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原文传递 Structural Safety Evaluation of Suspension Bridge Parallel-Wide Cables.

题名：	Structural Safety Evaluation of Suspension Bridge Parallel-Wide Cables.
作者：	CAMO, S.; MAYRBAURL, R. M.
关键词：	Suspension-bridges; Structural-analysis; Safety-evaluation; Cables-Ropes.;Bridges-Structures; Corrosion-; Inspection-; Degradation-; Strength-; Highway-bridges.
摘要：	It is not possible to determine the internal condition of a suspension bridge cable without removing the outer wrapping or covering. Historically, engineers have used various means of looking inside the cable, from simple removal of a few wires of the wrapping, which exposes the outer wires only, to unwrapping the cable along its full length and driving wedges to the center. Gradually, engineers are coming to a consensus on the need to wedge to the center of the cable at more than a limited number of locations. Of course, the aging stock of bridges is driving this accord on method and the data that are required. A definitive specification for performing cable integrity evaluations does not exist at this time. Although there is a drive for consensus, each investigator has a bias toward a particular method of inspection and/or analysis technique. This investigation was undertaken to synthesize the viewpoints and to create a set of standards that encompasses all this experience. The results of the research are divided into a practical Guidelines manual for inspectors and a Report that details the background and findings that support the recommendations. As part of this work, a database has been prepared for the Report that summarizes the basic design features of all suspension bridges in the U.S. and Canada with main spans exceeding 700 feet. It is mostly concerned with information about the cables. Only a limited amount of data about the internal condition of these cables have been received and included in the database. The experience of the engineering firms that are active in inspecting primarily east coast U.S. bridge cables is that deterioration is not limited to the low points, which were assumed previously to be in the worst condition, but is often more prevalent at locations further up on the cable. This has led to development of recommendations about the timing of inspections, that is, when they should begin and where on the cable they should take place. The Report recommends that the first internal inspection take place thirty years after the cables have been put into use, and that three locations per cable be inspected at that time. The frequency and number of locations of subsequent inspections depend on the conditions revealed by previous inspections.
报告类型：	科技报告