Chapter 8, Part 22 of the AREMA Manual for Railway Engineering provides . Permitting of the Practical Guide to Railway Engineering) Simple economics may . Practical Guide To Railway Engineering Second Edition on *FREE * shipping on qualifying offers. Available now at – Hardcover – AREMA – – Book Condition: New – Practical Guide to Railway Engineering Print Hard Copy & CD.
|Published (Last):||8 May 2004|
|PDF File Size:||7.13 Mb|
|ePub File Size:||12.8 Mb|
|Price:||Free* [*Free Regsitration Required]|
However, in track constructed with concrete ties, the track is often times transitioned to timber ties before crossing the structure. The center of gravity of the structure is immediately over the bearing to ensure that the bridge is balanced when in the open position. Where a large portion of the longitudinal force is carried to the abutments or embankment, Chapter 7 allows neglecting longitudinal force in the design of piles, posts and bracing of bents.
Thus, interior vertical clearances must be considered in addition to side clearances. Chief among these are welded connections and continuous spans. Crib Walls Crib walls, also known as bin walls Figureare composed of interlocking prefabricated members arranged to form a series of cells or “bins,” that are then filled with compacted backfill. The lift machinery is mounted above the deck.
On open deck bridges, the stringers are chorded into a minimum of three engijeering generally four or more beams with each adjacent stringer joint offset by one span length from its adjacent neighbor stringers for three span or longer structures. In addition to the types of construction, the engineer must also choose from among the available material alternatives. Lateral loads from equipment are not included in the design of concrete bridges.
These spans are usually supported on a guice pivot pier as well as a circular track at the end of the span. The lateral forces parallel to the axis of the bridge are the train-produced longitudinal forces and the surcharge pressure from the earth due to both its weight and live load.
Typically, the counterweights are of concrete or steel-encased concrete construction. The first is vessel collision or, more correctly allison with piers.
A powered pinion gear See Figure engages a fixed horizontal rack gear attached to a frame on the adjoining span. False caps of varying thickness are used to shim up the height of the deck railday when required. Used in friction bearing alone, H- beam piles will generally require a greater length of penetration than a displacement type of pile of the same load-bearing capacity.
They are watertight to the extent required and need strength rialway resist pressures from the outside.
Practical Guide Table of Contents
Inthe Association of Telegraph and Telephone Superintendents was formed by the telegraph superintendents of the major railroads. It performs particularly well in seismic zones, due to the built-in flexibility of the system, which allows for some Figure MSE Green Wall – Courtesy of Charley Chambers engineefing without distressing the engineeting or causing cracks.
Steel piling, whether on dry land or in submerged locations, may be driven to form bents and encased in concrete to form a pier, thus enhancing the strength and providing protection for the steel. It is unlikely that the bridge was actually designed as an E structure.
Often, wooden cleats are used for splices to secure longer lengths when needed. This procedure repeats until the design height rai,way reached.
American Railway Engineering and Maintenance-of-Way Association
Even if no specific seismic analysis and design is required for a structure, it is good practice to detail structures for seismic resistance if they are in potentially active areas. Consideration is given to the proper balance between the costs of the substructure and the superstructure. With the advent of the high-adhesion AC locomotives, there is much concern in the industry that the AREMA-based design load percentage for longitudinal loading for timber structures, as recommended, may be significantly understated.
Exotic materials can also be considered, but they are beyond the scope of this book. The lowered counterweight must maintain clearance between other structural members of the bridge. MSE walls are well suited for restricted sites or close property lines since construction is performed behind the wall face without any forms or scaffolding. They are typically corrugated metal pipe with perforations along the bottom invert to allow drainage of the surrounding soil.
Other types, such as the toothed ring and the spike grid, are embedded in the timbers by means of pressure. As of the published date of this text, for purposes of bridge rating only, AREMA provides a reduction in impact design values for speeds less than 60 mph.
For these longer spans, a built up section Figure 8- 13 is more desirable as it produces a more efficient use of the material. Access to the tower is required to grease sheaves and service atema machinery.
American Railway Engineering and Maintenance-of-Way Association – Wikipedia
For spans less than feet in length, each track of a two-track structure will assume the full impact design lractical. Common beam sections are slabs, tees and voided single and double cell boxes Figure Ballast Deck In addition to the obvious weight and construction costs, each of the span alternatives has their unique safety, environmental and maintenance concerns. Chapters 8 and 15 also state that the longitudinal load is to be applied to one track only, and can be distributed to bridge components based on their relative stiffness and the types of bearings.
The impact design value may be reduced for a second track for spans greater than feet in length.
The frames are spaced to facilitate attachment of bracing between them. In general, reduction in live loading is allowed for members receiving live load simultaneously from three or more tracks to model the reduced probability of occurrence.
They may be composed of bents supported by suitable foundations, e. Trough Floors Figure Ballast Pan on Stringers – Courtesy of Metra The steel-trough bridge floor has been used in the past primarily for ballasted deck structures over city streets, particularly in connection with track elevation work. In some cases, concrete piles in lengths up to ft have been cast and driven successfully with special equipment required for driving. For multiple track structures, it may be prudent to include longitudinal force on more than one track, depending on the bridge location and train operation at the site.
It does in fact assume a base level of knowledge pertaining to the design of structures and bridge systems. It was used in for the Oahe Dam project in South Dakota. Framing the floor system involves significant detailing and fabrication and is not often performed. The ultimate limit state requires that the structure suffer only readily detectable and repairable damage during Level 2 ground motion.