<?xml version="1.0" encoding="utf-8"?><rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>TRB Publications Index</title><link>http://pubsindex.trb.org/</link><atom:link href="http://pubsindex.trb.org/common/TRIS Suite/feeds/rss.aspx?tc=NN%3AQtpbcg%2A" rel="self" type="application/rss+xml" /><description></description><language>en-us</language><copyright>Copyright © 2015. National Academy of Sciences. All rights reserved.</copyright><docs>http://blogs.law.harvard.edu/tech/rss</docs><managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor><webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster><image><title>TRB Publications Index</title><url>http://pubsindex.trb.org/Images/PageHeader-wTitle.png</url><link>http://pubsindex.trb.org/</link></image><item><title>Systematic Assessment of Nondestructive Evaluation Techniques for External Post-tensioning and Stay Cable Systems</title><link>http://pubsindex.trb.org/view/1495600</link><description><![CDATA[Nondestructive evaluation (NDE) can provide invaluable information about the condition of tendons in post-tensioned and cable-stayed bridges, which can facilitate preventative actions to mitigate further deterioration. To date, the use of nondestructive testing methods for routine maintenance of bridges has been relatively low, partly due to limitations of available technologies but mainly owing to a lack of know-how regarding existing NDE techniques and guidelines. This study aims to develop guidelines to assist bridge owners and engineers in selecting the most appropriate NDE method or combination of methods for assessing the condition of in-service post-tensioning and stay cable systems. An extensive experimental study is conducted on a full-scale post-tensioned girder specimen and large-scale stay cable specimens to evaluate the performance of various NDE methods in terms of detecting location and severity of numerous strand and grout defects. Decision metrics were developed considering multiple criteria such as precision, accuracy, ease of use, inspection requirements, and cost to facilitate selecting the most appropriate NDE method for assessing a particular defect condition. Overall scores for the tested NDE methods in identifying various defect conditions in different parts of the PT and stay cable systems were calculated using a weighted sum model. These scores were used to develop a list of ranked NDE methods for evaluating a particular defect condition within a specific location, and for a specific duct material.]]></description><pubDate>Fri, 26 Jan 2018 09:47:13 GMT</pubDate><guid>http://pubsindex.trb.org/view/1495600</guid></item><item><title>Inspection and Maintenance of Bridge Stay Cable Systems</title><link>http://pubsindex.trb.org/view/772974</link><description><![CDATA[This synthesis identifies and explains various inspection and maintenance techniques for bridge stay cable systems.  It discusses both short- and long-term approaches.  Topics covered included methods for inspections and assessments, including nondestructive testing and evaluation procedures; repair and retrofit; methods for control of cable vibrations, including rain-wind vibrations; stay cable fatigue and failure; effectiveness of various inspection and repair methods; limitations of available technologies; and trends and recommendations for future study.  This synthesis effort was based on a comprehensive review of domestic and international literature on the inspection, repair, testing, and design of stay cable.  On-line sources of information as well as engineering databases were examined.  A questionnaire was distributed to all state and provincial departments of transportation in the United States and Canada to determine current state of the practice.  Also, contacts were made with a number of knowledgeable individuals for information.  Additional information was gathered from the examination of test reports and condition assessments from inspection of cable-stayed bridges, a review of a limited number of maintenance and inspection manuals for cable-stayed bridges, and a patent search using the U.S. Patent and Trademark Office database.]]></description><pubDate>Thu, 26 Jan 2006 10:40:05 GMT</pubDate><guid>http://pubsindex.trb.org/view/772974</guid></item><item><title>FATIGUE ASSESSMENT OF CABLE SYSTEMS OF LONG-SPAN CABLE-STAYED BRIDGES</title><link>http://pubsindex.trb.org/view/450978</link><description><![CDATA[Cable systems of a cable-stayed bridge consist of cable and cable anchorage.  Cable tension caused by prestress, dead load, and live load acts directly on the cable anchorage.  In addition to direct tension, bending deformation caused by live load, temperature changes, and wind load act on the anchored stay cables.  Furthermore, wind-induced oscillations may be considered.  Because the cable tension and bending deformation occur repeatedly, it is necessary to verify fatigue behavior. The structural details of cable anchorages are complex, making it difficult to evaluate their fatigue resistance.  Therefore, fatigue tests were conducted on full-scale specimens that include proposed anchorages and cables to examine their performance.  The obtained results show that fatigue cracks initiated at the welded toe of the bearing plate to anchor web plates were caused by plate bending; therefore, some refinements of structural details are necessary.  The bending fatigue strength of semi-parallel wire cables socketed by two types of anchorage were both proved to be sufficient for use as stay cables for an 870-m span cable-stayed bridge.]]></description><pubDate>Wed, 06 Sep 1995 00:00:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/450978</guid></item><item><title>MEASUREMENT OF STRESS IN CONCRETE PAVEMENTS</title><link>http://pubsindex.trb.org/view/146452</link><description><![CDATA[Sudden compressive failures of concrete pavements (blowups) are a serious problem for highway maintenance departments. In an effort to predict when blowups will occur, a method of measuring residual stresses within a concrete pavement has been developed.  In the procedure, electrical strain gauges are attached to the wall of a corehole by means of a specially designed installation tool.  The corehole is overcored and the relief strains are measured.  Available theory has been adapted to allow computation of longitudinal stress at the level of the gauges.  Laboratory tests have validated the procedure, but results from tests on actual pavements have proved to be somewhat erratic. /Author/]]></description><pubDate>Wed, 27 Feb 1980 00:00:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/146452</guid></item><item><title>DRILLING AND BLASTING</title><link>http://pubsindex.trb.org/view/52820</link><description><![CDATA[This paper reviews the state of the art and future research in conventional drilling and blasting.  Although machine tunneling is relatively new, the drilling and blasting techniques now being used have been practiced for several centuries and it is doubtful whether they will become completely obsolete.  Rock that is too hard to cut economically with a machine must be excavated in the conventional manner.  Tunneling machines are expensive both to purchase and to install; consequently they are frequently uneconomical in shorter tunnels.  As a result of the many improvements in excavating tunnels by drilling and blasting, tunnels are today being driven twice as fast and sometimes with less labor than they were forty years ago. Improvements include the drill jumbo, removable drill bits, better steels, more powerful pneumatic drills, and larger and faster mucking machines.  Research in improved drilling and blasting operations include the following areas: Faster drilling, in order to substantially increase the current drilling speed.  Automation of drilling mechanisms, to eliminate the delay now caused by human factors.  Mechanical loading of explosives, to substantially save in labor cost and loading time.  Hydraulic drills and new rock-breaking techniques will possibly eliminate the need for explosives. Smoother excavation will reduce the increased cost for labor and ground supports and to the cost of concrete linings. Faster muck removal could be achieved through education and improved labor-management relations.  Finally, measuring surfacing vibrations must be accurately predicted particularly when blasting occurs under densely populated areas.]]></description><pubDate>Thu, 13 Oct 1977 00:00:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/52820</guid></item><item><title>SOILS EXPLORATION AND DESIGN CONCIDERATIONS FOR THE GREATER NEW ORLEANS EXPRESSWAY. I. EXPLORATION AND TESTING</title><link>http://pubsindex.trb.org/view/121612</link><description><![CDATA[EXPLORATION AND TESTING WERE CONDUCTED TO OBTAIN DATA FOR THE CONSTRUCTION OF THE WORLD'S LONGEST HIGHWAY BRIDGE, A 24 MILE LONG PRESTRESSED CONCRETE BRIDGE, ACROSS LAKE PONTCHARTRAIN. THE DEPTH OF THE LAKE IS RELATIVELY UNIFORM, GENERALLY VARYING FROM 13 TO 17 FEET BUT BECOMING SHALLOWER CLOSER TO SHORE. GEOLOGY AND SITE CONDITIONS WERE DESCRIBED. THE PRESENCE OF KNOWN DEPOSITS OF SOFT AND VERY COMPRESSIBLE MATERIALS INDICATED THE NECESSITY FOR EXTENSIVE SUBSURFACE EXPLORATION. EXPLORATORY BORINGS WERE MADE WITH ROTARY DRILLING EQUIPMENT. BORINGS AT THE SITES OF THE TWO BASCULE SPANS WERE CARRIED TO 200 FEET BELOW THE WATER SURFACE. OTHERS WERE TO 100 FEET AND 140 TO 160 FEET; 60 FEET AT BRIDGEHEAD PLAZA. SAMPLES WERE NOT REQUIRED AT DEPTHS OF LESS THAN 40 FEET UNLESS THE MATERIAL ENCOUNTERED WAS NOTICEABLY DIFFERENT FROM THE USUAL SOFT BOTTOM MUCK. BELOW DEPTHS OF 40 FEET, SAMPLES WERE REQUIRED AT EVERY CHANGE IN SOIL TYPE AND AT INTERVALS OF NOT MORE THAN 10 FEET. THE EXPLORATIONS INDICATED THAT THE DESIGN AND CONSTRUCTION OF THE PLAZA FILL WOULD BE COMPLICATED BY THE VERY SOFT MATERIAL PRESENT. THE LABORATORY PROGRAM CONSISTED PRIMARILY OF CLASSIFICATION TESTING, SHEAR STRENGTH DETERMINATIONS, AND CONSOLIDATION TESTING. THE HIGHLY ORGANIC SURFACE SOILS FROM THE SOUTH APPROACH ROAD AREA WERE TESTED TO DETERMINE THE PH AND ORGANIC CONTENT. A SOILS LOG WAS PREPARED TO SHOW THE SOIL STRATIFICATION, SAMPLE LOCATION AND CLASSIFICATION, AND ALL TEST RESULTS.]]></description><pubDate>Sun, 15 Aug 1971 00:00:00 GMT</pubDate><guid>http://pubsindex.trb.org/view/121612</guid></item></channel></rss>