20120725_brücke_ver3_preview

Switzerland

Gleisbogen Bridge

Overview

Problem statement

Intensive construction activity is planned to take place around the Gleisbogen Bridge in Zurich in the coming decade, including several high rise buildings. This will lead to uncontrollable incremental settlements in the whole area, including in the immediate vicinity of this newly built structure.

The question arose if such settlements could lead to uneven load distribution among the hangers of the bridge. This would affect the durability of the structure, as steel arch bridges are sensitive to uneven loading.

Description of the structure

This elegant foot and cycle bridge was erected to connect pedestrian zones either side of a busy traffic artery, and consists primarily of an arch-supported deck with 42m span and with access ramps and stairs at each end.

Monitoring approach

A ROBO-CONTROL “Portable” system was used to determine the forces in all hangers. Based on the measurement results, immediate recommendations for fine-tuning of the new structure could be given on site. The main goal is to avoid any restraints and unforeseen loads.

The project process was defined by the design engineer as follows:

  • Measurement of initial forces in
    hangers

  • Discussion of results on site

  • Corrections, by

    • either increasing or decreasing the tension in each individual hanger or

    • adjusting the height of the bridge using the bridge’s RESTON-POT lifting bearings

  • Control measurements after fine-tuning to check the effectiveness of the
    corrections

Outcome and benefit for the customer

It could be confirmed that the force flow through the as-built structure, following tine-tuning of cable tensions on site, is as intended, with even distribution of loads among the structure’s hanger cables.

Furthermore, the data recorded will serve as a reference for future analysis and adjustments.

More information

Key data

Products:

ROBO®CONTROL “Portable” and RESTON-POT

City:

Zurich

Bridge:

Footbridge