20120725_brücke_ver3_preview

Switzerland

Weyermannshaus Viaduct

Overview

Problem statement

During a detailed visual inspection of the underside of the bridge, considerable cracking was discovered at several coupling joints of the post-tensioned structure. Uncertainty about the time of crack appearance raised concern about structural safety. In order to ensure serviceability for another 35 years of operation, mageba was contracted to install a remote, long term monitoring system. The project was conducted in cooperation with the responsible renovation engineer that was already planning other remedial works such as replacement of bearings, joints and drainage systems. The monitoring data would serve in determining appropriate remedial works for the structure.

Description of the structure

The Weyermannshaus Viaduct is part of the national highway network of Switzerland and a key element of the bypass highway of the Swiss capital Bern. It was built in 1974 - 1977, with a main length of approximately one kilometre. The concrete structure is longitudinally post-tensioned and both highway directions are structurally connected together.

Monitoring approach

A ROBO-CONTROL permanent “ADVANCED” system was needed to fulfil the project requirements. In order to support the calculations of the engineer, changes in crack widths due to known traffic loads and temperature variations had to be monitored. It was decided to proceed in three steps:

1

Calibration measurements:
Single load scenarios with a 40t truck were simulated at different speed levels.

2

Traffic load impact:
Measurements at high frequency (200Hz) were conducted to assess the impact of actual traffic loading during a period of one week in each season of a year.

3

Long term monitoring:
Installation of a permanent monitoring system to assess long-term impacts, with all data presented via a web
interface.

Outcome and benefit for the customer

  • Structural safety and serviceability were confirmed satisfactory under current loading conditions.

  • A fatigue assessment confirmed another 35 years of operation for the main structure.

  • No major rehabilitation works are
    required.

More information

Key data

Products:

ROBO®CONTROL permanent “ADVANCED”

City:

Near Bern

Built:

1974 - 1977

Bridge:

Viaduct