The bridge carries the existing PATHE motorway over Pinios river at Tempi and has a total length of approx. 210 m. It consists of 5 spans with theoretical lengths 40,72+72,06+40,63+25,0+30,77=209,18 m. The bridge deck is 14,0 m wide and comprises an 11,0 m wide carriageway and two footways each 1,50 m wide.
Spans consist of prestressed concrete twin-box girders and simply supported beam grillages with high precast prestressed concrete I-beams. Transverse prestressing is also applied to the deck slabs.
At M1 and M2 the inclined columns are supported on vertical wall-type concrete piers.
Piers M3 and M4 are four- and three-column frames, respectively. Pier M1 is founded on prestressed concrete driven piles., while piers M2, M3, M4 rest on spread foundations.
Abutment A1 (at the south bank) is a multi-cellular box structure with total plan dimensions 10×14 m, while abutment A2 (at the north bank) is a typical gravity wall with two relief shelves.
Bridge investigations have detected significant defects that reduce both the bearing capacity of structural elements and the durability of the entire structure. Furthermore, analytical checks have shown that the existing bridge structure is not capable to resist either the increased traffic loads or the seismic loads prescribed by current codes.
Proposed interventions aim to mitigate these structural deficiencies and they can be divided into three categories:
1. Strengthening interventions aiming to increase the resistance of the structure against vertical service loads.
• Construction of a new strengthening slab 12 cm thick on top of the existing deck slab.
• Strengthening of the precast beams by means of external prestressing.
• Shear strengthening of the box webs by means of externally installed vertical prestressed steel bars, in combination with transversal steel girders attached to the outer surface of the box bottom slab.
• Replacement of all bridge bearings with new elastometallic bearings.
2. Strengthening interventions aiming to upgrade structural capacity against horizontal seismic loads.
• In the transverse direction, strength and stiffness of the existing piers is improved by the addition of steel bracing systems and lightly reinforced R/C jackets so they can resist the increased seismic loads.
• In the longitudinal direction, the retrofit proposal aims to modify the load path through which the longitudinal seismic component is transferred to foundations. The proposal comprises of the enforcement of superstructure continuity by cancelling intermediate joints between spans through the construction of continuity slabs and the addition of a new, stiff Λ-shaped R/C frame at the location of pier M3, connected to the continuous superstructure by means of shear key bearings.
3. Repair measures to restore durability of the bridge.
Scale: < 10 km
BW7 Valley Bridge
In the context of the upgrading project of the National Road B29 at Stuttgart – Aalen, bypassing the community of Mögglingen, about 65 km west of Stuttgart in Germany, was suggested. As part of the overall project, the BW7 valley bridge over river Lauter was recently constructed and delivered to traffic. METE SYSM participated in the preparation of all the individual stages of the detailed design study in collaboration with the design office Harrer Ingenieure for the contractor of the project Wolff & Müller and provided support to the contractor during its construction with over 100 drawings in the final stage.
The bridge with increased technical and aesthetic requirements was designed with the highest level of detail, also incorporating a very large number of Technical Specifications (Richtzeichnungen BAST) applied for roadbridges in Germany.
The bridge consists of two separate branches (North and South) with an intermediate joint of 10cm. The superstructure is continuous with seven spans (271,5m total lengh on the bridge axis) made of cast in-situ prestressed concrete. Each separate branch was constructed in 3 stages (2, 2 & 3 spans) starting from the eastern abutment with construction joints at 20% of the span.
In plan, the bridge horizontal alignment is on a circular arc with a radius of 1.350m, while the red line is straight, with a slope of 0,50%, at a height ranging between 8,0 and 10,0m from the natural terrain. The piers which have a “peanut” cross section with external dimensions of 3,8×1,65m and clear heights of the ranging between 6,0 and 8,0m, are founded on pile caps. The superstructure rests vertically on bearings either free sliding, guided (longitudinally free) or fixed (transversely and longitudinally), with expansion joints only at the abutments.
The cross section of the girder is a beam-slab with constant height of 2,0m, web width of 3,8m, and a total slab width of 14,25m (upper flange) with a 4% transverse inclination. The long arising cantilevers at either side (5,0 ÷ 5,5 m) are supported at almost every 4,0m with oblique steel buttresses of hollow circular cross section. The total width of each branch of the highway carries one-way traffic of 2 traffic and 1 emergency lane and sidewalks on both edges. On the sidewalks safety barriers, street lighting poles and curved sound curtains of special aesthetics are provided. Also, insulation of the deck with a special membrane and drainage of the deck with longitudinal and vertical drainage pipes is provided.
Eastern Inner Ring Road
In the context of the upgrading project of the existing Eastern Inner Ring Road of Thessaloniki, the construction of an Elevated Expressway (Flyover), next to the existing ring road (between I/C K5 and I/C K10) at an overlying level is suggested. The project will significantly decongest the existing ring road, which will also be upgraded to serve local and heavy traffic.
The entire project is extremely complex and technically demanding, judged as “Special and Important at National Level” planned to be constructed with a Public-Private Partnership Contract. METE SYSM has prepared the preliminary studies of the technical works for the whole project, which are already approved and participates in the preparation of the predesigns.
The most important and also special part of the project is the construction of an Elevated Bridge with a total length of 4.000m between I/C K6-Neapoli and I/C K8-Triandria. At the predesign stage, our office is responsible for the first section of this bridge (Bridge T9a) with a total length of 2.000m between I/C K6 and I/C K7, next to the existing Ring Road on the “Sheikh-Shu” forest side. In plan, the bridge alignment moves on straight lines along with circular arcs (R=1.100–1.200m) and corresponding transition curves. In elevation, the red line exceeds that of the adjacent ring road and the natural terrain usually by 7,0 – 8,0 m, but also 11,0 – 12,00 m, except for the areas of two valley bridges with red line elevation 25,0 – 30,0m above the ground.
The box-shaped cross-section is 2,5 m deep with a total width of 22,2 m, carrying bilateral traffic (2+2 lanes and emergency lanes). The net traffic width is 9,7m in each direction with an intermediate rigid safety barrier. At the two edges of the section, safety barriers, sound curtains and lighting poles are provided. The deck is also provided with insulation special membranes and a drainage system with longitudinal and vertical pipes.
Along the 2.000m of the bridge, a total of nine (9) independent substructures are formed, with lengths between 170,0m and 235,0m. The superstructures are continuous, with four to five spans of about 45,0 m and expansion joints at the ends of the subsections. The piers are single-column, of variable length, founded on shafts. The superstructure rests on bearings in the piers where expansion joints are provided and is monolithically connected to the rest of the piers, forming a case of semi-integral bridges.
Railway Viaduct T12
It is about a seismically isolated railway viaduct with a total length of 800,0m, a width of 13,9m and a maximum pier height of 38,7m. The superstructure of concrete is continuous, single-cell box girder, longitudinally and transversely prestressed, constructed using the launching formwork system (“movable scaffolding”). Two single-action fluid viscous dampers at each abutment and pier to deck connection via lead-rubber bearings (LRB’s). Pile foundation.
Interchange K16
This project concerns a detailed design for the operation of K16 Interchange (without the Pontou overpass), by forming roundabout at the intersection of Internal Ring road of Thessaloniki and Pontou Str. And k16 ramps, until the completion of all road works and detail signage design for the whole project, with the roundabout.
The project relates to a two-lane and an auxiliary lane, Motorway 2.5 km long, 4.5 km long junction section, 800 m long interventions on a two-lane Ring Road, and a multi lane roundabout with five accesses.
Road Viaducts G2
Road viaducts carrying two independent branches of motorway, with a total length of 350m, a width of 14,2m each, and a maximum pier height of 58m. Continuous superstructures of prestressed concrete single-cell box girder of variable depth, rigidly connected to the piers, constructed with the balanced cantilever method. Bridge piers are founded on cylindrical shafts.
Road Bridge G4
In the context of the upgrading of the Northern Crete Road Axis (BOAK), Bridge G4 from CH.5 + 710.99 to CH.6 + 150.00 (Gournes – Hersonissos section, Heraklion Prefecture) was recently constructed and delivered to traffic. METE SYSM prepared the final study of the project and provided support to the Contracting Consortium during its construction. After completion of the bridge, the construction company participated with it in the Concrete Awards 2019, the first awards created to highlight the excellence in concrete projects, in terms of design and construction level, but also functionality, originality, environmental protection, satisfaction of the end customers and users of these projects. Bridge G4 was distinguished by winning the silver award in the Infrastructure Works Section/Subsection: Bridges and Tunnels.
The bridge superstructure is continuous with five spans (total lengh 440,0m on the bridge axis) made of cast in-situ prestressed concrete. The balanced cantilever method was used for the construction with 3,5 to 5,0m long segments. A camber design study to support the contractor at every construction stage was also prepared.
In plan, the bridge alignment moves along a circular arc with a radius of 900m and a straight line after the corresponding transition curve. In elevation, the red line moves in a straight ascending section with a slope of 4,27%, at a height from the natural terrain, ranging from 5,0 to 31,0m, and mostly between 20,0 and 28,0m in the central part of the bridge. The clear heights of the piers are 15,0m, 20,5m and 22,0m . The outermost piers have a twin blade (rectangular) cross section while the central piers have a rectangular hollow section with external dimensions of 4,0×6,5 m. Piers are founded on pile caps.
The single box-shaped cross-section has a height which varies parabolically in elevation, ranging from 3,0m in the central span region to 6,5m in the pier supports. The total width is 13,75m carrying one-way traffic of the right branch of the highway with 2 traffic and 1 emergency lane and sidewalks on both edges. Safety barriers, street lighting poles, insulation of the deck with a special membrane and drainage of the deck with longitudinal and vertical drainage pipes are also provided.
The superstructure is monolithically connected to the four piers, resting on sliding bearings (vertical) along with shear keys (transverse horizontal) at the abutments, forming a case of semi-integral bridge with satisfactory behavior for both vertical as well as horizontal loads, with expansion joints and bearings only at the abutments and with reasonable displacements.