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1. Index
2. CMCS at BRE
3. Development of AMS
4. Non-destructive testing of Marine Jetties
5. Fixed sensor monitoring of Diaphragm walls
6. Monitoring Buildings during Redevelopment
7. Tunnel Monitoring
8. Embankment Systems
9. Loggers
10. Tunnel Distortion Monitoring
11. In-place tilt monitoring system
12. Tunnels Interaction System
13. Re-Development of Small Properties
14. Viaducts
15. DLR at Mansion House
16. Tunnel Monitoring System (Discrete beams)
17. CTRL 240
18. Dams
19. Electro-levels
20. Movement indicators
21. Results of Charing Cross Load Cells
22. Non-destructive testing of concrete structures
23. Radio in Construction Monitoring
24. Settlement Reducing Piles
25. Land Surveying and Total Station Monitoring
26. Vibration Monitoring
27. Monitoring the complete strain history of concrete elements
28. Past CMCS Projects

The benefit of using electro-level systems to assess the engineering performance in dams is in the simplicity of fixing the devices to the material or structure. When inserted in soils they can be used to determine shear modulus and when clamped on to beam elements, they can be used to calculate the deflections, bending moments, shears and loads on those elements.

To develop the techniques needed to successfully use electro-level systems for Construction monitoring required several years of both laboratory and full-scale testing. Much of this work was carried out in the late 70s early 80s by Cooke, Price and Wardle while at the Building Research Establishment (UK).

Electro-levels used to monitor Dams

One of the largest rock filled dams in the world, the 178 m high Tianshenqiao (TSQ-1) dam in China was monitored during its construction, by Professor Pedricto Rocha Filho of Brazil, using 70 CMCS electro-levels.

In developing the system for dams, initial trials were carried out on several structures for Thames Water. London has several brick built embankment-supported reservoirs, the engineering performance of which need to be checked continuously for safety reasons. The electro-level system was used for a number of years to provide 'in-service' performance data on the movements and strains taking place within these well-established structures over looking populated areas, such as the brick built reservoir at Nunhead, SW London. The automatic systems monitored hourly performance and provided safety critical data at a fraction of the cost of conventional manual surveying, without the need to empty the reservoirs. Several large water storage tanks were also monitored using electro-levels to determine imposed bending moments on elements of the retaining structures during filling tests, i.e. at Barrow-in-Furness for North West Water, Cardiff in South Wales for Wallace Evans Consulting Engineers, Glasgow for Thorburns and Dundee for Keller Colcrete. Long-term performance tests were also carried out on earth dams for Yorkshire Water at Walshall Dean.

The system was also very successfully deployed on the Roadford dam in the late 1980s and is still operational today, over twenty years later.

Monitoring carried out using electro-levels on the Xingo dam, in Brazil, by Professor Rocha, showed that using the technique of curve fitting through the results provided valuable data at a fraction of the cost of conventional instrumentation. Horizontal movements of the crest calculated from the electro-levels compared very favourably with movements monitored by conventional surveying results. The most exciting information coming from the electro-levels was their ability to monitor long-term movements along the whole length of the submerged concrete membrane. The use of a limited number of electro-levels with curve fitting procedures and mathematical models offers a more cost effective method of determining the performance of these large structures than has previously been available.