Barrette Piles Research Articles

Evaluation of side and tip resistances for barrette piles using CYCU/Barrette/Side&Tip/64

This study focuses on evaluating the side and tip resistances for barrette piles under compression loading. An extensive dataset from field load tests, designated as CYCU/Barrette/Side&Tip/64, was utilized for analysis. These data were categorized into drained and undrained soils, based on the predominant soil conditions along the pile shaft. In contrast, tip resistance depended on the soil (drained or undrained) or rock condition at the pile tip. Eight interpretation methods were employed to evaluate the measured side and tip resistances of each load test. The predicted side resistance was calculated using the classical α and β methods developed for more common piles such as drilled shafts. For the prediction of tip resistance, end-bearing capacity models for a drilled shaft resting on soil or socketed in rock are considered. Subsequently, a comparison was made between the measured and predicted capacities. Based on these analyses, it was observed that the measured side resistance is the main contributor to the overall capacity of barrette piles. The percentage of measured side resistance ranges from around 80% to 90%. In addition, the predicted side resistance calculated using the α and β methods is smaller than the measured side resistance interpreted using the L2 criterion. To reduce this prediction bias, the adhesion factor (α) and stress factors (K/Ko) for barrette piles were adjusted. For the tip resistance, the trend is opposite – predicted values are larger than the measured values for barrette piles resting on soil or socketed in rock. Another approach to correct for prediction bias called the generalized model factor is presented.

Evaluation of Model Factors for Barrette Piles Based on CYCU/Barrette/64

Evaluation of Model Factors for Barrette Piles Based on CYCU/Barrette/64

Bidirectional static loading tests on barrette piles. A case history from Ho Chi Minh City, Vietnam

Bidirectional static loading tests were conducted on two strain-gage instrumented barrettes installed to 72 m depth in Ho Chi Minh City, Vietnam. The barrettes were to support a 16-storey building with 5 basements. The soil profile comprised layers of medium coarse to fine sand, medium clay, firm to stiff clayey soil, and dense sandy silt. The region is experiencing an ongoing land subsidence affecting the upper about 40 m of soil and, on average in the city, the ground surface is currently settling 16 mm/year. The test records were processed by means of effective stress analysis to provide the axial pile force distribution, load transfer functions, and equivalent head-down load–movement curve. The analysis was then used to obtain the equivalent pile-head load–movement response adjusted to the planned 22 m deep basement excavation. Load transfer functions were back-calculated from the test records and indicate that the construction will show somewhat large load-transfer movement. However, because the equilibrium plane will be below the subsiding layers, below 40 m depth, downdrag is not expected to affect the building. The load response of the barrettes is compared to the results of a bidirectional (BD) loading test on a 1.8 m diameter bored pile at an adjacent project.

Liquefaction and performance of foundation systems in Iskenderun during 2023 Kahramanmaras-Turkiye earthquake sequence

On February 6, 2023, two devastating earthquakes occurred on the East Anatolian Fault, Turkiye. The earthquakes had severe impacts on civil engineering structures in Iskenderun, Hatay. Reconnaissance studies were performed in Iskenderun to document and evaluate the performances of the different foundation systems and improved ground. Several soil liquefaction cases, including a boulevard, a mosque complex, fishing shelter, and military quarters were observed and documented along with the ground conditions and surface ejecta characteristics. The site observations during the reconnaissance study showed that the application of the unreinforced concrete piles was not a proper foundation solution against seismic loading and did not perform well. Whereas foundation systems including reinforced barrette piles and improved sites with jet grout columns were observed to perform quite well with negligible/no deformations. Observations at several structures indicate that conventional pile foundations also performed well, however structures built on deep foundation systems together with prior jet grout improved sites performed notably better.

Analysis of the influence of anchor piles on test results

The paper considers the main problems of design and calculation of deep foundations of high-rise buildings in the form of piles-barrettes. The results and methodology of field tests of barrette piles for the foundation of a 56-storey residential building in Moscow are presented. The characteristics of engineering-geological conditions of the future construction site and design solutions for pilot tests are presented. Given a large cross-section of the barrette, which involves a significant amount of pile-type soil mass with the formation of a complex stress-strain state, to obtain reliable results and verification of the calculated model is recommended to perform numerical tests in full compliance with the field experiment, taking into account the anchored piles. The paper describes the method and the results of the numerical calculation of the load-carrying capacity of a barrette taking into consideration the modeling of an anchoring system in the Midas GTS NX program complex by the finite-element method and shows the basic possibility of using the program complex and the described method for practical purposes with an admissible accuracy. The paper contains diagrams of vertical displacements of a barrette head as a function of the applied load in full-scale tests and a general evaluation of the carrying capacity of a barrette pile obtained by numerical solutions. It is found that by taking into account the anchoring system (beams and piles) in the numerical simulation, the calculation results obtained are the most accurate to the field tests in describing the behavior of the pile under load in comparison with the calculation of a single barrette pile. In spite of the fact that the barrette bottom is embedded into the rocky soils, the barrette piles are referred to the hanging piles according to the interaction conditions with the soil due to the significant load transfer along the lateral surface.

Use of a residential building’s foundation as Energy Geo-Structures: A case study in the Mediterranean environment

Geothermal energy, a type of renewable energy obtained from the Earth, can be used by Ground Source Heat Pumps (GSHPs) for space heating and cooling. GSHP systems extract/reject heat from/into the earth via a network of pipes or tubes known as Ground Heat Exchangers (GHEs),. GHEs can be horizontal or vertical and come in a variety of forms, including slinky loops and vertical spiral loops for horizontal configurations, and single U-tube, double U-tube in series or parallel, coaxial pipe, and spiral/helical pipe for vertical configurations. Although GSHPs exhibit a higher performance than conventional Air Source Heat Pumps (ASHPs), the systems are less appealing as investments due to their longer payback times and greater upfront costs. A competent design of the GSHP system with the appropriate GHE sizing, including the case of employing the GHEs in the structures foundations, can minimize the initial cost. Such structures are referred to as Thermo-Active Structure systems or Energy Geo-Structures (EGS), which have already found applications as energy piles, barrette piles, diaphragm walls, shallow foundations, retaining walls, embankments, and tunnel linings [1, 2, 3].
 Residential buildings in Cyprus have a higher cooling than heating demand, with an extended payback period for the investment, especially if the system is solely utilized for heating [4]. EGS coupled with a GSHP could offer a substitute to reduce the system’s initial expenses and make it more attractive as an investment. EGS have not yet seen applications in Cyprus, therefore an initial computational analysis utilizing the COMSOL software and relevant data is taken into consideration. To determine the heating and cooling loads, a three-bedroom, two-storey house with a total floor space of 190 m2, with nearly Zero Energy Building (nZEB) characteristics, is used as the typical case for a single detached residential building in Cyprus. The TRNSYS software was used to calculate the heating and cooling loads. In order to analyze the rejected/absorbed energy from the earth, typical foundations were constructed as full sized models in COMSOL (Figure 1). With the exception of pipes, where a 1D solution is employed, the convection diffusion equation for heat transfer is utilized with 3D conservation of heat transfer for an incompressible fluid. A detailed methodology can be found in Aresti et al. [5].
 For the COMSOL compuations, the site ground temperature characteristics and the local ambient temperature were taken into account. Based on the provided loads, the inlet and outlet temperatures were hourly calculated for the highest demand months: February for winter – heating, and July for summer – cooling.
 To assess the potential of using the foundation bed as an alternative to energy piles, a comparison on the performance of the two cases is presented in Figure 2 for both summer and winter conditions. The foundation bed is seen to work in a steady manner, which is highly desired in a system. However, it performs less well, with a lower COP than the energy piles system, which exhibits greater COP values than the foundation bed system both in winter and summer. It remains that both systems exhibit high enough COPs and nearly steady conditions. The COPs vary between 4.4 and 4.8. A yearly simulation (not shown here) yielded a lowest COP value of 4.5.
 The systems were also assessed economically by being compared to a convectional ASHP system. The economic study demonstrated that the suggested foundation systems had relatively short payback times, making them a plausible alternative. More detailed discussion on the results can be found in Aresti et al. [5]. As a future objective, an environmental and Life Cycle Analysis investigation, similar to the one performed by Aresti et al. [6], could provide a deeper insight of the plausibility of using the building foundation as EGS.

Foundation design of single-span arch bridges in China

Arch bridges have been constructed in China more than 1400 years ago. This study collated the details of 120 single-span arch bridges with spans of more than 100 m that have been constructed or undergoing construction in China over the recent three decades. The type proportion, span to rise ratio, spatial distribution, and span length of the 120 arch bridges were reported in this paper. An examination of the foundation of the 120 single-span arch bridges was further conducted. Based on the analysis of the arch bridge foundations, it was found that the foundation types can be grouped into enlarged footing, pile foundation, composite foundation, and “others”. Thus, the application rate of various foundation types, characteristics of each foundation type, and development trend of arch bridge foundations were investigated and discussed. Finally, case studies of single-span arch bridge with composite foundations consisting of open caisson and shaft, and foundation with barrette piles were reviewed. The construction techniques, applicable conditions and resistance characteristics of various foundations were analyzed and evaluated. The case studies highlighted in this paper illustrated the advancement, innovation and development in foundation engineering of single-span arch bridges in China.

Effects of Shaft Grouting on the Bearing Behavior of Barrette Piles: A Case Study in Ho Chi Minh City

The shaft-grouted method has been applied on high-rise buildings in Ho Chi Minh City for the purpose of increasing the bearing capacity of barrette piles. The Exim Bank Building foundation, using two kinds of shaft-grouted barrette piles, was 65m (TP1) and 85m (TP2) in depth. To assess the bearing capacity, this project assembly used the O-cell tools installed at 49m depth below the pile head level. Shaft grouting was performed from -25m to the TP1 pile toe level and -65m to the TP2 pile toe level. This work is based on the data from the O-cell experiments at the construction site and the results of finite element simulation in Plaxis software. The effectiveness of shaft grouting was analyzed and the length and position of the ejector were evaluated and compared in order to find the best solution for applying shaft grouting with the aim to ensure safety and mitigate economic problems.

A new hyperbolic variation method for settlement analysis of axially loaded single friction piles

This study describes a new hyperbolic method based on load transfer method for settlement analysis of axially loaded single friction piles. The new method is obtained by examining 14 pile load tests. The examined test piles were loaded until the piles were failed, and they were chosen from friction piles having variable diameters from 0.6 to 2.0 m and located in different geographical regions. Twelve of these test piles were circular bored piles, and two of them were barrette piles. According to the proposed hyperbolic method, the load–settlement graph is divided into two parts, and the relationship between load and settlement is defined by using two different hyperbolic variations each corresponding to one of the parts. Results of the settlement analysis of the four test piles obtained from the new proposed method and the four from the different methods based on load transfer method are presented comparatively with each other and with the pile load test results. The results of the pile settlement analysis and those of the pile load tests demonstrate that the new hyperbolic method yields accurate results for the most bored friction piles. The load settlement plots obtained by the new method match appropriately with measured values. On the other hand, the results of the barrette piles obtained from the hyperbolic method do not show the proper fit like those of the bored piles, when they are compared to those of the other methods based on the load transfer method.

Compression load tests on bored and barrette piles founded in gravelly sediments

Compressive tests on piles socketed in gravelly sediments were conducted. Six bored piles and four barrette piles, with or without base grouting, were studied using back-analysis. A spline function was used to fit the measured data for pile load along the depth. Using the fitted spline function and assuming that behaviour at the pile–soil interface is hyperbolic, back-analysis was used to determine the model parameters by calibrating the design value of β (the product of the coefficient of horizontal soil stress and the value of the tangent of the effective angle of shearing resistance of the soil–shaft interface) and comparing the results of back-analysis and the measured data. The results of this comparison revealed that the results of back-analysis were sensitive to the measured data. A back-calculated β value that is, in general, larger than that found by current methods was obtained.

A Numerical Study on the Estimation Method of the Results of Static Pile Load Test Using the Results of Bi-directional Pile Load Test of Barrette Piles

A Numerical Study on the Estimation Method of the Results of Static Pile Load Test Using the Results of Bi-directional Pile Load Test of Barrette Piles

Influences of Earthquake Characteristics on Seismic Performance of Anchored Sheet Pile Quay with Barrette Piles

Chen, F.M.; Tan, H.M.; Chen, J., and Jiao, Z.B., 2018. Influences of Earthquake Characteristics on Seismic Performance of Anchored Sheet Pile Quay with Barrette Piles. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 701–705. Coconut Creek (Florida), ISSN 0749-0208.Earthquake waves generated along crustal faults propagate through the bedrock and the local site deposits, impacting on any structure such as coastal structures. Seismic waves acting on the foundation of a sheet pile quay cause an oscillatory motion of the quay structure, and the seismic dynamic effect and soil liquefaction can significantly affect the safety of port structures. This paper reports the dynamic behaviour of a new sheet pile quay structure under seismic loads by using finite element method, and the new anchored sheet pile quay with barrette piles is developed to satisfy the requirements of higher elevation of retained soils and smaller wall deflection in practice. Both EL-Centro wave and Kobe wave are adopted in simulation to analyze the effect of earthquake characteristics on seismic performances of structure. The numerical calculation results show that the barrette piles are still effective to carry lateral earth pressure under the earthquake loads, and the maximum bending moment of structure does not occur when earthquake acceleration reaches the peak value. With the increase of earthquake peak acceleration value, the dynamic responses of structure are all increased at different degrees, and the amplification of barrette pile bending moment is the largest. The amplification coefficients of structure response under the Kobe wave loads are greater than those under the EL-Centro wave with the same PGA value, which indicates besides the peak value of earthquake wave, the responses of structure were also affected by other earthquake characteristics, such as spectrum, wave energy density and wave total energy.

Field Testing of Anchored Diaphragm Quay Wall Supported Using Barrette Piles

A diaphragm quay wall anchored using barrette piles was constructed to increase retained soil elevation and reduce quay wall deflection. This article presents the long-term field-test results of the first practical application of the new structure. The performance of the structure is discussed in terms of the settlement, lateral deflection, bending moment, tensile force, and lateral earth pressure. The maximum lateral displacement was found to be approximately 0.23% of the wall height. The barrette piles exhibited the highest bending moment among the different structures, indicating that they can effectively bear lateral loads. The load-transfer mechanism of the barrette piles can be summarized as a combination of the blocking effect in carrying the horizontal earth pressure and the anchoring effect in carrying the loads from the quay wall through tie-rods. The increase in the spacing between the quay wall and the barrette piles leads to a reduction in the horizontal earth pressure at higher elevations of the structures. Compared to the measurement results, Coulomb’s earth pressure theory significantly overestimates the earth pressure acting on the quay wall. Moreover, the lateral deflection increment as a result of dredging activities is greater than that resulting from superstructure construction.

Evaluation of base grouting for the bearing behavior of barrette piles socketed in a gravel formation

A comprehensive analysis for the effects of base grouting on barrette piles was carried out based on six compressive load tests on piles located in a newly developed residential area of the Taipei basin. All piles were socketed for a length of 3 m into a gravel formation at a depth of more than 45 m below the ground surface; four of these were base-grouted using the high-pressure cleaning and grouting method. Based on the strains measured at several depths along the pile shaft, side friction t–z curves for various soil strata and end bearing q–w curves in gravels are deduced. Comparing the test results of piles with and without base grouting, the effects of base grouting can be quantitatively evaluated. It is concluded that the base grouting has almost no influence on the initial stiffness of the pile head response curve for such a long piles, but significantly increases the ultimate bearing capacity and plastic stiffness of the pile head response curve for such long piles when they experience a large pile head displacement.

Quality assurance of concrete foundation elements using an ultrasonic evaluation technique

�This paper presents the approach and results adopted in a proactive quality assurance testing technique which was used to inspect, in a non-destructive manner, the integrity and homogeneity of over 200 different in-situ cast concrete foundation elements (ie bored piles, concrete barrette piles and diaphragm wall panels) in various Hong Kong construction sites. The test results were obtained from both public and private buildings and civil engineering projects in Hong Kong. These results show the effectiveness of the use of the Cross-hole Sonic Logging (CSL) method in revealing the different kinds of defects (such as honeycombing, voids, soil inclusions etc.) found during the construction process which under other forms of testing would otherwise remain undiscovered.