69th Annual Concrete ConferenceFinal Program

7:00 a.m. | Registration and Continental BreakfastModerators: Mike Hemstad, Short Elliott Hendrickson, Inc.; Rachel Detwiler, Beton Consulting Engineers

8:00 | Welcome Carriage HallMike Hemstad, Short Elliott Hendrickson, Inc.

8:10Lessons Learned from Structural FailuresRandall Poston, Pivot Engineers, American Concrete Institute, Purdue University College of Engineering

The goal of any investigation of a structural failure is to determine the probable cause(s), with the end result being able to instruct the industry so that it does not happen again. Through years of investigating many different types of structural failures, some common threads have been observed. This presentation will discuss several case studies of structural failures and some of the common threads that have been observed in seemingly different types of failures, and we will summarize the lessons that have been learned.

9:00Allegiant Stadium (Las Vegas Raiders) Construction Aaron Calhoon, Mortenson | McCarthy Joint Venture

The Las Vegas Stadium will provide a world-class home for the NFL Raiders upon the team’s relocation in 2020. The Mortenson | McCarthy joint venture team will build the $1.9 billion domed stadium, which will also host UNLV Football and a variety of other sporting and nonsporting events. The facility will feature 65,000 seats (expandable to 72,000), a retractable natural turf field, large operable walls that open to spectacular views of the neighboring Las Vegas Strip, and a variety of premium spaces throughout all levels.

9:45 | Break

10:15New ACI Code Provisions on Hooked & Headed Reinforcing BarsDavid Darwin, Department of Civil, Environmental, and Architectural Engineering, University of Kansas

The new development length requirements in ACI 318-19 for hooked and headed bars are based on test results that include bar stresses at failure up to 153,000 psi and concrete compressive strengths up to 16,500 psi. Development lengths for hooked and headed bars are now functions of bar diameter to the 1.5 power and an approximation of concrete strength to the 1/4 power for compressive strengths below 6000 psi. The new provisions permit larger obstructions and closer spacing of headed bars than ACI 318-14. Requirements for cover, spacing, and confining reinforcement are redefined.

11:00Understanding and Preventing Incompatibility of Concrete Mix ComponentsTim Cost, V. T. Cost Consulting, LLC

As concrete materials and mix designs become more diverse and complex, the potential for severe incompatibility of materials becomes much greater. Extremely delayed setting, severely attenuated early strength gain, rapid slump loss, and even flash set are some of the abnormal behaviors that can result when incompatibility strikes—and predicting it can be quite elusive. This presentation will review the conditions and influences responsible for such issues and present precautionary best practices as well as simple protocols for evaluating and minimizing the potential for incompatibility as well as the resolution of related field issues.

11:45Concrete Award Presentation2019 Award Presented to Professor Carol Shield, CSE Distinguished Professor, University of MinnesotaCarol has served on the concrete conference planning committee in the past. She has also been a recent conference speaker: she gave a presentation on Fiber-Reinforced Polymer (FRP) reinforcement two years ago. She has been an active member in the concrete community. She has served on ACI 440 for a number of years, including service as Chair. She is currently leading the effort to develop a parallel ACI 318 code for FRP reinforcement. Additionally, she has done extensive research in reinforced and prestressed concrete. She has taught the prestressed concrete class and introduction to concrete class at the U of M Twin Cities for several decades.

Presented by: Cathy French, University of Minnesota

December 5, 2019Earle Brown Heritage Center, Brooklyn Center, MN

Sponsored by: College of Continuing and Professional Studies, University of MinnesotaDepartment of Civil, Environmental, and Geo- Engineering, College of Science and Engineering, University of Minnesota

Noon | Lunch Garden City Ballroom and HarvestModerators: Sara Nelson, Olson & Nesvold Engineers, PSC;Amy Trygestad, Chase Engineering, LLC

1:00 p.m.Construction Planning for Successful Concrete ProjectsRon Steinberger, Mike Johnson (retired), and Michael Martin, McGough; Joshua Edwards, AVR, Inc. and Affiliates

Project planning is a bridge between the experiences of past projects and proposed actions to produce favorable results in the future. It can also be said that it is a precaution by which we can reduce undesirable effects or unexpected happenings and thereby eliminate confusion, waste, and loss of efficiency. Project planning involves prior determination, specification of factors, possible effects, and the relationships necessary to reach the desired goals. This presentation will step the audience through a few project case studies to show how detailed planning and supplier relationships make a huge difference in the outcome of the project.

1:452020 Construction and Cement OutlookEdward Sullivan, Portland Cement Association

If you’re looking for hints on the future of the real estate pipeline, including new residential and nonresidential starts, you can do worse than listening to Ed Sullivan. The senior vice president and chief economist of the Portland Cement Association will discuss the future of cement consumption and concrete construction in the United States.

2:30 | Break

Track A Carriage Hall AModerators: Joshua Edwards, AVR, Inc. and Affiliates;Justin Lashley, Cemstone Engineering Services

3:00Control and Prevention of Cracking in Concrete FlatworkTim Cost, V. T. Cost Consulting, LLC

Cracking of slabs and pavements is perhaps the most common issue in concrete construction and can be the source of owner complaints, held up payments, and even litigation. This is unfortunate when the great majority of such issues are entirely preventable. This presentation will review the most prevalent influences on cracking, including those related to design, materials, environmental conditions, site preparation, and construction methods and sequences. Each of these will be discussed, as well as some simple tools and indicators for monitoring cracking potential.

3:45Evaluating Mix Design Submittals for High Performance Floors & PavementsBryan Birdwell, Structural Services, Inc.

Having optimized concrete materials and mixes for regular project floors and pavements is always important, but doing so for high-performance slabs, including those for high-volume fibers or close tolerances, is essential to achieving the desired results. Mix design submittals often have both insufficient useable information and much superfluous data. This seminar will discuss the critical items needed. Considerations will be given for evaluating the materials, such as the available aggregates, cement, supplementary cementitious materials, admixtures, concrete plant, etc. Various mix analysis methods will be presented to analyze and evaluate the original submitted mix design and come up with reasonable proposed changes if appropriate.

Track B Carriage Hall BModerator: Michael Murphy, Wiss, Janney, Elstner Associates, Inc.

3:00UHPC: A Solution for Today and TomorrowBen Graybeal, Federal Highway Administration, Turner-Fairbank Highway Research Center

Ultra-high performance concrete (UHPC) has emerged as a compelling solution that addresses a suite of challenges and opportunities in the bridge sector. This class of concrete offers enhanced mechanical properties and exceptional durability, thus enabling UHPC to be used for anything from field-cast connections to rehabilitative bridge deck overlays to pre- and post-tensioned superstructure elements. With more than 200 bridges containing UHPC connections having been constructed from coast to coast in the past decade, state DOTs have become aware of the behaviors and advantages of this high-end fiber-reinforced concrete containing a discontinuous pore structure. The presentation will provide an overview of UHPC and a window into the current state of the practice. The presentation will conclude with a look toward a future wherein UHPC is a commonly deployed solution that delivers efficient construction and a long service life.

3:45Lessons in Galvanic Cathodic Protection from Soldier Field and the Franklin Avenue BridgeArne Johnson and John Lawler, Wiss, Janney, Elstner Associates, Inc.

A presentation on lessons learned in using galvanic cathodic protection and the design factors that must be considered to achieve long-term corrosion protection of concrete. Two examples of concrete repairs involving galvanic cathodic protection (Soldier Field in Chicago and Franklin Avenue Bridge in Minneapolis) will be presented to illustrate the lessons learned.

4:30 | AdjournCONTINUING EDUCATION UNITS (CEUs)This conference awards 0.65 University of Minnesota, College of Continuing Education CEUs to those attending all sessions. One University of Minnesota, College of Continuing Education CEU is defined as 10 contact hours of participation in an organized continuing education experience under responsible sponsorship, capable direction, and qualified instruction. A CEU certificate will be sent to each participant after the conference. A permanent record of CEUs earned will be maintained by the University of Minnesota Admissions and Record Transcript Office.

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