Rigid latticed steel frames: two large-scale tests and failure predictions

1987 ◽  
Vol 14 (5) ◽  
pp. 602-613 ◽  
Author(s):  
John S. Ellis
Keyword(s):  
Cross Section ◽  
Large Scale ◽  
Static Load ◽  
Yield Criterion ◽  
Elastic Stiffness ◽  
Free Standing ◽  
Stiffness Matrices ◽  
Failure Loads ◽  
Uniform Cross Section ◽  
Large Scale Tests

This work is concerned with the predictions of failure under static load for two identical free-standing latticed cantilever frames. Each structure was 3 m high and consisted of three storeys with panel points 1 m apart; in plan it was 1 m2; its diagonals were at 45° in the form of St. Andrew's cross; all joints were welded and were considered rigid. The four bases were bolted to the laboratory floor and the static load was applied at the top as two compressive horizontal forces parallel to the sides of the structure. The individual members were all solid mild steel round rods; the verticals were of uniform cross section of 25.4 mm in diameter with a slenderness of 157; the horizontal cross-arms were of uniform cross section of 19 mm in diameter; and the diagonals were of uniform cross section of 15.9 mm in diameter. The diagonals were cut at their mid-lengths and welded to give a flush joint.The total horizontal loads that caused failure of the two structures were 79.6 and 79.2 kN. In both cases failure occurred by the sudden buckling of one of the bottom-storey vertical legs, inwards towards the centre of the structure. Also upon failure, the diagonals in the bottom storey of the compression face buckled inwards and the compression diagonal of the side contiguous to the buckled leg also buckled.Three elastic stiffness matrices were used to predict the failure loads: (1) linear with yield criterion, 116 kN; (2) stability with change in sign of the total potential energy, 66 kN; and (3) bowing with the criterion of maximum curvature of the load–deflection curve, 80 kN. The failure loads of the two structures were thus accurately predicted by the bowing matrix. Key words: latticed rigid frames, large-scale tests, bowing matrix, steel.

Magat Dams: Design of internal filters and drains

1983 ◽  
Vol 20 (3) ◽  
pp. 491-501 ◽  
Author(s):  
Sydney F. Hillis ◽  
E. Glen Truscott
Keyword(s):  
Cross Section ◽  
Large Scale ◽  
Filter Design ◽  
The Philippines ◽  
Core Material ◽  
Project Area ◽  
Intact Core ◽  
Dam Core ◽  
Large Scale Tests ◽  
Design And Testing

This paper describes the design and testing for the filter and drain zones for the Magat Dams. These four rockfill structures are located in the Philippines and range in height from 25 to 115 m. Construction was completed in late 1982. The project area is in a seismically active region and, as a result, the dam design had to be inherently conservative. This resulted in a highly zoned cross section and the provision of several wide filter and drain zones. The design of the filters and drains were checked by a series of large scale tests involving a 580 mm diam. permeameter and a large flume. Owing to the risk, however slight, of the dam cores being cracked during a major earthquake, the tests were carried out using both intact core material and core material into which a crack had been introduced. The results of the testing indicate that: (a) the filter gradations chosen are satisfactory, (b) it was prudent at Magat to introduce two filter zones between the dam core and the chimney drain, (c) conventional filter criteria are overly conservative when applied to the Magat core material, and (d) conventional criteria do not apply to the case of a cracked core. In this case the protective filter should contain a small amount of noncohesive fines. This is in accordance with developing practice. Keywords: filter design, testing, dam design, seismic effects, cracking.

Axial capacity of tapered piles established from model tests

1999 ◽  
Vol 36 (6) ◽  
pp. 1185-1194 ◽  
Author(s):  
M Hesham El Naggar ◽  
Jin Qi Wei
Keyword(s):  
Cross Section ◽  
Large Scale ◽  
Load Transfer ◽  
Design Procedure ◽  
Experimental Results ◽  
Unit Load ◽  
Axial Capacity ◽  
Laboratory Setup ◽  
Standard Design ◽  
Uniform Cross Section

Tapered piles represent a more efficient distribution of pile material than uniform cross section piles in several respects. An extensive experimental research program was conducted to study the efficiency of tapered piles compared with piles of uniform cross section with the same material input. Three instrumented model steel piles with different degrees of taper were used in this program. The piles were tested in a large-scale laboratory setup under compressive and tensile loads. The pile head load and displacement and the strain along the piles were measured simultaneously. The objectives of the present paper were twofold: to examine the validity of the experimental results, and to use the unit load transfer curves established from the experimental results to predict the bearing capacity of prototype tapered piles. The shaft resistance for straight-sided wall piles established from the experimental results compared well with the theoretical predictions using the standard design procedure. The beneficial effect of pile taper was significant up to a depth of 20 pile diameters. The negative effect of the pile taper on the uplift capacity diminished quickly with depth and hence the performance of actual tapered piles (with greater length) would be comparable to that of straight-sided wall piles.

Soil/Tire Interaction Analysis Using FEM and FVM

2005 ◽  
Vol 33 (1) ◽  
pp. 38-62 ◽  
Author(s):  
S. Oida ◽  
E. Seta ◽  
H. Heguri ◽  
K. Kato
Keyword(s):  
Large Scale ◽  
Interaction Analysis ◽  
Yield Criterion ◽  
Surrounding Medium ◽  
Flow Analysis ◽  
Measurement Data ◽  
Traction Force ◽  
Elastoplastic Material ◽  
The Road ◽  
Soil Flow

Abstract Vehicles, such as an agricultural tractor, construction vehicle, mobile machinery, and 4-wheel drive vehicle, are often operated on unpaved ground. In many cases, the ground is deformable; therefore, the deformation should be taken into consideration in order to assess the off-the-road performance of a tire. Recent progress in computational mechanics enabled us to simulate the large scale coupling problem, in which the deformation of tire structure and of surrounding medium can be interactively considered. Using this technology, hydroplaning phenomena and tire traction on snow have been predicted. In this paper, the simulation methodology of tire/soil coupling problems is developed for pneumatic tires of arbitrary tread patterns. The Finite Element Method (FEM) and the Finite Volume Method (FVM) are used for structural and for soil-flow analysis, respectively. The soil is modeled as an elastoplastic material with a specified yield criterion and a nonlinear elasticity. The material constants are referred to measurement data, so that the cone penetration resistance and the shear resistance are represented. Finally, the traction force of the tire in a cultivated field is predicted, and a good correlation with experiments is obtained.

Stratigraphic Architecture of a Fluvial-lacustrine Basin-fill Succession at Desolation Canyon, Uinta Basin, Utah: Reference to Walthers’ Law and Implications for the Petroleum Industry

2016 ◽  
Vol 53 (1) ◽  
pp. 5-28 ◽  
Author(s):  
Grace Ford ◽  
David Pyles ◽  
Marieke Dechesne
Keyword(s):  
Cross Section ◽  
Oil Shale ◽  
Large Scale ◽  
Green River Formation ◽  
Sand Content ◽  
Fluvial System ◽  
Uinta Basin ◽  
Green River ◽  
Lacustrine Basin ◽  
Basin Fill

A continuous window into the fluvial-lacustrine basin-fill succession of the Uinta Basin is exposed along a 48-mile (77-kilometer) transect up the modern Green River from Three Fords to Sand Wash in Desolation Canyon, Utah. In ascending order the stratigraphic units are: 1) Flagstaff Limestone, 2) lower Wasatch member of the Wasatch Formation, 3) middle Wasatch member of the Wasatch Formation, 4) upper Wasatch member of the Wasatch Formation, 5) Uteland Butte member of the lower Green River Formation, 6) lower Green River Formation, 7) Renegade Tongue of the lower Green River Formation, 8) middle Green River Formation, and 9) the Mahogany oil shale zone marking the boundary between the middle and upper Green River Formations. This article uses regional field mapping, geologic maps, photographs, and descriptions of the stratigraphic unit including: 1) bounding surfaces, 2) key upward stratigraphic characteristics within the unit, and 3) longitudinal changes along the river transect. This information is used to create a north-south cross section through the basin-fill succession and a detailed geologic map of Desolation Canyon. The cross section documents stratigraphic relationships previously unreported and contrasts with earlier interpretations in two ways: 1) abrupt upward shifts in the stratigraphy documented herein, contrast with the gradual interfingering relationships proposed by Ryder et al., (1976) and Fouch et al., (1994), 2) we document fluvial deposits of the lower and middle Wasatch to be distinct and more widespread than previously recognized. In addition, we document that the Uteland Butte member of the lower Green River Formation was deposited in a lacustrine environment in Desolation Canyon. Two large-scale (member-scale) upward patterns are noted: Waltherian, and non-Waltherian. The upward successions in Waltherian progressions record progradation or retrogradation of a linked fluvial-lacustrine system across the area; whereas the upward successions in non-Waltherian progressions record large-scale changes in the depositional system that are not related to progradation or retrogradation of the ancient lacustrine shoreline. Four Waltherian progressions are noted: 1) the Flagstaff Limestone to lower Wasatch Formation member records the upward transition from lacustrine to fluvial—or shallowing-upward succession; 2) the upper Wasatch to Uteland Butte records the upward transition from fluvial to lacustrine—or a deepening upward succession; 3) the Uteland Butte to Renegade Tongue records the upward transition from lacustrine to fluvial—a shallowing-upward succession; and 4) the Renegade Tongue to Mahogany oil shale interval records the upward transition from fluvial to lacustrine—a deepening upward succession. The two non-Waltherian progressions in the study area are: 1) the lower to middle Wasatch, which records the abrupt shift from low to high net-sand content fluvial system, and 2) the middle to upper Wasatch, which records the abrupt shift from high to intermediate net-sand content fluvial system.

scholarly journals Thermoelectric Properties of Thin Films from Sorted Single-Walled Carbon Nanotubes

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3808 ◽  
Author(s):  
Blazej Podlesny ◽  
Bogumila Kumanek ◽  
Angana Borah ◽  
Ryohei Yamaguchi ◽  
Tomohiro Shiraki ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Thermoelectric Properties ◽  
Large Scale ◽  
Single Walled Carbon Nanotubes ◽  
Parent Material ◽  
Free Standing ◽  
Two Phase ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes ◽  
Aqueous Two Phase Extraction

Single-walled carbon nanotubes (SWCNTs) remain one of the most promising materials of our times. One of the goals is to implement semiconducting and metallic SWCNTs in photonics and microelectronics, respectively. In this work, we demonstrated how such materials could be obtained from the parent material by using the aqueous two-phase extraction method (ATPE) at a large scale. We also developed a dedicated process on how to harvest the SWCNTs from the polymer matrices used to form the biphasic system. The technique is beneficial as it isolates SWCNTs with high purity while simultaneously maintaining their surface intact. To validate the utility of the metallic and semiconducting SWCNTs obtained this way, we transformed them into thin free-standing films and characterized their thermoelectric properties.

Organic solvent-assisted free-standing Li2MnO3·LiNi1/3Co1/3Mn1/3O2 on 3D graphene as a high energy density cathode

2015 ◽  
Vol 51 (91) ◽  
pp. 16381-16384 ◽  
Author(s):  
Yuelong Xin ◽  
Liya Qi ◽  
Yiwei Zhang ◽  
Zicheng Zuo ◽  
Henghui Zhou ◽  
...  
Keyword(s):  
Energy Density ◽  
Organic Solvent ◽  
Freeze Drying ◽  
Large Scale ◽  
High Energy ◽  
High Energy Density ◽  
Free Standing ◽  
3D Graphene ◽  
Active Particles

A novel organic solvent-assisted freeze-drying pathway, which can effectively protect and uniformly distribute active particles, is developed to fabricate a free-standing Li2MnO3·LiNi1/3Co1/3Mn1/3O2 (LR)/rGO electrode on a large scale.

Harvest rate of sooty shearwaters (Puffinus griseus) by Rakiura Māori: a potential tool to monitor population trends?

2004 ◽  
Vol 31 (3) ◽  
pp. 319 ◽  
Author(s):  
Jane Catherine Kitson
Keyword(s):  
New Zealand ◽  
Cross Section ◽  
Large Scale ◽  
Population Change ◽  
Population Trends ◽  
Harvest Rate ◽  
General Index ◽  
Careful Screening ◽  
Potential Tool

Sooty shearwaters (tītī, muttonbird, Puffinus griseus) are highly abundant migratory seabirds, which return to breeding colonies in New Zealand. The Rakiura Māori annual chick harvest on islands adjacent to Rakiura (Stewart Island), is one of the last large-scale customary uses of native wildlife in New Zealand. This study aimed to establish whether the rate at which muttonbirders can extract chicks from their breeding burrows indicates population trends of sooty shearwaters. Harvest rates increased slightly with increasing chick densities on Putauhinu Island. Birders' harvest rates vary in their sensitivities to changing chick density. Therefore a monitoring panel requires careful screening to ensure that harvest rates of the birders selected are sensitive to chick density, and represents a cross-section of different islands. Though harvest rates can provide only a general index of population change, it can provide an inexpensive and feasible way to measure population trends. Detecting trends is the first step to assessing the long-term sustainability of the harvest.

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