PE PDH
PDH Online

Bridge Inspection


Quiz Questions

1.There are basically 4 types of structural framing systems for the bridges, simple span, continues spans, cantilever and suspended spans, and rigid frame.
True
False
2. The substructure includes those parts, which transfer the loads from the bridge span down to the supporting ground.
True
False
3.Abutments are substructures supporting the end of a single-span or the extreme end of a multi-span superstructure and usually retaining or supporting the approach embankment. Typical abutments are shown in fig 3-2.
True
False
4.Piers transmit the load of the superstructure to the foundation material and provide intermediate supports between the abutments.
True
False
5.Bearings transmit the superstructure loads to the substructure, and they permit the superstructure to undergo necessary movements without developing harmful overstresses.
True
False
6.Dolphins and fenders around the bridges protect the structure against collision by maneuvering vessels.
True
False
7.The surface appearance of cracks on the bridge can give the first indication of the cause of cracking
True
False
8.Figure 5-1 shows a typical Pattern or Map crack, which are the result of restraint of contraction of the surface layer or possibly an increase of volume in the interior of the concrete.
True
False
9.Figure 5-2 shows D-cracking, these cracks usually start in the lower part if a concrete slab adjacent to joints, where moisture accumulates and progresses away from the corners of the slab. Vertical cracks near vertical expansion joints in the abutments and walls can also be classified as D-cracks.
True
False
10.The individual cracks that run in a definite directions and may be multiple cracks in parallel at definite intervals, indicate tension in the direction perpendicular to the cracking.
True
False
11.Spalling is defined as the development of fragments, usually in the shape of flakes, detached from a larger mass. Spalling differs from disintegration in that the material being lost from the mass is concrete and not individual aggregate particles that are lost as the binding matrix disintegrate.
True
False
12.Table 5-1 summarizes the various causes of:
Deterioration in concrete
Spalling
Soil erosion
13.Which one of the following could be cause of deterioration in steel bridges?
Air and moisture
Industrial fumes
Deicing agents
Seawater and mud
Thermal strain or overloads
Fatigue and stress concentration
Fire
Collisions
Animal waste
Welds
Galvanic action
All of the above
14.While timber is not as strong as steel, it approximates ordinary concrete in compressive strength. It’s rated strongest in flexural strength. Timber has an allowable compressive strength (parallel to wood grain) of about 75 percent of the flexural value. Perpendicular to the grain, compressive strength is only 20 percent of the flexural strength. Horizontal shear is limited to 10 percent of the flexural strength.
True
False
15.Common rules for timber repairs are:

  • There should be at least 1/8-inch clearances between the timbers to allow the timber to dry properly.
  • When native logs are used for construction, all bark should be removed to reduce moisture penetration into the logs.
  • Green or wet timber shrinks considerably when seasoned. Repeated wetting and drying also causes dimension changes as great as 5 to 10 percent in the direction perpendicular to the growth rings. Frequent re-nailing and tightening of bolts is necessary.
  • Care should be taken when using new and salvaged wood together to carry loads because of a difference in the sag and shrinkage of the members. The repair should avoid using new and old stringers in the same panel.
  • Wood shims or wedges should be made from heart cypress, redwood, Douglas fir, or of the same material as the member.
  • Replacement members must have the same dimensions as the existing member accounting for shrinkage.
  • Always treat drill holes and cut ends, to prevent water or insect damage.
True
False
16.When lumber is damaged to the point that the structural integrity of the member is in question, scabbing or slicing of the member may be required to bridge the damage.
True
False
17.In method of flexible sealing repair of a crack in concrete, it involves
routing and cleaning the crack and fitting it with a field-molded flexible sealant. It is used for active cracks in which the crack is the indication of a joint requirement in the concrete, and the formation of a joint does not impair the capacity of the structure.
True
False
18.Stitching is the process of drilling holes on both sides of the crack and grouting in stitching dogs (U-shaped steel bars with short legs) that bridge the crack.
True
False
19.Stitching is used to re-establish:
Tensile strength across the crack
Compressive strength across the crack
20.The typical repair involving concrete columns and piles is to place a concrete jacket around the member to protect it from further deterioration or to restore the structural integrity of the member. The repair can be made with a standard wood or metal formwork, which is removed after curing, or fiberglass form that remains in place and helps protect the surface of the member.
True
False
 
21.The large variety of crack types prevents a single repair method. Active cracking may require strengthening of the concrete across the crack to prevent further crack expansion and the application of a flexible sealant that will expand with the crack. Dormant cracks basically require bonding across the crack for the load carrying portion of the concrete and sealing in all other areas.
True
False