r - The Hong Kong Polytechnic University

efers to data processing and storage includes the tasks of systematic cleansing, reconciling, deriving, matching,
standardizing, transforming, conforming, storing and exporting data and information received from DPCS,
PDAS and PIMS for display, processing, analysis and interrogation. The third function refers to the data
interfacing capability for semi-automatic operation of data retrieval from SHDMS-Server, downloading the
retrieved data into relevant consoles and workstations, and execution of data analysis by the customized
software tools as mentioned in Paragraph 3.3.2. This function is operated through a customized user-interfacing
software tool which links the SHDMS-Server, consoles and workstations together for data communication. The
last function refers to the application of OLAP tools for getting more information such as development trends
from the processed and analyzed data through multi-dimensional views.
5.4 Data Manipulation Requirements
As data processing, analysis and reporting are the key activities of the SHMS and in order to keep such activities
in high efficiency basing on available hardware and software system, a time performance requirement is
therefore set to execute three activities. This time performance requirement is that the time duration for retrieval,
processing, analysis and reporting of any 120 data channels in 86.4 MB data (which is equivalent to the 2-hour
of data collected from 40 nos. of sensors – each at a sampling rate of 100 Hz) should be no more than 6 minutes.
The word “retrieval” means the download of the data from the rolling storage buffer in the SHDMS-server to
the DPCS-workstations. The words “processing, analysis and reporting” refers to the execution of the
customized software tools in the software system for bridge structural system, as mentioned in Paragraph 3.3.2,
in the DPCS-workstations.
6. CONCLUSIONS
6.1 Summary of SHMS Design Process
In the design of a SHMS, the types of measurands required should first be identified and the corresponding
sensory layout should be devised to achieve the six functions as stated in Paragraph 3.2.1. The sensor type is
then selected in accordance with the 12 criteria as stated in Paragraph 3.2.1. Upon completion of sensory system
deployment and selection, the layouts and/or locations of the data acquisition systems and associated cabling
networks should be deployed. Selection of the data acquisition equipments and associated cabling network
systems for data acquisition and transmission should comply with the technical specification of the selected
sensory system. After this stage, the system design work would primarily be on the software systems rather than
the hardware systems. The software system design includes the design of: (i) the software system for control and
display of the instrumentation system, (ii) the software system for monitor and display of the bridge, (iii) the
software system for data interfacing and analysis execution, and (iv) the software system for data operation and
data management. The first software system is essential in keeping the instrumentation system in good operating
condition because though control and display, the operator can quickly identify the malfunction equipment and
promptly arrange for rectification. The second software system is the solely system providing tools to convert
the measured data into codified information so that bridge engineers can make use of this information for
planning and scheduling of their works in design, construction, maintenance and rehabilitation. The third
software system is devised to interface the measured data with the bridge monitoring and display tools and to
execute the requested analysis in the DPCS-Workstations. The fourth software system is devised for the works
of data operation, data storage and data retrieval. The third and the fourth software system are in fact the basis
for semi-automatic processing and analysis of the measured data. The first and second software systems are
installed in the DPCS, whereas the third and fourth systems are installed in the SHDMS.
6.2 Performance Criteria for Monitoring
The monitoring criteria for bridge performance and its environment should be based on design criteria in bridge
codes (such as BS5400 or appropriate Eurocodes) at the serviceability limit state. This approach makes the
monitoring results be acceptable by bridge engineers because its design and operation are complied with the
codified requirements for bridge design, construction, maintenance and rehabilitation, which also forms the
legal basis for monitoring. Under such an approach, all software tools for data processing and analysis should
therefore be customized to transform the measured data into the parameters specified in the bridge design codes.
6.3 Nature and Functions of SHMS
SHMS is in fact a civil-mechatronic system which integrates the knowledge and experience in the fields of
sensing and instrumentation, modeling and simulation, data interrogation and management, and bridgeworks of
design, construction, maintenance and rehabilitation. It should be devised to carry out the functions of collection,
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