710 resultados para Moorabool Viaduct Sands


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A measurement investigation, at ADIF's test site at the O Eixo viaduct which is on the Spanish Santiago-Ourense high speed railway line, has been carried out during the last year. The main goal of the investigation is to study the effect of the cross-wind on railway overheads (catenaries) and the influence of the presence of windbreaks on the wind-induced motion of the railway overhead. A description of the O Eixo viaduct test site is presented in this paper, including the installed windbreaks, the sensor and power supply systems. Three catenary spans has been instrumented at the center point of the catenary span contact wire with one ultrasonic anemometer and two unidirectional accelerometers. Additionally, another ultrasonic anemometer placed in the central catenary span has been installed to provide reference wind data. Wind roses of wind speed and standard deviation of the accelerometers are presented. As expected, the four wind roses look very similar and the two dominant directions close to the perpendicular to the bridge longitudinal axes, north and south have been identified. The wind roses of the standard deviation of the acceleration shows that the acceleration of the catenary contact wire is related to the directions of the two dominant winds. The vertical standard deviation of the acceleration is higher than the horizontal one for the spans with windbreaks. It has also been observed that the presence of the windbreaks modifies the wind flow leading to a wind-induced motion of the catenary contact wire which shows a higher variability than the corresponding unprotected case. On the one hand, the baseline southerly wind configuration (south wind, windbreaks in the windward side and catenary in the leeward side) influence both the mean speed at the catenary and the turbulence intensity. On the other hand, the northerly wind configuration, windbreaks in the leeward side and catenary in the windward side, provide a reference to the response of the catenary for an unprotected railway overhead, and, as it is expected, the windbreak influence is much more reduced compared to the southerly wind configuration. Both the height of the windbreak and the eaves contribute to the increase in the turbulence intensity at the catenary contact wire height. It can be seen that the height of the windbreak plays a crucial role in the increase of turbulence intensity, much more intense than the presence of the windbreak eave.

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The dynamic behaviour of saturated sands has been studied from different perspectives. However, most experimental research on this field does not take into account the shear stress conditions existing prior to the application of dynamic loads; i.e., a null initial static shear stress (τo = 0) is assumed. The main objective of this work is to report on the influence that static shear stresses (τo) have on the behaviour of saturated sands under cyclic shear loads. This article presents the results and analysis of part of a wider experimental programme involving 30 monotonic and 26 cyclic simple shear tests for different combinations of static shear stress (τo) and cyclic shear stress (τc) (all undrained), besides identification and classification tests. The tested samples have been taken from the area of the North Entrance Mouth at the Port of Barcelona (Spain).

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The Vicario Viaduct is located in the A-44 motorway, in the South-East part of Spain. It crosses a natural gorge, near the town of Ízbor in the province of Granada. A single continuous steel concrete composite deck, 24 m wide and 175 m long, divided in two 87,5 m spans, has been built. The cross section is a single structural steel box, 8,00 m wide and 4,52 m deep. The total width of 24 m is reached adding a strut and tie system each 4,375 m on both sides of the box. The steel parts of the deck were entirely constructed in the workshop and then they were erected on site just behind one of the abutments. Finally a 27.5 m long steel nose was connected to launch the deck. The main problems have been the curved shape of the deck (1420 m radius in plan) producing a non symmetric transverse distribution of reactions on each support and the cantilever reaching 87,5 m long, producing a maximum deflection of 1500 mm

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Modal analysis of middle Miocene to Pleistocene volcaniclastic sands and sandstones recovered from Sites 1108, 1109, 1118, 1112, 1115, 1116, and 1114 within the Woodlark Basin during Leg 180 of the Ocean Drilling Program indicates a complex source history for sand-sized detritus deposited within the basin. Volcaniclastic detritus (i.e., feldspar, ferromagnesian minerals, and volcanic rock fragments) varies substantially throughout the Woodlark Basin. Miocene sandstones of the inferred Trobriand forearc succession contain mafic and subordinate silicic volcanic grains, probably derived from the contemporary Trobriand arc. During the late Miocene, the Trobriand outerarc/forearc (including Paleogene ophiolitic rocks) was subaerially exposed and eroded, yielding sandstones of dominantly mafic composition. Rift-related extension during the late Miocene-late Pliocene led to a transition from terrestrial to neritic and finally bathyal deposition. The sandstones deposited during this period are composed dominantly of silicic volcanic detritus, probably derived from the Amphlett Islands and surrounding areas where volcanic rocks of Pliocene-Pleistocene age occur. During this time terrigenous and metamorphic detritus derived from the Papua New Guinea mainland reached the single turbiditic Woodlark rift basin (or several subbasins) as fine-grained sediments. At Sites 1108, 1109, 1118, 1116, and 1114, serpentinite and metamorphic grains (schist and gneiss) appear as detritus in sandstones younger than ~3 Ma. This is thought to reflect a major pulse of rifting that resulted in the deepening of the Woodlark rift basin and the prevention of terrigenous and metamorphic detritus from reaching the northern rift margin (Site 1115). The Paleogene Papuan ophiolite belt and the Owen Stanley metamorphics were unroofed as the southern margin of the rift was exhumed (e.g., Moresby Seamount) and, in places, subaerially exposed (e.g., D'Entrecasteaux Islands and onshore Cape Vogel Basin), resulting in new and more proximal sources of metamorphic, igneous, and ophiolitic detritus. Continued emergence of the Moresby Seamount during the late Pliocene-early Pleistocene bounded by a major inclined fault scarp yielded talus deposits of similar composition to the above sandstones. Upper Pliocene-Pleistocene sandstones were deposited at bathyal depths by turbidity currents and as subordinate air-fall ash. Silicic glassy (high-K calc-alkaline) volcanic fragments, probably derived from volcanic centers located in Dawson and Moresby Straits, dominated these sandstones.

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Map on lining-paper.

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Mode of access: Internet.

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Paul Cézanne; 2 ft. 1 3/4 in.x 2 ft. 8 1/8 in.; oil on canvas

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"A contract between Amphibious Branch, Office of Naval Research, U. S. Naval Photographic Interpretation Center, Monitor [and] School of Civil Engineering, Cornell University. Beach accessibility and trafficability, project no. NR 257 001, contract N6onr, task order # 11. Petrographic analysis by Francisco J. Cordova. D. J. Belcher, director."