751.12 Protective Barriers

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Contents

751.12.1 Standard Safety Barrier Bridge Curbs

751.12.1.1 Standard Safety Barrier Curbs used in Missouri

Image:751.12 barrier curb - NJ Shape.gif
Type A
Test Level TL-4
Type B
Test Level TL-4
NJ Shape
 
Image:751.12 barrier curb - type c & d.gif
Type C
Test Level TL-5
Type D
Test Level TL-5


Note: For Type F (Temporary Barrier Curb), refer to Missouri Standard Plans 617.20.
  For Thrie Beam Rails, see Widening & Repair information.
  See Structural Project Manager before using Type C or D barriers.

751.12.2 Safety Barrier Bridge Curbs (NJ Shape)

751.12.2.1 General Design

New safety barrier curbs "shall be shown to be structurally and geometrically crashworthy". Therefore, the shape of the safety barrier curb is selected based on crash-tested, or equivalent crash-tested geometry.

The safety barrier curb used on new bridges shall be the 16” New Jersey (MO) safety shape barrier curb which has been crash-tested and FHWA approved as meeting test level TL-4.

Test level TL-4 shall be used for safety barrier curb design. TL-4 is defined by AASHTO as being “generally acceptable for the majority of applications on high-speed highways, freeways, expressways, and interstate highways with a mixture of trucks and heavy vehicles”.


Image:751.12 safety barrier curb dimensions.gif
* Use Rustication on Highway Grade Seperations only
Safety Barrier Curb Dimensions


Material Properties
Concrete  
Unit weight of reinforced concrete, \, \gamma_c = 150 \,lb/ft^3
for modulus of elasticity, \, \gamma_c = 145 \,lb/ft^3
Safety Barrier Curbs  
Safety Barrier Curbs shall consist of:  
Class B-1 Concrete \, f'_c = 4.0 ksi
  \, n = 8
Median Barrier Curbs  
Median Barrier Curbs shall consist of:  
Class B-1 Concrete \, f'_c = 4.0 ksi
  \, n = 8
Reinforcing steel  
Minimum yield strength, \, f_y = 60.0 ksi
Steel modulus of elasticity \, E_s = 29000 ksi

751.12.2.2 Standard Reinforcement Details

Image:751.12 r-bar no wearing surface.gif Image:751.12 r1-bar no wearing surface.gif Image:751.12 r2-bar no wearing surface.gif
R-Bar
Required for Slip Form Option
R1-Bar
Shape 19
R2-Bar
Shape 15
R1 & R2-Bars permissible
only when Slip Forming
not allowed (*)
Image:751.12 16in standard safety barrier curb no wearing surface.gif
16" Safety Barrier Curb
(*) The single R bar adds to the rigidity of the reinforcement during construction and it is believed to help prevent cracking. The single bar also appears to assist maintaining uniform reinforcement cover.


Reinforcement (No Wearing Surface)
Image:751.12 r-bar no wearing surface.gif Image:751.12 16in safety barrier curb no wearing surface.gif Image:751.12 r3-bar no wearing surface.gif Image:751.12 r4-bar no wearing surface.gif
#5-R3
Shape 19
#5-R4
Shape 27 (*)
Image:751.12 r-bar permissible shape no wearing surface.gif
R-Bar 16" Safety Barrier Curb R-Bar Permissible
Alternate Shape (**)
 
Reinforcement (1 3/4" Wearing Surface)
Image:751.12 r-bar 1.75 in wearing surface.gif Image:751.12 16in safety barrier curb 1.75 in wearing surface.gif Image:751.12 r3-bar 1.75 in wearing surface.gif Image:751.12 r4-bar 1.75 in wearing surface.gif
#5-R3
Shape 19
#5-R4
Shape 27
Image:751.12 r-bar permissible shape 1.75 in wearing surface.gif
R-Bar 16" Safety Barrier Curb R-Bar Permissible
Alternate Shape (**)
 
Reinforcement (2 1/4" Wearing Surface)
Image:751.12 r-bar 2.25 in wearing surface.gif Image:751.12 16in safety barrier curb 2.25 in wearing surface.gif Image:751.12 r3-bar 2.25 in wearing surface.gif Image:751.12 r4-bar 2.25 in wearing surface.gif
#5-R3
Shape 19
#5-R4
Shape 27
Image:751.12 r-bar permissible shape 2.25 in wearing surface.gif
R-Bar 16" Safety Barrier Curb R-Bar Permissible
Alternate Shape (**)
(*) Increase leg for latex or low slump concrete wearing surface.
(**) The R3 bar and #5 bottom transverse slab bar in cantilever (P/S panels only) combination may be
furnished as one bar as shown, at the contractor's option.
Note: Use same grade reinforcing steel in Barrier Curb as in slab. Splice length for #5 bars in Barrier Curb = 35".
  Dimensions shown are also typical for structures with latex or low slump concrete (except as indicated).

751.12.2.3 End Bent Reinforcement

Non-Integral End Bents
Image:751.12 non-integral end bent end elevation of barrier curb.gif Image:751.12 non-integral end bent elevation of barrier curb.gif
End Elevation Elevation of Barrier Curb
Image:751.12 non-integral end bent section a-a.gif Image:751.12 non-integral end bent section b-b.gif Image:751.12 non-integral end bent section c-c.gif
Section A-A Section B-B Section C-C
* Spaced with #5-K4 bars.
** Fit bar to follow transition face of curb.


All bars are epoxy coated.
All bars are stirrup bends except for K4, K9, K10 & K11.
Image:751.12 non-integral end bent k1.gif Image:751.12 non-integral end bent k2.gif Image:751.12 non-integral end bent k3.gif Image:751.12 non-integral end bent k4.gif Image:751.12 non-integral end bent k5.gif
#5-K1
Shape 19
#5-K2
Shape 14
#5-K3
Shape 27
#5-K4
Shape 7
#5-K5
Shape 25
Image:751.12 non-integral end bent k6.gif Image:751.12 non-integral end bent k7.gif Image:751.12 non-integral end bent k8.gif Image:751.12 non-integral end bent k9.gif
#5-K6
Shape 25
#5-K7
Shape 25
#5-K8
Shape 25
#5-K9
Shape 20
Image:751.12 non-integral end bent k10.gif Image:751.12 non-integral end bent k11.gif (*) Increase leg for slab
thickness greater than
8 1/2".
#4-K10
Shape 20
#5-K11
Shape 8


Integral End Bents
Image:751.12 integral end bent end elevation of barrier curb.gif Image:751.12 integral end bent elevation of barrier curb.gif
End Elevation Elevation of Barrier Curb
Image:751.12 integral end bent section a-a.gif Image:751.12 integral end bent section b-b.gif Image:751.12 integral end bent section c-c.gif
Section A-A Section B-B Section C-C
* Spaced with #5-K4 bars.
** Fit bar to follow transition face of curb.
*** On skewed structures, if end K3 bar does not meet the Min. 1 1/2" clearance
from front face of diaphragm, a K12 bar may be substituted.


All bars are epoxy coated.
All bars are stirrup bends except for K4, K9, K10 & K11.
Image:751.12 integral end bent k1.gif Image:751.12 integral end bent k2.gif Image:751.12 integral end bent k3.gif Image:751.12 integral end bent k4.gif Image:751.12 integral end bent k5.gif
#5-K1
Shape 19
#5-K2
Shape 14
#5-K3
Shape 27
#5-K4
Shape 7
#5-K5
Shape 25
Image:751.12 integral end bent k6.gif Image:751.12 integral end bent k7.gif Image:751.12 integral end bent k8.gif Image:751.12 integral end bent k9.gif
#5-K6
Shape 25
#5-K7
Shape 25
#5-K8
Shape 25
#5-K9
Shape 20
Image:751.12 integral end bent k10.gif Image:751.12 integral end bent k11.gif Image:751.12 integral end bent k12.gif
#4-K10
Shape 20
#5-K11
Shape 8
#5-K12
Shape 27



Semi-Deep Abutments
Image:751.12 semi-deep abutment elevation of barrier curb.gif
Elevation of Barrier Curb
Image:751.12 semi-deep abutment end elevation of barrier curb.gif Image:751.12 semi-deep abutment section a-a.gif Image:751.12 semi-deep abutment section b-b.gif
End Elevation Section A-A Section B-B
Image:751.12 semi-deep abutment section c-c.gif Image:751.12 semi-deep abutment section d-d.gif * Spaced with #5-K4 bars.
** Fit bar to follow transition face of curb.
Section C-C Section D-D    


All bars are epoxy coated.
All bars are stirrup bends except for K4, K9, K10 & K11.
Image:751.12 semi-deep abutment k1.gif Image:751.12 semi-deep abutment k2.gif Image:751.12 semi-deep abutment k3.gif Image:751.12 semi-deep abutment k4.gif Image:751.12 semi-deep abutment k5.gif
#5-K1
Shape 19
#5-K2
Shape 14
#5-K3
Shape 27
#5-K4
Shape 7
#5-K5
Shape 25
Image:751.12 semi-deep abutment k6.gif Image:751.12 semi-deep abutment k7.gif Image:751.12 semi-deep abutment k8.gif Image:751.12 semi-deep abutment k9.gif
#5-K6
Shape 25
#5-K7
Shape 25
#5-K8
Shape 25
#5-K9
Shape 20
Image:751.12 semi-deep abutment k10.gif Image:751.12 semi-deep abutment k11.gif Image:751.12 semi-deep abutment k12.gif
#4-K10
Shape 20
#5-K11
Shape 8
#5-K12
Shape 27


Continuous Concrete Slab
Image:751.12 cont conc slab end bent end elevation of barrier curb.gif Image:751.12 cont conc slab end bent elevation of barrier curb.gif
End Elevation Elevation of Barrier Curb
Image:751.12 cont conc slab end bent section a-a.gif Image:751.12 cont conc slab end bent section b-b.gif Image:751.12 cont conc slab end bent section c-c.gif
Section A-A Section B-B Section C-C
* Spaced with #5-K4 bars.
** Fit bar to follow transition face of curb.


All bars are epoxy coated.
All bars are stirrup bends except for K4, K9, K10 & K11.
Image:751.12 cont conc slab end bent k1.gif Image:751.12 cont conc slab end bent k2.gif Image:751.12 cont conc slab end bent k3.gif Image:751.12 cont conc slab end bent k4.gif Image:751.12 cont conc slab end bent k5.gif
#5-K1
Shape 19
#5-K2
Shape 14
#5-K3
Shape 27
#5-K4
Shape 7
#5-K5
Shape 27
Image:751.12 cont conc slab end bent k6.gif Image:751.12 cont conc slab end bent k7.gif Image:751.12 cont conc slab end bent k8.gif Image:751.12 cont conc slab end bent k9.gif
#5-K6
Shape 27
#5-K7
Shape 27
#5-K8
Shape 27
#5-K9
Shape 20
Image:751.12 cont conc slab end bent k10.gif Image:751.12 cont conc slab end bent k11.gif  
#4-K10
Shape 20
#5-K11
Shape 8
 
* According to the development length allowed with the slab depth used, bar may or may not be hooked. Development length starts at slab/barrier interface, basic development length for a straight, #5 epoxy coated bar is 18".
** Length varies depending on slab depth. Extend bar to within 1" of construction joint at bottom of slab.
*** Use Shape 11 or create shape as necessary when development length requires hook.

751.12.2.4 Slip-Form Reinforcement Details

Image:751.12 section at end bent (optional slip-form barrier).gif
Section at End Bent (Optional Slip-Form Barrier)
 
Image:751.12 section near joint (optional slip-form barrier).gif
Section Near Joints (Optional Slip-Form Barrier)
 
Image:751.12 optional slip-form barrier section a-a.gif
Section A-A
(*) Each side of Joint Location.

NOTE TO DETAILER:

Optional Slip-Form Safety Barrier Curb details shall be placed on all jobs (except Prestressed Double-Tee Structures) where applicable.

Add #5 cross bracing bars for Slip-Form option. Base the length of these bars on the shortest distance between joints throughout the structure. Show the C-Bars in the Bar List and note that these bars are for the Slip-Form option only.

751.12.2.5 SBC for Wing with Detached Wing Wall

Image:751.12 safety barrier curb on non-integral end bent.gif
SBC on Non-Integral End Bent (*)
 
Image:751.12 safety barrier curb on integral end bent.gif
SBC on Integral End Bent (*)
(*) Detached Wing Wall shown is for illustration purpose only.
  If the detached wing wall has more than one section, see the Structural Project Manager
for possible additional joints in the safety barrier curb (between sections).

751.12.2.6 Guardrail Attachment Detail

Image:751.12 guard rail attachment detail part elevation a-a.gif Image:751.12 guard rail attachment detail part elevation.gif
Part Elevation A-A Part Elevation
  Image:751.12 guard rail attachment detail part plan.gif
  Part Plan
Image:751.12 guard rail attachment detail auxiliary view.gif
Auxiliary View

751.12.2.7 Joint & Rustication Details

Curb Expansion Joints. Openings required for expansion shall be provided in the barrier curb in conjunction with deck joints. For details of expansion joints in barrier curb see expansion device details.

Curb Joints. 1/4 in. joints are located in the barrier curb at locations of negative moments to prevent cracking in the barrier curb. These joints are required when decks are continuous over intermediate bents for both continuous and simple span structures. These joints are also required at the front face of integral end bents. For details of 1/4 in. curb joints at integral end bents see integral end bent details.

Rustication. Rustication shall be used on grade separations only. Rustication shall be terminated four feet from the end of the barrier curb.

Cast-In-Place Barrier Curbs
Image:751.12 joint and rustication details plan of curb joints.gif
   Note: Sawcut between spans shall be offset from centerline of intermediate bent to match any existing offset.
Continuous Structures Part Plan    Continuous Re-Deck of Simple Span Structures Part Plan
 
Image:751.12 joint and rustication details all types of cont structure elevation.gif
Part Section Showing Placement of Joints
*One space = 1/4 Span to nearest 1 in. increment (Span < 40 ft.)
One space = 10 ft. (Span = 40 ft. to 125 ft.)
Two spaces = 10 ft. (Span > 125 ft.)


Optional Slip-Form Barrier Curbs
Image:751.12 joint and rustication details optional slip-form section thru joint and section a-a.gif
Section A-A Section Thru Joint
Image:751.12 joint and rustication details optional slip-form all types of cont structure elevation.gif
Part Section Showing Placement of Joints


Image:751.12 joint and rustication details optional slip-form part plan continuous structures.gif
Note: Sawcut between spans shall be offset from centerline of intermediate bent to match any existing offset.
Continuous Structures Part Plan Continuous Re-Deck of Simple Span Structures Part Plan
Note: Rustication shall be used on grade separations only. Terminate rustication 4 ft. 0 in. from end of wing.


Image:751.12 joint and rustication details part section showing rustication details.gif Note: Rustication to be used on
highway grade separation only.
End rustication 4'-0" from end
of wing.
Part Section Showing Rustication Details  

751.12.2.8 Plastic Waterstop

To eliminate water seepage problems, use a plastic waterstop, as specified, and in accordance with details shown below.

Use a plastic waterstop at all safety barrier curb joints on grade separations, except over railroads and county roads.

Use a plastic waterstop on lower safety barrier curb joint only, for structures with superelevation on grade separations.


Image:751.12 plastic waterstop on bridge filled joint detail.gif
* Rustication to be used on highway grade separations only.
Filled Joint Detail

751.12.2.9 Details of Mounting Light Poles on Safety Barrier Curbs

Part Plan Part Plan
Section A-A Section B-B
Image:751.12 details of mounting light poles bar shape 30.gif Image:751.12 details of mounting light poles bar shape 13.gif Image:751.12 details of mounting light poles bar shape 10.gif
Anchor bolts and nuts shall be in accordance with ASTM A449. Anchor bolts, nuts and washers shall be fully galvanized.
Note to Detailer: Extend slab transverse steel to edge of slab in blister region.
Note: Conduit not shown for clarity.

751.12.2.10 Superelevation Details

Image:751.12 superelevation details-section thru superelevated slab.gif
Section Thru Superelevated Slab


Image:751.12 superelevation details-section thru superelevated approach slab at integral end bent.gif
Section Thru Superelevated Approach Slab at Integral End Bent


Image:751.12 superelevation details-section thru superelevated approach slab at non-integral end bent.gif
Section Thru Superelevated Approach Slab at Non-Integral End Bent
"A" = 2'-8" + (Superelev. Slope x 16")
"B" = 2'-8" - (Superelev. Slope x 16")
"C" = 8 1/2" + (Superelev. Slope x 16")
"D" = 8 1/2" - (Superelev. Slope x 16")


751.12.3 Medians

751.12.3.1 Double Faced Median Barrier Curb (NJ Shape)

Note:Use same grade reinforcing steel in barrier curb as in slab.
 Splice length for #5-R bars in barrier curb = 35".
 Do not use this barrier curb over precast prestressed panels.


Note to detailer:Provide slip-form option for double faced median safety barrier curb. For slip-form option additional #5 cross bracing bars shall be placed on both sides of all joints and R2 bars shall be one bar.


Image:751.12 double-faced median barrier curb reinforcement-r2 bar.gif Image:751.12 double-faced median barrier curb reinforcement-r4 bar.gif
R2 Bar
Shape 15
R4 Bar
Shape 27
Image:751.12 section thru double faced median barreir curb.gif
Section Thru Double Faced Median Barrier Curb
 
Twin Bridge Median Barrier Curb Details
Image:751.12 section thru median curb with open joint.gif
Section Thru Median with Open Joint

751.12.3.2 Concrete Median Curbs

Image:751.12 concrete median curbs-open joint (twin bridges typ).gif
Open Joint (Twin Bridges Typ.)
Image:751.12 concrete median curbs-barrier class (no joint).gif
Barrier Class (No Joint)
Image:751.12 concrete median curbs-mountable class.gif
Mountable Class
Note: All reinforcement shown shall be epoxy coated.
Details shown are very general. Consult Design Layout for specific details for each individual structure.


Concrete Median Curbs (Permissable Alternates)
Bent Bar:
Image:751.12 concrete median curbs (permissalbe alternates)-open joint (twin bridges typ.).gif Image:751.12 concrete median curbs (permissalbe alternates)-barrier class (no joint).gif
Open Joint (Twin Bridges Typ.) Barrier Class (No Joint)
Image:751.12 concrete median curbs (permissalbe alternates)-detail a.gif Image:751.12 concrete median curbs (permissalbe alternates)-detail b.gif
Detail "A" Detail "B"
Image:751.12 concrete median curbs (permissalbe alternates)-field bent bar.gif Add note to plans:
No additional payment will be allowed for the usage of
either alternate anchoring systems.
Resin Anchor:
Image:751.12 concrete median curbs (permissalbe alternates)-resin anchor choice.gif
Note: All reinforcement shown shall be epoxy coated.

751.12.4 Chain Link Fence

Superstructure Near Steps
 
Superstructure at or Near End Panel
 
Image:751.12 pedestrian overpass-superstructure near steps detail a.gif Design Crieria:
Fence fabric weight = 10#/lin. ft.
Eff. wind area = 0.11 area/sq.ft.
Detail "A"  


Image:751.12 pedestrian overpass-landing.gif Image:751.12 pedestrian overpass-section thru fence.gif
Landing Section thru
Fence
 
Details of Handrail Bracket
 
Rail Post Connection (Typical)
 
Plan of Floor Plate
 
Details of Expansion Device Gap
(**) May conflict with any proposed expansion device sidewalk, consult Structural Project Manager.
 
Typical Section Near Splice Gap
Note: 8'-0" max. post spacing for superstructure.

(*) Locate at about 30'-0" centers with at least one splice gap between pull posts.

(Add the following notes to the plans.)
The maximum spacing allowed between pull posts and end posts is 100 ft. Post brace and 1/2ӯ truss rod are required for panels adjacent to pull posts and end posts only.
Connect the lower end of the 1/2"Ø truss rod to the bottom of the pull posts and end posts to which the stretcher bar is attached.


(112") Curved top Pedestrian Fence (Structures)
(Optional fence detail when requested by district or railroad personnel)
Section A-A
 
Curved Top Pedestrian Chain Link Fence
(Galv. Steel) on Sidewalk
NOTE: 8'-0" Max. post spacing for superstructure.

(*) Locate at about 30'-0" centers with at least one splice gap between pull posts.

The maximum spacing allowed between pull posts and end posts is 100 feet. Post brace and 1/2"Ø truss rod are required for panels adjacent to pull posts and end posts only.
Connect the lower end of the 1/2"Ø truss rod to the bottom of the pull posts and end posts to which the stretcher bar is attached.

 
Details at Expansion Device Gap
(**) May conflict with any proposed expansion device sidewalk, consult Structural Project Manager.
 
Typical Section Near Splice Gap
Note: 8'-0" max. post spacing for superstructure.

(*) Locate at about 30'-0" centers with at least one splice gap between pull possts and end posts.

751.12.5 Two Tube Rail (Top Mounted) TL-4 (NCHRP 350)

Guidance

  • Meets TL-4 (NCHRP 350)
  • Typically used on spread box beam bridges.
  • May be used on adjacent box beam bridges where reinforcement is embedded in the beam.
  • Use only in certain applications because of cost.
  • Acceptable for use when roadway width or site distance is a concern.
  • Curb is intrinsic to TL rating and shall be used. Curb shall be used to prevent drainage over deck.
Bridge Standard Drawings - Two Tube Rail (Top Mounted)
(DGN and PDF)
Standard Drawing Guidance may not be available on
Bridge Standard Drawings (PDF) due to formatting.
All Bridge Standard
Drawings (DGN and PDF)
(PDF)
Two Tube Rail Plan and Elevation Details – TTR1
Two Tube Rail Transition Details – TTR2
Two Tube Rail Details – TTR3
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