Inspection and Maintenance of Bridge Stay Cable Systems (2005)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

68 NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM SYNTHESIS TOPIC 35-07 INSPECTION AND MAINTENANCE OF BRIDGE STAY CABLE SYSTEMS QUESTIONNAIRE With this request for information, we are seeking your help in developing a synthesis report on inspection and maintenance of stay cables in cable-stayed bridges. You and your agency have been selected because of the relevant knowledge and expe- rience that we believe can be shared with us that are important to the success of this effort. We are striving to make the out- come of this effort (i.e., the synthesis report) a valuable and state-of-the-art resource for those such as yourself who are involved in the inspection, design, maintenance, or repair/retrofit of stay cables. The synthesis will focus on the advantages and limitations of various non-destructive test methods, repair procedures, preventive maintenance strategies, vibration con- trol methods, corrosion protection systems, fatigue, etc. Please feel free to contact the consultant for this synthesis project, Dr. Habib Tabatabai, at (414) 229-5166 or ht@uwm.edu should you have any questions. You may also receive a call or e-mail from the consultant for the purpose of clarifying or augmenting your answers to the questions. Please provide any additional information that you feel is relevant to the answers provided in the questionnaire. Thank you in advance for your valued input into this effort. Respondent Information: Please provide the information requested below for the person completing this questionnaire (if you received the question- naire and someone else is in a better position to respond, please forward the document to that person). Agency: Name: Title: Street address: City: State: Zip code: Telephone: Fax: E-mail: Please return the completed questionnaire and any supporting documents by e-mail, fax, or mail by Friday March 26, 2004 to: Habib Tabatabai Department of Civil Engineering & Mechanics University of Wisconsin–Milwaukee 3200 N. Cramer Street Milwaukee, WI 53211 Telephone: (414) 229-5166 Fax: (414) 229-6958 E-mail: ht@uwm.edu APPENDIX A Survey Questionnaire

69 QUESTIONS Please feel free to expand on your answers to the following questions. If you need additional space, you can use the comments section at the end of this questionnaire. 1) Are you or your agency involved in the design, fabrication, inspection, testing, repair, maintenance, or retrofit of stay cables in cable-stayed bridges? Yes  No  If the answer is “Yes,” please proceed to the next question. If the answer is “No,” please return the questionnaire as directed above and thank you for your time. Please note that submitting a “blank” questionnaire is preferred to not submitting. 2) Is your agency an owner (or responsible for the maintenance) of at least one cable-stayed bridge? Yes  No  Soon  If the answer is “Yes” or “Soon,” please proceed to the next question. If the answer is “No,” please proceed to ques- tion No. 5. 3) How many cable-stayed bridges are under the jurisdiction of your agency or are maintained by your agency? 1  2  3  over 3  (please provide number) 4) Please provide the following information on each of the cable-stayed bridges that are maintained by your agency. (If you have more than two cable-stayed bridges, please provide the requested information on additional sheets. Also, please note that MTE refers to the main tension-resisting elements in the cable, which are typically 7-wire strands, parallel wires, or bars.) No. Questions Bridge No. 1 Bridge No. 2 4-1 4-2 4-3 4-4 4-5 4-6 4-7 4-8 4-9 4-10 4-11 Bridge name and location Year built Main span length (ft) Type of main tension element (MTE)? (7-wire steel strand, steel wire, steel bar or threadbar, rope, helical lock-coil strand, other) Coating/treatment on main tension element within free length of cable? (bare, greased-and-sheathed, epoxy-coated on outside only, epoxy-coated inside and outside, galvanized steel, stainless steel, other) Are the coatings/treatments on main tension element discontinued or removed within the anchorage zone? (yes, no, not known, not applicable) Type of grout used? (grout not used, cement-water, cement-water- admixtures, commercial pre-packaged grouts, not known) Are filler materials used in the anchorage zone? (yes—grout, yes— grease, yes—other, no filler, not known) Type of anchorage? (wedges, conical socket with wedges, cylindri- cal sockets with wedges, “Hi-Am”-type, other) Do cables go over “saddles” on the pylons? (yes, no) Type of cable sheathing used? [HDPE with PVF (Tedlar®) tape, UV-resistant HDPE, UV-resistant HDPE with spiral on surface, HDPE with dimples on the surface, steel pipe, no sheathing, other]

70 4-12 4-13 4-14 4-15 4-16 4-17 4-18 4-19 4-20 4-21 4-22 4-23 4-24 4-25 4-26 4-27 4-28 4-29 4-30 Have rain–wind-induced cable vibrations been observed on this bridge? (yes, no, not known) Have MTE corrosion problems been noted? (yes, no, not known) Do cables have neoprene rings near the top and bottom anchorages? (yes, no, not known) If there are neoprene rings on the cables, have there been any reports of movements of the rings out of their positions? (yes—due to loosening of retainers, yes—due to shearing off of retainers, yes—due to other reasons, no, not known, not applicable) Has moisture been found in any of the internal components of stay cables such as the bottom anchorage areas? (yes, no, not tested, not known) Has fatigue of MTE or other components of stay cables been observed (yes, no, not known) Do the cables have viscous dampers installed at deck or tower levels? (yes—from the beginning, yes—retrofitted to correct vibrations, no) Do the cables have cross cables installed between them? (yes—from the beginning, yes—retrofitted to correct vibrations, no) Do cables have other dampers (other than viscous or neoprene rings) to control vibrations? [yes—tuned mass dampers, yes—other dampers (please specify), no, not known] Has cracking of the cable sheathing or sheathing connections been noted? (yes—sheathing, yes—connections, yes—both, no, not known, not applicable) Has cracking or misalignment of the guide pipes been noted? (yes— cracking, yes—misalignment, yes—both, no, not known, not applicable) If there is protective tape wrapped around the cable sheathing, have there been reports of deterioration of the tape? (yes—minor damage, yes—moderate damage, yes—extensive damage, no, not known, not applicable) Have any problems associated with neoprene boots been noted? (yes, no, not known, not applicable) Types of non-destructive tests that any of the cables on this bridge have been subjected to? [magnetic, X-ray, ultrasonic, vibration- based force measurements, other (please specify), not performed, not known] Types of sensor-based long-term monitoring performed on the cables? [acoustic wire break detection, vibration monitoring, force measurements, other (please specify), not performed, not known] Have the cables on this bridge (or any of their components) been repaired? [yes (please explain), no, not known] Has the sheathing been partially removed on any of the cables to examine condition of grout (if applicable) and/or the MTE? (yes, no, not known, not applicable) Can the strands or cables be replaced if needed? (yes, no, not known) Do you have an inspection and maintenance manual for this bridge? (yes, no, not known)—If yes, we would appreciate receiving a copy of this manual for the purposes of this synthesis report. No. Questions Bridge No. 1 Bridge No. 2

71 5) Based on your experience and in general, do you believe that the current inspection, testing, monitoring, and repair meth- ods available to you for stay cables are effective and adequate? • Yes • No • Not known 6) Please comment on the effectiveness of any non-destructive test methods for inspections of stay cables that you may be familiar with. These methods include (but are not limited to) ultrasonic testing, magnetic inspections, laser-based force measurements, X-ray imaging, etc. If possible, please comment on issues such as practicality, cost, duration, impact on traffic, and any other factors that you consider important. 7) Please comment on the effectiveness of any cable vibration control measures that you may be familiar with. Examples include installation of cross cables, viscous dampers, neoprene rings, etc. 8) Please comment on the effectiveness of any sensor-based long-term monitoring systems for stay cables that you may be familiar with. Examples include acoustic monitoring, vibration monitoring, force measurements, strain measure- ments, etc. 9) What would you recommend that the cable suppliers incorporate into their systems to make cables more accessible and inspectable? 10) Do you believe that an up-to-date resource such as a national database of information on stay cable inspection methods, repairs, and testing would be a useful tool? • Yes • No • Not known 11) What do you see as the single most important problem in stay cable maintenance? 12) Please comment on any other methods for inspections, testing, monitoring, and repair of stay cable (including conven- tional methods) that you have found beneficial and are not listed above. Additional comments? We appreciate the time you have taken to provide this information and thank you very much for your help with this important undertaking.