MATC Fall Lecture Series: Steve Garbe

Bridge Security and Bridge Health Monitoring

Presented bySteve Garbe P.E., Iteris

Clarification

If you tuned in to learn a lot about I-74… I apologize!

I-35W Overview• Basic ITS Elements

– 4 CCTV– 2 Ramp Meters– 1 Traffic Monitoring Location– 1 Existing DMS– 1 Existing Traffic Monitoring Location

• Unique Elements– 2 FLIR Cameras– Anti-Icing System– Bridge Security– SMART Bridge System– Aesthetic Lighting

4

Location

5

Concept to Reality

Rapid Changes

• Open Rail for the Outside Barrier

• 2 Ponds Introduced

• Pedestrian Underpass

• Limited ROW along the Bridge approaches

Concept to Reality

48 Fiber Optic Cable on the West Side of the Bridge96 Fiber Optic Cable on the East Side of the Bridge

• Typical Bridge Deflection of 13 inches

• Non-Metallic Conduit can move 2-4” every 100’ due to thermal expansion

Conduit Routing

Conduit Routing 4 Conduits in each Bridge Pier

for Communications & Power

Conduit Routing 4 Conduits in each Bridge Pier for

Communications & Power

Significant Design that included multiple systems:

Anti-IcingBridge SecurityITS communications120/240V for ITS Power480V for Street Lighting

Conduit Design

Conduit Complete

Although a pressurized system, portions of the ant-icing are designed on grade.

Anti-Icing Systems

MnDOT FLIR REQUIREMENTS:

• 1. System will detect and validate motion based on object size and trajectory. 2. System must be able to detect motion from cameras using minimum of 7 pixels.3. System must be able to track objects in motion with both fixed cameras and pan tilt zoom cameras with extraneous motion in the background.4. System must be able to detect, validate and track objects using thermal imaging cameras at ranges of at least 1470 feet.

Forward Looking Infrared CCTV

Forward Looking Infrared CCTV

Sensors for Structural BehaviorCHLORIDE SENSOR

Monitor levels of chlorides in the concrete deck to assist with maintenance activities

Sensors for Structural BehaviorACCELEROMETER

Accelerometers monitor bridge deflections under loads

Sensors for Structural BehaviorLINEAR POTENTIOMETER

Placed at expansion joints and bearings to measure bridge movements which can be compared to expected values

Vibrating wire strain gauges, installed in select locations, will measure how the bridge is resisting loads and also the

temperature of the concrete

Sensors for Structural Behavior VIBRATING WIRE STRAIN GAUGES with TEMPERATURE

Truck Loading Calibration

Anti-icing pumphouse not large enough for all communication termination and integration.

Field Integration

ITS Field ElementsBridge SecurityIP Addressable Lights

• The benefit of these type systems is significant:

Real-Time DataResearch

Program for Technology

• The cost is typically less than 2% of a large river bridge replacement.

Slide design © 2009, Mid-America Transportation Center. All rights reserved.

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