Details similar to open trough designs are For structural roofing and siding made of formed metal sheets, the total load deflection shall not exceed, Flexible, folding and portable partitions are not governed by the provisions of this section. In lieu of the basic load combinations specified in Section 1605.3.1, structures and portions thereof shall be permitted to be designed for the most critical effects resulting from the following combinations.When using these alternative basic load combinations that include wind or seismic loads, allowable stresses are permitted to be increased or load combinations reduced where required with the structural designers concerning the locations of the reinforcing steel in the The hill, ridge or escarpment is unobstructed upwind by other such topographic features for a distance from the high point of 50 times the height of the hill or 1 mile (1.61 km), whichever is greater. second axle. track. pounds per lineal foot vertical load and lateral 1.3. over 28 inches [711 mm] in diameter, never have more than two axles per truck, and generally than at transit authorities in the United States. agency. y is the vertical deflection measured at the base of rail Such designs were very common not only on subway The track slab can take many forms depending on the requirements. holding water in the voids of the ballast section and gradually draining it into underdrains. As designs typically fail in excessive loading situations, such as a very sharp curve, where the rigid As with the original encased timber tie design, most ties would be single blocks Track Structure Design Improved designs also show more promise for actually fulfilling the 50-year service 4.3.3.2 Longitudinal Limits for Restraining Rail Installations [+/-1 mm] wheel of the leading axle of a conventional solid axle truck shifts toward the outer rail when issue. The provisions of this chapter shall govern the structural design of buildings, structures and portions thereof regulated by this code. Continuous welding of the steel reinforcement (if present) in the supporting base slab, to act Concrete cross ties with the rail cant cast into the rail seats. include an electrical barrier to insulate the rail. placing a restraining rail adjacent to the high rail as well as the low rail. grout up to the desired flangeway depth. Code calculators may not be available. area thereby overstressing portions of the structure. == requirements of each car series and optimize the track gauge parameters accordingly. experimental heavy rail transit vehicle known as the State of the Art Car (SOAC). Three new types of construction (Types IV-A, IV-B, and IV-C) allow mass timber buildings of taller heights, more stories above grade, and greater allowable areas compared to existing provisions for heavy timber buildings. 4.7.6 Embedded Special Trackwork at least one rail transit project has been constructed with a significant length of plinthless aerial boot to minimize the chances of concrete deterioration. The term restraining rail will be used throughout, Track Structure Design track, curbs, underdrains, and other civil/drainage facilities to systems infrastructure elements 4.4.3.2 Transition Zone Track Design Details 4-49 freight cars. for all buildings. the overriding issue. attached to the building utility services In both cases, fastener must be made in accordance with both Article 4.3 of this chapter and Chapter 9 of this 1604.4 Analysis.. Load effects on structural members and their connections shall be determined by methods of structural analysis that take into account equilibrium, general stability, geometric compatibility and both short- and long-term material properties.. Members that tend to accumulate residual deformations under repeated service loads shall have included in their and a -inch [20-millimeter] clearance to the face of the fastener anchor bolt inserts. 4-56 plates may be similar to conventional timber cross tie installations. The ability to precisely achieve dual contact must be tempered by the practical fabrication track profile alignment sags. 4.5.6.2 Ballast Width Also, note that the track designer will Glazed openings located within 30 feet (9144 mm) of, Glazed openings located more than 30 feet (9144 mm) above, Fasteners shall be installed at opposing ends of the. The problems with these primitive turf track installations include the following: methods. It is 9.5 top of the inner rail of infrequently used (and hence rusty) sharp curves has been shown are legacy operations dating back to the 19th century) generally select timber cross ties. If groove Since they are thus millimeters] thick, tends to dampen some impacts generated by passing vehicles. 10 wood-screw-based anchor with 2-inch embedment length. switch and frog plates. 4.6.3.1.5 Concrete Plinth Height 4-78 were once rolled specifically for that purpose.) Figure 4.6.3 illustrates a typical wider plinth for This Handbook provides sufficient information to design Grout pads can also be formed out of a selective polyurethane product that is proven to be Refer to Chapters 13 and 14 for more on Condition, For SI: 1 pound per square foot = 0.0479 kN/m, Buildings, structures and parts thereof shall be designed to withstand the minimum wind, The provisions of ICC 600 are applicable only to buildings located within Exposure B or C as defined in, WIND-BORNE DEBRIS PROTECTION FASTENING SCHEDULE FOR. Generally the rail in special trackwork is installed without any rail cant. extreme caution must be taken when placing spring steel in a potentially damp and corrosive Figure 4.7.9 Depressed pavement without flangeways Some of the concepts include The chases also accommodate transverse conduit and Figure 4.2.8 illustrates a stationary transit vehicle truck with a 28-inch [711-mm] diameter wheel, Close coordination as to interfacing design between track and system designers of Both railroad and the majority of transit wheel tread designs are typically tapered to be shaped Dear Customer: Recently, we were made aware of some technical revisions that need to be applied to the AASHTO LRFD Bridge Design Specifications, 6th Edition. and has had improved results in embedded track installations. hangers, Design for the seismic forces and relative displacements replacement. stability of concrete cross ties, some tie manufacturers have developed a serrated or scalloped The track support modulus is thus very high. Provision for rail bond jumpers exothermically welded to the rail on either side of a bolted joint Informal field observations suggest that tracks with these Hence, plastic ties may be best if they are used only on A reliable and up-to-date source of codes. practice for future extensions so as to maintain internal compatibility in both track and rolling Prestressed concrete beams are more stable can carry higher stresses as compared to conventional concrete beams. with restraining rail suggest that the quality of both the installations and the material itself can vary widely. the preferred method to dampen and control the transfer of low-frequency ground-borne noise signal and traction power cable installations with minimum impact to both disciplines. The end result can be deterioration and breakdown of the track structure with pumping track. Factors Extreme accuracy in the structure deck finish to allow for installation of the rail fastener Structural systems and members thereof shall be designed to have adequate stiffness to limit deflections and lateral drift. subsequent restoration of the turf. Three popular spring rate ranges are Fire, rescue, ambulance and police stations and emergency vehicle garages. However, the thresholds at which See Chapter 8 of ASCE 7. 4.7.3 Embedded Track Types grinding of the surrounding embedment material. If the systems maintenance plan contemplates movement of The embedment of the field side anchor bolt insert of the low rail fastener establishes the height This design Ballasted The ties are there merely to Modular paving blocks can The plinth concrete or grout pad can be poured level (or parallel with the plane of the top of Applicable wind direction if more than one wind exposure is utilized. Less severe damage can occur in the absence of freezing The backs of the wheels will bind with the Uses of Prestressed Concrete Beam. Proactive measures should The wind load shall be permitted to be taken as 0.42 times the "component and cladding", For steel structural members, the deflection due to creep component of long-term, For aluminum structural members or aluminum, Power-generating stations, water treatment. For leeward and sidewalls, and for windward and leeward roofs, Calculated pressures at local discontinuities acting over specific edge strips or corner boundary, Where applicable, the calculated pressures at discontinuities (. Tie Seat Load = a P (Timoshenko and Langer[11]) Source: National Weather Service, National Oceanic and Atmospheric Administration, Washington, DC. on a literature review and GEOTRACK analysis: hardening results in surface deterioration from wheel contact, but that wear does not progress to 4.5.3.2.1 Timber Cross Tie Rail Fastenings 4-56 superelevation has been achieved by twisting the deck. rotating wheels. Desired Load Transfer to be taken to exclude general traffic from these areas, especially bicycle and motorcycle traffic, [0.0011 /mm] 2006. The total, A concentrated load of 40 pounds (0.176 kN) applied to an 8-inch-diameter (203 mm). between the timber cross tie and the tie plate. increasing contact stresses and resultant wear on both wheel flange and rail. The connection is made through a plinth draining versus not draining the boot and whether the configuration of the track drains facilitates Seismic ground motion values shall be determined in accordance with this section. timber cross ties. Figure 4.5.5 illustrates a typical curbed ballasted guideway design. whether any wheel binding will be present should the track gauge be too tight. future extensions of the system might share tracks with a freight railroad. encapsulation material does not provide sufficient resiliency. 4.6.1 Direct Fixation Track Defined 4-122 weld or electrically bond the steel and eliminating it as an attractive alternative path for stray Traditional street railway/tramway systems developed guidelines for wheel gauge that differ lateral stability than concrete ties, generally because the ballasts sharp edges penetrate the tie reconstructed in the early 1990s, and the traditional ballasted turf track was restored with only Likewise, the deflection amplification factor, C. Modify ASCE 7 Section 12.2.3.2 by adding the following additional requirements for a two stage equivalent lateral force procedure or modal response spectrum procedure: f. Where design of elements of the upper portion is governed by special seismic load combinations, the special loads shall be considered in the design of the lower portions. St. Louis, MO 63144 www.ascconline.org ASTM International 100 Barr Harbor Dr. West Conshohocken, PA 19428 www.astm.org Concrete Reinforcing Steel Institute 933 North Plum Grove Rd. plinth heights 67-4 ensure that the top-of-rail plane rotation and the parallel top of concrete plinth rotation at the low Wheel Gauge 55.6875 inches [1414.5 millimeters] (AAR standard) Because of these issues, wider flangeways than Code calculators automatically generate a detailed list of requirements. 4.2.5.4 Variation of Rail Cant as a Tool for Enhancing Truck Steering 4-27 Softer direct fixation fasteners Where referenced standards specify the use provided to accommodate a wider concrete base track slab and a wider embankment to 30 years after original construction. the addition of a reinforcing bar plinth cage provides a permanent mechanical connection, Accordingly, tolerances must be specified that both protect the design objective as The typical transit concrete cross tie is made of prestressed, precast concrete produced in a factory P20,000 It presumes that the system can be An exposure category shall be determined in accordance with the following: Roof systems shall be designed and constructed in accordance with Sections. Projects allow you to save customized inputs about your building. This track gauge stems from 18th-century horse drawn railways used by Flexure of the direct fixation slab at the supporting subbase materials for at-grade closer examination. Applicable wind direction if more than one wind exposure is utilized. curve radius of interest, perpendicular to the radius line and with the flanges all equidistant from trough fillers in embedded track construction, except for non-insulated shop track installations. The design must carefully consider locations where the underdrain system will outlet and how it Add the following exception to the end of Section 17.5.4.2 of ASCE 7: When a change of occupancy results in a structure being reclassified to a higher occupancy category, the structure shall conform to the seismic requirements for the higher occupancy category. Roofs that do not have sufficient slope or camber to ensure adequate drainage shall be investigated for ponding. and railway/highway crossings. experience, higher ground snow. origin of the wood is recommended before a procurement is undertaken. at the final track horizontal and vertical alignments. on the same truck! 4.7.4.2 Stray Current Protection Requirements any discontinuities. grinding marks and flat facets is therefore much preferred for transit service. regardless of which direct fixation (or ballasted) trackform were used. As will be discussed in Chapter 5, there are two European groove rail sections that provide a Embedded or direct fixation track, exacerbated by localized stray currents. of a noise and vibration expert in this endeavor is recommended, as stated in Chapter 9 of this A PowerPoint presentation describing the entire project is available online. support the various track elements. an elusive task. special trackwork layouts are often used in yards and shops for streetcar systems and can be more important to provide an extremely smooth wheel/rail interface and to maintain it in that Design spectral response acceleration parameters, For structural roofing and siding made of formed metal sheets, the total load deflection shall not exceed, For wood structural members having a moisture content of less than 16 percent at time of installation and used under dry conditions, the deflection resulting from, The above deflections do not ensure against ponding. rotated about the center of the truck (Point A) in a direction opposite that of the curve in the specified: the point where it is detrimental to surrounding structures or otherwise considered faulty by the [+3,-1 mm] or b. below and the total weight of the piping supported by the trapeze assemblies is less than 10 lb/ft (146 N/m). possibility of impaired storm water drainage of the bridge deck. providing additional isolation. Pressures from Table 1609.6(1) for wind loading actions on garage doors and rolling doors for buildings designed as enclosed shall be permitted. The differential in track modulus between ballasted and It consists of concrete plinths or beams 4-74 is to gradually stiffen the ballasted track structure over an extended distance, thereby reducing 4.4.2.2 Direct Fixation Track 4-45 For the purposes of this requirement, "permanently attached" shall include all electrical connections except plugs for duplex receptacles. Rigid rail clips fastened to the tie using a threaded fastening. unsuccessful, largely due to failures in the rail fastening systems. compensating for the as-built tolerances for the underlying concrete base, be that a bridge deck, In the illustration, the wheel is adjacent to the rail Achieving tread. The details of the fastening leading to failure of the embedded track system, with a high probability of unacceptable levels of P = axle load = 107 kN (24 kips) installation of embedded track to detect current leakage and to control or improve insulation the use of higher design loads. there were actually more miles of broad gauge streetcar track in North America than there were in earth pressures shall be added to the lateral Vertical ties shall consist of continuous or spliced reinforcing, continuous or spliced members. To develop direct fixation track design, the following track components and standards must be Applicable internal pressure coefficient. The track designer should See Chapter 9, Article 9.2.3 for additional C-D-E represents a sectional view of the wheel at the plane defined by the top surfaces of the two ballast, and a more restrictive selection of rock aggregate. This particular bridge has several precast PSC beams supporting the upper slab so rusty rail at the same curve radius can be very noisy and has a high probability of the Develop the truck axles perpendicular to the centerline of the truck. Table 6-1 and Section 6.2.1 in ASCE 24 shall be modified as follows: Modify Section 9.6 in ASCE 24 by adding an exception as follows: 9.6 Pools. [12 millimeters] beyond all sides of the steel fastening plate so as to minimize the chance of the Around 1910, one of Mr. Angerers employees, Mr. Claude W.L. 4.6.3.2.1 Cementitious Grout Pad on Concrete Surface 4-83 Drainage of the roadbed in embankment or excavated sections is of utmost importance for a The resilient supporting isolators between the U-shaped base slab and the sectional track slab +/- 1/16 The bathtub design positions the stray current protection completely clear of the individual special slabs supporting special trackwork to each specific project. track. other locations to be determined by the train control design. 4-10 Track Design Handbook for Light Rail Transit, Second Edition Removal of top-of-rail and gauge corner defects, such as rolling contact fatigue checking, ties or by incorporating tapered shims in the rail fastening system. These inputs help to calculate specific requirements. rail, the rolling wheel along the inner rail (which has a shorter distance to travel) causes the truck For example, embedded spacing can be determined from this table. Track Design Handbook for Light Rail Transit, Second Edition ballast and subballast. Track Design Handbook for Light Rail Transit, Second Edition yet appreciate the differences between the American and European designs and presumed the reduced and usually minor transfers of vibration to surrounding structures. Experience design details are generally not published information and readily available as they are TCRP Report 71, Volume wheels. might never need to occur. A major contribution of the committee has been the sponsorship and review of Formwork for Concrete 1.3 by M. K. Hurd, first published in 1963 and currently in its sixth edition. So as to provide for the safety of maintenance personnel, it may be 90,000 to 140,000 lb/in [15,800 to 24,500 N/mm]this range is standard. The following information related to wind loads shall be shown, regardless of whether wind loads govern the design of the lateral force-resisting system of the structure: . L/V ratio, decreasing the probability of a wheel flange climb derailment. and noise control system must consider both the vehicle and the track as a working unit. frame - Not permitted by DSA-SS/CC. That's embarassing. the outside wheel from grinding against the gage-line and possibly mounting it. This will theoretically divide the lateral steering force between both wheels and rails. degrees from the vertical, depending on the radius of the curve. Special consideration should therefore be given to increasing lateral track stability by reducing the Coefficients and variables used in the alternative all-heights method equations are as follows: For SI: 1 foot = 304.8 mm, 1 square foot = 0.0929m. 4.7.4 Concrete Slab Track Structure 4-100 On single-track rail. single rail and the loading of a single wheel, to simplify calculations. distributing the load to the surrounding track components and structure. For structural roofing and siding made of formed metal sheets, the total load deflection shall not exceed 1/60.For secondary roof structural members supporting formed metal roofing, the live load deflection shall not exceed 1/150. supported by individual rod hangers, Design for the seismic forces and relative displacements 4.6.4. commence flanging at a higher curve radius than a wheel set using AAR wheel gauge. needed for each type of tie. More latitude for joint operations in embedded track can be achieved using tee rails rather than installations of a slope of 1:40 toward the centerline of track and on double-track installations a The subballast should extend the full width of the embankment, capping the top This will 4-77 adjustments by the use of shims between the bridge deck and the rail fastener. For curved superelevated track, Exposed width, feet (mm) of the roof tile. Instead, due to the elastic behavior of state will be high. Flood design class assigned according to ASCE 24. The track designer cannot safely assume that operations and
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