Bulletin of the Transilvania University of Braşov • Vol. 9 (58) - 2016 Series I: Railways, Roads and Bridges Section EFFICIENT BRIDGES SOLUTIONS IN ROMANIA C. DIRSCHL1 S.B. KAISER2 A. BARATKI3 E. PETZEK4 Abstract: An important factor within Europe’s development process is the transportation system. “Design and build” projects allow the implementation of efficient, economical and also modern structures. The present paper presents a quick overview of new designed and executed structures in Romania. These bridge solutions combine many important aspects: reduced costs, fast and simple erection, modularity, durability and robustness, low maintenance costs and an appealing aesthetical aspect. Key words: integral bridges, semi-integral bridges, modern bridge solutions, frame structures, composite dowels. 1. Introduction durability and robustness, low maintenance costs, aesthetic aspects. Many of the new investments in the land The current trend aim is to develop communication system are assigned by concepts and technologies that simplify tender projects in form of „design & build” and streamline as much as possible the and in this way joint ventures between existing solutions on the market, thus execution companies and structural various research programs were developed engineering offices are given the in the past years in which have been possibility to build whole road sectors in involved both the private business and the an economic advantageous manner. This state. A step forward to increase the assignment method permits the newly competitiveness of the bridges, the developed, innovative and economical modular concept was development. By solutions to be used in Romania as well. eliminating the bearings and the expansion The current paper presents a quick joints leads as much to a simplification and overview of a series of efficient solutions acceleration of the construction phases, but of integral bridges from Romania, that take also to a reducing of the maintenance costs into account several important aspects for those structures. from the point of view of the builder and In the design and construction of bridges, also from the administrator, these are questions of sustainability, maintenance reduced costs, simplicity of the and durability become more and more construction details – modular systems, important for European road 1 Faculty for Civil Engineering, University Politehnica of Timisoara. 2 Faculty of Architecture and Urbanism, University Politehnica of Timisoara. 3 Faculty of Civil Engineering, University Politehnica of Timisoara. 4 Faculty of Civil Engineering, University Politehnica of Timisoara & Structural office SSF-RO Ltd. 196 Bulletin of the Transilvania University of Braşov • Vol. 9 (58) - 2016 • Series I administrations in addition to safety and serviceability issues. From this perspective, integral abutment bridges turn out to become highly attractive to designers, constructors and especially road administrations. The main reason for this is Fig. 1. Integral structures on Euro- that they tend to be less expensive to build, banknote easier to maintain and more economical to own over their life time. The first lot of motorway Orăștie - Sibiu, All these needs have been proven to be which is part of the IVth pan-European met by integral abutment bridges, as this corridor located near to the town Orăştie bridge type not only lowers production and and the Mureş River and its confluents, maintenance costs but reduces economic with a total length of 24.110 km, where 27 and socio-economic costs as well. bridges were included, represent the first − The superstructure can be designed example in this sense. On this section all quite slender, which decreases the structures are being designed and executed construction height and the earthworks as bridges with integral abutments, except respectively. This leads to a decrease of the viaduct from km 1+240, with a total material, fabrication, transport and length of 240 m, which is a semi-integral construction costs. structure. As a consequence, only two − Frame bridges allow for the pieces of expansion joint equipment and elimination of the middle support. This eight bearings were used for the whole simplifies the construction of the bridge motorway lot. This motorway lot can be without essential interference of the traffic considered a European premiere, having under the bridge, as the road has not to be only integral or semi-integral bridge closed. structures. Due to the absence of bearings and The solution called BFT® (Beton joints, the maintenance costs can be Fertigteil Träger – prefabricated concrete decreased significantly. girder) was adopted for motorway bridges as well as for overpasses with one or two 2. Applied Solutions spans of 36.5 m. These are integral structures, having a frame as static system, An important step in the construction of and use prefabricated prestressed concrete efficient bridges was done in our country girders. In addition, precast concrete slabs beginning with 2011 through reusing of are used in the interspaces between the integral structures. At these types of prestressed girders. structures the abutments and the piers are monolithically connected to the superstructure and in this case a clear distinction between the superstructure and the infrastructure of the bridge is not possible. The integral bridges have a very long tradition; arch-like bridges have been erected for over 2000 years. Practically nowadays the frame structures are the so Fig. 2. 3D calculus model called “old arch bridges”. DIRSCHL, C. et al.: Efficient bridges solutions in Romania 197 The concrete slab is casted in-situ and represent real alternatives to massive only a minimum of casings are needed. concrete bridges. The usage of Also, due to the frame static system no prefabricated steel-concrete composite consumables are used – no bearings and no beams PreCoBeams and the modularity of expansion joint equipment. The foundation the structures lead to large erection speeds. mode is elastic using drilled piles with The high degree of prefabrication reduces large diameter. the possibility of unexpected situations on site and offers execution simplicity. The steel performance and its optimum use of this material determine cost indices that rival the classical concrete solutions. The reduced weight of the prefabricated composite beams offers advantages both in the transportation as well as in the manipulation efforts and contributes to the Fig. 3. Executed integral concrete success of modern composite bridges. motorway bridges and overpasses The introduction in the year 1998 of the prefabricated composite beams VFT® An important integral bridge is the three (Verbundfertigteil – Träger) was a success span (32.00m + 32.00m + 32.00m) and proved a very good quality and motorway viaduct at km 9+405 over the efficiency of the constructive parts (the Cugir River, at an angle of approximately main girders) which are entirely made in 57º between the motorway axis and the the workshop. At present a few thousands flow direction of the river. Taking into of such examples exist in Europe. Through consideration the long length for an a sustained and systematic research entirely integral motorway bridge, the activity a step forward was made regarding structure is a remarkable engineering the development of efficient and achievement and as well a premiere. The innovative solutions for composite bridges superstructure aligns in cross section 7 by creating an efficient connection prestressed girders for each deck. Between between the steel and concrete structure. the girders, at the upper flange, The efficiency consists in the elimination prefabricated reinforced concrete slabs are of the classical Nelson type connectors and added. implicitly of the upper flange of the steel section, and creating the so called composite dowels by cutting the steel web according to a predetermined contour. Fig. 4. Motorway viaduct at km 9+405 over the Cugir River (2013) On the other hand, steel-concrete composite sections become more and more Fig. 5. VFT® solution for composite popular solutions in many countries and bridges 198 Bulletin of the Transilvania University of Braşov • Vol. 9 (58) - 2016 • Series I The solution was used in case of two of aspect as well as a pleasant aesthetic aspect the Orăştie – Sibiu Motorway, lot 1, too. overpasses. This is the first time in Generally, at bridge conferences, Romania when the connection between extraordinary structures regarding the size, steel and concrete is made through the difficulty degree or the aesthetic aspect composite dowels and it is also a world are presented. A new construction solution premiere for a composite bridge not to for steel–concrete composite bridges was have an upper steel flange and studs. Both applied in Romania for two motorway passages have one opening and are oblique bridges, structures which do not stand out (approximately 70°), integral structures because of their size or because of their and they use four steel-concrete composite complexity. But the VTR® solution is beams approximately 40 m long. The characterized by premises, which could be composite dowels require a cutting remarkable for beneficiaries as well as for geometry on the upper part of the steel contractors: a steel–concrete composite using a special form adapted to the girder system can be realized economically requirements given by fatigue, and in short time; the use of open ditches reinforcement and concrete. Thus, a which can be easily integrated in the connector