advantage of being applicable to ground that contains soil with a fine-grain fraction. Furthermore, the unnecessary displacement caused by the construction can be reduced. In Japan, a lattice-shaped cement-treatment method has frequently been used at many construction sites to prevent liquefaction, where cement-treated piles are intersected to form a lattice, as shown in Fig. 1. The lattice-shaped walls can reduce the shear stress generated by an earthquake, restricting the liquefaction at that location. However, the construction cost of the cement treatment is relatively high compared to other methods such as the sand compaction pile (SCP) method, and needs to be reduced. Therefore, decreasing the total volume of the cement treatment is necessary to reduce the construction cost."

Jan 1, 2015

By Armin W. Stuedlein, Youssef Bougataya

Early stage design of driven piles primarily relies on static analysis based on one or a combination of total and effective stress approaches, the latter known as the method to estimate axial capacity. A database of 85 piles driven in the Puget Sound Lowland region and monitored at End of Driving (EOD) and Beginning of Restrike (BOR) was compiled along with capacities estimated using the CAPWAP procedure. Established soil profiles based on borings with standard penetration tests (SPT), cone penetration tests, and geologic maps were matched with their corresponding unit shaft resistance profiles from the CAPWAP procedure and resulted in more than 1,200 observations. In this study, eight new models were developed to predict the coefficients at EOD and BOR, based on the corresponding USCS categorization. Each coefficient model is formulated using a three-parameter exponential function, calibrated to capture the profile of coefficients with depth. These models could benefit the designer by providing them with a simple, empirical model that accounts for soil type and setup in a smooth, continuous function with depth. A parallel analysis was performed to assess the accuracy and variability of the formulated prediction models to facilitate implementation in load and resistance factor design (LRFD). INTRODUCTION The design of the axial capacity of driven piles during the planning stages of a project is typically based on a static analysis approach. The goals of this approach are to predict the components of capacity, consisting of the shaft and toe bearing resistances, and to assess project concept feasibility and preliminary lengths. In most cases, this analysis is based on empirically-developed methods, such as the total stress method, also known as the method (Tomlinson 1987) or the effective stress method known as the method (Esrig and Kirby 1979; Fellenius 1991). Many other methods, such as those based on in-situ test results exist and rely on correlations of blow counts from the standard penetration test (SPT), and cone tip and sleeve friction resistance from the cone penetration test (CPT), to shaft and toe pile resistances (Schmertmann 1978; Meyerhof 1976; Nottingham and Schmertmann 1975; Nordlund 1963; Eslami and Fellenius, 1997; De Ruiter and Beringen 1979). Although these methods were generally developed using data from specific geological regions, they are often recommended in national design manuals (e.g., FHWA, Hannigan et al. 2006).

Jan 1, 2018

By S. Ali Bastani, Ashley Varni

Design acceleration response spectra (ARS) are directly correlated with dynamic forces and estimated dynamic bridge displacements, which make them a critical aspect of dynamic bridge design. Nonlinear site response analyses are performed for a 1,400-linear-foot bridge site with a SC soil profile at the sides and a SF soil profile in the middle to evaluate the soil profile effects on the bridge analyses. One-dimensional seismic response analysis is commonly performed for site-specific response analysis. SHAKE or similar one-dimensional total-stress equivalent-linear approaches have been used since the 1970s. However, the equivalent linear method has deficiencies when the subsurface soils are susceptible to strain softening. Therefore, various assumptions are made when using the equivalent linear method by practitioners to estimate the SF soil profile site response. With recent advancements in constitutive models, effective stress models have become more popular. Although the effective stress models are generally more complicated and require additional input parameters, they shed further light on the liquefaction mechanism and its effect on the surface ARS. An equivalent-linear one-dimensional seismic response analysis and a non-linear effective-stress seismic response analysis, using DEEPSOIL, were performed to evaluate the ground surface ARS for a proposed bridge site in Orange County. The soil shear strengths were estimated based on cone penetration test results using empirical relationships. The shear modulus degradations (backbone curves) of soil layers were adjusted to match the estimated soil strength at failure. The ARS curves developed from each method were compared to determine the most suitable method for estimating a site-specific design ARS curve for a liquefiable site. Considering that the bridge abutments and the outer bents are founded in bedrock, while the middle bents are founded in liquefiable soils, ARS curves were created for each subsurface condition. Taking into account limitations of the structural analysis software, recommendations were made to combine the multiple ARS curves into a single ARS curve for the structural bridge design.

Jan 1, 2018

By Charles L. Guild

I will add a few facts about the use and development of the Osterberg Test Load Cell and my association with Jorj. I first met Jorj in 1965 when the Guild Construction Co. drove 12" diameter cast-in-place shell piles for him at the Marquette Cement Co. in Nashville, Tennessee. When I met Jorj at the DFI Trustee's meeting in 1985 at Longboat Key, Florida, he showed me a sketch of his idea about using a test cell at the bottom of a caisson to test the end bearing and side friction on a caisson. He had made a successful trial test in Case International's equipment yard and wondered whether a similar device could be made for a driven pile. At first I was skeptical that it could be done but after thinking about it overnight I told him I felt it was feasible and we would do some work on it. At that time, there was a large bridge job going out for bid in Rhode Island using 14" square prestressed concrete piles'. Based on a record of the Guild Construction Co. Inc. driving over 3,000,000 feet of piling on work for the State of R.I., we felt we would have an excellent chance to be allowed to use them so we designed, detailed and fabricated three for 14" square prestressed concrete piles. As things worked out, we did not test them on this job and have not to date.

Jan 1, 1989

By Aditi Sharma, Sumanta Haldar

Scouring of soil is the major concern forthe various hydraulic structures built in the flowing rivers since scouring impacts the bearing capacity of foundations. Hence, consideration of scouring in the design of foundations for hydraulic structures is crucial. Pile groups in bridges are subjected to combined vertical and horizontal loading due to self-weight, live loads, vehicular impacts, wind load, earth pressure, and current. Hence, an assessment of the combined bearing capacity of pile groups subjected to scour is essential for the safety of the structure. This paper aims to analyze the bearing capacity of pile group supporting the bridge under combined loading i.e., Vertical (V) and Horizontal (H) loading subjected to local scour. Three-dimensional finite element model (3D-FEM) of a 3 x 3 pile group embedded in homogeneous sandy soil is established in Abaqus (2018). Mohr-Coulomb plasticity model is used for the soil domain. The pile group is modelled as linear elastic. Finally, V-H yield envelopes are obtained with and without scour. The potential impact of different parameters, such as angle of attack, flow velocity, depth of flow, and different pile length-to-diameter ratios (L/D) and spacing-to-diameter ratios (S/D) of pile group on V-H yield envelopes is studied.

Sep 1, 2022

By Klaus Pöllath

This paper describes mitigating measures and the design of compensation grouting which will be executed from deep shafts of the Amsterdam North/South Metro line project. Due to the specific conditions for TBM-tunnelling in Amsterdam (historical buildings on pile foundations near the tunnel and soft soils with high groundwater levels) tunnel construction necessitates mitigating measures, such as compensation grouting or soil freezing. Züblin developed a special shaft construction method for critical distances to buildings. For the compensation grouting Züblin developed a new software tool, called SOFIA, which controls and visualizes and thus optimizes the entire injection process. This tool significantly increases the efficiency of the injection works while reducing the geotechnical risks.

Jan 1, 2006

By George Machan

Bitumen coatings have been successfully used to significantly reduce downdrag on piles. Thicker coatings of "soft" bitumens can accommodate downdrag so well that very little downdrag load is transferred to the pile. Many of the case histories describe better than 80 percent downdrag load reduction. Bitumen coatings have been used on several projects in Oregon. On the Mocks Bottom Bridge project (see Reference 1), experimentation and instrumentation confirmed the viability of bitumen coatings and provided insights for design and construction. Subsequent bridge projects have used this information and have raised issues to be resolved.

Jan 1, 1989

By A. Fisher

The use of thermal integrity testing to verify the quality of deep foundations has increased significantly in the UK and other world markets over the last 5 years. The introduction of distributed fibre optic sensing to this field has broadened the range of applications in which it can be deployed and the types of foundations which can be tested. This paper presents how fibre optic sensing technology can be successfully deployed in the construction environment the range of foundation techniques to which it can be applied. Alongside developments in the practical aspects of thermal testing, progress has been made in establishing assessment criteria which can be used to evaluate the results. This paper presents recent examples of comparative studies on foundations which include both thermal integrity testing, cross hole sonic logging and intrusive coring. The use of distributed strain measurement during pile load testing presents an alternative means to verify the assessment criteria used for integrity testing. This new approach can achieve comparable results to foundation exhumation or intrusive investigation and at a fraction of the cost. This paper presents the findings of several such studies, highlighting the benefits and opportunities for future improvement of the method.

Oct 1, 2022

By Jay L. Hodkinson

Replacement of an aging twin span river crossing in Vermont required a temporary bridge to accommodate traffic during construction. Soils beneath the temporary approach embankment consisted of very soft organic clayey silt underlain by interbedded, loose alluvial fine sand and silt/clayey silt. Reinforcement was required for the southern temporary approach embankment to limit settlement and to increase global stability factors of safety. A ground improvement design was developed using Rammed Aggregate Pier® reinforcement and was included in the contract documents as an FHWA Category II Experimental Feature. Instrumentation intended to document the performance of the supported embankment was installed. Piers were then constructed and monitoring commenced as embankment and bridge construction occurred. Weekly instrumentation data reports indicated continuing excess pore water pressure, settlement, and lateral deformation of the subgrade soils as the embankment and temporary bridge abutment was constructed. In response to the unanticipated monitoring results, further investigation indicated that significant deviations from the conditions and basis upon which the ground support design was developed were made during construction. This paper discusses these deviations and their specific impacts to embankment support performance, how these deviations occurred, the role that the ground support system played in maintaining global stability, measures taken to limit further detrimental impacts to the embankment, and provides recommendations for contract document preparation and construction oversight to prevent similar situations from occurring on future projects.

Jan 1, 2011

By Masanoub R. Fujioka

A brief discussion of the methodologies involved in dewatering practices, particularly as used in Hawaii in coralline formations. A description of early dewatering practices includes a number of case histories; later dewatering practices also are detailed with case histories. There were disasters and some successes. Grouting generally was not successful. Deep wells are technically feasible and generally the economical solution to deep basement construction.

Jan 1, 1986