Wireless Sensors in Prestressed Concrete Piles - Combining Driving Controlwith Long Term Monitoring

摘要

This presentation summarizes the design, instrumentation, construction and driving of precast,prestressed concrete piles in the construction of the Key Royale Bridge on Anna Maria Island inFlorida, USA. The durability of the piles was improved with the addition of highly reactivepozzolanic admixtures, including ultrafine fly ash, ground granulated blast furnace slag, andmetakaolin. These pozzolans reduce the permeability of the concrete, thus protecting theprestressing strands by delaying the intrusion of salt water into the concrete. Preventingmicrocracking of the piles during driving is also a key factor in extending the life of the structure.Wireless instrumentation installed during casting was used to monitor the strains and accelerationsduring driving. These techniques of stress and capacity monitoring provide more precise stresswave monitoring than the typical pile driving analysis (PDA). This presentation covers the detailsof the wireless sensor technology installation and data collection. In addition the possibility ofusing the wireless sensor technology for long-time data collection will be discussed.