PSI - Issue 13

Vera Vujović / Procedia Structural Integrity 13 (2018) 1901 – 1907 Vera Vujovi ć / Structural Integrity Procedia 00 (2018) 000–000

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The bridge is large in size, huge quantity steel and concrete are used for its construction, it has an old monitoring system, it has specific equipment, it has very high pillars, it is exposed to constant strong winds, it is located in seismically active area. Maintenance of the bridge requires extremely high funding and special attention in the planning and organization of all activities. Taking into account, previously stated limitations and that the budgetary funds for maintenance are not sufficient, anticorrosion protection was last renewed in 1985, and the monitoring was carried out in 1989. Monitoring of the bridge and terrain could only be carried out by an authorized institution, and as this type of service is very expensive, the consequence of the economic crisis has resulted in a delay in impossibility of realization. I spent more than a decade working on maintenance, and I paid special attention to researching the possibilities for creating a sustainable bridge maintenance and monitoring model. The Preliminary Design envisages a monitoring model that involves the engagement of an outside authorized institution and rental of equipment, and would be carried out periodically. The concept that discussed in this papers focuses on developing a maintenance model through long term planning, where continual monitoring would be in the context of current maintenance, and all equipment is permanently owned by company, including human resources trained to perform monitoring in real time. One of the most optimal solutions for modernizing maintenance of one of the highest railroad bridges in the world is the simultaneous application of SHM and BIM. In separate chapters, a general analysis and a rough estimate of the possible costs of developing the structural health monitoring system of the bridge and BIMwas carried out, where it should be pointed out that it is necessary to perform optimization by special experts, which can greatly further reduce the costs. In case of consideration of the possibility of introducing BIM and SHM, the current maintenance model, which includes current and investment maintenance, should be harmonized with maintenance standards, primarily MEST EN 13306:2017, Maintenance - Terminology in maintenance, etc. Explorations works were carried out by "Geofizika" Zagreb and the Institute for Geological and Geophysical Exploration SRS, Serbia, 1968. Study on the exploration works made by the Bureau of Geology and Geomechanics Institute for designing ZJŽ. Geological explorations showed the geological structure of the terrain (the Jurassic and lime sediments) and petrographic composition (oolitic limestone ovoid shape and grain bonded calcitic cement). The bridge has 6 RC pillars (2 coastal and 4 intermediate), interstices are a cassette cross-section and have two chambers with longitudinal and transverse stiffening at every 8 m. The height of the columns of S1-S6 are: 7,76 66,50-138,50-130,50-50,50. The highest column S3 is 112 m high and along with the foundation is about 140 m. Pillars are (81,20 + 92,80 + 150,80 + 92,80 + 81,20 = 498,80 m). The height from the bottom of the trough to the upper edge of the bridge rail 201,24 m. Continuous grid steel structure is 498,80 m long, 12,50 m high, width 6,50 – 9,00 m and weight 2.601.284 kg steel. The route of the bridge on the bridge is 300 m in the direction, 120 m in the transit curve and ends with a circular curvature of the radius of 300 m. Constant width of 6,5 m from I to IV openings, and in V hole, the width gradually increases up to 9,00 m. The main contractor was GP "Mostogradnja ", and subcontractors" LIK "- anticorrosion protection, "Metalna" and "Đuro Đaković"- suppliers of steel structures. Percentage participation of the Mala Rijeka Bridge in relation to 16 steel bridges: 17.19% length, 30.96% area, 27.56% weight. 590 sleepers on the open pavement part (Lok = 363,80 m), 231 sleepers in the closed railroad part Lzk = 135 m), Fig 1. Building materials are shown in Table 1.

Fig. 1. Mala Rijeka Bridge (a) sketch drawing; (b) longitudinal view.