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By Rolf Katzenbach

The principle questions related to the design of deep foundations especially in soft soils are the stability and the cost optimised settlement reduction to prevent possible damages and to minimise the deformations of the adjacent infrastructure. The present develop­ments in the design of deep foundations lead to the design approach of the Combined Pile-Raft Foundation (CPRF) which offers a lot of new possibilities, e.g. the utilisation of the CPRF for horizontal loading or the use of the subsoil as a geothermal storage system.

Jan 1, 2006

By Hui Yongning

This paper presents a simulating test of constitutive relation of soil anchor in laboratory and puts forward a new plastoelastic mechanical model, on which a new calculating formula of elastic and plastic limit bearing capacity for soil anchor is suggested and two engineering projects verify that this method is adaptable.

Jan 1, 1991

By Chu E. Ho

Jet grout column formation at large depths are prone to several uncertainties, such as inaccuracy in setting out boreholes, drilling deviation, soil variability and reduced jetting energy at the nozzle. This would result in shorter cutting distance of the jet, with potential lack of interlock between grouted columns. A design strategy for mitigating the risk should include a soil investigation program aimed at discovering potential variability in soil conditions at the locations of jetting. Determination of soil strength profiles with depth would be useful for evaluation of jetting parameters and prediction of the achievable cutting distance at any depth. Selection of design column spacing should include allowance for setting out accuracy, verticality of the boreholes and the achievable jet cutting distance. For deep jet grouting operations, it would be necessary to take into account the energy losses at the nozzle inlet; however the increase in the presiding pressure at the nozzle outlet at depth is small relative to the range of jetting pressures commonly employed and would not affect the cutting distance to any significant degree. Design column spacing should not be so close as to cause problems with ?masking? which may lead to localized ungrouted zones of soil. For effective field control, boreholes should be cased up to the top elevation of the grouted zone so that the orientation of the borehole can be measured prior to grout injection. An analytical equation for calculating the cutting distance is proposed for adjusting jetting parameters where necessary to compensate for drilling deviation and changes in soil conditions. It is preferable that jet grouting trials be executed at elevations that correspond to the actual production jet grouting depths for accurate evaluation of jet cutting performance.

Jan 1, 2008

By I. H. Wong

The large diameter caisson foundations and their construction methods for three 50 to 60 storey high buildings in Singapore are described. The caissons are 5 m to 8 m in diameter and 40 m to 100 m deep, excavated either by hand or mechanised excavators or by drilling and blasting. Performance of the 50 storey DBS Building is described.

Jan 1, 2010

By Radianto Elprama

For the realisation of the underground railway line RandstadRail in the city area of Rotterdam a bored tunnel is under construction. Diaphragm walls up to a depth of about 40 m were used to construct the building pits for the start shaft, the Blijdorp Station and the end shaft. The water tightness of the diaphragm walls was determined by leakage tests that were executed after the construction of the walls, but prior to the excavation of the building pits. The tests showed satisfactory results with a hydraulic resistance of the diaphragm walls of at least 500 days. To determine the water tightness of diaphragm walls it is recommended to follow the specific procedure as described in this paper.

Jan 1, 2006

By Gerry Houlahan

The east span of the 3.5 km long SF-Oakland Bay Bridge is supported by different types of foundations along its span. Starting from the west, its first 460 m section comprising twin concrete box-girders is supported by sands and rock on Yerba Buena Island. A 620 m long steel suspension span then bridges a 25 m deep channel that is formed in sediments overlying rock. Twin concrete box girder structures, each 2.4 km long, complete the stretch over the remainder of San Francisco Bay to the engineered earth fill landing at its east end. For most of its length, the Skyway bridges water 3 to 10 m deep over soft surficial Young Bay Mud. The foundation types include spread footings with hold-downs, steel and concrete piles that are set in drilled rock sockets up to 3 m in diameter and 2.5 m diameter steel tubular piles driven to penetrations of up to 100 m. The design and construction-related considerations are presented. The different foundation types, influences of the site geology and earthquake demands on the substructures are discussed. The seismic motions of the bridge superstructures and substructures, as well as the depth-varying soil motions, influenced the foundation design. Together with performance-based design criteria, including post-earthquake footing displacement limits, these seismic demands influenced various aspects of the foundation design, including the use of battered and vertical piles.

Jan 1, 2005

By Virendra Singh

The load settlement behaviour of single pile or pile group may be obtained using computer based methods such as the finite or boundary element techniques. An alternative method of obtaining the vertical soil stresses adjacent to the Pile is presented Based on calculated stresses consolidation settlement for Piles foundation is obtained. This approach may be computationally more attractive than the more general finite or boundary element techniques.

Jan 1, 1996

By B. N. Hira

A multistoreyed residential complex was at the penultimate stage of construction by ONGC at Nazira, Assam. The site was situated at high earthquake zone. The subsoil was very weak and contained soft to medium clay with water table almost at the ground level. The bearing capacity of soil was quite poor particularly with predicted settlement beyond permissible limit. In this situation, the conventional shallow and deep foundations were found uneconomical and ground improvement with granular piles was considered as the viable solution. ONGC approached the Central Building Research Institute with the request to design granular piles along with R.C.C. foundation and other suitable cost effective measures. CBRI collected relevant geotechnical informations and supplimented the data by conducting field tests at site and laboratory tests at Roorkee. Rational design of 30 cm dia. and 5.00 meter deep granular piles were suggested with isolated and combined RCC footings over the reinforced soil. In addition to several structural and geotechnical advantages, the granular pile foundation provided considerable economy in the cost of construction. The paper presents the salient geotechnical and structural informations of the challenging project and provides the design details of the innovative granular pile-system. It also furnishes the design approach of the RC footings and other elements of the foundation.

Jan 1, 1996

By Tracy Brettmann, Will Bohlen

An innovative retaining wall design consisting of tangent drilled shafts with supplementary seal piles was used to limit continuing bank erosion along the Brazos River in Southeast Texas. The riverbank erosion had progressed to where it was threatening the stability of both the bridge abutment and corresponding approach embankment of the heavily travelled Highway 99 bridge at this location. A tangent pile design was selected because it was both much faster to install and more cost effective than a secant pile system. The design included both 5.5-ft and 10-ft diameter shafts with depths up to 130-ft and comprised both anchored and cantilevered sections. Supplementary seal shafts were also installed between the structural tangent drilled shafts to help plug any gaps between the tangent shafts. The plumbness and diameter of the shafts were tested using a sonic caliper to make sure the shafts were installed within the specified tolerance. The initial design had to be revised when a record flood from Hurricane Harvey impacted the site during construction. Introduction The Fort Bend Grand Parkway Toll Road Authority (Owner) needed to protect the north bridge abutment with a retaining wall system due to rapidly eroding conditions of the Brazos River banks within the 300- feet-right-of-way of the State Highway 99 Jodie Stavinoha Bridge. The extent of the local scour and erosion along the north bank of the Brazos River has caused concern for the structural integrity of the bridge. The magnitude of the erosion along the north bank at the location of the bridge has been measured at about 120 feet over three recent hydrologic flood events locally referred to as Memorial Day 2015, Memorial Day 2016, and Tax Day 2016. During construction, a new record flood level occurred due to Hurricane Harvey in August of 2017 that resulted in a portion of the retaining wall needing to be redesigned due to even more erosion occurring. The Brazos River is an actively eroding and meandering alluvial river plain that naturally meanders and migrates over time. The processes of bank erosion and meander migration were ongoing before the bridge was constructed and will continue in the future. These recurring major flood events, however, rapidly increased the rate of erosion in just a few years. Background. Due to the need to protect the bridge as soon as possible, the Owner selected a project team consisting of the designer, general contractor and specialty deep foundation contractor prior to final design to work together in developing a cost-effective design that could be implemented rapidly. The project team initially considered both a secant pile and tangent pile retaining wall system using drilled shafts. After reviewing various alternative designs, a tangent pile wall with seal piles was selected based on both cost effectiveness and speed of installation. The tangent pile with seal pile option was approximately 20 percent lower in cost and 50 percent faster to install.

Jan 1, 2018

Jan 1, 1989

By Mait Mets

In Estonia, the deformations monitoring of 1500 buildings are currently under investigation, buildings on pile foundations make up 10 per cent of these. In the following text we will be considering the behaviour of pile foundation buildings in various parts of Estonia, in differing geotechnical conditions.

Jan 1, 2002

By David J. White

The decreasing availability of land in urban areas, and the increasing demand for urban development is leading to the construction of taller and heavier buildings at increasingly marginal sites. Such structures usually require founding at depth and modern construction methods are making the economics of piled foundations ever more attractive (Salgado, 1995). However, the urban environment is not suited to pile driving. Conventional dynamic installation techniques (i.e. drop hammer or vibro-piling) induce vibrations and settlement in a zone close to the pile, and cause noise and dust pollution. Damage to existing structures resulting from pile driving vibrations is not uncommon (Tomlinson, 1986).

Jan 1, 2000

By Wolfgang G. Brunner

The closing of the gap in the European waterway- net is one of the big and challenging traffic projects following the German reunification. The water canals in the North German plain connect the Rhine river, the border between Germany and France, with the Oder, the German border river to Poland. As early as in the 30's of the 19th century the planning and construction of a ship- lift and a canal bridge started, in order to close this last big gap in the system between the Mittelland Canal and the Elbe- Havel Canal near Magdeburg. This main waterway connects the West of Germany, known for its coal mines and steel mills, with the capital Berlin, and from there it goes on into Poland. The building activities started in 1934 but came to a complete stop in 1942 because of the war. The communist government in East Germany was not interested in continuing this huge project, including the ship lock Rothensee, the canal bridge crossing the river Elbe, the former border river between West and East Germany, and the lock Hohenwarthe due to lack of political backing along with low construction capacity.

Jan 1, 2000

By Louis Donolo

New buildings in today's urban environment, especially in down-town areas, invariably involve the construction of multiple level basements. Used for parking, storage and commercial space, these underground structures normally extend 30 to 50' and more below grade and, to make optimum use of expensive land, they usually occupy the full site right up to street/sidewalk and property lines. SOIL SUPPORT SOLUTIONS Building these basements requires vertical excavation, and consequently, a temporary soil support system which will eventually be replaced by the permanent foundation walls of the structure.

Jan 1, 1987

By Nicolas Denies, Gust Van Lysebetten, Bart Lameire, Jan Maertens, André Vervoort, Noël Huybrechts, Flor De Cock

"Abstract Originally developed for ground improvement works, the deep mixing method (DMM) has increasingly been applied in recent years for the realization of soil and water retaining structures and as alternative to traditional foundation solutions. From practice, there is a real need for practical guidelines dealing with the execution, the design and the control of such applications. With the aim of developing such guidelines, the BBRI ‘Soil Mix’ project was initiated in 2009. Within this research project, deep soil mix (DSM) material from 38 Belgian construction sites has been tested. In spite of the large advances in the mechanical characterization of the DSM material, one major issue remains the representativeness of the typical core samples in comparison with the real scale behavior of the soil mix elements. There is among others the question of the influence of the unmixed soft soil inclusions on this behavior and the issue of the scale effect which must be considered in the design. In order to investigate these questions, 8 large scale UCS tests and 17 large scale bending tests have been performed on excavated soil mix elements. The present paper discusses results of this experimental campaign, presents some research perspectives and highlights different aspects related to the design of soil mix elements for the realization of retaining wall or foundation solution.INTRODUCTIONSince several decennia, the deep mixing method (DMM) has been used to improve the strength and deformation characteristics of weak soils. In recent years, deep mixing has increasingly been applied – in Belgium and in other countries – for the realization of soil and water retaining structures and alternative foundation concepts. With regard to the execution of the DMM, one can refer to the European standard EN 14679 on deep mixing (2005) that was elaborated under the umbrella of CEN TC 288 “Execution of special geotechnical works”. However, from practice, it has been experienced that this execution standard does not provide enough pragmatic information and guidelines, in particular for the more recent applications of the deep mixing method (with retaining and bearing functions). The same need by the sector for guidance rules linked to design aspects in the context of Eurocode 7 was experienced as well. With the aim of developing such guidelines and in order to provide feedback to the European standardization platforms, the Belgian Building Research Institute (BBRI) has initiated the BBRI ‘Soil Mix’ project (2009-2013) in collaboration with the KU Leuven and the Belgian Association of Foundation Contractors (ABEF), the Belgian branch of the EFFC. Within this research project, deep soil mix (DSM) material from 38 Belgian construction sites, with various soil conditions and for different execution processes (CVR C-mix®, TSM and CSM), has been tested (Denies et al., 2012)."

Jan 1, 2014

By M. Makarchian

Existing buildings sometimes experience excessive settlement under their design loads, or due to increased foundation loading, if a change of building use is required. One of the oldest and widely numerical study has been carried out of a simple idealised problem of an underpinned rigid circular foundation to better understand the behaviour of pile used for underpinning and load transfer mechanism from an existing foundation to the underpinning piles. The finite element method has been used for this analysis, with the soil treated as a two-phase elasto-plastic material. It is found that the effect of the length of the pile becomes more significant as pile length increases. As would be expected, the earlier the pile is installed, the less is the final settlement.

Jan 1, 1996

By W. D. Guo

With an experimental apparatus developed recently, model tests on piles were conducted in sand subjected to triangular soil movement profiles. Four instrumented piles tests are reported, which show the pile behavior predominantly determined by soil sliding depth. Axial load can create additional bending moment and pile deflection, which also make mode of pile-soil interaction change with sliding depth. Limiting resistance was found 1.5~3 times higher than currently used for laterally loaded piles in sand.

Jan 1, 2006

By Emad W. Shublaq

Contractual site plans are implemented for executing pile foundations (5 x 5) at segmental concrete bridge. Project schedule demands have forced the contractor to find out the most economical procedure in achieving the goal. This paper presents a site management technique which is applied by the Contractor. This was found to be fruitful and as much as 60% saving was gained.

Jan 1, 1992

By S. Merjan

Three papers were presented for discussion at the conference: 1) Instrumented driven steel tube piles at Canary Wharf; author: A. R. Gaba, United Kingdom. The author described the Canary Wharf development in the London Docklands, and in particular, the decision to build over the water by driving open-ended steel piles 25m in length into the sands below the soft estuarine deposits. The tubes were then filled with concrete above the sand plug (usually 17m below pile head). Three trial piles were instrumented with: a) resistance strain guages on the inside of the tubes; b) vibrating wire guages on the re­inforcement of the concrete. The trial piles showed elastic behaviour in five cycles of lateral loading, while the verticle load tests showed a definite bi-linear load-settlement behaviour. The initial stiff portion was a result of frictional staff resistance, both inside and outside the tube, with the soil at the base contributing at higher settlements. Loads were taken to three times working load, with no imminent signs of failure.

Jan 1, 1991

By Fabrice Mathieu

The Cutter Soil Mixing (CSM) provides a cost effective solution for the rapid construction of retaining and cut-off walls using new equipment developed from diaphragm wall cutter technology. CSM consists of cutting and mixing drums mounted on compact hydraulic motors. Soletanche Bachy CSM has been designed to leave the space above the tool free, thereby mixing the soil efficiently during all the phases of the wall construction, with high penetration rates. The precise positioning and verticality of the wall is achieved using a kelly bar and full monitoring. Soletanche Bachy CSM is a versatile equipment which can be mounted on various carriers: pile rigs, hydraulic crane, carrier equipped with telescopic mast. The major phases of Soletanche Bachy CSM development are presented, including the results of an extensive trial carried out in Le Havre (France). The soil consists of hydraulic fill with soft soil lenses overlying sandy deposits. 20m deep panels were constructed to support a rectangular shaft. During the construction, and after its completion, the shaft was subjected to an extensive series of tests followed by a partial excavation. The paper discusses also the future development of the technique and its potential applications.

Jan 1, 2006