scholarly journals Proposta de previsão da capacidade de carga à tração de estacas tipo hélice contínua em solos granulares

Author(s):  
Caio Cardoso Scipião ◽  
Alfran Sampaio Moura

Foundations projects must present security measures concerning the structural element and soil-structure system failure and acceptable displacements. In buildings it is very common to have foundations which are only subjected to compressive loads, however, in many of them, the foundations are submitted to uplifting forces, thus it is also necessary to verify the safety conditions regarding uplift capacity. In this context, this article evaluates the applicability of specific and non-specific methods for estimating the uplift bearing capacity of continuous flight auger piles in granular soils. In addition to that, a method was developed in order to estimate the ultimate uplift capacity of these pile types. In order to so, this research was based on 97 Standard Penetration Tests (SPT), and 12 continuous flight auger piles in granular soils subjected to the uplift forces. Among the evaluated literature methods, the specific method that presented the best agreement was Meyerhof and Adams (1968), and the non-specific one was Meyerhof (1953), both with approximately 65% higher values, in average, than the reference values and with great scatter. On the other hand, the developed method presented good agreement and lower scatter, establishing an alternative for the determination of uplift bearing capacity of continuous flight auger piles in granular soils.

Author(s):  
Mahmoud Ghazavi ◽  
Kazem Barkhordari ◽  
Hooman Dabirmanesh

This paper presents a finite element modeling for determination of bearing capacity of a suction caisson subjected to vertical uplift loading. The approach looks at the uplift capacity of the caisson considering a non-uniform cross sectional area to account for a geometry optimization. For this purpose, the numerical simulation is first verified using available data from other research work especially centrifuge data. Parametric studies are then performed to investigate the role of influencing factors including taper angel. The results show that the bearing capacity of caisson increases with increasing the taper angle.


Author(s):  
Quan Cao ◽  
Shuhua Gong ◽  
Peigang Li ◽  
Heng Wan ◽  
Daolai Cheng

2021 ◽  
Vol 147 (1) ◽  
pp. 04020086
Author(s):  
Vittorio Ranieri ◽  
Nicola Berloco ◽  
Donato D’Auria ◽  
Vincenzo Disalvo ◽  
Veronica Fedele ◽  
...  
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Author(s):  
O. Maistrenko ◽  
M. Petrushenko ◽  
S. Nikul ◽  
Y. Sinilo

The article analyzes the possible risks that can arise when firing artillery and rocket launches. The disadvantages of the method of calculating the protection zones are identified, which taking into account will reduce the likelihood of the occurrence of abnormal situations, which can lead to tragic consequences and damage to objects adjacent to the boundary of the testing ground. Additions to the procedure for determining the protection zones of the test site in the interests of RVIA are proposed and the specified, correct sizes of these zones are provided. Development of rocket troops and artillery (RTaA) of the Armed Forces (AF) of Ukraine is impossible without a permanent improvement and modernisation of types of armament and ammunition to them, development of the new artillery systems and their ground tests. During realization of ground tests of types of armament and military technique (WME) of RTaA firing of artillery and starting of rockets is accompanied by errors or wrong acts of WME attendant and personnel or extraneous persons, the consequences of that must be envisaged, and the risk of their origin is Analysis of the battle firing, including during realization of anti-terror operation and operation of the incorporated forces on east of Ukraine row of ground tests of standards of WME RTaA test if possibility of origin of nonpermanent near-accidents during application of armament of RtaA as a result of rejection of trajectory of flight of projectile (mines) by the direction and distance from the expected targets. Mostly it happens through untaking into account of maximal rejections of meteorological and ballistic terms of firing from tabular or errors in calculations, wrong acquisition of charge, error at aiming of fighting machines, cannons, mortars. There for practice of the battle firing needs taking into account of these errors, that will give an opportunity consider ably to promo test rength security at application of armament of RAaT during testing of standards of WME. Thus, in the article certainly and possible risks that can arise up during realization of firing of artillery and starting of rockets are analysed, related to the lacks of existent methodology of realization of calculations in relation to providing of safety measures during the tests of WME RtaA. Suggestions are brought in, in relation to the improvement of methodology of realization of calculations of sizes of protective zones, that unlike existing more in detail take into account maximal deviations of terms of firing from tabular values. These suggestions for providing of safety measures it will be allowed to decrease probability of origin of situations, that can result in tragic consequences and to causing of damages to the objects that fit closely to the limits of training field. Anoffer adding to the order of determination of protective zones and given specified sizes of the sezones have an important practical value at determination of possibilities of grounds and providing of safety of testing and battle firing (starting) of RtaA.


Geosciences ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 329
Author(s):  
Mahdi O. Karkush ◽  
Mahmood D. Ahmed ◽  
Ammar Abdul-Hassan Sheikha ◽  
Ayad Al-Rumaithi

The current study involves placing 135 boreholes drilled to a depth of 10 m below the existing ground level. Three standard penetration tests (SPT) are performed at depths of 1.5, 6, and 9.5 m for each borehole. To produce thematic maps with coordinates and depths for the bearing capacity variation of the soil, a numerical analysis was conducted using MATLAB software. Despite several-order interpolation polynomials being used to estimate the bearing capacity of soil, the first-order polynomial was the best among the other trials due to its simplicity and fast calculations. Additionally, the root mean squared error (RMSE) was almost the same for the all of the tried models. The results of the study can be summarized by the production of thematic maps showing the variation of the bearing capacity of the soil over the whole area of Al-Basrah city correlated with several depths. The bearing capacity of soil obtained from the suggested first-order polynomial matches well with those calculated from the results of SPTs with a deviation of ±30% at a 95% confidence interval.


1977 ◽  
Vol 60 (1) ◽  
pp. 56-59 ◽  
Author(s):  
Emil Weisenberg ◽  
Baruch Gershon ◽  
Judith Schoenberg

Abstract A rapid and specific method is described for the determination of microamounts of methyl, propyl, and butyl p-hydroxybenzoic esters (parabens) in pharmaceuticals and cosmetics. The method involves the direct extraction of parabens into benzene or chloroform followed by derivatization with phosphorochloridate. The diethyl phosphate ester derivatives are cleaned up on a Florisil minicolumn and finally measured by gas-liquid chromatography on 5% OV-210 on Gas-Chrom Q. A flame photometric detector or a KCl thermionic detector may be used. The concentration response was linear up to 40 ng parabens. The reproducibility and margin of error were tested with fortified samples. This method may be applied to the estimation of other phenol derivatives.


1986 ◽  
Vol 23 (2) ◽  
pp. 58-63 ◽  
Author(s):  
Yu. G. Trofimenkov ◽  
M. A. Minkin ◽  
V. I. Gvozdik

2011 ◽  
Vol 261-263 ◽  
pp. 989-993 ◽  
Author(s):  
Anuchit Uchaipichat ◽  
Ekachai Man Koksung

An experimental program of laboratory bearing tests was performed to characterize the bearing capacity of foundation on unsaturated granular soils. All tests were performed by pushing a circular rod on the surface of compacted sand specimens with different values of matric suction until failure. The test results show an increase in ultimate bearing capacity with increasing matric suction at low suction value but a decrease in that at high level of suction. The comparisons between the test results and simulations using the expressions proposed in this paper are presented and discussed. Good agreements are achieved for all testing values of suction.


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