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Appendix F

Classification Examples

This appendix contains classification examples using the analytical classification procedure. Refer to Chapter 3 for a detailed discussion of the equations.

NOTATIONS

F-1. This appendix contains examples for classifying a bridge using the analytical classification procedure. The following notations are used in this appendix:



TIMBER-STRINGER BRIDGE

F-2. In this example, Table F-1 shows the procedure for classifying a timber-stringer bridge and Table F-2 contains a classification summary. Figure F-1 shows a sample bridge-reconnaissance report for a timber-stringer bridge. Information from an on-site inspection is as follows:

  • The bridge is in good condition.
  • All members are in good condition.
  • The piling and abutment end beams have been treated to reduce deterioration. Therefore, substructure is not rated.
  • The bridge is about two years old.
  • Each of the three spans are constructed identically, so the longer (17-foot) span will be classified as the weakest span.
  • The timber species is dense, select-structural Douglas fir.
  • The horizontal splits are no longer than 6 inches.

Figure F-1. Sample Bridge-Reconnaissance Report for a Timber-Stringer Bridge

Figure F-1. Sample Bridge-Reconnaissance Report for a Timber-Stringer Bridge

STEEL-STRINGER BRIDGE

F-3. In this example, Table F-3 shows the procedure for classifying a steel-stringer bridge and Table F-4 contains a classification summary. Figure F-2 shows a sample bridge-reconnaissance report for a steel-stringer bridge. Information from an on-site inspection is as follows:

  • The bridge is in excellent condition.
  • The date built is unknown.
  • The steel-stringer sections were identified by comparing dimensions with the section properties found in Appendix D.
  • The concrete deck does not act to increase the moment capability of the stringers. Therefore, it is noncomposite.

 

Figure F-2. Sample Bridge-Reconnaisance Report for a Steel-Stringer Bridge

Figure F-2. Sample Bridge-Reconnaisance Report for a Steel-Stringer Bridge

COMPOSITE STEEL-CONCRETE STRINGER BRIDGE

F-4. In this example, Table F-5 shows the procedure for classifying a composite steel-concrete stringer bridge and Table F-6 contains a classification summary. Figure F-3 shows a sample bridge-reconnaissance report, and Figure F-4 shows a composite section of this bridge. Information from an on-site inspection is as follows:

  • The bridge is in excellent condition.
  • Full lateral support of the stringers is provided by the connection with the concrete deck.
  • The steel-stringer sections were constructed from A36 steel (36 ksi yield), according to civilian authorities.
  • The concrete allowable stress is 4,000 psi (f'c = 4,000 psi; and rm = 8).
  • Scomposite denotes the composite section modulus as determined according to paragraph 3-75.

 

Figure F-3. Sample Bridge-Reconnaissance Report for a Composite Steel-Concrete Stringer Bridge

Figure F-3. Sample Bridge-Reconnaissance Report for a Composite Steel-Concrete Stringer Bridge

 

Figure F-4. Composite Section

Figure F-4. Composite Section

STEEL-GIRDER BRIDGE

F-5. In this example, Table F-7 shows the procedure for classifying a steel-girder bridge, and Table F-8 contains a classification summary for a steel-girder bridge. Figure F-5 shows a sample bridge-reconnaissance report for a steel-girder bridge. Figures F-6 and F-7 show details of the girder. According to civilian authorities, the deck is a concrete slab constructed of noncomposite construction.

 

 

Figure F-5. Sample Bridge-Reconnaissance Report for a Steel-Girder Bridge

Figure F-5. Sample Bridge-Reconnaissance Report for a Steel-Girder Bridge

 

Figure F-6. Detail of the Main Girder

Figure F-6. Detail of the Main Girder

 

Figure F-7. Moment of Inertia of the Rivet Holes

Figure F-7. Moment of Inertia of the Rivet Holes

TRUSS BRIDGE

F-6. In this example, Table F-9 shows the procedure for classifying a truss bridge. Table F-10 contains a classification summary. Figure F-8 shows a sample bridge-reconnaissance report for a truss bridge. Figures F-9 and F-10 show details of the bridge.

 

Figure F-8. Sample Bridge-Reconnaissance Report for a Truss Bridge

Figure F-8. Sample Bridge-Reconnaissance Report for a Truss Bridge

 

Figure F-9. Truss Details

Figure F-9. Truss Details

 

Figure F-10. Rivet Details

Figure F-10. Rivet Details

REINFORCED CONCRETE-SLAB BRIDGE

F-7. In this example, Table F-11 shows the procedure for classifying a reinforced concrete-slab bridge and Table F-12 contains a classification summary. Figure F-11 shows a sample bridge-reconnaissance report, and Figure F-12 shows the steel-reinforcement details of this bridge. The local civilian bridge authorities provided the following stress values:

  • Fy = 50 ksi (grade-50 bars).
  • f'c = 3 ksi.

Figure F-11. Sample Bridge-Reconnaissance Report for a Reinforced Concrete-Slab Bridge

Figure F-11. Sample Bridge-Reconnaissance Report for a Reinforced Concrete-Slab Bridge

 

Figure F-12. Steel-Reinforcement Details for a Concrete-Slab Bridge

Figure F-12. Steel-Reinforcement Details for a Concrete-Slab Bridge

REINFORCED CONCRETE T-BEAM BRIDGE

F-8. In this example, Table F-13 shows the procedure for classifying a reinforced concrete T-beam bridge and Table F-14 contains a classification summary. Figure F-13 shows a sample bridge-reconnaissance report, and Figure F-14 shows details of this bridge. The local civilian bridge authorities provided the following stress values:

  • Fy = 40 ksi (grade-40 bars).
  • f'c = 3 ksi.

Figure F-13. Sample Bridge-Reconnaissance Report for a Reinforced Concrete T-Beam Bridge

Figure F-13. Sample Bridge-Reconnaissance Report for a Reinforced Concrete T-Beam Bridge

 

Figure F-14. Steel-Reinforcement Details

Figure F-14. Steel-Reinforcement Details

REINFORCED CONCRETE-BOX-GIRDER BRIDGE

F-9. In this example, Table F-15 shows the procedure for classifying a reinforced concrete-box-girder bridge and Table F-16 contains a classification summary. Figure F-15 shows a sample bridge-reconnaissance report, and Figure F-16 shows details of this bridge from as-built civilian drawings. The local civilian bridge authorities provided the following stress values:

  • Fy = 50 ksi (grade-50 bars).
  • f'c = 4 ksi.

Figure F-15. Sample Bridge-Reconnaissance Report for a Reinforced Concrete-Box-Girder Bridge

Figure F-15. Sample Bridge-Reconnaissance Report for a Reinforced Concrete-Box-Girder Bridge

 

Figure F-16. Details From As-Built Civilian Drawings

Figure F-16. Details From As-Built Civilian Drawings

PRESTRESSED CONCRETE BRIDGE

F-10. In this example, the bridge deck is of composite construction. Since the 28-day compressive strength of the deck and stringers is the same, no transformed moment of inertia calculations are required. If the deck were made of ordinary-grade concrete and the precast, prestressed beam made of high-strength concrete, the different moduli of elasticity would have to be considered. Table F-17 shows the procedure for classifying a prestressed concrete bridge, and Table F-18 contains a classification summary. The detailed dimensions and information about the prestressed steel in Figure F-17 were taken from as-built drawings. Figure F-18 shows a sample bridge-reconnaissance report. The local civilian bridge authorities provided the following allowable stress values:

  • fpu = 240 ksi.
  • f'c = 5 ksi.

Figure F-17. Details of a Prestressed  Beam

Figure F-17. Details of a Prestressed Beam

 

Figure F-18. Sample Bridge-Reconnaissance Report for a Prestressed Concrete Bridge

Figure F-18. Sample Bridge-Reconnaissance Report for a Prestressed Concrete Bridge

MASONRY-ARCH BRIDGE

F-11. In this example, Table F-19 shows the measured bridge dimensions, Table F-20 shows the classification procedures, and Table F-21 shows a classification summary for a masonry-arch bridge. Figure F-19 shows a sample bridge-reconnaissance report. Tests show that the arch is made of blue engineering brick. The ring is in good condition with well-mortared joints (about 3/8-inch wide). A small transverse crack was noted within 2 feet of the edge of the ring and there is a slight vertical settlement at one of the abutments.

Figure F-19. Sample Bridge-Reconnaissance Report for a Masonry-Arch Bridge

Figure F-19. Sample Bridge-Reconnaissance Report for a Masonry-Arch Bridge



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