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By Chetan D. Savani, Mike K. Muchard

The necessity to evaluate undocumented foundation lengths is essential in assessing the useable life, need for scour protection, retrofitting, or full reuse of existing bridge foundations. For this purpose, Parallel Seismic Testing (PST) has the best accuracy and is applicable to the widest range of foundation configurations used in bridge construction of any test method. Although not limited to bridges, PST case studies are presented involving two bridges. To preface the case study discussions, an overview of the PST method is given along with its results and analysis thereof. In one of the cases, we were afforded the rare opportunity to see the existing piles being extracted long after the PST testing program was completed. The resulting Class A prediction reaffirms the accuracy of the method. Versatility of the PST method is also exemplified in the two cases presented, where unique situations from complex foundation systems were overcome by analysis to provide successful results.

By Rudolph P. Frizzi

The current trend of increasing augered cast-in-place (ACIP) pile diameter, length, and load carrying capacities demonstrates improvements in installation equipment, increased acceptance, and that quality control is being successfully implemented by the parties involved in the ACIP pile construction process. Quality control is essential for ACEP piles since 24- to 36-in-dia (610-to 915-mm-dia) piles are currently being constructed to sustain design compressive loads of 800 to 900 kips (3555 to 4000 kN). This paper presents a summary of ACIP pile quality control procedures and methods beginning in the design and bid process, through ACIP pile installation, to post-construction. The results of a recent survey of contractors, engineers, equipment suppliers, and researchers routinely involved with ACIP piles in the United States, Europe, and the Middle East are included to address current trends in ACIP piles and quality control.

Jan 1, 2001

By Dongwook Kim

Recently, load and resistance factor design (LRFD) is gradually being adopted internationally in geotechnical design due to the advantages of LRFD over the existing allowable stress design (ASD). LRFD is a more advanced design method compared to the ASD because resistance factor is calibrated based on the reliability analysis for a given target reliability index. Target reliability index changes with the importance of the structure. Typically, target reliability index of offshore foundation is less than those of onshore. The widely-used Imperial College Pile (ICP) design method is used for the calculation of pullout capacity of driven piles. The uncertainties regarding pullout capacities of driven piles are assessed using the statistical data reported in the literature. The first-order reliability method (FORM) is used to calibrate resistance factors for the pullout ultimate limit states of the driven piles for three different levels (2.5, 3.0, and 3.5) of target reliability index. The load factors used in this paper are the ones proposed in the AASHTO LRFD bridge design specifications.

Jan 1, 2010

By James R. Gingery, Byron Foster, Bret Lingwall

While microzonation and setbacks are the typical mitigation for structures exposed to surface fault rupture hazards, lifelines and lifeline facilities are not easily relocated to avoid faulting. In these cases, other remedial measures including ground improvement may be warranted. Deep soil mixing ground improvement was used in this case to mitigate surface fault rupture and liquefaction hazards for a pump station at a wastewater treatment plant with wet wells up to 36-feet (11-m) deep. Paleoseismic field investigations were performed to characterize the site, then deterministic and probabilistic fault rupture displacement estimates were made and used to develop design scenarios. The fault rupture mitigation design consisted of a solid block of DSM encompassing and protecting the pump station and its wet wells. Three dimensional soil-structure interaction numerical modeling of the fault rupture scenarios was performed as part of the design. The analyses showed the fault rupture displacements could be diverted by the DSM and that satisfactory structure performance could be achieved. The design required construction of a large 100 percent replacement ratio block of DSM with a compressive strength of 500 psi. Aspects of construction of this DSM block are discussed.

Sep 8, 2021

By C. Michael Morgano

Static tests are costly and time consuming, so they are not always the best answer [ ]

Jan 1, 2005

Jan 1, 1998

Jan 1, 1993

By Alexandra Weidle, Seffen Leppla, Rolf Katzenbach, Matthias Seip

"A lot of different deep mixing systems have been developed in the last decades for a wide spectrum of applications, e.g. retaining and foundations systems, soil improvement, sealing of toxic substances or dyke strengthening. The paper will deal with special aspects of constructions with deep mixing systems for infrastructures like soil improvement for cyclic loadings and underpinnings in difficult soil conditions by presenting cases from engineering practice.1. DEEP DRY SOIL MIXING FOR SOIL IMPROVEMENT OF RAILWAY TRACKS IN VERY SOFT SOILS1.1 IntroductionRailway tracks are set into vibrations by train passing. In very soft soil this leads to long-term deformations which lead to speed limits, temporary closings and big maintenance efforts. The energy of the dynamic loading is transmitted into the soil by compression and shear waves and at the surface by rayleigh waves (Wood 1968). The expansion of the waves are influenced by•,thickness of the soft soil layer•,density of the soft soil layer•,stiffness of the soft soil layer•,saturation of the soft soil layer•,frequency of the dynamic loadingThe frequency of the dynamic loading depends on the train velocity and the distance of the wheels and wheel sets. If the frequency of the dynamic loading is in the range of the natural frequency of the soft soil layer the vibrations increase extremely (Lieberenz et al. 2003). As a result the long-term deformations will increase as well.To avoid these long-term deformations and the resulting operation restrictions and maintenance efforts an adequate soil improvement is necessary. For the optimization of the soil improvement field tests have been carried out.1.2 Experimental field testsThe field tests have been carried out at a 300 m long test track with five different setups, each 30 m long:•,test track TS 0: no soil improvement•,test track TS 1: soil improvement with single lime-cement-columns 5.9 m deep (Figure 1a)•,test track TS 2: soil improvement with single lime-cement-columns 5.9 m and 10.4 m deep (Figure 1b)"

Jan 1, 2015

By Monique Nykamp

"INTRODUCTIONTerminal 46 is located just south of downtown Seattle, and is one of the Port of Seattle’s busiest container terminals. The Terminal 46 Redevelopment Project was undertaken to replace the existing 15-m-wide (50 ft) cranes along the apron with 30-m-wide (100 ft) cranes, which can unload larger, post- Panamax ships. The project included upgrading the existing waterside crane rail with new piles and constructing a new land-side rail behind the sheetpile bulkhead. The new piles had to be installed adjacent to the existing apron without causing damage, which was a signifi cant geotechnical challenge due to the soft soil conditions at the site. An instrumentation program performed during the test pile program evaluated this challenge and allowed for the development of specifi c production pile installation procedures that had the least possible effect on construction costs and schedule. SITE HISTORYThe site lies along the west side of Elliott Bay, north of the mouth of the Duwamish Waterway. Prior to development, this area was part of the tide fl ats where the Duwamish River drained into Elliott Bay. Prior to 1970, there were several existing timber piers and structures in the area. In the 1970s, the Port of Seattle constructed a 900-m-long (3,000 ft), 30- m-wide (100 ft) apron to support fi ve, 15-m-wide (50 ft) container cranes. The contained backland area was then fi lled with dredged spoils (sand and silt with organics) and the upper 5 to 20 m (16 to 65 ft) backfi lled with sand and gravel.The existing apron was constructed using 0.4 m (16 in) octagonal prestressed concrete piles to support the precast concrete deck and crane rails. The pile-supported bents were spaced at 6.1 m (20 ft), center-to-center, along the longitudinal direction. Pile lengths typically varied from about 20 to 40 m (65 to 130 ft) with 15 to 26 m penetration below mudline (50 to 85 ft penetration). The slope below the apron was constructed at about 1.75 horizontal to 1 vertical to allow for suffi cient water depth for cargo ships. In most areas, a riprap buttress was placed at the toe of the slope. A typical cross section of the apron is shown on Figure 2.Several stability, settlement and pile driving issues arose during the original construction of T-46 (Pita, 1983). Reportedly, movement of the submarine slope occurred during pile driving, resulting in settlement behind the bulkhead. Pile driving reportedly caused settlement of adjacent piles. In addition, some piles were “running” (dropping quickly under one hammer blow) during installation."

Jan 1, 2007

By Monique Nykamp

"INTRODUCTIONTerminal 46 is located just south of downtown Seattle, and is one of the Port of Seattle’s busiest container terminals. The Terminal 46 Redevelopment Project was undertaken to replace the existing 15-m-wide (50 ft) cranes along the apron with 30-m-wide (100 ft) cranes, which can unload larger, post- Panamax ships. The project included upgrading the existing waterside crane rail with new piles and constructing a new land-side rail behind the sheetpile bulkhead. The new piles had to be installed adjacent to the existing apron without causing damage, which was a signifi cant geotechnical challenge due to the soft soil conditions at the site. An instrumentation program performed during the test pile program evaluated this challenge and allowed for the development of specifi c production pile installation procedures that had the least possible effect on construction costs and schedule.SITE HISTORYThe site lies along the west side of Elliott Bay, north of the mouth of the Duwamish Waterway. Prior to development, this area was part of the tide fl ats where the Duwamish River drained into Elliott Bay. Prior to 1970, there were several existing timber piers and structures in the area. In the 1970s, the Port of Seattle constructed a 900-m-long (3,000 ft), 30- m-wide (100 ft) apron to support fi ve, 15-m-wide (50 ft) container cranes. The contained backland area was then fi lled with dredged spoils (sand and silt with organics) and the upper 5 to 20 m (16 to 65 ft) backfi lled with sand and gravel.The existing apron was constructed using 0.4 m (16 in) octagonal prestressed concrete piles to support the precast concrete deck and crane rails. The pile-supported bents were spaced at 6.1 m (20 ft), center-to-center, along the longitudinal direction. Pile lengths typically varied from about 20 to 40 m (65 to 130 ft) with 15 to 26 m penetration below mudline (50 to 85 ft penetration). The slope below the apron was constructed at about 1.75 horizontal to 1 vertical to allow for suffi cient water depth for cargo ships. In most areas, a riprap buttress was placed at the toe of the slope. A typical cross section of the apron is shown on Figure 2.Several stability, settlement and pile driving issues arose during the original construction of T-46 (Pita, 1983). Reportedly, movement of the submarine slope occurred during pile driving, resulting in settlement behind the bulkhead. Pile driving reportedly caused settlement of adjacent piles. In addition, some piles were “running” (dropping quickly under one hammer blow) during installation."

Jan 1, 2007

By Alexi J. Neill

"This presentation will showcase two challenging projects with deep excavation support systems in the Atlanta area where state-of-the-art instrumentation and monitoring systems were used to manage risk by confirming design performance requirements / calculations during construction. The instrumentation and monitoring system successfully reduced risk by recording real-time data on a project website while simultaneously sending email alarms to key site personnel when data exceeded pre-determined alarm thresholds. The monitoring data revealed unexpected performance at an early enough stage so that contingency plans could be engaged and remedial efforts devised in order to limit the consequences. Finite element analysis was used to model deformations, analyze the unexpected performance, and prepare theremedial design.INTRODUCTIONConstruction in densely populated urban areas is becoming more common in order to keep up with the increasing infrastructure demands of our growing population. America’s big cities continue to outpace the overall nation in population growth. The city of Atlanta, the nation’s ninth largest city based on metropolitan population, is a prime example of this. The population has grown at a rate of 6.6% between 2010 and 2013, nearly triple the overall growth rate of the United States during the same period (SustainAtlanta, 2015).As a result of increasing infrastructure demands in Atlanta, developers are now constructing larger buildings on smaller properties. In addition, developers are attempting to maximize space on their selected properties, often by designing underground parking garages to accommodate as many cars as possible on these compact sites. In some cases the selected sites are adjacent to buildings, utilities, and other existing structures. The risk associated with construction increases during underground work that requires a support of excavation system, particularly on confined sites adjacent to existing structures. There is a risk posed to people, property, and the environment that the project team should monitor when constructing in these conditions."

Jan 1, 2016

By Kishore Kumar B., Eswaran Prasad C R, Srini Naik B., Ramakrishna Raju N

The authors through this paper intend to introduce the non-vibro technique of ground improvement by stone column, being used for the first time in India under the Western Dedicated freight Corridor in Mumbai area. New 2x25 KV double line dedicated freight corridor tracks, capable of carrying 32.5-ton axle load are proposed to be built on this stretch. Non-Vibro Displacement Stone Columns of 900 mm diameter were installed to improve the safe bearing capacity of the soft ground to take the loading of Dedicated Freight Corridor Railway embankment. Vertical footing load tests on single and three column groups were conducted to assess the improvement in the sub-surface condition after installation of stone columns. This paper describes load tests conducted on stone columns and analysis of the obtained results. The observed load settlement behaviour of the improved ground has also been presented. Behaviour of single and group of stone columns have been compared and criteria adopted for arriving at desired factor of safety based on the settlement observed, has also been discussed.

Nov 1, 2022

By Chris L. Powell, Russell J. Denny

"The remotely located Cockatoo Island iron ore mine off the Kimberley coast in the northwest of Western Australia has been in operation since 1951. The mine was recently expanded up to about 50 m (165 ft) below sea level using staged construction to create a rockfill seawall around the open cut mining operation. Late in 2013, to allow expansion of subsea iron ore mining operations, Wagstaff Piling was engaged to install a seepage barrier through the rockfill seawall and into the underlying seabed sediments.Earlier stages of seawall construction had used a variety of different construction techniques with varied success, and the history of subsea mining on the island had been plagued with failures, including failures in the slope of the seawall itself, hanging wall failure underneath and inside the seawall, and footwall failures as the ore was mined leaving the rock face inclined at 55 degrees, parallel to the bedding. The current expansion, known as the Stage 4 expansion, was more tightly constrained by the pit geometry and available materials than previous seawall expansions that adopted clay core and sheet pile seepage barrier solutions. In Stage 4, an innovative seepage barrier solution using a grout curtain was selected to provide the necessary cutoff to allow access to high-grade ore, while protecting the mine from inundation by the sea.Seawall ConceptThe open cut subsea mining operation consisted of a 3 km (1.9 mi) long narrow pit along the south side of Cockatoo Island that extended to depths of about 50 m (165 ft) below sea level, and were exposed to the open sea on the south side of the pit. Massive tidal variations of more than 10.5 m (34.5 ft) required a seawall founded on the seabed, extending upwards to RL+13, to safely protect the pit from the high tide level rising to above RL+10."

Jan 1, 2017

By Chris L. Powell, Russell J. Denny

"The remotely located Cockatoo Island iron ore mine off the Kimberley coast in the northwest of Western Australia has been in operation since 1951. The mine was recently expanded up to about 50 m (165 ft) below sea level using staged construction to create a rockfill seawall around the open cut mining operation. Late in 2013, to allow expansion of subsea iron ore mining operations, Wagstaff Piling was engaged to install a seepage barrier through the rockfill seawall and into the underlying seabed sediments.Earlier stages of seawall construction had used a variety of different construction techniques with varied success, and the history of subsea mining on the island had been plagued with failures, including failures in the slope of the seawall itself, hanging wall failure underneath and inside the seawall, and footwall failures as the ore was mined leaving the rock face inclined at 55 degrees, parallel to the bedding. The current expansion, known as the Stage 4 expansion, was more tightly constrained by the pit geometry and available materials than previous seawall expansions that adopted clay core and sheet pile seepage barrier solutions. In Stage 4, an innovative seepage barrier solution using a grout curtain was selected to provide the necessary cutoff to allow access to highgrade ore, while protecting the mine from inundation by the sea.Seawall ConceptThe open cut subsea mining operation consisted of a 3 km (1.9 mi) long narrow pit along the south side of Cockatoo Island that extended to depths of about 50 m (165 ft) below sea level, and were exposed to the open sea on the south side of the pit. Massive tidal variations of more than 10.5 m (34.5 ft) required a seawall founded on the seabed, extending upwards to RL+13, to safely protect the pit from the high tide level rising to above RL+10."

Jan 1, 2017

By Stefano Pirrello

"Sydney’s booming real estate market has pushed property developers to invest in historically “no-go” areas, which were previously too expensive to develop. These areas are usually near rivers where the sites are underlain by deep alluvial and estuarine sediments. In these ground conditions conventional bored pile techniques are often not competitive. Contiguous Flight Auger (CFA) and Drilled Displacement Piles (DD) techniques are on the other hand suitable for these ground conditions. This paper deals with the design and construction challenges encountered with these piling techniques for a series of high-rise towers in Sydney’s West. The advantages of DD over CFA piles such as reduced overall spoil with substantial cost savings and achievable rock sockets in medium strength bedrock are discussed. Design validation through interpretation of real-time data from the piling rigs’ on-board computer data, and low and high strain pile dynamic testing (PDA) is discussed. Testing data is presented as CAPWAP (Case Pile Wave Analysis Program) analyses for different concrete grades.INTRODUCTIONThe booming real estate market in Sydney has pushed property developers in investing in historically “no-go” areas, which were previously too expensive to develop. These areas are usually near rivers where the sites are underlain by deep alluvial and estuarine sediments. In these ground conditions conventional bored pile techniques are often not competitive. Contiguous Flight Auger (CFA) and Drilled Displacement (DD) Pile techniques are on the other hand suitable for these ground conditions and were utilised using concrete injection methods. This paper deals with the design and construction challenges encountered with these piling techniques for a series of high-rise towers in Sydney’s West.GEOLOGY & GEOTECHNICAL CHARACTERIZATION OF THE SITEThe Sydney 1:100 000 Geological Series Sheet shows that the site is underlain by man-placed filling and alluvial/estuarine sediment. The sediment comprises silty to peaty sand, silt and clay. Shell layers are also expected to be present within the soil profile. The Prospect/Parramatta River 1:2500 Acid Sulphate Soil Risk Map shows the site as ‘Disturbed Terrain’ in which soil investigations are required to assess acid sulphate soil potential. Several Cone Penetration Tests and Boreholes were carried out during the geotechnical investigation. All boreholes were extended to bedrock and NMLC-sized diamond core drilling was used to obtain 50mm continuous core of the rock, enabling unconfined compression strength testing to be carried out on selected samples. A summary of the ground conditions encountered on this site and inferred from the CPTs can be described as follows:"

Jan 1, 1900

By William (Bill) H. Walton

"I arrived in Chicago in 1993 with Dr. Ralph Peck’s University of Illinois bulletin titled Engineering Properties of Chicago Subsoils (Bulletin 429), which he published in 1954 with William Reed. Being an outsider, I wanted to learn from Chicago geotechnical practice leaders that included Clyde Baker, Jr., John Gnaedinger, Charles Pfingsten, Dr. Safdar Gill, Robert Lukas and Dr. Jorj Osterberg, who have influenced foundation designs for the structures that make up the contemporary Chicago skyline. One of my immediate goals was to get the Illinois Structural Engineering license to be on par with the likes of Eli Cohen, Mike Tylk, Stan Korista, Bob Halverson, Joe Burns, Ron Johnson, Bill Baker, Bob Sinn, Chuck Anderson and Dave Eckmann, who have led their structural firms in the design of the skeletal core and frames of many of Chicago’s iconic buildings (and for many other buildings around the world). From my time with GEI Consultants (GEI), then on with STS Consultants (STS, and now AECOM), and now back with GEI, I have had the opportunity to analyze and design foundations and, with the help of many skilled foundations and building constructors, to verify that predicted foundation performance matches actual movement data. The theme of Chicago’s foundation design practice is to assume and verify. In 1948, Peck published the History of Building Foundations in Chicago (Bulletin 373) that was updated in 1998 by Baker, Pfingsten and Gnaedinger, who meticulously documented hundreds of Chicago’s foundations, and have shown the value of advanced analyses and testing to advance the deep foundation design practice that includes a variety of high-capacity driven and drilled deep foundations. Mehmet Uyanik, Peck and Baker have made Chicago’s subsurface into a full-scale foundation test laboratory. They confirmed soil mechanics principles like Terzaghi’s 1-D consolidation theory when early foundations bearing on sand-clay crust over soft to medium silty clays (e.g., Auditorium, Masonic Temple, Monadnock Block and Old Board of Trade buildings) took 40 to 60 years to consolidate clay 1 to 2 ft (0.3 to 0.6 m). They also confirmed proven increases in bearing pressures based on measured performance of deep foundations bearing on the glacially derived hardpan clay till and in solid dolomite that underlies Chicago."

Jan 1, 2017

By Carlandrea Albonico, Salvatore Miranda

After a brief introduction of the whole Project, the paper describes two special geotechnical engineering solutions provided within the scope of the Galataport Project, in Istanbul, Turkey. The first refers to the new quay of Salıpazarı, which is a combination of retaining structure and ground improvement, formed by a combiwall, a reinforced concrete diaphragm wall and a soil improvement by deep soil mixing (Turbojet). The second, refers to the soil improvement works executed underneath three existing buildings. Single-fluid jet grouting columns had the scope of improving the mechanical properties of the bearing soil and reducing the associated risk of liquefaction. A set of underpinning micropiles was installed in order to allow the excavation of a partial basement inside two of these three buildings. All activities were conducted from inside the existing buildings, with reduced headroom. The paper highlights the importance of employing cutting-edge technologies within the foundation engineering field and state-of-the-art electronic control devices, in parallel with the essential human expertise, in order to obtain the desired results in this high-profile Project.

Nov 1, 2022

By Nick O’Riordan, Kaitlyn L. Fleming, Michael Riemer, Youssef M. A. Hashash, Stephen McLandrich, Mohamad Jammoul, Pierre Gouvin, Andrew Yeskoo

"To accommodate urbanization, cities are developing more underground space as a means to house public transportation systems and other entities. Underground developments often require construction of deep excavations in an environment dense with infrastructure. The success of such a project is related to the amount of impact imposed on adjacent structures and economic activity; impact should be limited to insignificant amounts in order to mitigate damage and disruption. Thus, large-scale urban construction projects require extensive monitoring of ground movements and installed support performance to facilitate informed decisions for adjustment of construction activities and support design when necessary.In downtown San Francisco, a unique large-scale excavation in saturated soft soils was constructed for the Transbay Transit Center (TTC). Construction of the excavation began in April 2012 and was completed almost two years later in February 2014. To monitor ground and structure response to construction, the project team used an extensive instrumentation network that included automatic inclinometers, piezometers, strain gages and total stations paired with survey markers. Innovative imaging techniques developed a record of construction in order to relate measured deformations to construction activity.Transbay Transit CenterThe Transbay Transit Center (TTC) is being constructed as a modern day transportation hub in downtown San Francisco to replace the former Transbay Terminal. The project is located in the South of Market area, less than half a mile from the San Francisco Bay. The final center will connect eight counties in the Bay Area through 11 different transportation systems, some of which will be housed in the TTC including Caltrain, Golden Gate Transit and California High Speed Rail. The aboveground structure will consist of two levels for retail and a third level with a bus terminal beneath a rooftop garden. There will be two subgrade levels to serve as a lower concourse and the train platforms. This structure required construction of a deep excavation closely surrounded by buildings and roads in an area thriving with economic activity."

Jan 1, 2015

By J. E. De Waele, J. J. Lee, M. J. Mulheron, Luke R. Deamer

There is increasing demand for geotechnical contractors to commit to carbon reduction, net zero or science based targets. A lot of focus has therefore been placed on using low carbon materials and low emission rigs. However, whilst these are ways to help reduce carbon, there is a need to look beyond just substituting materials and fuels to meet net zero. Using the IEMA carbon hierarchy, there is a need to first look at eliminating and reducing emissions, before considering substitute materials. For example, in geotechnical designs, this may mean considering using ground improvement or reducing the number of piles, before considering using low carbon cements. Equally, for remaining emissions, this hierarchy means considering carbon negative products to offset emissions, such as ground source heat pumps. This hierarchy can also be applied throughout geotechnical contractor organisations. For example, considering video conferencing for meetings, before considering public transport or using an electric vehicle. This article explores the carbon hierarchy and how it can be applied to all areas of a geotechnical contractor’s business. Only through embedding this hierarchy across the business can geotechnical contractors achieve the step change required to meet net zero.

May 1, 2022

By Scott Webster

Dynamic pile Monitoring Services (DMS) have been used for testing of offshore piles for several decades. However, most of this testing was to measure hammer performance and pile stresses rather than pile capacity or soil resistance. As the need for more economical solutions for foundation support increases, the use of DMS has provided a better means of evaluating in-place pile capacity for offshore structures, and therefore a method of determining pile acceptance. The authors have been involved in several offshore projects where DMS has been the primary source of data for acceptance of the driven pile foundations. The use of DMS for evaluation of offshore foundations requires considerations quite different from land applications and these considerations are often necessary for the careful and thorough analysis of the collected data in nearly real time for determination of pile acceptance. Case Method capacity estimates are often of little use due to the non-uniform cross sections of the foundation piles and their deep penetrations. Therefore, capacity assessments should be made using CAPWAP which is a signal matching program whose utility and reliability has been proven on thousands of projects every year, both on land and offshore. Depending upon the soil conditions at a given location, capacity assessment after soil setup effects may be necessary. In addition, tension capacity is often critical when pile refusal occurs significantly before the design pile penetration depth. Evaluation of uplift capacity can be accomplished by a CAPWAP analysis, which results in a total capacity prediction and its shaft resistance component. The use of hydraulic hammers for driving of these piles also adds the requirement of controlling hammer energy such that over-stressing of the pile is avoided. The calculation of non-axial stresses such as bending or eccentric stresses may also be involved in order to prevent pile damage.

Jan 1, 2010