SIMCES: System identification to monitor civil engineering structures

• Research unit: EU RFP
• Project number: 96.0202

Key words (English)

System identification; monitoring; civil engineering structures; finite element model updating; damage detection; damage localisation; condition assessment

Alternative project number (English)

EU project number: BRPR-CT96-0277

Research programs (English)

EU-programme: 4. Frame Research Programme - 2.1 Industrial and materials technologies

Short description (English)

See abstract

Further information (English)

Full name of research-institution/enterprise:
Eidg. Materialprüfungs- und Forschungsanstalt EMPA
Abteilung Massivbau

Partners and International Organizations (English)

Katholieke Universiteit Luven, (Co-ordinator) (B), Aalborg Univesitetscenter (DK), Swiss Labs for Materials Testing & Research (CH), Leuven Measurements Systems (B) WS/Atkins (UK), SINECO, M. Garozzo (I), Technische Universität Graz (A)

Abstract (English)

Civil engineering structures (CES) are subject to environmental, service and accidental actions, which may cause damage to the structures. Regular inspection and condition assessment of CES are necessary to determine the safety and reliability. Early damage detection and localisation is vital for effective programming of maintenance and repair work of engineering structures. This allows to minimise the annual costs for maintenance and repair (~1.5% of initial value p. a. for bridges) and may help to avoid long out of service times with possibly even higher economic costs (e.g. traffic delay due to major bridge repair).
The SIMCES project focused on making use of operational vibrations. There was some debate whether measured deviations of dynamic properties of a structure such as eigenfrequencies, modeshapes etc. are sensitive and reliable enough for damage detection and localisation. In addition, it was not proofed, that environmental influences like temperature changes could be separated from effects due to damage.
In the course of the SIMCES Project a long term monitoring system called 'Environmental Monitoring System' (EMS) had been installed on a test bridge in Switzerland. The EMS quantified the degree of variance of the dynamic properties due to environmental influences and delivered a basis for a correlation. To complement the long term test and to provide a feasibility proof, seven different damage patterns were applied in progressive manner to the test bridge in Switzerland. These 'Progressive Damage Tests' (PDT) took place in August 1998 and were complemented by laboratory tests on beams. Within the SIMCES project an optimum dynamic testing procedure was developed in order to obtain high quality experimental data. Recently developed time domain system identification methods were applied to extract the required dynamic properties from the data. Special Finite Element (FE) programs were developed to model the behaviour of damaged (cracked) concrete structures. These FE models were updated based on experimental data. By using general damage patterns and stiffness based calculations, the simulated damages during the PDT's could be detected without making use of a priori knowledge. The envisaged feasibility proof - whether damage detection for real live CES is possible or not - was achieved and a number of praxis ready tools were developed and tested.
The data collected (17 CD-ROMS) may be made accessible by the EMPA to interested researchers.

References in databases (English)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 96.0202