bridge pier protection from impact.pdf

8/14/2019 Bridge Pier protection from impact.pdf

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Pier Protectionier Protection

LRFD Bridge Design WorkshopLRFD Bridge Design Workshop

June 12, 2007June 12, 2007

Angel M. Staples, P.E.Angel M. Staples, P.E.

Bridge DesignerBridge Designer


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Structure Protectiontructure Protection


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Substructure Protectionubstructure Protection


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MnDOTnDOT Bridge Officeridge OfficeSubstructure Protectionubstructure ProtectionPolicyolicy

AASHTO Provisions are overly restrictive:AASHTO Provisions are overly restrictive: Not accounting for the followingNot accounting for the following

Probability of vehicle collisionProbability of vehicle collision

Amount of truck trafficAmount of truck traffic

Traffic speedTraffic speed


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MnDOTnDOT Bridge Officeridge OfficeSubstructure Protectionubstructure ProtectionPolicyolicy AbutmentsAbutments

Due to the existence of soil behind abutmentDue to the existence of soil behind abutmentwalls, abutments are not affected by the collisionwalls, abutments are not affected by the collision

load and are considered exempt from meeting theload and are considered exempt from meeting the

substructure protection requirements.substructure protection requirements.


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Pier Protection Policyier Protection Policy Applicable Cases:Applicable Cases:

Piers of New Bridges Spanning RoadwaysPiers of New Bridges Spanning Roadwayswithwith Low RiskLow Risk of Vehicle Collisionof Vehicle Collision

Piers of New Bridges Spanning RoadwaysPiers of New Bridges Spanning Roadwayswithwith Normal to High RiskNormal to High Risk of Vehicle Collisionof Vehicle Collision

Piers of NewPiers of New Bridges Spanning RailwaysBridges Spanning Railways

Piers ofPiers of Bridges Being Rehabilitated orBridges Being Rehabilitated orReconstructedReconstructed


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Pier Protection Policyier Protection PolicyContd)Contd) Specific Design GuidelinesSpecific Design Guidelines

Test Level 5 Barrier ProtectionTest Level 5 Barrier Protection

Application of Vehicle and RailwayApplication of Vehicle and Railway

Train Collision LoadTrain Collision Load

FoundationsFoundations


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Pier Protection Policyier Protection PolicyContd)Contd)


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Low Risk of Vehicle CollisionLow Risk of Vehicle Collision

Sufficient Redundancy (3+ Columns)Sufficient Redundancy (3+ Columns)

Low design speeds (Low design speeds ( 40 mph)40 mph)

OROR

Sufficient Redundancy (3+ Columns)Sufficient Redundancy (3+ Columns)

Design speed > 40 mph AND not on theDesign speed > 40 mph AND not on the

Natl Hwy System AND ADTTNatl Hwy System AND ADTT 500500


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Piers of New Bridges with Normal to HighPiers of New Bridges with Normal to High

Risk of Vehicle CollisionRisk of Vehicle Collision

Pier within 30 of the edge of the nearestPier within 30 of the edge of the nearest

lanelaneDepending on your situation, You haveDepending on your situation, You have

optionsoptions


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Piers of New Bridges SpanningPiers of New Bridges Spanning RdwysRdwys with Normal to High Risk ofwith Normal to High Risk of

Vehicle CollisionVehicle Collision ((MnMn/DOT Bridge Office Substructure Protection Policy)/DOT Bridge Office Substructure Protection Policy)

RequirementRequirement Single ColumnSingle Column

PierPier

TwoTwo--ColumnColumn

PierPier

ThreeThree--ColumnColumn

PierPier

Protect with a 54 high TLProtect with a 54 high TL--5 barrier placed within 105 barrier placed within 10

from the face of the pier.from the face of the pier.

Provide columns with an area greater than 30 ft perProvide columns with an area greater than 30 ft per

column (based on AREMA heavy constructioncolumn (based on AREMA heavy construction

requirements) and design individual columns for arequirements) and design individual columns for a

400 kip collision load.400 kip collision load.

Design for a 400 kip collision load by utilizing a crashDesign for a 400 kip collision load by utilizing a crash

strut. (See Figure 1., also see detailing requirements)strut. (See Figure 1., also see detailing requirements)

NotNotApplicableApplicable

Design individual columns for a 400 kip loadDesign individual columns for a 400 kip load

NotNot

ApplicableApplicable

NotNot


Validate that the structure will not collapse byValidate that the structure will not collapse by

analyzing the structure considering removal of anyanalyzing the structure considering removal of any

single column. Consider all dead load with a 1.1 loadsingle column. Consider all dead load with a 1.1 load

factor. Use live load only on the permanent travelfactor. Use live load only on the permanent travel

lanes, not the shoulders, with a 1.0 load factor. (Forlanes, not the shoulders, with a 1.0 load factor. (Forspecial situations.)special situations.)

NotNot


NotNot



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Pier Protection Policyier Protection PolicyContd)Contd) Piers of New Bridges Spanning RailwaysPiers of New Bridges Spanning Railways

Piers within 50 of the centerline of RRPiers within 50 of the centerline of RR

tracks:tracks:

Shall meet the requirements forShall meet the requirements for Piers of NewPiers of NewBridge SpanningBridge Spanning RdwysRdwys with Normal to Highwith Normal to High

Risk of Vehicle CollisionRisk of Vehicle Collision

Piers within 25 of centerline of RR tracks:Piers within 25 of centerline of RR tracks:In addition to the above requirement, shall alsoIn addition to the above requirement, shall also

meet AREMA 2.1.5.1meet AREMA 2.1.5.1


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Pier Protection Policyier Protection PolicyContd)Contd) Bridges Being Rehabilitated orBridges Being Rehabilitated or

ReconstructedReconstructed

the decision whether to upgrade piers to meetthe decision whether to upgrade piers to meet

protection requirements will be made on aprotection requirements will be made on acase by case basiscase by case basis


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Pier Protection Policyier Protection PolicyContd)Contd) Specific Design Guidance:Specific Design Guidance:

Requirements for Test Level 5 BarrierRequirements for Test Level 5 Barrier

ProtectionProtection

can be tied into a concrete roadwaycan be tied into a concrete roadwaypavement or shoulderpavement or shoulder

can consist of a standcan consist of a stand--alone barrier on aalone barrier on a

moment slabmoment slab


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Pier Protection Policyier Protection PolicyContd)Contd)Test Level 5 Barrier ProtectionTest Level 5 Barrier Protection


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Pier Protection Policyier Protection PolicyContd)Contd) Specific Design Guidance (Contd):Specific Design Guidance (Contd):

Requirements for Application of Vehicle andRequirements for Application of Vehicle and

Railway Train Collision LoadRailway Train Collision Load

Apply the load in a horizontal plane 4 feet aboveApply the load in a horizontal plane 4 feet abovethethe groundlinegroundline

Assume the load can act on the pier at any angleAssume the load can act on the pier at any angle

up to a maximum of 30 degrees from theup to a maximum of 30 degrees from thedirection of the roadway or railway tangentdirection of the roadway or railway tangent


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Pier Protection Policyier Protection PolicyContd)Contd) Specific Design Guidance (Contd):Specific Design Guidance (Contd):

Foundation RequirementsFoundation Requirements

Spread footing and pile/drilled shaft foundationsSpread footing and pile/drilled shaft foundationsare considered adequate to resist the lateralare considered adequate to resist the lateral

collision loadcollision load

Are exempt from analysis when the otherAre exempt from analysis when the otherrequirements of this policy are metrequirements of this policy are met

Why? Passive soil pressure, friction, pileWhy? Passive soil pressure, friction, pilestructural capacity, unusual displacement understructural capacity, unusual displacement underextreme event limit state is ok as long asextreme event limit state is ok as long ascollapse is avertedcollapse is averted


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MnDOTnDOT Bridge Officeridge OfficeSubstructure Protectionubstructure ProtectionPolicyolicy

Impetus for developing this policyImpetus for developing this policyAbutmentsAbutments

PiersPiersVarious CasesVarious Cases

Design GuidelinesDesign GuidelinesFor more information:For more information:

Just Ask Dave Dahlberg, 651Just Ask Dave Dahlberg, 651--366366--44914491

bridge pier protection from impact.pdf

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