PSI - Issue 13

Vera Vujović / Procedia Structural Integrity 13 (2018) 489 – 495

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Vera Vujovi ć / Structural Integrity Procedia 00 (2018) 000–000

6. Study on bridge condition and damages Upon completion of the research, deterioration on the surfaces of the foundations that significantly affect the load capacity was registered. Water leaking through the bridge plate influences the appearance of vegetation and leads to the decomposition of mortar joints of masonry, spreading of joints and separation of stone. The biggest damage was found on the seventh pillar. Constructive and other analyses in the framework of the Study on Bridge Conditions and Bridge Rehabilitation Design were made on the basis of research works performed for the purpose of identification: soil properties, forms of supports and construction material. The recording of all bridge surfaces was done by the laser scanning method and the 3-D model was obtained on November 18, 2008. It was found that the changes were due to changes in the water level and the flow of the Drina river after the construction of HPP Bajina Bašta from the downstream side of the bridge and the HPP Višegrad on the upstream side. The river bed profile has undergone some changes in the places where the foundations have come out considerably. Constructive analysis has shown that increased tensile stresses in the foundations of the bridge were exposed to loads of their own weight and hydraulic load. The study of the state of the bridge provides information on a comparative evaluation of structural analysis studies done using two softwares (LUSAS and SAP 2000). Modeling and constructive analysis was done in software programs LUSAS and SAP 2000. LUSAS software: The highest tensile stress values were obtained in the damaged base A6 with richly decorated stele and it is 1.05 MPa. SAP 2000 Software: In all analysis, the pressure levels are compared to the acceptable stresses, and no problem of overpressure strength is noticed. For massive models, the SAP2000 software is not suitable for use. Earthquake Analysis - European Seismological Commission has prepared a map of seismicity of Bosnia and Herzegovina. Soil acceleration in the event of an earthquake is about 0.2g. This corresponds to the 3 rd degree of the earthquake zone in Turkey, according to the maximum acceleration of soil that will occur during a possible earthquake. The first phase of works began in 2013, and included rehabilitation of the foundations of the bridge by creating stone embankments, repairing the base walls by injecting a hydraulic mortar. The works were carried out in the period when the HPP "Višegrad" reduced the inflow of water and its quantity in the trough was at a minimum. The second phase of works continued in 2014, and included the conservation and restoration of a part of the bridge located above the water, the access ramp of the bridge on the left bank of the Drina (as well as on the right, on the retaining wall below the hotel Višegrad), as works on paving and electric lighting bridge. The deposits on the stone surfaces were removed by a low pressure water jet (1,5 bar) and a soft plastic brush without damaging the patina and joints. 7. Maintenance and monitoring of the bridge The bridge and band 100 meters long and upstream are in the 1 st permanent protection zone. Maintenance includes all measures and procedures that are taken during the service life to fulfill the target sustainability, so that the necessary level of safety and usability is ensured. The maintenance concept in accordance with EN 13306:2017 Maintenance - Maintenance Terminology is defined as a combination of all technical, administrative and management activities throughout the life cycle of an object, aimed at retaining or restoring a condition in which it can fulfill the required function. Generally defined maintenance coverage: inspection, preventive maintenance, repair and improvement of basic procedures. Quality planning and organization are basic activities that affect the success of maintenance management. Types of maintenance according to EN 13306:2017 Maintenance - Maintenance Terminology are: preventive, predetermined, condition-based, predictive, corrective, directly corrected, planned, remote control, on-site, by operator. Inspection based on inspection plan. Maintenance management according to EN 13306:2017 Maintenance - Maintenance Terminology defines all management activities that determine: maintenance objectives, strategies, responsibilities, implementation (planning and maintenance control with economic improvement). Maintenance management is carried out at three different levels: the formulation of a harmonized strategy, planning and implementation. After the works were completed, defects and damage were registered: damage to the base station A11 (right side downstream); damage to "intrados" (bottom line of port) on port L10 (downstream); problems with waterproofing, drainage, drains, registered humidification and leakage on the surfaces of arches and columns; bio deterioration (occurrence of moss and algae on the surfaces of stone, concrete and mortar joints) of arches, pillars and foundations; by raising the riverbed of the Drina River, the permeate power is reduced in the riverbed between the arches of the bridge (remark of the representative of HPP Bajina Basta and HPP Višegrad within the technical reception); a