using a deck overhang thickness of approximately ¾' to 1' thicker than the deck thickness has proven to be beneficial in past designs. for this example, an overhang thickness of 9 in., including the ½ in. sacrificial layer is assumed in the design. design step 4.4 concrete parapet. a type-f concrete parapet is assumed.
bridge deck overhang design 2/7/2018 3. barrier design forces. design forces and designations railing test levels tl-1 tl-2 tl-3 tl-4 tl-5 tl-6. ft transverse kips 13.5 27.0 54.0 54.0 124.0 175.0. fl longitudinal kips 4.5 9.0 18.0 18.0 41.0 58.0.
march 2010 lrfd bridge design 9-19. this example demonstrates the design of a typical reinforced concrete deck. the first part describes the design of the interior region of a reinforced concrete deck supported on beam or stringer elements. the second part provides design procedures for the deck overhang region.
the deck overhang is designed to resist an axial tension force from vehicular collision acting. simultaneously with the dead load moment. the design moment critical section shall be taken at one-. third of the flange width from the centerline of exterior girder aashto .6 .
prestressed concrete psc girder superstructure bridge design example - us units pdf version 1.7 mb steel girder superstructure bridge design example - us units pdf version 3.2 mb events
on a strht bridge slab edge, however, the slope of the bottom face of the overhang varies only because of the vertical curvature of the roadway surface and the camber and dead load deflection of the exterior u beam, thereby creating a more pleasing appearance.
county: any design: brg date: 9/2007 hwy: any ck dsn: brg date: 9/2007. slab design example. design: using aashto lrfd bridge design specifications - 4th ed. and txdot lrfd bridge design manual 8' slab with std. reinf. 9'-0' beam spacing, 3'-0' overhang.
lrfd bridge deck design deck overhang the deck overhang design requires checking three cases lrfd a13.4, in reverse order for the presentation : design case 3: the loads specified in article 3.6.1 that occupy the overhang for the load combination strength i limit state;
maximum overhang is 3.33 ft. beyond the design section for negative moment specified in article .6, but not more than 1.3 times the girder depth. minimum overhang is 0.5 ft. from top beam or flange edge except for spread slab and spread box beams, which have a 0 ft. minimum overhang.
for the extreme limit state, the applied loads for deck overhang design are horizontal and vertical vehicular collision forces. these forces are checked at the inside face of the barrier, the design section for the overhang and the design section for the first bay, as described in 17.6.
special design example determine if a special design is required: 1 r a n d = j c $ a = i l 4 9 l0.44 p0.40 recall additional assumptions to verify since oh > 40% of beam spacing, must perform special design find adjusted loads in table 1 of memo 201701: 5/17/2017 bridge office mndot.gov/bridge 18
design step 2.12 - design for flexure in deck overhang. bridge deck overhangs must be designed to satisfy three different design cases. in the first design case, the overhang must be designed for horizontal transverse and longitudinal vehicular collision forces.
01/19 1 general and technical information safety general and technical information dayton superior bridge deck forming accessories are intended only for use by trained, qualified and experienced workers.
bridges deck, or roadway, is part of the superstru c t u r e, and its height and re l a t i v e inaccessibility chal-lenge a contractor more than a typ-ical roadway would. for work to p r oceed smoothly, contra c t o r s must choose the best type of b r idge deck forming system to meet their job requirements. many bridge span superstru c -
construction loading example design example - steel beam bridge bridge geometry three spp ans 66 86 66 skew = 10 degrees bridge typical section clear roadway = 28-0 beam spacing = 3 8-3 slab = 8 overhang = 1-10 ½ 16 beam details w 36x135 positive moment regions
design example: two-span continuous strht wide-flange beam bridge design example: three-span continuous strht tub-girder bridge design example: three-span continuous curved i-girder beam bridge design example: three-span continuous curved tub-girder bridge these topics and design examples are published separately for ease of use, and available for free download at the nsba and fhwa websites:
impact of overhang construction on girder design 5. report date november 2009; revised may 2010 6. performing organization code 7. author s seongyeong yang, todd helwig, rich klingner, michael engelhardt, and jeremiah fasl 8. performing organization report no. 0-5706 9. performing organization name and address center for transportation research
design example includes detailed design computations for the following bridge features: conc rete deck, steel plate girder, bolted field splice, shear connectors, bearing stiffeners, welded connections, elastomeric bearing, cantilever abutment and
lrfd design examples. prestressed precast concrete beam bridge design. view example in pdf format design example 1 download example as a mathcad workbook zip cast-in-place flat slab bridge design. view example in pdf format design example 2 download example as a mathcad workbook zip adhesive anchor examples.
lrfd design examples. prestressed concrete psc girder superstructure bridge design example - us units pdf version 1.7 mb steel girder superstructure bridge design example - us units pdf version 3.2 mb
figure 2. overhang formwork typically requires brackets for support. here, overhang brackets are spaced to maximize the spanning ability of the joist. figure 3. reusable, adjustable form hangers can help speed the placing and stripping of bridge deck formwork.
deck overhang will be designed for the dead load and live load that occupy the overhang. for design case 3, application of design vehicular live load shall be in accordance with provision .4 of the lrfd specifications .
design step 4 design of deck prestressed concrete bridge design example task order dtfh61-02-t-63032 4-5 future wearing surface: minimum = 0.65 maximum = 1.5 it is not intended to maximize the load effects by applying the maximum load factors to some bays of the deck and the minimum load factors to others.
concrete deck design example. obtain design criteria design step 2.1. commentary for 1: includes: girder spacing, number of girders, top and bottom cover, concrete strength, reinforcing steel strength, concrete density, future wearing surface, concrete parapet properties, applicable load combinations, resistance factors
the office has designed the deck overhang on standard sheets according to the aashto lrfd specifications. because traffic railings are attached to the bridge deck, the designer also should consult the decks article in this manual bdm 5.2 . the intent of the traffic railing and supporting deck design is to make the deck
the minimum deck overhang shall be 10 beyond the edge of the top flange for steel beam/girders and 3 beyond the edge of the top flange for prestressed concrete bulb-t beams. the maximum deck overhang shall be 0.35 x the beam/girder spacing or 4-0, whichever is less.