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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

Non-destructive testing of Marine Jetties

Price & Wardle used the electro-level AMS in the 80s to issue loading Certificates for several marine jetties. Tugboats as shown in the picture above applied three or four levels of relatively low loads to the jetty. Bending strains, rotations and deflection of elements of the structure as a result of the applied loads were calculated from electro-levels fitted to the structure. With the known or tested material strengths of the elements, the safe loading for the jetty could be determined and Certificates issued. In addition to the physical loading tests Finite Element models of the marine structure were made and theoretical loading performances calculated. These were compared to the physical results to add to the general understanding of the performance of the jetty.

The system proved to be relatively inexpensive and versatile, and if properly deployed allowed the calculation of bending strains and degree of fixity of the total structure to be determined.

During the tests the relatively small array of instruments (16 electro-levels), could be easily moved to check or supplement information from any of the elements such as bending strain in the piles, or their fixity to the deck or at the seabed.

The sketch shows the component parts of a typical wood or concrete marine jetty. The importance of being able to carry out non-destructive testing on such structures is that very often the original calculations and assumptions are difficult to trace or have been lost over the years.

Also without adequate records of the loading history of a structure, loss of material due to corrosion and scouring of the founding soil around the piles, it would be impossible to assess its current load capacity with any accuracy.

In France a £4 million new jetty had been moved sideways by a landslide and had to be removed and rebuilt, or tested to prove it was safe. The jetty was supported by both vertical and raked piles, a selected number of which were diamond cored to a depth of 15 m (the mud line was at 4 m). A series of electro-levels were installed in the drilled holes to monitor the lateral movement of the piles below the surface. A dead weight load 1.5 times the design load was applied to the deck. The results from the electro-levels allowed deflection and bending strains of the supporting piles to be determined during the loading. The tests proved the jetty carried the vertical load with no excess lateral movement and could therefore be brought into service saving not only the £4 million, but also the cost of removing and rebuilding a new jetty.

	The photgraphs (above and left) show the testing of Greenheart timber piles. The photo (above left) shows load fender piles by a small work boat. The photo (above) shows a Greenheart pile being tested to failure in the Laboratory and the photo (left) a diver attaching an electro-level at the seabed to monitor the degree of fixity of the pile. The photgraph (below left) shows an electro-level fitted to a concrete pile by a clamping bracket to monitor deflection and bending strains. The diagram below shows a simple Finite Element model of a jetty used to back analyse performance.