Underwater inspection of bridge by Kokodeev A.V., Ovchinnikov I.G History 15 December 1967 - the accident at the Silver Bridge, USA Silver Bridge Location - West Virginia, across the Ohio river Field of application - car Total length - 443 m, the number of spans -3 The type of construction is suspension bridge, material - steel Open - 1928, close - 1967 The main causes of the collapse The increased load from the increased traffic flow. Consequently, the deformation of one of the suspension rod. Material fatigue and abundant corrosion of individual elements of the bridge Consequences 1968 - the initiative of the US Congress about the introduction of new state standards inspection of the condition of bridges Requirements Every state should carry out periodic inspections inspections on bridges, in their territory, with a maximum interval between inspections in 24 months. Inspectors must have the necessary qualifications on this issue. Should be developed and training of inspectors. Schoharie Creek Bridge Collapse 5 April 1987 - the destruction of the bridge Schohari Creek, new York, USA The main causes of the collapse Abnormally large amount of precipitation, and rich of snowmelt resulted to extensive scour. Inspections and maintenance of the bridge were not conducted properly, certain errors designers. Underwater inspection of bridges 1 2 3 Provision of necessary state supports (foundations, piers, pylons) for safety operation of the bridge Detection of various defects of underwater bridge elements Prevent any possible damage of structural elements of constructions with the help of timely action What check? Cavity (cracks) in stone / concrete masonry Detection of weathering of masonry Damaged / missing elements of masonry Checking the condition of joints and seams What check? Assessment to exposure of reinforcement and rebar Traces of rust, chips, abrasive wear, crushing in concrete elements Checking the status of the steel constructions (pipes, steel caisson and screw piles, steel caissons) Assessment of ground deformation in support parts bridge construction Examples of failures and defects of the bridges elements Diving as a way of underwater inspections The types of diving works Scuba diving: the diver is equipped with autonomous device for air supply The types of diving works If necessary, a long and detailed inspection, apply such technologies diving, in which the diver is connected with a special cable with equipment on the surface. Norm and safety for divers The minimum age diver 18 years of age, maximum age of 45 years Fitness by doctor in last six months Good physical condition, ability to withstand stress Free from cardiac and ear problem Not addicted to alcohol and excess smoking Going special tests to work at the depth Knowledge of special signals when diving Ability to work in zero visibility conditions Type of underwater inspection Sonar (SOund Navigational And Ranging - sound navigation and ranging) uses sent and reflected sound waves to detect underwater objects and distance measurement. ROV devices (remotely operated vehicle). Relevant for large depth of research, or when environmental conditions when it is impossible to adequately conduct the underwater inspection of the bridge. ROV devices Teamwork divers and ROV Rov’s technologies in some cases can apply well in advance of diving divers to collect information on defects structures, the formation of scour, acting on the support, and also about the clusters of construction and other debris, which will facilitate and ensure the safety of the divers. ROV’s devices can serve as a navigator, guiding divers to certain areas. Example of application May 2008, floods in the Midwest, USA. Photo of the Cedar Rapids, Iowa. The impact of the floods on the bridges With the rise of water level in the reservoir water penetrates through the gaps between elements of the walls and saturates soil backfill. Increases its disposal and may lead to irreversible deformation structures. At fluctuations of water level in the reservoir occurs alternate wetting and drying of the surface of the elements of the bridge. Leads to the development of the corrosion processes. Example of application Images of underwater parts of the supports, received with the use of sonar «Kongberg Mesotech». The list of methods and devices for underwater inspections Sounding methods - to control scour Magnetic particle research – to detection of cracks on the surface of parts of supports produced in the framework Magnetic recognizer rebar– to determine rebar location Ultrasound system- to the check uniformity of filling and compaction of the concrete Radiography – for detection of internal defects Procedure for defects elimination in the underwater part of the bridges elements 1) Initial inspection, filming future work places 2) Cleaning and surface preparation processed elements of bridge support Stages 3) Evaluation of terms and cost of works 4) Getting work start, formwork/fixing worksheets 5) Micro-concreting and finish the job Conclusion Systematic and scientific aimed underwater exploration is very important for the safe operation and management of bridge construction. A considerable number of collapses and accidents occurring on bridges can be avoided by timely conducting underwater inspection and examinations. Having familiarized with the experience of foreign scientists in the solution of these questions our specialists can speed up the process of development of the domestic technology of underwater bridges inspection. REFERENCES 1. Podvodnoe obsledovanie transportnyh sooruzhenij / V.V. Sokolov, P.P., Nikitin P.P. Izd-vo «Transport», 1970. 152 s. 2. Obsledovanie, remont i usilenie osnovaniy I fundamentov transportnih sooruzheniy I.G. Ovchinnikov, A.A. Shein, A.A. Piskunov, uchebnoe posobie, Kazan, izd-vo KGASA, 2005. -300s. 3. K.Simon Mohd. Bakhsh, A.Raj Kumar Underwater inspection of bridges illustrated with case study, 2010, P. 35 4. Terence M. Browne, P.E.; Thomas J. Collins, Michael J. Garlich, John E. O’Leary, Daniel G. Stromberg, Katherine C. Heringhaus Underwater Bridge Inspection Collins Engineers, Inc. // llinois, 2010, P. 224. 5. Daniel G. Stromberg, Collins Engineers, Inc New advances in underwater inspection technologies for railway bridges over water // Chicago, Illinois, P. 29 6. Leshko Brian J. Revised National Bridge Inspection Standards (NBIS) // Structure magazine, December 14th, 2004 USA P. 45-47 7. Site of U.S. Department of Ttansportation. Federal Highway Administration.- Electronic data.- Washington ,2014. -http://www.fhwa.dot.gov/ 8. Wikipedia.- Electronic data.- 2014.-http://en.wikipedia.org 9. Site of the Recorder magazine.- Electronic data. ttp://www.recordernews.com/news/04052012_bridgetimeline.