Recent Guideline Changes1

Recent AT Guideline Changes

• Existing Documents

• New Technical Documents

• Bridge Structure Design Criteria

• Bridge Design Bulletins

• Bridge Best Practice Guidelines

• Roadside Design Guide

Recent Guideline Changes2

Existing Documents

• Hydrotechnical Design Guidelines

• Bridge Size Culvert Design Guidelines

• Culvert Sizing Considerations

• BPG # 7 – Spread Footing

Recent Guideline Changes3

New Technical Documents

• Context of Floods in Alberta

• Flood Envelope Curve Analysis

• AT Open Channel Flow Equation

• Alberta Rainfall Runoff Analysis

Recent Guideline Changes4

Bridge Structure Design Criteria

• Section 4e – Bridge Fills– No more CB6-2.3M22– Headslope tool – elliptical fill transition– Bridge Fill Width = Gross Width + 2m– Fill taper rate – max. 30:1

• Section 4b – Min. Bridge Grade– Target minimum = 1% (drainage)– Every effort for 0.5% min. grade

Recent Guideline Changes5

Bridge Design Bulletins

• BD # 5 – Retaining Walls near Rivers– Issues :

• Erosion - outflank/undermine• Failure – little warning, catastrophic• Repair – extensive, expensive• Inspection – specialized, systematic• Flexibility – accommodate future stages?

– Recommendation :• Consider Other Options• Design – RPW, piling, structure mod.

Recent Guideline Changes6

Bridge Best Practice Guidelines

• BPG # 9 – Rock Protection

• Typical details

• Why preferred option

• Bio – not at bridges

Recent Guideline Changes7

Roadside Design Guide

• Bridge Width (Section H5.4.1) :– Min. Bridge Clear Roadway = 9.0m– Match Road Design Clear Roadway– > 9000 AADT, shoulder = 3.0m– Max. shoulder width = 4.0m**– Urban – TAC shy distance (T3.1.6.4)

** Maximum for ring road structures is 3.5 m based on safety audit for AHD SW

Recent Guideline Changes8

Roadside Design Guide

Fig. H7.1 (Underpass Clearance)

Recent Guideline Changes9

Roadside Design Guide• Section H9.2 – Pedestrian/Cyclist

– Rural – shoulder OK– Systems Interchange – no pathway/sidewalks– Pathways ( TAC bidirectional multi-use min. ) –

4.2m wide on structure ( 3.0 plus shy dist. )– WOL + Sidewalk (2.5m wide) typical on low

speed/volume arterial bridges

*** NOTE: warrants for supplemental urban planned facilities beyond basic in urban areas currently under review

Recent Guideline Changes10

Future Guidelines/Clarifications

• Vertical clearances – Pedestrian Structures

• Parallel versus tapers on urban bridges• Use of retaining walls on high speed

roadway bridges• Maximum/minimum grades/crossfalls on

bridges• Combined effects of horizontal and vertical

geometry on ramp bridges