WP 7
Demonstration.

Field Testing of Bridges

Introduction

A major way to demonstrate the real capacity of a bridge is to load it to failure. Not very many such tests have been performed due to the high costs involved. However, on the occasions where tests to failure have been carried out, a very high load capacity has been obtained. For example, on "Malmbanan", a railway line for iron ore transportation in northern Sweden, a concrete trough bridge reached three times its calculated ultimate limit state load before deformations started to grow nonlinearly and the bridge failed. Similar excess capacities are expected to be found also in other types of bridges.

In order to be able to use such kinds of hidden capacities, demonstrations are needed. They will help explain what the real failure mechanisms are, what kind of load redistributions are possible and how does the theoretical models predict this.

Bridges, transition zones and embankments will be instrumented and loaded to failure to test what actually happens.

Objectives

The objectives for WP 7 are:

• Put in practice some testing systems for selected existing bridges (concrete and steel).
• Inspect overall usefulness and reliability of some testing systems (concrete and steel).
• Assessment of current conditions of bridge.
• Foundations with limited accessibility.
• Provide complementary field-data for physical phenomena of interest to other WPs.