VII International forum
“Marine Industry of Russia”
Hotel complex
«President-Hotel»
Department of affairs of the President of the Russian Federation

Moscow, 24, B.Yakimanka Str
24-25 May 2017
 
Forum bulletin


More on hydraulic structure repair

Hydraulic structures (HS) are all kinds of constructions used at water resources for their protection from harmful effects. In marine and inland industry, these first of all comprise port constructions (approach channels, moles, berths, piers, wing and vertical bank protections), bridges, ferry crossings, etc.

Repair of hydraulic structures can be running and overhaul, and it is to provide necessary service time of the construction and its structural components, regain operational and technical characteristics of worn-out HS, maintain their operational characteristics as well as to bring them in line with modern requirements. Repair decision is made basing on the regular HS inspection.

HS inspection comprises:

  • examination of constructions in surface and underwater areas;
  • estimation of member location by means of special and geodetic measurements;
  • estimation of mechanical condition of fabrication materials by applying NDE, and, if necessary, structural performance testing of HS components and their members.

Basing on the inspection results, an enterprise having performed the inspection issues a final report which usually refers to necessary repair operations, their scope, technology and timing. Project and cost estimating documentation is prepared. All HS engineering survey and repair operations are to be performed only by licensed entities. On the repair stage, safety requirement compliance of the construction is estimated. Among other issues, it is performed “by drawing up acts commissioning acceptance act and issuing a commissioning certificate” (Federal Law on Safety of Hydraulic Structures).

Repair of Hydraulic Structures may comprise such operations as:

  • bottom dredging;
  • assembly and disassembly of engineering structures;
  • overwater and subaqueous concreting;
  • HS metal structure repair including underwater repair (metal welding, cutting, corrosion removal, antirust coating and metal structure assembly).

In particular, berth repair comprises practically all types of HS construction operations:

  • driving of sheet piles, if berth expansion is necessary (the most expensive berth repair operation);
  • if it is not necessary, sheet pile wall sealing and ground-impenetrability restoration are performed;
  • sheet pile cutoff sealing;
  • metal structure fabrication and assembly;
  • concreting;
  • utility and coating arrangement;
  • mooring drifter repair;
  • replacement of land-fasts, knights, etc.

Features of Hydraulic Structure Repair and New Trends

In service, hydraulic structures themselves, their materials, members bear various loads and are exposed to aggressive environments which gradually decrease initial operational characteristics. Besides, HS lifetime is twice as long as that of ships and port facilities. The majority of berths of the former USSR which were built for ships then considered to be state-of-the-art has become obsolescent by now. According to experts, about 80% of such constructions in our country need overhaul repair or modernization due to deterioration and necessity of serving new ships of ocean-going class.

The most acute problems in HS repair are concrete structure restoration and damp proofing. Here, some solutions are applied selected by the age of concrete of the construction and fluid filtration method. For example, application of state-of-the-art penetrant damp proofing in cross-flow filtration may jeopardize the situation and cause destruction of metal fittings. It also should not be applied for “old” concrete due to low content of calcium ions. But such solutions are feasible in restoration of damp-proofing of new constructions.

Reinforced concrete structure restoration by injection of special solutions into the body of the structure is a relatively new method in our country. Depending on its material as well as type and size of a damage, cements, hydro-active foam polymeric compositions, resins, hydrophilic gels and high workability silicone oils can be applied. Injection technology significantly cuts down repair expenses and work content, so more and more enterprises apply it.

Domestic researchers and developers do not forge ahead, too. RusHydro Russian Research Hydraulic Engineering Institute named after B. E. Vedeneev developed an approach for construction concreting by means of new generation cast concrete. These compounds include dispersed and ultra-dispersed active fillers featuring with flowability, mixing, remolding effort, which ensures high grade matured concrete. The same institute developed and introduced the method of restoration of anti-piping collector ditch integrity which does not require to perform complete inverse filter refill. In this case, the repair can be performed without unloading supporting structures. There are also many other developments.

 
 
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