The abutments provide a secure anchorage for the bridge cables at the ends of the span. They are reinforced concrete blocks, cast directly against a benched and keyed rock surface. Each abutment is secured to the underlying rock with 24 or 28 post-tensioned rock anchors. Each rock anchor consists ofmm diameter strands of 30 to 60 m length, installed at a 1:1 batter. The abutments and rock anchors were designed to maintain a state of nominalpression in the rock under all service conditions. Changes in bridge cable forces under expected service loads were found to introduce large shears where the abutment bears on the rock. Therefore shear keys were provided in the rock, allowing the rock anchors to remain under a fairly constant stress. Ducts for the bridge cables were formed by casting 324 mm diameter straight steel pipes into the anchorages. Free access to the back wall of the abutment allows installation and adjustment of the cables. See full list on The four main cables carry all loads to the abutments. They areprised of the Freyssinet prestressing strand and anchor system developed for use in cable-stayed bridges. Each cable consists ofmm diameter strands each 7-wire galvanized strand is enclosed within a wax filled HDPE sheath. This system provides adequate corrosion protection without amon cable duct, thus permitting the installation, removal, or replacement of individual strands. The strands are bundled into a hexagonal shape by cable bands that also serve to secure the floor beams to the cable. Friction between the cable bands and the strand, through the sheaths, was considered inevitable but unreliable. Therefore, the bridge was designed to perform adequately both with and without the effects of this friction. The drape of the cables under structural dead load at a nominal temperature of 15°C is 7.85 m. Under the influence of live loads, temperature changes, and other transient effects, the drape is expecte... See full list on The steel deck framing serves to tie the cables together and distribute the loads from the foot path and the pipe to the cables. Material delivery and equipment access issues at the site dictated light erection equipment and therefore relativude IPE330 transverse floor beams spaced at 2.5 m along the cable, and simply supported UPN200 stringers to frame the foot path. The floor beams are clamped to the cables using bent steel plate cable clamps that are bolted to the bottom flanges of the floor beams. The deck stringers are bolted to the top flanges of the floor beams, with additional diagonal braces to the bottom flanges, to restrain lateral-torsional buckling of the floor beams. Additional lateral-torsional buckling restraint is provided by bridging diaphragms near the ends of the floor beams. These diaphragms are provided in every 20th floor beam bay, and are connected to intermediate floor beams with continuous longitudinal br... See full list on mctNA1Q8x65w Figure 12.1 The excavation of an exposed cave at Jebel Irhoud, Morocco, where hominin fossils were found in the 1960s and in 2007. Dating showed that they represent the earliest-known modern Homo sapiens.. The walls of a pink limestone cave exposed to the outside world in the hillside of Jebel Irhoud jutted out of the otherwise barren landscape of the Moroccan desert (Figure 12.1). YcjdzNZ3Tdzd Sep 06, 2021 · As Britain’s longest established monthly aviation journal, Aviation News is renowned for providing the best coverage of every branch of aviation. Each issue features the latest news and in-depth features, plus firsthand accounts from pilots putting you in the cockpit. Covering both modern military and civil aircraft, as well as classic types from yesteryear, it … uKTDc7dfdTey Andes Small Construction Bridge Crane , Find Complete Details about Andes Small Construction Bridge Crane,Construction Bridge Crane,Crane,Building Crane ... CazrAHUFYm5t
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