A Common Sense Approach to Selecting Bridge Sites

Trail BridgesTrail Bridges – – A Common Sense Approach A Common Sense Approach

to Selecting Bridge Sitesto Selecting Bridge SitesPresenter:Presenter:

James “Scott” Groenier, P.E.James “Scott” Groenier, P.E.Project Leader, MTDC, WITProject Leader, MTDC, WIT

Prepared for: NOHVCC ConferencePrepared for: NOHVCC Conference Ontario, CA Ontario, CA

March 17, 2005March 17, 2005

22

Technology & Development

IntroductionIntroduction Site ReconnaissanceSite Reconnaissance Geomorphology ConcernsGeomorphology Concerns Hydrology and HydraulicsHydrology and Hydraulics AlignmentAlignment Environmental Concerns Environmental Concerns Design LoadsDesign Loads Trail Bridge WebsiteTrail Bridge Website SummarySummary

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Site ReconnaissanceSite Reconnaissance Site Investigation - simpleSite Investigation - simple

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Site ReconnaissanceSite Reconnaissance Site Investigation - ComplexSite Investigation - Complex

Streambed strata

Floodplain widths

Soil types

Logs in stream

Ice Damage

Drift locations

Etc

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Site ReconnaissanceSite Reconnaissance Site SurveySite Survey

Center of Stream

Edge of water

Bottom of Bank

Top of Bank

Floodplains

Trail

Utilities

Roads

Drift / Ice damage

Etc

Survey upstream and downstream for 300 ft

Survey approaches on both sides 150 ft

Survey top of banks for 30 ft

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Site ReconnaissanceSite Reconnaissance Geotechnical InvestigationGeotechnical Investigation

Bedrock Loam

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Geomorphology ConcernsGeomorphology Concerns

From Rosgen’s

“Field Guide for

Stream Classification”

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Geomorphology ConcernsGeomorphology Concerns Stream StabilityStream Stability

Bedrock - Type A Channel

Stable Banks – Type B Channel

Deposition Area – Type C Channel

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Geomorphology ConcernsGeomorphology Concerns Bank StabilityBank Stability

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Hydrology and HydraulicsHydrology and Hydraulics Waterway AdequacyWaterway Adequacy

HydrologyHydrology +Regression Equations from USGS Reports on Estimating Frequency and Magnitude of Floods

=

Flow (CFS)

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Hydrology and HydraulicsHydrology and Hydraulics Waterway AdequacyWaterway Adequacy

HydraulicsHydraulics

1) Take CFS from Hydrology

2) Take Site Investigation info

3) Take Site Survey

And

Use a computer model such as

HEC-RAS (River Analysis System)

Or

WinXSPRO

And you get this…..

HEC-RAS Example

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Hydrology and HydraulicsHydrology and Hydraulics Flooding –Spring, Fall or rain on snowFlooding –Spring, Fall or rain on snow

Good or Bad Location?

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Hydrology and HydraulicsHydrology and Hydraulics

ScourScour

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Hydrology and HydraulicsHydrology and Hydraulics Navigational Navigational

ClearanceClearance

5 ft Minimum Required

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AlignmentAlignment HorizontalHorizontal

Straight

90 degree Bend

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AlignmentAlignment VerticalVertical

Slight Grade

Bottom of Sag Curve

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Environmental ConcernsEnvironmental Concerns FisheriesFisheries

Spawning Areas, Fish passageSpawning Areas, Fish passage TES - ClosuresTES - Closures

SalmonSalmon Bull TroutBull Trout Cutthroat TroutCutthroat Trout etcetc

WildlifeWildlife Nesting Trees, Rearing areas, etcNesting Trees, Rearing areas, etc TES - ClosuresTES - Closures

Indiana BatIndiana Bat Bald EaglesBald Eagles Northern GoshawkNorthern Goshawk etcetc

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Environmental ConcernsEnvironmental Concerns Ice FlowIce Flow Floating DebrisFloating Debris Falling TreesFalling Trees Falling RocksFalling Rocks Excessive Snow LoadsExcessive Snow Loads Avalanche ChutesAvalanche Chutes Springs/SeepsSprings/Seeps WetlandsWetlands OthersOthers

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Design LoadsDesign Loads Dead LoadsDead Loads

SuperstructureSuperstructure DeckingDecking RailingRailing Wearing SurfaceWearing Surface Miscellaneous Miscellaneous

Utility LinesUtility Lines CoversCovers

2020


Design LoadsDesign Loads Live LoadLive Load

Pedestrian – Pedestrian – 85 psf85 psf Equestrian Equestrian OHV’sOHV’s SnowmobilesSnowmobiles Mountain BikesMountain Bikes VehiclesVehicles

5,000 width <6 ft5,000 width <6 ft 10,000 6 ft<width<10 ft10,000 6 ft<width<10 ft

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Design LoadsDesign Loads Snow Loads – Snow Loads – 0 psf to over 350 psf0 psf to over 350 psf

SNOTEL sites – SNOTEL sites – 550 to 600 in the West550 to 600 in the West Local Building OfficialsLocal Building Officials http://fsweb.mtdc.wo.fs.fed.us/snow_load/http://fsweb.mtdc.wo.fs.fed.us/snow_load/

Wind LoadsWind Loads OverloadsOverloads

GroomersGroomers 7600# - 18,000#7600# - 18,000#

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Technology & DevelopmentBridge TypesBridge Types

Trail Bridge CatalogTrail Bridge Catalog Forest Service Intranet - Forest Service Intranet -

http://fsweb.mtdc.wo.fs.fed.us/bridges/http://fsweb.mtdc.wo.fs.fed.us/bridges/ Forest Service Internet - Forest Service Internet -

http://www.fs.fed.us/na/wit/WITPages/bridgecatalog/http://www.fs.fed.us/na/wit/WITPages/bridgecatalog/

http://fsweb.mtdc.wo.fs.fed.us/bridges/

http://www.fs.fed.us/na/wit/WITPages/bridgecatalog/

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Technology & DevelopmentBridge Bridge Fabrication/SupplyFabrication/Supply Structure produced by a certified Manufacturer Structure produced by a certified Manufacturer

for the type of material being used.for the type of material being used.- See “Contact Information For Wood and Steel Pedestrian and - See “Contact Information For Wood and Steel Pedestrian and Trail Bridges” at National Wood In Transportation WebsiteTrail Bridges” at National Wood In Transportation Website

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SummarySummary Site ReconnaissanceSite Reconnaissance Geomorphology ConcernsGeomorphology Concerns Hydrology and HydraulicsHydrology and Hydraulics AlignmentAlignment Environmental Concerns Environmental Concerns Design LoadsDesign Loads Trail Bridge WebsiteTrail Bridge Website Questions?Questions?

A Common Sense Approach to Selecting Bridge Sites

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