20120725_brücke_ver3_preview

P.R. China

Run Yang Crossing

Overview

Problem statement

After completion of construction and opening to traffic, unexpectedly large movements of the structure were observed, which resulted in excessive wear on bearings and expansion joints. Especially the sliding materials and the elastomeric control springs of the bridge’s expansion joints showed clear signs of accelerated wear.

An inspection and measurement project was initiated, using a “Portable” system to quantify movements and to better understand the structure’s overall behaviour.

Description of structure

The Run Yang Bridge is located about 300km west of Shanghai on the route between China‘s Zhenjiang city in the south and Yangzhou city in the north. The bridge contains both cable stayed and suspension structures.

The cable suspended section with its 1.49km-long main span, a total length of 2.5km, and 210m-high towers, is the fourth longest suspension bridge in the world.

Monitoring approach

The local bridge engineer required measurements of the following characteristics over a period of two weeks:

1

Accumulative movements

2

Absolute movements at bearings and expansion joints

3

Incremental rotations at joints

4

Event counting of load cycles at
expansion joints

5

Environmental data to enable assessment of meteorological impacts

Comparison of the measured movements with the theoretical design movements of the bridge model would allow evaluation of the unforeseen bridge movements. A special focus was placed on the impact on the sliding materials of the bearings and expansion joints.

Outcome and benefit for the customer

The monitoring system was used to conclude that the movements at the suspension bridge greatly exceed expected values. The bridge engineer could use the information provided to plan remedial works to improve the structural performance and to prevent excessive wear of the bearings and expansion joints, for instance by the addition of damping devices, which can be easily installed on a finished structure during operation.

More information

Key data

Products:

ROBO-CONTROL “Portable” and TENSA-MODULAR

City:

Between Zhenjiang and Yangzhou

Bridge:

Suspension bridge