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By P. Kiruthika, A. Murali Krishna

Soil liquefaction is a dangerous phenomenon that involves huge damages during strong earthquake ground motion event. Stone columns (SCs) are widely used as liquefaction mitigation element which is expected to perform the improvements against liquefaction hazard by densifying, increasing the stiffness and rapid dissipation of excess pore water pressure in the surrounding soil. Although in the recent times few studies on the behaviour of stone columns in the seismic zone has evolved, the performance of SCs in the multi-layered soils is not extensively examined. This paper presents the numerical investigations on the performance of SCs installed in the multi-layered soils as a liquefaction mitigation measure against the seismic loading. The acceleration time histories, Excess Porewater Pressure (EPP), vertical displacement and stress ratio evaluated along different depths using PLAXIS 2D. With the installation of stone column there is a considerable reduction in the acceleration amplitude, which in turn reduces the EPP and vertical displacement at different locations and the amplitude of reduction depends on the soil stiffness levels at the depth.

Sep 1, 2022

By Aditya Ayithi, William G. Ryan, Dean Herbst

"For rock socketed drilled shafts, it is a common practice not to include the frictional resistance of overburden soils into the nominal capacity estimation. The primary reason often being cited is “overburden soils resistance is negligible compared to that of rock socket resistance.” However, in certain geological conditions, where the rock layer is located at greater depths, friction resistance from overburden layers can be significant. In addition, at such great depths, shaft drilling becomes very complicated and expensive. In these situations, considering the resistance of the overburden layers can be an economic alternative.This paper presents a case study of an Osterberg cell (O-cell) load test conducted on a 161.8 feet long and 78-inch diameter instrumented test shaft. Based on initial designs, a 72-inch diameter rock socket of lengths 23 and 26 feet was required to provide a LRFD factored friction resistance of 3,200 kips. The load test results revealed that the material in the 72-inch diameter socket does not represent a true rock. However, the test results also proved that the factored friction resistance of overburden layers is greater than the required design resistance. Based on the load test results, it was decided to allow the overburden soils frictional resistance to be considered in the shaft design, resulting in significant economic savings.INTRODUCTIONRock socketed drill shaft design guidelines of various State Department of Transportation (DOTs) agencies allow friction and/or end bearing resistance of only the rock socket portion into the design capacity estimation. It is typical to neglect the frictional resistance of overburden soils. However, in certain geological conditions where the rock layer is at greater depths, friction resistance of the overburden soils can be significant. In this case the friction resistance of overburden soils was verified via the specified instrumented O-cell test program and then used as part of the design capacity.PROJECT DESCRIPTIONAs part of I-29 improvement project, Iowa Department of Transportation (Iowa DOT) planned to replace the dual four lane bridges that cross the Floyd River in Sioux City, Iowa with dual six lane bridges (Fig. 1). Expected benefits from this improvement include improved safety, traffic operations and roadway infrastructure conditions.BRIDGE SUBSTRUCTUREThe project consists of two individual bridges; a new south bound bridge and a new north bound bridge. The south bound bridge is 646-ft long and the north bound bridge is 644-ft long. Both are six-span, pretensioned and pre-stressed concrete beam bridges of varying width. Bridge foundations were designed such that the abutments of both bridges will be supported on driven steel piles and the bridge piers will be on drilled shaft foundations."

Jan 1, 2016

By Jerold Bishop

The application of the ?electro-hydrodynamic effect? (EHDE) to civil engineering has been made in the construction of drilled piles. Equipment for the commercial application of this process was developed in Russia in the late 1980's. The process is approved for general use by the Russian Federation building code and numerous projects have been successfully completed with this technique. EHDE is a process by which a moderately powerful shockwave is released in the bottom of a drill hole filled wet concrete slurry. The energy is carried outward through the fluid with minimal loss because it is an incompressible medium. Repetitive discharges provides a series of energy pulses which will compact the soil along the pile shaft and at base of the pile. The process is analogous to repeated applications of low energy blast densification or to dynamic compaction. In general, the process is not depth dependent. Repeated application of this treatment in a drilled pile hole can increase soil density at the base and along the shaft of the pile, as desired. The overall result is that the geotechnical capacity can be improved significantly. Test results documenting improvements are presented and other applications considered.

Jan 1, 2007

By Mark D. Fuhriman, Parham Khoshkbari, Robert Fosse

Drilled displacement piles are becoming an increasingly common deep foundation choice for their relatively simple installation methods, applicability to a wide range of subsurface conditions, and versatility. The installation method includes drilling and displacement of the soil followed by delivery of fluid cement grout under pressure, and placement of steel reinforcing to complete the pile. Because the installation method uses blind processes that do not permit direct observation of the pile, it is desirable to employ redundant testing tools to complement good construction techniques and inspection practices to ensure integrity of the piles. This paper examines the use of a range of integrity testing tools used for pile installations at a major office campus development. Because the integrity of a drilled displacement pile and its performance depend to a large extent on the skill and experience of the installation crew, the paper explores how use of multiple practical tools, including automated monitoring tools on the pile installation equipment, thermal integrity profiling, and high-strain dynamic testing, ensure structural integrity of the completed piles and how redundant integrity testing methods complement good construction and inspection practices add confidence in the quality of the foundation system.

Sep 8, 2021

By Gang Guo, Zhong Liu

"In response to an increasing demand of anchored structures for underground space and transportation infrastructure in China, an innovative underreamed ground anchorage system was created. The novel anchorage system has provided more efficient functions with higher capacity at lower cost, because of the enlarged cylindrical body (known as ECB) sealed in capsule at bottom of anchorage. This paper presents the detailed structure of innovative anchorage system and its special features. To investigate the bearing mechanism of new anchorage, we evaluate its performance and failure mode based on the experimental results, and also indicate its strain-hardening load-displacement relationship. Unlike the shaft anchorages, it is identified no overall failure to be found in soil surrounding the underreamed anchorage. More importantly, the anchorage capacity is governed by the base resistance, which takes more than 80% of total pullout capacity resulting from the contribution of ECB. Finally a case history of anti-floating project introduces the new combined construction approach and procedure, which has provided the contribution to the quality control and cost efficiency.INTRODUCTION AND BACKGROUNDThe construction boom over two decades in China has resulted in an increasing demand for underground space and slope stability. The infrastructures market requires the more efficient anchorage systems for retaining structures, resisting uplift forces and slope protection. The major concern focuses on gaining higher capacity and lower cost resulted from perfecting anchorage systems. There are three main anchorage systems designed to achieve the above objectives: ? single bore multiple anchorage system (Barley 1997), ? regroutable anchorage system (Smoltczyk 1991), ? underreamed anchorage systems (Xanthakos 1991). Generally, the concept ? comparing with the other two, can be more competitive due to its distinct advantages. To improve the performance and durability of ground anchorages under the complex geological conditions and diversified engineering requirements, a number of different underreamed anchorage technologies had been used, which included cone - shape anchorage described by Liao, Wu and Shu (1997) in Taiwan, Soilex anchorage developed in Sweden (Massarsch et al. 1997), Soletanche anchorage proposed in France, blasting anchorage used in Czechoslovakia (Hobst and Zajic 1986), jet-grouting anchorage innovated in Europe (Anon 1988), as well as deep mixing anchorage created in Japan (Cheng et al. 2000).The underreamed anchorage systems have the remarkable advantages compared to the shaft anchorage system. However, there are also some weaknesses inherent in the underreamed systems. For instance, the mechanical underreamed anchorage is unsuitable in sand or waterbearing ground, because the enlarged hole is easy to collapse, and it is hard to ensure the quality of anchorages. On the other hand, relying on the blasting in deep hole, the geometrical space and dimension of enlarged hole is uncontrollable, meanwhile, the continuous blasting operations may easily cause the serious ground deformation and the negative effects to the completed anchorages."

Jan 1, 1900

By Dipl. -Ing. (FH) Thomas Schmitt, Dr. Melvin England

Foundations in Geneva are difficult and expensive due a large overlayer of clay and silt above competent bearing material in the moraine. Common foundation schemes use deep barrettes or bored piles, first passing large, weak layers of soil before finally reaching acceptable, solid moraine with reasonable values of skin friction and end bearing resistance, thus requiring further deep penetration for the necessary length for load transfer in the moraine. Depths of more than 60 m (200 ft) in Geneva are common in this region. At the Onyx-Project Geneva Implenia Foundation Company also encountered these circumstances. Despite usual solutions Implenia referred to an old and well known, but still intelligent and in today’s words smart, efficient and economical solution. Using small shafts, passing the large layers of clay and silt, ending with the pile toe in the underlaying moraine with a belled or underreamed base was the technic adopted to save drilling time, reduce spoil and concrete, so finally reducing the CO2 footprint. Piles with enlarged base (“belled” or “underreamed”) are reported at the beginning of the 20th century, for example at Chicago, which has a quite similar geotechnical structure as Geneva with the need of deep foundations. The first pile base enlargements were built in hand-dug caissons with wood lagging and steel ring bracing. In the 50s and 60s piling works were more and more mechanized, driven by the development of more powerful cranes and specialized drill rigs. Additionally the first tools for mechanized base enlargement were invented around that period. This report describes the project situation at Geneva, the drilling and enlargement technique of the pile base, the verification of the design values with an in-situ bi-directional load test and the smart execution by reduction of CO2 and costs.

May 1, 2022

By Cheng Lin, Guoming Lin

"This paper presents a case history for the design, construction and long-term performance monitoring of a driven prestressed concrete (PSC) piled foundation supporting a large liquefied natural gas (LNG) tank in Savannah, Georgia, USA. Following a geotechnical investigation, a design stage pile test program was performed with three objectives: to study the densification effect from pile driving on the liquefaction resistance, to test axial and lateral pile capacities, and pile behavior under lateral loads. The test program comprised five piles driven on a test pad constructed adjacent to the tank foundation. Cone penetration testing (CPT) was performed before and after pile installation to test soil densification effects from the pile driving and liquefaction potential was re-evaluated based on the soil densities after pile installation. The axial load tests involved static load testing, high strain dynamic testing, and Statnamic testing. This paper presents the findings of the densification effects, compares results from different axial testing methods and discusses the procedures to use the load test results in the pile design. The paper also comments on the construction issues and presents performance data with 10 years of monitoring.1. IntroductionThe project site is located at the Kinder Morgan’s Elba Island LNG Terminal on the Savannah River which is three miles downstream of the downtown Savannah, Georgia. This LNG terminal was initially developed in the 1970s as an LNG import terminal. The facility includes five LNG storage tanks with two larger tanks which were constructed in 2003 and 2006, respectively. The terminal is currently being converted into a liquefaction and export facility. This paper discusses pile foundations for Tank D4 which is a double walled insulated steel tank built to hold one million barrels of LNG in 2003. This tank has an outer tank diameter of 258 feet, an inner diameter of 252 feet, and liquid height of 113 feet. A number of geotechnical challenges were present in the foundation design and construction.??The site is a typical coastal deposit site featuring a thick layer of very soft under-consolidated clay (up to 40 feet in thickness);??The bedrock is a couple of thousand feet deep;??There is a sand layer that is liquefiable under a high seismic design category (0.5% possibility of exceedance in 50 years)."

Jan 1, 1900

By Saieb Haddad, Henry Pate

"Building retaining walls in an urban area is becoming more difficult due to right-of-way restraints. Using standard concrete cantilever walls requires a construction easement behind the walls for installation, which for the most part is unavailable. To install these types of walls in a limited right-of-way requires extensive temporary walls to minimize the construction easement. Top-down construction walls utilizingtie-back anchors for support require either the purchase of the right-of-way or underground easements in the area of the anchors.These problems faced the Department on Interstate 75 widening in Knoxville, TN in an area of a large cut. A multi-story Insurance Building and a large commercial Retail Center were located at the top of the cut. To prevent any impact on the buildings, the walls had to be placed within a limited area. The option of buying the properties was prohibitively expensive. Due to the height of the two walls and the variability of the underling rock line, contiguous caisson pile cantilever walls were contemplated as the only wall type that would be appropriate. The cost of the two walls was estimated to be very close or even higher than the cost of purchasing the two buildings. The Department believed that there must be a better way to deal with the problem. A vertically tied-down pile frame wall constructed from the top-down with a concrete facing was developed. This allowed the construction of the walls to be restricted to the available limited area and provided substantial savings for the State.INTRODUCTIONThe widening of I-40/75 has been a major transportation project in the Knoxville area which is being constructed by the Tennessee Department of Transportation. The project includes 18 Retaining Walls and 13 Bridges.Two of the 18 Retaining Walls, refer to Figure 1, are to support two valuable properties, one being an insurance company housed in a multi-story office building and the other a suburban shopping center which were appraised at $13.0 million and $5.0 million respectively. Due to the 31 ft. (9.5m) maximum height of each of the two Retaining Walls and the limited Right-of- Way of 15.0 feet (4.6m), a contiguous caisson pile cantilever wall was proposed for each of the two retaining wall sites with an estimated cost of $12.0 million each. The contiguous pile cantilever Wall is comprised of a line of caisson piles socketed into underlying competent bedrock. The design required that 4 ft. (1219mm) dia. piles be installed at 6 ft. (1.83m) centers, socketed into rock in order to provide lateral stability and restrict lateral wall movement to acceptable limits. The line of caissons would be fronted with a cast-in-place concrete face wall"

Jan 1, 2007

By Ashirbad Satapathy, Sanket Rawat, Ramanand Shukla, Ravi Kant Mittal

Bearing capacity factor (Nq) and Adhesion factor (α) are the key parameters for analyzing the load carrying capacity of pile foundations embedded in cohesionless and cohesive soils respectively. Numerous models are available in the form of charts or equations for the computation of these parameters and hence, have been adopted by most of the International and National standards. Indian Standard for the Design and Construction of Concrete Pile Foundations, IS 2911–Part 1 (2010), also makes use of charts detailed in its Annexure B. However, the sources of these charts have not been specified clearly, making it difficult to back-refer to the actual models to assess their basis for resolving any critical scenarios encountered during design. The present study aims at acquiring a distinct understanding of the development of these charts in order to bring more clarity to the design process of pile foundations. The given charts have been compared with various models specified in existing literature and international standards for the calculation of Nq and α for both driven and bored piles and hence, the basis of Indian Standard charts has been identified. Moreover, it is evident that the use of these charts complicates the process of automation of analysis and design of pile foundations as well as the associated optimization studies. Additionally, the manual entry of data especially, from the logarithmic graph of Nq, escalates the chances of error thus, making it a critical concern for design offices. Therefore, this paper also presents a non-linear regression model for Nq and α, developed using NCSS software for both driven and bored piles. Through multiple iterations, the value of coefficient of determination for Nq and α has been found to reach greater than 0.995. The developed equations can be simplistically used for both manual and automated analysis of pile foundations.

Nov 1, 2022

By Sanjay Gupta, Sorabh Gupta, Ravi Sundaram

A geotechnical forensic evaluation of piles for an industrial facility in Haryana was performed to assess the quality of the piles and to evaluate piles installed using two different types of rigs. Low strain pile integrity tests were performed on all piles to assess the pile length and possible presence of structural defects. Coring was done through questionable piles for the clinching evidence of concrete quality and pile length. Probe holes adjoining piles helped confirm the bulging of piles at shallow depth. The paper highlights the importance of implementing a well-planned quality assurance program to confirm that all piles installed are of the desired quality.

Sep 1, 2022

By Thomas Trochalides

Newtown Creek Water Pollution Control Plant in Brooklyn, NY is the largest of 14 Water Pollution Control Plants in New York City. It services over 1 million people with a current processing capacity of 310 million gallons daily. Upgrades to the plant have been underway since 1998. This paper details the foundation elements installed in three separate contracts during 2009: NC-41F, NC-36G, and NC-47G. The elements are Concrete-Filled Pipe Piles, H-Piles, Steel Sheet Piling, Secant Walls, Drilled Caissons, and High Capacity Micropiles. Soils on the site consist of fill over organic silty clay and silty sand. Beneath the organic layers lie lake sand and varved silt and clay, sitting atop glacial till and rock. Due to Federal Mandates, certain plant capacity and secondary treatment requirements had to be met by specific dates. Failure to meet the requirements would have an adverse affect on the NYC areas being serviced. Further complicating the project, the existing plant operations had to be maintained throughout the entire construction phase. To accommodate the constraints of the project, new specialty equipment and several key redesigns were used to maintain construction schedules

Jan 1, 2010

By Seth H. Hamblin, Leo J. Hart, John E. Regan

The Route 6 /10 10 Interchange Design/Build project, located in Providence, Rhode Island, involves the design and construction of five (5) new elevated bridge structures to replace and reconfigure the existing interchange and to provide a link between Route 10 northbound and Route 6 westbound. Due to site logistics, headroom restrictions, and depth to bedrock, 50 ton drilled micropiles installed in the deep medium dense sand strata were initially proposed as the deep foundation solution. Post project award, Geosciences Testing and Research, Inc. (GTR) performed various analyses and developed an alternate driven pile solution using steel Tapertube. The results of these analyses indicated that driven steel taper tube and steel pipe piles could develop greater capacities than the drilled micropiles in the granular soil layer, thereby reducing the number of foundation elements, decreasing construction schedule and providing a more cost effective foundation alternative. A comprehensive driven pile load test program was subsequently executed by GTR and the Design Build Team led by Barletta Heavy Division of Canton, Massachusetts, to assess the performance of Tapertube and steel pipe piles, including pile drivability, load-deformation characteristics under static and dynamic loading, and to develop site-specific design parameters in two (2) distinct test areas. The test pile program included dynamic, static compression, tension and lateral load tests on each test pile. Load test measurements were automated with embedded Vibrating Wire Strain Gages (VWSG) to measure load transfer with depth. The execution and results of the successful pile load test program are presented and offer unique case study and valuable data for the use of Tapertube piles on deep foundation projects in the New England region INTRODUCTION The Rhode Island Department of Transportation (RIDOT) Route 6 / Route 10 Interchange is located west of downtown Providence. Originally constructed in the 1950’s as a highway bypass around the historic Olneyville neighborhood, the interchange consists of a series of nine (9) bridges and ramps that serve as a vital east-west link between Interstate 295, 95 and 195. Based on recent bridge rating assessments, seven of the nine bridge structures are rated “structurally deficient”. With many bridge structures shored with temporary supports as many as 15 years ago, the interchange is in critical need of replacement. In 2018, RIDOT awarded the Route 6/10 Reconstruction Design-Build Project to 6/10 Constructors, Joint Venture. Led by Barletta Heavy Division of Canton, Massachusetts, the Design Build team includes O&G Industries, DW White Construction, Aetna Bridge Co. and AECOM. The scope of work includes the replacement of the bridges and ramps, and will provide direct access from Route 10 northbound to Route 6 westbound. Valued at over $400M (US), this is currently the largest project awarded in RIDOT history.

Jan 1, 2019

By Lois G. Schwarz

I did a project (Sungai Piah) as a consultant to your firm in Malaysia, where we were faced with a similar situation as sketched out in your question. The following is what we did for the grouting of the primary holes, which were both located upstream of the plug as well as downstream: We used a hydrophobic MDI based semi-rigid polyurethane prepolymer in the first phase of the grouting operation when grouting under water flow conditions. Then in the second phase and also for the contact grouting we used a two component water compatible polyurethane elastomer. And then for deeper formation grouting, when all the water flow had been stemmed in the vicinity of the plug, we used a regular (balanced stable) cement based grout. So it may not exactly answer your question, but we first used hydrophobic grout because it is very efficient to grout a formation through which water flows. We didn't stop all the leaks day-lighting downstream of the plug or all water running through the formation near the plug, but the flow of water through the rock formation adjacent to the plug was reduced by 99.9%, after completing the urethane grouting. This facilitated the placement of cement based suspension grouts without wash-out.

Feb 10, 2003

By Jesús E. Gómez

Verification and production testing of soil nails requires debonding the upper section of the soil nail to isolate the portion of the soil nail intended for testing within a specific ground type. In pre-drilled soil nails, debonding can be accomplished relatively easily because the bar can be fitted with a debonding sheath before its installation. However, debonding of hollow core bar soil nails requires special procedures to achieve the intended result. This paper is a summary of the Federal Highway Administration (FHWA) Hollow Bar Soil Nail (HBSN) Test Program, which is described in detail in FHWA-CFL/TD-10-001. The program was developed to establish a suitable debonding procedure to test hollow core bars in soil nailing applications, and to initiate a database on typical bond values of HBSNs. The investigation showed that it is possible to debond hollow core bars for testing. It was also found that hollow core bars installed in granular soils may present ultimate bond values that are significantly higher than those typically used for design of conventional pre-drilled soil nails.

Jan 1, 2011

By Alan D. Fisher

Amtrak made a decision to replace an aging bascule bridge with a vertical lift bridge for their crossing of the Thames River in New London, Connecticut. The new lift bridge occupies the same alignment and shares the same foundations as the bascule span. During construction the deep foundation caisson supporting the bascule span settled and tilted. Investigation into possible reasons revealed interesting historical facts, both of the construction of the innovative open well caisson foundations and of the state-of-the-art in tremie concrete placing methods in use at the turn of the century. This paper describes both of these topics.

Jan 1, 2013

By Patrick van der Schaaf

"During 2016, foundation piling works were completed to allow for the construction of a production and storage/handling terminal in Rotterdam. It is there that steel foundations will be produced for offshore wind farms and the oil and gas industry. Several Dutch contracting companies were involved in constructing: foundations for an assembly hall, a barge quay and a deep-sea quay wall. For the hall foundations, cast in situ concrete vibro piles were created. Open ended steel casing piles were also installed due to very high cone resistances which made it impossible to perform cast in situ piles in certain areas. The quay wall was constructed with open ended steel casing piles in combination with sheet piles. A deep-sea quay wall was also constructed to provide enough storage area for the offshore mono piles. This project was unique and challenging due to the use of different foundation technologies in challenging circumstances and soil conditions. This paper will give an insight into the Dutch use of varying foundation piling techniques for deep-sea quay wall constructions. It can be concluded that even experienced local contractors can be surprised by variations in soil conditions. It will also show how the contractors adapted to the difficult circumstances.PROJECT OUTLINEThe project consisted of a barge quay near the assembly hall with a length of 500 metres, width of 42 metres and a height of 35 metres, and a deep-sea quay wall 480 metres in length. This paper concentrates on the foundation works for the construction of the deep-sea quay wall. The construction of the deep-sea quay wall consisted of a combination of open ended steel casing piles with a diameter of Ø 1420 mm and a wall thickness varying between 21 and 23 mm. The lengths of the steel casing piles varied between 32 and 37 metres. Between the steel casing piles triple PU 28 sheet piles were installed with lengths varying between 26 and 29 metres. In the Netherlands, a combination of open ended steel piles and sheet piles is known as a “combi wall”. For the deep-sea quay wall a steel combi wall was shored with steel H- section profiles that were driven in a raked position whilst being injected with grout, so called MV-piles. The MV piles for this project consisted of steel HEB 600 sections with lengths from 52 up to 59 metres and were installed with angles varying between 42.5 and 47.5 degrees. For a detailed overview regarding the project specifications reference is made to table 1 which is presented below."

Jan 1, 1900

By Larry Rayburn

Augercast piles evolved in the late forties from the process of pressure grouting open holes backfilled with stone. In 1956, a patent was issued for a cast in situ pile by pumping high pressure grout through hollow-stem, continuous flight auger as the auger is gradually withdrawn from the ground. The patent rights expired in 1973 and the use of auger-cast piles greatly expanded with most large deep foundation contractors now installing augercast piles. At one time augercast piles had a bad reputation, partly because of not having a blow count to give some engineers a confidence factor and there were some quality issues. Over the years the quality issues have been eliminated and I am sure the augercast is the most installed pile in private industry and is now being used by some State Agencies.

Jan 1, 2005

By Reda Mikhail, M. Birkan Bayrak

The Washington State Department of Transportation (WSDOT) State Route (SR) 167/70th Avenue East Vicinity Bridge Replacement Design-Build project is located in Fife, Washington. This $40 million project consists of replacing the existing 70th Avenue Bridge over Interstate 5 (I-5) with a single-span bridge of about 220 feet long with approach embankments. The subsurface conditions along the new bridge alignment generally consists of alluvial deposits with high potential of liquefaction overlying glacially overridden deposits. In the early stages of the project, drilled shafts were considered as the deep foundation system; however, after an additional subsurface investigation is completed at the site, driven pipe piles were selected as the deep foundation system. Bridge abutments are supported by 24-inch diameter, 80-foot-long open-end driven steel pipe piles. The pile length was determined to bypass a relatively thick liquefiable zone and to tip the piles above what could be compressible soils. The use of advanced seismic analysis was instrumental in optimizing the pile length. The dynamic testing performed on numerous piles indicated what could be unique soil setup factors compared to those measured in local projects as well as those reported in national design manuals. Detailed discussions of the pile foundations design and construction is presented in this paper.

Sep 8, 2021

By Masaki Kitazume

"Many earthquakes take place every year in Japan, in which the 1995 Hyogoken-Nambu earthquake and the 2011 Tohoku earthquake induced both a humanitarian crisis and massive economic impacts. As liquefaction which occur in a loose and saturated sand layer, induces quite large damages of infrastructures, the importance of liquefaction mitigation has been emphasized to minimize earthquake disasters for many years. Many kinds of ground improvement techniques based on various improvement principles have been developed for earthquake disaster mitigation. Among them, the grid type deep mixing method has been often applied to liquefaction mitigation. In the method, the stiff grid walls are constructed by mixing the soil and binder in-situ, which are expected to restrict the shear deformation of the soil within the grid walls so that the pore water pressure generation can be remained small. The high applicability of the method was confirmed in several earthquakes, including the 1995 Hyogoken-Nambu earthquake and the 2011 Tohoku earthquake. In this paper, the development of the method, some applications of the deep mixing method to earthquake disaster mitigation are briefly introduced. INTRODUCTION In Japan, many earthquakes take place every year in Japan, in which the 1995 Hyogoken-Nambu earthquake and the 2011 Tohoku earthquake induced both a humanitarian crisis and massive economic impacts. As liquefaction induces quite large damages, the importance of liquefaction mitigation has been emphasized to minimize earthquake disasters for many years. Table 1 shows the amount of damage to port facilities (Noda, 1991). According to the table, the amount of damage when liquefaction takes place is about 20 to 50 times larger than that without liquefaction. This highlights the importance of liquefaction mitigation to minimize earthquake disasters. There are many kinds of soil stabilization techniques developed for liquefaction in Japan. Among them, the deep mixing method (DMM), an in-situ cement stabilization techniques, was developed in 1970s in Japan and has frequently been applied to improvements of clayey and sandy soils (Kitazume and Terashi, 2013). The grid type DMM has been often applied to prevent liquefaction, where the grid of stabilized column walls function to restrict generation of excess pore pressure in the soil within the walls by confining the soil particle movement. The improvement effect of the method was first evaluated in the Hyogoken-Nambu earthquake in 1995 and was also evaluated in the Tohoku earthquake in 2011. In this paper, some successful performance of the deep mixing method to earthquake disaster mitigation in the two earthquakes are briefly introduced."

Jan 1, 2015

By Joel L. Volterra

Since 1910, Mueser Rutledge Consulting Engineers (MRCE) has regularly provided professional engineering services including inspection of pile load tests. Historically, such services included on-site inspection of the driving of test piles and subsequent static load tests by qualified Geotechnical Engineers. Load testing procedures are specified by local or State Building Codes, locally the 1968 Building Code of the City of New York (1968 BCCNY). Between 1968 and 2008, the 1968 BCCNY required a minimum 48-hour hold period for standard loads per pile type, an extended 96-hour hold period for higher capacity piles, and a settlement criterion that the pile maintain a test load equal to two times the design load with less than 0.012 inches of settlement over the last 48 hours of the hold period. Effective July 2008, the new 2008 BCCNY shortened the hold period and relaxed the settlement criteria to that which is more similar to other governing codes and standards such as the International Building Code (IBC 2006) and the American Society for Testing and Materials (ASTM). MRCE implemented an automated load test monitoring system to reduce costs and to alleviate or minimize overnight and off-hour staffing for load test readings. Initially, a series of linear variable differential transformers (LVDTs) and data loggers were included in the Contractor?s load test setup to electronically record pile head settlement and where applicable, settlement of telltales installed to varying depths in the pile. A pressure gage was subsequently added in the hydraulic line, then a load cell, strain gages, and remote access using modems. The ease of the setup and modular adaptive nature of this system have proven it to be a useful tool and improved our ability to better serve our clients and manage our pile load testing services.

Jan 1, 2008