05 Lehr PPT

D F I - C S C E F a l l S e m i n a rG e o t e c h n i c a l E n g i n e e r i n g a n d D e s i g n - B u i l d S E P T E M B E R 1 3 , 2 0 1 3

Overland Bridge Design-Build

Achieving Best Value Through Effective Collaboration Between Designer, Geotechnical

Engineer, and Contractor

Achieving Best Value ThroughAchieving Best Value Throughugh EE veEffectivetiEffectiEffecEffecOverland Bridge Design-Build



Design-Build is the Future

2012 2008

$784 Million

$1.1 Billion 59 D/B Contracts,

17 D/B Contracts

Increase in FDOT D/B Projects


Achieving Best Value

Learning Objectives

1 2 4 3 Project

Understanding FDOT

Design-Build Process

Partnerships & Collaboration

Innovative Solutions

Project Understanding














EAST WEST CENTRAL

Focus Regions










FDOT Adjusted Score Based Selection Process

Phase I Phase II Price Proposal

Average Number of ELOI Submissions Per Project = 7.1 D/B Teams submit an Expanded Letter of Interest (ELOI)

FDOT provides each team with their detailed technical score and comments, Teams have 2 days to elect to proceed to Phase II

Average number of responsive firms selecting to proceed to Phase II = 4.8







Average number of firms submitting a Technical Proposal per project= 4.5

Final RFP Issued Alternative Technical Concept Meetings D/B Teams submit Technical Proposals

Contractor presents for “page turn” Meeting FDOT holds “Q&A” Meeting with Contractor







Bid Price Proposal Phase I + Phase II Scores

= Adjusted Score

*The firm with the lowest adjusted score will be selected.

FDOT pays stipends to D/B firms receiving top two numerically highest ELOI Scores

Average number of D/B Team’s submitting a price proposal per project = 4.5





Partnerships and Collaboration





Partnerships and Collaboration





WEST

N

Innovative Solutions – West Region





Innovative Solutions – West Region

Existing Condition D/B Concept

Single Column/Shaft Widening

Statnamic Testing Program





Fuller Warren Bridge Widening

• Single Column / Single Shaft Substructure Units.

• Non-Redundant Foundations • One SPT boring per shaft. • Additional pilot holes at each shaft. • Additional shaft inspection criteria. • Reduced resistance factor in design.

• Eliminated 51 shafts compared to redundant foundation alternative.





Fuller Warren Bridge Widening

• Increased shaft diameter. • Increased placement tolerance.

• Geotechnical Engineer worked to balance increased shaft diameter with shallower tip elevation.

• Statnamic Testing. • Resistance Factor increased

from 0.5 to 0.6. • Three tests performed for

2,600LF of foundation work.





Innovative Solutions – Central Region

CENTRAL

N





Innovative Solutions – Central Region


Avoided Foundation Conflicts

Utility Tunnel Extension






• Three Sided CIP Tunnel under I-95. • Constructed in 1958. • Founded on timber piling.

• 25LF extension on North side.

• Adjacent to TV Station. • Vibration concerns.






• Micropiles selected for extension.

• Engaged specialty contractor during design phase.

• Collaborative effort to develop size of piles, details and specifications.

• 10 – 8” Diameter Micropiles.

• 106 TN Nominal Bearing Capacity.





Overland Bridge

Existing Foundations D/B Concept

Existing bridge foundations New construction

New abutment and pier locations avoid conflict and eliminate 214 pile extractions





Overland Bridge

• Initial Geotechnical Analysis recommended production pile lengths ranging from 40LF to 56LF.

• Required Driving through Weathered Limestone Layer.

Hard Driving Expected





Overland Bridge

• Actual Driving: • WOH for 15LF to 20LF. • Practical refusal at

hard limestone layer.

• Structural engineer and geotechnical engineer collaborate to complete lateral stability analysis and eliminate need for drilling.

Hard Driving Expected





Innovative Solutions – East Region

EAST

N





Innovative Solutions – East Region

Proposed Pier in Median of I-95


Modified Footings to Eliminate Need for Pre-Drilling





Ramp K Flyover – Median Pier

Existing ExistingProposed

New Ramp

Maintain Access






Example of Skewed Pier Detail of Skewed Pier






I ti

• Footing skewed relative to ramp baseline to fit inside allowable work zone.

• Pile lengths limited by crane capacity.

• Full Dynamic Testing (PDA) used to minimize number of piling. • Phi increases from 0.65 to 0.75. • 410TN vs. 366TN NBR Value.





Ramp K Flyover – Post-Design Effort

vative

• Corner tension piles required considerable embedment.

• Lateral stability analysis required minimum tip elevation.

• Excessive drilling was needed to achieve required tip elevations.

• Redesigned footing, add 8 piles. • 364TN vs. 265TN NBR Value.

• Similar modification underway for nearby Ramp J Flyover footings.

More Hard Driving Conditions


Thank You


05 Lehr PPT

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