TECHNICAL REPORT STANDARD TITLE PAGE

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.

FHWATX77-225-1 4. Title and Subtitle 5. Report Date

"Safety Treatment of Roadside Culverts on Low Volume March 1978 Roads" 6. Performing Organization Code

7. Author(s} 8. Performing Organization Report No.

T. L. Kohutek and H. E. Ross, Jr. Research Report 225-1

9. Performing Organization Name and Address 10. Work Unit No.

Texas Transportation Institute Texas A&M University 11. Contract or Grant No.

College Station, Texas 77843 Research Study 2-8-77-225 13. Type of Report ,and Period Covered

12. Sponsoring Agency Nome and Address Final Report Texas State Department of Highways and Public Transportation January 1977 - March 1978

Transportation Planning Division 14. Sponsoring Agency Code

P.O. Box 5051 Austin, Texas 78763 15. Supplementary Notes

Research performed in cooperation with DOT, FHWA. Research Study Title: "Economics of Highway Design Alternatives ll

• SDHPT Contact Man: Harold Cooner, FHWA Contact Man: C. P. Damon

16. Abstract

Current American Association of State Transportation and Highway Officials (AASHTO) criteria for safety-treating fixed roadside hazards suggest that all culverts within a certain clear distance of the edge of the traveled way be shielded by a roadside barrier. This is not necessarily a cost-effective solution for low volume highways.

Using a cost-effectiveness model currently recommended by AASHTO. guidelines for safety-treating culverts have been developed for 36 in. diameter pipe, 4 ft x 6 ft (4 ft height x 6 ft width) single box, and 4 ft x 6 ft multi-box (double box) culverts located on low volume, rural highways (average daily traffic less than 20,000). Each culvert design was evaluated on fill section embankments with 2~:1 and 6: 1 slopes and for end offsets of 12, 18, and 24 ft. The treatments considered for each culvert design and embankment slope were: 1) do nothing (i.e., leave the culvert unprotected); 2) extend the culvert end 30 ft from the edge of the traveled way; 3) provide guardrail protection; and 4) provide grate protection.

17. Key Words 18. Distribution Statement

Cost-Effectiveness, Culvert, Grates, No restrictions. This document is Guardrail, Roadside Barriers, Safety available to the public through the Treatment, Severity Index National Technical Information Service,

Springfield, Virginia 22161

19. Security Clossil. (of this report) 20. Security Clossif. (of this page) 21. No. of Pages 22. Price

Unclassified Unc 1 ass ifi ed 111 N/A

Form DOT F 1700.7 (B.6.' i

SAFETY TREATMENT

OF ROADSIDE CULVERTS

ON LOW VOLUME ROADS

by T. L. Kohutek

Engineering Research Associate

and

H. E. Ross, Jr. Research Engineer

Research RepoY't 225-1 Economics of Highway Design Alternatives

Research Study 2-8-77-225

Sponsored by The Texas State Department of Highways and Public Transportation

in cooperation with The United States Department of Transportation

Federal Highway Administration

March 1978

Texas Transportation Institute Texas A&M University

College Station, Texas

i i

FOREWORD

The information contained herein was developed on Research Study

2-8-77-225 entitled "Economics of Highway Design Alternatives. II It

is a cooperative research study sponsored jointly by the Texas State

Department of Highways and Public Transportation and the u. S. Depart­

ment of Transportation, Federal Highway Administration.

The objective of the study is to develop guidelines for installing,

upgrading, and safety-treating various types of culvert designs. Empha­

sis is placed primarily on culverts located on low volume roads (3,000

average daily traffic and less) although some work is done with inter­

mediate volumes (20,000 average daily traffic).

A cost-effectiveness model was taken from the American Association

of Highway and Transportation Officials (AASHTO) guide for the selecting,

locating, and designing of highway traffic barriers (l). This model

provides the present value of the total cost of each alternative as

computed over a given period of time taking into consideration initial

construction costs, maintenance costs, and accident costs. Accident

costs incurred by the motorist, including vehicle damage and personal

injury, are considered together with damage costs incurred by the

highway department.

A ranking factor for each alternative is also calculated to aid

the designer in establishing a priority system for reducing culvert

hazards within a given roadway system. This factor is a ratio of the

benefits (as measured in accident cost savings) received to direct costs

incurred by the highway department when selecting an alternative.

iii

The alternative with the highest ranking factor (or benefit to cost

ratio) is generally the most desirable.

The contents of this report reflect the views of the authors who

are responsible for the facts and the accuracy of the data presented

herein. The contents do not necessarily reflect the official views

or policies of the Federal Highway Administration. This report does

not constitute a standard, specification, or regulation.

iv

SUMMARY

Key Words: Cost-Effectiveness, Culverts, Grates, Guardrail, Roadside

Barriers, Safety Treatments, Severity Index.

Current American Association of State Transportation and Highway

Officials (AASHTO) criteria for safety-treating fixed roadside hazards

on high-speed facilities suggest that all culverts within a certain

distance of the edge of the traveled way be shielded by a roadside

barrier (1). In a restricted highway funding environment, this is not

necessarily a cost-effective solution for low volume highways.

Using a cost-effectiveness model currently recommended by AASHTO (1),

warrants for safety-treating culverts have been developed for 36 in.

diameter pipe, 4 ft x 6 ft (4 ft height x 6 ft width) single box, and

4 ft x 6 ft multi-box (double box) culverts located on low volume, rural

highways (average daily traffic less than 20,000). Each culvert design

was evaluated on fill section embankments with 2~:1 and 6:1 slopes and

for end offsets of 12, 18, and 24 ft. The treatments cons i dered for

each culvert design and embankment slope were: 1) do nothing (i.e.,

leave the culvert unprotected); 2) extend the culvert end 30 ft from the

edge of the traveled way; 3) provide guardrail protection; and 4) provide

grate protection.

Figures are given to identify cost-effective treatments for the

range of variables (ADT, embankment slope, offset, culvert design and

safety treatment, etc.) considered in this study. For traffic volumes

less than 750 and offset distances greater than 12 ft, the most cost­

effective alternative is to leave the culvert unprotected. At higher

traffic volumes the most cost-effective safety treatments are extending

v

the culvert end to 30 ft or grating. Guardrail was found to be cost­

effective only for larger culvert sizes and higher traffic volumes.

However, guardrail protection was not the most cost-effective alterna­

tive for these situations.

All supporting data and a discussion of the cost-effectiveness

model used in the study are included in this report. Examples are

given to illustrate the use of the criteria developed and to show the

techniques used to develop these criteria. Other examples are included

to enable the user to develop warrants for situations other than those

considered in this study.

vi

IMPLEMENTATION

Generally, there are three alternatives to evaluate when con­

sidering th~ safety treatment of any roadside hazard: 1) do nothing,

i.e., leave hazard unshielded; 2) remove or reduce hazard so that

shielding is unnecessary; or 3) install a barrier.

second alternative may be accomplished as follows:

For culverts, the

1) extend the ends

of the culvert a sufficient distance from the edge of the traveled way

to allow an errant vehicle time and space to return to the road; and/or

2) "reduce" the hazard by providing grate treatment.

Extensive research has been performed to develop guidelines for

safety-treating many types of roadside hazards, but little effort has

been made to develop objective criteria for safety-treating culverts.

This study provided objective criteria for the safety treatment of

36 in. diameter pipe, 4 ft x 6 ft single box, and 4 ft x 6 ft multi-box

(double) culvert designs on both flat and steep roadside slopes and low

volume highways. For each of these configurations, the alternatives

discussed previously were considered as possible treatments. The

criteria developed in this study will aid the highway designer in two

ways. He will be able to (1) determine the most cost-effective safety

treatment for existing culverts, or (2) design the most cost-effective

culvert installation for new roadways. The same basic procedure used

in this study may be used to develop objective criteria for other

culvert designs on higher volume highways.

vii

ACKNOWLEDGMENTS

This study was conducted under a cooperative program between

the Texas Transportation Institute and the Texas State Department of

Highways and Public Transportation (SDHPT). It was sponsored by SDHPT

in cooperation with the U.S. Department of Transportation, Federal

Highway Administration (FHWA).

The authors wish to thank Mr. Harold Cooner of SDHPT and Mr. C.

P. Damon of FHWA for their opinions, guidance, and technical assistance

throughout the study. Thanks should also be extended to Mr. Dan Williams

of SDHPT for providing cost estimates for the various types of culvert

designs and grate protection safety treatments. Special thanks go to

Mrs. Sheila Darsie for her typing skills and overall assistance in

preparing this report. Mrs. Sylvia Velasco also helped type the final

manuscript.

viii

TABLE OF CONTENTS

Page

I. INTRODUCTION 1

I I. CULVERT DESIGNS AND TREATMENTS 3

General 3 Range of Variables 3 Assumptions and Limitations 9

III. GUIDELINES FOR EXTENDING OR UPGRADING EXISTING UNPROTECTED CULVERTS 11

IV. CONCLUSIONS AND RECOMMENDATIONS 32

V. FUTURE CONSIDERATIONS 35

APPENDICES 36

APPENDIX A. A DISCUSSION OF THE COST-EFFECTIVENESS MODEL Al

APPENDIX B. APPLICATION OF MODEL Bl APPENDIX C. SUPPORTING DATA Cl APPENDIX D. SAMPLE CALCULATIONS 01 APPENDIX E. REFERENCES El

ix

LIST OF FIGURES

Figure Page

1 TYPICAL ROADWAY SECTION WITH THE VARIOUS CULVERT DESIGNS 4

2 CULVERT SAFETY TREATMENTS 6

3 WARRANTS FOR EXTENDING OR UPGRADING A 36 INCH PIPE CULVERT ON A 2~:1 SLOPE 12

4 WARRANTS FOR EXTENDING OR UPGRADING A 36 INCH PIPE CULVERT ON A 6:1 SLOPE 13

5 WARRANTS FOR EXTENDING OR UPGRADING A 41 X 61 SINGLE BOX CULVERT ON A 2~:1 SLOPE 14

6 WARRANTS FOR EXTENDING OR UPGRADING A 41 X 61 SINGLE BOX CULVERT ON A 6:1 SLOPE 15

7 WARRANTS FOR EXTENDING OR UPGRADING A 41 X 61 MULTI-BOX (2) CULVERT ON A 2~:1 SLOPE 16

8 WARRANTS FOR EXTENDING OR UPGRADING A 41 X 61 MULTI-BOX (2) CULVERT ON A 6:1 SLOPE 17

9 SAMPLE ADT INTERPOLATION FOR UNITY RANKING FACTOR 20

10 COST-EFFECTIVENESS CURVES FOR TYPICAL CULVERT ENDS ON 2~:1 SLOPES 21

11 COST-EFFECTIVENESS CURVES FOR TYPICAL CULVERTS ON 6:1 SLOPES 22

12 POSSIBLE DESIGN GUIDELINES FOR TYPICAL CULVERTS ON 6:1 SLOPES 23

13 POSSIBLE DESIGN GUIDELINES FOR TYPICAL CULVERTS ON 6:1 SLOPES AND SMALL (36 11 DIA.) CULVERTS ON STEEP SLOPES 24

14 POSSIBLE DESIGN GUIDELINES FOR TYPICAL CULVERTS ON 6: 1 SLOPES AND St~ALL (36" DIA.) CULVERTS ON STEEP SLOPES 25

15 POSSIBLE DESIGN GUIDELINES FOR TYPICAL CULVERTS ON 6:1 SLOPES 26

16 POSSIBLE DESIGN GUIDELINES FOR TYPICAL CULVERT ENDS ON STEEP SLOPES 27

x

Figure

17

18

A1

A2

A3

LIST OF FIGURES (continued)

POSSIBLE DESIGN GUIDELINES FOR TYPICAL CULVERT ENDS ON STEEP SLOPES

POSSIBLE DESIGN GUIDELINES FOR ALL CULVERT ENDS ON STEEP SLOPES

HAZARD ENVELOPE FOR AN UNPROTECTED CULVERT AND DITCH

HAZARD ENVELOPE FOR GUARDRAIL PROTECTED CULVERT

HAZARD ENVELOPE FOR GRATE PROTECTED CULVERT

xi

28

29

A3

A4

A5

Table

1

Al

A2

Bl

B2

B3

B4

B5

B6

B7

B8

Cl

C2

C3

C4

C5

LIST OF TABLES

INTERPOLATED ADT VOLUMES FOR RANKING FACTOR = 1.0

VALUES FOR CALCULATING THE COLLISION FREQUENCY (CF)

SEVERITY INDEX AND ACCIDENT COST

SEVERITY INDICES AND ACCIDENT COSTS FOR THE UNPROTECTED CULVERT

COST OF WING WALLS (CWW)

COST OF EXTENDING THE CULVERT PIPE OR BOX TO 30 FT FINAL OFFSET (CEXT)

COST OF FILL FOR EXTENDING THE CULVERT TO 30 FT FINAL OFFSET (CFILL)

INITIAL COST OF GRATE PROTECTION

DIRECT COSTS FOR EXTENDING A CULVERT TO 30 FT FINAL OFFSET

DIRECT COSTS FOR GUARDRAIL PROTECTION OF 36 IN. PIPE, 4 FT X 6 FT SINGLE BOX, AND 4 FT X 6 FT MULTI-BOX (2) CULVERTS ON 2~:1 AND 6:1 SLOPES

DIRECT COSTS FOR GRATE PROTECTION

RANKING FACTORS FOR A 36 INCH PIPE CULVERT ON A 2~:1 SLOPE

RANKING FACTORS FOR A 36 INCH PIPE CULVERT ON A 6:1 SLOPE

RANKING FACTORS FOR A 41 X 61 SINGLE BOX CULVERT ON A 2~:1 SLOPE

RANKING FACTORS FOR A 41 X 61 SINGLE BOX CULVERT ON A 6:1 SLOPE

RANKING FACTORS FOR A 41 X 61 MULTI-BOX (2) CULVERT ON A 2~:1 SLOPE

xii

19

A7

A8

B2

B3

B4

B5

B7

B9

B10

B10

C2

C5

C8

Cll

C14

LIST OF TABLES (continued)

Table Page

C6 RANKING FACTORS FOR A 41 X 61 MULTI-BOX (2) CULVERT ON A 6:1 SLOPE C17

C7 TOTAL COST DATA FOR A 36 INCH PIPE CULVERT ON A 2~:1 SLOPE C20

C8 TOTAL COST DATA FOR A 36 INCH PIPE CULVERT ON A 6:1 SLOPE C24

C9 TOTAL COST DATA FOR A 41 X 61 SINGLE BOX CULVERT ON A 2~:1 SLOPE C28

Cl0 TOTAL COST DATA FOR A 41 X 61 SINGLE BOX CULVERT ON A 6:1 SLOPE C32

Cll . TOTAL COST DATA FOR A 41 X 61 MULTI-BOX (2) CULVERT ON A 2~:1 SLOPE C36

C12 TOTAL COST DATA FOR A 41 X 61 MULTI-BOX (2) CULVERT ON A 6:1 SLOPE C40

C13 DIRECT COST DATA FOR A 36 INCH PIPE CULVERT ON A 2~:1 SLOPE C44

C14 DIRECT COST DATA FOR A 36 INCH PIPE CULVERT ON A 6:1 SLOPE C45

C15 DIRECT COST DATA FOR A41 X 61 SINGLE BOX CULVERT ON A 2~:1 SLOPE C46

C16 DIRECT COST DATA FOR A 41 X 61 SINGLE BOX CULVERT ON A 6:1 SLOPE C47

C17 DIRECT COST DATA FOR A 41 X 61 MULTI-BOX (2) CULVERT ON A 2~:1 SLOPE C48

C18 DIRECT COST DATA FOR A 41 X 61 MULTI-BOX (2) CULVERT ON A 6:1 SLOPE C49

xiii

I. INTRODUCTION

Vehicle collisions with roadside hazards are inherent to any

existing highway facility. As highway improvement plans are prepared

to minimize these hazards, it is essential in a restricted funding

environment that final designs and alternatives be cost-effective to

the highway department.

A common and dangerous roadside hazard is the open-ended culvert.

There is little question that a collision with such a hazard can result

in property damage and serious personal injury or possible fatalities.

Culvert ends merit systematic and objective evaluation so that the most

cost-effective safety treatment will be utilized.

Barrier warrants for fixed objects on high-speed facilities (1)

suggest that all culverts within a predetermined "clear zone" be shielded

by a roadside barrier. However, the guide (1) also encourages the

application of a cost-effective procedure to provide an objective method

of comparing alternate safety treatments for problem hazards such as the

culvert. The options of lido nothingll, i.e., leaving the hazard

unshielded, and reduce or remove the hazard become possible safety

treatments on low volume facilities where the probability of accidents

is low.

There are many variables to consider in the safety treatment of

any culvert design. Among these variables are the traffic volume, cul­

vert size, culvert end offset distance, and the various available safety

treatment designs. Chapter II discusses the range of those variables

considered, along with the assumptions and limitations made in this

1

study. Chapter III contains the safety treatment guidelines, and

Chapter IV contains the conclusions. DetaiZs of the cost-effective

methodoZogies used in deveZoping the guideZines are presented in the

Appendix.

2

II. CULVERT DESIGNS AND TREATMENTS

General

The culvert designs and treatments studied are those that would

typically exist along low volume (average daily traffic less than 5000),

high-speed, rural facilities. Figure 1 shows a typical rural roadway

section considered in the study.

Range of Variables

The range of variables considered are listed below.

1) Culvert Size. Three typical sizes of culverts shown in

Figure 1, namely, the 36 in. diameter pipe, the 4 ft x 6 ft single box,

and the 4 ft x 6 ft multi-box (or double box) were studied.

2) Culvert Safety Treatments. Four safety treatment alternatives

were considered. These were: do nothing (i.e., provide no shielding

for the culvert), extend the culvert end to 30 ft from the edge of the.

traveled way, install guardrail, and place a grate over the culvert end.

These safety treatments are shown in Figure 2. Note that added fill

material is required when the culvert end is extended as shown in

Figure 2. Cost of the added fill was included in the analysis.

3) Traffic Volumes. Average daily traffic (ADT) ranged from 750

to 20,000 with emphasis placed on ADT's below 3000.

4) Original Culvert End Offset. Three offset distances -- 12, 18

and 24 ft -- were studied.

5) Embankment Slope. Culverts located on fill sections with

slopes of 2~:1 and 6:1 were studied.

3

Original Culvert End Offset 1

~----+- 30' Hazard Zone----'

Traveled Way ------'1-.. Shoulder 100-.--

8'-~- 12' --.J-- 12' ---t-- 8'

FIGURE 1. TYPICAL ROADWAY SECTION WITH THE VARIOUS CULVERT DESIGNS

(J1

Fill- Section

--,---3'or 4' __ 1 __ _

VIEW A- A

Wj,ng Wall

B

B

1----. 6'-~

VIEW B-B 4' X 6' SINGLE BOX 'CULVERT

CULVERT DESIGN 2

VIEW B-B 36" PIPE CULVERT

CULVERT DESIGN I

..-.-- 6' ------I ~- 6' ---.-I

VIEW B-B

4' X6' MULTI- BOX CULVERT CULVERT DESIGN 3

FIGURE 1 (CONTINUED). TYPICAL ROADWAY SECTION WITH THE VARIOUS CULVERT DESIGNS

A, I

A I

2

ORIGINAL

2 1/2: I

ui OR a: ~ 6: I o· w W SLOPE

FILL ADDED

E.O.P. -EDGE OF PAVEMENT E.O.S. - EDGE OF SHOULDER

SAFETY TREATMENT, 1 - EXTEND TO 30ft.

}._-------, ,

- .. -------- -~- ---------------------------~-....-

GROUND

-SECTION A - A _ LINE -....=.=:...;..:..~~ 1 - 1,--

FIGURE 2. CULVERT SAFETY TREATMENTS. 6

12'

-- --

-- --

B

10'

-\

---=( ---

25' END TREATMENT

150' or

...-. ...... - - - ..... - .... ----.-.. 200'

VARIABLE

25' END TREATMENT

1

SAFETY TREATMENT 2 - GUARDRAIL PROTECTION

I

WAY SHOULDER NOTE: GUARDRAIL IS A NON-TRAVELEDLf

-.

. BLOCKED, 12GA. W-BEAM RAIL

ON A ?,'DIA. TIMBER POST. @ 6'-3" SPACING. END TREAT-

I MENT IS GEET I BY AASHTO - I .-

-- 2-2

or6 GUIDELINES ill ----------" - -

L_______ _ r-- ------------

SECTION B- B FIGURE 2 (CONTINUED). CULVERT SAFETY TREATMENTS

7

FLAT BAR

CHANNEL

SAFETY TREATMENT 3- GRATE PROTECTION

HEIGHT OF

CULVERT

....... " - TOP .. VIEW

SIDE VIEW

FIGURE 2 (CONTINUED). CULVERT SAFETY TREATMENTS

8

Assumptions and Limitations

A certain number of assumptions and limitations were essential in

the development of the cost-effectiveness model used in this study.

Discussion of the basic assumptions, including encroachment rates and

severity indices with their related accident costs, can be found in the

AASHTO guide (1). Listed below are assumptions that were made in

addition to those necessary to develop the model:

1) ADT would remain relatively constant for the highway design

life (20 years).

2) The ditch at the culvert end will have 2:1 sloping walls and

the depth of the ditch will be half the height of the culvert.

3) The wing walls of the culvert will be the same slope as the fill

section (2~:1 or 6:1).

4) Grates placed on any culvert end will be designed such that it

is traversable and can support a 4500 lb vehicle under anticipated

dynamic loads.

5) A vehicle leaving the traveled way would have redirection

capabilities on a 6:1 fill section but not on a 2~:1 fill

section.

6) For all culvert sizes with offsets of 12 ft, 200 ft of guardrail

plus two 25-ft end treatments would be necessary to protect the

culvert. Culverts with offsets of 18, 24, or 30 ft require

150 ft of guardrail plus two 25 ftend treatments.

7) The severity indices and resulting accident costs were deter­

mined based on a survey sent to 15 personnel from the Texas

Transportation Institute, Texas State Department of Highways

and Rublic Transportation and the United States Department of

Transportation, Federal Highway Administration (~).

9

8) Severity indices for the three open-ended culvert sizes studied

on 2~:1 and 6:1 slopes were for perpendicular ditch crossings.

9) The encroachment data used in the study (~) limit the results

obtained to two-lane highways (using the total ADT) and to the

right side of divided highways using one-way ADT (half the total

ADT) .

10

III. GUIDELINES FOR EXTENDING OR UPGRADING

EXISTING UNPROTECTED CULVERTS

Historically, roadside barriers have been the primary safety

treatment for culverts. Only recently has there been the development

of other alternatives such as the grate safety treatment. Determination

of the type of treatment used (if any) has been based primarily on

engineering judgment and available highway funds. This is especially

true of low volume highways. Development of selection and priority

procedures based on cost-effectiveness has enabled highway officials to

make more objective decisions. It was through such procedures, described

in the Appendices, that the guidelines presented in this chapter were

developed.

Figures 3 through 8 contain guidelines for determining the most

cost-effective means of treating 36 in. diameter pipe, 4 ft x 6 ft single

box, and 4 ft x 6 ft double box culverts for various offset, traffic

volume, and side slope conditions. These figures indicate the circum­

stances where ranking factors exceed unity (i.e., where benefits exceed

costs), and which alternative has the highest ranking factor for a given

culvert size, ADT, side slope, and original culvert offset. Where ranking

factors for two alternatives were approximately the same for given

conditions, both treatments are shown as acceptable. The alternate

chosen would rest with the designer. Tables Cl through C6, Appendix C,

show the ranking factors calculated through application of the cost­

effectiveness model.

11

30 ~

t '-'

I-24 W DO NOTHING en

1L. 1L. 0 0 18 Z W

t---' 0: N W

> 12 :.J ::> U

...J <t Z -(!)

CE 0

0 0 750 1500 2250 3000 15000 20000-

AVERAGE DAILY TRAFFIC FIGURE 3. WARRANTS FOR EXTENDING OR UPGRADING A 36-INCH PIPE CULVERT ON A 2~:1 SLOPE

30 ~

~ .......,

r-24 W en DO NOTHING

l..L. l..L. 0

Cl 18 Z W

t---I 0: w w

:J 12

::> U

...J <1 Z -(!)

0: 0

o ~-----+----~~~--~~~~--~--~~--~~--~~~~~~ 15000 20000 o 750 1500 2250 3000

AVERAGE DAILY TRAFFIC FIGURE 4. l4ARRANTS FOR EXTENDING OR UPGRADING A 36-INCH PIPE CULVERT ON A 6:'- SLOPE

30 ,........

t '-'

..... 24 W en

DO LL LL NOTHING 0 0 18 Z W

t-~ 0::: .,J::::o W

>- 12 :.J :::> (J

--1 <t Z -(!)

a: 0

0 0 750 1500 2250 3000 ' 15000 20000

AVERAGE DAILY TRAFFIC FIGURE 5. WARRANTS FOR EXTENDING OR UPGRADING A 41 X 61 SINGLE BOX CULVERT ON A 2~:1 SLOPE

30 ~

t-= I.J... '-'

..... 24 W

(J) lJ... DO NOTHING I.J... 0 0 18·· Z W

I-..... 0::: U1 W

> 12 :.J ::> U ....J <t Z -(!)

a:: 0

'0 0 750, 1500 2250 3000 15000 20000

AVERAGE DAILY TRAFFIC FIGURE 6. WARRANTS FOR EXTENDING OR UPGRADING A 41 X 61 SINGLE BOX CULVERT ON A 6:1 SLOPE

30 ,......

t '-'

I-24 W

(f) DO LL LL NOTHING 0

0 18 Z W

I---' cr: 0"1 W

:J 12

::> U

...J <l Z -(!) CE 0 I 0 ~I--~--~--~~~~~~--~--~--~~~~--~~~--~~~

o 750 1500 2250 3000 15000 20000-

AVERAGE DAILY TRAFFIC

FIGURE 7. WARRANTS FOR EXTENDING OR UPGRADING A 41 X 61 MULTI-BOX (2) CULVERT ON A 2~:1 SLOPE

30 ,..... t-= IJ... '-'

r-24 W

en DO NOTHING IJ... IJ... 0 Cl 18 Z W

t---' '0:: --...,J W

?j 12

:J U

...J <1 Z -(!)

0: 0

o ~-----+----~~~--~~~~--~--~~--~~--~~~~~~ o 750 1500 2250 3000 15000 20000·

AVERAGE DAILY TRAFFIC FIGURE 8. WARRANTS FOR EXTENDING OR UPGRADING A 4' X 6' MULTI-BOX (2) CULVERT ON A 6:1 SLOPE

To use the figures:

1) Select the figure with the appropriate culvert size and slope.

2) Enter that figure with the proper ADT and culvert end offset.

3) Determine the appropriate treatment.

Note that these figures consider only the hazards of the slope, culvert

and ditch. Other hazards near or around the culvert may warrant other

types of safety treatment based on current AASHTO guidelines (1). The

information presented in these figures should be used in conjunction

with sound evaluation of the facts and engineering judgment.

To more precisely define the conditions where treatment is cost­

effective, the ranking factor data were processed one further step.

Table 1 shows interpolated values of ADT for ranking factors of 1.0.

Figure 9 shows sample calculations for the ADT interpolation.

The interpolated ADT values shown in Table 1 were plotted versus

offset distance as shown in Figures 10 and 11 for steep and flat slopes,

respectively. The curves represent a ranking factor (i.e., benefit/

cost ratio) of 1.0; thus the curves define the boundary conditions where

treatment becomes cost-effective.

These curves may be used directly to develop design guidelines for

upgrading existing facilities. Although new location projects would

involve the added cost of about 48 ft of culvert (under travel lane and

shoulder to provide 12-ft offset) construction, it may be rationalized

that larger projects usually result in lower unit prices and thus the

curves are a good starting point for developing design guidelines for

routes on new locations.

Figures 12 through 18 illustrate the potential for developing design

guidelines for these curves. Once a set of guidelines has been formulated,

18

Table 1. Interpolated AOT Volumes for Ranking Factor = 1.0

A 0 T

Culvert Size Side Slope A = 12' A = 18' A = 24'

36 11 dia. 2~:1 1110 (E)* 2020 (E) 1900

36 11 dia. 6:1 1310 (E) 1980 (E) **

1-4'x6' 2~:1 1130 (G) 1270 (G) 1300

1-4'x6' 6:1 1600 (E) 2090 (E) 2850***

2-4'x6' 2~: 1 800 (G) 880 (G) 990

2-4'x6' 6:1 1350 (E) 1600 (E) 2000

*Parenthesis include treatment, i.e., (E) = extend, (G) = grate, that becomes cost effective at lowest volume.

**RF = 1.0 for AOT = 15,000 or less; assume RF = 1.0 for A = 23' for 3000<AOT<15,000.

(G)

(ON)

(G)

(E)

(E)

(E)

***RF = 1.0 appears to level off at a slightly larger offset than 24 ft for ADT's up to 15,000.

19

l­lL..

... I­w (/) lL.. lL.. o

24

18 .- .............. --- •

2 --.. ----......... -...... -.-.-....... , . •

1 0.88 I I I

. I I I I

.... _---11.11

1.15

1.75

3000

ADT

Example: Single 41 x 61 box culvert, 6:1 slope; extension is the most cost effective solution for each set of traffic volumes and offsets.

Sample calculation: RF2 - 1.0

Interpolated ADTRF = 1.0 = ADT2 - (ADT2 - ADT1) ( RF2 - RF1

At offset = 121

Interpolated ADTRF = 1.0 = 2250 - (2250 - 1500)((1.75 - 1.0)/1.75 - 0.88))

= 2250 - 750 (0.75/0.87)

= 2250 - 650

Interpolated ADTRF = 1.0 = 1600

'FIGURE 9. . SAMPLE ADT INTERPOLATION FOR UNITY RANKING FACTOR

20

I

24

:: -I-l&J U) LL..

18 u.. 0

I-0:

N LLI ..... ~

V Ff36" dia. RF = 1.0

2-4 1 x6 1 MBC ~ 1-4 1 x6 1 SBC I RF = 1.DC-..

RF = 1.0 .; RF<l RF>l -. ~<l /. --RF<l

~>1 RF>l ,

•

::l 12 u .-

...J .. c:r: Z § 0: 0 6

2~:1 Slo~e

o 500 1000 1500 2000 2500 3000

INTERPOLATED AVERAGE DAILY TRAFFIC VOLUMES FOR RANKING FACTOR = 1.0

FIGURE 1 O. COST-EFFECTIVENESS CURVES 'FOR TYPICAL cut VERT ENDS ON 2~! 1 SLOPES

24

:: .. I-l&J U) lI-

18 LL 0 2-4'x6 1

' r~BC t- 'RF = 1.0 a:

N LaJ N ~

::> 12 (.)

..J " <t 36"dia. Z RF = 1.0 S 0:: 0, 6

6:1 Slope

o 500 1000 1500 , ,2000 2500 3000

INTERPOLATED AVERAGE DAILY TRAFFIC VOLUMES FOR RANKING FACTOR = 1.0

FIGURE 11 • COST-EFFECTIVENESS 'CURVES-rOR-TYPICAL--CULVERTS ON' 6: 1 SLOPES

c •

I-I&J en IL. &L 0 l-

N G: III w

~ :) U

i IE 0

12

" dia. RF = 1.0

6

6:1 Slope

o~--------~----------~----------~--------~----------~----------~------~ 500 1000 1500 2000 2500 3000

INTERPOLATED AVERAGE DAILY TRAFFIC VOLUMES FOR RANKING FACTOR = 1.0

FIGURE 12. POSSIBLE DESIGN GUIDELINES FOR TYPICAL CULVERTS ON 6:1 SLOPES

C •

t-III en IL &L 0 ....

N G: &II ~

~ :) U

i ii: 0

24

18

12

36" dia. RF = 1.0

6

6:1 Slope

o~--------~----------~--------~----------~--------~~--------~------~ ~OO 1000 1500 2000 2500 3000

INTERPOLATED AVERAGE DAILY TRAFFIC VOLUMES FOR RANKING FACTOR = 1.0 FIGURE 13. POSSIBLE DESIGN GUIDELINES FOR TYPICAL CULVERTS ON 6:1 SLOPES

AND SMALL (36" DIA.) CULVERTS ON STEEP SLOPES

C • t-

III en IL. II. 0 ....

N~ (.J1111 ~ :,) U

I iE 0

24

18 2-4 x6 1 MBC

RF = 1.0

12

6

6:1 Slope·

o~--------~----------~----------~--------~----------~----------~------~ 500 .000 1500 2000 2500 3000

INTERPOLATED AVERAGE DAILY TRAFFIC VOLUMES FOR RANKING FACTOR = 1.0

FIGURE 14. POSSIBLE DESIGN GUIDELINES FOR TYPICAL CULVERTS ON 6:1 SLOPES AND S~1ALL (36 11 DIA. ) CULVERTS ON STEEP SLOPES

- ----~---~. ------- - -.-- -- ----...- .. -.. - ------ --- -- --.-----

24

C .. ~

! 18 II.

0 l-

N ~ 0'1 1&1

~ :)

12 U

I 36" dia. RF = 1.0

-a: 0 6

6:1 Slope

o 500 1000 1500 2000 2500 3000

INTERPOLATED AVERAGE DAILY TRAFFIC VOLUMES FOR RANKING FACTOR = 1.0

FIGURE 15. POSSIBLE DESIGN GUIDELINES FOR TYPICAL CULVERTS ON 6:1 SLOPES

N .......

t­IE 1&1

~

1:"41x6 1 SBe RF = 1.0

36" dia. RF = 1.0

B 12~----~--~--~--~--+-~~----~----------4---------~~---------r------~

I G:. o 6~--------~----~----+----------+----------~--------~r---------~------~

2~:1 Slope

o 500 1000 1500 2000 2500 3000

INTERPOLATED AVERAGE DAILY TRAFFIC VOLUMES FOR RANKING FACTOR = 1.0

FIGURE 16. POSSIBLE DESIGN GUIDELINES FOR TYPICAL CULVERT ENDS ON STEEP SLOPES

36/1 dia. RF = 1.0

C 1-4 1 x6 1 SBC • RF = 1.0 f-

III (I) I&.

~ N

t-oo ~

&II

3 ::» 12 U

I -D:. 0 6

2~:1 Slo12e

O ~--------~----------~--------~~--------~--------~----------3000~------~ . 500 1000 1500 2000 2500

INTERPOLATED AVERAGE DAILY TRAFFIC VOLUMES FOR RANKING FACTOR = 1.0

FIGURE 17. POSSIBLE DESIGN GUIDELINES FOR TYPICAL CULVERT ENDS ON STEEP SLOPES

.-----.'~--,

36 11 dia. 24 RF = 1.0

C 2-4.' x6' MBC RF = 1.0~ • ...

1&1 (I)

"- 18 '~

... N IE ~ III

~ :)

12 U

i -0:. 0 6

2~:1 Slope

o 500 1000 1500 2000 2500 3000

INTERPOLATED AVERAGE DAILY TRAFFIC VOLUMES FOR RANKING FACTOR = 1.0

FIGURE 18. POSSIBLE DESIGN GUIDELINES FOR ALL CULVERT ENDS ON STEEP SLOPES

Figures 3 through 8 provide the necessary information for selecting the

treatment means. Example design guidelines are as follows:

1. For flat (6:1 or flatter) slopes and culvert sizes ranging

from 36 in. diameter pipe to double 4 ft x 6 ft boxes:

a. Where traffic is 1300 ADT or less and offset is 12 ft or

more, treatment is not cost-effective, as shown in

Figure 12; or,

b. Where traffic is 1500 or less and offset is 16 ft or more,

treatment is not cost-effective as shown in Figure 13

(36 in. diameter pipe on steep slopes also fit the same

criteria); or,

c. Where traffic is 1750 or less and offset is 20 ft or more,

treatment is not cost-effective as shown in Figure 14 (36 in.

diameter pipe on steep slopes also fit the same criteria); or

d. The IIdo-nothing" area could be defined to be variable with

traffic and offset as shown in Figure 15.

2. For steep (steeper than 6:1) slopes:

a. Where traffic volumes are 800 ADT or less, double 4 ft x

6 ft boxes and smaller size culvert ends with 12 ft or more

offset cannot be cost-effectively treated as shown in

Figure 16; or,

b. Where traffic volumes are 1100 or less and offset is 12 ft

or more, .single 4 ft x 6 ft and smaller size culvert ends

cannot be cost-effectively treated as shown in Figure 17.

These curves, particularly for steep slopes, could be further

developed by estimating additional unity ranking factor curves for

various culvert end areas as shown in Figure 18. Although resultant

30

design guidelines would be more difficult to use, a designer could enter

the resultant figure with a design traffic volume and culvert size and

determine the cost-effective offset.

In summary, the cost-effectiveness approach can be used to determine

appropriate design guidelines which identify conditions meriting treat­

ment plus identifying the most cost-effective alternative treatment.

31

IV. CONCLUSIONS AND RECOMMENDATIONS

1. Unprotected culvert ends located 27 ft or more from the pavement

edge cannot be cost-effectively extended to 30 ft or safety treated

for the volumes, hazard size, and slopes considered. Although not

specifically identified in this study, there may be combinations of

culvert size, slope rate, and traffic volume where an existing culvert

may be cost-effectively extended from 27 ft to more than 30 ft from

pavement edge.

2. AASHTO guidelines (1) suggest that steep (1:1 or steeper) drop-offs,

with or without permanent bodies of water, warrant protection only

if the drop-off is greater than 2 ft in depth. In this regard,

small (e.g., 18- or 24-in. diameter pipes) culverts with heights of

2 ft or less should not be considered as severe as larger culverts.

For these installations, ends should be sloped, preferably to match

side slopes, stabilized with flush riprap if necessary, and the

surrounding area should be smoothly contoured to decrease potential

impact severity and improve crashworthiness.

3. The provision of flat (6:1 or flatter) slopes allows for possible

driver action to avoid culvert-end collisions. Comparisons of

Figure 3 with Figure 4, Figure 5 with Figure 6, and Figure 7 with

Figure 8 reveal the impact of steep versus flat slopes in identifying

traffic and offset conditions which merit treatment of culvert ends.

32

4. Figures 3 through 8 identify cost-effective treatments for various

culvert conditions. The following general conclusions may be made

regarding particular treatment methods:

(a) For both flat and relatively steep side slopes, leaving the

culvert unprotected was the most cost-effective alternative

for traffic volumes less than 750 and culvert offset distances

greater than 12 ft.

(b) When culvert extension is cost-effective, it is desirable that

the culvert be extended 30 ft or more from the roadside. In

general, it was found that when safety treatment is warranted,

culvert extension is ~ cost-effective method -- although not

always the most cost-effective. However, special circumstances

not considered in this study, such as where needed right-of-way

is unavailable or costly, may preclude culvert extension.

(c) Grates for relatively flat sloped culvert ends were not found

to be cost-effective due to the large grate area and resultant

high cost. For steep slopes, however, grates were found either

to be competitive with culvert extension or clearly the most

cost-effective alternative as shown in Figures 3, 5, and 7.

Where possible, standardization of grate shape and structural

design may be expected to reduce "in-place ll costs and further

enhance its attractiveness as a safety treatment. Simple, shop­

fabricated grates designed for heavy (4500 lbs) passenger car

loading have demonstrated field performance, both from hydraulic

and impact standpoints. Reportedly, such a design has been

accidently impacted by a loaded truck with successful results

although grate deformation did occur.

33

(d) For the traffic volumes, slopes, and hazard sizes and locations

studied, guardrail protection was found to be ~ cost-effective

safety treatment only for the double box culvert and moderate

traffic volumes (greater than 2000 ADT) and the single box

culvert and high traffic volumes (greater than 20,000 ADT).

However, even for these culvert sizes and traffic volumes,

guardrail protection was not found to be the most cost-effective

alternative. Generally, guardrail protection appears to be a

more competitive alternative as the slope becomes steeper and

as the hazard size increases. In this regard, for culverts

larger than the double 4 ft x 6 ft considered in this study,

shielding by guardrail might be the most cost-effective solution.

5. Figures 10 and 11 may be used to develop design guidelines for new

location or upgrading existing facilities as exemplified in Figures 12

through 18. When such guidelines are combined with the information

regarding the most effective means of treatment as shown in Figures 3

through 8, a comprehensive, sound design policy is possible.

6. Other observations and conclusions can be made from this study if the

information presented in Figures 3 through 10 and Appendices A, B,

and C is used in conjunction with cost information available to the

various highway departments or agencies. These conclusions mayor

may not occur with those presented in this report.

34

v. FUTURE CONSIDERATIONS

In view of the research findings, the authors suggest the following

items be considered in future studies:

1) apply the cost-effectiveness model to

different culvert designs, slope conditions, and higher

traffic volumes;

2) refine the model to include hazards beyond the 30 ft clear

distance for fill sections with slopes steeper than 6:1;

3) develop a computer program with simple input data such as

culvert size and type, fill section slope, culvert end offset,

safety treatment, costs and restrictions (e.g., in some cases

extending to 30 ft is not possible), traffic volume, etc., to

provide more flexibility in design alternatives and to reduce

the computations required. and

4) incorporate encroachment data for low volume roads as they

become ava-; lab le.

35

APPENDICES

36

APPENDIX A A DISCUSSION OF THE COST-EFFECTIVENESS MODEL

The cost-effectiveness model used in this study calculates the

present value of each alternative over a given period of time, taking

into account the initial costs, maintenance costs, and accident costs.

The model can be expressed by the equation:

where:

CT = total present worth associated with the alternative (present dollar),

CI = initial cost of the alternative (present dollar),

CD = average damage cost per accident incurred to the alternative (present dollar),

CM = average maintenance cost per year for the alternative (present dollar),

COVD = average occupant injury and vehicle damage cost per accident (present dollar),

Cs = estimated salvage value of the alternative (future dollar),

CF = collision frequency (accidents per year),

KT,KJ = economic factors for some current interest rate.

The model is structured around an accident prediction technique used

to estimate the frequency at which a roadside hazard will be struck

over a given period of time. This is introduced into the model by

Al

the variable CF• Mathematically, the collision frequency is given

by the expression:

C = EF [(L + 62.9) • P(Y~A) + 5.14 F 10,560

(A2) where:

A = distance from edge of the traveled way to the hazard (offset),

L = hazard length (dimension parallel to the traveled way),

W = hazard width (dimension perpendicular to the traveled way),

EF = encroachment frequency (encroachments per mile per year),

these values are taken from the literature (~),

Y = the lateral displacement in feet, of the encroaching vehicle, measured from the edge of the traveled way to the longitudinal face of the hazard, and

p[Y~ •• ]= probability of a vehicle lateral displacement greater than some value. The values are taken from the literature (~).

Equation (A2) may be implemented directly into Equation (AI),

however, it should be noted that computation of the collision frequency

for multiple objects requires special procedures. Reference should

be made to the literature (1) for illustrations of these procedures.

To calculate the collision frequencies for the hazards in the

alternatives considered in this study, it was necessary to make three

idealizations. These are shown in Figures AI, A2, and A3. Note that

these hazard zones apply to both 2~:1 and 6:1 slopes.

A2

* ~ a.. 0 w

.... .r; .2 u ... ~o-0"0 Q; c: > a c: _

LLI .... cu ... > u-o :::J

0.0 E

30'

Ditch Hazard Lc Hazard

y ~Iope Hazard

"* Edge of Shoulder

"*"* Edge of Pavement

FIGURE AI. HAZARD ENVELOPE FOR AN UNPROTECTED CULVERT AND DITCH A3

Traveled Way

(I) -&: QJ

E -L.. 0 -2 CIJ

~ CIJ 0."0 o &: Q;LLJ >"0 &: &:

LLJ 0 --o .-o 0 a. L..

E 'E o ::::J

C)

Cl.. o LLJ

T 251 End

• ·Treatment

Ditch Hazard

ISO', When offset is· 18, 24, or 30 ft.

200' When offset is 121.

NOTE: GUardrail is a non-blocked 12 GA. W- beam rail on a 7" diameter timber ·post, @ 6'-3" spacing. End treatment is GEET 1 by AASHTO guide lines ( I )

FIGURE A2. HAZARD ENVELOPE FOR GUARDRAIL PROTECTED CULVERT A4

Cl. en o ~ w

Q,J 0-o "Q),c > 0 c .~ wo ...... u 0 0 .... 0-E

30'-----------------------~·1

Offs et ---t~-:::::"-:::::"'-'-_--+-_-r~L--,-I I I I I I

I Lc

Ditch Hazard

__ I ---- I ----~~--------------~~~--~

Io4--Wc~

/- Slope Hazard

• NOTE: Culvert is assumed part of slope

FIGURE A3. HAZARD ENVELOPE FOR GRATE PROTECTED CULVERT !t'

AS

Table Al contains a summary of the variables that would be

substituted into Equation (A2) to obtain CF for the various hazards_

It should be noted for hazards located both inside and outside the

30 ft. zone, that only the length and width inside this zone is

considered when calculating CF-

As stated in Chapter II, it was assumed that no vehicle redirec­

tion will occur on 2~:1 slopes. Since the model assumes a chance of

redirection in the zone from the edge of the traveled way (EOTW) and

the lateral face of the hazard, certain special procedures must be

followed. The basic procedure is to project all hazards to the edge

of the shoulder at an 110 angle. The length used in Equation (A2)

would be the projected length along the edge of the shoulder. These

variable values are also shown in Table AI.

To obtain the average occupant injury and vehicle damage cost

per accident (COVD )' the criteria in Table A2 was used (!). Severity

indices were assigned to each hazard based on a survey sent to fifteen

personnel from the Texas Transportation Institute, Texas State Department

of Highways and Public Transportation and the United States Department

of Transportation, Federal Highway Administration (~). Each person

was asked to evaluate the relative severity of each hazard considered

in the study based on the criteria in Table A2. The averages of the

responses received were then assigned to each hazard to obtain COVO .

See Appendix B for particular values of the severity index and COVD .

A6

TABLE AI. VALUES FOR CALCULATING THE COLLISION FREQUENCY (CF)

Variables for Calculating CF Alternative Description

Al L2 W2 with Hazards

Unprotected Cu1vert3 and Ditch on 2~:1 Slope:

1) Culvert 8 ft. LC + 5.14 Wc 0

2) Ditch 8 ft. 123 - 5.14(Wc + Offset) 0

3) Slope 10 ft. (15 or -35 ft.) - LC + 5.14(Offset) 1 ft.

r----------_-------------------------------Unprotected Cu1vert 3 and Ditch on 6:1 Slope:

1) Cu1 vert 2) Ditch 3) Slope

1----------- ----ISO ft. of Guardrail Protection on Any SlopeS:

1) Approach guardrail and end treatment

2) Departure guardrail and end treatment

Offset

Offset + Wc + 6 ft. __ 4

LC 1 ft.

__ 4

Wc 24 ft. - (Offset + WC)

__ 4

----------------------------

14 ft.

11 ft.

175 ft.

-6 ft.

1 ft. 1 ft.

--------------- ---------------_._---- -------200 ft. of Guardrail Protection on Any SlopeS:

1) Approach guardrail and end treatment 2) Departure guardrail and end treatment

14 ft.

12 ft.

175 ft.

44 ft. 1 ft. 1 ft.

---------------------- ------------f---------Grate Protection6 7 on 2~:1 Slope

1) Ditch 2) Slope

8 ft.

10 ft. LD + 154 ft. - 5.14(Offset + WC)

(-16 or -66 ft.) - LD + 5.14(Offset + Wc

o 1 ft.

1--------------------------------------- ---6 7

Grate Protection on 6:1 Slope

1) Ditch Offset + Wc 30 ft. - (Offset + Wc) 2) Slope

__ 4 __ 4

IFor values of A greater than 30 ft., cF = O. 20n1y the length and width within a 30 ft. clear zone is considered. 3Refer to Figure AI. 4This is done by first finding CF for the slope protected by either 150 or 200 ft. of guardrail. Next, subtract the CF for the culvert and the CF for the ditch from this value to obtain the CF for a 6:1 slope. 5Refer to Figure A2. 6Refer to Fig~re A3. 7Since the grate is assumed to be traversable, it is also assumed to be part of the slope, so that there are only two hazards, namely, the ditch and the slope.

TABLE A2. SEVERITY INDEX AND ACCIDENT COST

Severity % PDO % Injury % Fatal Total Accident Index Accidents Accidents Accidents Cost (COVD )

0 100 0 0 $ 700

1 85 15 0 2,095

2 70 30 0 3,490 3 55 45 0 4,885

4 40 59 1 8.180 5 30 65 5 16,710

6 20 68 12 30,940

7 10 60 30 66,070 8 0 40 60 124,000 9 0 21 79 160,000

10 0 5 95 190,000

A8

APPENDIX B APPLICATION OF MODEL

Input Data

This appendix presents the particular values assigned to each

variable in Equation (AI). Values of CF are not given since the tech­

nique used to calculate these values is presented in Appendix A. A

summary of all costs is given by each alternative. A constant value

for KT = 8.514 is used for all alternatives based on a 10% rate of

return over a 20 -year term.

Alternative I - The Unprotected Culvert

A) Assumptions

B)

where:

1) C = 0 I (no initial costs)

2) C = 0 D (no damage to culvert upon impact)

3) C = 0 M (no maintenance costs)

4) C = 0 S (no salvage value after 20 years)

Revised form of equation (AI):

CT = 8.514 [( CFCOVD)SLOPE + (CFCOVD) CULVERT + (CFCOVD ) DITCH J (Bl)

(CFCOVn)SLOPE = collision frequency times the occupant and vehicle damage caused by the slope;

(CFCOVD}CULVERT = collision frequency times the occupant and vehicle damage caused by the culvert; and

B1

(CFCOVD)DITCH = collision frequency times the occupant and vehicle damage caused by the ditch.

C) Summary of other costs

1) See Table B1.

TABLE B1. SEVERITY INDICES AND ACCIDENT COSTS FOR THE UNPROTECTED CULVERT*

Culvert Type (COVD)SLOPE

36 in. pipe on 2~:1 slope $5900 (3.3)**

36 in. pipe on 6:1 slope $2500 (1.3)

41 x 61 single box on 2~:1 slope $5900 (3.3)

41 x 6 1 single box on 6:1 slope $2500 (1.3)

41 x 61 multi-box on 2~:1 slope $5900 (3.3)

41 x 61 multi-box on 6:1 slope $2500 (1.3)

*Based on the criteria in Table A2. **Severity index in parenthesis.

(COVD ) CULVERT

$16,710 (5.0)

$16,710 (5.0)

$28,100 (5.8)

$28,100 (5.8)

$42,500 (6.3)

$42,500 (6.3)

Alternative II - Extending Existing Culvert to 30 Ft

A) Assumptions

1) Wing wall must be replaced.

B2

(COVD)DITCH

$7400 (3.8)

$6000 (3.4)

$10,000 (4.2)

$6400 (3.5)

$7400 (3.8)

$4900 (3.0)

2) Fill must be added for smooth transition between slopes.

B) Revised form of equation (AI):

(B2)

where:

CT30 = total cost of unprotected culvert with 30 ft. original offset

Cww = cost of wing wall

CEXT = cost of extending the culvert pipe or box; and

CFILL = cost of fill material.

c) Summary of other costs

1) See Tables B2, B3, and B4

TABLE B2. COST OF WING WALLS (CWW )

Culvert Type CWW for 2~: 1 Slope CWW for 6:1 Slope

36 in. pipe $260 $620

4' x 61 single box $460 $1100

41 x 6' multi-box $450 $1100

B3

TABLE B3. COST OF EXTENDING THE CULVERT PIPE OR BOX TO 30 FT FINAL OFFSET (CEXT )

Culvert Type

36 in. pipe on 2~:1 and 6:1 slopes*

41 x 61 single box on 2~:1 and 6:1 slopes**

41 x6 1 multi-box on 2~:1 and 6:1 slopes***

*Based on $25/ft. **Based on $95/ft.

***Based on $165/ft.

Original Offset 12 ft. 18 ft.

$450 $300

$1710 $1140

$2970 $1980

B4

24 ft.

$150

$570

$990

TABLE B4. COST OF FILL FOR EXTENDING THE CULVERT TO 30 FT FINAL OFFSET (C FILL )*

Original Offset

Culvert Type 12 ft. 18 ft.

36 in. pipe on 2~:1 slope $820 $1100

36 in. pipe on 6:1 slope $470 $520

41 x 61 single box on 2~:1 slope $900 $1200

41 x 61 single box on 6:1 slope $540 $550

41 x 61 multi- box on 2~:1 slope $930 $1200

41 x 6 l multi-box on 6:1 slope $550 $560

*Based on $2.35/yd. 3

B5

24 ft.

$1300

$570

$1300

$580

$1400

$580

Alternative III - Guardrail Protection

A) Assumptions

1) CI = (Length)($13/ft.)

2) Co = $225

3) COVO = $5900 (S.I. = 3.3)

4) CM = (Length)($1.50/ft.)

B) Revised form of equation (AI):

CT = CI + 8.514 f(co + COVO) (CF + CF ) + CM]·. (B3) L AP OP

where:

CI = total initial cost of barrier proper and end treatments ($3250 or $2600);

CD = damage cost to barrier proper and end treatments after a collision ($225);

Covo = occupant and vehicle damage cost caused by barrier proper and end treatments ($5900);

CM = total maintenance cost of barrier proper and end treatments ($375 or $300);

C = collision frequency for the approach guardrail and end treat-FAP ment; and

CF = collision frequency for the departure guardrail and end treat­BP mente

Alternative IV - Grate Protection

A) Assumptions

1) CD = 0 (no damage to grate upon impact)

B6

2) CM = $100

3) Cs = 0 (no salvage value after 20 years)

B) Revised form of equation (AI):

CT = C1 + 8.514 [ (CFCOVD) SLOPE + (CFCOVD)DITCH + CM] (B4)

where:

C) Summary of other costs

1) See Table Bl for (COVO)SLOPE and (COVO)OITCH·

2) See Table B5 for CI .

TABLE B5. INITIAL COST OF GRATE PROTECTION*

Culvert Type CI on 2~:1 Slope CI on 6:1 Slope

36 in. pipe $600 $6900

41 x 61 single box $1300 $13,800

41 x 6' multi-box $2000 $19,100

*Includes only the cost of the grate.

B7

Ranking Factor

The ranking factor is a ratio of the benefits received by using

a particular alternative to the costs incurred by the highway depart­

ment or agency associated with the installation of that alternative.

The following formula may be used for determining a ranking factor, R:

where:

CT = total cost associated with the unprotected culvert; H

(B5)

CT = total cost associated with the selected alternative; and I

CTO = total cost to the highway department or agency associated I with selected alternative.

To obtain CTO for each alternative simply substitute Cavo = 0 into I

equations (B1), (B2), (83), and (84). This will then give for the

unprotected culvert:

CTO = 0 I

extending to 30 ft.:

guardrail protection:

CTO = C1 + 8.514 [(CO)(CF + CF ) + CM] I AP OP

88

(B6)

(B7)

(B8)

and for grate protection:

(B9)

where all variables are as previously defined.

Tables B6, B7 and B8 list the direct costs for each alternative

based on equations (B7), (B8), and (B9).

TABLE B6. DIRECT COSTS FOR EXTENDING A CULVERT TO 30 FT FINAL OFFSET

Original Offset Culvert Type 12 ft. 18 ft.

36 in. pipe on 2~:1 slope $1500 $1700

36 in. pipe on 6:1 slope $1500 $1400

41 x 61 single box on 2~:1 slope $3100 $2800

41 x 61 single box on 6:1 slope $3400 $2800

41 x 61 multi-box on 2~:1 slope $4300 $3600

41 x 61 multi-box on 6:1 slope $4600 $3600

B9

24 ft.

$1700

$1300

$2400

$2300

$2800

$2600

TABLE B7. DIRECT COSTS FOR GUARDRAIL PROTECTION OF 36 IN. PIPE, 4 FT x 6 FT SINGLE BOX, AND 4FT x 6 FT MULTI-BOX (2)

CULVERTS ON 2~:1 AND 6:1 SLOPES

ADT OFFSET = 12 FT. OFFSET = 18.24 or 30 FT.

750 $6500 $5200

1500 $6600 $5300

2250 $6700 $5300

3000 $6700 $5400

15000 $6700 $5400

20000 $6900 $5500

TABLE Ba. DIRECT COSTS FOR GRATE PROTECTION

CTD for 2~:1 Slope CTD for 6:1 Slope Culvert Type I I

36 in. pipe $1500 $7700

41 x 6' single box $2100 $14,600

41 x 61 multi-box $2900 $20,000

B10

Using this infonnation, ranking factors were calculated for each

alternative. The alternative with the highest ranking factor is the

most desirable since it returns the largest benefits for the lowest

total direct costs. Ranking factors for leaving a culvert unprotected

is theoretically 1.0 since CT = CTand CTO = O. Thus alternatives H I I

with ranking factors less than 1.0 are undesirable since an unprotected

culvert has a higher ranking factor.

Figur-es 3 through 8 are based on the alternative with the highest

ranking factor. The unprotected culvert was assumed to have a ranking

of 1.0 since it was one of the alternatives considered.

B11

APPENDIX C SUPPORTING DATA

This appendix contains all the data necessary to obtain Figures

3 through 8. These data can also be used in conjunction with the

information presented in Appendices A and B to obtain new criteria

for different direct costs. See Appendix 0 for further discussion.

Tables C1 through C6 present the ranking factors for each alter­

native by each culvert design considered in the study. Tables C7

through C12 list the total costs for each alternative by each culvert

design. Tables C13 through C18 list the direct costs for extending

each of the culvert designs. Note that ranking factors, direct costs

and total costs are given in each table for extending culverts to 18,

24, and 30 ft. Although this study was concerned primarily with

extending to 30 ft, it may not be possible where there are limited

right of ways or other extenuating circumstances. Thus it may be

feasible to extend the culvert to 18 or 24 ft where other alternatives

are not possible. Again see Appendix 0 for further discussion.

C1

() N

F ui~ A .3t.> 1 i'·J.. U I hi'vii::.1 t:t< P 1 .... [ uN A 2-1/2. r u 1 SLLd-'t:

A=1L' t-=T. .4.=lti I-T.

Flj\jAL UrF~Ll 1\'='30 Fl.

u. £:.' j -0. 1 L ~) 0.':;0 -0 .9;";'

l~CO"O 1 .'4 ~ 0.7 C 1 .72 -0 .8 't

~ '. ,

.-.I~ 1 .4h 2.t.Jb -0 .ft.>

....:.uGu.lJ ...>. -, 7 £: • .3 3 4 .. ::)4 -0 .. t) C,

1~0Uv.U 3.(:L, £:'.40 4 .44 -0 .D I

LeVoU .... 1 -..I • I;';, ~"" '/0 C.!:=;4 -0 • 5.4

TABLE C1. RANKING FACTORS FOR A 36 INCH PIPE CULVERT ON A 2~:1 SLOPE

A=c4 f-1'.

A=.j.O Fl. A:...·.30 FT.

-0. L'q -0 .32

O.5£:: 0 .36

1 .2 1 0.98

1 • <;1 -{ I .bb

2 .03 1. . 11

3.20 2 .. 76

RANK 1 NG FAC TCr.tS FUR GUARDRI\. I L VS. UNP KOT f.:C TEO

F(Ji-:( A ::,6 IN. Dll\r"H~TLt~ PIPL UN 1-.2-1/2 TO 1 SLJPi~

AD T A =:.} 2'FT. A.. ==-1 8FT. A::,::?'4.FT . A =7:.: (jr or •

"7f>O .0 -c .. -/2- -0 • £.3 -0 .6:::'- - 1 · (;7

1500.0 -o.~) ( -0 .. b-' -0 .. -10 -1 ... 1 :~)

(J w 22~O • 0 -0 .. 38 -0 · t:2 -0 .~) 7 - 1 .-)

..... r •• 1

3000 • 0 -(J • IB -0 · :b -0 .. 4::". -. I • '".".J ,'- ....

IbOOO .. 0 -0 .. 1 7' -0 .. ::·.5 -0 .42 - 1 · ;~s

20000 .0 0 .. 14 -0 .. 1 1 -0 .20 - . 1 • .... :~ ti

TABLE Cl (CONTINUED). RANKING FACTORS FOR A 36 INCH PIPE CULVERT ON A 2~:1 SLOPE

rU\NKING fACTDhS FUP GR/\ll':: Pr~OlcCTION \IS. Ut\PRUTECTED

F {y~ A :) 6 It\l. D I At,i f: r f q PI f} L (i N A 2 - 1/ L: T u 1 SL OPE

AD -J A=-12FT. A= 1 eFT. A=2~FT. A ='3 OF T ..

"7 ~;o. 0 u.07 -0 .. 27 -0.19 -1. 00

1500.0 1.14 0.47 0_,62 -1.00

n ..p. ;';2~O.O 2- • 13 1 · IS 1 .36 -1.00

3000.0 J .. 19 1 • b8 2.17 -1.00

l::~oon.G 2~.~~H 1 · (A 2.23 -1.00

20000.0 if.92 3.ll? 3.4ts -:'1.00

TABLE C1 (CONTINUED). RANKING FACTORS FOR A 36 INCH PIPE CULVERT ON A 2~:1 SLOPE

n (J1

F U k J~. J tJ 1 h;. I) 1 ,1-\ i"i L I l. k f--' 1 f-J tUN A t: 1 U 1 !..J L G P t,

Uk 1 C 1 N A L. C 1- t,' ~; t~ -. J~.:". 1 L r·f. h:::' 1 L' t-J. A;:.: 1 L: r'l. A;;;;:,]b FT.

f,:":' 1 L f- I • A::..2 Lt I· T • A=...;.,G j-'I. A :..:..2. '" FT ..

-l.!.c.~:L -(j · (;-( 0. It -0 {;.. 7 . _.'

1 ~l:O • U i..i • <i t) o. b-{ 1 .. (:::(; -0. 1,)

1 · I 1 1 · -, :] 2. -; '" 0 .2-' • _'-.....J ""'C,, ::..,0 .. U

1 • t 4 £:: • be 3.::"0 0 .. 70

1 · LIS 2.. -r ~~ ...:) .. ~(" 0 .. -'3

...}.0 U 4. 1 -, /'" ,J.

.~ j;C .....;....;. 1 .40

TABLE C2. RANKING FACTORS FOR A 36 INCH PIPE CULVERT ON A 6:1 SLOPE

A::,',lb FT. A=-24 Fr ..

A =.:50 Fl. A=30 Fl.

-0 .. 2;':, -0.51

o .5·q· -(,) .o.£:

1 .;;'L 0 .43

2 .. 03 0 .~ 1

2.0S o .. ~.'f tJ

3.2b 1.70

RANKING FACTORS FUR GUAhDRAIL VS. UNPhOTECTfO

FOR A 3 bIN. D I AM ElL R ? j P L lJ hl A 6 T 11 1 SL G P [

ADT ;\ = 1 ~'FT • h=l 8Fl . A=2t.FT .. 1\ =-3 Oi= T •

750.0 -O.qs -1 • 00 -1 . 09 - 1 . 2 ~~

1500 .0 -O.b9 -1 · (,U -1 .. 1 L~ - I e, 42

() ;':'2 :;Q .0 -0. bS -1 · eo -1 r; I' - 1 () t . .::.. -~ . O'a

JOOO .0 -0. -79 -1 · co -1 • :)3 -. 1 .. ~:qj

15000 .0 -·0. -fP, -1 a, ct -1 .35 .....;1 . 72.3

2uOOO .u _.(j • 12. -1 .. LO -} o.4t -2. t ~

TABLE C2 (CONTINUED). RANKING FACTORS FOR A 36 INCH PIPE CULVERT ON A 6:1 SLOPE

· ~;;Ar'4r<.lNG F~.CTUF~~~ FU!~ GRATE PROTECTION VS. UNPf<UTECTED

F(i~{ l\ 36 IN. DIAt.J(CTFR PIPE UN A b TO 1 SLUPE

AUT A=12FT. A=lbFT. A=2!+FT. A=30FT.

{SO.O -0.7'1 -0. f6 -O.q? -1.00

1500.0 -(j.~b -0. II -O.B3 -1.00

n --..J ?2!:)O.O -(i.]K -0. t.B -0.75 -1., 00

~:iO 00.0 - (J. 17 -0.44 -0 • (::, 7' -1.00

15000.0 -(i. 16 -0. 4:-1- -0.66 -1.00

~~·OOOO .0 (). 1 -{ -0. £:"1 -0.5.:5 -1.00

TABLE C2 (CONTINUED). RANKING FACTORS FOR A 36 INCH PIPE CULVERT ON A 6:1 SLOPE

n co

Po. ~ 1 ~ r -, • /'. = 12 Fl. A=12 '-=1. A= 1 f, Fl. A=lb FT.

/,::.·1(, ~I. A =L, 4 FT. A:::. ':::·U t= 1 • /\.=30 FT.

f.,UI

- l.l • L. .:... -0 .,2;0 0 .. 2l..- -0 .. -I 1 0.07'

\} • tJ..:;, 0.40 1 .. b-' -0 .4~ 1 • 14-

1 . c'4 1 .. 0 ~j 2.76 -0 .. lS 2. 1 3

~ ..• ' u (; 1 .7::""· 4 .(;~ 0 .1 tJ .i.c'O

£- • lie 1 . L(; 4. 1:::- 0 .. 1 7 3 .. 2b

..).,...:. '4 2- .l';. t'.. l" .. 12 0 .6:::: 4.Y;';;

TABLE C3. RANKING FACTORS FOR A 41 X 6 1 SINGLE BOX CULVERT ON A 2~:1 SLOPE

A=24 Fl.

A ;;;..30 f -J •

0.03

I .07

2.02

,j.Ob

3 .. 14

4 .7~

RANK ING FACTuhS FrH< GUA.~DkA 1 L \is. UNfJr-:,uTLCll-.D

FO~~ A 4 X b FT. SINGLt:: BOX CULVEnT ari A 2-1/c TU 1 SLUPL

ADl A ='1 Lf T .. A:::1 PF--T. A =~2 4 F.T · f, =<5 Ot-= 1 ..

"/50.0 -0 .. !:>O -0. t:.! -0 .61 - 1 · r ~

\./1..)

1500.0 -O.Ul -0 • 03 -0.22 -:-1 .. 1 ",

n 22~~O.O 0.43 0 "to 0 .. I :-"\ -1

1.0 · · ;> 1

:)000.(; 0.01 0 .. 1:-6 0 .::..:,() - 1 · c·t";

150(j 0.0 G .. "}5 0 • f0 () • 5~: - 1 · 29

20000 .0 1 .64 1 · t~} 1 • () 0 - 1 • :~'}

TABLE C3 (CONTINUED). RANKING FACTORS FOR A 41 X 61 SINGLE BOX CULVERT ON A 2~:1 SLOPE

1-< AN KING F J\C ror~s F 01-< c;ru:.. TL IJI-Hl1 L CT ION VS.. UI'IPR OTEC TED

F l j r< A 4 X L> F T.. S r !\i GL C (", () X C lJ L V li=-< T D ~ A 2 -1 /2 TO 1 S LOP E

A()T .A. :::: 1 :::'.F"T., A=lP-FT. A=24FT. A=30F 1 •

-,~) G • 0 O.'~ 6 o. 15 0.15 -1.00

1500.0 l.~l 1 . 36 1 .30 -1.00

n C_'£.:"t)O.o ___ oj .. 2. t) 2.4::' 2 .. 37 -1.00 ....... 0

.JOOO.U Lt.7"1 3. b3 3.52 -1.00

1'-)000.0 Il • t: 2: :3. -(2 3.61 -1.00

;':0000.0 f.OI ~ .. ::A 5.36 -1.00

TABLE C3 (CONTINUED). RANKING FACTORS FOR A 41 X 61 SINGLE BOX CULVERT ON A 2~:1 SLOPE

U /" 1 (, I N A. L G t":' F :.... l_ I A~ 1 L Ft .. A.:;..·l£: Fl. A=lb Fl. A=c4 FT.

i, =-~ 4 Fr. A=-24 fT. A=-30 t-= 1 • A=~O t-=T.

h0J

-l·. '-I l' -(; • ~~ '-I -\..1 • 0b -0 .S7 -0.2.6 -O.4t.

ti.L 1 O.5C".: 0.86 -·0 . 14 0.4";- o .OI

Ci. f -, 1 .2. _., 1 • -f t- O .2 t- 1 . 1 r::: 0.57 " t::. . .L ~. 0 • (;

.;)0U0.U 1 .,:j ., 1 • '.:/ ~I L .t:Jy 0 .bb 1 .b':J 1 • 1 1

1 . qc. 2 .. O~ L- . '/e 0 .. -I ';;., 1 • 'J4 1 . It>

.1 3.~2 4 .~(; 1 .3b 3.vo 1 .Sb L-.• -.J ....., L:.U000.u

TABLE C4. RANKING FACTORS FOR A 41 X 61 SINGLE BOX CULVERT ON A 6:1 SLOPE

RANKll'-JG F AC TOI1.S r liFl CUA~D KA 1 L V S. UN P i;;OTL elE D

FOf-< A 4 X f. FT. S I NGLt:. tic/X CUL V:::RT (Jr-J A 6 lO ) 5L(JFlE

AD1 A::::} £.:'f T .. A:::.l eFT ..

750.0 -0.74 -0. [2 -0 • l)l)

1500 .. 0 --0 .. 4 7 -0 .. tA -0 • :)6

-(i.24 -0.4t.'.

0. (}2

l~OOO.O G.uS -0 .. ~l -(J • (:;:j

20(JOO.O u.41 -0 .. 04 -G.qu

TABLE C4 (CONTINUED). RANKING FACTORS FOR A 41 X 6' SINGLE BOX CULVERT ON A 6:1 SLOPE

RANKING Ft.CTU~S FOi~ ~1<A1E PRUTECTIDN \IS. UNPROTeCTED

FUR A 4 x 6 Fl. SINCLE AOX CULVERT ON A 6 TO 1 SLOPE

ADl A=12FT. A=18Fl. A=24FT. A=30FT.

750.0 -Ci.79 -O ... bb -0.92 -1 .. 00

1 t) 0 0 .. 0 -0.59 -0. -,2 -O.8~ -1.00

n 2;'->:')0.0 -0.40 -0. ~H -0.76 -1.00 ~ w

3000.0 -0.19 -0.45 -0.68 -1.00

1 ~) 00 (j .0 -0.17 -0. Ll4 -0.67 -1.00

2.0000.0 0.1::- -0 • ,~L:' -0.54 -1.00

TABLE C4 (CONTINUED). RANKING FACTORS FOR A 41 X 61 SINGLE BOX CULVERT ON A 6:1 SLOPE

A::.. 1 L t:': r • A=-le: FT. A=lb t-=T. A::.16 FT. A::-.24 FT ..

A =-£:.4 PI .. /-'=-::'0 Fl. A=-24 ~T. A=30 FT. A=-30 FT.

/-i LJ i

-0. ~) it -O.4t., 0.35 -0 .b() 0.41 O.~l

-G.Ve... o. 1 1 1 • -fO -u .20 1 .bL 2.03

v .. ~j::':, 0 • t~ £:. C .SS 0 . lb :::5. 1 £: j, .. 42

.j '.j (tV .. U V.0 J 1 • 1 -, 4.:.:lU 0 .50 4 .tJ~ 4 .. 93

1::;OL0.0 u. L~ 1 .2 I Lt .. ,~ 1 0 .. 6 1 4.6~ t>.05

i • ~-,L 2.0t; 0.49 1 .2.,:, b.bl 7.::)b

TABLE C5. RANKING FACTORS FOR A 4' X 6' MULTI-BOX (2) CULVERT ON A 2~:1 SLOPE

RANK ING FACTORS F OR GUARD F:':'A I L VS. UNPr:~OTECTLD

FOR A 4 X 6 FT. r..HJL 1 I-t:H))( CULV[~T ON A 2-1/2 TCJ 1 SLUP[

AOT A.::::.12FT. J\ = 1 6FT . A=24FT . A=:JOFT •

750 &0 -0.21 -0. 11 -0.2'/ -1 · {j ,: 1500.0 0.t>d u. 7b 0 4 f ... - 1 · 1 .. -' --

n 2£-.:50 .0 1 .26 1 • t.7 1 · 1 0 -] • c~ 1 J--1 (J1

3000 .0 .2.03· 2 · 41 1 • -/l., - 1 · C:. ;,

ItlOOO.O 2.09 ., c. 4t. 1 .8? - j · 2 ,:A

20000 .0 ..::. .. 1 () 3 · -('~ 2 · ~j ~~ - 1 • .j {J

TABLE C5 (CONTINUED). RANKING FACTORS FOR A 41 X 61 MULTI-BOX (2) CULVERT ON A 2~:1 SLOPE

F<I\hIKING Ff,:CTCRS fUt':: GRATe PR01[Cll(j~.J \15. UNPROTECTED

F Cl F< A 4- X 6 FT. r ... , U L T I -t3 U X C U L V L RT 0 N A 2 - 1 /2 TO 1 S LOP C

ADT A.:.:.·l~'FT. A=18FT. A=24FT. A=30FT.

-(50.0 O.b7 0 .. 71 0.4B -1.00

It.>GO.O C:.75 t::.42 1 .96 -1.00

n 22!::,O .0 ['.4(3 4 • DO 3.33 -1.00 ........ Q)

3000.0 t .. 3S 5./2 4.81 -1.00

l~OOO.O C.~O t) .. t.!:> 4.92 -1.00

£~oooo.o '1.36 8.4b 7.20 -1.00

TABLE C5(CONTINUED). RANKING FACTORS FOR A 41 X 51 MULTI-BOX (2) CULVERT ON A 2~:1 SLOPE

t-U~ A Li X L Fl. j·jUL Il-ldJX LULVlk" eN A b 10 1 SLUPt.

1-\ =- 12FT. ,4,=-1.2 FT. A:::. 1 b FT. A=lb FT. A =·24 FT.

~ 1 i-J 1\ L U t- t~ ::-- r.:1 A=-:50 FT. A=L:4 Fl. A=30 FT. A=30 ~l.

l'.U 1

I ::0 .. v -0.0'-. j • 1 1 -0 .41 -o.ot.> -0.23

1:"00.0 o .L~: l.~~ 0.1-'

i • £. C. 0.71 1.76 1 .. 24

1 ,,~, t: 1.30 2.01

1 ::, l; L lj t V .:..- • u .... 1 .3'-l 2.7b 2.07

4 .. 04· 4.2..:)

TABLE C6. RANKING FACTORS FOR A 41 X 61 MULTI-BOX (2) CULVERT ON A 6:1 SLOPE

f~ANKjl'Jl; Ft,CTOk~ FCi{ (,uARDh:AIL v:.:.. lnJP;""'OTE..CTCD

FCJF< A L~ X fJ ~·T. I"IULTI-HOX CULVI:.I~T ON I, 6 Tn 1 ~)L..UIJE

ADT A =1 ?F-' · A=l EFT · A=24FT .. A=:::,(lF T6'

7~O.O -0. 44- -0 · !..b -0. (~13 - 1 . ."~ ,") L. ~~

1 500 • 0 o. 1 2 -0 · l..i -() .. b :-} -1 .. if c~

n I-' 22S0 .0 u.t) 1 () · 2()- -0 e· ~:) \) -1 a· t, 1 CO

3000.0 1 • 14 0 · 66 -0. -';[ -~

~, -' -} .. bU

1 5000 .0 1 · 1 ,) 0 t-9 --0 . :1.:- - 1 c-:. • .. t...) .... J

20000.0 1 .97 1 · :'2 -0 .Ob -;,.:. 1 ;~.

TABLE C6 (CONTINUED). RANKING FACTORS FOR A 41 X 6 1 MULTI-BOX (2) CULVERT ON A 6:1 SLOPE

FUR /\ 4 X 6 F T .. ~Jl UL 1 I - H [) X C U L V F R TON A 6 TO 1 S LOP F

'j \' t., AD r A:::.lc-F I . A ='1 ~Fr. A=-24FT. A=30FT.

750.0 -0.7''J -0. t~3 -0.90 -1.00

lS(;O.O -0. :i0 -0 .. (6 -0.80 -1.00

() ......

2;~ ::,0 .0 -0.27 -0. to -0.70 -1 .00 I..D

;:)0 (j 0 • (} -f) • G3 -0. ~j -0 .60 -1.00

It-}OOO.O -(J.Ol -0. -- '> -'"'-- -0.5':1 -1 ~OO

20000.0 0 .. ~j~") -0 .. 05 -0.44 -1.00

TABLE C6 (CONTINUED). RANKING FACTORS FOR A 41 X 61 MULTI-BOX (2) CULVERT ON A 6:1 SLOPE

TnT f\L C(j~: T nF A r·, UhH:':UT C.C lCU CULVt:"F<T

~ U F< A :3 v I i',j.. D I .A. r.'! L T I::: ~< P I r.J 1-:- U r", A ;: -1 / c: TO 1 5 L UP E

AD 'r ,/)' ::: 1 2fT. A:::.IAFT. A==-24FT. A=3 OF T.

7C::,O .0 3400.GO 2"~OO. 00 2400.00 1 300. 00

1500.0 b 10 (} .. 00 5100.GO 4900.0'0 250 0.00

n N 22t:)O.O (jDOO.C0 0

7400. 00 7200.00 37'00. 00

3000.0 1:J200 .. 00 lOOOO.Ou 9600.00 S 00 0.00

1~50GO.O 1.5400.GO 10100 • 00 9AOO.00 ~")lOO.OO

20000.0 IbvOO.OO 14000. (/0 13600.00 7'100.00

TABLE C7. TOTAL COST DATA FOR A 36 INCH PIPE CULVERT ON A 2~:1 SLOPE

() N ..........

lu·.I,L l.L.~.i rUlo( LXfLNUING A CULVt:..Rl

A:..··li.:.. Fl. A=18 FT.

f l1';I'.L LiFt- ~d:. I f,:": i t, r I • J\=24 1-1. A=30 FT.

f-.Ul

~j £:. (j l) .. C 0 ~i~)O(). U(I :'::bOO.{)O ..::j 00 .00 ~.YOO.OO

!J tCl;.U(., c..v 0 (}. 0 (I 't 100.00 GO 00.00 4200.0,)

cl00.ll () (-:'£:00.00 t.30G.OO L2GO .00 tAOO.OO

10Cvv.vv 10-{00.00 Lt:.CU.00 10 -lOO .. 0 0 biOO.OO

10LOu.l;( .. 1 C';;lOG.OO bt·('O .. DU 1 GSOO .00 6tjOO .. GO

1 '" ( 0 \., • (, \.J lLtLVO.UO aeOO.VO l'-l-t.vO.OU t;;l 00. () (}

TABLE C7 (CONTINUED). TOTAL COST DATA FOR A 36 INCH PIPE CULVERT ON A 2~:1 SLOPE

A=24 r1.

A=30 f-l.

3000.00

4~OO.OO

t:,500 .. 0 0

t--"OO .00

ob00.00

bbOO .00

lOT tI.L COS 1 (JF A GUtd~Dr<A IL PRdTt- CTt::::D C l.LVC.f<T

ADT A :::::12f-1 .. A=lbFT · A=24FT. A=~~(jf"T.-

7!::.O. G eSOG.oo 6900. llJ 6900.00 f (),! O. .~") {j

1bOO.0 lO~OO.OO 6600 · LO b600.f'IO i~, t.,O (). 00

n ~2~,O.O 12400.00 10200 N • O(i 1 o;~ 00« 0 {) 1020 l,. GO

N

3000 .0 14400.00 1 1 900. LO 1 1900 .00 1 1 \j () () • Go

15000 .0 14500.00 12100 • C0 12100 .00 12 100.'JO

20000.0 1 -(' -f 0 0 • :)() 14700. u" u 1'-t'700.00 l'-!7'JU .. UG

TABLE C7 (CONTINUED). TOTAL COST DATA FOR A 36 INCH PIPE CULVERT ON A 2~:1 SLOPE

r u r ~ A .3 bIN.. [J 1 A r·l F T L r( ,j 1 !.) L (J N A 2 - 1 / 2 T (j 1 5 L (I ~ L

ADT A=12FT. f..=lBFT. A=24FT. A=30F 1.

7~~C:.O ~~:H) Ct. 00 290() . 00 2700.00 270 Q. GO

lS00.0 5]00.00 4400. GO 4000.00 4000.00

n ? ~:i~) 0 .0 {)7UO.00 :~LOO • ClO 5200.00 ~)200.00 N W

:3000 • .) d~(j0.0u 7£:UC. ()O b500.00 6500. 00

1 ~)O 00.0 d -lOO. 00 7300 .. UO 6500 .00 6500.00

20000.0 1 l:;;(.,l.'.()O 9600. CO 6500.00 t',50 C. 00

TABLE C7 (CONTINUED). TOTAL COST DATA FOR A 36 INCH PIPE CULVERT ON A 2~:1 SLOPE·

I~~----~' ~-~-

AUT A=12FT. A:::18FT. A=-24FT. A::.,30FT.

7:=.0. G :.:' 3 (j (} .. (j 0 1 -"00 .. GO 1200.00 60 O. 00

l~-:'OO.() 4(,00 .. 00 3300. 00 2400.00 1 10 O. 00

() N £.:~t:)O.O t.)7CG.OO 4 bOO. OU 3500.00 1 60 O. 00 ..p.

3(;,00.0 '.)00 (;.00 () :.:.()O .. 00 4-rOO.Oo 220 C .. 00

1 ~,o 0 (j • (J '9 ;::'00 .. 00 6600 • CO 4800.00 2200.00

2000,).0 12i)(JC.OO 9200. 00 6600.00 3100.00

TABLE CB. TOTAL COST DATA FOR A 36 INCH PIPE CULVERT ON A 6:1 SLOPE '

n N (J1

A = 1 (:: r=-,. A=12 rOt. A= 1 b FI ..

h=24 FT. A:..::.:".!.4 f-T.

itU. c L L (I (J. (j C c.4ljO.00 £.:100.00 &::'3LO .00 2000.00

}:.)\..,(. .U 4 L_ G l,. .. u l ..... vUU .·00 ~(""H;.U() ..J~OO.OO 2t,OO.OO

::.:, i li IJ • V II 4 "00 • 0 () .:JIOO.OO qoOO .00 3000.00

..)v0U.U '( Li li () • :,.; c ~~00.0U -.l-iQU. OCt SbOO .00 360U.00

It.GG(I.{) 'f:') lu. u \., L0UO.00 ~-(O(;. GC t.) S. 00 .00 "':'oGO.GO

:i. \) 1 U u. \..1 V 1bO(i. (; (J 4600.00 1700.00 4oUO.OO

TABLE C8 (CONTINUED). TOTAL COST DATA FOR A 36 INCH PIPE CULVERT ON A 6:1 SLOPE

A='24 FT.

A=.30 rT.

1900.00

c.400.00

2YOO.00

3~Ou.OO

3500.00

4400.00

TOT AL COS T DF A l~lJAHDt~A IL P~OT L (TCO C lL VeRT

FOR A 36 IN. DIAMt:T(~!~ PIPt.: ON A 6 10 1 SLOPE

ADT J\ :;:: 1 2Fl . t, ;;.....1 bFT • A=24FT .. f'l = ::-:1 Of" T ..

750.0 o~GO.00 6900. lJ -, u L900.00 c,,<)GO. {,O

It>OO.O 10 !':',o 0 .. GO ~~600 • Gu [)oOO .00 _fiC>O (I,. uo

CJ N 22~O,.0 124Gu.no 0)

10200 · (,0 I02l)t) • on 1 0 c'(j l'~ • ( ,)

3000.0 14400.00 11900 • fJO 1 1 ,} () c; .. 00 1 1 ':.ld c. l'U

15000.0 14 !:.;0 Uoo 00 12 100 · (,0 1.: 100 .00 1 ,', .- 10 () .. 00

20000.0 177~)n.oo 14700 Of" 00 14700 .. ,00 147u G. ()()

TABLE C8(CONTINUED). TOTAL COST DATA FOR A 36 INCH PIPE CULVERT ON A 6:1 SLOPE

Ten AL ellS T (jF A. but-.rE i--)Rl)lLC fel' CULVf hT

f,.Dl A=I?Fl. f,.:::.1 dF T • A=-24F r. A=30FT.

-/~O. 0 b400 .. 00 6300. LO 8300.00 8300.aO

It'.'JO(j.0 ':/100.00 6800. GO EH300.00 680 o. 00

n N ~~ 2 50 .. 0 i..lIOO.OO 9300 .. (to ':J300.00 93CiO.OO -......J

300(1 .. U lLJ400.Ul) '}YOO. GO 9900.00 9900.00

l~)OOO.O I 0 lj () 0 .. 00 9900. no 9900.00 990 0.00

20000.Q 11000.00 10bOO .. GO lO6UO.OO 10600.00

TABLE C8 (CONTINUED). TOTAL COST DATA FOR A 36 INCH PIPE CULVERT ON A 6:1 SLOPE

lDTAL CO~,T UF Ahl Ui'H-'R.JTCC1FD CULVCf<T

FUf< A 4 X L F T ~ S I f',,(.Lr:' HO X (UL VfRl ON A 2 -1/2 TO 1 SLOPE

A.DT A,~12FT • A=lbFT. A=24FT. A=30FT~

7~) 0 .0 ::,t-:00.00 4 £: 00.00 3700.00 1300.00

1500.0 lObOu .. OO 8400.00 7400 .. 00 2500.00

() 3700 .. 00 N 22~,O. C 1 ~) :i () 0 • G 0 12300. CO 1 0900.00 CO

.jOOO.O 20t.luO .. OO 16600 • CO 14600.00 t> 00 0.00

lSO()v.O ;:_O"~(!O.00 16400.00 14900.00 5100.00

ZOOOO.O ~gOOO.00 ~3400 .. CO 20600.00 7100.00

TABLE C9. TOTAL COST DATA FOR A 41 X 6' SINGLE BOX CULVERT ON A 2~:1 SLOPE

I L', /.L CL,~ I F (it', L.AI LI'~() 11"", A CLJL VL. kJ

I-LI' /-, 'i A (. I- I. ~I r..;eLl. uL).. ClJLVL~<T lJl\ A c-l/~ 'II.J 1 SLUJ-'E

j; =. 1 £: f- 1 .. A~12 FT. A;.:. 1 t, rT. A=lb rT. A=-24 t-l.

r:. J. f'u,\ L l ,I r ~ L T J",=-lt', Fl. A;;: c' 4 F". A=30 Fl. A=-24 f-T. A=30 Fl.

AD r

~;!:..')l.i.VL. ~':.JOO.O() 4.jOO. 00 t; '+ (iO .00 4000. 00 :if~ 00 • (j 0

~t()\.}.0U SbOU.O() !jouu.00 ~.::.:uO .00 t!300.00 4900.00

1 ~:, ( C l; _ l, L 1 ~O (10. \) 0 oouO.OO 1 ;::bOO .00 tj~OO.OO 0100.00

~,,{) '-i L • v 1 f'..J U ~j. Uu I GLU0.0G t>100.00 1 b..j00 .00 -(t) GO. 0 () (400 .00

i (- L L I.' • l) L 1 -(vOO .0 u t,~(;G • 00 1 L600 .00 1':J00.00 'It:CO.OO

L. ' .. luU.vU c...cl:) 00. () 0 lO luv .vO 2c::3uO .00 ~:/t-OO • 00 ~A00 .00

TABLE C9 (CONTINUED). TOTAL COST DATA FOR A 41 X 61 SINGLE BOX CULVERT ON A 2~:1 SLOPE

TOTAL COST OF A (,UJ\!d)}<A IL PkCiTfCTED Cl.LVL:RT

ADT A:::l~~rl . /, =.:1 EFT . A=24FT. A="':.Or-T ..

7t:>O.O (3:)00.00 6900. CO 6~OO.OO 6 (.;; (; (I • C. 0

1500.0 10~OO.OO dbOO. O~) ,~bOD .GU c. b(J (! • () U

n w 2250.0 124(;0.00 10200.: a 00 10200.00 102.00 .. 00

3000.0 1440U.00 11 ':100 • LO 119UO.OO 1 1 \'(.i (;.,. ud

l::}OOO.O 14500.00 1 ~ 100 • 0,; 12100.00 12 1 [) () • CO

20000.0 1 "'" U 0.00 14 ((10 • (;C I If lCIO.O() 14lG{, .. uU

TABLE C9 (CONTINUED). TOTAL COST DATA FOR A 41 X 61 SINGLE BOX CULVERT ON A 2~:1 SLOPE

FC1R A 4 X (; fT. SlhlhLE he)>'. CULVk:i<T 01'1 A 2-}/2 TO 1 SLOPt:::.

t.Dl A = 1 ;;f r • A=lt<FT. A="24t=T .. A=3GFT.

7t0.0 LJ3CO.OO 3 bOO .. 00 3400.00 3400.00

1500.0 0400.00 ~")bOO. 00 4700.00 4700.00

() w 2.2!:) 0 • (J b40U.lJl) 7 100. CO ~900.00 !..>90(l.OO .......

::'iOOO.O lO!:;!Oli.OO <..1. L 0 0 • (/0 7100.00 7100.00

It:.OOO.O 10700.00 9000. 00 7200.00 7200.00

20000.0 1.::5":100 .. 00 11600 • 00 9200.00 920 0.00

TABLE C9 (CONTINUED). TOTAL COST DATA FORA 41 X 61 SINGLE BOX CULVERT ON A 2~:1 SLOPE

n w N

· ,

lUTAL CCS"I UF At.,) lJh.i~"'ROTt-:CIED CULVt:RT

F(jr~ A 4 X 6 FT. SINGLE bClX CULVEf~T ON A 6 TO 1 SLOPE

1\ = 1 2F T. A=18FT. A=24FT.

750 .. 0 37()O.OO 2600.00 1800.00

1GOO.0 7400.00 S~OO. CiO ~500.00

22~O.O lUhOO.OO 7600.00 5100.00

3000.0 14!Juu.()O 102 00. 00 6900.00

1 ~)O 0 (). 0 14-bOO.OO 10400 • 00 -rooD. 00

20000.0 .£:..ut:iOli.OO 145(;0.00 9800.00

TABLE CIO. TOTAL COST DATA FOR A 41 X 61 SINGLE BOX CULVERT ON A 6:1 SLOPE

A=3 OF 1.

60 0.00

1 10 O. 00

1600.00

2200.00

220 o. 00

3100.00

()

W W

'ILI'I-',L Lu~>l fL.k LAllhLJi'·'l. A CULVt-:RT

t, =:.·1 L rl. A=-12 f-l. A=.·lt: FT. A=:.:lb FT .. A::;24 Fl.

A ='2 '-t f'l. A='.,jO Fl. A:.::.:JO FI ..

... it CU. V l< ~:':"O().O(J :':;S(i0. (}O ..)(00 • () 0 3.)00.00 2bOO.00

, I,,; L l.' .. \J (; c10li.I.JU 4~0u.Uv ~J(JO .. 00 ..J~OO.,OO ;:)4 AU .00

~.'4 G l, • U U If (10 .. G G :';00U.OO -( 1 00 .. (j LJ 44-00.00 ~YOO.OO

..:suGv.u l.::u vI.,.,. vU '..>:J00.CO ~SO() .0(; b900.uO t,OOO.OO 4400.00

l~\J()C'.u 1 L~ J v. ()u ',(jOO .00 t.bOO.00 \J() GO .00 ~:OOO .. OO 4500.00

,UuuCI.0 1 L.:J Ul,. \.- U l~~(;(j.OO b4{)0.00 1 1 100.00 SbVO.OO 5;:)OO.UO

TABLE CI0 (CONTINUED). TOTAL COST DATA FOR A 4' X 6' SINGLE BOX CULVERT ON A 6:1 SLOPE

TDTAL COST OF A GUAkDRAIL ~RUTECTLO ClLV~kT

F (J t< A 4 X b F 1 ., S It \f b Lt:. Hex C U L V LR TON A 6 TO 1 ~; L u;::' ~~

ADl A = 1 ~Fl . A::: 1 eFT .. A =2/~ r- T • A =:.~:'" cr: T.

750.0 8~()O.OO 6900 • 00 6900.00 (, 'Jl) (,. CO

l~OO.O 1 ()!:;lCO. GO 6600. u,) (~·6 00. (.10 F,bf) L. CO

22t:.·O.O 1240(}.OO 1 () 20 0 • O{, 10200.0(; 1 (j ~ .. ;) (I. () ~.

3000.0 1440(~.00 11 ~oo .. OJ 1 }qoo.oo 1 1 ">fl o. ()d

1500(J.O 14~)no.ou I? 1 co. no I£.> 1 (; 0 • 00 1 ; Il,O.Cd

2.0000.0 1770(> .. 00 14 (00.00 14 -(00.00 14 l0 o. e(1

TABLE CI0 (CONTINUED). TOTAL COST DATA FOR A 41 X 61 SINGLE BOX CULVERT ON A 6:1 SLOPE

()

w U1

TOTAL CU~~T ()F .A. GI~AIC PIHJ rEelED CULVEPT

FGf< A 4 X £:, FT. SlI'-....!CLr-. HUX CULVL1~T UN: A 6 TU 1 SLOPE

AD"f /-\=12FT. t>.=lfFT. A=24FT. A=30FT.

7!>O .0 1 ~) :. () 0 • 0 0 1S200.('0 15200.00 1~2'OO. 00

l~JOO.O 10000.00 1 ~~ 100. GO 15700.00 15700.00

22 SO .. 0 16600.00 16~! 00 • CO 16200.00 16200.00

::>000.0 17,::)(jO.OO Ib(300.UO 16800.00 16(:100.00

1:') 000.0 17:'-';(lO.OO 16bOO.00 IbROO.OO 16800.00

20000.0 10400 .. 00 ]7700.00 1-(700.00 17700.00

TABLE CIO (CONTINUED). TOTAL COST DATA FOR A 41 X 61 SINGLE BOX CULVERT ON A 6:1 SLOPE

(J w 0)

TOTAL CO~.T (JF ,l\N UNPF<UTFC1ED CULVERT

ror< A 4 X l) FT. f\1UL TI -8 ox CULVl:: f~T ON A 2-1/2 TO 1 SLOPE

ADT A=l:::-Fl. A:::.18FT. A =2'~Fl. A=-3 OF T.

7 t) (; • (} IIOO.OO 6400.(:0 5500.00 1 ::lO 0.00

1 t)O-O. 0 14200.00 1~700. 00 1 1000.00 2500.00

2?~O.O 2GS<OO.,OO lE600.00 16100.00 3700.00

3000.0 2800U.00 ~:4000. 00 21600.00 500 0.00

lSOOO.O 2iH>0 0.00 25400. CO 22000.00 5100.00

20()()O.U 3'J600.00 ~~200. 00 30400.00 7"100.00

TABLE ell. TOTAL COST DATA FOR A 41 X 61 MULTI-BOX (2) CULVERT ON A 2~:1 SLOPE

F L h h .... X c t-'. I"> U L I 1 - L lJ /, ( U L V L F< 1 LA"; A 2. - 1 / C. -, U I ~L L P L

uFo, 1 G I ;"Ji-. L Lrf-!.: 1:. I i, ~ 1 '- F -, . A=l t: Fl . t.=- 12 F r. A=IL. t-T . A::..lb ~1 • A=Ll.4 Fl.

F 1'Y.AL LA': ~ .. :'-L -I j.~ - 1 c· r: I . i\ ::;...:::: Lj t- -J . A =-:"0 ~1 . A=-i::..4 fT . A::.......;,O FT. A..:::.30 FT.

JD I

(:"v.0 4...,1 (;(,.00 t t, 0 () .. (J 0 5L0e ... 00 7600 .. 00 4900.00 4100.00

i::.-")0.~J l<-f'-iuli.uv l,-+I...OO.u() c.';I L IJ • 0 () 1 ~l 00 .00 t:.100.00 ~300.00

L i::..:...:.O .. (j .::C":':'l;'J.l;0 1 S1(;0.00 6100.UO 162 UO .. 00 7300.00 t:oOO.OO

_i.jvl,. v i::.. CI L 0 l; • l. (; 24~(jO .VL, S:300.00 2.5-(00 .00 b600.0U leOO.OO

1:': L-(Jv.() t... 11 \, (; • C (, t...t...GGO.C0 440C .. O(J £: 4 1 00 .00 b'lOO.00 7900.00

<.:.v00u .v .:)L'-....\...l.i.0lt ..;;; ~'+ 0 (j .00 11400.00 .:J-~000.00 10700.00 9600.00

TABLE CII (CONTINUED). TOTAL COST DATA FOR A 4' X 6' r~ULTI-BOX (2) CULVERT ON A 2~:1 SLOPE

TOTAL COST OF A GUAf.:Di<AIL Pi~nTFCTE[) ClLVt:.f(T

F () I~ f.. 4 X 6 fT. ',1 U L r I -!j 0 X C U L V C F,r[ (\ N A .2 - 1 /2 TO 1 ~ L n p c

ADT A =1 ;'Fl . f\:::l t'Fl . A=?,!.FT. .A :::~-> Cl F- T •

7'1::J0.0 5t.~OO. 00 6900 . 00 6')(;0.00 69U O. C,('I

1500.0 10~O{).()O h6(;O. (, '\ ,. ,:)bOO • () e t:LO (.1. uu

n w 2~~tJO •. 0 12400.00 tOe'CO. CD 1 O?oc.oo lC2(iCi. i.; (~

0::>

21(,00.0 1440G.UO 11St00. LO 1 1 QOO .00 1 i '::;0 o. uG

15000.0 14=uO.00 12100. 00 1:::: 100.00 12 100._ C()

20000.0 17-' (10. ~o 14-lliO . Lt,: 14 10 (j .00 lq.rvu .. 00

TABLE CII (CONTINUED). TOTAL COST DATA FOR A 4' X 6' t1ULTI-BOX (2) CULVERT ON A 2~:1 SLOPE

lOTAL COSf O~ A GRATE PRUrCCTEO CULVERT

FOR A 4 X 6 FT~ MULTI-3UX CULVeRT ON A 2-1/2 TO 1 SLope

ADl A=12fT. A='16FT'. A=24FT. A=3 OFT.

7t>O.O 4, -to 0.00 4300., 00 4100.00 410U.OO

ItJOO.O 6!:";'O0.00 5800 • LQ 5400.00 54UO.00

n 2~:50.0 blOO.OD 7100.GO 6600.00 660 0.00 w

~

300U .. u 9~00.00 8600.00 7900.00 '790 O. 00

lSOOO.O 10100.00 5700. 00 7900.00 7'900.00

20000.0 12800.00 11 GOO .. uO 9900.00 9<)0 0.00

TABLE C11 (CONTINUED). TOTAL COST DATA FOR A 41 X 61 MULTI-BOX (2) CULVERT ON A 2~:lSLOPE

TUl'l,L COS T Ut- !\N ln~Pi~lJT [C TtD C ULVt:"RT

FDR A 4 X 6 FT. r"iUL 1 I -dOX CULVL!-'';:T 01'1 A 6 TO 1 SLOPE

ADT I\=-j~>t-=T. A=lbFJ. A=24FT. A=:iOFT.

750.0 5000.00 4000 .. GO 2600.00 60 0.00

1500 .. 0 11:500 .. 00 79UO.00 5200.00 1 100.00

2.2~O.O It.:·(}O.OO 11 600 • ().) 7500.00 1600.00

300G.O 22100.00 15600. r,o 10100.00 2200.00

1500G.O 22500.00 lS":IOU. CO 10300.00 ?200.00

20000.0 ..51200.00 £:2000. GO 14300.00 3100.00

TABLE C12 .. TOTAL COST DATA FOR A 41 X 61 MULTI-BOX (2) CULVERT ON A 6:1 SLOPE

CJb: lclNi\L lJ r- j- ~. 1:::.1 ;"'.::.-·1 L t-I A~l L: t-1 .. ~ -. M- 12 Fl • h=lb t=T .. A=l b FT. A=24 Fl . f ! [\u'L Uf f ~,~ I A~ 1 L' i- 'j' • A=-c.4 FJ . A='.::.O FT .. ;:""=~4 fT . A=.:.O Fl .. A='30 ~-r ..

Jl...u·1

, :.,.,(/ • v c,~ L \~ .. L L S~OO • C U ~ 100 .. OG 4,:->00 .Oli 4C:::00 .. ()O ~20() .00

l~ClJ. (j 1 ul Oll .. li0 (;,5G(i .. U(; 5-/00. UC (!JOO .00 4100 .00 3-100.00

...:,£~ ~ o .. (; I ..jL' (; \.1 .. V U ! lJ':)vG .0 G c.,2CJU. 00 S':-7GO .GO ::'cOO.OO 4300 .. 00

.....:t.f\...i(j .. L- 1 "Ie 0lJ .. 00 l,j~(;(j.Oli t,buL .va 1 £~~(jO .00 ~b00.00 4bGO.OU

1 ::.' lJ () ~; e, U 1 (, 1 Cl,; .. L (; 1 ~, to(j .0(; tb0u.UO 1 ~ 7uu .00 5bOO. 00 L.bOO .. 00

LV(jl;0 • v .24i:..'(il.L.I.; 1 -((.)u(;.O « -/000 .0(" 1 be. vO .00 0/00.00 5700 .. 0 {J

TABLE C12 (CONTINUED). TOTAL COST DATA FOR A 41 X 61 MULTI-BOX (2) CULVERT ON A 6:1 SLOPE

TOT ALe 0 ~,T 0 FAG U I~ FD n A I L PRO T 1-= C TEn C LL VE i:( T

FOR A 4 X 6 FT. r,lUL l I -.H LJ( CUL V i:- RT (ji'4 t, 6 TO 1 SLOPL.

ADT A ~12FT .. A =1 EFT. A=;::24FT .. A =.<~ OF·T •

750 • 0 8500.00 6900 • CO 6()OO.0(J 690 (J .. reo

1 t:. () 0 .0 lOt,(;li.00 hbGO. 00 f..\~(IU .00 0t~~)(}. DU

CJ 2250.0 12400.00 10200. C,O lQ200.00 lO£.'\.iO.~~iu ..j::::. N

3000.U 1440u.00 11 900. 0\) 11(100.00 1 1 '-j'::l L • (I lJ

l~)OOO.O 14 ~,o 0.00 12 1 00. co 1 2100 .00 12 laC. \)0

20000.U I -I -, (, 0 • u 0 14 rUO ... (,i. 1 47(iO .0 l) 14 -to C .. UC;

TABLE C12 (CONTINUED). TOTAL COST DATA FOR A 41 X 61 MULTI-BOX (2) CULVERT ON A 6:1 SLOPE

T CIT 1\ L C C) STU FAG ~ A T [ P 1-< () l LeT E D C U L V L ~T

'=01< A 4 X 6 Fl. f·1UL r ]-l-ilJX CULVERT ON A 6 TO 1 SLUPE

ADl A=12fT. A='lSFT. A=21~FT • A=30F 1.

206\'}O.O~) 20500.('.0 20500.00 2050 o. 00

1500.0 2.1300.00 21100.00 21100.00 .21100.00

21 ':400. 00 21600.00 21 60 o. 00

3000.0 .2:2000.00 22 I 00. 00 22100.00 22100.00

l~OOO.Q 22100.00 22200.00 22.200.00 2220 0.00

20000.0 23000. 00 23000.00 23000 .. 00

TABLE C12 (CONTINUED). TOTAL COST DATA FOR A 4' X 6' MULTI-BOX (2) CULVERT ON A 6:1 SLOPE

iL;ip.L L'},,\LCi C(.J~' Fu« LX'Lf\lUINl. A CUL\lLr-<l

~Lt~ A ~.(j 1l". L:ll-',I·,L'Lh. t-"!i-'L uN A 2-1/e:: T0 1 ~Ll.JPt:.

A~·l.·_ Fl. /:-..=-1" Fl. 1'\=--121-'1. A=-lt:-, fT. A=-10 Fl. A=-24 Fl.

I ... :::: 1 ,--. t-'l. r=(:4 r-l. A::.:-24 1-'1'. A=..)V FT. A=-,jO FT.

AUf

" c L, • 0 L 110(/.(;0 It:Cl; .. OL 1 1 GO .0(; I ICO.u(j 1700.00

ivv.Uv 1100.00 lSOO.OU 1 1 CO .. 00 lIOO.OO 1700.00

/OU.0L 11OO.OU lSOJ.00 1100 .00 lIOO.OO 1700.0G

IlJu .. uU 1 100 .0(; 1~O0.00 1100 .. 00 lIOO.UO 1700.00

1 ~=.;u(,l' .. \,,.l Iu u. 0 II I 1(;(;.00 IS00.0lJ 1 1 GO .. 0 0 1700.00 17'00 .. 00

"Ov.00 110U.00 l!JOO.uO 1 100 .. U 0 1700.",0 1700.00

TABLE C13. DIRECT COST DATA FOR A 36 INCH PIPE CULVERT ON A 2~:1 SLOPE

----------------------------~----

j., ~ 1 c.' 1-1. A~ U-. Fl. A=lb Fl ..

/I.=-1 b F I .. A=~O Fl. A=30 FT. A ='30 FT.

':.- () l,. i.,u 1£:.00.00 1 ~) C. 0 • 0 c.' 1 100.00 1400.L(; 130{).OO

~vv.uu 1';:.00.00 1500.00 1100.00 1400.00 1300.00

Sl,.v.v\... li.:O(J.OG 150(;.00 1 100 .0 Ci 1400.00 1300.00

JuUU .. U ':;1 (1\ .. ,; • (; {J J.£::OO.\)(J 1500 .. 00 1 100 .00 1400.00 1300.00

~; ~j () .. () (, 1.:::-00.()O I ~,oc • DO 1 100 .00 1400.0G 1300 .00

£::uGuU.0 \lOv.uu 14::00.00 1500.00 1100 .0 U 1400.00 1300 .. 00

TABLE C14. DIRECT COST DATA FOR A 36 INCH PIPE CULVERT ON A 6:1 SLOPE

P=-lt: Fl. A=l::::: Fl. II = 1 L Fr. A=lf.: For. A .::.2.4 Fl.

A=3(J ~I .. A='..)O FT. A=':':iO fl.

h,DI

I::' C' \.i • li 0 £::.1(;0.(,(; .310(;.00 } 700 .00 £.-:bUO.GO ~400 .00

l-.:.>vv.vU t:~lOO.OO .:)100.00 1700.00 £:,:(:500.00 2400.00

i..:',LL.LC i.'100.GU .J1uu.()U I', uu .00 e:bOO.U0 2400.00

l..:>Cli.vl. £:'100.,0(; .3100.00 1 -/00 .00 £::000.00 2400.00

.1 ~,U \) • U l; L..l 00.00 .;.,lUU.OO 17UO .. 00 2bOO.OO 2400.00

L . .i()\.I.uu '-.iOO.()0 :':duu.00 1700 .00 2bOO.vC 2400.00

TABLE Cl~ DIRECT COST DATA FOR A 41 X 61 SINGLE BOX CULVERT ON A 2~:1 SLOPE

FL:h ;:... " " L Fl. ~ 1 r'~C.LL L,LX CULVt h1 LJi\i A. C> 1(; 1 !.:.LCll-'t:

f' . .::.:.le: fT. A=lc. fT. A=-lb FT. A=-i:.4 Fl.

~\-l<· Fl. A=-c'4 Fl. A=24 ~l. ;'.::.';;0 F1 '"'

I.U;

1 () lj C • Uli .. ~500. () G ':::'400 • () 0 t:: 000 .0 L ;::bOO.UO £:,300.00

ic,0v .vv ~~!::> 0 () . () (: ':';;4vL; aUO 4000 .00 ~bOO.OO ~300 .00

1 '.()u. Ll ~~:U(;.()O 340u .00 ;;:u(;() .Ou 2bGO. 00 L.'300 .00

.J ali () • 0 lI.Ju\J. lIL ,-t.00 .oe 341'..H,,: • UC £:: U \)() .00 L.buCi a 00 ~3u0.0(;

iG 0L . Llv £:SOU . o (j ;.:040(; .00 L.O GO . 00 2600.00 2300.00

levu.uti c.:!J00.0() ,)400 .00 cO 00 .00 ~bOO. 00 ~3uO.OO

TABLE C16. DIRECT COST DATA FOR A 41 X 6 1 SINGLE BOX CULVERT ON A 6:1 SLOPE

('") . +::> CD

A=-lc. Fl. ;:"'.=12 t-T. /,,::·10 f"T. A::lt.~ ~T.

h~·l(.' f--'. A:::c'4 fT. A=·.;:;,O t-T. A=£:'4 FT. A=..jO f'l.

7 ':.... (j • (; j 7 G v. 0(; :"00(1 • (j U 4300.00 Ll (..10 .00 '::'cOO.OO

i I()U.UO ..j0 (J (I • () (. 't~O(;.0U 21 00 .00 ;:;'600. 00

1 lUu. U (, ~iO 0 (J .00 4~Ol; .(;(; ~ 1vO .00 ,:,:,c.. () 0 .. 00

..:.. l' (; LJ • 1.., } /L.l).l.ll.o .J0CU .0 G 4..JOv .00 Ll (10 .00 :.:H., 0 U .. 0 (j

1 ( (; l,l .. l. L _/00 G .. () (, 4:::'00 .00 c' 1 \)0 .00 2,600 .. 00

1 (l!ll .. tH; ;,)000.00 4JOu.00 c. 1 00 .0 v ::'000.00

TABLE C17. DIRECT COST DATA FOR A 41 X 61 MULTI-BOX (2) CULVERT ON A 2~:1 SLOPE

A=-£::4 f-T.

A=30 F·f.

cbOO.ClO

£>600.00

"_bOG.OO

LcOD.OO

£:.60U .. 00

cliOO.OO

I .. :;. 1 2 f- T • f, ::. 1 c' fl. A:....·lb ~1. A:=:16 Fl. A:=:24 F"'. t";il\J/\L Lf-r~t:..' A::'':':;O FT. A::.:Ctf Fl. A=..JO FT ..

I ... U I

LL·UO.l'll :)400 • (I 0 46(;U. 00 c4 uO .00 3bOO.00 2600.00

',;;\,;If.v ..... ~li Cu. u (I 460U.00 '=::400 .OU 3000.00 ~:bOO .00

L_ £~ 0 Li • U\'j :.~ Lt CO.OC 460u.UO ~400 .00 .,:H> 0 0 • 00 ~'bOO .00

:::,,£:.u0.vl. ~400 .00 4600. 00 24 vO .00 ~600.00 2000.00

1::' (; 0 U • 0 I.. L. 0 u. uU .... 400.0C 4r"uu .nu £:4 uO .00 ...::;(>00.00 £:.600.00

L:..u l, l.Jv • U ~_i.:.:O\,j.vll ~A 00 .OG 4t...00.00 .24-00 .00 3bOO.OO 2600.00

TABLE C18. DIRECT COST DATA FOR A 41 X 61 MULTI-BOX (2) CULVERT ON A 6:1 SLOPE

Example 1: Given:

APPENDIX D SAMPLE CALCULATIONS

A 4 ft x 6 ft double box culvert is located on a 2~ fill section rural highway with an average daily traffic of 2250. The end of the culvert is 24 ft from the edge of the traveled way and has no other hazards on the slope or around the culvert and ditch. There are no restrictions on the type of safety treatment which may be used.

Required: Determine the most cost-effective alternative. Solution: a) 1) Select Figure 10 (2~:1 slope).

Example 2: Given:

2) Enter with ADT = 2250 and Offset = 24 ft. 3) The point ADT = 2250 and A = 24 ft falls

to the right of the line for two 4 ft x 6 ft MBC. Therefore, safety treatment is recommended.

4) Select Figure 7 (4 ft x 6 ft multi-box (2) culvert on a 2~:1 slope).

5) Enter with ADT = 2250 and Offset = 24 ft. 6) Safest alternative is either extend to 30 ft or

grate protection.

A 36-in. diameter pipe culvert is located on a2~:1 fill section rural highway with an average daily traffic of 1500. The end of the culvert is 18 ft from the edge of the traveled way and has no other hazards on the slope or around the culvert and ditch. There are no restrictions on the type of safety treatment which may be used.

Required: Determine the total costs and ranking factors for a) the unprotected culvert; b) extending the culvert end to 30 ft; c) guardrail protection; and d) grate protection for the direct costs listed in Tables B6 through B8; e) repeat steps a) through d) for 30% decreased direct costs in extending and grate treatments; f) determine most cost~ effective alternative for no increase or decrease in direct costs and for 30% decreased direct costs.

01

Solution: a) Unprotected Culvert From Table C7: CT = $5100 (ADT = 1500, A = 18 ft)

R = 1.0 (see Appendix B for discussion)

b) Extend Culvert End to 30 ft From Table C7: CT = $4200 (ADT = 1500, Ao = 18 ft, AF = 30 ft)

From Table Cl: R = 0.52 (ADT = 1500, Ao = 18 ft, AF = 30 ft)

c) Guardrail Protection: From Table C7: CT = $8600 (ADT = 1500, A = 18 ft)

From Tab'l e C1: R = -0.67

d) Grate Protection From Table C7: CT = $4400

From Table C1: R = 0.47

e) 1) Unprotected Culvert (no direct costs involved) CT = $5100

R = 1.0

2) Extend Culvert End to 30 ft (30% decrease in direct costs) From Table C13 or Table B6: CTO = $1700

To calculate the new total costs: CT = $4200 - (30%)($1700)

CT = $3690

02

f)

Using Equation (B5) to calculate the ranking factor:

_ $5100 - $3690 R - (70%){$1700)

R = 1 .18

3) Guardrail Protection (no decrease in direct costs) CT = $8600

R = -0.67

4) Grate Protection (30% decrease in direct costs) From Table B8: CTO = $1500

CT = $4400 - (30%)($1500)

CT = $3900

_ $5100 - $3900 R - (70%)($1500)

R = 1.14

No increase or decrease in direct costs. From parts a) - d) : CT = $5100, R = 1.0 for unprotected culvert;

CT = $4200, R = 0.52 for extending to 30 ft;

CT = $8600, R = -0.67 for guardrail 'protection;

CT = $4400, R = 0.47 for grate protection.

and

Based entirely on total costs, extending appears to be the most cost-effective solution; however, it has a ranking factor less than 1.0. This means that more money must be spent than will be received in benefits by extending to 30 ft. Thus, the most cost-effective alternative is to leave the culvert unprotected. This can also be deter­mined by entering Figure 3 with AOT = 1500 and Offset = 18 ft.

30% decrease in direct costs From part e): CT = $5100 R = 1.0 for unprotected culvert;

03

Example 3: Given:

Required: Solution:

CT = $3960 R = 1.18 for extending to 30 ft;

CT = $8600 R = -0.67 for guardrail protection; and

CT = $3900 R = 1.14 for grate protection

Based on total costs and ranking factors, extending appears to be the best alternative. However, the total cost and ranking factor for grate protection is so near that of extending, that either alternative is considered the most cost-effective.

A 4 ft x 6 ft single box culvert is located on a 6:1 fill section rural highway with an average daily traffic of 3000. The end of the culvert is 12 ft from the edge of the traveled way and has no hazard on the slope or around the culvert and ditch. Right-of-way space is limited so that the culvert can be extended a maximum of 24 ft from the edge of the traveled way. Determine the most cost-effective alternative. 1) Select Figure 11 (6:1 slope). 2) Enter with ADT = 3000 and Offset = 12 ft. 3) The point ADT = 3000 and A =12 ft falls to the right

of the line for one 4 ft x 6 ft SBe. Therefore safety treatment is recommended.

4) Select Figure 6 (4 ft x 6 ft single box culvert on a 6:1 slope).

5) Enter with ADT = 3000 and Offset = 12 ft. 6) Safest alternative is to extend to 30 ft. This alternative is not possible due to limited right-of­way; thus, the alternative with the next highest ranking factor is the most desirable. Extending the culvert end to 18 or 24 ft might also be a possible treatment. From Table C4: R = 1.0 for unprotected culvert; R = 2.69 for extending culvert end to 30 ft (not a

possible alternative);

04

Example 4: Given:

R = 1.99 R = 1.37

for extending culvert end to 24 ft; for extending culvert end to 18 ft;

R = 0.02 for guardrail protection; and R = -0.19 for grate protection. For this, extending to 24 ft clearly provirles the second highest ranking factor next to extending to 30 ft. Thus, the culvert end should be extended to a final offset of 24 ft to obtain the second most cost-effective solution. This same procedure can be applied to other situations in which the recommended alternatives in Figures 3 through 8 cannot be implemented.

A portion of highway has been designed for an average daily traffic of 20,000 and will be located on a 6:1 fill section. A 4 ft x 6 ft single box culvert is necessary for drainage under the roadway at Station 1+00. All hazards within 50 ft of the traveled way and 100 ft on either side of the culvert have been removed. The culvert end cannot be closer than 12 ft and no farther than 30 ft from the edge of the traveled way. Assuming no initial costs for an unprotected culvert with a 12 ft offset, it has been determined that the following additional costs are necessary: $3500 for an 18 ft offset, $7000 for a 24 ft offset, and $11,000 for a 30 ft offset. All costs include labor and material for extending the culvert and for the necessary fill to maintain a 6:1 slope.

Required: Determine the most cost-effective culvert end offset and/or safety treatment at Station 1+00.

Solution: The general procedure is to determine the total cost and ranking factor at each offset for the unprotected, guard­rail protected, and grate protected culvert. The costs given above must be used in conjunction with the costs given in Appendices Band C.

D5

1) The Unprotected Culvert (see Table Cl0) 12ft Offset: CT = $20,500 (from Table Cl0)

CTO = $0

R = 1.0

18 ft Offset: CT = $3500 + $14,500 = $18,000

CTO = $3500

R - $20,500 - $18,000 = 0 71 - $3500 ·

24 ft Offset: CT = $7000 + $9800 = $16,800

CTO = $7000

R - $20,000 - $16,800 = 0 53 - $7000 ·

30 ft Offset: CT = $11,000 + $3100 = $14,100

Cro = $11,000

R = $20,500 - $14,100 = 0 58 $1',000 ·

2) The Guardrail Protected Culvert (see Tables 87 and Cl0) 12 ft Offset: CT = $17,700 (from Table Cl0)

CTO = $6900 (from Table 87)

R - $20,500 - $17,700 = 0 41 - $6900 .

18 ft Offset: CT = $14,700 + $5500 + $3500 = $23,700

CTO = $5500 + $3500 = $9000

R - $20,500 - $23,700 = -0.36 - $9000

06

24 ft Offset: CT = $14,700 + $5500 + $7000 = $27,200

CTD = $5500 + $7000 = $12,500

R ~ $20,500 - $27,200 = -0.54 - $12,500

30 ft Offset: CT = $14,700 + $5500 + $11,000 = $31,200

CTD = $5500 + $11,000 = $16,500

R = $20,500 - $31,200 = 0 65 $16,500 - ·

3) Grate Protected Culvert (see Tables 88 and C10) 12 ft Offset: CT = $18,400 (from Table C10)

CTD = $14,600 (from Table 88)

R - $20,500 - $18,400 = 0.14 - $14,600

18 ft Offset: CT = $17,700 + $3500 = $21,200

Cro = $14,600 + $3500 = $18,100

R - $20,500 - $21,200 = -0.04 - $18,100

24 ft Offset: Cr = $17,700 + $7000 = $24,700

Cro = $14,600 + $7000 = $21,600

R - $20,500 - $24,700 = -0.19 - $21,600

30 ft Offset: CT = $17,700 + $11,000 = $28,700

CrD = $14,600 + $11,000 = $25,600

R - $20,500 - $28,700 = -0.32 - $25,600

07

From these calculations, the most cost-effective alternative, based on ranking factor, is to leave the culvert unprotected at a 12 ft offset distance (CT = $20,500; R = 1.0). Based on total costs, the best alternative is to leave the culvert unprotected using a 30 ft offset (CT = $14,100; R = 0.58). Note that the additional initial costs used in this example greatly influence the final results since they are a large percentage of the total and direct costs. Care should be taken in estimating these costs in order to obtain correct results.

D8

APPENDIX E REFERENCES

1. Guide for Selecting, Locating, and Designing Traffic Barriers, Part I, American Association of State Highway and Transportation Officials, 1977, pp. 15-21, 156-186, 222.

2. Hutchinson, J.W. and Kennedy, T. W., IIMedians of Divided Highways -Frequency and Nature of Vehicle Encroachments," Bulletin 487, University of Illinois Engineering Experiment Station, 1966.

3. Glennon, J. C., "Roadside Safety Improvement Program on Freeways -A Cost-Effectiveness Priority Approach,1I National Cooperative Highway Research Program Report 148, 1974, 64 pp.

4. Weaver, G. D., Post, E. R., and French, D. D., "Cost-Effectiveness Program for Roadside Safety Improvements on Texas Highways - Volume 2: Computer Program Documentation Manual, 1.1 Research Report 15-1, Texas Transportation Institute and Texas Highway Department, February 1975.

5. Memorandum to T. J. Hirsch, R. M. Olson, E. L. Marquis, G. D. Weaver, C. E. Buth, D. L. Ivey, J. E. Martinez, M. E. James, D. L. Woods, and G. E. Hayes, Texas Transportation Institute; Harold Cooner, Ray Ratcliff, and Gerald Peck, Texas State Department of Highways and Public Transportation; and C. P. Damon, Federal Highway Administration, from Terry L. Kohutek of Texas Transportation Institute, Texas A&M University, April 5, 1977, concerning the severity index of various roadside hazards.

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