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 Provision of necessary state supports (foundations, piers, pylons) for safety operation of the bridge 2 Detection of various defects of underwater bridge elements 3 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.

At fluctuations of water level in the reservoir occurs alternate wetting and drying of the surface of the elements of the bridge.

Increases its disposal and may lead to irreversible deformation structures.

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

Stages

2)

Cleaning and surface preparation processed elements of bridge support

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 .