Presentation by Neel Khosa given during the Post-Tensioning Institute's 2011 Technical Conference. Topic is about the use of unbonded post-tensioned concrete in Target Field stadium, home of the Minnesota Twins MLB team.

1. TARGET FIELD MINNESOTA TWINS Post-Tensioning “Design and Construction” May 3, 2011 Neel Khosa, AMSYSCO Inc.

2. 1st Inning : Project Background 2nd Inning : Construction Team 3rd Inning : Design 4th Inning : Post-Tensioning

3. 5th Inning : Coordination 6th Inning : Construction 7th Inning : Sustainability 8th Inning : Stadium Highlights 9th Inning : Grand Opening

4. Project Background Minnesota Twins shared the Metrodome with Minnesota Vikings 1995 : Early plans to move 2005 : Deal between MN Twins and local Govt. 2006 : Minnesota state Govt. approved deal 2007 : Funding finalized and land acquired 2007 : Groundbreaking Minnesota Twins vs. Boston Red Sox Opening Day box score on April 12, 2010

5. Project Background Open Air Ballpark

6. Project Background Form Follows Function Ballpark naming rights to Target Corporation

7. Construction Team

8. Construction Team Owner(s) Minnesota Ballpark Authority Hennepin County Architect(s) Populous HGA Structural Engineer Walter P. Moore Construction Manager Mortenson Construction Post-Tensioning Supplier AMSYSCO Inc. Post-Tensioning Installer E&J Rebar

9. Design of P.T. Flat-plate Post-Tensionedsystem in Mezzanine level. Post-Tensioned girdersin Concourses and some seating areas (with conventionally reinforced pan-formed beams and slabs).

10. Design of P.T. Post-Tensioning selected due to long-span capabilities and reducing concrete depth. Heaviest Girder had 5,805 kips of Final P.T. Force. Many girders required stage-stressing. … “Site limitations and the ballpark layout dictated 28 main grandstand columns to be located directly atop the transit rail lines, so they were transferred with stage-stressed, post-tensioned girders that span up to 45 feet over the corridor to support the ballpark above.” - Justin Barton (Walter P Moore)

11. …

12. … EXAMPLE OF STAGE-STRESSING IN BEAM SCHEDULE

13. Post-Tensioning SYSTEM 0.5” Diameter 270 ksi PC Strand. Unbonded 50 ML HDPE plastic-sheathing. Encapsulated anchorage system for corrosion-protection. REQUIREMENTS Stressing to 33 kips when concrete reached 3000 psi compressive strength. Elongation range ±7% P.T. Supports at 48” o.c.

14. Example of Anchor Detail which illustrates the stage-stressing sequence of a transfer girder.

16. Irregular column layout

18. Most girders were stage-stressed while upper levels were poured.

19. Supported main pedestrian walkway within ballpark.

21. Supported secondary pedestrian walkway

24. Why Coordination?

25. Coordination North/South P.T. girders (in orange) poured and stressed first in order to build upper levels. N/S girders required pockets to sleeves E/W tendons. East/West P.T. beams (in green) and mild-reinforced beams poured second.

26. Construction In order to meet Opening Day 2010, Construction had to start before Design was completed. Target Field was built over a BNSF Railroad corridor. Post-Tensioning eliminated the need for re-shoring which kept the railroad operational during construction.

27. Construction Project finished 3 months ahead of schedule. TIME-LAPSE VIDEO of the construction of Target Field on YouTube. Post-Tensioning was used as a cost-effective construction method. Target Field’s seating was built in several phases.

28. Target Field was the 2nd MLB stadium to receive LEED certification. Earned 36 points towards LEED Silver status. Over 30% of construction materials were made from recycled content. 70% of construction waste was recycled or diverted locally. Sustainability

29. … Sustainability

30. Stadium Highlights

31. Stadium Highlights

32. Grand Opening …

33. Grand Opening Minnesota Twins beat the Boston Red Sox 5-2 on April 12, 2010

34. Grand Opening

35. Grand Opening …

36. Grand Opening …

37. Credits Sources Project Background : http://en.wikipedia.org/wiki/Target_Field Target Field rendering : http://www.minnesota.twins.mlb.com/min/ballpark/ Time-Lapse Video : YouTube via BenjaminLee Palmer Sustainability Facts: http://2ndgreenrevolution.com/2010/04/12/twins-target-field-receives-leed-certification/ Stadium Highlights : http://www.minnesota.twins.mlb.com/min/ballpark/ Box Score (MN vs. BOS on April 12, 2010) : http://sports.yahoo.com/mlb/preview?gid=300412109 Quotes Highlights Images – Logos AMSYSCO : http://www.amsyscoinc.com/index.php Minnesota Twins : http://www.minnesota.twins.mlb.com Mortenson Construction : http://www.mortenson.com/ Populous: http://www.populous.com/ Target Field : http://en.wikipedia.org/wiki/File:TargetField.PNG Walter P Moore : http://www.walterpmoore.com/ Images – Photos Target Field, Coordination, Sustainability, Grand Opening : Neel Khosa on April 3, 2010 (MN vs. STL) Project Background : HOK/Populous Metrodome : http://www.worldstadiums.com Scoreboard: http://www.daktronics.com Seating Profile, Stadium 3D Diagram : http://minnesota.twins.mlb.com/min/ballpark/ballpark_features.jsp

38. THANK YOU !!!