Welcome to the

SD44 / Platte-Winner Bridge Corridor Study

and Environmental Assessment

Open House 5:30—7:00 pm

Presentation at 5:45 pm

Please sign-in, review project materials, talk with project staff,

and provide comments.

SD44 / Plae-Winner Bridge Corridor Study and Environmental Assessment

Project Objec!ves

This study will fulfill the planning and Na!onal Environmental Policy Act (NEPA)

ac!vi!es necessary to meet the following objec!ves:

1. Complete a structure loca�on and type study for a new long-term (100+ years)

performing bridge and associated roadway alignment considering economics,

aesthe�cs, maintenance, and impact to the environment.

2. Complete the NEPA process necessary to advance the project into final design

phase.

3. Complete a safety analysis of the highway corridor within the study area.

4. Iden�fy loca�ons on the highway corridor within the study area not in

compliance with current design standards under both the current and

forecasted future traffic condi�ons.

5. Create final products for use by SDDOT which will guide the DOT during the

design phase of the bridge replacement and related corridor improvements

project.

SD44 / Plae-Winner Bridge Corridor Study and Environmental Assessment

Project Schedule

2017 2018

Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Jan Feb Mar Apr May June

We

are

he

re.

Traffic Studies, Geotechnical

Review, and Data Collec2on

Environmental Studies and

Agency Coordina2on

Bridge and Roadway Concept

Development

Determine Preferred Alterna2ve(s)

for Bridge and Roadway

Prepare Environmental

Assessment

Publish Environmental

Assessment

Public Mee2ngs

#1 #2 #3

SD44 / Platte-Winner Bridge Corridor Study and Environmental Assessment

Geotechnical Resources

Surface Geology

The project study area surface is dominated by residual

shale soils

These soil types are prone to loss of strength and sliding

Several landslides have occurred along the existing SD44

corridor (shown above)

However, SDDOT improvements have allowed the focus to

be on maintenance of the roadway versus emergency

response over the last several years

Slopes

The SD44 corridor and surrounding environment is

characterized by steep slopes (shown in red above)

The combination of residual shale soils and steep slopes

creates a challenging environment for maintaining a

stable road corridor

SD44 / Plae-Winner Bridge Corridor Study and

Environmental Assessment

Exis�ng Bridge and Proposed Bridge Features

Exis�ng SD44 Bridge

Exis�ng SD44 Bridge

• Opened to traffic in 1966

• Over 1-mile long, with 28 piers

• Roadway is 28 feet wide

• Closed to traffic for four months in

1997 due to major repairs

• Detour length is approximately 85

miles

Proposed SD44 Bridge Features

• Designed for a 100-year service life

• Con'nuous use of the exis'ng bridge

for traffic during construc'on of a new

bridge (requires the bridge to be built in

a new loca'on)

• Con'nuous capability for watercra, to

travel through the construc'on zone

during construc'on of the bridge

• A wider roadway than exis'ng (36 feet

wide is shown here tonight)

SD44 / Plae-Winner Bridge Corridor Study and Environmental Assessment

Major Bridge Type Alterna!ves

Girder/Slab

Exis�ng SD44 Pla�e-Winner Bridge (Missouri River)

Segmental

Four Bears Bridge (Missouri River)

New Town, ND

Arch

Highway 61 Bridge (Mississippi River)

Has�ngs, MN

Truss

I-70 Blanche�e Memorial Bridge (Missouri River)

St. Louis, MO

Cable Stay

US 82 Bridge (Mississippi River)

Mississippi-Arkansas Border

Suspension

Golden Gate Bridge

San Francisco, CA

Images of Representa�ve Major River Crossing

Bridge Types

Preliminary Evalua�on of Bridge Type Feasibility

Bridge Type

Aesthe!cs Typical Span Ranges

Constructability Construc!on Cost Evalua!on of Feasibility for the SD44 Corridor

Girder/Slab

0 0 / + + 0 / + +

conven�onal girder slab

look, variable depth gird-

ers add interest

100= to 450=

Conven�onal materials,

precast or steel girders

with concrete deck

conven�onal materials

and cost

feasible due to achieving longer

spans with conven�onal materials

Segmental

+ 0 / + 0 0 / - +

tapered box shape, varia-

ble depth adds interest 150= to 650=

concrete, special forms

and equip, simultaneous

erec�on at mul�ple

bents

somewhat expensive

compared to conven�onal

feasible due to longer spans elimi-

na�ng substructure

Arch

+ + - - -

long spans with open look 200= to 700=

cri�cal / complex con-

nec�ons, temporary sta-

bility of arch ribs cri�cal

expensive, shipping/

erec�on logis�cs

not feasible due to high cost and

complex construc�on

Truss

- + - - -

boxy imposing shape with

lots of chord members de-

tract from landscape

400= to 800= labor intensive / non-

redundant connec�ons expensive due to labor

not feasible due to high cost and la-

bor intensive fabrica�on and erec�on

Cable Stay

0 / - + - - (2) -

tall towers that may look

out of place 500= to 1200=

highly specialized erec-

�on requirements very expensive

not feasible due to very high cost and

specialized construc�on

0 / - + - - (2) -

tall towers that may look

out of place 1000= to 4000=

highly specialized erec-

�on requirements very expensive

not feasible due to very high cost and

specialized construc�on

Note:

“+” = Favorable

“0” = Neutral

“-” = Not Favorable

Suspension

SD44 / Plae-Winner Bridge Corridor Study and Environmental Assessment

Environmental Assessment Study Area and Process

The EA process can be defined by three

dis#nct steps:

1. Assess project needs and research

the exis�ng environment;

2. Iden�fy poten�al project

alterna�ves and evaluate their

impacts on the environment;

3. Prepare EA document with

recommended alterna�ve.

At the end of this process, the EA is

made available to the public for

comments that will be considered by

FHWA to determine whether the

project will cause significant impacts

on the environment.

Environmental Assessment (EA) Study Area

SD44 / Plae-Winner Bridge Corridor Study and Environmental Assessment

Environmental Assessment Key Issue: Recrea"onal Resources

The Missouri River within this study area

is prominent for its abundance of

recrea"onal resources, including:

• Three State of South Dakota Recrea�on

Areas

• Mul�ple Game Produc�on Areas (GPAs)

These resources are considered to be

“Sec"on 4(f)” resources, which require

addi"onal evalua"on as part of an EA.

• The Snake Creek Recrea�on Area will be

impacted by reloca�on of the bridge.

• Coordina�on with SDGFP and the U.S. Army

Corps of Engineers will be necessary to

mi�gate any adverse impacts to the park.

Snake Creek Recrea"on Area has also received Land and Water

Conserva"on Fund (LWCF) grants, which requires further

coordina"on with SDGFP and Na"onal Park Service

SD44 / Plae-Winner Bridge Corridor Study and Environmental Assessment

Current and Future Traffic on SD44

Based on recent traffic counts in the study area and forecasts:

• Average daily traffic volumes are expected to steadily grow through 2050 (bridge traffic today: 835 vehicles/day and in 2050

1,420 vehicles/day); however there are no iden&fied concerns about capacity on the SD44 corridor through this &meframe.

• Heavy trucks and recrea&onal vehicles are common in the corridor.

• Higher traffic volumes have been observed during recrea&onal peak periods (notably summer and around holidays).

2017 Traffic Volumes 2050 Forecast Traffic Volumes

SD44 / Plae-Winner Bridge Corridor Study and Environmental Assessment

Traffic Safety on SD44—Crashes in the 2012-2016 Timeframe

Based on review of crashes over the last five years:

• The majority of crashes are animal collisions and/or single-vehicle crashes

• One single-vehicle crash occurred at an intersec&on in the corridor, intersec&on conflicts do not appear to be a concern

• While the Snake Creek Recrea&on Area can be par&cularly ac&ve, crashes around it consisted of animal collisions

• Crash rates for the corridor are generally low, the horizontal curves in west of SD1806 have the greatest concentra&on of injury

crashes

2012-2016 Crashes by Severity 2012-2016 Crashes by Manner of Collision

SD44 / Plae-Winner Bridge Corridor Study and

Environmental Assessment

Poten�al Bridge Types—Design Features (1 of 4)

Simple Span Made Con�nuous

I-25 simple span bridge in Grand Junc�on, CO

SD44 / Plae-Winner Bridge Corridor Study and

Environmental Assessment

Poten�al Bridge Types—Design Features (2 of 4)

Spliced Precast Concrete Girder—Variable Depth

Spliced Precast Concrete Girder—Constant Depth

Virtual rendering of a variable depth spliced precast

concrete girder bridge

SD44 / Plae-Winner Bridge Corridor Study and

Environmental Assessment

Poten�al Bridge Types—Design Features (3 of 4)

Con�nuous Composite Steel Girder—Variable Depth

Con�nuous Composite Steel Girder—Constant Depth

The SD44 bridge includes variable depth girders

SD44 / Plae-Winner Bridge Corridor Study and

Environmental Assessment

Poten�al Bridge Types—Design Features (4 of 4)

Span by Span Precast (Concrete) Segmental

Balanced Can�lever Precast (Concrete) Segmental

The Four Bears Bridge in North Dakota is an example

segmental bridge.

Thank You! Please Leave a Comment Please provide your input about the SD44 / Platte-Winner Bridge and Corridor Study Project. Comment forms are

available at the registration table. You may leave your comment here or email / mail your comment to Tim Thoreen

or Steve Gramm by June 6, 2017.

Project Website: www.sd44bridge.com

Project Contacts Tim Thoreen, PMP Steve Gramm, PE

HR Green, Inc. South Dakota Department of Transportation

651-659-7777 605-773-6641

tthoreen@hrgreen.com steve.gramm@state.sd.us