Strainstall in Bridge Engineering and Monitoring

Bridge Monitoring

Strainstall in Bridge Engineering - taking the load

Strainstall has worked on several hundred bridge structures during the last few years. Using state-of-the-art instrumentation and monitoring techniques, our systems provide critical data about structures. We have developed test and monitoring regimes for problem structures, and work closely with consultants, bridge owners and contractors, particularly in repair and strengthening operations. Information delivered includes comprehensive static or dynamic load test data, in-situ live and dead load stresses, and structural health.

Monitoring Systems
Standard or bespoke monitoring systems are designed, installed and maintained for measuring key parameters such as strain, displacement, force, temperature, inclination, alignment and settlement. These can be installed permanently for on-going structural and safety monitoring, or temporarily to ensure safe working during operations such as repair, strengthening and upgrading. Our systems range from simple battery powered static logging systems to fully automated structural health systems, which can be operated indefinitely. This long-term monitoring ensures that any significant change in the condition or behaviour of the structure will be logged and reported where appropriate, reducing the need for regular and costly physical inspection. Data can be made available worldwide via password-controlled web pages hosted by the client or by Strainstall.

Bridgewatch®
Bridgewatch® is a system developed to monitor the behaviour of highway bridge structures. Depending on the structural feature to be observed, a combination of special sensors are installed in the structure which are able to measure the following features:

Change in strain level of reinforcement or concrete
Change in crack size
Variation in stress levels in steel girders
Displacement in composite structures
Relative movements or deflections

An on-site datalogger records the raw data from the installed sensors. This data is automatically downloaded via remote telephone access to Strainstall’s server, where it is processed and posted to the Bridgewatch® website. Any variation in the measured state of the structure is then immediately available to the managing agent.

www.strainstallonline.com

In-Situ Stress Determination
In-Situ stress measurement is based upon instrumented stress relief techniques. These include instrumented coring for concrete, instrumented drilling for steel beams, reinforcement bars and post tensioning tendons, and pressure compensation slot cutting for concrete and masonry.

Load Testing
We routinely carry out short-term response load testing of static or live loads. Measurements can be taken under existing load conditions, such as normal road and rail traffic, or special weighted test vehicles can be used. We have a large stock of various transducers and monitoring equipment that has been specifically designed for bridge testing. Strainstall assist in the planning and execution of load tests and have full capability for static and dynamic testing with up to 256 data channels. Alternative instrumentation is available for faster sampling over fewer data channels. Our experienced engineers understand structural behaviour and ensure that the data provided is accurate and relevant.

Structural Health Monitoring
Our structural health monitoring systems are designed into bridges to monitor key environmental and traffic conditions. Measurement for long span suspension bridges might include deck profile, cable load, hanger vibration, deck vibration, joint displacement and strain. As with any long term monitoring system, usually the data produced confirms that everything is behaving correctly. For this reason, Strainstall’s structural health monitoring systems incorporate sophisticated software that processes data as it is collected, and consequently summarised data is always available. Large volumes of data are only stored under alarm conditions.

Installation
In order to monitor bridges and tunnels successfully it is often necessary to install sensors and other equipment in hazardous or inaccessible places while rail or road traffic remains uninterrupted. Our field engineers are fully trained and equipped for such conditions, including track safety (PTS) rope access and confined space techniques.

Strainstall UK Limited · 9-10 Mariners Way · Cowes · Isle of Wight · P031 8PD · UK
Tel: +44 (0)1983 203600 · Fax: +44 (0)1983 291335 · E-mail: enquiries@strainstall.com

© 2005 Strainstall UK Limited, All Rights Reserved

A James Fisher Group Company
Registered in England at Fisher House, PO Box 4, Barrow-in-Furness, Cumbria LA14 1HR
Registered Number: 4042929 - VAT Number: GB760192441