Planning and Preliminary Design of Modern Railway Bridges - Design of Modern Steel Railway Bridges - page 83

early in the design process concerning rolled section and plate size availability from
steelmillsorsupplycompanies.Afterthecompletionoffabrication,marking,loading,
and shipping is arranged. Large steel railway spans may also require experienced
engineers to provide loading and shipping arrangements that ensure safety of the
fabricated structure, railway operations, and public.

3.3.7 E RECTION C ONSIDERATIONS
Erection of steel railway bridges may be by steel fabricator, general contractor, or
railroad construction forces. Steel span erection procedures and drawings should be
in conformance with the engineering design drawings, specifications, special provi-
sions, shop drawings, camber diagrams, match marking diagrams, fastener material
bills, and all other information concerning erection planning requirements. Erection
procedures should always be made with due consideration of safety and transporta-
tion interruption. The stresses due to erection loads in members and connections
may exceed usual allowable stresses by 25% in steel freight railway bridges. This
may be increased to 33% greater than usual allowable stresses for load combinations
including erection and wind loads (see Chapter 4). Field joints should be made in
order to connect the members without exceeding the calculated erection stresses until
the complete connection is made. Recommendations related to the erection of steel
freight railway bridges are also included in AREMA (2008). ∗

3.3.8 D ETAILED D ESIGN OF THE B RIDGE
Detailed design may proceed following all deliberations related to the railroad oper-
ating environment, site conditions, geometrics, aesthetics, superstructure type, deck
type, preliminary design of framing systems, fabrication, and erection are completed
to an appropriate level. † Detailed design will proceed from load development through
structural analysis and design of members and connections to prepare structural steel
design drawings and specifications for fabrication and erection of the superstructure
(see Chapters 4 through 9).

REFERENCES

Akhtar, M.N., Otter, D., and Doe, B., 2006, Stress-State Reduction in Concrete Bridges Using
Under-Tie Rubber Pads andWood Ties , Transportation Technology Center, Inc. (TTCI),
Association of American Railroads (AAR), Pueblo, Colorado.
American Railway Engineering and Maintenance-of-way Association (AREMA), 2008,
Manual for Railway Engineering , Lanham, Maryland.
American Society of Testing and Materials (ASTM), 2000, Standards A325 and A490 , 2000
Annual Book of ASTM Standards, West Conshohocken, PA.
American Welding Society (AWS), 2005, Bridge Welding Code , ANSI/AASHTO/AWS D1.5,
Miami, FL.

∗

Recommended practice for the erection of steel railway bridges is outlined in AREMA Chapter 15,
Part 4.

†

The level of planning and preliminary design effort is related to the scope, magnitude, and complexity
of the proposed bridge.