Parapet/railing terminal walls shall be located on the superstructure.

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1 GENERAL INFORMATION: This section of the chapter establishes the practices and requirements necessary for the design and detailing of deck slab extensions at abutments. For general requirements and guidelines see File Nos thru -5. The details shown in this section are intended only to provide the designer with the necessary detailing practices and requirements for the detailing of deck slab extensions. Concrete deck slab main and distribution reinforcement shall be detailed and placed in accordance with the requirements set forth in Chapter 10 except where otherwise noted in this section. Deck slab extensions shall be designed to resist the loads and forces to which the bridge deck system may be subjected. ES series bars shown in the details contained in this section shall be of the size and spacing required when combined with the deck slab distribution reinforcement (SL series bars), the deck slab extension will have sufficient strength to resist these loads and forces. Deflection of deck slab extension plus live load deflection of bearing assembly shall be limited to no more than one-half the thickness of the expanded rubber joint filler on top of backwall in order to prevent any upward forces being transmitted into the deck slab extension. Sample design calculations are included in File Nos thru of this section to assist the designer in the design of deck slab extensions. Parapet/railing terminal walls shall be located on the superstructure. The end of slab shall be used as a reference line for the Beginning of bridge and End of bridge shown on the developed section along the centerline or baseline on the title sheet. End of slab shall be labeled on the deck slab plan. The back of backwall/stem shall be used as a construction/layout reference line on the plan view shown on the substructure layout, curved bridge layout, erection diagram the abutment details. Deck slab extension details shall be shown with the Deck Slab Plan, Deck Slab Elevations and Deck Slab Placement Schedule in the bridge plan assembly. Deck slab extension details shall be shown using phantom lines with abutment sections. For location of deck slab extension details in the bridge plan assembly, see File No The design and detailing of abutments for use with deck slab extensions is similar to that for abutments. For design and detailing of abutments, see Chapter 17. Wingwall haunches shall be designed to resist the moment and shear transferred through the rub plates. For details of abutment drains, see Chapter 22. On projects where the deck extension is utilized and an approach slab is required, then a buried approach slab shall be used. For details of buried approach slabs, see Chapter 19. Details of drainage details specific to using a buried approach slab with deck slab extension are included in this section. SHEET 1 of 31 GENERAL INFORMATION FILE NO

2 GENERAL INFORMATION (Continued): The minimum depth of deck slab extension for steel beam/girder superstructures shall be 12. Deck slab extension shall bear uniformly on the top of end diaphragm for design strength. On structure widths up to approximately 48', the designer shall connect the outside depths by a straight line, provided the maximum depth is not exceeded. Examples of deck extension on steel are shown on sheet For structure widths greater than 48', the designer shall slope the backwalls parallel to top of deck maintaining the minimum depth. Designer has some flexibility in determining whether to design straight lined or to design parallel to cross slope. Other considerations in this determination would be the elevations at the outside edges of deck slab. Certain gradients and skews could increase or decrease these numbers and should be checked. The depth and size of diaphragms are additional factors in design. Straight line design provides for easier construction. Less abutment elevations calculations are needed for design. Parallel to cross slope provides for a more uniform design. Lower transverse forces are at the acute haunches. Smaller rub plates and smaller load applied to wing haunch may be additional considerations. The depth of deck slab extension shall not exceed 1-8. Bottom of deck slab extension and top of abutment backwall shall be sloped parallel to finished grade of deck slab while maintaining the minimum depth of 12. See transverse sections on sheet The deck slab extends pass the back of backwall by four (4) inches. This dimension is affected by the thermal movement of the superstructure. The four (4) inches shall be set so that at 60 F it is at the midpoint of its movement. For design/detailing check list for deck slab extensions, see File No SHEET 2 of 31 GENERAL INFORMATION FILE NO

3 Section on top of diaphragm near outside member. Section shown at interior with straight line when deck slab depth less than diaphragm depth. Section shown at maximum thickness with straight line with slab depth less than diaphragm depth.. SHEET 3 of 31 GENERAL INFORMATION FILE NO

4 CROWNED DECK SLAB For use up to approximately 48 width CROWNED DECK SLAB For use when straight-line exceeds 1-8 depth SUPERELEVATED DECK SLAB TRANSVERSE SECTIONS SHEET 4 of 31 GENERAL INFORMATION FILE NO

5 SAMPLE DESIGN CALCULATIONS: Given: W Bridge = ft Bridge width out-to-out W = ft Bridge width curb-to-curb clear L = 250 ft Total bridge length (2 span continuous steel plate girder) bridge L = 125 Span length at the abutment to be designed Span L = 125 ft Thermal movement length at the abutment to be designed thermal S = ft Spacing of beams/girders (not along skew) beam Overhang = ft N b = 5 CS = θ = 30 Overhang Number of beams/girders Cross slope Skew angle Soil, concrete, and steel properties: γ soil = 145 pcf K P = 12 Unit weight of soil (use 145 for structural backfill) Passive earth pressure coefficient w = 150 pcf Unit weight of concrete Conc SHEET 5 of 31 SAMPLE DESIGN CALCULATIONS FILE NO

6 f = 4,000 psi Compressive strength of superstructure concrete csuper f = 3,000 psi Compressive strength of substructure concrete csub E = 33(w c E csuper conc ) 1.5 ' c f = 3,834,000 psi Modulus of elasticity of concrete in superstructure E = 3,321,000 psi Modulus of elasticity of concrete in substructure csub E s = 29,000,000 psi f y = 60,000 psi Modulus of elasticity of steel Minimum yield strength of reinforcing steel n = 8 Modular ratio of superstructure super n = 9 Modular ratio of substructure sub F = 2,000 psi g Maximum galling stress for ASTM A276 Type 316 steel, of which the rub plates are constructed. Δ = 60 Temperature range for expansion texp Δ = 60 Temperature range for contraction tcont Δ = 120 t Total temperature range for expansion/contraction α = 6.5x10-6 per º F Coefficient of linear expansion for steel Determine depth of deck extension: Slab thickness = 8.5 in. Bolster thickness over support = 1.5 in. Top flange thickness at support = 0.75 in. Distance from bottom of top flange to top of end diaphragm = 3.0 in. Depth top of slab to top of end diaphragm/channel at exterior girder = 8.5 in in in = in. Cross-slope times overhang = 3.0 ft (¼ in. per foot) = 0.75 in. Exterior edge of deck slab thickness = in in. = 13.0 in. Determine whether to design parallel to cross-slope or straight-line from exterior to exterior edge of deck slab. Cross-slope times distance from centerline to exterior deck = ft (¼ in. per foot) = 5.42 in. Add to exterior edge of deck slab to get centerline depth = 13.0 in in = in. SHEET 6 of 31 SAMPLE DESIGN CALCULATIONS FILE NO

7 Summary For the example problem, assume that no additional considerations affect the design. The minimum and maximum depth requirements for deck slab extension with crown deck utilizing straight-line from exterior to exterior are met. Exterior depth of deck = 13.0 > 12.0 OK Depth of deck at exterior diaphragm = Centerline depth of deck = < 20.0 OK > 12.0 OK If design is parallel to cross-slope, the design depth is to top of diaphragm. Design depth would be If straight-line method is utilized, the design depth is limited to the exterior depth of deck due to the cross-slope of the deck. For ease of fabrication, use straight-line method with a design depth of 13.0 Cover = 3.5 Distance to centerline of reinforcement d = = 9.50 in. TRANSVERSE SECTION SAMPLE DESIGN CALCULATIONS FILE NO SHEET 7 of 31

8 Determine cantilever arm for moment and deflection design: SLAB END DETAIL Overhang = 4.0 in Backwall thickness = 12.0 in To CL bearing = 12.0 in Total = = 28.0 in = 2.33 ft Lever arm = 28/cos θ = 28/cos 30 = in = 2.69 ft Determine area of reinforcement required: Moment and shear due to dead load weight of the deck slab extension: h avg = ( ) (½) = in = 1.31 ft W DL = 150 lbs/ft 3 (1.31 ft) = 196 lbs per square foot of slab lbs ( 2.69 ft) w L 2 2 M ft DL = = = ft-lbs per foot of slab 2 2 lbs V DL = w x L = 196 (2.69 ft) = lbs per foot of slab ft 2 SHEET 8 of 31 SAMPLE DESIGN CALCULATIONS FILE NO

9 Moment and shear due to wheel load on deck slab extension: For computing bending moment in foot pounds per foot for longitudinally reinforced slabs shall by: M w = P (S) E (ft-lbs per foot of slab) where P = 16,000 lbs (wheel load for HS20 loading) Conservatively, E is set to equal 4.0 feet. S = distance in feet from load to point of support (face of diaphragm) = 2.33ft / cos 30 = 2.69 ft ( ) = P S 16,000 lbs 2.69 ft M w = = 10,776 ft-lbs per foot of slab E 4.0 Assume live load impact fraction equal to 30% M w+i V w+i = 1.30(10,776 ft-lbs) = 14,010 ft-lbs per foot of slab = 1.30(16,000 lbs)/4.0 ft = 5,200 lbs per foot of slab Moment due to passive earth pressure: lbs ft ( 12)( ft) 2 q p = γ s Kp h = = 1,492 lbs per foot of slab 2 e = in in 3 = 2.62 in. ( 2.62 in) 1,492 lbs M p = q p e = = 326 ft-lbs per foot of slab in 12 ft SHEET 9 of 31 SAMPLE DESIGN CALCULATIONS FILE NO

10 The moment due to passive pressure induces additional deflection which can be converted to an effective P load, P. pvertical P pvertical = Mp/Lever Arm = 326 ft-lbs/2.69 ft = 121 lbs per foot of slab Total moment capacity required of the deck slab extension: M total = M DL + M w+i + M p = 713 ft-lbs + 14,010 ft-lbs ft-lbs = 15,049 ft-lbs per foot of slab P Total = P DL + P w + P PVeritcal = 529 lbs + 5,200 lbs lbs = = 5,850 lbs per foot of slab Area of additional reinforcement required: A s (provided by top distribution steel) = 0.19 in 2 per foot of slab A s (provided by bottom distribution steel) = 0.19 in 2 per foot of slab Using the Bridge Concrete Section Analysis Program (trial and error) or alternative method, the total area of top reinforcement required, A (total required) = 0.88 in 2 per foot of slab. s 2 A s (additional required) = 0.88 in (total required) 0.19 in 2 (provided) 2 = 0.69 in per foot of slab 2 provided = 0.70 in per foot of slab). Therefore use #6 bars (ES 7.5 o/c max. (A s Maximum reinforcement size is limited to #6 bar size. Spacing shall not be less than four (4) inches. Check deflection of section: Δ Load 3 PTotal L = 3 Ec I where P Total = P DL + P w + P PVeritcal = 5,850 lbs L = in (overhang length) E c = 3,834,000 psi I = moment of inertia SAMPLE DESIGN CALCULATIONS FILE NO SHEET 10 of 31

11 For computing the moment of inertia for use in computation of deflections, Article of the AASHTO specifications gives the following equation: Ie 3 3 M cr M I 1 cr = g + I cr I AASHTO Eq. 8-1 M M g a a f 7.5 f ' r = c = 7.5 4,000 psi = 474 psi ( 13.0 in) 3 3 b h 12 in I g = = = 2,197 in f 474 psi 2,197 in 4 r Ig in M cr = = / 12 = 13,361 ft-lbs yt in ft M a = M w = 15,049 ft-lbs I cr = moment of inertia of cracked section transformed to concrete = 407 in 4 (Bridge Concrete Section Analysis Program) or alternative method ,361 ft - lbs 4 13,361 ft - lbs + 4 I e = 2,197 in 1 = 474 in 1,669 in 4 15,049 ft - lbs 15,049 ft - lbs I e < I g = 2,197 in 4 Therefore, I = 1,660 in 4 Δ Load = in in 5,850 lbs ft x 12 ft = 3 3,834,000 psi 4 ( )( 1,660 in ) 3 Conservatively, the cracked moment of inertia, 407 in 4 could be used in the above equation. The resulting deflection is in. Deflection in bearing: The deflection of the bearing is also affected by the deflection of the live load applied. The compressive deflection and long term creep deflection shall be considered. The deflection of the cantilever is limited to one-half the thickness of the expanded rubber joint filler to prevent any significant upward forces to the deck extension. If the there is more than 0.25 inch deflection than the expanded rubber joint filler may be increase to 3 / 4 thickness. Steel = 0.0 inches Laminated bearings = Live load deflection in bearings SHEET 11 of 31 SAMPLE DESIGN CALCULATIONS FILE NO

12 Assume steel bearing for this design: Δ bearing = 0.0 Δ Total = = in < 1 / 2 thickness of expanded rubber joint filler OK Distribution reinforcement for deck slab extension, main reinforcement parallel to loading. AASHTO Percentage = Maximum = 50% S Eq Percentage = 100 = 61% > 50% Use 50%. 2 Transverse distribution reinforcing steel in deck extension required is 0.50 (0.845 in ) = 0.42 in 2. Deck has SB/SC05 series at 5.5 inches on center thus area of steel is 0.68 in 2 which is greater than the in 2 needed. No additional steel needed for distribution. Use ET04 in the bottom of deck slab extension. Passive Pressure, Force, and Buttress Force Compute reaction, R p, required to resist the passive soil pressure. See the lateral force derivations for semi-integrals File No Referring to the derivation of lateral force equations, the following equation needs to be solved. R p = q W tan θ ) W 1 + ( tan θ ) L q = 1,491 plf Resultant of passive force at a point along the backwall W = ft Bridge width out-to-out Bridge θ = 30 Skew angle L = 250 ft Total bridge length (2 span continuous steel plate girder) Bridge SHEET 12 of 31 SAMPLE DESIGN CALCULATIONS FILE NO

13 R p = 1,491plf(43.333ft)tan(30) tan(30) 250 = 33,904 lbs The rub plates and wing haunch on the acute corners need to be designed to resist 33,904 lbs. If abutments are not identical, the loading could be different for each abutment. Required Rub Plate Size: Assume allowable galling stress, f g = 0.55F g, = 0.55(2,000 psi) = 1,100 psi Minimum plate size is 8 in x 6 in. x ½ in thick. Maximum height of plate, H max = slab exterior thickness 3 in = 13.0 in 3.0 in = 10.0 in Try 8 x 6 plate first. Rp W min = = h(fg ) 33,904 lbs 6 in ( 1,100 psi) = 5.14 in Thermal movement (expansion/contraction): Thermal movement length shall be based on the two-thirds the total movement for 120 degrees temperature range. Rub plate size shall be sized for this movement length. 2 in Δ L = α Δt L = per F ( 120 F) 125 ft 12 = 0.78 in thermal 3 ft W required = W min + Δ L = 5.14 in in = 5.92 in. Therefore, use 8 in, the minimum. See File No for rub plate guidelines. SHEET 13 of 31 SAMPLE DESIGN CALCULATIONS FILE NO

14 Center the rub plates on edge of deck extension and wing haunch. Opposite corner takes all the expansion and the joint width may need to be increased to satisfy the transverse expansion of the superstructure. SAMPLE DESIGN CALCULATIONS FILE NO SHEET 14 of 31

15 Design of wing haunch: Extend wing haunch perpendicular to edge of deck slab sufficiently to handle R P equal to 33,904 lbs. Width of haunch design is inches, Thus b = in. Determine allowable shear stress carried by concrete in the wing haunch. ' v c = 0.95 fc = ,000 psi = 52.0 psi Determine required d for concrete only to carry the applied load with 125% overstress allowed for Group IV loading. R v = P bd(1.25) Solving for d d = Rp bv (1.25) c 33,904lbs = = in in(52 psi)(1.25) Haunch depth required without stirrups, h, would be in in = in. Section can be reduced with the use of stirrups to minimize the space required and the amount of concrete needed. SAMPLE DESIGN CALCULATIONS FILE NO SHEET 15 of 31

16 Try a depth of haunch of 24.0 inches. This yields an approximate d = 24.0 in. 3.0 in. = 21.0 in. Additional d value could be used if the sloped portion of the wing is considered in providing additional resistance in the case of elephant ear wings. However, it shall be ignored in this example. v = R P bd(1.25) = 33,904 lbs in( 21 in)1.25 = 93.1 psi v = v C+ vs Solving for v S v S = = 41.1 psi Therefore, stirrups required. Shear reinforcement required by AASHTO is given by v sbs A V = AASHTO Eq. (8-7) fs A f Solving for s = v s v sb. Try #4 stirrups, A V = 0.4 sq. in. s = (0.4 in )(24,000psi) 41.1psi( in) = inches per AASHTO Eq. (8-7) and #4 reinforcing steel. AASHTO requires that when v - v C exceeds Article 8.19 shall be reduced by one-half. 2 ' f c the maximum spacing given in ' v - v C = 41.1 psi < 2 f c = psi AASHTO does not apply. Minimum shear reinforcement required by AASHTO is given by 50b ws A V = fy AASHTO Eq. (8-64) SAMPLE DESIGN CALCULATIONS FILE NO SHEET 16 of 31

17 Solving for s = A v f 50b y w s min = (0.4 sq. in.)(60,000psi) = inches 50(13.875in.) AASHTO (minimum). s max = 24.0 inches AASHTO s max = 21.0/2 = d/2 = 10.5 inches AASHTO Therefore, use #4 reinforcing stirrups at 10½ inches in wing haunch as a minimum. Determine moment in wing haunch. h = inches Lever arm, y = h/2 = /2 = 7.0 inches Group IV loading allows for 125% overstress. Reduce load, R P by 1.25 R P = 33,904 lbs. /1.25 = 27,200 lbs (rounded up to nearest 100). MHaunch = y R p = 189,865 in-lb = 15,822 ft-lb Area of additional reinforcement required: Using the Bridge Concrete Section Analysis Program (trial and error) or alternative method, the total area of reinforcement required, A s (total required) = 0.40 in 2 for the wing haunch. SHEET 17 of 31 SAMPLE DESIGN CALCULATIONS FILE NO

18 Check minimum reinforcement per AASHTO h fc 24 3,000 min ρ s = 1.7 = 1.7 = d fy 21 60,000 A sc = ρ s (bd) = (13.88 )(21 ) = 0.59 in 2. Try 3 - #4 A s < A sc, then check 4 / 3 A s = 0.53 in 2 < A sc, then use 4 / 3 A s. 2 A s provided = 0.60 in > 0.59 in 2 OK Locate the reinforcing steel at an effective d of 21.0 inches from the applied point of load. Note: The above sample design calculations is for a two span continuous steel plate girder bridge. Design procedure is similar for a prestressed concrete beam bridge. SHEET 18 of 31 SAMPLE DESIGN CALCULATIONS FILE NO

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22 CHECK LIST FOR 1 Wing haunch at acute corner shall be designed to resist the moment and shear induced by the force resulting from the passive earth pressure and the skew. Rub plates are only required at the acute corners of skewed bridges. Rub plates to be centered vertically and horizontally over contact area. 2 Minimum thickness of the preformed joint filler between the backwall and the wing at the obtuse corner shall be 1. This may be increased due to thermal expansion in the transverse direction. 3 Extend wing 6 above finished grade. Not required for bridges without skew or where terminal wall is on the substructure. 4 Top of rub plate to begin 1 1 / 2 below top of deck. Bottom of rub plate to maintain 1 1 / 2 clear from bottom of deck extension. Preformed joint filler to extend as shown. 5 Delete this note if railings are used or slip forming of parapets is not allowed. 6 Show plan and elevation view of deck slab extensions at a preferred scale of 3 / 8 = 1-0. The elevation view should be projected down from the plan view. When bridge is not on skew and where sufficient room is available in elevation view, plan view is not required. 7 Label the location centerline/baseline as shown on the title sheet. 8 End of slab shall be used as the reference line for layout of deck slab extensions. 9 Label skew angle (if applicable). 10 The minimum width of backwall shall be 1-0 for bridges without approach slabs and 1-7 for bridges with approach slabs. If approach slabs are a future possibility, the minimum width of backwall shall be The approach slab seat (7 ) shall be provided on all deck slab extensions where future possibility may require the addition of an approach slab. 12 Show sections taken through the deck slab extension at a preferred scale of 3 / 4 = 1-0. Coordinate the sections to provide the necessary details with repetition only where required. 13 Maximum spacing is For instructions on completing the title block, see File No For instructions on completing the project block, see File No For instructions on developing the CADD sheet number, see File Nos and For general sheet order, see File No SLAB END DETAILS SHEET 22 of 31 CHECK LIST FILE NO

23 SLAB END DETAIL The above detail shall be used where a deck extension on steel members is deemed appropriate. 1. Section is taken normal to the abutment face. Section is for slab details and shall be shown on the deck slab details sheets. Substructure details shall be shown on the abutment sheets. 2. The ½ expanded rubber joint filler shall extend the full length of the deck slab extension. 3. This dimension shall be determined by the designer and shown on the plans. 4. Provide dimension as necessary to maintain a 4 minimum overhang throughout the full range of thermal movement. INTEGRAL /JOINTLESS BRIDGES DATE: 11May SLAB END DETAIL SHEET 23 of 31 STEEL MEMBERS - NO APPROACH SLAB FILE NO

24 SLAB END DETAIL The above detail shall be used where a deck extension on prestressed concrete members is deemed appropriate. 1. Section is taken normal to the abutment face. Section is for slab details and shall be shown on the deck slab details sheets. Substructure details shall be shown on the abutment sheets. 2. The ½ expanded rubber joint filler shall extend the full length of the deck slab extension. 3. This dimension shall be determined by the designer and shown on the plans. 4. Provide dimension as necessary to maintain a 4 minimum overhang throughout the full range of thermal movement. INTEGRAL /JOINTLESS BRIDGES DATE: 11May SLAB END DETAIL SHEET 24 of 31 PRESTRESSED MEMBERS - NO APPROACH SLAB FILE NO

25 SLAB END DETAIL The above detail shall be used where an approach slab and deck extension on steel members are deemed appropriate. For details for drainage system, see sheet Section is taken normal to the abutment face. Section is for slab details and shall be shown on the deck slab details sheets. Substructure details shall be shown on the abutment sheets. 2. The ½ expanded rubber joint filler shall extend the full length of the deck slab extension. 3. This dimension shall be determined by the designer and shown on the plans. 4. Provide dimension as necessary to maintain a 4 minimum overhang throughout the full range of thermal movement. DATE: 11May SLAB END DETAIL SHEET 25 of 31 STEEL MEMBERS WITH APPROACH SLAB FILE NO

26 SLAB END DETAIL The above detail shall be used where an approach slab and deck extension on prestressed concrete members are deemed appropriate. For details for drainage system, see sheet Section is taken normal to the abutment face. Section is for slab details and shall be shown on the deck slab details sheets. Substructure details shall be shown on the abutment sheets. 2. The ½ expanded rubber joint filler shall extend for the full length of the deck slab extension. 3. This dimension shall be determined by the designer and shown on the plans. 4. Provide dimension as necessary to maintain a 4 minimum overhang throughout the full range of thermal movement. DATE: 11May SLAB END DETAIL SHEET 26 of 31 PRESTRESSED WITH APPROACH SLAB FILE NO

27 RUB PLATE DETAIL 4 plates required - 2 at each acute corner Bridges on skews shall be provided with rub plates on the deck slab extensions. Rub plates are not required for bridges with skew = 0. The stainless steel plate shown above shall conform to the requirements of ASTM 276, Type 316. Rub plates shall be designed to resist horizontal forces due to thermal induce passive earth pressures and to accommodate the travel due to thermal movements. For sample design calculations, see File Nos and -18. Minimum size of rub plates shall be 8 (W) x 6 (H) x 1 / 2. H max = depth of deck slab extension 3 (1 1 / 2 concrete cover top and bottom of plate). Spacing of shear studs shall not exceed 6. Rub plates shall be centered vertically on the depth of the deck slab extension and horizontally on the contact area of the deck slab extension and the wingwall haunch. Add appropriate note on the plan sheet for estimated quantities for cost of rub plates. For steel beams/girders, include cost in structural steel. For concrete beams, include cost in abutment concrete (Class A3). DATE: 11May2007 SHEET 27 of 31 RUB PLATE FILE NO

28 Terminal wall for deck extension shall be extended beyond the end of slab as shown above. For example partial details of terminal wall. See File No For details of drainage, see File No and -31. Note to designer: Terminal walls for parapet/railings shall extend 2'-3" beyond the end of slab extension and shall be deepened to the depth of the deck slab extension as shown. The deepened section assists in limiting the amount of erosion at the end of the deck slab. Remaining details shall be as shown on the parapet/railing system utilized. DATE: 11May2007 SHEET 28 of 31 TERMINAL WALL FILE NO

29 ELEVATION VIEW PART PLAN TYPICAL FOR SKEWED CROSSING PART PLAN TYPICAL FOR STRAIGHT CROSSING DATE: 11May2007 SHEET 29 of 31 TERMINAL WALL FILE NO

30 Note to Designer: TERMINAL WALL, BURIED APPROACH SLAB, AND PIPE UNDERDRAIN RELATIONSHIP DETAIL 1. Dimension shall be three feet beyond edge of pavement as a minimum. The approach slab shall be kept one foot from face of rail. PIPE UNDERDRAIN END DETAIL SHEET 30 of 31 ABUTMENT DRAIN DETAILS FILE NO

31 PIPE UNDERDRAIN NOTES TO BE PLACED ON PLANS (To be used only when buried approach slab is used) Pipe underdrain shall conform to the requirements of Section 232. The pipe underdrain shall follow the cross slope of the roadway over the approach slab. The pipe underdrain shall extend to 12" past the edge of the side slope and be located to provide free drainage away from the structure. The slope towards the side slopes shall be no less than two percent (2%). Porous backfill shall be placed around the pipe underdrain as detailed and as directed by the Engineer. The porous backfill shall extend 12 inches off the end of the deck extension over the buried approach slab and then 18" off the end of deck extension to the outside edge of wings. The porous backfill shall be paid for as Porous Backfill when it is a bid item and when porous backfill is not a bid item it shall be included in the bid price for the buried approach slab. The bid price shall be full compensation for all labor, tools, materials, equipment, and incidentals required for the satisfactory completion of the work. When a bid item, pipe underdrain will be measured in linear feet, complete-in-place and will be paid for at the contract unit price per linear feet. When not a bid item, pipe underdrain shall be included in the bid price for the buried approach slab. SHEET 31 of 31 ABUTMENT DRAIN DETAILS FILE NO