Summary of Activities

Third-generation structures shall be equipped with an integrated monitoring system that will be able to detect structural deterioration and damage, provide early warning of structural failure, check the reliability of sensing and control systems, and activate the control system to protect the structure from extreme loadings of natural and man-made hazards. Such a system acts as the brain of the structure and involves smart sensors, GPS, GIS, wireless communication and/or the Internet technologies. The monitoring system should provide not only the state of the health of the structure but also information for the control system to make decisions with regard to its activation under extreme loadings. The GIS, especially Internet-GIS technology, provides a useful platform on which an efficient computerized spatial database management system for capture, retrieval, analysis and display of GIS data can be built. Technological Services provided include the following:

• Ambient and forced vibration testing of buildings and bridges
• Design of structural health monitoring systems
• Moving force identification and condition evaluation of bridges
• Finite element modelling and dynamic analysis of cable-supported bridges
• Model updating and validation based on field vibration measurement
• Developement of GIS-based health monitoring and management systems
• Monitoring techniques - GPS, InSAR, and other sensors, and their integration
• Monitoring of the deformations and dynamic behaviors of  buildings and engineering structures, landslides, land settlement, and crust movements
• Sea level changes and associated environmental problems
• GIS and virtual reality technologies for structural health monitoring and damage de-tection
• Integration of GIS and imaging technologies for hazard evaluation, and GIS for hazard rescue control and management.

GIS Laboratory

 

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Representative Projects

• Vibration monitoring of Lautau Fixed Crossing
• Lantau Fixed Crossing and Ting Kau Bridge wind and structural health monitoring masterplan task 7.12
• Field tests under agreement No. CE76/97: Investigation for rehabilitation of Tsing Yi South Bridge
• Structural damage detection of cable-supported bridges by vibration measurement
• Experimental study on seismic damage detection of tall building structures
• Innovative optical fibre sensors for structural health monitoring of Tsing Ma Bridge
• High precision automatic measurement of natural and cut slope deformations to pre-vent disasters;
• Landslide modeling using data of slope deformation monitoring;
• Atmospheric effects in interferometric synthetic aperture radar (InSAR) measurements in Hong Kong and Southern China
• Collaborative research Center (CRC) for Ground Engineering and Technology; 
• GPS and GIS for Urban Hazards Mitigation;
• The use of GPS measurement for real time monitoring of structural vibrations;
• Robust matching for automated detection of surface deformations;
• Enhanced InSAR technology for monitoring of earth surface deformation;
• Development of structural health monitoring and management system based on geo-graphic information system technology;
• Integration of GIS, CAD and virtual reality for construction.

Sensor Map of Ting Kau Bridge

Gain Information of the selected sensors

Data Display

Vibrations of Di-Wang Tower measured with GPS (Top plot: NS direction, bottom plot: EW direction, unit: mm)

Slope deformation measured with inclinometers

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Major Facilities

• B&K vibration testing package (BK4802&4817 exciters; BK1049 sine/noise signal generator; BK2708 power amplifier; BK3550 16-channel spectrum analyzer including data acquisition unit BK2816 and signal analyzer unit BK2035)
• 32 Channel INV303E Data Acquisition and Signal Processing System (with INV-DASP632 software)
• Computer system with DAT Tape Drive and SPiDAR software specific for on-line health monitoring and compatible with WASHMS
• A set of field measurement instrument including exciters, accelerometers, displacement transducers, anemometers, tape recorders, etc
• 3m x 3m shaking table (Type: MTS; Degree of freedom: one direction; Frequency range: 1 to 50 Hz; Displacement limit: 100 mm; Acceleration limit: 1 g; Load limit: 10 ton)
• dSPACE DS1005 real-time control system (DS1005DSP board; DS2003 32ch A/D; DS2102 6ch parallel D/A; PX10N expansion box; CDP1005 total development package)
• Both Unix workstations and PCs, the workstations include 5 sets Sun Sparc 20 (Model 50), 1 set Hewlett-Packard, 1 set Digital Unix v4.0 878 Alpha (533au2 dual CPUs, 2 GB RAM, 81 GM HD). These workstations are linked to each other through network
• 1 A0 size Calcomp 9500 digitizer
• 1 A1 size HP7580 plotter
• Over 10 geodetic quality GPS receivers
• Various GPS data processing software packages
• 4 Arc/Info 8.0 (including the major extension modules)
• ArcView 3.2
• Autodesk MapGuide
• MapInfo
• GeoMedia and other products from Intergraph.

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Selected Publications

• Lam, H.F., Ko, J.M. and Wong, C.W. (1998), "Localization of damaged structural connections based on experimental modal and sensitivity analysis", Journal of Sound and Vibration, Vol. 210, No. 1, 91-115.
• Law, S.S., Shi, Z.Y. and Zhang, L.M. (1998), "Structural damage detection from incomplete and noisy modal test data", Journal of Engineering Mechanics, ASCE, Vol. 124, No. 11, 1280-1288.
• Chan, T.H.T., Law, S.S. and Yung, T.H. (2000), "Moving force identification using an existing prestressed concrete bridge", Engineering Structures, Vol. 22, No. 10, 1261-1270.
• Ni, Y.Q., Lou, W.J. and Ko, J.M. (2000), "A hybrid pseudo-force/Laplace transform method for non-linear transient response of a suspended cable", Journal of Sound and Vibration, Vol. 238, No. 2, 189-214.
• Xu, Y.L., Zhu, L.D., Wong, K.Y. and Chan, K.W.Y. (2000), "Field measurement results of Tsing Ma suspension Bridge during Typhoon Vector", Structural Engineering and Mechanics, Vol. 10, No. 6, 545-559.
• Chan, T.H.T., Li, Z.X. and Ko, J.M. (2001), "Fatigue analysis and life prediction of bridge with health monitoring data - Part II: application", International Journal of Fatigue, Vol. 23, No. 1, 55-64.
• Law, S.S., Chan, T.H.T., Zhu, X.Q. and Zeng, Q.H. (2001), "Regularization in moving force identification”, Journal of Engineering Mechanic"s, ASCE, Vol. 127, No. 2, 136-148.
• Xu, Y.L. and Zhan, S. (2001) "Field measurements of Di Wang Tower during Typhoon York", Journal of Wind Engineering and Industrial Aerodynamics, Vol. 89, No. 1, 73-93.
• Ko, J.M., Sun, Z.G. and Ni, Y.Q. (2002), "Multi-stage identification scheme for detecting damage in cable-stayed Kap Shui Mun Bridge", Engineering Structures, Vol. 24, No. 7, 857-868.
• Ko, J.M., Chak, K.K., Wang, J.Y., Ni, Y.Q., and Chan, T.H.T. (2003). "Formulation of an uncertainty model relating modal parameters and environmental factors by using long-term monitoring data", Smart Systems and Nondestructive Evaluation for Civil Infrastructures, S.-C. Liu (ed.), SPIE Vol. 5057.
•  Ni, Y.Q., Li, H., Wang, J.Y., and Ko, J.M. (2002d). “Implementation issues of novelty detection technique for cable-supported bridges instrumented with a long-term monitoring system”, Nondestructive Evaluation and Health Monitoring of Aerospace Materials and Civil Infrastructures, A.L. Gyekenyesi, S.M. Shepard, D.R. Huston, A.E. Aktan and P.J. Shull (eds.), SPIE Vol. 4704, pp. 225-236.
• Ni, Y.Q., Wang, B.S., and Ko, J.M. (2002e). “Constructing input vectors to neural networks for structural damage identification”, Smart Materials and Structures, Vol. 11, No. 6, pp. 825-833.
• Ni, Y.Q., Fan, K.Q., Zheng, G., Chan, T.H.T., and Ko, J.M. (2003). “Automatic modal identification of cable-supported bridges instrumented with a long-term monitoring system”, Smart Systems and Nondestructive Evaluation for Civil Infrastructures, S.-C. Liu (ed.), SPIE Vol. 5057.
• Wang, J.Y., Ni, Y.Q., Ko, J.M., and Chan, T.H.T. (2002). “Damage detection of long-span cable-supported bridges”, Structural Health Monitoring: Proceedings of the 1st International Workshop on Structural Health Monitoring of Innovative Civil Engineering Structures, A.A. Mufti (ed.), ISIS Canada Corporation, Winnipeg, Canada, pp. 299-308.
• Chen, Y.Q., Ding, X.L., Huang, D.F. and Zhu, J.J. (2000) A Multi-Antenna GPS System for Local Area Deformation Monitoring, Earth, Planets and Space. Vol. 52, No. 10, pp. 873-876.
• Liu, G.X., Ding, X.L., Chen, Y.Q., Li, Z.L. and Li, Z.W. (2001) Monitoring land subsidence at the Chek Lap Kok Airport Using InSAR Technology, Chinese Science Bulletin. Vol. 46, No. 21, pp. 1778-1782. (English Ed.)
• Liu, G.X, Ding, X.L., Chen, Y.Q. Li, Z.L., Li, Z.W. (2003) The Pre- and Co-Seismic Ground Displacements of the 1999 Chi-Chi Earthquake from ERS-SAR Interferometry, Chinese Journal of Geophysics, Vol. 45, pp. 165-174.
• Ding, X.L., Liu, G.X., Li, Z.W., Li, Z.L., Chen, Y.Q. (2003) Ground Settlement Monitoring in Hong Kong with Satellite SAR Interferometry. Photogrammetric Engineering and Remote Sensing, (in press).
• Li, ZL, Xu Z, Cen MY, and Ding XL (2001). Robust surface matching for automated detection of local deformation using least median of squares estimator, Photogrammetric Engineering and Remote Sensing, 67(11): 1283-1292.
• Shi, W.Z., Yang BS and Li, QQ (2003) An Object-Oriented data model for complex objects in three-dimensional Geographic Information Systems. International Journal of Geographical Information Science. Vol. 17, No.5, Pp. 411-430.
• Zhu, CQ., Shi, WZ, and Wan G, (2002) Reducing remote sensing image and simplifying DEM data by multi-band wavelet. International Journal of Remote Sensing, Vol. 23, No.3. pp 525-536.
• Shi, WZ, Ko, JM, Pang, YC , Siu, SH, and Kan, SH (2001). GIS for bridge health monitoring in Hong Kong, Proceeding of SPIE, Health monitoring and management of civil infrastructure systems, Newport Beach, USA, 6-8 March 2001, Vol. 4337, pp. 314-322.
• Cheng, P.G, W.Z. Shi, J.M. Ko, 2003, GIS-Based Bridge Structural Health Monitoring and Management System, East China Highway, 2003, Vol. 6.
• Shi, W.Z., P.G. Cheng, J.M. Ko, C. Liu, 2002, Development of GIS-Based Bridge Structural Health Monitoring and Management System, Proceedings of  SPIE. Smart Structure and Materials 2002 and Nondestructive Evaluation for Health Monitoring and Diagnostics, San Dingo, California, U.S.A, March 2002. Vol. 4704, pp.12-19.

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Contact Information

Contact Person

Prof. J.M. Ko Department of Civil & Structural Engineering The Hong Kong Polytechnic University Kowloon, Hong Kong Fax:     + 852 - 2362 2574 Phone:   + 852 - 2766 5036 E-mail:  cejmko@polyu.edu.hk

Prof. Y.Q. Chen Department of Land Surveying & Geo-Informatics The Hong Kong Polytechnic University Kowloon, Hong Kong Fax:     + 852 - 2330 2994 Phone:   + 852 - 2766 5966 E-mail:  lsyqchen@polyu.edu.hk

Other Investigators

Prof. Y.L. Xu (ceylxu@polyu.edu.hk)
Prof. H.L.W. Chan (apahlcha@polyu.edu.hk)
Prof. C. Gold (lscgold@polyu.edu.hk)
Prof. Z.L. Li (lszlli@polyu.edu.hk)
Dr. T.H.T. Chan (cetommy@polyu.edu.hk)
Dr. X.L. Ding (lsxlding@polyu.edu.hk)
Dr. S.S. Law (cesslaw@polyu.edu.hk)
Dr. Y.Q. Ni (ceyqni@polyu.edu.hk)
Dr. W.Z. Shi (lswzshi@polyu.edu.hk)
Dr. LH Yam (mmlhyam@polyu.edu.hk)