GILA RIVER / SACATON ROAD BRIDGE A … RIVER / SACATON ROAD BRIDGE A DESIGNER’S PERSPECTIVE ......

transcript

TACKLING ABC PROJECTSSPOTLIGHT ON SHRP2 RO4

GILA RIVER / SACATON ROAD BRIDGEA DESIGNER’S PERSPECTIVE

Webinar presentation:ABC-UTC at Florida International University (FIU)

January 18, 2018 1:00p-2:00p ESTMark A. Chase, PE

AZTEC Engineering Group, Inc.

Gila River / Sacaton Road BridgeA Designer’s PerspectiveJanuary 18, 2018

Collaboration

Agenda• Where (Project Location / Vicinity)• What (The A,B,C’s)

– Existing & New Bridge– Reasons for Project

• How (The 1,2,3’s)– Design – The Beginning and A New Door…– The Low-Tech Slide System

• Why (The $’s)• A Designer’s Perspective• Questions

Where (Location)

Where (Vicinity)

Gila River“1-Mile Wide,1-Foot Deep”

Sacaton, AZ

Bridge Site

Where (Vicinity)

Gila River“1-Mile Wide,1-Foot Deep”

Sacaton, AZ

Bridge Site

Photo Courtesy of Gila River Indian Community – www.gilariver.org

What (A,B,C’s)Existing Bridge (H145)

• Completed 1961– Replaced original timber bridge

• 4 x 35’ spans – Total Length ~ 140’– 45 Degree Skew

• CIP slab on precast rectangular beams– Plan Alternative – Conventional & Prestressed

• Steel H-Piling (Very Shallow)– Solid Pier Walls and Pile Cap Abutments

• No Approach Slabs or Expansion Joints

What (A,B,C’s)New Bridge (H144)

• Completed Spring 2015– Replaced original concrete slab bridge

• 2 x 70’ spans – Total Length ~ 140’– 15 Degree Skew

• CIP slab on PC/PS AASHTO Type III-Mod• Abut/Pier Caps on Drilled Shafts• Semi-Integral Abutments and Approach Slabs• Expansion Joint – At Pier

What (A,B,C’s)Reasons for Project

• Roadway Safety• Roadway Overtopping• Sufficiency Rating

Roadway Safety

Roadway Overtopping

Sufficiency Rating

How (1,2,3's)Design - The Beginning

• Conventional RFQ / Consultant Selection– Preliminary Engineering / Scoping - 2011– Final Design Phase - 2012

• Design – Bid – Build• Evaluated Typical Bridges & Methods

– Typical Boundary Conditions• No temporary supports in the river• Typical DOT Design & Construction Methods• In our Bridge Selection Report we mentioned ABC• Maintain Traffic ( selected “Approved” Detour)

– phased construction, shoofly detour, full closure alternatives

AADT ~5100

6-MilesEach Way

AADT ~5100

6-MilesEach Way

• Finalized PS&E Package, Clearances, Etc.– Bid Ready

• Challenges Remained…Or Opportunities?– Funding

• Budget ~$2 million < Estimate ~$2.7 million– Maintenance of Traffic

• 4-6 Month Detour remained a concern

• A New Door Opened…

• Finalized PS&E Package, Clearances, Etc.– Bid Ready

• Challenges Remained…Or Opportunities?– Funding

• Budget ~$2 million < Estimate ~$2.7 million– Maintenance of Traffic

• 4-6 Month Detour remained a concern

• A New Door Opened…

How (1,2,3's)…A New Door Opened

• SHRP2 Grant (ABC Toolkit/Techniques)– Opportunity for funding of ABC approach– Opportunity to improve Maintenance of Traffic– Opportunity to accelerate Construction– Grant Received Fall 2013 - $500K

• SHRP2 Grant (ABC Toolkit/Techniques)– Opportunity for funding ABC Approach– Opportunity to Improve Maintenance of Traffic– Opportunity to Speed Construction– Grant Received Fall 2013 - $500K

• Construction Manager/General Contractor (CMGC)– Also known as Construction Manager at Risk (CMAR)

• Contractor selected by Owner based on Qualifications• Guaranteed Maximum Price Negotiated with Owner

– CMGC RFQ / Selection Spring/Summer 2014– FNF Construction Inc., Phoenix, AZ

How (1,2,3's)SHRP2 Toolkit & CMGC

• Worthy of separate Presentations on their own• Key Element of this Project’s success

– Applied FNF’s Construction Methods and Expertise• Lateral Slide was first for entire Project Team• Local, Available Tools / Equipment / Techniques• Keep it Simple

– Construction Cost Modeling vs. Engineering Estimates– Risk Identification During Design (Most Important)– Revisited ENTIRE Design

• Revisited ENTIRE Design – Some Key Items– 15 degree skew / shift bridge North

• Construct new substructure under existing bridge & across existing road, outboard foundations

– Minimize Temporary Works• Reduce “Throw-Away”• Mitigate Risk of River Flows

How (1,2,3's)Skew/Shift Substructure

How (1,2,3's)Minimize Temporary Works

• Temporary Works Cost Money and Time• Temporary Works in River add Risk

– When will the river flow?– Can we mitigate?– Who owns the risk financially?

• Keep it Simple• Use available tools vs. buying/making expensive new ones

• Temporary Support (Pier)

• Permanent “Temporary” Support (Abutment)

How (1,2,3's)The Low-Tech Slide System

• Keep it Simple

• Theoretical (Steel-Steel)– Friction (Static/Kinetic)

• Various Sources– Greasy = 0.1/0.05– Plain = 0.78/0.45

• Actual (Steel-Steel)– Friction (Static/Kinetic)

• Greasy 0.25/0.15

• Take-Away– Plan for higher friction (2x

to 3x)– This is not an operating

room…the grease gets dirty just by the wind and air

– Rusty Steel is “sticky”

• Theoretical (Steel-Steel)– Forces (Static/Kinetic)

• 4-Girder Element– 265K (Reaxn)– 26.5k / 13.25k

• Actual (Steel-Steel)– Forces (Static/Kinetic)

• 4-Girder Element– 258K (Reaxn)– 63K / 36k

• Capacity – 300k

• Take-Away– Plan for higher forces– Planning with excess

capacity is less expensive than finding out you don’t have enough

• Why no “Guides”– No Potential for Binding– Higher friction will control

bridge…won’t “blow away” on its own

• Plan B– Longitudinal Jacking

System– “Steering”

• Take-Away– It Worked…

• Expansion Joint at Pier, Abutments Pinned

Why ($'s)• Some Quick “Figures”

– Total Project Capital Cost (GMP) – $2.7M• $1.1M Bridge = $125/sf

– ABC Costs - ~$0.4M (15%)– Included Allowances/Enhancements - ~$0.3M (8%)

• Paint the Bridge• Add more bank protection• Contingency/Items – River Flows

Why ($'s)• Traffic Impact

– 9 days + 1 weekend vs. 4-6 Months• 14-22 week Saving

– 700K vehicle miles vs. 6M to 9M• 5M to 8M vehicle miles savings

– 3 hours vs. 24 to 36 hours user time• 21 to 33 hours savings per roadway user

– $0.4M vs. $0.9M to $1.4M• ABC Cost vs. Fuel Only Cost• Savings $0.5M to $1.0M

One Designer’s Perspective• ABC = Accelerate Bridge Construction

– Contractor’s input and buy-in is essential for success– CMGC made this possible for this project

• Tailor the complexity to the project – Keep it Simple– Fundamental engineering principles really do work– Use existing tools in new ways

• ABC was once “exotic”, Today it’s everyday– As Engineers, we have been trained to be conservative,

methodical and to think things through, this is ABC– Bridge Design, for me is more about the Bridge Construction

because that is the final measurement of what we accomplish

Time-Lapse Video Link• Time-lapse Video – AZTEC Engineering on YouTube

– Sacaton Bridge Replacement – Accelerated Bridge Construction– https://youtu.be/Auuq_otR6BY

QuestionsPamela Hutton, PESHRP2 Implementation ManagerAASHTOphutton@aashto.org

Mark Chase, PESenior Vice PresidentAZTEC Engineering Group, Inc.mchase@aztec.us

Abutment/Approach Slab

Expansion Joint at Pier

Deck Closure Pour

Diaphragm Closure Pour

Internal Shear Key

Modified AASHTO Type III

GILA RIVER / SACATON ROAD BRIDGE A … RIVER / SACATON ROAD BRIDGE A DESIGNER’S PERSPECTIVE ......

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