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Tomorrow's Technology Today
Optical Sensing Solutions, IoT
New Jersey/Pennsylvania Turnpike Connector Bridge
About The Bridge
The Delaware River Turnpike Bridge (DRTB) was built in 1956, is jointly owned and maintained by the New Jersey Turnpike Authority (NJTA) and the Pennsylvania Turnpike Commission (PTC) and carries approximately 46,000 vehicles per day. The traffic volume is anticipated to increase significantly now that PTC’s I-95 PA Turnpike Interchange has diverted I-95 traffic over the DRTB.
Monitoring System Objective
WSP a structural design consulting firm charged with investigating the best method for monitoring after repair choosing Fiber Optics comparing many legacy sensors on today's market for long term SHM monitoring projects. WSP built finite element models to determine sensor locations based on fracture simulations. Cleveland Electric Labs and ChM4 initial concepts was awarded the contract. ChM4 with a proven track record in Optical technology projects was tasked with project managing, design of the system and installation with WSP engineers assisting in this effort. ChM4 methods of design was determined to be the most cost effective, long life capable and most accurate on the market today. Instrumentation using optical FBG interrogators with a combination of sensors using Strains with integrated temperature compensation, single axis accelerometers, absolute environmental temperature and tilts oil filled with opposing compensation for a total optical sensor count of 396 FBG sensors. The system only required power for one optical control panel, all sensors are passive (no power needed) and has redundant capabilities. The remote bridge panel streaming to web hosting on our Azure Cloud Service 24/7 website using IntelliOptics® structural health monitoring software developed by ChM4 to monitor the bridge with secured logins to WSP, NJTA and PTC. The optical system spans the entire bridge in critical locations creating a true fracture monitoring system to warn WSP and the Turnpike Authority's should a fracture event happen in the future with specific protocols to protect the public. Two cameras are also used on the PA and NJ portals of the bridge. The system is programmed to focus on alerts in sensor zones 1 thru 8 should they reach the warning protocols established by WSP.
Bridge Failure Description
An apparent construction error six decades ago could have caused the fracture discovered in a steel beam that forced the closure of the Delaware River Bridge, an engineering expert who viewed pictures of the sheared stringer shown below. An image of the sheared truss - a supporting piece - on the bridge that runs between Bucks County in Pennsylvania and Burlington County in New Jersey shows signs of holes that had been mistakenly drilled into the steel beam and then filled with plug welds, a typical solution in the 1950s when the bridge was built, said Karl Frank, professor emeritus of engineering at the University of Texas at Austin. His areas of study include fractures and fatigues in metal structures, welded and bolted joints.
Before Repair
After Repair
IntelliOptics® structural health monitoring software, developed by ChM4 a powerful, user-friendly interface that collects data from multiple sensor types and displays status information via one centralized program. We currently have a five year contract to support this system using our Azure Cloud based Website to monitor the bridge long term. The video clip gives a brief tour of the software and invite you to review its features. The Cloud automated reporting service emails weekly summary reports, an immediate text and email alert levels should limits for sensors exceed the protocol values assigned by the WSP engineers. Also see our software section on hosting services for more information and our Intelli-Insight® predictive analysis module for maintenance of critical structures.
IntelliOptics® structural health monitoring software using our Azure Cloud based Website to monitor the bridge engineers can directly log into the remote master control panel at the bridge to do other evaluations through the Azure website. One feature shown here is using cameras the WSP engineer controls and chose various combinations of Luna's os7510 accelerometers to compare the 8 zones and how traffic effect signatures of the bridge by viewing different traffic conditions/patterns and seasonal environmental changes.
Models built by WSP used by ChM4 for pre-assemble of sensor system and location approvals. The model also used in the cloud SQL user interface software IntelliOptics®.
ChM4 and WSP installing structural health monitoring cameras using a platform scissor lift.
Pennsylvania Approach SHM camera Video streamed to the cloud can respond to various zone warning Alert Areas.
New Jersey Approach SHM camera Video streamed to the cloud can respond to various zone warning Alert Areas.
ChM4 and WSP Splicing teams are important working together to efficiently splice main pre-assembled sensor arrays. This video is sped up but a 4 to 5 minute time frame was typical per splice location.
ChM4 and WSP used 4 types of access vehicles. Large platform scissor lift for camera placement on east and west portals, Under Bridge Access equipment (UBA) for areas higher than 145 feet with extreme terrain irregularities and two types of self propelled boom lifts, (2) 145 foot straight boom and (2) 125 foot three knuckle booms with jibs.
ChM4 designed DRB SHM control panels with environmental controls and redundant communications utilizing landline ethernet and cellular for backup. The system has a temporary UPS to accommodate a switch over to a diesel generator should all power be lost from the public metered power. The system has PC, monitor, keyboard and mouse with (2) Luna SI255 Data acquisition units gathering data from a large number of optical sensors. The sensors that make up of this system are Luna (158) os3155 strain sensors with on board temperature compensation, (16) os4350 absolute air temperature sensors for environmental purposes, (28) os7510 single axis accelerometers to obtain signature of key support span beams and (18) Technica T520 +/- 10 degree oil filled tilt sensors for 18 sets of rocker arm bearing to understand expansion joints movements. The total number of optical sensors including opposing or temperature compensation is (396) FBG sensors. The power behind optical sensors is they are passive requiring no power and all data gathered from one control panel requiring power at this location only.
ChM4 example design drawings used to build and install the DRB SHM system with sensor examples..