14. starptautiskā konference 2012 - Latvijas Jūras akadēmija

Proceedings of 14th International conference „Maritime Transport and Infrastructure - 2012”Maintenance of port structures is a regular and consequent activity. It includes proper andperiodic inspections of technical condition of a structure which is the basis for planning and carryingout required repair or reconstruction. Implementation of maintenance managing program provides toavoid expensive repair works or early disposal of a structure. It is also one of the main procedurewhich helps to avoid failures.Such maintenance managing programs are being implemented in the Baltic Sea region by portauthorities of the Port of Tallinn (since 2001), the Port of Klaipeda (since 2003) and the Port ofHelsinki (since 2004). GT Projekt AS (GT Corporation), being a long-term and reliable partner ofthese ports, together with other private companies, is also involved in these programs as a consultantwhen doing inspections of maritime structures and as a contractor for carrying out repairs andreconstruction.2. Repairing of Port Structures. GT Corporation Experience in the Baltic Sea RegionNot all defects need to be repaired with the same urgency. Prioritization of defects for repairare to be assigned by inspectors while preparing an inspection report. Guidelines for the inspectors tofollow during the field inspections of all the types of quay structures as well as for interpretation of theinspections’ results are established in RIL 236-2006.For owners with multiple facilities requiring repair, a prioritization scheme that considers thestructural condition, functional condition, and importance of the facility to the owner’s operation arevery useful. That is why all the inspection reports issued by GT Corporation contain such prioritizationrecommendations as well as recommendation for the repair method to choose, whereas safetyoperation of a structure is always the main criteria.Particular repair methods have to be defined considering repair objective, repaired structuretype, degree of structure damage or deterioration, environmental conditions and customerrequirements.Results of inspections of maritime structures carried out by GT Corporation during over 20year period show that more severe damages are observed at the zone of the variable water level and inthe splash zone. After the first damages occur a further destruction is highly accelerated.The repair of port structures under the sea water level, and particularly in the tidal or splashzone, provides many difficulties occurring during preparation of the deteriorated structure for repairand during the repair itself. Usually such repairs could be performed using divers and underwaterrepair methods, although the quality of such works, as well as the checking of quality, efficiency anddurability is not satisfactory. Among the disadvantages mentioned above non-usage of a structure for along period is also a significant negative factor.For repair and protection of quay structures in the underwater zone and in areas of difficultaccess GT Corporation has worked out and implemented new technologies. Technical solutions arebased on use of special underwater equipment – a hermetic chamber – that facilitates implementationof works in the underwater zone in the air-dry conditions without suspension of the quay structureoperations.A hermetic chamber is a floating metal structure with a special shape which is installed closeto a structure and makes it possible to create near the repair site a working area isolated from the waterbasin. After installation of a hermetic chamber, water is pumped out of the working area and all worksbelow the waterline can be carried out in air-dry conditions.Repair methods with use of hermetic chambers are developed for quay structures of differenttypes and objectives. Hermetic chambers are used for:- repair of reinforced concrete piles and piles joints with superstructure elements;- repair and strengthening of reinforced concrete slabs and capping beams;- corrosion protection and repair of steel piles and steel sheet piling walls;- sealing joints and repair of walls in blockwork construction and box caissons;- strengthening of quay walls by installation of additional anchor ties.34