This video contents a general description of the EB technology with some practical details. This ... more This video contents a general description of the EB technology with some practical details. This technology is a step forward in QA/QC of deep foundations with remarkable savings in time and costs, beside the valuable geotechnical information obtained during the installation and expansion of each EB with cement grout. The record of volume and grout pressure plus the knowledge of the shape, allows to have a well known foundation element (pile or anchor)
The city of Santa Cruz, Bolivia, is historically dominated by houses and three to five storey bui... more The city of Santa Cruz, Bolivia, is historically dominated by houses and three to five storey buildings. The geology in and around the city is such that even very light buildings need to be supported on piles. The recent increase of the Bolivian economy, notably that of Santa Cruz, has created a demand for new residential as well as office and industrial buildings, which mostly consist of multi-storey or high-rise buildings with significantly larger foundation loads. Foundation piles have become larger and longer, and the load on individual piles is increased. The development has resulted in an increase in the demand for more sophisticated design and construction methods and stricter approach to verifying the quality of the construction processes and results. This paper describes to geology of the Santa Cruz region and how the geotechnical conditions are considered in the design and construction of piled foundations. The improvement of past construction and design techniques, based ...
This paper describes the results of the tip post-grouting that was performed to improve the nomin... more This paper describes the results of the tip post-grouting that was performed to improve the nominal axial resistance of 34 bored piles for the Urubo Bridge project crossing the Pirai River in Santa Cruz, Bolivia. A Smart Cell is a closed-type tip post-grouting device that is attached to the bottom of the steel reinforcement cage of a bored pile to premobilize end resistance and reduce uncertainty. Control of the grout is maintained within the device during injection and a uniform stress is imparted across entire base area simultaneously, inducing a pre-mobilization load into the pile as well as the soil. The induced load is computed directly from the grout pressure and known geometry of the device. During the grouting process, there were noticeable differences in the grouting pressures achieved and responses observed, even within short distances between the piles, which were likely caused by the highly variable soil conditions, composition, alterations during construction and engine...
Smart and Green Solutions for Civil Infrastructures Incorporating Geological and Geotechnical Aspects, 2021
To support column footings, slabs, elevator shafts, and shear walls for the World Trade Center bu... more To support column footings, slabs, elevator shafts, and shear walls for the World Trade Center building in Santa Cruz, Bolivia, about 350 full-displacement bored piles (FDPs) were designed and installed for an unfactored load of 255 tonne (2,500 kN). The piles were outfitted with an Expander Body (EB) to improve the axial bearing. The borehole diameter of each pile was about 500 mm and the EB was sized to be able to expand to maximum diameter of about 800 mm. A static head-down axial compression loading test was performed to evaluate the axial resistance and load-displacement response of the FDP+EB system. The test results showed that equipping an FDP pile with an EB significantly improved the bearing and enabled the FDP+EB pile to be considerably shortened—from 39 m to 29 m. The shortening of the piles saved the project about 25% in pile construction costs and about 40% in construction time. This paper provides an overview of the EB system and design methodology, summarizes the con...
The Expander Body (EB) technology has been used successfully to increase the pile toe capacity of... more The Expander Body (EB) technology has been used successfully to increase the pile toe capacity of bored piles in loose to medium dense soil. An important advantage of the EB system is the ability to monitor the EB expansion process, which provides important information regarding soil strength and soil stiffness. This information, obtained for each installed pile, can be used to determine the actual shape and pile toe area. The expansion pressure can be used to design the pile base capacity. The Expander Body system has been recently improved by incorporating the possibility of postgrouting of the soil below the expanded pile toe. This improvement measure provides additional strength and stiffness to the pile toe and reduces pile settlement. The shaft bearing capacity of bored piles can be increased by using a soil displacement auger, which avoids soil decompression and increases lateral soil stress. This paper describes the principle of the EB system. During the past 20 years, a lar...
Static response of a group of 13 piles tested simultaneously, 2019
Static loading tests to plunging "failure" were performed on a single pile and a group of 13 pile... more Static loading tests to plunging "failure" were performed on a single pile and a group of 13 piles in a loose to compact silty sand. The piles were 300-mm diameter, 9.5 m long, pressure-grouted, bored piles with an expanded pile toe, a 400 mm wide Expander Body (EBI). Each pile had a bidirectional cell placed just above the EBI at 8.3 m depth. The tests comprised a bidirectional test on the piles with the pile group cells activated via a common pressure pump, thus, ensuring that equal load was applied to all piles, allowing each pile to move individually. The pile group responded as a pier with shaft resistance acting mostly along the perimeter piles or along the pier circumference rather than as 13 single piles. A rigid cap was then constructed over the piles and a head-down test performed. Also in the head-down test, the developed resistance was mainly from the perimeter piles.
La presente investigación tuvo por objetivo el análisis teórico y práctico de la tecnología Expan... more La presente investigación tuvo por objetivo el análisis teórico y práctico de la tecnología Expander Body (EB), con la finalidad de conseguir al menos los siguientes resultados: -Correlaciones entre los parámetros obtenidos en los estudios geotécnicos y los valores de presión de inyección de los Expander Bodies ( lo que implica conocer su capacidad ). -Cuantificar la mejora en la capacidad portante de pilotes de distintos tipos en los que se incorpora la tecnología Expander Body. Para esto se han realizado diversas campañas de ensayos de carga en las que se comparó pilotes construidos con tecnologías iguales pero con la incorporación de Expander Bodies en unos elemento y no en otros -Mostrar diferentes aplicaciones prácticas en las que el uso de esta tecnología ha producido economías significativas con un alto control de calidad. -Mostrar la adaptación realizada en Bolivia a la tecnología original sueca
RESUMEN Durante el mes de Mayo del año 2013, con fines de investigación, se realizó la construcci... more RESUMEN Durante el mes de Mayo del año 2013, con fines de investigación, se realizó la construcción in situ de cuatro pilotes mediante distintas técnicas. Dos pilotes fueron construidos mediante el sistema de perforación a rotación con circulación de lodo bentonítico, uno de ellos con un cuerpo expandible (Expander Body) en la punta y una celda Osterberg. Los otros dos pilotes fueron instalados mediante el sistema de desplazamiento total (Full Displacement Pile-FDP). Los datos experimentales fueron obtenidos mediante el uso de strain gauges de cuerda vibrante y cables térmicos para evaluación de la integridad de los pilote. Previo a la construcción de los pilotes, se realizaron los trabajos de investigación geotécnica mediante 3 sondeos con ensayos SPT, 3 con ensayos CPTu y medición de ondas de corte. Posteriormente, se realizaron ensayos a carga estática, dinámica con grandes desplazamientos y un ensayo bidireccional mediante la celda Osterberg. En este trabajo se evalúa el comportamiento a carga axial de los pilotes construidos in situ utilizando los sistemas ya mencionados, mediante la interpretación de los registros de los ensayos de carga axial realizados y el uso de métodos analíticos y modelos numéricos desarrollados mediante elementos finitos. El comportamiento de cada uno de los pilotes es evaluado mediante el procesamiento y análisis información experimental, obteniendo: curvas de carga-desplazamiento en la cabeza del pilote, distribución de la carga en profundidad, capacidad de fuste y curvas de tensión de corte vs. desplazamiento (curvas t-z). Los resultados obtenidos durante los ensayos de carga estática (capacidad de carga y curva de carga-desplazamiento) son comparados con resultados obtenidos mediante modelos de elementos finitos. Se realiza una comparación con el objetivo de determinar si el uso de los métodos de diseño comúnmente utilizados en la práctica para pilotes excavados (métodos alfa y beta) e hincados (método de Nordlund para arenas), pueden ser utilizados para determinar la capacidad última de los pilotes construidos mediante sistemas de desplazamiento. Finalmente, se analiza el efecto que poseen los sistemas de expansión y FDP en las propiedades resistentes del suelo y en la capacidad de carga de un pilote frente a los pilotes construidos mediante la perforación convencional con lodo bentonítico.
Some criterion and conceptual basics about foundations for bridges are presented based on the act... more Some criterion and conceptual basics about foundations for bridges are presented based on the actual experience in Bolivia. Emphasis is made on the effect of the construction methods over the capacity of piles
Four strain-gage instrumented bored piles were constructed in a sedimentary, dense to very dense,... more Four strain-gage instrumented bored piles were constructed in a sedimentary, dense to very dense, fine to medium sand in Santa Cruz, Bolivia. Two of the test piles were the normally used bored pile constructed with bentonite slurry and two piles were Bauer Full Displacement Pile (FDP). One of each pair was equipped with the Expander Body, an inflatable steel cylinder that on pressure-grouting provides an enlarged pile toe. Head-down static loading test were performed on three of the piles and a bidirectional test was performed on the fourth pile, a standard pile with Expander Body and a bidirectional cell placed immediately above the EB. The latter pile was tested in 3 phases. First by activating the cell, second, by a head-down test, and, third, by a repeat bidirectional cell test. The static loading tests proved the shaft resistance of the FDP pile to be about twice that of the standard bored pile and that the Expander Body more than doubled the toe stiffness. The strain-gage records showed that the standard bored piles had multiple bulges and neckings, which affected the evaluation of the axial stiffness and load distribution of the piles. The testing programme was used for a prediction event with 60 persons, ahead of the tests, submitting predictions of the load-movement curves for the test piles and also a capacity appraised from the curves.
This video contents a general description of the EB technology with some practical details. This ... more This video contents a general description of the EB technology with some practical details. This technology is a step forward in QA/QC of deep foundations with remarkable savings in time and costs, beside the valuable geotechnical information obtained during the installation and expansion of each EB with cement grout. The record of volume and grout pressure plus the knowledge of the shape, allows to have a well known foundation element (pile or anchor)
The city of Santa Cruz, Bolivia, is historically dominated by houses and three to five storey bui... more The city of Santa Cruz, Bolivia, is historically dominated by houses and three to five storey buildings. The geology in and around the city is such that even very light buildings need to be supported on piles. The recent increase of the Bolivian economy, notably that of Santa Cruz, has created a demand for new residential as well as office and industrial buildings, which mostly consist of multi-storey or high-rise buildings with significantly larger foundation loads. Foundation piles have become larger and longer, and the load on individual piles is increased. The development has resulted in an increase in the demand for more sophisticated design and construction methods and stricter approach to verifying the quality of the construction processes and results. This paper describes to geology of the Santa Cruz region and how the geotechnical conditions are considered in the design and construction of piled foundations. The improvement of past construction and design techniques, based ...
This paper describes the results of the tip post-grouting that was performed to improve the nomin... more This paper describes the results of the tip post-grouting that was performed to improve the nominal axial resistance of 34 bored piles for the Urubo Bridge project crossing the Pirai River in Santa Cruz, Bolivia. A Smart Cell is a closed-type tip post-grouting device that is attached to the bottom of the steel reinforcement cage of a bored pile to premobilize end resistance and reduce uncertainty. Control of the grout is maintained within the device during injection and a uniform stress is imparted across entire base area simultaneously, inducing a pre-mobilization load into the pile as well as the soil. The induced load is computed directly from the grout pressure and known geometry of the device. During the grouting process, there were noticeable differences in the grouting pressures achieved and responses observed, even within short distances between the piles, which were likely caused by the highly variable soil conditions, composition, alterations during construction and engine...
Smart and Green Solutions for Civil Infrastructures Incorporating Geological and Geotechnical Aspects, 2021
To support column footings, slabs, elevator shafts, and shear walls for the World Trade Center bu... more To support column footings, slabs, elevator shafts, and shear walls for the World Trade Center building in Santa Cruz, Bolivia, about 350 full-displacement bored piles (FDPs) were designed and installed for an unfactored load of 255 tonne (2,500 kN). The piles were outfitted with an Expander Body (EB) to improve the axial bearing. The borehole diameter of each pile was about 500 mm and the EB was sized to be able to expand to maximum diameter of about 800 mm. A static head-down axial compression loading test was performed to evaluate the axial resistance and load-displacement response of the FDP+EB system. The test results showed that equipping an FDP pile with an EB significantly improved the bearing and enabled the FDP+EB pile to be considerably shortened—from 39 m to 29 m. The shortening of the piles saved the project about 25% in pile construction costs and about 40% in construction time. This paper provides an overview of the EB system and design methodology, summarizes the con...
The Expander Body (EB) technology has been used successfully to increase the pile toe capacity of... more The Expander Body (EB) technology has been used successfully to increase the pile toe capacity of bored piles in loose to medium dense soil. An important advantage of the EB system is the ability to monitor the EB expansion process, which provides important information regarding soil strength and soil stiffness. This information, obtained for each installed pile, can be used to determine the actual shape and pile toe area. The expansion pressure can be used to design the pile base capacity. The Expander Body system has been recently improved by incorporating the possibility of postgrouting of the soil below the expanded pile toe. This improvement measure provides additional strength and stiffness to the pile toe and reduces pile settlement. The shaft bearing capacity of bored piles can be increased by using a soil displacement auger, which avoids soil decompression and increases lateral soil stress. This paper describes the principle of the EB system. During the past 20 years, a lar...
Static response of a group of 13 piles tested simultaneously, 2019
Static loading tests to plunging "failure" were performed on a single pile and a group of 13 pile... more Static loading tests to plunging "failure" were performed on a single pile and a group of 13 piles in a loose to compact silty sand. The piles were 300-mm diameter, 9.5 m long, pressure-grouted, bored piles with an expanded pile toe, a 400 mm wide Expander Body (EBI). Each pile had a bidirectional cell placed just above the EBI at 8.3 m depth. The tests comprised a bidirectional test on the piles with the pile group cells activated via a common pressure pump, thus, ensuring that equal load was applied to all piles, allowing each pile to move individually. The pile group responded as a pier with shaft resistance acting mostly along the perimeter piles or along the pier circumference rather than as 13 single piles. A rigid cap was then constructed over the piles and a head-down test performed. Also in the head-down test, the developed resistance was mainly from the perimeter piles.
La presente investigación tuvo por objetivo el análisis teórico y práctico de la tecnología Expan... more La presente investigación tuvo por objetivo el análisis teórico y práctico de la tecnología Expander Body (EB), con la finalidad de conseguir al menos los siguientes resultados: -Correlaciones entre los parámetros obtenidos en los estudios geotécnicos y los valores de presión de inyección de los Expander Bodies ( lo que implica conocer su capacidad ). -Cuantificar la mejora en la capacidad portante de pilotes de distintos tipos en los que se incorpora la tecnología Expander Body. Para esto se han realizado diversas campañas de ensayos de carga en las que se comparó pilotes construidos con tecnologías iguales pero con la incorporación de Expander Bodies en unos elemento y no en otros -Mostrar diferentes aplicaciones prácticas en las que el uso de esta tecnología ha producido economías significativas con un alto control de calidad. -Mostrar la adaptación realizada en Bolivia a la tecnología original sueca
RESUMEN Durante el mes de Mayo del año 2013, con fines de investigación, se realizó la construcci... more RESUMEN Durante el mes de Mayo del año 2013, con fines de investigación, se realizó la construcción in situ de cuatro pilotes mediante distintas técnicas. Dos pilotes fueron construidos mediante el sistema de perforación a rotación con circulación de lodo bentonítico, uno de ellos con un cuerpo expandible (Expander Body) en la punta y una celda Osterberg. Los otros dos pilotes fueron instalados mediante el sistema de desplazamiento total (Full Displacement Pile-FDP). Los datos experimentales fueron obtenidos mediante el uso de strain gauges de cuerda vibrante y cables térmicos para evaluación de la integridad de los pilote. Previo a la construcción de los pilotes, se realizaron los trabajos de investigación geotécnica mediante 3 sondeos con ensayos SPT, 3 con ensayos CPTu y medición de ondas de corte. Posteriormente, se realizaron ensayos a carga estática, dinámica con grandes desplazamientos y un ensayo bidireccional mediante la celda Osterberg. En este trabajo se evalúa el comportamiento a carga axial de los pilotes construidos in situ utilizando los sistemas ya mencionados, mediante la interpretación de los registros de los ensayos de carga axial realizados y el uso de métodos analíticos y modelos numéricos desarrollados mediante elementos finitos. El comportamiento de cada uno de los pilotes es evaluado mediante el procesamiento y análisis información experimental, obteniendo: curvas de carga-desplazamiento en la cabeza del pilote, distribución de la carga en profundidad, capacidad de fuste y curvas de tensión de corte vs. desplazamiento (curvas t-z). Los resultados obtenidos durante los ensayos de carga estática (capacidad de carga y curva de carga-desplazamiento) son comparados con resultados obtenidos mediante modelos de elementos finitos. Se realiza una comparación con el objetivo de determinar si el uso de los métodos de diseño comúnmente utilizados en la práctica para pilotes excavados (métodos alfa y beta) e hincados (método de Nordlund para arenas), pueden ser utilizados para determinar la capacidad última de los pilotes construidos mediante sistemas de desplazamiento. Finalmente, se analiza el efecto que poseen los sistemas de expansión y FDP en las propiedades resistentes del suelo y en la capacidad de carga de un pilote frente a los pilotes construidos mediante la perforación convencional con lodo bentonítico.
Some criterion and conceptual basics about foundations for bridges are presented based on the act... more Some criterion and conceptual basics about foundations for bridges are presented based on the actual experience in Bolivia. Emphasis is made on the effect of the construction methods over the capacity of piles
Four strain-gage instrumented bored piles were constructed in a sedimentary, dense to very dense,... more Four strain-gage instrumented bored piles were constructed in a sedimentary, dense to very dense, fine to medium sand in Santa Cruz, Bolivia. Two of the test piles were the normally used bored pile constructed with bentonite slurry and two piles were Bauer Full Displacement Pile (FDP). One of each pair was equipped with the Expander Body, an inflatable steel cylinder that on pressure-grouting provides an enlarged pile toe. Head-down static loading test were performed on three of the piles and a bidirectional test was performed on the fourth pile, a standard pile with Expander Body and a bidirectional cell placed immediately above the EB. The latter pile was tested in 3 phases. First by activating the cell, second, by a head-down test, and, third, by a repeat bidirectional cell test. The static loading tests proved the shaft resistance of the FDP pile to be about twice that of the standard bored pile and that the Expander Body more than doubled the toe stiffness. The strain-gage records showed that the standard bored piles had multiple bulges and neckings, which affected the evaluation of the axial stiffness and load distribution of the piles. The testing programme was used for a prediction event with 60 persons, ahead of the tests, submitting predictions of the load-movement curves for the test piles and also a capacity appraised from the curves.
SE PRESENTAN LAS ADAPTACIONES Y MEJORAS QUE LA TECNOLOGIA EXPANDER BODY HA IDO TENIENDO A LO LARG... more SE PRESENTAN LAS ADAPTACIONES Y MEJORAS QUE LA TECNOLOGIA EXPANDER BODY HA IDO TENIENDO A LO LARGO DE LOS MÁS DE 20 AÑOS DE SU USO.
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-Correlaciones entre los parámetros obtenidos en los estudios geotécnicos y los valores de presión de inyección de los Expander Bodies ( lo que implica conocer su capacidad ). -Cuantificar la mejora en la capacidad portante de pilotes de distintos tipos en los que se incorpora la tecnología Expander Body. Para esto se han realizado diversas campañas de ensayos de carga en las que se comparó pilotes construidos con tecnologías iguales pero con la incorporación de Expander Bodies en unos elemento y no en otros
-Mostrar diferentes aplicaciones prácticas en las que el uso de esta tecnología ha producido economías significativas con un alto control de calidad. -Mostrar la adaptación realizada en Bolivia a la tecnología original sueca
Emphasis is made on the effect of the construction methods over the capacity of piles
fine to medium sand in Santa Cruz, Bolivia. Two of the test piles were the normally used bored pile
constructed with bentonite slurry and two piles were Bauer Full Displacement Pile (FDP). One of
each pair was equipped with the Expander Body, an inflatable steel cylinder that on pressure-grouting
provides an enlarged pile toe. Head-down static loading test were performed on three of the piles and
a bidirectional test was performed on the fourth pile, a standard pile with Expander Body and a
bidirectional cell placed immediately above the EB. The latter pile was tested in 3 phases. First by
activating the cell, second, by a head-down test, and, third, by a repeat bidirectional cell test. The
static loading tests proved the shaft resistance of the FDP pile to be about twice that of the standard
bored pile and that the Expander Body more than doubled the toe stiffness. The strain-gage records
showed that the standard bored piles had multiple bulges and neckings, which affected the evaluation
of the axial stiffness and load distribution of the piles. The testing programme was used for a
prediction event with 60 persons, ahead of the tests, submitting predictions of the load-movement
curves for the test piles and also a capacity appraised from the curves.
-Correlaciones entre los parámetros obtenidos en los estudios geotécnicos y los valores de presión de inyección de los Expander Bodies ( lo que implica conocer su capacidad ). -Cuantificar la mejora en la capacidad portante de pilotes de distintos tipos en los que se incorpora la tecnología Expander Body. Para esto se han realizado diversas campañas de ensayos de carga en las que se comparó pilotes construidos con tecnologías iguales pero con la incorporación de Expander Bodies en unos elemento y no en otros
-Mostrar diferentes aplicaciones prácticas en las que el uso de esta tecnología ha producido economías significativas con un alto control de calidad. -Mostrar la adaptación realizada en Bolivia a la tecnología original sueca
Emphasis is made on the effect of the construction methods over the capacity of piles
fine to medium sand in Santa Cruz, Bolivia. Two of the test piles were the normally used bored pile
constructed with bentonite slurry and two piles were Bauer Full Displacement Pile (FDP). One of
each pair was equipped with the Expander Body, an inflatable steel cylinder that on pressure-grouting
provides an enlarged pile toe. Head-down static loading test were performed on three of the piles and
a bidirectional test was performed on the fourth pile, a standard pile with Expander Body and a
bidirectional cell placed immediately above the EB. The latter pile was tested in 3 phases. First by
activating the cell, second, by a head-down test, and, third, by a repeat bidirectional cell test. The
static loading tests proved the shaft resistance of the FDP pile to be about twice that of the standard
bored pile and that the Expander Body more than doubled the toe stiffness. The strain-gage records
showed that the standard bored piles had multiple bulges and neckings, which affected the evaluation
of the axial stiffness and load distribution of the piles. The testing programme was used for a
prediction event with 60 persons, ahead of the tests, submitting predictions of the load-movement
curves for the test piles and also a capacity appraised from the curves.