tegetthof bridge graz

initial situation
the new tram alignment over the tegetthoff bridge requires, for structural reasons, a replacement of the existing bridge, which is over 40 years old.
not far from the kunsthaus and mur island, only 150 meters downstream south of the erzherzog-johann bridge, graz will receive a new bridge over the mur river. graz was european capital of culture in 2003 and is a unesco city of design. “unesco city of design” is not a label or image campaign. it represents a lived attitude and an expression of urban culture that regards the conscious design of living space as a central value. the design quality of the new bridge plays an important role due to its central location in the city and its impact on the future development of andreas-hofer-platz.

architectural concept
the existing bridge is barely perceived as a bridge, but rather as an extension of the street space. the goal of the design is to make the new bridge experienced as a bridge and to make crossing the water attractive for all users. this is achieved through the type of construction and the shaping of the bridge in plan and elevation. making the bridge structure visible in the form of two compression arches approximately nine meters high, with net-like suspensions for the traffic surfaces, makes the bridge perceivable from all viewpoints. users of the bridge clearly perceive the crossing when walking or driving.

separation of traffic areas
the traffic area for different users is divided into two zones. while the tram, motor vehicles, and bicycles cross the mur on a gently rising arch, pedestrians are guided downward on two side paths separated from the bridge structure. this special positioning of pedestrian walkways conveys exclusivity and invites lingering and observing the river landscape. the different materials—concrete paving for vehicle traffic and wooden planks for pedestrian paths—reinforce the impression of an independent area. due to the different heights of the two areas in the bridge’s center, improved views of the river are achieved for both vehicle traffic and pedestrians, each enjoying views in two directions. even users of the mur promenade benefit from interesting sightlines through the open spaces above.
separating the pedestrian area from the main bridge allows for a minimal roadway width of 14 meters in the bridge center. to provide more space for cyclists at intersections, the roadway widens toward the supports to approximately 21 meters. thus, the bridge width varies between 14 and 21 meters.

increase of freeboard
by raising the load-bearing structure (compression arch construction with net-like hangers), the supporting cross-section below can be significantly reduced, allowing for a considerably higher freeboard. the lowest edge of the lowered pedestrian area is at 348.60, providing a freeboard of approximately 2.40 meters, 25 centimeters above the HQ 1000. this increased protection against flooding is highly advantageous given the increasing frequency of extreme weather events with heavy rainfall.

material concept
three main materials are used: the load-bearing steel structure in gray-white, pedestrian walkways with untreated wooden planks, and road surfaces made of concrete. the bicycle lanes are visually highlighted with color.

lighting concept
all handrails are equipped with continuous integrated handrail lighting, mainly illuminating pedestrian and bicycle paths without glare, and accentuating the elevation changes between the two areas as a continuous glowing band. additionally, roadway areas are lit only as necessary by a few unobtrusive pendant lamps, partly integrated into the horizontal crossing profiles above the roadway. a few spotlights integrated into the compression arches cast side-light on the net-like distributed tension rods. to counteract increasing global light pollution, colored light effects or excessive staging of the main arch are deliberately avoided.

new construction and demolition
widening the main structure at the supports allows the construction of four new support points without first dismantling the existing bridge and its supports. in the first construction step, only the laterally cantilevered pedestrian elements of the existing bridge are removed, then the two new compression arches can be erected. the existing bridge serves as a working platform. the new load-bearing main structure can then be used in the next construction phase for the sectional demolition of the old bridge.

traffic space design
the prescribed alignment of the double-track tram in mixed traffic operation, with a left-turn lane, is adopted. the one-way bicycle lanes widen toward the supports, creating a generous space at intersections for smooth encounters between pedestrians and cyclists. the required connection to the promenade is achieved by adapting the existing ramp for accessibility, including a branch to the future paddle boat house.