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Elastomeric Bearings - Ltbp Protocol - Fld-Dc-Vib-001

Publication Number: FHWA-HRT-16-007 Date: January 2016

Publication Number: FHWA-HRT-16-007
Date: January 2016

Long-Term Bridge Performance (LTBP) Program Protocols, Version 1

Visual Inspection—Bearings Protocols (VIB)

FLD-DC-VIB-001, Elastomeric Bearings

FLD-DC-VIB-002, Rocker Bearings

	Elastomeric Bearings LTBP Protocol #: FLD-DC-VIB-001

1. Data Collected

1.1

General condition of elastomeric bearings and surrounding components, including:

1.1.1

Bulging, splitting, and/or tearing of the neoprene pad.

1.1.2

Condition of the steel reinforcing plates (if visible) if the bearing is a laminated neoprene pad.

1.1.3

Longitudinal/lateral displacements and rotation of the neoprene pad.

1.1.4

Excessive strain due to growth in the lengths and widths of unlaminated (plain) neoprene pads.

1.1.5

Connections between the neoprene pad and the sole plate and masonry plate, between the sole plate and the beam bottom flange, and between the masonry plate and the pier or abutment.

1.1.6

Cracking, spalls, or delaminations in the abutment seat or pier cap.

1.1.7

Condition of the anchor bolts.

2. Onsite Equipment and Personnel Requirements

2.1

Equipment:

2.1.1

PRE-PL-LO-004, Personal Health and Safety Plan.

2.1.2

Ladder, access platform, snooper, bucket truck, man lift, and/or high-reach equipment (if necessary).

2.1.3

Wire brush or hand broom.

2.1.4

Tape measure.

2.1.5

6-ft folding rule.

2.1.6

Crack gage.

2.1.7

Slide caliper.

2.1.8

Digital level.

2.1.9

Plumb bob.

2.1.10

Laser measuring device (optional).

2.1.11

Hand compass or other angle-measuring device.

2.1.12

Thermometer.

2.1.13

Mirror.

2.1.14

Temporary marker.

2.1.15

Digital camera.

2.1.16

Pencil, sketch pad, and clipboard.

2.2

Personnel: PRE-PL-LO-005, Personnel Qualifications.

3. Methodology

3.1

Use the segmentation and numbering system for the superstructure (FLD-OP-SC-002, Structure Segmentation and Element Identification System) to identify the bearings being evaluated.

3.2

Measuring, recording, and evaluating characteristics of bearings:

3.2.1

Record the ambient temperatures above the deck and at the location of the bearing at the time of visual inspection.

3.2.2

Record if the bearing is a fixed or a moveable bearing. Examine the bearing. If it is a moveable bearing, does it still allow movement?

3.2.3

Record if the bearing is still in its proper alignment.

3.3

Measuring, recording, and evaluating characteristics of neoprene:

3.3.1

Use a wire brush or hand broom to clean the bearing area to allow close visual inspection.

3.3.2

Record if the elastomeric bearing is a plain neoprene pad or a laminated neoprene pad.

3.3.3

Measure bearing thickness, length and width, and any longitudinal and lateral displacements or rotations.

3.3.4

Examine the neoprene pad (plain or laminated) for defects on contact surfaces, bulging and split or torn surfaces, and excessive longitudinal and/or lateral displacements and rotations.

3.3.4.1

If there are splits or tears in the neoprene, check for steel shim exposure and condition, if exposed.

3.3.4.2

If there are splits in the neoprene, measure the length, width, and depth of each split.

3.3.4.3

If there is bulging, measure the amount of bulge using the slide caliper.

3.3.4.4

To determine rotation, measure the displacement of the top of the bearing face versus the bottom of the bearing face.

3.3.4.5

Use a mirror, if necessary, to examine the vertical surface of the bearing closest to the abutment backwall.

3.3.5

Is there a restraining device to keep the neoprene pad from moving horizontally from its original position? If so, record it and take a photograph of a typical restraining device.

3.4

Measuring, recording, and evaluating characteristics of the sole plate:

3.4.1

Examine the connection of the sole plate to the girder. Record any loss of bond and connection between the sole plate and the girder.

3.4.2

Examine the sole plate, and record any cracks, corrosion, and/or section loss of the sole plate.

3.5

Measuring, recording, and evaluating characteristics of the masonry plate:

3.5.1

Examine the connection of the masonry plate to the bearing device and the masonry plate to the abutment or pier. Record any loss of connection.

3.5.2

Examine the masonry plate, and record any cracks, corrosion, and/or loss of section.

3.6

Measuring, recording, and evaluating characteristics of the anchor bolt:

3.6.1

Examine the anchor bolts connecting the masonry plate to the pier or abutment. Record the diameter of the bolts.

3.6.2

Record any missing bolts, nuts, or washers.

3.6.3

Record any rust or corrosion of the bolts.

3.6.4

Examine the concrete around the anchor bolt and record if any part of the main body (shank) of the anchor bolt is exposed.

3.7

Measuring, recording, and evaluating characteristics of concrete surface (under and next to the bearing):

3.7.1

Check the condition of the concrete surfaces under and next to the bearing and record any defects.

3.7.2

Check for spalls and/or cracks in the pier or abutment top surface.

3.8

Documenting defects:

3.8.1

Take photographs of defects using FLD-DC-PH-002, Photographing for Documentation Purposes, and create a photo log.

3.8.2

Use sketches to document spalls and cracking and supplement the photographs.

3.9

Storing data, documents, and images:

3.9.1

FLD-DS-LS-001, Data, Document, and Image Storage—Local, for local storage.

3.9.2

FLD-DS-RS-001, Data, Document, and Image Storage—Remote, for remote storage.

3.10

Reporting: Transfer all metadata, data, documents, and images to Federal Highway Administration (FHWA), and/or upload all metadata, data, documents, and images into the Long-Term Bridge Performance (LTBP) Bridge Portal.

4. Data Collection Table

4.1

Table:

#	Field Name	Data Type	Accuracy	Unit	Field Description	Row Color
1	State	Text			State Code, e.g., Virginia = VA	Green
2	NBI structure number	Text			Item 8, Structure Number from NBI Coding Guide	Green
3	Structure name	Text			Descriptive name for the bridge, e.g., Route 15 SB over I–66	Green
4	Protocol name	Text			Title of the protocol	Green
5	Protocol version	Text	Month and year		Month and year the protocol version was published; e.g., May 2015	Green
6	Personnel performing data collection activities	Text			First name(s) Last name(s)	Green
7	Date data were collected	Text	Exact Date		mm/dd/yyyy	Green
8	Ambient temperature above deck	Number	1	°F		Green
9	Bearing number	Text			Evaluate and record data for each individual bearing	Blue
10	Ambient temperature at bearing location	Number	1	°F		Yellow
11	Is the bearing fixed or moveable?	Predefined list			Fixed or Movable	Yellow
12	If it is a moveable bearing, does it still allow movement?	Predefined list			Yes, No, or Not Applicable	Yellow
13	Is the bearing still in its proper alignment?	Predefined list			Yes or No	Yellow
14	Is bearing plain neoprene pad or a laminated neoprene pad?	Predefined list			Plain or laminated	Yellow
15	Neoprene condition	Text			Indicate no visible defects or document the presence of splits or tears, bulging, steel shim (plate) exposure, corroded shims (steel plates), presence of oxidation, and/or other defect (specify under comments)	Yellow
16	Sole plate connection to girder—surface bond condition	Text			Indicate no visible defects or document the presence of bond or no bond, movement of sole plate, and/or other defect (specify under comments)	Yellow
17	Sole plate condition	Text			Record any corrosion or section loss	Yellow
18	Masonry plate connection to the abutment or pier	Text			Record any loss of connection	Yellow
19	Masonry plate condition	Text			Record any corrosion or section loss	Yellow
20	Diameter of anchor bolts	Number	0.125	in.		Yellow
21	Condition of the anchor bolts	Text			Record any missing bolts, nuts, or washers; any rust or corrosion of the bolts; if the anchor bolt is partially exposed	Yellow
22	Condition of the concrete under and next to the bearing	Text			Indicate no visible defects or document the presence of shear cracks, spalling, on abutment seat or pier cap, and/or other defect (specify under comments)	Yellow
23	Rotation of neoprene pad	Number	1	Degrees		Yellow
24	Longitudinal displacement of neoprene pad	Number	0.125	in.		Yellow
25	Lateral displacement of neoprene pad	Number	0.125	in.		Yellow
26	Length of neoprene pad	Number	0.125	in.		Yellow
27	Width of neoprene pad	Number	0.125	in.		Yellow
28	Height (thickness) measurement of pad	Number	0.125	in.		Yellow
29	Defect photos	BLOB				Yellow
30	Comments	Text				Orange

4.2

Table Key:

Column Descriptions
#	Sequential number of data item
Field Name	Data field name
Data Type	Type of data, such as text, number, predefined list, binary large object (BLOB), or PDF file
Accuracy	Accuracy to which the data are recorded
Unit	Unit in which a measurement is taken and recorded
Field Description	Commentary on the data or list of items in a predefined list
Row Color Key
Green	Data items only entered once for each protocol for each day the protocol is applied
Pink	Logical breakdown of data by elements or defect types (not always used)
Blue	Data identifying the element being evaluated or the type of defect being identified
Yellow	LTBP data reported individually for each element or defect identified
Orange	Comments on the data collection or data entered

5. Criteria for Data Validation

5.1

Compare measurements with measurements from previous inspections of the same structure to make sure that values make sense.

5.2

Compare measurements with photo documentation to make sure results shown in photos are consistent with items measured.

5.3

If an element’s condition is improved when compared to the condition documented in a previous inspection, check with the State department of transportation to determine if any maintenance, repair, and/or bridge preservation actions have occurred. If so, document these maintenance, repair, and/or bridge preservation actions using appropriate protocols.

6. Commentary/Background

6.1

This protocol provides guidance on evaluating the condition of elastomeric bearings and for collecting data that help determine if the bearing is functioning as intended.

6.2

Elastomeric bearings are either reinforced (laminated) or nonreinforced (unlaminated). Steel plates (shims) are used as the reinforcing material in the rubber (neoprene) pad.

6.3

Sole plates are attached to the underside of bridge girders and transfer the force from the bridge girder to the bearing device.

6.4

The bearing device sits on top of a masonry plate. Masonry plates are attached to piers and abutments and transfer the force from the bearing device to the pier or abutment.

6.5

Anchor bolts are used to attach the masonry plate to the pier or abutment. The body of an anchor bolt (shank) should not be visible. Only the head of the anchor bolt, a nut, and a washer should be visible. If the body (shank) of the anchor bolt is visible, then the anchor bolts are said to be exposed.

7. References

7.1

LTBP Protocols:

7.1.1

PRE-PL-LO-004, Personal Health and Safety Plan.

7.1.2

PRE-PL-LO-005, Personnel Qualifications.

7.1.3

FLD-OP-SC-002, Structure Segmentation and Element Identification System.

7.1.4

FLD-DC-PH-002, Photographing for Documentation Purposes.

7.1.5

FLD-DS-LS-001, Data, Document, and Image Storage—Local.

7.1.6

FLD-DS-RS-001, Data, Document, and Image Storage—Remote.

7.2

External:

7.2.1

FHWA. (2012). Bridge Inspector’s Reference Manual – Report No. FHWA-NHI-12-053, Federal Highway Administration, Washington, DC.

Page Owner: Office of Research, Development, and Technology, Office of Corporate Research, Technology, and Innovation Management

Topics: research, infrastructure, structures
Keywords: research, structures, LTBP Program, bridge performance, bridge testing, bridge inspection, Bridge, bridge inspection, Long-Term Bridge Performance Program, LTBP, testing protocols, data collection
TRT Terms: research, infrastructure, Facilities, Structures
Scheduled Update: Archive - No Update needed

This page last modified on 03/24/2017

Long-Term Bridge Performance (LTBP) Program Protocols, Version 1

Visual Inspection—Bearings Protocols (VIB)

Elastomeric BearingsLTBP Protocol #: FLD-DC-VIB-001

1.

Data Collected

2.

Onsite Equipment and Personnel Requirements

3.

Methodology

4.

Data Collection Table

5.

Criteria for Data Validation

6.

Commentary/Background

7.

References

Elastomeric Bearings
LTBP Protocol #: FLD-DC-VIB-001