#55 Clark Co DOT Bridge Rec Wing

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To: Nathan Beaver – Clark County Parks and Programs Manager

CC: Brian Duell – Clark County Highway Commissioner

AECOM 200 Indiana Avenue Stevens Point, WI 54481 aecom.com

Project name: CTH G Snowmobile Trail Concept

Project ref: Locally Funded by Clark County AECOM Project Number 60645919

From: Kevin Hagen - AECOM

Date: April 12, 2021

Subject: Concept Design and Costs for Snowmobile Trail over Black River at CTH G

Background

The Clark County Forestry and Parks Department is preparing a grant application to fund the design and construction of a

snowmobile trail over the Black River in Greenwood. The trail would cross the river on the proposed CTH G Bridge which is

currently being designed under the Wisconsin Department of Transportation’s (WisDOT) Local Bridge Program. Any costs

associated with adding a snowmobile trail to the proposed CTH G Bridge would not be covered under the Local Bridge

Program. This memo provides a description of the snowmobile trail bridge concept and the associated costs and real estate

impacts for inclusion in the grant application. If funding is awarded for this snowmobile trail, the plans for the proposed CTH

G bridge would be updated to include the trail in fall 2021. This project is currently scheduled to be let for construction by

WisDOT in November 2022 with construction anticipated in 2023.

Trail Bridge Concept Description

The proposed crossing of the Black River consists of a trail on the north side of the proposed CTH G Bridge. The new bridge

that would carry both CTH G and the snowmobile trail would be a 3-span prestressed concrete girder bridge with an overall

length of approximately 316 feet. The bridge would be skewed at 25-degrees to match the direction of the Black River, and it

would be supported by sill-type abutments founded on piling and hammerhead piers founded on spread footings. The bridge

cross-section would include a 32-foot clear roadway width for CTH G (12-foot lanes and 4-foot shoulders), a 42SS concrete

barrier separating the roadway from the snowmobile trail, and then a 12-foot wide snowmobile trail on the north side of the

bridge. Open metal traffic railings would be installed at both the south and north edges of the bridge deck. A polymer overlay

would be placed on the 12-foot wide snowmobile trail to mitigate early deterioration of the concrete due to snowmobile use.

A hydraulic analysis was completed for the proposed structure, and to meet freeboard requirements the roadway profile at

the bridge will be raised approximately 12 inches. A grade raise would be required regardless of the snowmobile trail. The

grade raise will require approximately 140 feet of roadway reconstruction on the east end of the bridge and approximately

200 feet of roadway reconstruction on the west end of the bridge. The longitudinal grade on the proposed bridge will be

0.3%, which is below the desirable minimum grade of 0.5%. As such, a deck drainage analysis was completed for the

proposed structure in accordance with Chapter 29 of the WisDOT Bridge Manual. This analysis showed that without floor

drains, stormwater from the design storm would have a maximum spread of approximately 8’-2” from the gutter line. This is

acceptable because the design speed on this stretch of CTH G is 30 mph. Per chapter 29 of the Bridge Manual, for design

speeds of less than 45 mph, the maximum gutter flow is restricted to a spread width of the shoulder plus one-half of the

adjacent driving lane which totals to 10’-0” on this structure. Therefore, bridge floor drains would not be required. A concrete

surface drain with a drop inlet structure will be required off the west end of the bridge to collect the storm water flowing in the

gutter line of the barrier separating the roadway from the trail. Stormwater would then drain from the drop inlet into a pipe that

runs under the trail and outfalls in the roadway fore slope. Storm water that falls onto the trail and south side of CTH G will

drain over the edge of the deck through the open metal traffic railings.

The snowmobile trail approaches to the bridge will extend to the curb and gutter coming off Reese Avenue to the east and to

the wellhouse driveway on the north side of CTH G to the west. Additional fill and grading for the trail approaches will be

required on the north side of CTH G. The trail approaches will be surfaced with a 6-inch layer of ¾” crushed aggregate.

CTH G Bridge Snowmobile Trail Concept Design and Costs Clark County

AECOM 2/2

Beam guard will be required at the bridge approaches due to the traffic volume on CTH G (1,400 vehicles per day). On the

north side of CTH G, the beam guard will be attached to the 42SS barrier separating the roadway from the snowmobile trail.

A timber rub rail will be installed on the backside of the beam guard posts to minimize the potential snagging hazard to

snowmobiles using the trail. In addition, a 20-foot long timber post and rail fence will be installed with a 2-foot flare at the

north side of the side of the snowmobile trail to “funnel” users onto the bridge and to protect them from the riprapped

embankments below the bridge. The width of the trail adjacent to the bridge approaches will be 15 feet to provide 2 feet of

shy distance to the beam guard and 1 foot to the fore slope.

Real Estate Impacts

The real estate required to construct the snowmobile trail crossing and approaches was determined by completing a

conceptual layout of the proposed CTH G bridge that included the snowmobile trail and comparing it against the layout for

the proposed layout for the roadway bridge only. This comparison shows that approximately 0.198 acres is required to

construct the snowmobile trail. All of the additional real estate is located on the north side of CTH G. See Exhibit 1, attached

to this memo, for details.

Design and Construction Costs

The total estimated cost for adding a snowmobile trail to the proposed CTH G Bridge over Black River was determined based

on the conceptual design shown in Exhibit 1 and are summarized in Exhibit 2, attached to this memo. Total costs include

construction, right of way, compensable utilities, and design and construction oversight fees. This cost estimate represents

only the anticipated cost for adding a snowmobile trail to the proposed CTH G Bridge and are in addition to the costs for the

roadway bridge itself.

If you have any questions or need clarifications, please contract Kevin Hagen, AECOM, at (715) 342-3053.

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WISDOT/CADDS SHEET 42

EHWY: COUNTY:C:\ONEDRIVE\AECOM DIRECTORY\60645919 - CTH G, CLARK COUNTY - GENERAL\900_CAD_GIS\910_CAD\78400303\SHEETSOTHER\ROW_NEEDS.DWGFILE NAME : 4/12/2021 8:41 PMPLOT DATE : PLOT BY : DAY, JOHN

2

PROJECT NO:PLOT NAME :

2

SHEET PLOT SCALE : 1 IN:100 FT

7840-03-73 CTH G CLARK ANTICIPATED RIGHT-OF-WAY NEEDS

LAYOUT NAME - Plan 1 IN 40 FT

BLAC

K RI

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CTH G

N R

IVER

RD

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E AV

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EESE

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LEGEND

EXISTING RIGHT-OF-WAY

PROPOSED RIGHT-OF-WAY NEEDSWITHOUT SNOWMOBILE TRAIL

PROPOSED ADDITIONAL RIGHT-OF-WAYNEEDS WITH SNOWMOBILE TRAIL

SLOPE INTERCEPT WITHOUTSNOWMOBILE TRAIL

SLOPE INTERCEPT WITHSNOWMOBILE TRAIL

SNOWMOBILE TRAIL

AREA = 0.139 AC

AREA = 0.017 AC

AREA = 0.012 AC

AREA = 0.038 AC

AREA = 0.140 AC

AREA = 0.058 ACBEGIN TRAIL STA. 6+72.00

END TRAIL STA. 13+33.95

BEGIN BRIDGESTA. 8+42.60

END BRIDGESTA. 11+57.41

15' 3/4" CABCSNOWMOBILE TRAIL

APPROACH (TYP.)

STRUCTURE B-10-398 REQUIRED± 315' OVERALL LENGTH32' CLEAR ROADWAY WIDTH12' CLEAR SNOWMOBILE TRAIL WIDTH

TIMBER FENCETIMBER FENCE

TYPE MRAILING (TYP.)

SINGLE SLOPEPARAPET 42SSMODIFIED

POINT REFERRED TO ONPROFILE GRADE LINE

C/L CTH G

45W' PRESTRESSED GIRDERS

TYPICAL SECTION ON BRIDGE(LOOKING EAST)

FT

0 100 200

SNOWMOBILE TRAIL

EXHIBIT 1

Snowmobile Trail Crossing of Black River

Proposed for Completion under WisDOT Project ID 7840-03-03/73

USH 10 - Greenwood

CTH G

Clark County

Cost Estimate Summary

Conceptual (0 - 30%) Cost Estimate

Estimated Additional Costs to Add Snowmobile Trail to Proposed CTH G BridgeItem No. Item Description Trail Crossing Costs Notes

1 Trail Approach 56,000.00$ Additional cost for approximately 350' of trail approach to CTH G Bridge.

2 Bridge 614,000.00$ Additional cost to add 12' wide snowmobile trail to CTH G Bridge.

3 Right of Way 5,000.00$ A total of approximately 0.198 acres would be required from 2 property owners.

4 Compensable Utilities 10,000.00$ Slope intercept with trail crosses city waterline outside of right of way. Allowance added to cover potential adjustments.

Sub-Total 685,000.00$

Contingency @ 20% 137,000.00$

TOTAL CONSTRUCTION COST (Rounded) 822,000.00$

Final Design Engineering @ 10% 82,200.00$ Includes updating agency & utility coordination, design, plat & right of way acquistion fees.

Construction Related Services @ 15% 123,300.00$

TOTAL PROJECT COST

(Rounded)1,028,000.00$

April 12, 2021

EXHIBT 2