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The speakers, Dr Talhan Biro and Dr Reza Ghadim, from GeoSIG Ltd a Swiss manufacturer of seismic and dynamic monitoring systems, and Dr Shelley Zhao, from Building Diagnostic Consultants Ltd a company specialising in building inspection and monitoring, were invited by the BD Division and the Hong Kong Computer Institute (HKCI) to share their technology and experience in the captioned webinar on 25 February 2022.
To begin with, the motivation for implementing Structural Health Monitoring (SHM) was to help optimise management and improve quality assurance. The monitoring includes, but is not limited to, increased understanding of structural behaviour for better design and rational maintenance strategies, early detection and alarms, less downtime, the assurance of serviceability, protection of vibration sensitive facilities, better allocation of resources, and reduced property insurance premiums (if applicable).
3D models of a building structure and a bridge structure with sensor deployment were presented to show how vibration SHM works. Performance parameters like Translations (side-to-side movements of a floor), Torsion (rotation/twisting of a floor), Inter-storey drift (storeys misaligned), and Overturning can all be obtained through monitoring and modelling. Typical instrumentation for buildings includes accelerometers, displacement sensors, strain gauges, and tilt sensors all connected to a central data acquisition unit, with wireless or wired remote data transfer and alarm notification functions.
Finally, real vibration SHM projects from all over the world and Hong Kong were presented as case studies. Many tall buildings, bridges and tunnels have been equipped with real-time vibration monitoring systems capable of continuous 24/7 monitoring for years. The system can also be integrated into existing Building Management Systems (BMS) for better property health and structural serviceability assessments. With SHM, preventive action can be taken early on and thus reduce maintenance costs.
The webinar attracted over 430 participants. The BD Division was grateful for the speakers’ presentation and the excellent support from members of the HKIE and HKCI.
The webinar was organised by the BD Division on 30 March 2022. Ir David Yip, Deputy Engineering Manager of Sanfield Building Contractors Limited, explained the characteristics and difficulties of adopting the innovative ‘Rotational Bridge Launching Method’ (RBLM) during the construction of the captioned project.
First, Ir Yip presented the site constraints and explained the reasons for adopting the RBLM instead of a traditional construction method. To construct and lower the vehicular and passenger bridges between The YOHO Hub and Yuen Long West Station, a rotary platform and turntable with a push-and-pull jack played an important part in rotating the bridges from the south site to the west site. A similar rotary platform was successfully used in mainland China and was erected using nut-and-bolt connections to reduce the potential risk of welding and distortion.
Ir Yip explained how a lifting frame was used to support, rotate and allow seamless lowering of the two bridges. These construction sequences were demonstrated in a video to provide a better understanding. In order to have a smooth rotation of the platform and lower the bridges accurately into permanent positions, regular inspections with torque tests were conducted together with the use of advanced innovative software and a monitoring programme.
Finally Ir Yip summarised the advantages of adopting RBLM to complete a rapid and safe erection in this extremely congested construction site. By using RBLM, the on-track construction time was reduced by 60% thus alleviating potential disruption to daily operations of the Light Rail, West Rail and public transport adjacent to the site. This was the first time this construction method was used in Hong Kong and received a lot of positive news reporting.
On behalf of the BD Division, we would like to express our sincere gratitude to Ir Yip for this fruitful and enlightening webinar.