Barrier Warrant Process - Illinois Tollway

Tracy Borchardt April 2013

Barrier Warrant Process

1

Traffic Barrier Warrants Each roadside barrier and safety appurtenance

installed on the Tollway System needs to be justified and the analysis documented.

2

Traffic Barrier Guidelines

3

• BWA Process

• Usage Guide

March 2013

References

AASHTO Roadside Design Guide, 4th Edition-2011

Clear Zone, Chapter 3

Location of Barriers, Chapter 5

Barrier Length & End Treatment, Chapter 5

Benefit/Cost Analysis

4

POTENTIAL ROADSIDE OBSTACLES

TBG – SECTION 3.0

5

Potential Roadside Obstacles

Design Options:

1. Remove obstacle

2. Relocate obstacle

3. Reduce impact severity.

4. Shield obstacle.

5. Delineate obstacle.

6

Potential Roadside Obstacles

Gutters and Curbs

Embankments

Sign Supports

Bridge Piers, Parapets, Abutments & Bridge Cones

Noise Abatement Wall

Drainage Structures

Ditches

Riprap

Roadway Lighting

ITS Systems

Utility Poles

Trees

Bodies of Water

Rock Cuts

7

Gutters and Curbs

Type C Curb

Type G-3 Modified Gutter

Type G-3 Gutter

8

Type G-3 Gutters

9

Type G-2 Gutters

10

Gutter and Guardrail

G-3 Modified Gutter G-3 Gutter

11

Gutter may be constructed in conjunction with guardrail, but is not required

solely because of the presence of guardrail and vice versa.

Guardrail shall not be constructed to shield improperly placed gutter or curb.

Guardrail

Embankments

Roadside Geometry and Terrain Features ,

Section 5.2.1 of the AASHTO Guide.

12

Comparative Risk Warrants for Embankments (RDG Fig. 5-1b)

13

Sign Supports

Overhead Sign Truss – Cantilever Type

Overhead Sign Truss – Span Type

14

Bridges

Pier

Abutment Cone

Economical bridge designs usually result in the location of bridge piers, abutments, and parapets within mainline or ramp clear zones.

Parapets

15

Noise Abatement Wall

Non-Crashworthy Noise Wall

Crashworthy Noise Wall

16

Drainage Structures

Issues:

•Headwall not flush with embankment

•Pipe too short

•Headwall too close to roadway

•Steep slope just above headwall

•Skew

17

Drainage Structures- Corrected

18

Safety End Treatment

19

Ditches

Drainage Channels, Section 3.2.4 of the AASHTO Guide.

20

Roadway Lighting

21

Roadway Lighting (cont.)

Controllers and Transformers

22

Communication Systems and ITS Devices

NID RWIS CCTV Camera

Non-Breakaway 23

Bodies of Water

Bodies of water greater than 2’ in depth must be shielded.

Locate detention basins well outside the clear zone.

24

BARRIER WARRANT ANALYSIS PROCEDURE

TBG – SECTION 4.0

25

Barrier Warrant Analysis Procedure

1. Identify Potential Obstacles

2. Name Obstacles

3. Prepare/Present Exhibit (Concept Meeting)

26


1. Identify Potential Obstacles.

2. Name Obstacles.

3. Prepare/Present Exhibit.

4. Each AOC shall be analyzed separately.

a. Establish EOTW

27

a. Establish Edge of Traveled Way

EOP 1’ outside of the EOTW

EOTW = EOP

28



2. Name Obstacles.



a. Establish EOTW

b. Design Speed (Speed Profile for ramps, etc.)

29



2. Name Obstacles.



a. Establish EOTW

b. Design Speed

c. Design ADT

30



2. Name Obstacles.



a. Establish EOTW

b. Design Speed

c. Design ADT

d. Length of Runout

31

c. Length of Runout

L2

Figure 5-39. Approach Barrier Layout Variables

LR

32



2. Name Obstacles.



a. Establish EOTW

b. Design Speed

c. Design ADT

d. Length of Runout

e. Shy Line Offset

33

d. Shy Line Offset

34



2. Name Obstacles.



a. Establish EOTW

b. Design Speed

c. Design ADT

d. Length of Runout

e. Shy Line Offset

f. Foreslope/Backslope

35

f. Foreslope/Backslope

Foreslope

Backslope

Foreslopes

Within clear zone Elsewhere

1:6 (desirable) 1:4 (desirable)

1:4 (maximum) 1:2.5 (maximum)

Backslopes

1:4 or flatter (desirable)

1:2.5 (maximum)

V1:H1

V2:H2

36

Barrier Warrant Analysis Procedure (cont.)

g. Clear Zone

37

Clear Zone

The unobstructed, traversable area provided beyond the edge of through traveled way for the recovery of errant vehicles.

38

Clear Zone Distances (Feet) From Edge of Traveled Way (Table 3-1)

Use highest value in range 39


g. Clear Zone

h. Clear Zone Adjustment

40


41


g. Clear Zone


i. Lateral Extent of the Area of Concern (LA)

42

i. Lateral Extent of the Area of Concern

L2


LA

L3

43


g. Clear Zone



j. Warrant Analysis Level

44


Decide Warrant Analysis Level

Level 1

Level 2

Level 3

Level 0

Use

Flowchart For Existing

Obstacles

or

Flowchart for Proposed

Obstacles

45

Warrant Analysis Level (Article 5.5)

46

Flowchart for Analysis of Existing Obstacles

47

Flowchart for Analysis of Proposed Obstacles

48

Level 1 Analysis

Level 1 – Existing AOC’s that are traversable elements or can easily be made traversable elements such as:

Existing ground mounted signs, and existing drainage items

Existing ground mounted light poles and electrical handholes

49

Level 1 Analysis

Level 1 – Proposed AOC’s that are traversable elements:

Proposed Ground-Mounted Signs

Proposed light poles

Proposed Drainage Items (culvert and pipe ends 84” or less in vertical opening)

50

Traversable Element

RDG-Figure 4-1. Breakaway Support

Stub Height Measurements

51

4 in.

Traversable Element

4’

1:6

(V:H)

52

Breakaway Sign Supports

An important feature of this breakaway sign system is the ability of its post support to swing up and out of the way when it is struck by an errant vehicle.

53

Safety End Treatment-Steel Grate

Headwall and storm sewer outlets shall be provided with appropriate safety end treatment per Standard Drawings – Section B.

54

Roadway Lighting

Steel Helix Foundation

Needs to be a Traversable

Element

55

Level 2 Analysis

When shielding is required and barrier length of need must be determined.

Cantilever sign post

56

Level 2 Analysis

This analysis is performed for:

EXISTING/PROPOSED OBSTACLES when there are no feasible alternatives for eliminating, or reducing the impact severity of the obstacle.

PROPOSED OBSTACLES for an Alternative in a Level 3 Analysis. The length of barrier and type of terminals has to be determined for each Alternative that involves shielding of the obstacle.

57

Level 3 Analysis

The evaluation of 2 or more possible alternatives for eliminating or reducing the obstacle.

Only consider alternatives that are feasible.

Cannot analyze an alternative that leaves an obstacle unshielded in the clear zone.

This is part of the design process

58

Roadside Safety Analysis Program (RSAP)

http://rsap.roadsafellc.com/

59

Level 3 Analysis

Overhead sign to span roadway with barrier

Overhead sign to span beyond clear zone with no barrier

60

This is most

common Level 3

obstacle


g. Clear Zone




k. Lateral Offset of Barrier (L2)

61

k. Lateral Offset of Barrier

L2


L2

62


2’- 2 ¾” With Type G-3 Gutter

63

k. Lateral Offset of Barrier 1’-0” Without Gutter


g. Foreslope/Backslope

h. Clear Zone

i. Clear Zone Adjustment



l. Upstream End of Guardrail

65


L2


Point of Need

66


g. Clear Zone






m. Upstream End of Barrier Wall

67


A = Suggested maximum flare rate for rigid barrier system.

B = Suggested maximum flare rate for semi-rigid barrier system.

68


g. Clear Zone







n. Downstream Terminal

69


Traffic Barrier Terminal Type T2

Traffic Barrier Terminal Type T6

70


g. Clear Zone








o. Barrier Obstacle

71


g. Clear Zone








o. Barrier Obstacle

p. Compare existing length to proposed

72


g. Clear Zone








o. Barrier Obstacle

p. Compare existing length to proposed

q. Prepare warrant text and exhibits

73

PRESENTATION OF BARRIER WARRANT

ANALYSIS TBG – SECTION 6.0

74

Presentation of Barrier Warrant Analyses

Samples

Speed Profile

Location Plan

Level 1 Table

Data Sheet

Calculation sheet

Site Plan

RSAP Feature Sketch

Level 0 Table

75

Presentation of Barrier Warrant Analysis

Checklists

Cover Sheet

Table of Contents

Disposition

Location Plan

Data Sheet

Calculation Sheet

Site Plan

Summary Site Plan

Cross Sections

Level 0 Table

Level 1 Analysis

Level 2 Analysis

Level 3 Analysis

76

BARRIER WARRANT SUBMITTAL SCHEDULE

TBG – SECTION 7.0

77

Submittal Schedule

Barrier Warrant Analysis is part of the Design Process.

Barrier Warrants are not considered final until there are no further review comments on the final submittal.

78

Concept Meeting

The general goals of the meeting are to:

Provide an overview of the project limits, scope of work, and any omissions

Summarize the overall project schedule

Discuss potential AOC’s and barrier warrant analysis methodology

Present unique project issues

Identify locations that are good candidates to be included in the preliminary submittal.

79

Preliminary Submittal Barrier Warrant Analysis shall be submitted with

the Preliminary Plans.

Submit a minimum of five sample locations

At least two Level 2

At least two Level 3 with RSAP output and feature sketch

It is recommended that Designer choose locations that may require more review cycles, are more complex or require extra coordination.

Submit one page of the Level 1 Table (at least 4 AOC’s)

Submit Completed Checklist.

80

Pre-Final Submittal Barrier Warrant Analysis shall be submitted with

the Pre-Final Plans.

Similar to Pre-Final Plans, the Pre-Final Barrier Warrant shall be considered 100% complete.

All comments on preliminary submittal addressed and a disposition provided.

Submit completed checklist.

All above materials shall be submitted through the Tollway’s web-based project management system and in hard copy format.

81

Final Submittal

DSE Final Barrier Warrant shall match the DSE plans submitted for advertisement.

Final Barrier Warrant Analysis should be complete at the Final Plan Check.

All previous review comments addressed and a disposition provided.

Submit completed checklist.

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Barrier Warrant Amendment Process

83

What

initiated

change to

design?

Who

initiated

change?

Who

completes

Amendment

to BWA?

In addition to

GEC, who

reviews BWA

Amendment?

Field

change

CM or

Contractor DSE CM

Field Change


84

What

initiated

change to

design?

Who

initiated

change?

Who

completes

Amendment

to BWA?

In addition to

GEC, who

reviews BWA

Amendment?

Value

Engineering

Proposal

Contractor Contractor’s

Designer DSE & CM

Value Engineering Proposal


85

What

initiated

change to

design?

Who

initiated

change?

Who

completes

Amendment

to BWA?

In addition to

GEC, who

reviews BWA

Amendment?

Performance

Based

Design

Contractor Contractor’s

Designer DSE & CM

Performance Based Design

Record

Drawings

Field

Conditions

Final Amended

Barrier Warrant

3 Components must be equal

=

=

86

Questions ?

E-Mail: [email protected]

87

mailto:[email protected]

Closing Remarks

Fill out the comment sheet

Take PDH forms

Contact any of the presenters with questions

PowerPoint presentations will be posted to the Tollway website after the 3rd session

Barrier Warrant Process - Illinois Tollway

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