Page 38 - Bridge and Highway Structure Rehabilitation and Repair

CHAPTER 1 OVERVIEW OF BRIDGE ENGINEERING 13

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1'-7 1/2"

9" 1 1/2"

#5 BARS

6-#4 BARS IN BARRIER

#5 BARS AT X

NEW JERSEY TYPE CONCRETE PARAPET
Figure 1.3 Crash tested barriers require regular maintenance.

1.5 MAINTENANCE/REPLACEMENT OF THE SUBSTRUCTURE
1.5.1 Common Bearing Types
1. Rocker and roller bearings
2. Elastomeric pad
3. Multi-rotational
4. Isolation bearing
• New bearings are preferred over trying to repair existing bearings.
• Elastomeric pad bearings involve the least maintenance.
• If one bearing is defective, replacing the entire row may be considered due to uniform
performance.
• Use of a single row of bearings for continuity is the modern trend.
• The provision of vertical curves increases vertical clearance and allows navigation.
The following types of bearings are seen on U.S. bridges:

Type 1
• Steel roller
• Steel rocker.