presenters: mark bouma, p.e. michael bauer, p.e

Presenters:

Mark Bouma, P.E. Michael Bauer, P.E.Technical Oversight Leader North Texas Operations ManagerNorth Texas Tollway Authority Jacobs Engineering

ASCE PresentationSam Rayburn Tollway/US 75 Interchange (Segment 4)

2

3

Milestones & ScheduleMilestones & Schedule

• Approved Schematic – June 2005

• Approved for Tollway Facility in May 2007

• NTTA awarded development rights in 2007

• NTTA awards design contract in 2007:– Segment 4 in October

• Open the Corridor by Jan. 1, 2011

4

Segment 4 Schedule ChallengesSegment 4 Schedule Challenges

• 38 months to open the Corridor– Largest single NTTA construction contract at the time

• Approved schematic– Expensive and presented construction challenges– Different functional goals than for a toll facility

• For success, set goal to let contract by Oct. 2008– 3 months to address schematic– 9 months for complete PS&E– 26 months to open, 31 to complete construction

5

The TEAMThe TEAM

• Corridor Management Team– Corridor Manager – HDR– Design Manager - Halff Assoc. – NTTA Project Delivery Dept. – HNTB

• Schematic and PS&E Team– Jacobs Engineering - Prime– Bridgefarmer & Assoc.– ARS, IEA, STL

6

Interchange Reconfiguration EffortInterchange Reconfiguration Effort

• Identified Alternative that:– Cost Less– Easier to construct in required schedule– Better met functional goals of toll facility– Maintained or improved access w/in ROW

• Staring at daunting schedule

• Need State and Local buy-in– Allen, Fairview, Frisco, McKinney– TxDOT & NTTA

7

Schematic EvaluationSchematic Evaluation

• Enhance Safety through Design & Constructability

• Improve Mobility and Accommodate Growth– Design capacity for high volume movements– Minimize typical congestion conditions (short weaves,

unbalanced ML/FR usage, etc)– Segregation of local and highway traffic– Facilitate local access by ramp locations

• Reduce Capital and O&M Costs

8

Approved TxDOT SchematicApproved TxDOT Schematic

• US75 – 8 lane divided– Space for future HOV lanes– Depressed below grade through interchange

• SH121 – 6 lane divided• Single lane DC Bridges• Long-span steel bridges through interchange• Boxed (signalized) frontage connections

– Texas U-Turns

9

Approved TxDOT Schematic:Approved TxDOT Schematic:

10

• US75 – 8 lane divided– Space for future HOV lanes– Remains at or near current grade

• SH121 – 6 lane divided• Two lane DC Bridges• All bridges pre-stressed concrete• Loop ramp frontage connections • Additional on/off ramps

Proposed Schematic:Proposed Schematic:

11

Proposed Schematic:Proposed Schematic:

12

Interchange Enhancements: SafetyInterchange Enhancements: Safety

• Replaced signalized traffic conflicts with dedicated right turn movements

• Eliminated DC/ML-to-FR conflicts

• Improved merge/weave conditions– Full two lane merge for heaviest DC movements

• Balanced highway and local access movements

• Safety during construction

13

Interchange Enhancements: MobilityInterchange Enhancements: Mobility

• Loop ramps for continuous flow FR movements

• Two lane DCs & full ML merge conditions– Improve through-put– Accommodates long-term traffic demand

• Segregates local traffic from highway traffic– Benefits both– Access is maintained or improved

• Mobility during construction

14

Interchange Enhancements: Value & CostsInterchange Enhancements: Value & Costs

• Material selection reduced Capital and O&M costs

• Reconfiguration reduced costs– Afforded additional improvements for Safety & Mobility

• Context Sensitive Solution– Toll facility attributes– Improved access increases development value– Aesthetics and configuration provide identity

• Design for future capacity– Reduces future construction impacts– Sustained mobility and access

15

Interchange Enhancements:Interchange Enhancements:Get In, Get Out, Stay OutGet In, Get Out, Stay Out

• Proposed Configuration Improves Constructability– Eliminate one level of the interchange– US75 at grade– DC realignment away from interchange core– Natural staging areas– Standardized construction elements for bridges

• Less Commuter impacts during construction– Fewer stages result in fewer traffic adjustments– Use of existing roadways during construction

• Design and Materials promote longevity

16

Design Approach

• Project Segmentation– Design Teams for SRT and US 75– Focus initially on geometric tie-down– Teams run concurrent design

• Essentially an Alternative Delivery Style– Weekly Task Force Meetings– Constant client interaction and collaboration

• Bentley ProjectWise used for coordination and organization of project files

17

Tools & Automation

• Best practices developed and applied– Design Cross Sections

– 3D Modeling• Highly accurate in pinpointing ponding areas• Provided finished grades for structures

– Drainage• Utilized Geopak Drainage.Tools• Utilized excel Macros to insert drainage callouts on P&P sheets

– Quantity Take-offs• Setup of database for all ‘smart’ design elements• Produced accurate numbers in minutes instead of days

18

Review & QA

• Redundant checks employed for critical items– Bridge clearances triple checked

• Spreadsheet calculations• Geopak model cross-check• Inroads model cross-check

• Design Reviews– Peer Review (In-House)– Ongoing Client Reviews– OTS Workshop

19

Construction

• NTTA Construction Manager – KBR

• Contractor - W.W. WEBBER– Bid 65% plans, issued 100% PS&E after award– Low Bid $219.8M– NTP October 23, 2008

• Largest NTTA construction contract at the time

• 2.5 years start-to-finish

• Phased opening with the DC’s being top priority

20

Construction

• Interactive and Collaborative Construction

• Worked Together to further reduce costs– Adjust North Limits on US 75– Change Pavement Section– Build-out two lanes on SPUR 366– Modified phasing to further support construction

• Additional 5-6% in cost reductions realized

21

Photos

22

Photos (cont’d)

23

Photos (cont’d)

24

Photos (cont’d)

25

Photos (cont’d)

26

Photos (cont’d)

27

Photos (cont’d)

28

Photos (cont’d)

29

Construction by the Numbers

• Tallest Point – 80’ (~6 stories)• Concrete used – ~5M ft3; enough for a sidewalk from

Dallas to New Orleans (450mi)• Longest Continuous Bridge – 4,800 ft; length of ~16

football fields• Concrete barriers and rail – ~36mi; enough to stretch from

McKinney to DFW International Airport• Concrete Beams – 24mi worth; laid end-to-end would

stretch from Allen to downtown Dallas• Soil used as fill – ~1.3M yd3; amount which would fill

130,000 dump trucks (lined end-to-end would stretch 620mi from Dallas to St. Louis)

• Sod placed – 75 football fields worth or 1-18 hole golf course

30

THE ENDTHE END

QUESTIONS