Monitoring business

IWP&DC: Please give a background to Huggenberger

Vincenzo Caci: Founded in Switzerland in 1900, Huggenberger started out manufacturing precision callipers. Among one of the first companies to see the importance of having measured data from dams, it then decided to turn towards manufacturing monitoring instruments. 

Throughout the years, the company has experienced several changes in ownership and management, but the focus has always been to produce top quality and long-term reliable instruments for dams. Since 2003 it has been owned and ran by Mr Marti and Ms Meier. In January 2018, Huggenberger was acquired by SISGEO of Italy, one of the leading companies in the geotechnical instrumentation manufacturing market. However, SISGEO has decided to maintain Huggenberger’s headquarter and production facilities in Switzerland. 

Although the synergies between different companies are sometimes not easy to achieve, I’m convinced that being part of SISGEO group is a guarantee for the long-term development of Huggenberger. We now have access to higher resources to be spent in R&D to fit the future market’s need. At the beginning of next year, we’ll start the development of the new series of our Telelot Telependulum which will be based on the most advanced technologies. Finally, I guess it is good news for the whole market to count on a group with such large and varied experience of more than 600 dams instrumented worldwide.

Could you give a summary of the work that you carry out in relation to geotechnical monitoring? 

In general, Huggenberger manufactures instruments which are utilised in the monitoring systems of civil structures, infrastructure, tunnels, dams and various geotechnical projects. Our core business is dam monitoring, with particular focus on concrete dams. Automation of existing dams is also one of our main areas due to our expertise in old measurements systems. Load measurement on anchors is another sector where we are well recognised, mostly in the domestic market. In order to diversify our business, more recently we have entered into different markets, providing our instruments for rockfall monitoring and for several tunnel applications. 

Rockmeter installed in tunnel line for displacement measurements

What equipment do you use?

For concrete dams, the main equipment is the pendulum line, which can be read either manually by our Coordiscope or automatically by our Telelot Telependulum. Both devices have been developed and engineered to work in harsh environments such as dam galleries. The current versions came from years and years of experience. The features of such devices allow perfect working and high precision on a long-term basis. Our range of products includes other measuring instruments such as displacement transducers, thermometers, strain gauges, piezometers and of course the automatic data acquisition units. Special care has to be given to cables, since the cabling is generally one of the weak points for a dam monitoring system and can easily be damaged.

With regard to the geotechnical applications, such as deep excavation or landslides, load cells are certainly the most required and appreciated instruments. We produce and calibrate the complete instrument in our laboratories in Switzerland.

Load cells ready for dispatch

What dam projects have you have worked on?

Before introducing our latest project, I cannot forget that our first instrumented dam dates back to 1923 and it’s Schräh Dam in Switzerland. At 111.6m it was the world’s highest hydro dam at that time.

Recently, we have been working on existing dams and the main activity has been the supply of Telelot automatic pendulum systems. This system is able to measure with high accuracy and repeatability the small movement of the dam body and is mainly installed into concrete dams. Data coming from automatic pendulum lines are very important for dam stakeholders to understand the behaviour of the whole structure. Of course, we also offer our supervision and expertise during the installations. 

Some of the latest projects we have worked on include:

?    Katse dam, Lesotho

?    Emosson dam, Switzerland

?    Muttsee dam, Switzerland

?    Seymareh Dam, Iran

?    Bavigne dam, Luxembourg

?    Karun 4 dam, Iran

?    Isola dam, Switzerland

?    Krokstromeen, Sweden

Have monitoring methods changed and has equipment become more sophisticated over recent years?

In general, the monitoring instruments market is not very fast in moving toward new technologies. This is especially true in dam monitoring. Dam design, construction and exploitation are quite long processes, for this reason proven and reliable instruments are generally preferred for monitoring purposes. For example, one of the most important technologies is still represented by vibrating wire sensors, which are utilised mostly in non-retrievable instruments thanks to the proven long-term reliability and simplicity. We have observed in recent years there are greater requests for automation of dam monitoring systems, thanks to the new available datalogging technologies and communication interfaces, which allow large amount of remote data transmission.

In addition, software for data management and processing are becoming more important, because they can elaborate monitoring data, generate reports and finally provide a comprehensive batch of information in nearly real-time.

High-precision portable clinometer

Why is geotechnical monitoring so important for the safety and security of civil engineering structures such as dams?

Well, Lord Kelvin used to say “When you can measure what you are speaking about and express it in numbers, you know something about it…”

Geotechnical monitoring is the point where the theory and the observation can match. Thanks to instrumentation, one can measure a parameter and compare it with observed phenomena and with the assumption made at design stage. As a result, monitoring gives deeper knowledge of the structures and it allows improving quality of new structures.

It should also be underlined that geotechnical monitoring has the task to control the behaviour of the structures throughout their operational life and this is extremely important for the dams.

Telelot installed in Emosson Dam

How does the geographical location affect geotechnical parameters of projects? 

For sure the geographical location affects geotechnical parameters. Each location has its particular geological, geotechnical, geo-physical and geo-mechanical features. All those aspects are taken into account during the design and the most important parameters are then selected by the designer. The next step is to then select the most suitable instrumentation to monitor these parameters.

There are also other aspects related to the geographical location that influence the monitoring system. For example, a dam located in a hot and humid region, eventually surrounded by aggressive waters, is very challenging for the instrumentation. Altitude is another parameter which can highly influence the performance of monitoring instruments. 

In general, we can say that locations with hard condition in terms of temperatures variation,
altitude, humidity etc are recognised as the more demanding ones. 

Pendulum Line in Carmena Dam

Looking to the future, do you think that geotechnical methods or equipment will need to develop further in any way? 

Climate change will definitely have an impact, actually I’m afraid this is already happening. The sudden variation of hydrogeological regime can strongly affect the hydraulic structures which were designed years ago based on different information. In this sense, the need to provide reliable information about basic parameters of geotechnical structures makes monitoring even more important. The equipment needs to be developed in order to allow monitoring of further parameters and provide more information. I guess the contribution of all dam stakeholders, and not only the manufacturing companies, is needed to improve the performances of the complete market.