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By Tomohide Takeyama, Binh T. T. Nguyen, Masaki Kitazume

"Deep mixing columns are widely used to support embankments constructed on soft ground area. Researches on the stability of deep mixing columns were done by some authors when the columns do not simultaneously fail but individually fail at different time. A layer of shallow mixing is proposed to reinforce these columns as a group to increase the stability as well as loading capacity of columned improved area. Two centrifuge model tests were done to observe the effect of shallow layer on reducing embankment displacement as well as on failure pressure of improved ground. Acrylic piles were used as deep mixing columns in the centrifuge tests to avoid unexpected internal failure of columns. The results of centrifuge tests were also simulated by 2D FEM to back-analyze the centrifuge experiments. A good agreement between the centrifuge experiments and the numerical simulations shows that by using a shallow layer reinforcing individual columns, the horizontal displacement at the embankment toe reduces by 60 % and the tilting failure is clearly indicated in columns without shallow layer. Although, no significant failure was observed under the current centrifuge condition, the failure pressure of improved ground was significantly increased with the columns reinforced by shallow layer.INTRODUCTIONCement or lime and soil mixing technique was firstly used in Japan and Nordic countries since 1970s. The technique is used to improve soft soil by increasing its mechanical properties including strength and consolidation characteristics (Kitazume and Terashi 2013). Various researches were done to investigate the characteristics of mixing material due to various factors including types of binder, condition of soil, mixing condition and curing condition (Terashi 1997). On the other hand, many studies focused on the application of in-situ mixing technique such as supporting embankment and underground structure as well as working as the foundation of building and factory (Kitazume and Terashi 2013). In term of embankment supporting, column-type improvement is taken into account for huge applications. Due to loading from embankment, the deep mixing columns tend to fail either external failure (Kitazume and Maruyama 2006) or internal failure (Kitazume and Maruyama 2007). However, the deep mixing columns do not fail simultaneously but instead one by one at different time (Kitazume and Maruyama 2007). Because the deep mixing columns work and fail individually, the strength and stiffness of all columns cannot be mobilized simultaneously. By using a shallow mixing layer fixing the top of deep mixing columns, individual columns may work simultaneously. A combined technology of shallow stabilization and floating-type cement treated columns is used to reduce settlement of a high embankment on soft ground (Ishikura et al. 2007). A research on effect of surface improvement layer on internal stability of group column type deep mixing improved ground under embankment load was reported in the Port and Airport Research Institute, Japan (Kitazume 2011). However, the failure pattern of shallow and deep mixing combined structure has not well studied. This research focuses on the external failure mechanism of the combined structure by centrifuge model tests and back-analyzed simulation using 2D finite element method. The effect of shallow layer on embankment displacement and the yield point of the improved ground is also discussed in this study."

Jan 1, 2015

By Hal W. Hunt

Heavier loading and more efficient equipment is helping to keep driven piles competitive in America. Better Knowledge and testing of soils and support materials make it practical to use higher stresses; this is being strongly promoted by those directly concerned with timber, steel and concrete piles. Readily available point protection is increasingly used to assure penetration of piles without damage to full load bearing capability. Fabric drains are being installed with pile equipment to speed consolidation of soils. Sheet pile configuration has changed; production has been reduced largely because of imports. Dynamic checking of representative piles for load carrying capability is replacing conventional load testing of just a pile or two ? at much lower cost.

Jan 1, 1987

By Suresh Chikati, Gangadharan Santhanam

Twin tunnels were constructed to a length of 863m using TBM in one of the underground metro projects. The tunnels pass through complex geological conditions (soil, rock and mixed conditions). This paper presents the consideration of volume loss and the corresponding ground settlement associated with the excavation of twin TBM tunnels by analytical and numerical methods. Empirical methods were used to calculate the ground settlement induced by the excavation of twin tunnels. The ground settlement values were directly derived from the two parameters: the volume loss and trough width parameter. These parameters are calculated based on the geological conditions at the tunnel face and tunnel overburden. The finite element software, Plaxis 2D was used to model the soil parameters with appropriate geological conditions. Twin tunnel excavation is simulated in Plaxis 2D and the effect of tunnelling on the ground was simulated by percentage volume loss. The suitable line contraction value was applied to the tunnel linings to simulate the volume loss. The surface ground settlement was directly obtained from Plaxis 2D. Instrumentation arrays were proposed along the twin tunnel alignment, to provide the ground settlement monitoring data within the influence zone of tunnelling activities. The derived ground settlement values from analytical and numerical methods were compared with the actual field instrumentation and monitoring data. From the field instrumentation data, the actual volume loss values were calculated. The compatibility of ground settlement and volume loss calculated using analytical and numerical methods and those measured using field instrumentation data is discussed in this paper.

Sep 1, 2022

By Jakub Szary

Excavation and shoring adjacent to the above-grade Gilmore train station and elevated guideway was undertaken in 2019. A perimeter secant pile cut-off wall was constructed to a depth 37 m (121 ft) below ground surface consisting of 1.0 m (3.3 ft) diameter drilled piles spaced 750 mm (2.5 ft) on-center, tied back with soil anchors, and reinforced with W610 steel sections every 4th pile. A bracing/jacking system was also constructed to support 3 free-standing guideway caissons within the excavation. An automated instrumentation program was installed to monitor movements of shoring walls and train infrastructure in real time and consisted of a robotic total station, inclinometers, tiltmeters, strain gauges, extensometers, and anchor load cells. Baseline monitoring was able to establish diurnal and seasonal movements within the structure, strongly correlated with temperature. The system actively monitored various shoring elements and train infrastructure in real time and alerted the project team when values exceeded predetermined threshold values. Remote reconfiguration of the automated system allowed for more frequent monitoring during jacking of Pier 29 in March 2022. Monitoring data was in agreeance with on-site manual surveying results and jacking dial gauges, and proved to be a reliable monitoring system for construction applications.

Sep 1, 2022

By Ryan T. Smith, Anthony Sahj, Alexander T. Darnell

Every second can count when trying to board a departing flight or catch a ride-share to your final destination. Hartsfield-Jackson Atlanta International Airport is in the midst of a project that aims to cut about 13 seconds between automated people mover trains (Plane Train) that move passengers between the terminals and concourses. The project involves extending the Plane Train tunnel west from its existing terminus under the domestic terminal. Working from inside non-public areas of the terminal, Keller North America, Inc. (Keller) incorporated systems of micropile-supported steel beams and grillage to both underpin existing columns prior to tunneling and support open-cut excavation at the tie-in of the new to the existing tunnel. Dewatering aided in mining a challenging section at the start of the drive of the mixedface, sequentially excavated tunnel and an automated instrumentation system monitored the performance of the construction and its impact to the terminal. Cut and cover egress and ventilation tunnels required braced support of excavation.

Oct 1, 2022

By Jan A. Nilsen

This paper describes a key element in the construction of a major project undertaken by Harbourfront Corporation in its efforts to rejuvenate the central Toronto waterfront. The Spadina Pier forms one of the two major structures of the $10 million marina complex. Completed in early 1986, the 150 metre(490 ft.) long by 43 metre(140 ft.) wide pier structure will contain a 320 car parking garage as well as providing the foundation of a 17-story residential tower and a two-story retail/commercial complex. However, the pier structure posed a considerable challenge to its developers due to the the many restrictions imposed on the site by the environmental authorities which ruled out the construction of dykes or the placing of other fill materials on the highly contaminated bottom sediments. In addition, access at the site was restricted by its proximity to the main harbour navigation channel and a grain elevator berth. The original design called for a cofferdam to form an integral part of the finished structure. However, the contractor chose to regard the cofferdam as a temporary structure and proposed to construct the pier in the dry by enclosing the 10,000 square metre(107,600 sf) site with a 450 metre(1480 ft.) long single wall steel sheet pile cofferdom 7.5 metres(25 ft.) from the final pier structure. This paper will describes the design and construction of the cofferdam. Prior to finalizing the pier design, a geotechnical investigation of the shale bedrock was undertaken as well as a small sheet pile test cell program to evaluate the feasibility of driving a Canadian manufactured cold-rolled sheet pile into the bedrock. Relying on the design parameters for the shale bedrock, Foundation designed the cofferdam utilizing a post-tensioned bipod bracing system to resist a 7 metre(23 ft.) hydrostatic head as well as the maximum wind and wave forces expected at the site. The bipod bracing system consists of diagonal H-pile raker piles and verticle pipe piles anchored to bedrock with post-tensioned anchors grouted into bedrock.

Jan 1, 1987

By Peter White

A bridge reconstruction project involved driving pipe piles for the new foundations. Disturbances within soil layers at depth caused sinkholes to open up within the construction site. After a near fatal accident, the pile driving installations were suspended. The solution involved ground im­provement through cement grouting with sleeve pipes and special grout additives to minimize migration of cement grout.

Jan 1, 1997

By Jared M. Green

This paper presents the wall stabilization design and implementation for a 541 linear ft masonry and concrete gravity-type retaining wall flanking the west perimeter of a 7.37 acre parcel in Bronx, New York. This paper will discuss the results of static and dynamic stability analyses performed for the pre- and post excavation phases for the proposed 300 ft wide open-cut of up to 14 ft of contaminated soil below the toe of the retaining wall. The wall stabilization consisted of over 74 inclined drilled and grouted anchor dowels, and 55 tiebacks drilled and grouted to the underlying mica schist bedrock. Three over-lapping rows of jet grout columns were chosen as the foundation solution for the existing retaining wall. This paper focuses on the design, construction and performance of the jet grout curtain wall. The jet grout wall served three purposes: 1) underpinning and excavation support for the removal of contaminated site soils, 2) permanent hydraulic barrier, and 3) resistance against a deep seated failure within the thick clay layer present at the site. The originally designed jet grout wall had unexpected negative effects to the existing retaining wall. The jet grouting program was modified while the Observational Method (Peck 1969) was employed to keep wall movements to a minimum. This paper discusses the diagnostic methods used to determine the cause of retaining wall movement; the implementation of a remedial ground improvement program; the modification to the jet grout installation procedure; and the ultimate performance of the jet grout wall.

Jan 1, 2011

By Yoshio Mitarai, Takeshi Nagatome, Yosuke Tanaka

"This paper describes an application of lightweight soil in a deep water area to stabilize an existing quay wall at the Port of Tokyo. Super Geo Material, abbreviated SGM, is a type of lightweight soil, which consists of dredged cohesive soil, cement and air foam, and is applied in coastal development work, such as port and airport construction. This paper reports a SGM construction project at the Port of Tokyo by using a SGM special plant vessel, which was deployed for the Tokyo International Airport (TIA) Expansion Project in order to achieve large-scale and rapid construction. The key issue in SGM construction is quality control. One key quality issue is control of the mix proportion of SGM in consideration of volumetric changes due to air foam-breaking during pumping and air foam shrinkage due to water pressure when SGM is placed in deep water. A smart technique for placing SGM is also necessary to prevent quality deterioration when SGM is placed in deep water, for example, increased bulk density and decreased shear strength due to water absorption. This paper introduces an actual case of SGM construction with a particular focus on quality control of SGM during construction.INTRODUCTIONSuper Geo Material, abbreviated SGM, is a lightweight stabilized soil which is used in coastal development work in Japan (CDIT 2008). SGM is applied as a backfilling material behind existing quaywalls or above underground structures in order to reduce earth pressure on the existing structure and improve seismic resistance. SGM has been applied in many coastal development projects. In particular, SGM was used at the Tokyo International Airport (TIA) Expansion Project (Haneda Airport) as the backfilling material at a quay wall at the joint between the reclaimed area and pier part in a new runway (Nagatome et al. 2010a & 2010b, Yamatoya et al. 2010, Mitarai et al. 2011). In this project, large-scale and rapid SGM construction was implemented by the special SGM plant vessels within 6 months under the condition of limited construction period.This paper introduces a new SGM construction project at the Port of Tokyo in 2011. This project employed the special SGM plant vessel, “Ryujin Mark II”, to achieve large-scale and rapid construction within a limited period. SGM was also placed in a deep water zone at the maximum water depth of approximately 15 m. Thus, quality control of SGM was a key issue for meeting project requirements. This paper describes the actual SGM construction in the Tokyo Bay area and quality control techniques for SGM, considering volume changes due to pumping and placement below water."

Jan 1, 2015

By Lin Li

A reliability based analysis method for a drilled shaft stabilized slope system is presented in this paper. In the past effort, a deterministic method using the limiting equilibrium method of slices for determining the global factor of safety of a slope reinforced by a row of drilled shafts was developed using the soil arching concept. The drilled shaft stabilization mechanisms for the slope were treated as the drilled shaft induced soil arching, which reduces the driving forces on the down slope side of the drilled shaft. The effect of drilled shafts induced soil arching on the reduction of the driving stresses in the limiting equilibrium slope stability analysis was quantified by the load transfer factor through extensive finite element simulation studies. A semi-empirical equation was also developed for expressing the load transfer factor as a function of the soil properties, including strength parameters and unit weight as well as the slope geometry and soil profile, the location and spacing of the drilled shaft, and the dimension of the drilled shaft. However, due to the inherent uncertainties of the soil properties and the model error of the semi-empirical load transfer equation, a modification of the deterministic method into a probabilistic method is developed in this paper. The Monte Carlo statistical method is used to generate random variables for the soil strength parameters based on the prescribed probability characteristics, including mean, COV, and the probability distribution function. In addition, the modeling error of the load transfer factor is also treated as a random variable in the Monte Carlo simulation method, in which the mean, COV, and probability distribution function for the bias of the semi-empirical equation are used. The developed theories were coded into a computer program for analyzing complex slope geometry and slope profile conditions. Two examples are shown in the paper to illustrate the analysis results of the developed probability approach for determining the reliability of a drilled shaft stabilized slope system.

Jan 1, 2017

By Lin Li

A reliability based analysis method for a drilled shaft stabilized slope system is presented in this paper. In the past effort, a deterministic method using the limiting equilibrium method of slices for determining the global factor of safety of a slope reinforced by a row of drilled shafts was developed using the soil arching concept. The drilled shaft stabilization mechanisms for the slope were treated as the drilled shaft induced soil arching, which reduces the driving forces on the down slope side of the drilled shaft. The effect of drilled shafts induced soil arching on the reduction of the driving stresses in the limiting equilibrium slope stability analysis was quantified by the load transfer factor through extensive finite element simulation studies. A semi-empirical equation was also developed for expressing the load transfer factor as a function of the soil properties, including strength parameters and unit weight as well as the slope geometry and soil profile, the location and spacing of the drilled shaft, and the dimension of the drilled shaft. However, due to the inherent uncertainties of the soil properties and the model error of the semi-empirical load transfer equation, a modification of the deterministic method into a probabilistic method is developed in this paper. The Monte Carlo statistical method is used to generate random variables for the soil strength parameters based on the prescribed probability characteristics, including mean, COV, and the probability distribution function. In addition, the modeling error of the load transfer factor is also treated as a random variable in the Monte Carlo simulation method, in which the mean, COV, and probability distribution function for the bias of the semi-empirical equation are used. The developed theories were coded into a computer program for analyzing complex slope geometry and slope profile conditions. Two examples are shown in the paper to illustrate the analysis results of the developed probability approach for determining the reliability of a drilled shaft stabilized slope system.

By Axel J. Pollak

Since the late 1960's the Interstate Division for Baltimore City (IDBC) has been planning and developing the Interstate Highway System for the city to meet regional planning goals. The principal goals are to provide convenient access to the central business district and the port while diverting through traffic away from these congested areas. Interstate Route 95, an eight-lane highway carrying north-south traffic, has headed the city's priority list; during the 1970's its construction proceeded steadily from both east and west towards the harbor. Closing the final 8800-ft (2670-m) gap under the harbor will complete Interstate 95's construction. This final portion, known as the Ft. McHenry Tunnel project, will be built in nine construction contracts. Construction costs of the complete project are expected to exceed $700 million, making it the costliest single project in the Interstate Highway System. Full funding is being provided initially by the Federal Highway Administration (FHWA), and the Maryland Department of Transportation will re-pay the 10 percent local share from toll receipts within the first three years of operation.

Jan 1, 1989

By Basem Sh. Hazzan

In the last four decades significant effort has been devoted to designing piles in expansive clay soils. Nevertheless, only a scant effort has been devoted to the elimination of heave forces acting on the upper part of lightly loaded piles. For this purpose, an investigation site was established in Karmiel in Northern Israel. On this site sixteen unloaded cast-in-situ piles, both uncoated and coated, were installed in a moderately expansive clay soil in the end of summer 1996. The piles were executed to different depths ranging between 2m and 7m and were observed over a period of 27 months. Another nine unloaded cast-in-situ bored piles were installed at the end of summer 1998 for carrying out pullout tests. These piles were embedded two meters from the ground surface. Results obtained from observations and from full-scale static pull out tests showed that separating the piles from the surrounding clay in the active zone by a twin walled sleeve eliminated the heave forces significantly. The scope of the work is, determining of the elimination degree of the heave forces due to the provision of the above sleeve.

Jan 1, 1999

By Timothy C. Siegel

Given that piles are composed of different materials and installed using a variety of methods, ASTM D 1143/D 1143M-07 Standard Test Methods for Deep Foundations Under Static Axial Compression is justifiably general so that it has as many applications as reasonably possible. There are aspects of the test setup, the test procedures, and data interpretation for instrumented piles (some of which are specific to augered cast-in-place piles) that are either not discussed in detail in this ASTM standard or are not addressed at all. Specifically, the use of variable time hold times can obscure the shape of the conventional load-deflection curve, as well as, influence the interpretation of the ultimate pile capacity. Unload-reload cycles induce additional non-uniform internal axial loads within the pile which complicate interpretation of the strain gage data and increase the potential for errors. Attempts to maintain a constant top load during the hold period can lead to operational difficulties in taking measurements and are technically unnecessary. Residual load has been shown to develop in cast-in-place piles and can significantly influence the axial load distribution as interpreted from strain gage data. The stiffness of cast-in-place piles has been observed to vary with the measured strain, and a constant modulus, as provided by correlation with the unconfined compressive strength of the grout, may lead to a significantly different interpretation of the axial load distribution.

Jan 1, 2010

By Xiong Houjin

In the excavation works of some deep foundation pits within the boundaries of Guang­dong Province of China, though some measures, such as steel sheet piles, diaphragm walls, etc. were taken to protect the walls, the construction of the excavation works was often accompanied by damage of buildings and public facilities, surface settelment. sand boil and collapse of piles. When these happened, only chemical grouting could be used as the most efficient measure for rushing to deal with or rescue the emergencies. Besides, the application of chemical grouting protection wall technique also palys a very important role under the geologic conditions of the coastal areas of Guangdong Province, when applied in the mucky oystershell layer wealthy in water and the deep mud layer, it can not only achieve good results, but also reduce the cost significantly. In this paper, we discuss the water-tight and earth retaining functions of chemical grouting protection wall in weak formation, and introduce the applicable ranges of chemical grouting protection wall in the excavation of deep foundation pits. Some technological principles and design considerations of the construction of chemical grouting protection wall are presented. Different types of protection wall are also introduced.

Jan 1, 1991

By M. Zanotto

[ ] A period of heavy rains caused the river Adda to flood parts of the Valtellina, one of the Alpine valleys of Northern Italy. The exceptionally high waters put under considerable strain the whole system of embankments and levees controlling the river and protecting the adjacent towns and lands. In some places the water breached and washed away the embankments, submerging large tracts of cultivated land, buildings, roads and railway tracks. The town of Talamona, in the lower Valtellina, was hit particularly hard: in its proximity the river overrun and then washed away 300 m (1,000 ft) of embankment (see vicinity map, fig. 2), depositing large amounts of riverbed debris onto over 400 hectares (1,000 acres) of fertile land.

Jan 1, 1992

By D. E. Sherwood

Mr. Tamaro introduced his paper which concerned the construction of foundations for the buildings and related infrastructure of the World Financial Center on a reclaimed shoreline site at the Southern tip of Manhattan Island. This large project presented difficult design and construction problems, both geotechnical and structural. All structures were supported by foundations carried to rock. Two of the buildings were supported by conventional pier (pad) foundations constructed within diaphragm wall cofferdams. The remaining structures were supported by either piles to rock or caisson (large diameter) piles with socket depths drilled through the rock of up to 7.6 metres. Underground services, railway and proposed road tunnels all affected the installation of foundations. The proposed road tunnels for the new six lane 'Westway' would involve an excavation 12 metres deep adjacent to and under three buildings. This problem was solved by an agreement that tower windloads would be taken by the tower foundations and not distributed through the basement walls. This was achieved by a system of battered caissons founded on the rock and arranged so that adjacent caissons were founded in different rock masses. Diaphragm walls were restrained using tie backs. Ground testing indicated an exposure to D.C. stray current corrosion of all underground construction. As a result all of the foundations were isolated from the ground by non-conductive materials. In the case of piles and caissons the reinforcing for the caisson was fully protected by concrete and all outside steel used for the installation of piling was considered sacrificial and not used in the computation of long term load carrying capacity.

Jan 1, 1991

By George W. Little, John Councilman

"The selection, evaluation, and modification of contractor mix designs for self-hardening seepage barriers, completed by the slurry trench excavation method, can be one of the most critical and challenging tasks to ensure the cutoff wall meets the design performance criteria. Contractor mix designs should incorporate all available geotechnical data, including subsurface soil characteristics, groundwater information, and potential site contaminates. However, the pre-construction mix design can have limitations if subsurface data is limited or shows variability from initial investigations. Placement of the seepage barrier material needs to be evaluated during construction to identify in-situ performance. In one particular case study, the self-hardening cutoff wall mix design was evaluated over a one year period followed by a year and a half installation period, in which, a number of adjustments were made to the laboratory mix design during construction due to performance in the field. Installation for the selected mix was monitored on a real-time basis, using quality control data, as well as early strength and permeability results to determine if adjustments to the self-hardening mix were necessary. Evaluation of early results and relationships between strength and permeability were used to make adjustments prior to achieving the final test results for 28-day strength and permeability. Test results of the installed mix illustrated a direct correlation between strength and permeability. Achieving a minimum unconfined compressive strength was necessary to meet the minimum permeability of the seepage barrier. Other determinations conclude that the thorough development of a pre-construction mix design can have limitations even when all geotechnical data and site conditions are taken into account. Understanding early indicators and key strength and permeability relationships are necessary to determine seepage barrier performance and limitations.IntroductionThe evaluation of contractor mix designs for self-hardening seepage barriers was reviewed for one particular case study where a mix was developed using available geotechnical background information, including considerations for impacted groundwater. Following development of the laboratory mix design, the seepage barrier wall was installed over a one and a half year period, where the contractor mix design was evaluated and modified to accommodate field conditions affecting performance. The objective of the project was to cutoff and collect impacted groundwater and prevent the migration of contaminants to the creek running adjacent to the project. The self-hardening seepage barrier wall was installed using the slurry trench excavation method along 4700 ft of alignment and extended to depths ranging from 20 to 85 ft below ground surface, where it tied in with a low permeability stratum or competent bedrock."

Jan 1, 2016

By Jogeshwar P. Singh, Ahmed AlaaEldin, Mohamed Ashour

The presented methodology allows the determination of the response of laterally loaded battered long piles in sandy soils based on the soil-pile interaction. The Strain Wedge (SW) model which was originally developed for laterally loaded vertical piles is modified to assess the behavior of laterally loaded battered piles with the consideration of soil and pile properties. The method predicts the pile-head response and associated p-y curves. The presented soil-pile model accounts for the variation of the direction and magnitude of the batter angles from the vertical position. Unlike current practice, the proposed technique also provides the p-y curves for battered piles in sandy soils based on soil and pile properties (i.e., sand relative density, friction angle, pile geometry, etc.). The proposed methodology has been validated through a number of comparisons with full/model-scale pile load tests. INTRODUCTION The influence of pile battering on the lateral response of piles is rarely studied in the literature. Over the last decades and as suggested by Kubo (1962) and Zhang et al. (1999), a p-y multiplier is applied to predict the response of laterally loaded battered piles from an equivalent vertical one. Several researchers conducted model-scale piles load tests to understand the behavior of battered piles subjected to lateral load (Juvekar and Pise 2008; Meyerhof and Ranjan 1973; Meyerhof and Yalcin 1994). However, such tests were conducted on model piles with diameters less than 30 mm which may not have reflected actual soil-pile interaction. Battered piles are generally categorized as positive or negative battered piles according to the angle of pile installation as shown in Fig. 1. From the small-scaled and numerical models of battered piles, it was found that the lateral capacity of negative battered piles is larger than that of vertical ones. On the other hand, the positive battered piles have lower lateral capacity when compared to vertical piles (Fan-ren and Ji-Ming 2011; Juvekar and Pise 2008; Manoppo 2010; Reese et al. 2004; and Reese and Van Impe 2011).

Jan 1, 2018

By Ray Zelinski

Caltrans sponsored a research project in 1992 which incorporated proprietary and generic pile types. The piles were subjected to axial tensile/compressive loads in deep, soft soils. Descriptions of various pile types and systems, scenarios leading to the proposal to test the systems, and load test results were/will be provided by other presenters at this seminar. Therefore, this paper will focus on the issues surrounding use of test results and proprietary pile systems on Caltrans construction projects. The primary issues facing Caltrans during implementation are as follows: 1) producing pile cap designs for a range of pile types and loads; 2) providing construction specifications which allow fair competition among the system vendors, yet assure design and ultimate capacities; 3) Develop quality control standards for pile system materials and installation techniques which guarantee pile durability for static and dynamic loads; and 4) assure that foundations have adequate lateral capacity.

Jan 1, 1993