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By Wolfram Groh

New underground floors comprising the complete footprint area of the building structure, were constructed under an existing building in sand, located in the Verdun district of Beirut / Lebanon. The works for the rehabilitation and extension of the Verdun 528 building were carried out between December 1999 and August 2000. A restriction of differential vertical movement of existing load bearing walls and columns had to be respected throughout the construction phase of the new basements. Support measures for the building were taken based on a underpinning system with Bauer SVV preloaded micropiles. The specialty of this underpinning job was that the building loads at the time of preloading and excavation of new basements was substantially less than at final stage. The design of the preloading system was particularly challenging in view of the transition from temporary to final load transfer under variable load conditions. Load transfer was based on the Bauer SVV micropile head system applied in several technical variants. Monitoring of levels of structural elements performed throughout the construction works confirmed that the differential movements of adjacent load bearing columns and walls were maintained within the specified limits.

Jan 1, 2002

By Aly M. Mohammad

The design of large diameter drilled shafts in weathered rock has always presented a challenge to the foundation engineers. Degree of weathering and load transfer mechanism through the rock are essential elements required for the design. From the Contractor's perspective specifying the right equipment and estimating the rate of drilling in the weathered rock are key elements for successful construction. The Delaware River Tramway Project has provided an opportunity to address the design and construction of drilled shafts in weathered rock. The Tramway, supported by twin 300-foot towers, will shuttle eight-person gondolas across the Delaware River in about four minutes. Each tower, founded on four high capacity drilled shafts, is designed to resist large axial and lateral loads. At the New Jersey tower, each 7-foot diameter shaft extends 145 feet deep and terminates in weathered Mica Schist. The shafts are situated in the Delaware River where the mud line is approximately 20 feet below Mean Low Water. Below the mud line, there exists a very soft, 20-foot thick layer of organic silt, followed by a 40-foot thick dense sand stratum. Below these sand and silt strata, a 70-foot thick layer of weathered Mica Schist underlies the entire site. Both skin friction and end bearing in the weathered rock stratum were utilized in the analysis to compute the axial capacity. AASHTO and the PennDOT design methodologies were utilized independently during design of the drilled shafts to verify the design. The drilling of large diameter drilled shafts embedded into weathered rock and situated in a marine environment provided a unique challenge in the construction. A permanent steel casing was installed for a specified depth and proper equipment was used to drill and keep the shaft open through the weathered rock. In addition, a 5000 kip Osterberg load test was performed on one shaft to verify design assumptions and confirm the shaft capacity. The results of the test were utilized to establish load transfer characteristics within the weathered rock and to develop foundation design parameters to be used for the remaining shafts.

Jan 1, 2003

By Mamdouh Hamza

The construction of 1200 m length new quay wall located 1,300 m East of the existing Suez Canal bypass and about 1,000 m south of the Mediterranean shoreline is one of the main projects currently under development in Egypt. Due to very weak foundation soil, mainly soft clay, a particular effort, both in terms of design approach and construction feasibility, has been required. The execution of "barrettes" and T-shaped" diaphragm wall panels down to a depth of 65 m and under extremely severe soil condition has been required in order to pass through the upper soft soil and to reach a competent base layer. Very critical and variable hydrological conditions have been also encountered due to the contemporary nearby channel dredging activity, thus increasing the difficulty for maintaining the stability of the slurry trenches opened in soft material. This paper gives a general overview of the project with some emphasis to the most significant design aspects and to the construction of the deep foundation elements.

Jan 1, 2002

By Jason N. Scott

It is now possible using low-cost wireless technology and rugged hand-held devices to record data on site electronically and for that data to be instantly available to others. This could potentially eliminate many problems that traditionally lead to remedial work, such as poor communication and the late detection of non­conformances. However, determining how best to implement such a system and integrate it with the rest of the business process is far from simple. This paper looks at Stent's experience of these issues by way of a case study of the SHERPA system. This is a wireless site data collection system developed for use with rotary bored piling.

Jan 1, 2006

By Roberto Nova

The selection of the Osterberg Cell (O-Cell) technology as the standard testing method for deep foundations of the Railways Po Viaduct in Northern Italy offered a relevant number of field measures on large bored pile behaviour in alluvial soils. The assessment of pile response during such ?non standard? testing procedure was performed through the comparison with standard top load tests on companion piles as well as by numerical models of the tests including a simplified pile-soil interaction scheme. As shown in this paper, the O-Cell technology allowed a careful assessment of the non-linear pile behaviour even at quite small loading levels as those required by a posteriori proof tests on production piles. Simple numerical models proved to be very effective in the simulation and the interpretation of pile behaviour during such unconventional testing procedure.

Jan 1, 2008

By Prodyot Kumar Ray, Sudip Kumar Koley, Aminul Islam, Somnath Banerjee

One of the most important topics in the construction industry is the building of railway embankments. Being such a delicate and significant structure, it is crucial to properly design the embankment and build it while adhering to all statutory criteria and design guidelines. A railway embankment's subsoil condition and fill material, groundwater table, dynamic and static loads during operation, and embankment geometry are some of its most crucial design considerations. This paper discusses the likely causes of the collapse of a railway embankment in eastern India as well as the suggested rehabilitation scheme. It was observed that an embankment collapsed in the aforementioned area during a inccesent rain. Along with the side shifting of a cantilever retaining wall that was positioned at the bottom of the embankment, the embankment next to the railroad track settled vertically. According to the available geotechnical report, the sub soil strata in half of the area adjacent to the embankment profile, where the embankment height gradually decreases from maximum height, is stiff to hard clay with an undrained cohesion value of around 50 kpa followed by dense sand, and the sub soil strata in the other half is soft clay with an undrained strength of 15 kpa. As a result, in the rainy season due to the sudden increase in the water table, the self-weight of the embankment increased and further caused the under-laying soft clay to get squeezed away and settle. Due to this squeeze/settlement effect of the soft clay layer, the retaining wall got disturbed along with the generation of an undulated embankment top profile. As a remedial measure, it is proposed to construct a contiguous bored pile wall at the toe of the embankment to stabilize the slope, and additionally, compaction grouting is recommended beneath the embankment to improve the soft clay. In order to carry out the analysis, certain commercial geotechnical software like Slide, Wallap, and Plaxis 2D are used. The factor of safety of the embankment slope considering the above restoration scheme is adequate under static and seismic conditions.

Sep 1, 2022

By Kozo Takeda, Arashi Shimano

"Dry Jet Mixing (DJM) technique is widely known as soil mitigation technique with small ground displacement during installation comparing with other techniques. Some projects involving sensitive structures, however, require smaller impact than in conventional technique. In order to reduce ground displacement during DJM installation, this paper introduces systematic mixing technique, RD-DJM (Reducing Displacement – Dry Jet Mixing). RD-DJM is characterized by injection nozzle on the rim of mixing blade and fin plate on mixing shaft. These devices contribute efficient collection of injected air toward mixing shaft and result in reduction of ground displacement. The authors demonstrate successful performance of RD-DJM indicating difference between conventional installation and RD-DJM technique.INTRODUCTIONThe Dry Jet Mixing (DJM) method is one of the most common techniques in Japanese deep soil mixing field and characterized mechanical mixing of powdery binder with in-situ ground (dry-mixing technique). It is widely believed that DJM Method has great advantages in less quantity of binder to achieve the desired strength and less waste generation during installation.DJM method can meet the required strength with less binder content than wet mixing. And volume of binder of dry mixing is absolutely less than wet-mixing injecting considerable volume of binder slurry. This means that dry mixing causes less ground displacement compared with wet mixing.As the medium for forced feeding of the binder, the DJM method uses compressed air, which is blown from the mixing blade nozzles to scatter the binder and then recovered through the periphery of the mixing shaft to the ground surface. Because the binder is injected outward from the injection orifice at the root of the mixing shaft, a part of the air may escape to untreated areas due to the blockage of air recovery path around the mixing shaft. Figure 1 illustrates possible escaped air and leakage around installation location."

Jan 1, 2015

By Ilhan Chang, Ernest Nsabimana, Kiseok Kwak, Juhyung Lee, Young-Hoon Jung

"Numerical analyses were performed to analyze the behavior of two different type of suction piles (mono type and group type) under various soil layer conditions (uniform silty clay layer, uniform silty sand layer, and two-layer deposit consisting of clay and sand layers) and lateral loading locations (top, middle, and bottom of the suction pile). According to the results, mono suction pile shows maximum resistance when load is applied on its middle, regardless of the soil layer conditions, while group suction piles varies significantly according to the allowance on head rotation. When head rotation is allowed, the behavior of group type piles become similar to the behavior of mono suction pile. Whereas, when rotation is prevented, resistance is maximized when load is applied on the top head. Moreover, group suction piles show higher efficiency regardless of the ground condition and geological stratum. For further advances, concrete block on the top of group suction piles are suggested as an effective alternative method to prevent partial rotation and maximize ground resistance for group suction piles.IntroductionWith the development of offshore technology, applications and real site installations of suction piles are increasing significantly nowadays. They are generally used as mooring anchors in various floating structures, marine platforms, and offshore wind turbines. According to its convenience in installation and removal, suction type foundations are becoming good alternatives for deep ocean support systems. The bearing capacity is similar to the bearing behavior of ordinary offshore structures (piles or drilled shafts). The most common use of suction caissons is anchors for catenary mooring lines, where the chain angle at the mudline is close to zero (Randolph, 2002; Sharma, 2004).Recently, it is reported that a huge isolated single suction pile can be replaced by a group of moderatesized suction piles (Randolph et al. 2004). A single monopile is easy to be produced and installed in site. It is expected that monopile foundation is not applicable for deep depths because it has a limitation on penetration according to its huge side skin area (i.e. friction). Moreover, stiffness requirements sometimes render thicker pile wall conditions which are impractical to be produced."

Jan 1, 2017

By Z. Q. Bian

The wireline sampling originates from core drilling in rocks. The authors combined the wireline sampling technique with conventional undisturbed soil samplers, including Osterberg sampler, Denison sampler and double tube barrel, and then developed the wireline samplers of WPS, WSS and WSR models. These samplers are able to sample various soils. They reserve all the advantages of the original samplers, and moreover, they are noted with quick hoisting and lowering by wire rope. Therefore, it becomes an efficient new technique of sampling undisturbed soil from deep foundation.

Jan 1, 2010

By Dave Paul

Dam rehabilitation involves a range of design, construction, and operation risks, some of which are not encountered in new dam construction. These risks can have significant impact on project schedule and project budget. Owners, engineers, and contractors need to understand these risks. Existing dams typically were designed in an era of design and construction standards that have been upgraded and changed. Modern standards will impact the construction approach taken and involve understanding the earlier standards. Knowledge of historical standards/practices as well as current design standards and construction methods is valuable for developing and designing rehabilitation components. Construction records and as-built drawings are valuable when they are available. Rehabilitation projects often consist of older projects where as-built documents or construction records are not available. Where these records exist, many (most) times, they do not fully reflect the current conditions within the dam and appurtenant works. leading experienced practitioners to “expect surprises” both during investigation of the existing facility, as well as during construction. “Surprises” should be expected even when historical records of investigations, design and construction are available. Unknowns, be they known unknowns or unknown unknowns, can be planned for by developing an approach for the design and construction process to identify potential issues/problems, or at least alert the designer and contractor of potential issues. A Risk-Based approach applied for the entire life of the rehabilitation project can be used to alert the parties of potential “surprises” and provide direction for mitigating issues as they arise. This type of approach is particularly effective when the process includes senior practitioners with decades of design and construction experience in all aspects of dams. Minimizing impacts created by “surprises”, particularly during construction, can result in an improved project meeting budget and schedule goals and design standards. This paper identifies and categorizes risk types salient to dam construction, reviews the process of risk identification and analysis, discusses guidelines for risk allocation, reviews strategies to mitigate risks, presents several case studies where risk mitigation strategies were employed successfully (or unsuccessfully), and presents lessons learned. The paper concludes with a summary and recommendations for best practices for Project Risk Management and mitigation that can be used by: Owners; Design Engineers; and Construction Managers, in planning, design, pre-construction and construction phases of dam related projects.

By Juhyung Lee

Numerical analyses were performed to analyze the behavior of two different type of suction piles (mono type and group type) under various soil layer conditions (uniform silty clay layer, uniform silty sand layer, and two-layer deposit consisting of clay and sand layers) and lateral loading locations (top, middle, and bottom of the suction pile). According to the results, mono suction pile shows maximum resistance when load is applied on its middle, regardless of the soil layer conditions, while group suction piles varies significantly according to the allowance on head rotation. When head rotation is allowed, the behavior of group type piles become similar to the behavior of mono suction pile. Whereas, when rotation is prevented, resistance is maximized when load is applied on the top head. Moreover, group suction piles show higher efficiency regardless of the ground condition and geological stratum. For further advances, concrete block on the top of group suction piles are suggested as an effective alternative method to prevent partial rotation and maximize ground resistance for group suction piles.

By Andhra Pradesh, Nagarajkumar B. V

As a part of Mumbai City Mega Drinking Water Project at Amar Mahal Tunnel-1 Ghatkopar East Mumbai, drinking water tunnels were proposed by MCGM from Amar Mahal to Trombay reservoirs, Amar Mahal to Wadala and further up to Parel. The pipeline has to be underground and laid at a depth of 5.5m. The initial proposal was to provide sheet piling to enable the safe excavation and installation of underground pipeline. However, installation of sheetpiles was practically not feasible due to the existing soil strata for driving the sheet piles. Hence, it was proposed to install micropiles instead of sheet piles. In this paper we discuss about the purpose, basic design, detailed design approaches and actual work implementation of micro pile with temporary struts for shoring protection works in this project.

Sep 1, 2022

By Terence P. Holman

Instrumented load testing of high capacity micropiles, followed by detailed analysis and numerical modeling, provided an opportunity for real foundation performance to be incorporated into the design of a complex urban high-rise structure. This paper discusses a design-based load testing program and subsequent analysis for micropiles incorporated into a piled raft foundation beneath a portion of a high-rise residential structure in Brooklyn, New York. Preliminary numerical analysis, performed using the commercial finite element package PLAXIS 3D Foundation, indicated that soil stiffening and transferring heavy core loads to greater depths was required to minimize the total and differential settlements. High capacity micropiles were modeled below the tower core mat to create a piled raft effect, reducing the settlements to acceptable levels. Final design of the foundation and micropiles, and final numerical analysis of the proposed foundation system required an instrumented load testing program to provide the Owner and design team with a level of comfort. The instrumented load test provided data on the evolution of load transfer, including the mobilization of significant tip resistance, frequently ignored in design, and micropile axial stiffness. Final numerical analysis of the foundation system involved refining the PLAXIS model based on the micropile behavior and load transfer mechanism observed during the load test program. The authors believe that the combination of design-based load testing and numerical analysis in this project yielded a more refined foundation system with realistic expectations of performance.

Jan 1, 2007

By Alexander Scheuermann, Martin D. Larisch, David J. Williams

"Drilled displacement piles (DDP) have been used around the world for decades as foundation elements for structures and embankments. Typically the pile toes are designed to penetrate into stiff or dense soil formations to achieve sufficient base resistance. Recent research at The University of Queensland in Brisbane, Australia has discovered that the in situ stress conditions in stiff to hard clays is directly related to pile installation rates, which in turn are a function of the piling rig capacity and ground conditions. With adequate and constant pile penetration rates in situ stress conditions in the stiff to hard clay are increased by about 40%, resulting in significantly higher pile capacities. If pile penetration rates are too slow the in situ stress conditions are reduced considerably by remoulding and shearing of the clay, potentially causing reduced pile capacities. The paper presents the results of full-scale test piles at a stiff to hard clay site installed using different full-scale piling equipment.INTRODUCTIONDrilled displacement piling (DDP) is a piling technique in which a hollow stem, fitted with a purpose built displacement tool at the bottom, is drilled into the ground. Dissimilar to non-displacement piles, like Continuous Flight Auger (CFA) piles or conventional rotary bored piles drilled with kelly bars, the soil is not excavated during the DDP penetration process, but is displaced laterally and to a lesser extent vertically. The cavity created by the drilling tool is filled with highly workable concrete during the extraction process. The DDP technique is very economical providing high production rates and creating only marginal drill spoil, which has led to its increased global usage during the last decade. The typical DDP installation process is described in Figure 1."

Jan 1, 1900

By J. P. Powers

Methods for dewatering and the control of ground water for construction and mining are discussed, including open pumping; predrainage with deep wells, wellpoints or other systems; cutoff or exclusion of water by steel sheet piling, slurry concrete walls and slurry trenching, grouting, ground freezing, compressed air, slurry shields and earth pressure balance shields. Criteria are given for the selection among the methods for a given project. Unwanted side effects of dewatering are listed, with procedures for evaluating and avoiding them, by cutoff or artificial recharge.

Jan 1, 2010

By Silvana B. Foá

Results from full-scale loading tests showed the use of the dynamic increasing energy test (DIET) to verify the capacity of deep foundations. This method allows the measurement of dynamic resistance - displacement curve and the prediction of the static resistance -displacement curve of the pile-soil system. The comparison between the use of DIET versus the static load test is also considered herein. This work was divided in two different phases, the first accomplished in Salvador (Bahia) and the second in Brasilia (Federal District), both in Brazil. The first phase consisted of field loading tests carried out on piles comprised by an approximate 10 to 12 meters thick deposit of fine saturated sand, overlying a stiff clay layer, which is found in certain areas of the Brazilian Northeast. Two metallic (rail track) piles were field loaded in this site. One of them was dynamically tested and the other was statically tested. The second site belongs to the Post Graduate Program of the University of Brasilia. It is comprised by an approximate 8 to 14 meter think deposit of porous clay, overlying a hard strata of saprolitic state. In this site a unique precast driven centrifuged pile was tested. The DIET procedure has demonstrated to be a tool of fast execution and low cost (if compared to static load test). It is a promising procedure to evaluate the behavior of pile-soil system.

Jan 1, 2002

By Lisheng Shao

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

Jan 1, 2010

By Serge Borel

An efficient design method is proposed for "piled-footing" and "piled-raft" foundation under lateral loads. It combines the methods used for the displacement design of shallow and deep foundations and takes into account the interactions between the piles and the cap or raft. This method has been applied to previous full-scale tests carried out in the United States. Two groups of six instrumented driven piles were laterally loaded several times: first with the concrete pile cap in direct contact with the soil, and then, after a thin layer of soil had been removed beneath the cap. The proposed method models well the real behavior of piled-raft foundations. It highlights the positive effect of the cap in contact with the soil, which reduces significantly the displacements and the maximum pile bending moments. These are divided by two for the analyzed case histories.

Jan 1, 2002

By W. Morgan NeSmith

"The DFI ACIP Pile Committee, in conjunction with the Florida DOT, completed an ACIP Pile installation monitoring and performance test program in late 2016 to advance the inclusion of ACIP piles in future specifications for bridges by state agencies. Piles of different diameters were installed for compression, tension and lateral testing, and one pile was extracted for visual inspection. This paper presents the pile installation, non-destructive testing and load test results of the program.INTRODUCTION The Deep Foundations Institute (DFI) Augered Cast-In-Place (ACIP) Pile Committee performed a ACIP pile installation and test program in the fall of 2016 to demonstrate a fully monitored installation of 18-in and 24-in diameter ACIP piles. The program included automated and manual installation monitoring, Thermal Integrity Profiling, compression, tension and lateral load testing (including monitoring of strain gages embedded along the compression pile shaft), and post-testing extraction of an installed pile for visual inspection.PROJECT DETAILS AND FIELD EXPLORATION A general program location map along with an aerial view of the property in Okahumpka FL is shown in Figure 1. Two Cone Penetration Tests (CPT) were performed at initial reaction pile locations R-6 and R-8 (Figures 2 and 3) The results from CPT R-6 indicated very loose soil conditions at depths below 55-ft, indicating potential relic sinkhole conditions. The test layout was subsequently rotated and moved south of CPT R-8.TEST PILE INSTALLATION DETAILS Seven piles were installed to either 40-ft or 60-ft below grade. Thermal Integrity Profile (TIP) wires were installed in all piles but varied to include one wire each attached to a steel center bar or one wire attached to the steel center bar AND four additional wires (each) attached the steel reinforcing cage installed in these piles. Additionally, the 24-in lateral and compression piles had four steel or PVC casings installed next to the TIP wires for testing by thermal probe and/or wire inserted into the casing."

Jan 1, 2017

By H. R. Masoumi

This paper presents a numerical model for the prediction of free field vibrations due to vibratory and impact driving. As the focus is on the response in the far field, where deformations are relatively small, a linear elastic constitutive behavior is assumed for the soil. The free field vibrations are calculated by means of a coupled FE-BE model using a subdomain formulation, proposed by Aubry and Clouteau (1992). The model is validated by means of the results of Kaynia and Kausel (1991) for the impedance of a single pile. First, the case of vibratory pile driving is considered, where the contributions of different types of waves are investigated for several penetration depths. The results show that in the near field, the response of the soil is dominated by a vertically polarized shear wave, whereas in the far field, Rayleigh waves dominate the ground vibration and body waves have been importantly attenuated. Second, the case of impact pile driving is considered. A linear wave equation model is used to estimate the impact force during the driving process. Furthermore, it is investigated how the soil stratification influences the ground vibration considering the case of a soft layer on a stiffer half space. The results show that when the penetration depth is smaller than the layer thickness, the layered medium has a small influence. However, when the penetration depth is larger than the layer thickness, these effects become more significant. Finally, the computed ground vibrations are compared with experimental data reported in the literature.

Jan 1, 2006