Insights

How granite bridges the divide between past and future.

INSIGHT: Maria-Ward Bridge

InsightsSTORY
view from a bridge on a lake with a old castle to the left

How granite bridges the divide between past and future.

School path. River. Castle. For centuries, the island in the river Inn was reached by the path over the water. In 2013, the flood tore down this link. What followed was more than just the installation of a replacement: a structure was created that preserves the character of the location, yet is also fit for the future. The project was made possible by a grant provided by the German federal government and the Free State of Bavaria [1]. Natural stone was not part of the original specification. But once the requirements were clear, its selection was almost inevitable. The choice was Tittling fine-grain granite from the nearby Höhenberg Quarry. Granite is also deeply anchored in Neuhaus am Inn - both geologically and culturally. A suitable connection.

 A light-coloured, uniform material, Tittling fine grain granite blends seamlessly into the complex. It is resistant, even without surface coating.

Between heritage and future

Load test of a granite bridge using heavy bulk bags (big bags)A fire truck crossing the granite bridge in front of the castleBridge before reconstruction at Neuhaus am Inn Castle

The requirements could hardly have been more contradictory. On the one hand, protection of a listed building complex; on the other, regular flooding and the need for full functionality for emergency services - including a safe load bearing capacity of up to 20 tonnes for carrying emergency vehicles. 

Wagmann Ingenieure [2] overcame this balancing act with technical rigour and design finesse. The entire project was closely monitored by the historic monuments protection authority. It was essential for the elastomer bearings to remain in place on the listed piers, which is why the piers were renovated by stonemasons. The new structure was designed to remain in place even in the event of flooding.

Three spans - one line

Bridge railing with a modern building in the backgroundNatural stone bridge piers

The bridge consists of three single-span girders, arranged in a row, one after the other. In this way, the post-tensioned granite spans the entire distance with a smooth geometry. The superstructure is just 30 cm thick. This slender profile reduces the blockage in floods and is visually pleasing. The pre-assembled elements were installed in just a few days. A temporary bridge was provided so that the school could stay open. The planning, implementation, and coordination - particularly by the client, Maria-Ward-Schulstiftung Passau [3] – went as smoothly as any municipality could hope. Two cranes, three girders, one week.

A functional design

Close-up of the railing installation on a granite bridge

The floral pattern of the railings echoes the surroundings. The design was a cooperation with Architekt Walter Schwetz[4]. The result was a gentle dialogue between old and new. From a technical point of view, a custom solution was implemented: with the railings attached on the sides and secured to the surface. If there is a risk of floods, they can quickly be removed. Ease of removal was a key criterion for approval and is a good illustration of how design elements can be functionally thought-through.

We wanted a bridge that would blend into the existing infrastructure and provide a link to the new school complex.

Hans Jörg Wagmann, Dipl.-Ing., Managing Director
Old bridge pier of the granite bridge at Neuhaus am Inn Castle
Restored natural stone bridge pier

Disturbance of the historical essence of the site has been kept to a minimum.

The new bridge is part of something bigger:
that lessons continue, even when the water level is rising.
that the infrastructure can blend in.
that a community is willing to invest in the future.

Suitable for daily use

Granite bridge spanning a moat with natural vegetation along the banksCycle path bridge in a rural setting with a streetlight nearbyNatural stream with granite bridge

Around 700 people cross the bridge daily. A school path that is always open and a civil engineering structure that has become system: three further bridges based on the same principle have already been built as part of the land restoration and redevelopment of the Inn riverbanks, which demonstrates the advantages of the granite system.

1     Grant: Bundesrepublik Deutschland und Freistaat Bayern – Programm zur Wiederherstellung der vom Hochwasser 2013 geschädigten Infrastruktur in den Gemeinden

2     Planning and structural engineering: Wagmann Ingenieure GmbH 

3     Client: Maria-Ward-Schulstiftung Passau

4     Design (Railing): Architekt Walter Schwetz, Passau

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