Comportement d'un pieu bi-fonction, fondation et échangeur de chaleur

2003 ◽  
Vol 40 (2) ◽  
pp. 388-402 ◽  
Author(s):  
Lyesse Laloui ◽  
Matteo Moreni ◽  
Laurent Vulliet
Keyword(s):  
Heat Exchanger ◽  
Skin Friction ◽  
Mechanical Load ◽  
Relative Displacement ◽  
Loading Test ◽  
Mechanical Loads ◽  
Pipe System ◽  
Under Construction ◽  
Thermal Influence

The behaviour of a pile subjected to thermo-mechanical loads was studied in situ with the aim of quantifying the thermal influence on the bearing capacity of heat exchanger piles. To accomplish this, a pile situated in a building under construction was equipped with a pipe system to inject heat into it using a special heat pump. Load cells, deformation gauges, and thermometers were installed to evaluate the behaviour of the pile during seven tests with coupled thermo-mechanical loads. The temperature variations applied to the pile were of the order of 15°C and the mechanical load reached 1300 kN. The results permitted the quantification of three significant effects brought about by the temperature increase: (i) pile uplift, (ii) mobilization of skin friction due to the relative displacement of the pile with respect to the ground, (iii) additional load generated in the pile by constrained dilation.Key words: heat exchanger pile, in situ test, loading test, thermo-mechanical loads, mobilization of skin friction.

scholarly journals In situ mechanical and electrical characterization of composite-integrated thin film-supercapacitors

2018 ◽  
Vol 188 ◽  
pp. 01028
Author(s):  
Jan Petersen ◽  
Sebastian Geier ◽  
Peter Wierach ◽  
Martin Wiedemann
Keyword(s):  
Thin Film ◽  
Manufacturing Process ◽  
Mechanical Load ◽  
Bending Test ◽  
Electrical Performance ◽  
Transport Systems ◽  
Large Temperature ◽  
Energy Storage Devices ◽  
Mechanical Loads

Future transport systems will be powered more and more electrically. Generally the energy is stored in batteries. To reduce system weight and volume, multifunctional materials could be the answer. Therefore materials with the capability to store electric energy and to bear mechanical loads, need to be investigated to understand the effect of mechanical load on such structural integrated energy storage devices. In this work a thin film-supercapacitor is build up and integrated within a composite structure. The capacitor is developed to withstand the manufacturing process of a glass-fibre reinforced polymer and to carry mechanical loads, while simultaneously storing electrical energy. By using a supercapacitor housing, which is compatible to epoxy resin, a strong bonding is achieved, leading to a mechanical robust multifunctional composite. An electrolyte with large temperature window, low vapour pressure and the compatibility to a carbon based electrodes is chosen, to meet the requirement regarding the manufacturing process of the supercapacitor itself and the fibre reinforced composite. The composites with integrated thin film-supercapacitor as well as a set of reference samples are mechanically characterised in tensile and four-point bending test. In situ measurements are performed to investigate the influence of mechanical load on the electrical performance.

scholarly journals Tension causes structural unfolding of intracellular intermediate filaments

2020 ◽  
Author(s):  
Frederik Fleissner ◽  
Sachin Kumar ◽  
Noreen Klein ◽  
Daniel Wirth ◽  
Ravi Dhiman ◽  
...  
Keyword(s):  
Multivariate Data Analysis ◽  
Mammalian Cells ◽  
Structural Changes ◽  
Mechanical Load ◽  
Structural Response ◽  
Mechanical Tension ◽  
Mechanical Loads ◽  
Dynamics Simulations

AbstractIntermediate filament (IF) proteins are a class of proteins that constitute different filamentous structures in mammalian cells. As such, IF proteins are part of the load-bearing cytoskeleton and support the nuclear envelope. Molecular dynamics simulations have shown that IF proteins undergo secondary structural changes to compensate mechanical loads, which has been confirmed by experimental in vitro studies on IF hydrogels. However, the structural response of intracellular IF to mechanical load has yet to be elucidated in cellulo. Here, we use in situ nonlinear Raman imaging combined with multivariate data analysis to quantify the intracellular secondary structure of the IF cytoskeletal protein vimentin under different states of cellular tension. We find that cells under native cellular tension contain more unfolded vimentin than chemically or physically relaxed specimens. This indicates that unfolding of IF proteins occurs intracellularly when sufficient forces are applied, suggesting that IF structures act as local force sensors in the cell to mark locations under large mechanical tension.

Experiment Study on Bearing Capacity of Muddy Siltstone Foundation and its Application

2013 ◽  
Vol 838-841 ◽  
pp. 101-106
Author(s):  
Dong Sheng Yang
Keyword(s):  
Theoretical Analysis ◽  
Bearing Capacity ◽  
Skin Friction ◽  
Static Loading ◽  
Soft Rock ◽  
Single Pile ◽  
Experiment Study ◽  
Loading Test ◽  
Static Loading Test

Rock-socket cast-in-situ piles is a commonly used style of foundation, but theoretical analysis, experiments and test research of bearing capacity behavior about rock-socket piles in soft rock have not adapted to the requirement of engineering. The static loading test of single pile on a project in argillaceous and silt laminate, through which the skin friction and point bearing capacity were measured, the bearing capacity behavior of rock-socket cast-in-situ piles in soft rock was analyzed.

scholarly journals Downdrag Measurements on a 160-Ft Floating Pipe Test Pile in Marine Clay

1972 ◽  
Vol 9 (2) ◽  
pp. 127-136 ◽  
Author(s):  
M. Bozozuk
Keyword(s):  
Skin Friction ◽  
Compressive Load ◽  
Marine Clay ◽  
Positive Skin ◽  
Negative Skin Friction ◽  
Pore Pressures ◽  
Excess Pore Pressures ◽  
Test Pile ◽  
Excess Pore

Large negative skin friction loads were observed on a 160 ft (49 m) steel pipe test pile floating in marine clay. The test pile was driven, open-ended, on the centerline of a 30 ft (9 m) high granular approach fill on the Quebec Autoroute near Berthierville. Since the installation was made in 1966 the fill has settled 21 in. (53 cm), dragging the pile down with it. Negative skin friction acting along the upper surface of the pile was resisted by positive skin friction acting along the lower end as it penetrated the underlying clay. Under these conditions the pile compressed about [Formula: see text] (2 cm). Analysis of the axial strains indicated that a peak compressive load of 140 t developed at the inflection point between negative and positive skin friction 73 ft (22 m) below the top of the pile. Negative and positive skin friction acting on the upper surface of the pile exceeded the in situ shear strength and approached the drained strength of the soil where excess pore water pressures had dissipated. At the lower end where the positive excess pore pressures were high and relative movement between the pile and the soil was large, the positive skin friction approached the remoulded strength as measured with the field vane. Skin friction was increasing, however, as positive escess pore pressures dissipated.This paper shows that skin friction loads are related to the combination of (a) in situ horizontal effective stresses, (b) horizontal stresses due to embankment loads, and (c) horizontal stresses due to differential settlement of the fill.

scholarly journals Influence of Hydrogeochemistry on Tunnel Drainage in Evaporitic Formations: El Regajal Tunnel Case Study (Aranjuez, Spain)

2021 ◽  
Vol 13 (3) ◽  
pp. 1505
Author(s):  
Ignacio Menéndez Pidal ◽  
Jose Antonio Mancebo Piqueras ◽  
Eugenio Sanz Pérez ◽  
Clemente Sáenz Sanz
Keyword(s):  
High Speed ◽  
Civil Engineering ◽  
Saturation Index ◽  
The Subject ◽  
Under Construction ◽  
Underground Flow ◽  
Very High ◽  
Over Time

Many of the large number of underground works constructed or under construction in recent years are in unfavorable terrains facing unusual situations and construction conditions. This is the case of the subject under study in this paper: a tunnel excavated in evaporitic rocks that experienced significant karstification problems very quickly over time. As a result of this situation, the causes that may underlie this rapid karstification are investigated and a novel methodology is presented in civil engineering where the use of saturation indices for the different mineral specimens present has been crucial. The drainage of the rock massif of El Regajal (Madrid-Toledo, Spain, in the Madrid-Valencia high-speed train line) was studied and permitted the in-situ study of the hydrogeochemical evolution of water flow in the Miocene evaporitic materials of the Tajo Basin as a full-scale testing laboratory, that are conforms as a whole, a single aquifer. The work provides a novel methodology based on the calculation of activities through the hydrogeochemical study of water samples in different piezometers, estimating the saturation index of different saline materials and the dissolution capacity of the brine, which is surprisingly very high despite the high electrical conductivity. The circulating brine appears unsaturated with respect to thenardite, mirabilite, epsomite, glauberite, and halite. The alteration of the underground flow and the consequent renewal of the water of the aquifer by the infiltration water of rain and irrigation is the cause of the hydrogeochemical imbalance and the modification of the characteristics of the massif. These modifications include very important loss of material by dissolution, altering the resistance of the terrain and the increase of the porosity. Simultaneously, different expansive and recrystallization processes that decrease the porosity of the massif were identified in the present work. The hydrogeochemical study allows the evolution of these phenomena to be followed over time, and this, in turn, may facilitate the implementation of preventive works in civil engineering.

Brazilian aviation nowcasting system: current stage and some results

2021 ◽  
Author(s):  
Vinícius Almeida ◽  
Gutemberg França ◽  
Francisco Albuquerque Neto ◽  
Haroldo Campos Velho ◽  
Manoel Almeida ◽  
...  
Keyword(s):  
Rio De Janeiro ◽  
Remote Sensing Data ◽  
Weather Forecast ◽  
Weather Data ◽  
Vertical Acceleration ◽  
In Situ Data ◽  
Forecasting System ◽  
Under Construction ◽  
Convective Weather

<p>Emphasizes some aspects of the aviation forecasting system under construction for use by the integrated meteorological center (CIMAER) in Brazil. It consists of a set of hybrid models based on determinism and machine learning that use remote sensing data (such as lighting sensor, SODAR, satellite and soon RADAR), in situ data (from the surface weather station and radiosonde) and aircraft data (such as retransmission of aircraft weather data and vertical acceleration). The idea is to gradually operationalize the system to assist CIMAER´s meteorologists in generating their nowcasting, for example, of visibility, ceiling, turbulence, convective weather, ice, etc. with objectivity and precision. Some test results of the developed nowcasting models are highlighted as examples of nowcasting namely: a) visibility and ceiling up to 1h for Santos Dumont airport; b) 6-8h convective weather forecast for the Rio de Janeiro area and the São Paulo-Rio de Janeiro route. Finally, the steps in development and the futures are superficially covered.</p>

scholarly journals Characterizing marshland compressibility by an in-situ loading test: design and set-up of an experiment in the Venice Lagoon

2020 ◽  
Vol 382 ◽  
pp. 345-351
Author(s):  
Pietro Teatini ◽  
Cristina Da Lio ◽  
Luigi Tosi ◽  
Alessandro Bergamasco ◽  
Stefano Pasqual ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Sea Level ◽  
Scale Effects ◽  
Venice Lagoon ◽  
Depth Interval ◽  
Deformation Model ◽  
High Porosity ◽  
Loading Test ◽  
In Situ Conditions

Abstract. The fate of coastal marshlands in the near future will strongly depend on their capability to maintain their elevation above a rising mean sea level. Together with the deposition of inorganic sediments during high tides, organic soil production by halophytic vegetation, and organic matter decomposition, land subsidence due to natural soil compression is a major factor controlling the actual elevation of salt-marsh platforms. Due to their high porosity and compressibility, the marsh sedimentary body undergoes large compression because of the load of overlying more recent deposits. The characterization of the geotechnical properties of these deposits is therefore of paramount importance to quantify consolidation versus accretion and relative sea level rise. However, undisturbed sampling of this loose material is extremely challenging and lab tests on in-situ collected samples are not properly representative of in-situ conditions due to the scale effects in highly heterogeneous silty soils such as those of the Venice lagoon. To overcome this limitation, an in-situ loading test was carried out in the Lazzaretto Nuovo salt-marsh in the Venice Lagoon, Italy. The load is obtained by a number of plastic tanks that are filled with seawater, reaching a cumulative load of 40 kN applied on a 2.5×1.8 m2 surface. Specific instrumentations were deployed before positioning the tanks to measure soil vertical displacement at various depths below the load (0, 10, and 50 cm) and distances (0, 40, and 80 cm) from the load centre. Moreover, six pressure transducers were used to record overpressure dissipation over time. The collected datasets will be interpreted through a 3-D flow-deformation model that, once calibrated, provides reliable estimates of the compressibility values for each monitored depth interval.

scholarly journals Response of tapered piles in cohesionless soil based on model tests

2010 ◽  
Vol 40 ◽  
pp. 85-92 ◽  
Author(s):  
Suman Manandhar ◽  
Noriyuki Yasufuku ◽  
Kiyoshi Omine ◽  
Taizo Kobayashi
Keyword(s):  
Skin Friction ◽  
Model Tests ◽  
High Density ◽  
Cohesionless Soil ◽  
Cohesionless Soils ◽  
Loading Test ◽  
Tapered Pile ◽  
Different Types ◽  
Steel Piles ◽  
Settlement Ratio

This paper describes model tests of different types of tapered piles in cohesionless soils. Chromium plated three steel piles, one straight and two taper-shaped piles of same length and pile tip diameters have been executed for pile loading test in a downward frictional mode. Two different types of model grounds have been prepared for the test. Relative densities of 80 % and 60 % have been modeled to penetrate piles in two different types of sands to observe the effectiveness of skin frictions of different types of piles. The response of tapered piles has shown that the skin friction has increased with increasing the tapering angle at normalized settlement ratio of 0.4. High density ground yields higher skin friction when the maximum tapered pile was penetrated. Slightly increased tapering angle of the pile affects remarkably on the skin friction with compared to conventional straight cylindrical pile even at small 0.1 settlement ratios.

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