Page 39 - Bridge and Highway Structure Rehabilitation and Repair

14 SECTION 1 ADMINISTRATIVE ISSUES

Type 2
• Steel sliding on phosphor bronze
• Steel sliding on steel
• Steel sliding on lubrite.
Type 3
• Pot bearing with P.T.F.E. (Ex.Tefl on).
Type 4
• Multi-rotational (pot bearing) guided
• Multi-rotational (pot bearing) unguided
• Multi-rotational (disc bearing) guided
• Multi-rotational (disc bearing) unguided.
Type 5
• Elastomeric with P.T.F.E. (Ex. Tefl on)
• Elastomeric, fabric type with P.T.F.E. (Ex. Tefl on)
• Elastomeric, steel laminated
• Elastomeric, fabric laminated
• Elastomeric, steel laminated w/Ext. load plate
• Elastomeric, steel laminated w/lead core
• Elastomeric, laminated with P.T.F.E. (Ex. Tefl on).

1.5.2 Substructure Replacement
In the past, there has often been an over design by using gravity and massive wall type
abutments, piers, and their foundations. This had an in-built advantage in that when it came to
replacement, only the superstructure was replaced.
It is an unusual situation if the substructure needs to be replaced while the superstructure is
in satisfactory condition. In some cases, superstructures can be lifted off the bearings and reused.
In most cases, the entire bridge is replaced, except when using the roll in-roll out technique which
can preserve the superstructure.
1.5.3 Abutment Types

1. Cantilever wall:
• Full height abutment
• Mid-height abutment
• Stub and semi-stub abutments (shown in Figure 1.4).
2. Spill-through abutment.
3. Modern types are:
• Integral abutments
• Semi-integral abutments
• MSE (mechanically stabilized earth) wall abutments.

1.5.4 Pier Types

Multiple bents and flared caps are aesthetically pleasing. Common shapes are shown in
Figure 1.5 and include:
1. Solid wall
2. Hammerhead