14,000 Readings per Day
The system operates continuously, with Trimble 4D Control managing the measurement and data according to the monitoring require-
ments.  At the end of each 24-hour period, the software merges the 14,000 readings to provide a daily average and loads the data into 
a spreadsheet for comparison against baseline readings. Bridle then analyzes the data and prepares it in the client’s required format. 

“With this system,” explains Bridle, “the Trimble 4D Web module allows us to provide access to selected ‘guests’—including our 
geotechnical advisors—so they can view the data in graph form, as well as zoom in on data snapshots to analyze spikes or other 
unusual readings. This is particularly useful for our own in-house validation system.”

The data goes to the geotechnical staff, where it is checked and then sent back so it can be prepared for the client. “We know 
that the information we are producing—whether graphs showing movement with different values, or charts of our monitoring 
locations—is in a format that is clear, informative and exactly what the client requires.” 

Converging Factors
Several elements made it possible for McAlpine to take monitoring in-house, including technological developments and eco-
nomic factors. “As industry attitudes change, and monitoring becomes mandatory, companies must find cost-effective monitoring 
schemes,” says Bridle. “Technology has helped us achieve cost efficiency in many ways on this project.”

“Our approach is to monitor hourly so we can understand how climatic patterns and different conditions affect our readings,” says 
Bridle. “The Trimble system allows us to do this with no additional labor or maintenance costs—it’s self-sufficient and reliable in 
any kind of weather.”

Assurance…and Reassurance
McAlpine’s dedication to honesty and transparency is evident across the project. Instrument calibration can be checked from 
readings on a database for quality assurance. No recorded data can be deleted, and all findings are clearly stated in the reporting 
system. This data provides assurance for McAlpine’s team of structural and design engineers that they have done their job correctly, 
while reassuring all external parties that the job is being handled properly and professionally. 

“This is a built-up area, and it’s vital that we have the confidence and trust of those around us so that the project will run smoothly,” 
says Bridle. “If an incident does occur, however minor, we are in a position to investigate it within 24 hours, rather than within a 
week as was previously done.” 

The experience gained on this project will provide an excellent blueprint for other monitoring schemes within McAlpine; the team 
is already looking at new possibilities, including the use of Trimble VISION and the total stations’ integrated cameras.  

 “It is clear that monitoring is one of surveying’s fastest growing disciplines, not just for the accepted reasons of safety, planning and 
compliance, but also for the ‘softer’ benefits of trust, confidence and openness,” said Bridle. “These factors can’t be measured, but 
they remain key to a smooth-running project and good community relationships.”

See feature in American Surveyor's Issue 10, #1: www.amerisurv.com