Minnesota Department of Transportation

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Strain [Concrete]

Staff member installing sensors

Strain [Concrete]

Concrete Embedment Strain Gauge - CD

Description
A "CD" sensor measures concrete pavement (PCC) strain response due to dynamic loads. The Concrete Embedment (CD) strain sensor is an electrical resistance strain gauge embedded within a strip of glass-fiber reinforced epoxy, with transverse steel anchors at each end of the strip to form an H-shape.

Manufacturer
Model PAST-2PCC manufactured by Dynatest.

Location and Quantity
CD sensors are embedded into the concrete surface layer near the top and bottom of the slab at various locations throughout a particular panel.

There were originally 128 CD sensors located in 8 MnROAD PCC test cells.

Current Status
These sensors were extracted (within cores) in 2003.

MnROAD Database Table
Data was collected during various load response testing sessions, and some has been processed and loaded into the MnROAD database. Data is located in database tables named: MNR.DYNAMIC_LOAD_TEST_VALUES and MNR.DYNAMIC_LOAD TEST DESCRIPTIONS. 

Concrete Embedment Strain Gauge - CE

Description
A "CE" sensor measures concrete pavement (PCC) strain response due to dynamic loads. The Concrete Embedment (CE) strain sensor is an electrical resistance strain gauge hermetically sealed between two thin resin plates.

Manufacturer
Tokyo Sokki Kenkyujo model PML-60 purchased from Texas Measurements, Inc.

Location and Quantity
CE sensors are embedded into the concrete surface layer near the top and bottom of the slab at various locations throughout a particular panel.

There were originally 436 CE sensors installed into 14 MnROAD PCC test cells. Newer PCC and Composite test cells at the MnROAD facility have included the installation of additional Tokyo Sokki model PML-60 strain sensors.

Current Status
The original (1993) sensors were removed by coring in 2003. Newer sensors remain in service.

MnROAD Database Table
Data continues to be collected during various load response testing sessions, and some has been processed and loaded into the MnROAD database. Data is located in database tables named: MNR.DYNAMIC_LOAD_TEST_VALUES and MNR.DYNAMIC_LOAD TEST DESCRIPTIONS.

CS Sensor

Description
A "CS" sensor measures concrete pavement (PCC) strain response due to dynamic loads. The Concrete Surface (CS) strain sensor is an electrical resistance foil type strain gauge mounted to a backing material suitable for bonding to a smooth concrete surface.

Manufacturer
Tokyo Sokki model FLM-60-11 purchased from Texas Measurements, Inc.

Location and Quantity
CS sensors were bonded to the side of concrete slabs at various depths.

Current Status
Some sensors remain in service.

MnROAD Database Table 32
Data continues to be collected during various load response testing sessions, and some has been processed and loaded into the MnROAD database. Data is located in database tables named: MNR.DYNAMIC_LOAD_TEST_VALUES and MNR.DYNAMIC_LOAD TEST DESCRIPTIONS.

Geokon Dynamic Strain Gauge - GD

Description
A "GD" sensor measures PCC strain response due to dynamic loads. The Geokon dynamic (GD) concrete embedment strain sensor consists of a full bridge gauged proving ring, coupled between two flanges.

Manufacturer
Geokon model 3900 manufactured by Geokon, Inc.

Location and Quantity
Two GD sensors are embedded into the concrete surface layer near the top and bottom of the slab, in the wheelpath of one panel in Test Cell 60.

Current Status
These sensors continue to function.

MnROAD Database Table
Data continues to be collected during various load response testing sessions, and some has been processed and loaded into the MnROAD database. Data is located in database tables named: MNR.DYNAMIC_LOAD_TEST_VALUES and MNR.DYNAMIC_LOAD TEST DESCRIPTIONS

Concrete Embedment Strain Gauge - MM

Description
A "MM" sensor measures PCC strain response due to dynamic loads. The Micro-Measurements Concrete Embedment (MM) strain gauge is an electrical resistance strain-sensing grid hermetically sealed within a polymer concrete casing.

Manufacturer
Micro-Measurements models EGP-5-120 and EGP-5-350.

Location
MM sensors are embedded into the concrete surface layer near the top and bottom of the slab at various locations throughout a particular panel.

Current Status
These sensors are no longer functional.

MnROAD Database Table
Data was collected during various load response testing sessions, and some has been processed and loaded into the MnROAD 33 database. Data is located in database tables named: MNR.DYNAMIC_LOAD_TEST_VALUES and MNR.DYNAMIC_LOAD TEST DESCRIPTIONS.