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AASHTO- Load and Resistance Factor Design (LRFD)
Railings
V 1.2 – Rev. 1.17.08
Credits
The content for this class has been provided by the following PB employees:
Paul Pilarski, P.E., S.E.
Emily Elwood, E.I.T.
Ali Askari, E.I.T.
If you have any questions about the content of this course please contact Paul Pilarski. If you have any technical difficulties, please contact your IT Help Desk.
Download Information
• As with all of our LRFD courses, you may download a PDF version of this course for your future reference.
• Click on the ATTACHMENTS link located in the upper right corner of this course window to access the document and save the file to your desktop.
Successful Completion
• After completing the content within the class you will be asked to take a final test to ensure that you mastered the key training objectives.
• You will need to make a minimum scoreof 80% to receive credit for passing the class.
• Successful completion of the class will earn 0.1 IACET CEU.
• Please refer to your state’s specific continuing education requirements regarding applicability.
Curriculum
This class is the final class in the Structures TRC curriculum for LRFD Design, developed internally at PB. The LRFD Specifications introduce a new section that specifically addresses railings.
• Foundations
• Deck & Deck Systems
• Joints and Bearings
• Abutments, Piers, and Walls
• Railings
• Introduction to LRFD
• Loads and Load Factors
• Concrete Structures
• Steel Structures
• Buried Structures
Objectives
At the end of this course you should be able to identify:
1. The variety of railing types that exist2. Common design issues with railings3. The LRFD Test Level railing categories and applications4. Applications of yield line theory to concrete railing design
5. Examples of LRFD loading applications to common pedestrian and traffic railing designs
This course will take you approximately one hour to complete.
Course Outline – LRFD Railings
Course Outline
1. Railing Types and Considerations
2. Traffic Railings
3. Railing Design Example
4. Pedestrian/Bicycle Railings
5. Combination Railings
Topic 1
Topic 1Railing Types and Considerations
Topic 1- Railing Types and Considerations
Railing Selection
• Applicable railing design/retrofit:• All new bridges
• Bridge Widening Projects
• Deck Replacements
• Railing reconstruction with design speeds in excess of 45 mph
• General factors/considerations:• Variations in traffic volume, speed, vehicle mix, roadway alignment, activities and
conditions beneath the structure (C13.7.1.1)
• Traffic on structure, vehicular (highway), pedestrian
• Ultimate strength, durability, ductility, maintenance, ease of replacement, and long term behavior (C13.5)
• Average Daily Traffic (ADT), Average Daily Truck Traffic (ADTT), Design Hourly Volume (DHV)
Topic 1- Railing Types and Considerations
LRFD Railing Types (Chapter 13)
• Traffic Railing (Art. 13.7)
• Pedestrian Railing (Art. 13.8)
• Bicycle Railings (Art. 13.9)
• Combination Railings (Art 13.10)
Topic 1- Railing Types and Considerations
Rail Application Guidelines C13.4
• Highway traffic only – Traffic Railing
• Highway traffic and pedestrians: low-speed highways (≤ 45mph) – Combination Railing, Barrier Curb Application
• Highway traffic and pedestrians: high-speed highways (> 45mph) – Combination Railing, Outboard & Inboard Application
• Pedestrians only – Pedestrian/Bicycle Rail
Topic 1- Railing Types and Considerations
Common Materials
• Steel
• Aluminum
• Concrete
• Timber
See Commentary Section C13.5
Topic 1- Railing Types and Considerations
Railing Selection
• Standard• Availability
• Cost
• Non-Standard• Increased Fabrication
• Increased Design Review
• Possible crash testing required
• Funding• TH Projects
• SA Projects
Topic 1- Railing Types and Considerations
Maintenance Issues
• Snow plow
• Galvanizing and painting• Galvanize for protection
• Paint for aesthetics
Rub Rail
Topic 1 – Railing Types and Considerations
LRFD Limit States and Resistance Factors
• Applicable load combinations: Table 3.4.1-1
• Resistance factors specified in Articles 5.5.4, 6.5.4, 7.5.4, and 8.5.2
• Strength Limit State – Pedestrian and Bicycle Railings
• Loads (LL) given in Section 13
• Extreme Event Limit State – Traffic Railings
• Impact forces (CT), as described in 3.6.5
• Section 3.6.5 outlines need for impact protection
• Loads given in Section 13 Appendix A
Course Outline – LRFD Railings
Course Outline
1. Railing Types and Considerations
2. Traffic Railings
3. Railing Design Example
4. Pedestrian/Bicycle Railings
5. Combination Railings
Topic 2
Topic 2
Traffic Railings
Topic 2 - Traffic Railings
Traffic Railing (Art. 13.7.1.1)
Consideration should be given to:
• Protection of the occupants of a vehicle in collision with the railing
• Protection of other vehicles near the collision
• Protection of persons and property on roadways and other areas underneath the structure
• Possible future rail upgrading
• Railing cost-effectiveness
• Appearance and freedom of view from passing vehicles
Topic 2 – Traffic Railings
Traffic Railing (13.7.2)
Test Level Index
Test Level
Application Test Speed
Vehicle Characteristics
TL-1 •Work zones, low posted speeds, low volume
•Low speed local streets
30 mph30 mph
Small Auto (1550 lbs, 1800 lbs)Pickup Truck (4500 lbs)
TL-2 •Work zones
•Local and collector roads, small number of heavy vehicles, reduced posted speeds
45 mph45 mph
Small Auto (1550 lbs, 1800 lbs)Pickup Truck (4500 lbs)
TL-3 •Wide range of high-speed arterial highways, low mixtures of heavy vehicles
•Favorable site conditions
60 mph60 mph
Small Auto (1550 lbs, 1800 lbs)Pickup Truck (4500 lbs)
Topic 2 – Traffic Railings
Traffic Railing (13.7.2)
Test Level Index (Cont.)
Test Level
Application Test Speed
Vehicle Characteristics
TL-4 •High speed highways, freeways, expressways and Interstate highways
•Mixture of trucks and heavy vehicles
60 mph60 mph50 mph
Small Auto (1550 lbs, 1800 lbs)Pickup Truck (4500 lbs)Single-Unit Truck (18,000 lbs)
TL-5 •Same applications as TL-4, large average daily truck traffic, unfavorable site conditions
60 mph60 mph50 mph
Small Auto (1550 lbs, 1800 lbs)Pickup Truck (4500 lbs)Tractor Trailer (80,000 lbs)
TL-6 •Tanker-type trucks or similar high center of gravity vehicles
•Unfavorable site conditions
60 mph60 mph50 mph
Small Auto (1550 lbs, 1800 lbs)Pickup Truck (4500 lbs)Tractor-Tanker Trailer (80,000 lbs)
Topic 2 – Traffic Railings
Common Traffic Railings:
• W-Beam Bridge Rail
• Thrie-Beam Bridge Rail
• Metal Tube Bridge Rail
• Vertical Concrete Parapet
• F-Shape Concrete Barrier/Single Slope
• Timber Bridge Rail
W-Beam Bridge Rail
Texas T101 Transition Rail• Height: 32”
• Test Level: TL-2
• Utilized in: Federal Lands
Box Beam Rail (W-Beam Backed with Steel Beam)• Height: 27”
• Test Level: TL-2
• Utilized in: Ohio
Thrie-Beam Bridge Rail
Oregon Thrie-Beam Side Mount• Height: 29”
• Test Level: TL-2
• Utilized in: Oregon
Michigan Bridge Railing, Thrie-Beam Retrofit (R4 Type)• Height: 34”
• Test Level: TL-4
• Utilized in: Michigan
Metal Tube Bridge Rail
Illinois 2399 – Type Side Mount (Steel Tube Bridge Rail Attached to Side of Deck)
• Height: 32”
• Test Level: TL-4
• Utilized in: Illinois
Minnesota Combination Bridge Rail, Design #3 (Steel Tube Bridge Rail Attached to Parapet)• Height: 36”
• Test Level: TL-4
• Utilized in: Minnesota
Oregon 2 – Tube Curb Mount (Steel Tube Bridge Rail Attached to Curb)• Height: 32”
• Test Level: TL-2
• Utilized in: Oregon
Metal Tube Bridge Rail
Foothills Parkway Aluminum Bridge Rail (Aluminum Tube Bridge Rail)• Height: 33”
• Test Level: TL-2
• Utilized in: Federal Lands
California Type 18 (Steel Tube Bridge Rail Attached to Side of Deck)• Height: 36”
• Test Level: TL-2
• Utilized in: California
Vertical Concrete Parapet
New Jersey Barrier• Height: 32”
• Test Level: TL-4
• Utilized in: Georgia
Type 732 Concrete Barrier• Height: 32”
• Test Level: TL-4
• Utilized in: California
32”/42” F-Shape• Height: 32”/42”
• Test Level: TL-4
• Utilized in: Florida
F-Shape concrete Barrier/Single Slope & Timber Bridge Rail
Timber Rail 3 Bridge Rail
• Height: 27”
• Test Level: TL-2
Topic 2 – Traffic Railings
Custom or New Traffic Railings:
• Testing required for new systems per LRFD 13.7.3.1.2
• Previously tested railings may be used provided no changes made to the features tested (LRFD 13.7.3.1.1)
• Geometry must meet geometric constraints previously mentioned
• Design according to LRFD 13.7.3 and Appendix A
Topic 2 – Traffic Railings
Minimum Height of Traffic Parapet or Railing (Art 13.7.3.2)
Ref. Table A13.2-1
Test Level Minimum Railing Height, H
TL-1 27.0 in
TL-2 27.0 in
TL-3 27.0 in
TL-4 32.0 in
TL-5 42.0 in
TL-6 90.0 in
Topic 2 - Traffic Railings
Traffic Railing Geometry (A13.1.1)
Figure 1: Typical Traffic Railings
• Distance below bottom rail, cb• Setback distance, S• Maximum opening, c• Minimum Height, H• Rail Height, A• ΣAi > 25% of H
Topic 2 - Traffic Railings
Traffic Railing Geometry (A13.1.1)
Figure 2: Potential for Wheel, Bumper, or Hood Impact with Post
• Vertical clear opening, c
• Post setback, S
Topic 2 - Traffic Railings
Traffic Railing Geometry
Figure 3: Post setback and rail configuration limits
Topic 2 – Traffic Railings
Traffic Rail – Traffic Railing Design Forces (Ref. Article A13.2)
The effective height of the vehicle rollover force, He is:
12.13A.EqnF2WB12GH
te −−=
where:
G = height of vehicle center of gravity above bridge deck, as specified in Table 13.7.2-1 (in)
W = weight of vehicle corresponding to the required test level, as specified in Table 13.7.2-1 (kips)
B = out-to-out wheel spacing on an axle, as specified in Table 13.7.2-1 (ft)
Ft = transverse force corresponding to the required test level as specified in Table A13.2-1 H
e
Topic 2 – Traffic Railings
Traffic Rail – Traffic Railing Design Forces (Ref. Article A13.2)
The effective height of the vehicle rollover force, He is:
12.13A.EqnF2WB12GH
te −−=
LRFD Table 13.7.2-1
Topic 2 – Traffic Railings
Traffic Railing Design Forces
Topic 2 – Traffic Railings
Traffic Railing Design Forces
12H
R)YR(Y
FRR
eii
ti
≥=
≥=
∑
∑
Topic 2 – Traffic Railings
(ft.) rail of heightH(ft.) wallof heightH
(kips) A13.3.1 Articlein specified as wallofcapacity ultimateR(kips) span one over rail ofcapacity ultimateR
:where
)23.3.13A( R
HRHRY
)13.3.13A(RRR
R
W
W
R
WWRR
WR
=
==
=
−+
=
−+=
Traffic Railing Impact Resistance
Course Outline – LRFD Railings
Course Outline
1. Railing Types and Considerations
2. Traffic Railings
3. Railing Design Example
4. Pedestrian/Bicycle Railings
5. Combination Railings
Topic 3Railing Design Example
Topic 3 – Railing Design Example
Design Example: Type F Barrier, TL-4 Barrier
Type F Barrier Design Outline:
Barrier Flexural Resistance
Interior Region
Exterior Region
Shear Capacity Check
Topic 3 – Railing Design Example
LRFD Design Example – Type F Barrier Design
Method described in LRFD Article A13.3.1
Yield Line Theory• Under loading cracks develop
• Increase loads reinforcement begins to yield in area of crack (yield line develops)
• Load resistance shifts to non-yielded sections Cracks migrate and divides element into rigid
regions
• Regions rotate about yield lines and pivot about their axis of rotation
• Work dissipated by hinges in lines = work expended by loads causing displacements
Before Impact
First yield and hinge formation
Additional hinge formation/Yield lines
Topic 3 – Railing Design Example
Topic 3 – Railing Design Example
Typical reinforcement and geometry:• Horizontal reinforcement: eight #4
bars
• Vertical reinforcement: two #5 bars
• anchored in the deck and projects 10” into the rail
• closed stirrup that laps the other #5 bar
• TL-4 minimum height, 32”
Topic 3 – Railing Design Example
Moment resistance components:
• Mb = the flexural capacity of the cap beam (if present)
• Mw = the flexural capacity of the railing about its vertical axis
• Mc = the flexural capacity of the railing about a horizontal axis
Topic 3 – Railing Design Example
Lce = length of the end regions
Lci = length of interior yield line mechanisms
Topic 3 – Railing Design Example
Determine Mb: Type F barrier has no additional beam section at its top.
Mb = 0
Determine Mw:
1,3,5, and 7: yield lines that produce tension on the inside face of the rail
2, 4, 6, and 8: yield line has tension on the outside face of the rail
Topic 3 – Railing Design Example
Mw Interior Region:
in21.0242.0
2a
in42.0340.485.060.020.04
b'f85.0fA
ca
,where
ksi60f)bar4#for(in20.0A
.Art.fRe),StateLimitEventExtremefor(0.1
12.2.3.7.5.Eqn2adfAM
c
ystotal1
y
2s
ysn
==
=∗∗
∗∗==β=
=
=
=ϕ
−⎟⎠⎞
⎜⎝⎛ −ϕ=ϕ
b = height of rail = 34 in.
Topic 3 – Railing Design Example
Mw Interior Region (cont.):
Bar d (in) Lever Arm
d-a/2 (in)
φMni forInside Face
Tension (k-in)
φMno forOutside FaceTension (k-in)
1 7.72 7.51 90.1
2 7.94 7.73 92.8
3 8.88 8.67 104.0
4 9.07 8.86 106.3
5 10.04 9.83 118.0
6 11.93 11.72 140.6
7 10.77 10.56 126.7
8 14.87 14.66 175.9
Totals 438.8 515.6
Topic 3 – Railing Design Example
ft/ftkip18.1583.2
12/6.515HMM
ft/ftkip92.1283.2
12/8.438HMM
nowo
niwi
−=⎟⎠⎞
⎜⎝⎛=⎟
⎠⎞
⎜⎝⎛ ϕ=
−=⎟⎠⎞
⎜⎝⎛=⎟
⎠⎞
⎜⎝⎛ ϕ=
Mw Interior Region (cont.):
For interior rail regions there is one outside tension yield line and two inside tension yield lines. Compute the average Mw:
ft/ftkip7.13 3
18.15192.122
3M1M2M wowi
intw
−=
∗+∗=
∗+∗=
Topic 3 – Railing Design Example
Mw End Region:
BAR Embedded Length (in)
Bar Fraction
Developed
Developed Bar Area As (in2)
1 36 1.00 0.20
3 24.9 1.00 0.20
5 10.9 0.91 0.18
7 2.1 0.18 0.04
Total 0.62
Topic 3 – Railing Design Example
Mw End Region:
BAR Embedded Length (in)
Bar Fraction
Developed
Developed Bar Area As (in2)
1 36 1.00 0.20
3 24.9 1.00 0.20
5 10.9 0.91 0.18
7 2.1 0.18 0.04
Total 0.62in16.0
232.0
2a
in32.0340.485.0
60.062.0b'f85.0
fAca
ksi60fin20.0A
0.12adfAM
c
ystotal1
y
2s
ysn
==
=∗∗
∗==β=
=
=
=ϕ
⎟⎠⎞
⎜⎝⎛ −ϕ=ϕ
Topic 3 – Railing Design Example
BAR Embedded Length (in)
Bar Fraction
Developed
Developed Bar Area As (in2)
d (in) Lever Arm d-a/2 (in)
φMn for Inside Face Tension
(k-in)
1 36 1.00 0.20 7.72 7.56 90.7
3 24.9 1.00 0.20 8.88 8.72 104.6
5 10.9 0.91 0.18 10.04 9.88 106.7
7 2.1 0.18 0.04 10.77 10.61 25.5
Total 0.62 Total 327.5
Capacities φMn for End Region:
Mw is found by averaging the capacity of the rail over the height of the rail:
ft/ftkip6.983.2
12/5.327HMM n
wend −=⎟⎠⎞
⎜⎝⎛=⎟
⎠⎞
⎜⎝⎛ ϕ=
Topic 3 – Railing Design Example
Section for Mc (flexural capacity about horizontal axis) and shear:
Location d (in) Average d (in)
Top 7.97
Mid Top 10.50
Mid Bottom 11.02
Bottom 14.25
12.64
9.24
Topic 3 – Railing Design Example
Mc Interior Region – Bottom Portion :
#5 bar basic hook development length
( )( ) in98.988.117.02.1db ==l
( ) in88.114625.00.38
'fd0.38
c
bhb ==
∗=l
Modification factors
5.2”
4.5”
%97 in98.9
in5.4in2.5developed %
=
+=
Avg. “d” = 12.64”
MnDOT chose to assume 75%
Topic 3 – Railing Design Example
Determine Mc (Bottom Portion):
Bottom Portion
Compression block depth and
moment per foot:
Location d (in) Average d (in)
Top 7.97
Mid Top 10.50
Mid Bottom 11.02
Bottom 14.25
12.64
9.24
Astop = 0.31in2/ft x 75% = 0.23 in2/ft
( )( ) ft/ftkip3.14121
234.064.126023.00.1
2adfAMM
in34.012485.0
6023.0b'f85.0
fAca
botbotysbotncbot
c
ysbot1bot
−=⎟⎠⎞
⎜⎝⎛⎟⎠⎞
⎜⎝⎛ −=
⎟⎠⎞
⎜⎝⎛ −ϕ=ϕ=
=∗∗
∗=
∗∗
∗=β=
Topic 3 – Railing Design Example
Location d (in) Average d (in)
Top 7.97
Mid Top 10.50
Mid Bottom 11.02
Bottom 14.25
12.64
9.24
Determine Mc (Top Portion):
Top Portion
Compression block depth and
moment per foot:
Astop = 0.31in2/ft
( )( )
ft/ftkip0.14 121
246.024.96031.00.1
2a
dfAMM
in46.0120.485.0
60.031.0b'f85.0
fAca
toptopystopnctop
c
ystop1top
−=
⎟⎠⎞
⎜⎝⎛∗⎟
⎠⎞
⎜⎝⎛ −∗=
⎟⎟⎠
⎞⎜⎜⎝
⎛−ϕ=ϕ=
=∗∗
∗==β=
Topic 3 – Railing Design Example
Determine Mc (Average):
( ) ( )
ft/ftkip1.14 ft83.2
ft00.1ft/ftkip3.14ft83.1ft/ftkip0.14M intc
−=
−+−=
Topic 3 – Railing Design Example
Mc End Region:
For the top portion, Astop = 0.62in2/ft
( )( ) ft/ftkip2.27121
291.024.96062.00.1
2a
dfAMM
in91.012485.0
6062.0b'f85.0
fAca
toptopystopnctop
c
ystop1top
−=⎟⎠⎞
⎜⎝⎛⎟⎠⎞
⎜⎝⎛ −=
⎟⎟⎠
⎞⎜⎜⎝
⎛−ϕ=ϕ=
=∗∗
∗=
∗∗
∗=β=
For the bottom portion, Asbot = 0.75(0.62) = 0.47 in2/ft
( )( ) ft/ftkip9.28121
269.064.126047.00.1
2adfAMM
in69.012485.0
6047.0b'f85.0
fAca
botbotysbotncbot
c
ysbot1bot
−=⎟⎠⎞
⎜⎝⎛⎟⎠⎞
⎜⎝⎛ −=
⎟⎠⎞
⎜⎝⎛ −ϕ=ϕ=
=∗∗
∗=
∗∗∗
=β=
( ) ( ) ft/ftkip8.2783.2
00.19.2883.12.27Mcend −=+
=
Topic 3 – Railing Design Example
Summary of Flexural Capacities
Axis Interior Region End RegionMw (Bending about vertical axis)
(Average k-ft/ft)
13.7
14.1
9.6
Mc (Bending about horizontal axis)
(Average k-ft/ft)
27.8
Topic 3 – Railing Design Example
Flexural Capacity Check – Interior Region (Article A13.3.1):
Mbint = 0 Lt = 3.5 ft per Table A13.2-1
Mwint = 13.7 kip-ft/ft
Mcint = 14.1 kip-ft/ft
( )
11.3.13A.Eqnkips0.98HLMM8M8
LL22R
21.3.13A.Eqnft8.9M
HMMH82L
2LL
2ciintc
intwintbtci
wi
intc
intwintb2
ttci
−=⎟⎟⎠
⎞⎜⎜⎝
⎛++⎟⎟
⎠
⎞⎜⎜⎝
⎛−
=
−=⎥⎦
⎤⎢⎣
⎡ ++⎟
⎠⎞
⎜⎝⎛+=
• H = height of wall (ft)
• Lc = critical length of yield line failure pattern (ft)
• Lt = longitudinal length of distribution of impact force Ft (ft)
• Rw = total transverse resistance of the railing
Topic 3 – Railing Design Example
Type F Barrier, TL-4 Barrier• Ft Transverse (kip) = 54
• FL Longitudinal (kip) = 18
• FV Vertical/Down (kip) = 18
• Lt and LL (ft) = 3.5
• He Minimum Height of Horizontal Loads (in) = 32
• H Minimum Height of Rail (in) =32
Topic 3 – Railing Design Example
Flexural Capacity Check – Exterior Region (Article A13.3.1):
Mbend = 0 Lt = 3.5 ft per Table A13.2-1
Mwend = 9.6 kip-ft/ft
Mcend = 27.8 kip-ft/ft
( )
31.3.13A.Eqnkips8.81HLMHMM
LL22R
41.3.13A.Eqnft2.4M
H*MMH2L
2LL
2cecend
wendbendtce
we
cend
wendbend2
ttce
−=⎟⎟⎠
⎞⎜⎜⎝
⎛+∗+⎟⎟
⎠
⎞⎜⎜⎝
⎛−
=
−=⎥⎦
⎤⎢⎣
⎡ ++⎟
⎠⎞
⎜⎝⎛+=
Topic 3 – Railing Design Example
Shear Capacity Check – Exterior Region (Article A13.3.1):
Ft = 54 kips Ref. Table A13.2-1
FL = 18 kips Ref. Table A13.2-1
Shear friction formula:
Use µ = 0.60 and substitute Vres for φVn:
( )[ ]cyvfcvn PfAcAV +µϕ=ϕ
legs7.531.076.1
AA
in76.1ksi6060.090.0
kips9.56f
vA
b
vfreq
2
yv
resvfreq
=⎟⎠⎞
⎜⎝⎛⎟⎟⎠
⎞⎜⎜⎝
⎛
=⎟⎠⎞
⎜⎝⎛
∗∗=⎟
⎟⎠
⎞⎜⎜⎝
⎛
µϕ=
4.8.5f.Rekips9.561854FFV 222L
2tres =+=+=
Topic 3 – Railing Design Example
Shear Capacity Check (continued):
5.7 legs of #5 reinforcement required
Interior Region:
Lci = 9.9 ft
10 provided
Exterior Region:
Lci = 4.2 ft
9 provided
Course Outline – LRFD Railings
Course Outline
1. Railing Types and Considerations
2. Traffic Railings
3. Railing Design Example
4. Pedestrian/Bicycle Railings
5. Combination Railings
Topic 4
Topic 4Pedestrian/Bicycle Railing
Topic 4 – Pedestrian/Bicycle Railing
Pedestrian Railing (Art. 13.8)
Design:
• Minimum height 42.0 in. measured from the top of the walkway
• Max openings – horizontal rails only: • 6” sphere cannot pass through
• Max openings – horizontal and vertical elements (grid):
• 6” sphere cannot pass through lower 27”
• 8” sphere cannot pass through openings above 27”
• Max openings – Rails with fencing• Fence openings < 2.0”
• Suggested that rails should project beyond posts and that a curb should be provided
Topic 4 – Pedestrian/Bicycle Railing
Pedestrian Railing (Art. 13.8)
Design 13.8.2
Railings
• PLL = 0.05 kips/ft
• Horizontally and vertically
Posts
• PLL = 0.20 + 0.050Lwhere L = post spacing (feet)
Chain link fence
• PLL = 0.015 ksf on fence area assuming enclosed
Topic 4 – Pedestrian/Bicycle Railing
Bicycle Railing (Art. 13.9)
Same as pedestrian bridge except:
Geometry
• Railing at 27” spacing or less
• Railing outside of posts to prevent catch hazard
• Rubrails are optional
Design
• Design of rails 54” above surface are left up to the owner/designer
• Railing design load identical to pedestrian railing
Topic 4 – Pedestrian/Bicycle Railing
Pedestrian Railing (Art. 13.8)
Pedestrian railing examples:
Topic 4 – Pedestrian/Bicycle Railing
Bicycle Railing (Art. 13.9)
Bicycle railing examples:
Course Outline – LRFD Railings
Course Outline
1. Railing Types and Considerations
2. Traffic Railings
3. Railing Design Example
4. Pedestrian/Bicycle Railings
5. Combination Railings
Topic 5Combination Railings
Topic 5 – Combination Railings
Combination Railings (Art. 13.10)
High Speed Combination Railing
Low Speed Combination Railing
Topic 5 – Combination Railings
Combination Railings (Art. 13.10)
High-Speed Highways:
• Applicable for design speeds in excess of 45 mph
• Shall conform to pedestrian or bicycle railing requirements (whichever is applicable) Arts. 13.8 and 13.9
• Traffic railing portion: Art. 13.7
• Design loads for pedestrians/bicycles shall not be applied simultaneously with the vehicular impact loads (Ref. Art. 13.10.3)
Topic 5 – Combination Railings
Combination Railings (Art. 13.10)
Low-Speed Highways
• Applicable for design speeds less than 45 mph
• Minimum curb height adjacent to sidewalk is 6 in.
• Shall conform to pedestrian or bicycle railing requirements (whichever is applicable) Arts. 13.8 and 13.9
• Traffic railing portion: Art. 13.7
• Design loads for pedestrians/bicycles shall not be applied simultaneously with the vehicular impact loads (Ref. Art. 13.10.3)
Course Outline – LRFD Railings
Course Outline
1. Railing Types and Considerations
2. Traffic Railings
3. Railing Design Example
4. Pedestrian/Bicycle Railings
5. Combination Railings
Objective Review
You should now be able to identify:
1. The variety of railing types that exist
2. Common design issues with railings
3. The LRFD Test Level railing categories and applications
4. Applications of yield line theory to concrete railing design
5. Examples of LRFD loading applications to common pedestrian and traffic railing designs
References
• American Association of State and Highway Transportation Officials, "AASHTO LRFD Bridge Design Specifications" 4th Edition 2007, Section 13 Railings, Appendix A13 Railings.
• Federal Highway Administration, FHWA California Division, "Bridge Rail Guide 2005". http://www.fhwa.dot.gov/bridge/bridgerail/bridgerail.pdf
• Goodchild, Charles and Kennedy, Gerald, "Practical Yield Line Design". Reinforced Concrete Council, British Cement Association 2003. http://www.concretecentre.com/PDF/PYLD240603a.pdf
• Kettleson, Paul, Railings, Presented at LRFD Bridge Design Workshop, June 12, 2007. Minnesota Department of Transportation Bridge Office. http://dot.state.mn.us/bridge/Manuals/LRFD/June2007Workshop/11a%20Railings.pdf
• Minnesota Department of Transportation, "Mn/DOT Bridge Office LRFD Bridge Design Manual". Minnesota Department of Transportation Manual 5-392, Oakdale, MN, July 2007. Section 13 Railings. http://ihub.dot.state.mn.us/bridge/Manuals/LRFD/LRFD-Manual.pdf
• Western, Kevin, LRFD Railing Design, Presented at LRFD Bridge Design Workshop, 2004. Minnesota Department of Transportation Bridge Office.
Final Assessment
Instructions
You are now ready to begin the final assessment.
• The assessment consists of 10 multiple choice questions.
• You will need to achieve a minimum score of 80% to receive credit for passing the course.
• If you score below 80%, please go back and review the content of this course, and then retake the assessment to achieve a passing score.
When ready, click the Right arrow below to advance to the assessment.
Conclusion
Thank you for completing this course. If you received a passing score on the assessment, simply close this window to exit the course. Your score will be recorded on your transcript. If you did not achieve a passing score, please review the content of this course and thenretake the assessment to achieve a passing score.
You may print a certificate from the My Transcript area of PBUniversity by clicking the cert. icon.
If you need a certificate that specifically states the IACET certification and credit hours, please email a request to us at pbu@pbworld.com.
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