These plans provide the necessary details to fabricate, construct and install traffic barriers. Note that the use of all Traffic Barrier-TB plans is restricted to WSDOT internal use only. Contact HQ Design for more details.
You will find the following plans for all Traffic Barrier - TB. These plans provide the necessary details to fabricate, construct and install traffic barriers.
You will also find TB – Old Type 1 Barriers. Details and plans are provided for information only. Type 1 guardrails are no longer used by WSDOT for new installations.
This plan is intended to depict a Beam Guardrail Transition system used to transition from Beam Guardrail Type 31 to another structure. This System could be used where there is limited length available and a Standard Transition will not fit. This Transition section consists of an End Section Design F, with a Thrie Beam Rail Section, and Reducer Section Type C.
View Beam Guardrail Transition plan sheet (PDF 745 KB)
This plan provides the necessary details to construct the low speed concrete barrier terminal noted in the WSDOT Design Manual Chapter 1610.
This terminal can be used as an end treatment for Type 2 Concrete Barrier on roadways with a posted speed of 35 mph or less.
These terminals are used infrequently, and concrete products companies willing to do the work inexpensively may be difficult to locate. The initial cost for this terminal might be as high as a manufactured impact attenuator; however, long-term maintenance costs will be significantly less.
View Low Speed Concrete Barrier Terminal plan sheet (PDF 660KB)
This plan depicts the details necessary to provide a Buried Terminal Type 1 (formerly Standard Plan C-4).
Buried Terminal Type 1 previously was an available option for consideration to be used with beam guardrail runs.
For new installations this is no longer an option. It is acceptable to leave a Buried Terminal Type 1 in service for existing situations, if no work is required to the existing barrier run.
View Buried Terminal Type 1 plan sheet (PDF 698KB)
These drawings provide details to construct a Low Profile Barrier. This design may be used for raised medians where the posted speed is 45 mph or less. The barrier shape is designed to redirect vehicles, reducing the risk of vehicle median crossovers.
This design may also serve as a substitute for vertical or mountable curb in medians when access across the median is undesirable. The raised area behind the barrier can be either paved or used for landscaping.
View Low Profile Barrier (TB-13) plan sheet (PDF 1.45MB)
View Low Profile Barrier Type 2 (TB-14) plan sheet (PDF 1.41MB)
View Low Profile Barrier Type 3 (TB-15) plan sheet (PDF 1.54MB)
View Low Profile Barrier Nose (TB-16) plan sheet (PDF 1.51MB)
View Type 1 Low Profile Barrier transition to Traffic Curb (TB-17) plan sheet (PDF 1.27MB)
View Type 2 Low Profile Barrier transition to Traffic Curb (TB-18) plan sheet (PDF 1.33MB)
View Low Profile Barrier Placement (Precast) (TB-19) plan sheet (PDF 2.16MB)
View Low Profile Barrier Placement (Cast in place) (TB-20) plan sheet (PDF 1.78MB)
View Low Profile Barrier Placement with Traffic Curb Nose (TB-21) plan sheet (PDF 1.4MB)
This drawing shows the details necessary to construct a precast transition for a Type 2 concrete barrier to a precast single slope concrete barrier. This transition barrier requires installation below the finished pavement. It is commonly used when connecting a new run of single slope barrier to the older Type 2 (New Jersey shaped) concrete barrier.
View Precast Concrete Barrier Transition - Type 2 to Single Slope plan sheet (PDF 755KB)
These plans show all the details necessary to fabricate this barrier system.
This guardrail system may be used on designated scenic byways and heritage tour routes if funding can be arranged.
The Steel-backed Timber Guardrail system consists of a timber rail with a steel plate attached to the back to increase its tensile strength.
The most desirable method of terminating a run of Steel-backed Timber Guardrail is with a buried terminal in a backslope. When this is not feasible, the system is limited to use on highways with a posted speed of 45 mph or less, and the barrier run is required to flare away from the traveled way and terminate in a berm.
View Posted Steel-backed Timber Guardrail (TB-25) plan sheet (PDF 770KB)
View Posted Steel-backed Timber Guardrail Buried Anchor (TB-26) plan sheet (PDF 789KB)
View Steel-backed Timber Guardrail Non-flared Terminal (TB-27) plan sheet (PDF 1.2MB)
View W-Beam to timber Guardrail Transition (TB-28) plan sheet (PDF 844KB)
The old Type 3 anchor was primarily used at bridge ends. This anchor consisted of a steel pipe mounted vertically in a concrete foundation. Bridge approach guardrail was then mounted on the steel pipe.
On one-way highways, these anchors were usually positioned so that neither the anchor nor the bridge rail posed a snagging potential. When these cases are encountered, the anchor may remain in place if a stiffened transition section is provided at the connection to the post.
On two-way highways, the anchor may present a snagging potential. In these cases, install this retrofit connection from the anchor to the bridge rail if the offset from the bridge rail to the face of the guardrail is 1 foot 6 inches or less. If the offset is greater than 1 foot 6 inches, remove the anchor and install a new transition and connection.
There are two designs to choose from. Select the retrofit detail that is appropriate for achieving the desired rail height.
Before including these details in the Contract Documents, contact: Bill Berens HQ Design Office Bill.Berens@wsdot.wa.gov 360-705-7256
View Type 3 Guardrail Anchor Retrofit for Thrie Beam plan sheet (PDF 680KB)
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These details and plans are provided for information only. Type 1 guardrails are no longer used by WSDOT for new installations.
Used with Service Level 1 Bridge Rail The systems shown do not currently meet MASH requirements.
Type 20 and Type 21 guardrail are primarily used in conjunction with Service Level 1 bridges. Type 20 and Type 21 guardrail are TL-2 systems appropriate for speeds 45 mph or less.
This design has been utilized on some short concrete spans and timber bridges. A failure mechanism is built into this rail system so that upon impact the post will break away from the mounting bracket, ensuring minimal damage to the bridge. The thrie beam guardrail will contain the vehicle. Contact the Bridge & Structures Office for more information about Service Level 1 bridges.
For Type 20 guardrail and Type 21 guardrail, see TB-55: Beam Guardrail Type 20 & 21 (PDF 632KB), formerly Standard Plan C-1c.
Placement Case 14 applies to Service Level 1 bridge rail systems. Type 20 guardrail is used on the approach and no transition is needed between the Type 20 guardrail and the Service Level 1 bridge rail since they are both weak post systems. For Placement Case 14, see TB-56 Guardrail Placement Case 14 for Type 20 Guardrail (PDF 638KB), formerly Standard Plan C-2h.
A Type 6 transition (shown below) is used when connecting Type 20 guardrail to a strong post (Type 31) guardrail or a terminal. The Type 6 transition is needed to transition from the flexible Type 20 to the stiffer Type 31 guardrail.
For the Type 6 transition, see TB-C3a Type 1 Beam Guardrail Transition Sections (PDF 671KB) (Types 2, 4, 5, & 6)
Previously, WSDOT standard practice was to install W-beam guardrail at a rail height of 27 to 28 inches, referred to as “Type 1” guardrail. WSDOT introduced Type 31 guardrail in 2009 as the replacement for Type 1 guardrail. Type 1 guardrail is no longer used by WSDOT for new installations.
The following information and plans are provided for information only.
Previously, WSDOT standard practice was to install W-beam guardrail at a rail height of 27 to 28 inches, referred to as “Type 1” guardrail. WSDOT introduced Type 31 guardrail in 2009 as the replacement for Type 1 guardrail. Type 1 guardrail is no longer used by WSDOT for new installations. The following information and plans are provided for information only.
A buried terminal (BT) is designed to terminate the guardrail by burying the end into the backslope. The BT is the preferred terminal because it eliminates the exposed end of the guardrail and provides full shielding of the identified feature.
If a MASH compliant buried terminal is required for an existing guardrail run, use the buried terminal design for Type 31 guardrail and use the Type 31 to Type 1 adaptor.
The Buried Terminal uses a Type 2 anchor to develop the tensile strength in the guardrail. The backslope needed to install a BT is to be 3H:1V or steeper and at least 4 feet in height above the roadway. If the backslope is flatter than 1H:1V, provide a minimum 20-foot-wide by 75-foot-long distance behind the barrier and between the beginning length of need point at the terminal end to the mitigated object to be protected.
Flare the guardrail to the foreslope/backslope intersection using a flare rate that meets the criteria in 1610.04(5)(a). Provide a 4H:1V or flatter foreslope into the face of the guardrail and maintain the full guardrail height to the foreslope/backslope intersection in relation to a 10H:1V line extending from edge of shoulder breakpoint.
Length of need: The entire BT can be used within the length of need for backslopes of 1H:1V or steeper if the barrier remains at full height in relation to the roadway shoulder to the point where the barrier enters the backslope. For backslopes between 1H:1V and 3H:1V, design the length of need beginning at the point where the W-beam remains at full height in relation to the roadway shoulder - usually beginning at the point where the barrier crosses the ditch line.
See TB-C22.14, Beam Guardrail Type 1 (PDF 755KB) formerly Standard Plan C-22.14.
Informational only - The terminals shown on these plans are the terminals that were on the WSDOT Qualified Products List at the time of the specification change requiring MASH compliance for Type 1 guardrail terminals (April 2018). The terminals shown are not MASH compliant. The plans are provided for information only. See TB-C4b, Type 1 Beam Guardrail Flared Termina1 (PDF 673KB), formerly Standard Plan C-4b.
Image from Road Systems website
Flared terminal designs were used with Type 1 guardrail. The Slotted Rail Terminal (SRT) and the Flared Energy Absorbing Terminal (FLEAT) are two examples. With flared terminals it is important that the embankment quantity also be specified so that the area around the terminal can be constructed as shown in the Plans.
The SRT uses W-beam guardrail with slots cut into the corrugations and posts throughout the length of the terminal. The end of the SRT is offset from the tangent guardrail run by the use of a parabolic flare. When struck head on, the first two posts are designed to break away, and the parabolic flare gives the rail a natural tendency to buckle, minimizing the possibility of the guardrail end entering the vehicle. The buckling is facilitated by the slots in the rail. The remaining posts provide strength to the system for redirection and deceleration without snagging the vehicle. The SRT has a 4-foot offset at the first post.
The SRT terminal can be supplied with wood or steel posts. Match the type of SRT posts with those of the longitudinal barrier run to which the terminal will be connected.
The FLEAT uses W-beam guardrail with a special end piece that fits over the end of the guardrail and posts. The end of the FLEAT is offset from the tangent guardrail run by the use of a straight flare. When struck head on, the end piece is forced over the rail, bending the rail and forcing it away from the impacting vehicle.
The FLEAT is available in two designs based on the posted speed of the highway. For highways with a posted speed of 50 mph or above, use a FLEAT 350, which has a 4-foot offset at the first post. For highways with a posted speed of 45 mph or below, use a FLEAT TL-2, which has a 1-foot 8-inch offset at the first post. The FLEAT terminal can be supplied with wood or steel posts. Match the type of FLEAT posts with those of the longitudinal barrier run to which the terminal will be connected.
The length of need begins at the third post for both flared terminals.
Informational only - The terminal shown on this plan is the terminal that was on the WSDOT Qualified Products List at the time of the specification change requiring MASH compliance for Type 1 guardrail terminals (April 2018). The terminal shown is not MASH compliant. The plan is provided for information only. These systems use W-beam guardrail with a special end piece that fits over the end of the guardrail. When hit head on, the end piece is forced over the rail, absorbing the energy of the impacting vehicle in the process. An anchor is typically included for developing the tensile strength of the guardrail.
Non-flared terminals may be provided for two different design levels which are based on the posted speed of the highway. For highways with a posted speed of 50 mph or above, use only a TL-3 (Test Level 3) product. For highways with a posted speed of 45 mph or below, either a TL-2 or a TL-3 product is acceptable.
Although non-flared terminals do not need to have an offset at the end, a flare is recommended so that the end piece does not protrude into the shoulder. See the Plans.
Four feet of widening is needed at the end posts to properly anchor the systems. When widening includes an embankment, fill material will be necessary for optimum terminal performance (see the Plans).
One proprietary terminal is the Sequential Kinking Terminal (SKT). This terminal is available in two designs based on the posted speed of the highway. The primary difference in these designs is the length of the terminal. For highways with a posted speed of 50 mph or above, use the 50-foot-long SKT 350 (TL-3) terminal. For highways with a posted speed of 45 mph or below, use the 25-foot-long SKT-350 (TL-2).
The length of need does not begin at the impact head, but will vary by system.
See TB-C4e Type 1 Beam Guardrail Non-Flared Terminal (PDF 661KB), formerly Standard Plan C-4e.
Previously, WSDOT standard practice was to install W-beam guardrail at a rail height of 27 to 28 inches, referred to as “Type 1” guardrail. WSDOT introduced Type 31 guardrail in 2009 as the replacement for Type 1 guardrail. Type 1 guardrail is no longer used by WSDOT for new installations. The following information and plans are provided for information only.
When there is an abrupt change from one barrier type to a more rigid barrier type, a vehicle hitting the more flexible barrier may be caught in the deflected barrier pocket and directed into the more rigid barrier. This is commonly referred to as “pocketing.” A transition stiffens the more flexible barrier by decreasing the post spacing, increasing the post size, and using stiffer beam elements to reduce the possibility of pocketing.
Note: WSDOT introduced Type 31 guardrail in 2009 as the replacement for Type 1 guardrail. The guidance in the Design Manual regarding guardrail transitions was updated in 2009 to show Type 31 guardrail transitions instead of Type 1 guardrail transitions. As such, the May 2008 version of the Design Manual was the last Design Manual version to show complete guidance regarding transitions for Type 1 guardrail.
* See Detail Type E ~ Guardrail Connection to Bridge Rail or Concrete Barrier for 'E" Connection Option for TB-C-3, Type 1A.
Previously, WSDOT standard practice was to install W-beam guardrail at a rail height of 27 to 28 inches, referred to as “Type 1” guardrail. WSDOT introduced Type 31 guardrail in 2009 as the replacement for Type 1 guardrail. Type 1 guardrail is no longer used by WSDOT for new installations. The following information and plans are provided for information only.
A guardrail anchor is needed at the end of a run of guardrail to develop tensile strength throughout its length.
Type 1 anchors are used for (Old) Beam Guardrail Type 1 runs and can be used on either the upstream or downstream end located beyond the clear zone where a crash-tested terminal is not needed. See TB-C6 Beam Guardrail Type 1 Anchor (PDF 728KB), formerly Standard Plan C-6.
The Type 3 anchor was primarily used at bridge ends (see below). This anchor consisted of a steel pipe mounted vertically in a concrete foundation. Bridge approach guardrail was then mounted on the steel pipe.
On one-way highways, these anchors were usually positioned so that neither the anchor nor the bridge rail posed a snagging potential. When these cases are encountered, the anchor may remain in place if a stiffened transition section is provided at the connection to the post.
On two-way highways, the anchor may present a snagging potential. In these cases, install a connection from the anchor to the bridge rail if the anchor’s lateral offset from the bridge rail to the face of the guardrail is 1-foot 6-inches or less. If the offset is greater than 1-foot 6-inches, remove the anchor and install a new transition and connection.
No plan is available for the Type 3 anchor. Also see TB50 for additional information.
Type 4 anchors are used for (Old) Beam Guardrail Type 1 where a crash-tested terminal is not needed. See TB-C6c Beam Guardrail Type 4 Anchor (PDF 670KB), formerly Standard Plan C-6c.
Type 5 anchors are used for (Old) Beam Guardrail Type 1 with the Weak Post Intersection Design, see placement cases 12 and 13. See TB-C6d Beam Guardrail Type 5 Anchor (PDF 669KB), formerly Standard Plan C-6d.
Type 7 anchors are used for (Old) Beam Guardrail Type 1 to develop tensile strength in the middle of a guardrail run when the guardrail curves and weak posts are, see placement cases 9, 12, and 13. See TB-C6f Beam Guardrail Type 7 Anchor (PDF 638KB), formerly Standard Plan C-6f.
Previously, WSDOT standard practice was to install W-beam guardrail at a rail height of 27 to 28 inches, referred to as “Type 1” guardrail. WSDOT introduced Type 31 guardrail in 2009 as the replacement for Type 1 guardrail. Type 1 guardrail is no longer used by WSDOT for new installations. The following information and plans are provided for information only.
Type 1 Guardrail has a height of 27 to 28 inches, utilizes 8” block-outs and the bolts that connect rail elements are located between posts. See TB-C1 Beam Guardrail Types 1-4 (W beam)(PDF 887KB), formerly Standard Plan C-1.
“Type 1 Alternate” guardrail is a version of Type 1 guardrail that has holes pre-drilled to allow raising of the blocks and rail element after a future overlay. See TB-C1 Beam Guardrail Types 1-4 (W beam)(PDF 887KB), formerly Standard Plan C-1.
W-beam guardrail Type 2 and Type 3 have a height of 30 inches and utilize a rubrail. A rubrail is a structural steel channel added below the W-beam rail and is used in these specific designs to reduce vehicle snagging on the post. See TB-C1 Beam Guardrail Types 1-4 (W beam)(PDF887KB), formerly Standard Plan C-1.
Type 4 guardrail is a double-sided version of the Type 1 guardrail system. For new installations WSDOST uses the Type 31 double-sided w-beam guardrail instead of Type 4 guardrail. See TB-C1 Beam Guardrail Types 1-4 (W beam) (PDF 887KB), formerly Standard Plan C-1.
This transition is used to connect thrie beam to a rigid barrier.
See TB-C301 Thrie Beam Transition Type 1B (PDF 629KB), formerly Standard Plan C-3.
Previously, WSDOT standard practice was to install W-beam Type 1 guardrail on top of a concrete box culvert at a rail height of 27 to 28 inches utilizing steel posts anchored to the box culvert. WSDOT introduced Type 31 guardrail in 2009 as the replacement for Type 1 guardrail. Type 1 guardrail is no longer used by WSDOT for new installations. The following information and plans are provided for information only.
Guardrail installations along the roadway may require placement over an existing or new reinforced concrete box culvert.
See TB-C10 Box Culvert Guardrail Steel Post (PDF 799KB), formerly Standard Plan C-10.
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