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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. 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>
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      <title>Transport Research International Documentation (TRID)</title>
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    <item>
      <title>AKASHI KAIKYO BRIDGE</title>
      <link>https://trid.trb.org/View/539927</link>
      <description><![CDATA[The Akashi Kaikyo Bridge (AKB) is a three-span, two-hinged stiffening girder system suspension bridge that spans the Akashi Strait.  It is the longest suspension bridge in the world by 581 m, surpassing the Humber Bridge in England, which has a center span of 1,410 m.  This article provides an in-depth examination of the design and construction of the AKB.  Designers constructed a 1:100 scale model and put it through repeated testing in order to develop a superstructure stable enough to withstand the 80 m/s winds of the strait.  Additionally, two types of earthquakes were calculated as factors in designing the bridge:  an earthquake of magnitude 8.5 on the Richter scale with an epicenter distance of 150 km and an earthquake occurring with recurrent cycle of 150 years within 300 km of radius of the bridge site.  The foundations of the two main towers transfer the approximately 120,000 tons (108,864,000 kg) of downward load from the huge main towers to the supporting ground.  While constructing the 282.2-m high main towers, it was important to maintain vertical precision.  The first stage of cable installation was the pilot rope spanning, which was done by helicopter.  In the final stage before completion, 90,000 tons (81,648,000 kg) of steel was used in constructing the stiffening girders, which are 35 m wide and 14 m high.  The girders were assembled into large blocks which were then installed as single units using floating crane ships. To reduce stiffening girder torsional vibration caused by wind, stabilizing plates were installed under the median strip of the deck.]]></description>
      <pubDate>Wed, 28 Oct 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/539927</guid>
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      <title>CABLE-STAY CONUNDRUM</title>
      <link>https://trid.trb.org/View/487819</link>
      <description><![CDATA[Since the opening of the Fred Hartman Bridge in Baytown, Texas, in late 1995, high-amplitude rain-induced vibrations have caused weld failures and fatigue cracks in the deck-level guide pipes of more than 100 stays.  The Veterans' Memorial Bridge in Port Arthur, Texas, which opened in 1991, has significant differences in its superstructure flexibility from the Fred Hartman Bridge, but it too has experienced rain vibrations.  Researchers are just beginning to study vibrations on cable-stayed bridges caused by wind and rain. One factor in rain vibrations of cable stays seems to be the materials involved, typically high-strength prestressing steel covered by polyethylene pipe.  The pipe is filled with cemetitious grout for corrosion protection.  An extremely smooth polyvinyl fluoride tape wrap protects the polyethylene pipe from ultraviolet degradation.  The smooth tape facilitates movement of water droplets around the stay and promotes the surface tension to form the rivulets.  By comparison, some older cable-stayed structures in which the stay pipe is steel rather than polyethylene may have formed a surface roughness that impedes the movement of water and disrupts the flow boundary.  It has been customary to install a small neoprene or rubber damper at the end of the steel pipe as the stay cable passes into the anchorage at the deck.  This small, compact damper is designed for the low-amplitude, high-frequency vibrations associated with buffeting and vortex shedding caused by wind alone.  It was not, however, designed for the high-amplitude, low-frequency oscillations associated with rain-induced vibrations.  Another common link among observed rain vibrations is the natural frequency of the stay cables. Generally, it is stay cables with natural, second- and third-mode frequencies less than 2 Hz that have experienced this phenomenon.  Two passive vibration mitigation methods are currently available:  cable restrainers tied between the stays and mechanical dampers placed near the ends of the stays at the deck or tower.  Other systems are also being evaluated. Restrainer cables have been used as an interim solution on a number of cable-stayed bridges worldwide.  Japanese and European engineers have added a helical strake or protuberances to the stay pipe of several cable-stayed bridges.  This disrupts the flow of water, preventing a continuous rivulet from forming. Aerodynamic dampers in the form of plates are another possible solution.  A sidebar discusses cable restrainer assemblies being tried on the Fred Hartman Bridge.]]></description>
      <pubDate>Fri, 14 Aug 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/487819</guid>
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      <title>MOTOR VEHICLE SUSPENSION SYSTEMS: VIBRATIONAL EFFECTS AND STABILITY. (LATEST CITATIONS FROM INFORMATION SERVICES IN MECHANICAL ENGINEERING DATABASE)</title>
      <link>https://trid.trb.org/View/388698</link>
      <description><![CDATA[The bibliography contains citations concerning the relationship between motor vehicle suspension systems and vehicle vibration and ride stability.  Included are studies correlating uneven tire wear and steering difficulties with suboptimal suspension systems.  Hydropneumatic leveling, independent suspension, and active suspension systems are discussed.  The use of composite materials, such as fiberglass, in suspension springs is also presented.  (Contains a minimum of 245 citations and includes a subject term index and title list.)]]></description>
      <pubDate>Fri, 08 Apr 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/388698</guid>
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      <title>GUIDELINES FOR PREVENTION OF EXCESSIVE SHIP VIBRATION</title>
      <link>https://trid.trb.org/View/157367</link>
      <description><![CDATA[The aim of this paper is to guide the naval architect through a vibration check procedure for his design in order to avoid harmful vibration when the ship enters service.  Efforts have been made to give a description of when to do what at the various stages of a ship design and how to do it by the use of simple equations and empirical formulas.  Just a necessary minimum of investigations is suggested and the results are evaluated at each step of procedure.  The guide is supplied with a short introduction to the various items to be investigated to make the designer qualified to take the first decisions in the evaluation process without assistance from vibration experts. Additional costly and time-consuming calculations are recommended only when the preliminary investigations have revealed that serious vibration problems may occur or that the margins are small.  According to experience, such problems are mainly related to the pressure impulses from the cavitating propeller(s) and the dynamic response of the afterbody.  Finally, the use of the procedure is illustrated with examples, including one case where both improved propeller design and response calculations with the finite-element method had to be carried out at the final design stage.]]></description>
      <pubDate>Wed, 18 Feb 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/157367</guid>
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    <item>
      <title>VIBRATION TEST OF ROLL-ON ROLL-OFF SHIP</title>
      <link>https://trid.trb.org/View/154503</link>
      <description><![CDATA[The largest roll-on roll-off ship in the world was built in MHI's Nagasaki Shipyard recently.  The ship has huge complicated substructures such as ramp-post, ramp-way and superstructure in the after body and has no transverse bulkhead in the hold part and because of this structure it is difficult to estimate its vibration characteristics.  In constructing this ship vibration calculations were performed applying the newly developed Modal Synthesis Technique and the hull-bottom coupled vibration analysis method in order to design a vibration-proof structure.  On completion, exciter tests and measurements at sea were conducted.  The test results are as follows: (1) Hull vibration is strongly coupled with the bottom vibration so that the frequency of higher nodal vibration becomes lower than that of bulk carriers. (2) Modal synthesis technique is useful for the analysis of higher mode vibration of the after body of roll-on roll-off ships.]]></description>
      <pubDate>Wed, 27 Aug 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/154503</guid>
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    <item>
      <title>VIBRATIONS IN THE SHIP'S HULL</title>
      <link>https://trid.trb.org/View/153355</link>
      <description><![CDATA[This article deals with the response of ship superstructures to vibrations in the hull.  In a 6-year study Det norske Veritas measured vibrations in the aftership of more than 100 vessels and from this it was seen that 50 had unacceptable levels of vibration in the superstructure.  Of these vessels 80% showed the propeller as the single major source of excitation.  In 31 of the 50 ships the problem was one of localised vibration of the deck of bulkhead and in most cases was solved by local stiffening, but for 17 of those remaining, the problem was one of global vibration of the hull and superstructure which would be costly to eliminate but which could have been avoided through greater effort and calculation at the design stage.  Examples of analysis are given for four different types of merchant ship and the article concludes that experience has shown it possible to completely eliminate or reduce the degree of vibration in hull and superstructure if one reduces excitation forces to a minimum, takes into account the problem of vibration during the construction of the superstructure and supports, and guards against excitation to the superstructure's natural frequency and to hull-induced resonance frequencies.  Order from BSRA as No. 52,364.]]></description>
      <pubDate>Wed, 07 May 1980 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/153355</guid>
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    <item>
      <title>AFT END SHAPING TO LIMIT VIBRATION</title>
      <link>https://trid.trb.org/View/92230</link>
      <description><![CDATA[The design and operational experience over the last decade with nine selected ships are reviewed.  Technical particulars of the ships and general comments on levels of propeller excited vibration are given, and details of waterlines and sections, together with contours of "Taylor" wake through the propeller disc derived from model experiments are presented.  An empirical method of selecting propeller, diameter, rate of revolutions and main propulsion machinery for a given wake for minimum levels of cavitation vibration is described.  The assessment of vibration levels is discussed.]]></description>
      <pubDate>Sat, 15 Sep 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/92230</guid>
    </item>
    <item>
      <title>NOISE ABATEMENT ON SHIPS</title>
      <link>https://trid.trb.org/View/93752</link>
      <description><![CDATA[The main aim of the project was: 1) to establish a basis for the prediction of sound levels at the design stage, 2) to make clear the effect of design measures for the reduction of initiation and distribution of vibrations creating sound, and 3) to work out proposals for sound reducing design measures.  Excitation sources, sound transmission and calculation, rules and recommendations, problem areas, established designs and economic data, and procedures for newbuildings and existing vessels are dealt with.  Order from NSFI as No. 17237.]]></description>
      <pubDate>Sat, 15 Sep 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/93752</guid>
    </item>
    <item>
      <title>REDUCING NOISE RADIATED BY DIESEL ENGINES -- 1, 2</title>
      <link>https://trid.trb.org/View/92155</link>
      <description><![CDATA[Part 1 of this 2-part article discusses 4 basic approaches to controlling noise radiated by engine surfaces: (1) Control noise generation from sources within the engine and its accessories; (2) Reduce transmission of vibration from sources to radiating surfaces; (3) Control vibration of external surfaces of the engine; (4) Enclose the engine. Ways of implementing each approach are outlined.  The relative importance of combustion noise and mechanical noise is discussed, and a method of diagnosing the contribution to the overall engine noise from each surface area is covered. Part 2 describes in some detail the methods of diagnosing the vibrations from crankcase, cylinder block, valve gear covers and sump, and suggests ways of damping them to achieve an overall reduction of 5dBA or more.]]></description>
      <pubDate>Tue, 28 Aug 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/92155</guid>
    </item>
    <item>
      <title>VIBRATION CONTROL APPARATUS USING ACTIVE FORCE GENERATOR, FOR SHIPS</title>
      <link>https://trid.trb.org/View/91474</link>
      <description><![CDATA[As an alternative to other means of reducing the vibration of an accommodation structure, the Authors have developed a vibration-control apparatus which reduces hull vibration by producing an "artificial" vibration which counteracts the structural vibration.  The apparatus, which has been found satisfactory in various tests in actual ships and whose construction and operation are described in the article, has the following features: (i) It senses vibration of the accommodation structure with an acceleration sensor and selects some fundamental waves.  The apparatus operates automatically at the same frequency as, and opposite phase to the strongest fundamental wave.  (ii) It can reduce any kind of hull vibration, irrespective of its source (propeller, main engine, etc.).  (iii) It can be placed at any position in the ship.  (iv) It produces artificial vibration by mechanism consisting of two electrically-driven shafts which have counterweighted wheels attached to them and which rotate in opposite directions; sine wave vibration is produced.  (v) The amplitude of the exciting force can be altered by changing the counterweights.  (vi) Where there are two or more strong fundamental waves in the accommodation structure vibrations, additional apparatus can be used to work against each of the waves individually. Order from BSRA as No. 50,719.]]></description>
      <pubDate>Tue, 31 Jul 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/91474</guid>
    </item>
    <item>
      <title>VIBRATION OF SHIP SUPERSTRUCTURES--CAUSES AND REMEDIES</title>
      <link>https://trid.trb.org/View/86646</link>
      <description><![CDATA[Continuing their description of examples of investigations on problems in superstructure vibration, the authors consider the case of an 87,000-dwt bulk carrier in which the longitudinal vibration was particularly bad when the ship was in ballast.  This ship, propelled by a low-speed (122 rpm) Diesel engine, needed a six-bladed propeller to replace its five bladed one; this case is in contrast with that of a 160-m long containership investigated.  In the latter ship, propelled by medium-speed Diesels driving a four-bladed propeller at 135 rpm, there was no risk of propeller-excited longitudinal vibration of the superstructure, whether the propeller had four, five, or six blades.  Whatever steps are taken to cure such vibration problems, or to prevent them at the design stage, the superstructure block remains an "elastic system" with a natural frequency of longitudinal vibration liable to be excited by a major excitation source in the propulsion installation.  Methods that can be used by the designer in approaching this problem are described, with examples, under the headings:--Approximate Methods Evaluating the Natural Frequencies of Superstructure Vibrations; Evaluation of Natural Frequencies of Superstructure Vibrations; Evaluation of Natural Frequencies taking Experimental Results into Account; Superstructure Vibration Calculations by the Finite Element Method.  In the concluding section of the article, the authors mention the difficulties inherent in the prevention of excessive superstructure vibration and in mitigating it in existing ships.  A Bureau Veritas Information Note on limiting shipboard vibrations should be of practical value to the designer interested in superstructure vibration; some information from the Note is included in the article.  More knowledge is needed on damping, hydrodynamic excitations, and added mass, and the Society is continuing studies on these matters.  Order from BSRA as No. 50,005.]]></description>
      <pubDate>Sat, 26 May 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/86646</guid>
    </item>
    <item>
      <title>NOISE PREDICTION AND PREVENTION IN SHIPS</title>
      <link>https://trid.trb.org/View/76284</link>
      <description><![CDATA[The prediction and prevention of structure-borne sound on board merchant ships are discussed.  Results of full-scale and model-scale experiments have indicated that the main power flow in the vertical direction in a ship structure is determined by the propagation of flexural waves in the plate elements.  Based on these results a prediction model is developed.  It is found that the velocity level of a deck is a function of the input power at the source, wave-numbers, masses, losses and dimensions of the plate elements in the structure.  The attenuation of structure-borne sound is also a function of frequency.  Predicted and measured structure-borne sound levels are compared.  The effects of damping layers and resiliently mounted superstructures and accommodation systems are also discussed.]]></description>
      <pubDate>Tue, 31 Oct 1978 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/76284</guid>
    </item>
    <item>
      <title>A HYDRODYNAMIC STUDY OF THE COCHLEA--CHANNELLED STERN</title>
      <link>https://trid.trb.org/View/71824</link>
      <description><![CDATA[The typical properties of a new stern shape provided with cochlea (helical) channels are displayed by comparing many model-test results.  The test and design methods of the new stern shape are thoroughly explained.  The manipulation of the wake by means of the channel system leads to the following results: 1. A reduction of the thrust pulsation of the single propeller blades.  2. A drastic reduction in amplitude of the main frequency of the blade thrust, leading to its complete elimination.  3. A shift to deeper sectors of the propeller disc of the reduced blade thrust maxima. 4. A counter-propeller effect generated by the vortex induced in the wake.  5. A limitation of the increase of towing resistance due to the wake vortex and a possible reduction below the resistance of the corresponding traditional ship.  6.  A conveyance into the propeller disc of the (viscous) wake having lapped the surface of hulls provided with more than one propeller.  The combined effect of these contributions to saving of propulsive power leads to a very substantial benefit.  A power saving of the order of 25% was achieved on comparative self-propulsion tests performed with two twin-screw models as well as drastic reduction of propeller-induced hull vibrations.  Similar benefits could be expected from the adoption of the cochlea channelled stern on any kind of ship, not only with twin-screw hulls.  Order from: BSRA as No. 47,492.]]></description>
      <pubDate>Wed, 29 Mar 1978 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/71824</guid>
    </item>
    <item>
      <title>PREVENTION AND REMEDY OF SHIP VIBRATION</title>
      <link>https://trid.trb.org/View/60845</link>
      <description><![CDATA[To prevent or remedy ship vibration it is important to avoid resonance and to reduce exciting forces.  To do this, it is necessary to estimate the natural frequencies of various hull structures and the magnitude of exciting forces, particularly in the design stage.  The prevention of vibration is more important than its cure, since the latter can be very expensive.  The Authors present a practical design method for the prevention of ship vibrations, based on calculating the natural frequencies of the hull girder, superstructure, tanks, and other important structural units, and also on calculating the magnitude of exciting forces due to the propeller and the propulsion plant.  Order from BSRA as No.  46,861.]]></description>
      <pubDate>Thu, 16 Feb 1978 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/60845</guid>
    </item>
    <item>
      <title>PREVENTION OF ENGINE-ROOM VIBRATION. 1ST REPORT: AN ENGINE-ROOM DOUBLE BOTTOM</title>
      <link>https://trid.trb.org/View/53772</link>
      <description><![CDATA[An account is given of a vibration analysis, using the finite-element method and plate theory, of an engine-room double bottom with the aim of establishing a simplified formula for design use.  The formula thus evolved takes into consideration the effects of longitudinal irregularity of double-bottom rigidity, the effects of shear flexibility on bending vibration, the stiffness of ship side members, and the rigidity of the Diesel engine and its bed.  The formula, which has been modified on the basis of measured results in actual ships, enables not only the fundamental but also the secondary natural frequencies of an engine-room double bottom to be examined with a calculation accuracy within about 10%.]]></description>
      <pubDate>Wed, 31 Aug 1977 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/53772</guid>
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