Draw Bridge & Wire Rope Testing

WIRE ROPE on drawbridges is in constant motion and under load. These ropes are exposed to the elements, sometimes, hostile. Prudent and frequent examination, lubrication and tensioning are a must. These ropes are sometimes covered with aged asphalt based lubricant making it impossible to conduct visual examinations. The ropes are close together and need to be "spread apart" in order to conduct inspections of any type. Many of these ropes are approaching the end of their useful lift due strictly to age, and should be inspected.

ELECTROMAGNETIC INSTRUMENTATION is used during the lift rope inspection. This instrumentation measures the loss of metallic area and localized faults during the test. The loss of metallic area or LMA can be caused by internal or external corrosion, wear, damage, etc.. Local faults, or LF can be due to internal or external faults such as broken wires, pockets of corrosion, etc. The EM instrumentation is pulled to the upper limit and then lowered to the bottom limit. Special spreaders are used to spread the rope so the sensor head will fit between the ropes. Test results are recorded on a strip chart recorder. The strip chart is interpreted by the inspector and any defects or loss of metallic area is noted. A field test report, explaining the general condition of the wire rope is left with the client prior to the inspector leaving the job site. Formal computerized reports will be sent to the client within approximately two weeks after the inspection is complete.

PROPER LUBRICATION will help to extend the life of the lift rope. The internal portion of the wire rope is subject to corrosion. A good penetrating lubricant will protect the inside and outside of the rope and allow the rope to "breathe" so that water, in the form of condensation can find its way out of the rope structure. Heavy grease coatings on the outside of the rope typically do not penetrate into the rope. Moisture and foreign materials are sealed inside; condensation can't get out of the rope structure. The result is an established and advanced state of deterioration caused by corrosion. Halkin uses a light- weight, penetrating, biodegradable, synthetic lubricant. This lubricant penetrates to the inner most wires and preserves and lubricates them still allowing the rope to "breathe". In many cases, the wire ropes must be cleaned prior to lubrication. Cleaning is accomplished with the use of a contained, high pressure, hot water spray unit. The waste material is collected and discarded of properly.

PROPER TENSIONING of lift ropes is necessary in order to ensure adequate support of the bridge and counterweight. Halkin uses hydraulic equipment to tension the ropes to correct and equal values. The ropes are tensioned in accordance with the manufacture's recommendations. When tensioning the wire ropes, the current condition and strength is taken into consideration and the client is made aware of the new safety factor. He can then contact the bridge designer in order to obtain new structural data. Before and after data is included with the formal report. Halkin can also help you with the installation of new ropes as replacements or new projects.

ALL WIRE ROPE were out eventually, gradually losing work capability throughout its useful life, making periodic inspections, lubrication and tensioning necessary. Defects detected during an NDT inspection can help pinpoint the factors leading to and eventual guy rope failure. Many ropes have to be retired due to damage caused by other, outside sources. NDT inspections can help our client to diagnose these conditions before its to late. The life of your investment can be extended once these outside sources are identified and corrected. All Halkin Inspectors are certified in accordance with ASNT and ASTM guide lines. The instrumentation used during the testing procedures meets appropriate ASTM standards. Our Quality Assurance Manual is available for your review on written request.

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