scholarly journals Field Tests of Deep Power-installed Screw Anchors in Permafrost

1974 ◽  
Vol 11 (3) ◽  
pp. 348-358 ◽  
Author(s):  
G. H. Johnston ◽  
B. Ladanyi
Keyword(s):  
Test Data ◽  
Creep Behavior ◽  
Load Capacity ◽  
Field Tests ◽  
Secondary Creep ◽  
Test Results ◽  
Test Program ◽  
Slip Surfaces

A test program was conducted in northern Manitoba to evaluate the creep behavior and load capacity of 8-, 10-, and 15-in. (20.3-, 25.4-, and 38.1-cm) diameter power-installed screw anchors embedded in permafrost (frozen, stratified silts and clays containing ice at about 31.5 °F (−0.3 °C)). The test results show that the anchors behaved under uplift loads, in a manner that was essentially very similar to that exhibited by deep footings of the same size. No failure planes (slip surfaces) were observed around the plates but a deformed zone above the plates was clearly visible in the varved soil when the anchors were excavated after testing. A method of analysis which allows the test data to be used directly for design, based on secondary creep rates and allowable displacements, is described.

scholarly journals ANALYSIS OF THE FIELD TESTS RESULTS OF BORED CONICAL PILES UNDER THE ACTION OF VARIOUS TYPES OF LOADS

2018 ◽  
Vol 3 (3) ◽  
pp. 24-29
Author(s):  
Ирина Рыбникова ◽  
Irina Rybnikova ◽  
Александр Рыбников ◽  
Aleksandr Rybnikov
Keyword(s):  
Bearing Capacity ◽  
Load Capacity ◽  
Normal Component ◽  
Cone Angle ◽  
Field Tests ◽  
Side Surface ◽  
Test Results ◽  
Head Diameter ◽  
Cylindrical Piles ◽  
Bored Piles

One of the methods of improving the bearing capacity of bored piles is giving them a taper. The feature of these (wedge-type) piles is that under load they work "as a thrust" and transfer part of the load due to the normal component to the inclined side surface. Three sizes of tapered bored piles were tested, with the length of 4.5 m, head diameter 0.4; 0.5; 0.6 m and with cone angle 1o and 2,5o. The test results were compared with the test results of cylindrical piles, 4.5 m long, with head diameter 0.4 m and 0.6 m. It has been discovered that with the increasing cone angle, the bearing capacity of piles against the pressing load, especially the specific load capacity for 1 m3 of material, as compared to cylindrical piles, increases significantly. It has been determined that the larger is the diameter of the head of the pile, the higher is the bearing capacity against the horizontal load, and the bearing capacity against the pullout load is equal to the breakout force of a pile from the soil.

Dynamic Performance Characteristics of Floating-Ring Bearings With Varied Oil-Injection Swirl-Control Angles

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Daniel Tamunodukobipi ◽  
Chang Ho Kim ◽  
Yong-Bok Lee
Keyword(s):  
Test Data ◽  
Hydrodynamic Instability ◽  
Load Capacity ◽  
Dynamic Performance ◽  
Efficient Solutions ◽  
Test Results ◽  
Clearance Ratio ◽  
Thermal Growth ◽  
Oil Injection ◽  
Sufficient Test

Hydrodynamic instability is a prime causative of performance irregularities and violent vibrations in floating-ring bearing (FRB) supported turbosystems. The quest for energy-efficient solutions to this has stimulated the development of diverse FRB design-geometries, dimensional relationships, and surface-contours. Unfortunately, these modifications are characterized mainly by model-predictors, which results lack sufficient test-data to benchmark their authenticities. This work presents the concept and the test-data of flow redirection in FRBs by using an oil-injection swirl-control mechanism (OISCM) to attenuate rotordynamic instabilities. FRBs with radius ratio = 1.75 and clearance ratio = 1.5 are tested for various OISCM angles (0 deg, 30 deg, and 60 deg) and under a specific load = 50 kN/m2. The test results indicate that FRBs with OISCM demonstrate substantial improvements in damping and stability characteristics. Their whirl-frequency-ratio (WFR) and cross-coupled forces are lower because of improved symmetry of films' pressure-forces (Kxx ≈ Kyy). Although the magnitudes of direct damping are higher (|Cxx| = 16.92 kN s/m for 60 deg and 6.03 kN s/m for 0 deg), the load capacity (Kxx) is slightly lower than the normal (0 deg), injection. Nonetheless, this discrepancy in load capacities becomes insignificant for speeds above 22 krpm. The WFR and subsynchronous amplitudes, which are graphic reflections of the bearing-based instability, become progressively smaller with increasing OISCM angle. However, this advantage at elevated speeds can only be sustained by a corresponding increase in oil-supply pressure to circumvent the advent of a starved inner-film and its attendant imbalance response and thermal growth. In closure, the OISCM bearing is more effective for mitigating rotordynamic instabilities in turborotors than conventional FRBs.

scholarly journals Predicting bending creep of laminated veneer lumber (LVL) sengon (Paraserianthes falcataria) beams from initial creep test data

2018 ◽  
Vol 195 ◽  
pp. 02028
Author(s):  
Achmad Basuki ◽  
Ali Awaludin ◽  
Bambang Suhendro ◽  
Suprapto Siswosukarto
Keyword(s):  
Test Data ◽  
Creep Test ◽  
Ultimate Load ◽  
Beam Deflection ◽  
Creep Model ◽  
Secondary Creep ◽  
Test Results ◽  
Creep Tests ◽  
Paraserianthes Falcataria ◽  
Laminated Veneer Lumber

This paper presents the results of creep tests of Laminated Veneer Lumber Sengon (LVL Sengon) beams, aiming to determine the creep factor and to establish the prediction beam deflection based on the initial creep test data. The LVL Sengon beams have a cross section of 40 mm by 80 mm and a clear span length of 2,000 mm, they were loaded at midspan for three different stress levels: 30%, 40%, and 50% of the ultimate load within 30, 60, and 90 days. Each loading level consists of four repetitive beams where one beam was wrapped with a plastic sheet. The test results showed that for 90 days the bending creep test can not determine the secondary creep yet. Curve fitting of bending creep test data indicated that the parameters of the Modified Burger creep model of the first 30 days can be accurately used to predict the beam deflection curve up to 60 and 90 days of loading.

Prediction of Pile Performance in Permafrost Under Lateral Load

1975 ◽  
Vol 12 (4) ◽  
pp. 510-523 ◽  
Author(s):  
R. K. Rowley ◽  
G. H. Watson ◽  
B. Ladanyi
Keyword(s):  
Test Data ◽  
Load Capacity ◽  
Field Tests ◽  
Theoretical Method ◽  
Steel Pipe ◽  
Subgrade Reaction ◽  
Creep Tests ◽  
Design Values ◽  
Pile Load Tests ◽  
Creep Modulus

In 1971 lateral pile tests were performed at Inuvik, N.W.T. to determine design values in creep for timber and steel pipe piles. Formulation of a theoretical method for prediction of pile load capacity from basic permafrost creep parameters was a part of this program.In 1972 pressuremeter creep tests were performed at the same site so that test pile performance could be predicted independently and compared with measured results. The pressuremeter tests made and the creep parameter values obtained, the predicted pile performance curves and the comparisons with actual test data are presented in this paper.A Menard pressuremeter was used to determine permafrost creep parameters at an average ground temperature of 29.2 °F (−1.6 °C). Values for the representative creep modulus and exponents for this soil were derived from the test data. These were used for calculating pressure–deflection curves and subgrade reaction moduli for the laterally loaded piles.To demonstrate the applicability of the theory, the subgrade reaction moduli derived from the pressuremeter tests were compared with those deduced directly from the pile load tests. A reasonable agreement was found with the subgrade reaction moduli values obtained for the timber piles. However, the steel pipe piles responded as though the modulus was much higher.The confirmation field tests were made at a site having ice-rich permafrost whose behavior approaches that of pure ice. To apply the basic theory generally, additional field confirmation tests would be needed, for example, in ice-poor permafrost and covering much longer periods of time.

Systematic Investigations on the Influence of Case Depth on the Pitting and Bending Strength of Case Carburized Gears

2003 ◽  
Author(s):  
B.-R. Ho¨hn ◽  
P. Oster ◽  
T. Tobie
Keyword(s):  
Bending Strength ◽  
Load Capacity ◽  
Influence Factors ◽  
Maximum Load ◽  
Hardened Layer ◽  
Case Depth ◽  
Test Results ◽  
Test Program ◽  
Extensive Test ◽  
Gear Geometry

The influence of case depth on the pitting and bending strength of case carburized gears was investigated. For this purpose an extensive test program on gears of different sizes, different gear geometry and with systematically varied case depth has been carried out. Residual stresses and further characteristics of the case hardened layer — that are influenced by the value of case depth as well — are examined. Based on the test results, rating formulas are derived to calculate the optimum case depth for maximum load capacity. Influence factors are defined, by which the influence of case depth on the load capacity regarding pitting and bending strength can be taken into consideration if rating a gear according to the standardized calculation method of DIN 3990/ISO 6336.

Pemberian Umpan Balik Dalam Meningkatkan Hasil Belajar dan Minat Belajar Mahasiswa

2015 ◽  
Vol 4 (3) ◽  
Author(s):  
Seruni Seruni ◽  
Nurul Hikmah
Keyword(s):  
Information Technology ◽  
Learning Outcomes ◽  
Test Data ◽  
Random Sampling ◽  
Covariance Matrices ◽  
Test Results ◽  
Immediate Feedback ◽  
Statistics Course ◽  
Independent Variable ◽  
Descriptive Statistical Analysis

<p>The purpose of this study is to find and analyze the effect of feedback on <br />learning outcomes in mathematics and an interest in basic statistics course. The <br />population in this study are affordable Information Technology Student cademic Year 2012/2013 Semester II Indraprasta PGRI University of South Jakarta. Sample The study sample was obtained through random sampling. This study used an experimental method to the analysis using the MANOVA test. This study has three variables, consisting of: one independent variable, namely the provision of feedback (immediate and delayed), and two dependent variable is the result of interest in the study of mathematics and basic statistics course. The data was collected for the test results to learn mathematics, and a questionnaire for the interest in basic statistics course. Collected data were analyzed using the MANOVA test. Before the data were analyzed, first performed descriptive statistical analysis and test data analysis requirements (test data normality and homogeneity of covariance matrices). The results show that the learning outcomes of interest in mathematics and basic statistics course for students who are given immediate feedback higher than students given feedback delayed. <br /><br /></p>

scholarly journals Estimation of Outdoor PM2.5 Infiltration into Multifamily Homes Depending on Building Characteristics Using Regression Models

2021 ◽  
Vol 13 (10) ◽  
pp. 5708
Author(s):  
Bo-Ram Park ◽  
Ye-Seul Eom ◽  
Dong-Hee Choi ◽  
Dong-Hwa Kang
Keyword(s):  
Regression Analysis ◽  
Correlation Analysis ◽  
Field Test ◽  
Outer Surface ◽  
Regression Models ◽  
Field Tests ◽  
Test Results ◽  
Correlation And Regression Analysis ◽  
Building Characteristics ◽  
Pm2.5 Concentration

The purpose of this study was to evaluate outdoor PM2.5 infiltration into multifamily homes according to the building characteristics using regression models. Field test results from 23 multifamily homes were analyzed to investigate the infiltration factor and building characteristics including floor area, volume, outer surface area, building age, and airtightness. Correlation and regression analysis were then conducted to identify the building factor that is most strongly associated with the infiltration of outdoor PM2.5. The field tests revealed that the average PM2.5 infiltration factor was 0.71 (±0.19). The correlation analysis of the building characteristics and PM2.5 infiltration factor revealed that building airtightness metrics (ACH50, ELA/FA, and NL) had a statistically significant (p < 0.05) positive correlation (r = 0.70, 0.69, and 0.68, respectively) with the infiltration factor. Following the correlation analysis, a regression model for predicting PM2.5 infiltration based on the ACH50 airtightness index was proposed. The study confirmed that the outdoor-origin PM2.5 concentration in highly leaky units could be up to 1.59 times higher than that in airtight units.

Measurements of Rotordynamic Coefficients of Hybrid Bearings With (a) a Plugged Orifice, and (b) a Worn Land Surface

2002 ◽  
Vol 124 (2) ◽  
pp. 363-368 ◽  
Author(s):  
F. Laurant ◽  
D. W. Childs
Keyword(s):  
Test Data ◽  
Land Surface ◽  
Rocket Engine ◽  
Liquid Rocket Engine ◽  
Test Results ◽  
Rotordynamic Coefficients ◽  
Hybrid Bearing ◽  
Liquid Rocket

Test results are presented for the rotordynamic coefficients of a hybrid bearing that is representative of bearings for liquid-rocket-engine turbopump applications. The bearing is tested in the following two degraded conditions: (a) one of five orifices plugged, and (b) a locally enlarged clearance to simulate a worn condition. Test data are presented at 24,600 rpm, with supply pressures of 4.0, 5.5, and 7.0 MPa, and eccentricity ratios from 0.1 to 0.5 in 0.1 increments. Overall, the results suggest that neither a single plugged orifice nor significant wear on the bearing land will “disable” a well-designed hybrid bearing. These results do not speak to multiple plugged orifices and are not an endorsement for operations without filters to prevent plugging orifices.

Field Tests of Guide Vanes and Runner Blades of a Large Bulb Turbine for Output Deficiency Diagnosis

2012 ◽  
Vol 212-213 ◽  
pp. 1057-1061 ◽  
Author(s):  
Zhong Liu ◽  
Zhu Qing Huang ◽  
Shu Yun Zou ◽  
Hong De Rao
Keyword(s):  
Field Tests ◽  
Economic Loss ◽  
Hydropower Plant ◽  
Test Results ◽  
Guide Vanes ◽  
Factors Affecting ◽  
Runner Blade ◽  
Main Factors ◽  
Theoretical Analyses ◽  
Bulb Turbine

The 3# bulb turbine in Hongjiang Hydropower Plant has faced the problem of output deficiency since its commission in Sept. 2003, which caused a large economic loss. Following simple theoretical analyses on the main factors affecting the turbine’s output and efficiency, the field test schemes were determined to measure the shapes and intervals of guide vanes and runner blades of the 3#, 5# and 6# turbines. The test results discover that the average blade intervals of the 3# turbine are generally less than those of the 5# one. Suggestions on runner blade installation adjustment and combined curve modification are given.

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