1 THE PCI “BIG BEAM CONTEST” – AN EFFECTIVE TEACHING TOOL RICHARD MILLER, FPCI PROFESSOR OF CIVIL ENGINEERING UNIVERSITY OF CINCINNATI CHAIR, PCI RESEARCH AND DEVELOPMENT COUNCIL

2 PCI STUDENT EDUCATION COMMITTEE Committee Goal – To promote the use of precast/prestressed concrete through education, especially at the college and university level. Chair –Sergio Brena, U Mass. PCI Staff Liaison – Alex Morales.

3 HISTORY OF THE COMPETITION PCI had 2 design competitions. –One for architects Students were asked to submit a design in precast concrete. Emphasized “form and function” –One for engineers Students were required to design a structure using prestressed/precast concrete. Emphasized numerical design. Architecture competition drew several entries. Engineering drew only one.

4 SOLUTION! THE PCI BIG BEAM COMPETITION Create teams of students to work with faculty and producer members to design, fabricate and test a precast concrete beam.

5 MOTIVATION Introduce engineering, architecture and technology students to prestressed/precast concrete. To foster co-operation and relationships between students, faculty and PCI Producer Members. Let the students get “hands on” experience. Solve a real problem.

6 OBJECTIVES Fabricate a precast concrete beam. Test the beam. Points will be awarded for performance in various categories. Write a report on design/fabrication - a prize will be awarded for the best report. Make a video! CASH PRIZES! Sponsored by SIKA Corp. –SIKA has sponsored the competition since the academic year. THANK YOU SIKA!

7 WHO CAN PARTICIPATE? Any student enrolled in a 2, 4 or 5 year Baccalaureate Program in: –Civil Engineering/Technology –Architecture –Architectural Engineering/Technology –Construction Engineering/Technology –Construction or Building Sciences/Technology Graduate Students in any of these areas.

8 TEAMS Students work in teams. 5 members recommended but no set rule. Individual entries allowed. Teams may mix graduate and undergraduate students. All teams must work with a PCI Producer Member. PCI Producer Members may work with more than one team and/or more than one school. All teams need a faculty advisor. One advisor may work with more than one team. Joint entries between 2 schools permitted.

9 PRODUCER/MEMBER PARTICIPATION Required unless no P/M can be found to sponsor. –Can get waiver from PCI if no sponsor can be found or none within reasonable distance. Encourages relationship between producers, students, faculty and PCI. Safety –Prestressing can be dangerous.

10 RULES CONCERING PRODUCER MEMBERS Must sponsor teams. May assist with design. Fabrication –Producer/Member decides how much students may do safely. Encouraged to let students help in fabrication. Students should be present during casting. Are responsible for transport and disposal of beam.

FACULTY PARTICIPATION Each team must have a faculty advisor. One advisor may work with multiple teams. Advisor is responsible for aiding the students in design. –Student should do the design work on their own, with faculty and producer member help. Faculty Advisor is responsible for assuring students take proper safety precautions. Faculty Advisor is responsible for testing or making arrangements for testing. Faculty Advisor needs to assure the quality of the final report. 11

12 WHY A BEAM? Easiest element to design in prestressed. –Service load design is strength of materials. –Ultimate is almost the same as RC Must calculate steel stress. –L/d is usually large, shear usually can be controlled with minimum stirrups. Easy to fabricate. Easy to test.

BASIC RULES The students must design a beam to hold a given design load. –Penalties for being under strength or too far overstrength. –Penalty for early cracking. Student must try to predict their results before testing and get points for accurate predictions. 13

BASIC RULES Points awarded for cost, weight and deflection. Entries are awarded up to 5 points for practicality of design. Up to 5 points are awarded for report quality. –Teams must discuss selection/design of concrete mix in report. –A “what we learned” section is required. 14

15 BEAM DIMENSIONS Beam dimensions and span are set each year by the rules committee. In general, the rules do not limit cross section shape. Shear/Bursting/Top Tension reinforcing permitted. Steel bearing plates allowed. Embedded steel shapes not allowed.

CONTEST Beams are tested as 15 foot simple spans –May be no longer than 17 overall Must be prestressed or post-tensioned. Must be flexural members –No arches, trusses, etc. May have any cross section, but must be flat and horizontal on top. Tested with a single point load at midspan (NOTE – load position change.

17 BEAM TESTING – Rules Beams are tested as simple spans with a midspan point load. Target applied load = 30k total Actual applied load must be between 30k and 37k total. Must not crack below 18.75k applied load. Load vs. Midspan deflection is measured.

18 BEAM DESIGN Rules Allowable materials listed in the Rules. All beams must meet the design requirements of the ACI or the PCI Handbook (7 th ed.). (International entries use their national code). Beams may not have brittle failures or fail in shear or bearing before calculated ultimate load is reached. Practicality is a consideration!

19 REPORT Rules Contestants must submit: –Design/Fabrication report. –Beam details and certified pre-test predictions. –Load vs. Midspan deflection graph of the beam. –Test Results. –Concrete properties and discussion of mix. –“What we learned” –Video and photographs of the test so judges can verify the test was done properly. May submit additional video. Results due in June, Judging in July.

Video Contest Students may submit a video of the design, fabrication, and testing. –This is in addition to the required test video. This video should include “What we learned” commentary. Video should be entertaining! Prize for most entertaining video. 20

Prizes Cash prizes for winners –Money must go to students or student organizations! Winning team goes to Convention in Cleveland in March –Guests of Sika –Be sure students provide accurate permanent address so we know how to contact them! Best video posted to web. 21

JUDGING CHANGE RATIONALE Through the 2013/14 contest, entries were judged by PCI Zone. Best in each Zone competed for national title. Originally done to foster “local competition”. Zone entries were uneven; some zones had many entries and some had few. Some lesser quality entries made national final because of lack of entries in a zone.

JUDGING CHANGE RATIONALE In categories of low cost, low weight and largest deflection, points were awarded based on ranking of best to worst. This system does not account for large or small differences between entries. –Example – three beams weigh 100, 101 and 150 pounds; points would be 10, 9 and 8 respectively.

JUDGING CHANGE Starting with 14/15, no more zones – all entries judged in a national competition. –Zone and/or Regional results still available – requested by RMDs. –Top in each Zone guaranteed a prize. Prizes to top in each Zone + 13 next best entries (20 total) Prize value based on national placement.

JUDGING CHANGE Entries receive 10 points for holding between 30 and 37k total load. –(-1) point for each kip above 37k –(-2) points for each kip below 30k –No less than “0” points 5 point penalty for not achieving the cracking load of kips total. (Note: is service load. 1.6(18.75)=30k)

JUDGING CHANGE For lowest weight, lowest cost, largest deflection and best prediction: –The best and worst values in the category will be determined. –Points, rounded down, based on: 10*(your entry – worst)/(best-worst) Judges still award up to 5 points for design quality and up to 5 points for report quality.

27 OPPORTUNITES TO TEACH The Big Beam contest presents a unique opportunity to relate theory and practice. Class project In prestressed course In RC course Senior project Special studies/project.

28 Our Producer Member!

29 Old picture – safety equipment now mandatory!!!

30 OPPORTUNITES TO TEACH Small deflection prior to cracking. After cracking, cracks close on unloading. Large deflection (often L/50) at failure.

31 OPPORTUNITES TO TEACH Introduce beam behavior through testing.

32 The previous slide shows: Linear load deflection to cracking. Increased cracking load. –Definition of cracking Ductile behavior Hysteresis behavior. Opportunity to predict –Cracking load –Ultimate load –Ultimate deflection

33 OPPORTUNITES TO TEACH Introduce beam behavior through testing.

34 The previous slide shows Concrete strain Cracking can be found from this graph as well. If the steel is instrumented –On cracking, the steel strain “jumps” at cracking. –Large strain near failure.

35 OPPORTUNITES TO TEACH Introduce advanced topics –Bearing –Deflection predictions using M-phi relationship –Cross section optimization –Lateral stability –Computer programs

36 M-curvature from Response 1/in

37 Finding Non-elastic Deflection Choose a load. Plot the moment diagram. Plot the curvature diagram.  =  dx For a simply supported beam with a symmetrical loading, use moment area. This can be done numerically.

38 A simple spreadsheet program for moment-area calculations.

39 OPPORTUNITES TO TEACH Practical design/fabrication issues –Fitting the strand into cross-section. –Shear/bursting steel designed to fit without congestion and with proper clearance. –Lifting/transportation. –Mix design for fabrication. –Curing/storage. Tour of fabrication plant

40 OPPORTUNITES TO TEACH Materials issues –Mix Design –Admixtures –Mechanical properties –Special issues Fibers Pozzolans

41 OPPORTUNITES TO TEACH Introduction of the PCI Handbook. –CDs provided to students at low cost. Introduction of prestressed concrete provisions of ACI-318. Students can “shop” the code for most favorable provisions – encourages familiarity with code.

42 SUCCESSES Last year, 30 teams from 20 schools entered. EVERY student team describes the experience as positive AND says they learned something. Students comment that this contest is the MOST useful in terms of learning something they can use. Producers were eager to participate. Promoted prestressed/precast concrete. –Schools have added prestressed courses or for credit projects due to success of contest.

PARTICIPATION THROUGH 2015 No records for 2001 and Approximately 82 different schools have participated in 15 years! Drop after 2009 due to 2008 recession. Several producers went out of business or shut down plants.

44 CONCLUSION The BIG BEAM is a great way to teach students prestressed concrete. Students learn practical, engineering skills from this contest. There is a great opportunity to combine theory and practice.

45 TIME FRAME Official rules and announcement – July Posted to PCI Website Register by March 2016 –Suggested but not necessary to enter. Entries due June 2016 Judging – July 2016 Winners announced - August 2016 Presentation of Awards – Convention March – 2017 – Cleveland OH.

46 To participate: Contact Alex Morales PCI 200 West Adams Blvd. Suite 2100 Chicago IL

47 To find the rules: OR Just go to PCI.org and follow the links under “education”.