Pile Dynamics remote testing technologies for the deep foundation industry help keep projects moving safely during the pandemic.
The COVID-19 pandemic has affected all industries worldwide including the construction industry. Companies are being forced to rethink daily operations and adapt business models to align with new social distancing guidelines. The Occupational Safety and Health Administration (OSHA), a federal agency of the United States responsible for workplace safety, has issued guidance for construction operations to mitigate risk exposure by implementing engineering controls.
The Pile Dynamics technology offers remote sensing techniques for deep foundations. When a project requires a non-destructive testing of drilled shafts, augered cast-in-place (ACIP), and diaphragm walls, the Thermal Integrity Profiling (TIP) system can be used as a tool to further help mitigate COVID-19 and other risks.
TIP supports accelerated construction because shaft acceptance can be accomplished long before other integrity evaluation methods can be deployed for testing. Often, TIP saves the project time and money.
The TIP system utilizes heat generated by curing concrete to assess shaft integrity and reinforcing cage alignment. PDI’s data loggers, Thermal Aggregator (TAG) collect TIP data from multiple Thermal Acquisition Port (TAP-EDGE) boxes attached to a foundation element. Automatically, the TAP-Edge boxes transmit all data to the secure PDI-Cloud portal. This system mitigates the risk exposure by eliminating most onsite contact between the TIP consultant and the project team.
Signature Bridge, Miami, Florida
The largest construction project that utilizes 100% TIP testing is currently ongoing in Miami, Florida. The I-395/SR-836/I-95 Signature Bridge is a complete reconfiguration of a key transportation corridor in downtown Miami and will incorporate thousands of 30 in (760 mm) and 36 in (910 mm) CFA piles ranging in length from 85 ft (26 m) to 135 ft (41 m).
Using the TIP system, all piles are instrumented with Thermal Wire cables and use PDI’s cellular-based TAG/TAPEdge system to push collected data to a secure cloud-based server. After each pile installation, one TAG and three TAPEdges are attached to the Thermal cables on each pile. Then the temperature vs. depth data is collected every 15 minutes and pushed to the cloud-based server every hour. As a result, data are remotely accessed and analyzed. Analysis can be far more efficient because results are available quicker.
“We are using Thermal Integrity Profiling to evaluate the integrity of auger-cast piles for support of the I-395 Signature Bridge project in Miami. PDI has been very responsive and helpful,” Joshua Adams, Universal Engineering Sciences, Inc, mentioned.
Implementing Thermal Monitoring with Integrity Testing
In this large Circle Interchange reconstruction project located in Chicago which will be completed at a cost of $800 million, portions of the current phase were converted from Crosshole Sonic Logging (CSL) to TIP.
The scope of this project phase includes integrity testing of approximately 100 drilled shafts 6 ft (2 m) in diameter and 80 ft (24 m) in length. Each shaft is instrumented along the longitudinal rebar with Thermal Wire cables installed equidistantly around the reinforcing cage. After concrete placement via tremie method, a TAG and TAP-Edges are connected to the cables to begin remote data collection.
Mass concrete is also being monitored in terms of temperature alterations. A single node Thermal Wire cable has been installed approximately 15 ft (4 m) below the top of the concrete close to the shaft center. Throughout the hydration process, the temperature differentials are monitored between center sensor and a sensor located on a perimeter cable at the same elevation.
In addition, peak concrete temperatures near the core are monitored and real time data is transmitted to the project team. Throughout summer 2020, the thermal monitoring data has been used to adjust the thermal control plans to help keep the curing concrete within project specifications. The shafts peak in approximately 30 hours after placement which is when GRL Engineers view the data and issue preliminary results. The most critical time for recording TIP data occurs during the hydration curing process until peak concrete temperature is reached.
Source: Pile Dynamics