Cast-in-Place Concrete Connections for Precast Deck Systems (2011) / Chapter Skim
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C-i Appendix C Phone Survey Results
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C-1 C.1 Introduction to Phone Survey This appendix provides a synthesis of the comments received from the individual respondents who participated in the phone survey that was used to gather information including the respondents' experience with similar systems, their input on important performance criteria, and their feedback on proposed connection concepts. Nearly 60 people were interviewed during the phone surveys which were conducted in partial fulfillment of project Tasks 1 and 2.
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C-2 Table C.1.2: List of Phone Survey Participants First Name Last Name Br idg e E ng ine er M at er ial Sp ec ial ist Fa br ica to r Re se arc he r Ind us try Re p Co nt ra cto r Ot he r Employer Sameh Badie X George Washington U Shri Bhide X X Portland Cement Association Gregg Blaszak X X Tech Fab Hank Bonstedt X PCA Pennsylvania Jimmy Camp X P.E., New Mexico DOT Reid Castrodale X X Carolina Stalite Co. Vijay Chandra X Parsons Brinckerhoff Ned Cleland X Blue Ridge Design, Inc.
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C-3 C.2 Performance Requirements/Specifications The respondents were asked to comment on design/fabrication/construction/performance criteria that must be satisfied to provide adequate performance of key parameters to be included for consideration on this project (listed below)
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C-4 budgets and numerous projects that must be funded. Culmo indicated that it should be noted that rapid construction automatically adds 15-25 percent increase in cost.
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C-5 durability was considered of greatest importance, as it was mentioned by 40 of the 44 individuals who ranked the criteria, and of those, 75 percent of them ranked it as the top priority. Besides durability, other issues considered of great importance were constructability and rapid construction; followed by economy and serviceability/performance.
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C-6 Table C.2.1: Rank ordering of performance criteria Rank Order Durability Strength Fatigue Seismic Constructability Rapid Construction Serviceability/ Performance Economy 1-highest 30 3 1 0 13 9 8 6 2 4 3 1 0 9 8 2 4 3 4 5 1 0 7 3 2 3 4 1 3 2 2 0 0 5 3 5 1 0 2 3 1 3 0 2 6 0 1 0 2 0 2 1 1 7 0 0 1 2 0 0 1 1 8-lowest 0 0 1 0 0 0 0 0 SUM 40 15 9 9 30 25 19 20 % of respondents 91 34 20 20 68 57 43 45 1If the respondents listed multiple performance criteria as equally important, those criteria were given the same ranking (e.g., if durability and strength were selected as top choice, they would both be designated with a "1," the next choice would be designated "3"…there would not be a listing with a "2" for that example)
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C-7 General comments associated with performance criteria The following is a list of comments which amplify the respondents ranking. The comments are ordered alphabetically by State DOTs, followed by alphabetical listing of other respondents.
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C-8 Zeldenrust (WSDOT) listed performance/durability high on the list.
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C-9 The system has to be easy to use and result in reduction in labor if trying to compete with CIP [Ronald]
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C-10 With regard to durability, Tang (NYDOT) suggests a "nested system" approach (i.e., epoxy-coated bar or stainless steel with HPC)
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C-11 potential problems orienting the pieces in the field. In the range of 50-60 ft., FL is using the NE inverted Ts.
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C-12 The PD system looked like much more work in field compared to double-Ts with weld plates that SD is currently using [Johnson]
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C-13 Eriksson stated that the section seemed highly erectable and efficient; the drawback was the large amount of CIP. Gokhale, who participated in the PD showcase, did not see any advantage of this system to voided slabs.
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C-14 dropped into the joint which would make it easier for the longitudinal bars to be tied in place. [Although, note that currently, the longitudinal bars are dropped in place in a prefabricated cage.]
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C-15 system. He did not think that it mattered whether or not the top of the bottom flange was rough or smooth because any crack that would form should be arrested by the reinforcement.
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C-16 Nickas did not recommend using voids because the forms float and end up costing more than a solid slab. Sennour also thought that voids could be problematic because of floating.
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C-17 C.5 Comments on Longitudinal and Transverse Connection Concepts between Precast Panels and Bulb-T Flanges Survey respondents provided some general comments on longitudinal and transverse joint connection concepts. These comments are summarized first, followed by comments specific to the five joint connection concepts identified in the survey: loop bar (U-bar)
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C-18 trying to eliminate for years. The place for these systems is with rapid construction.
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C-19 Looped bar (U-bar) detail (5a)
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C-20 that it performed well. For the loop bar detail shown in the survey (Fig.
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C-21 (USFS) also indicated the longitudinal bars would need to be flexible to fit into the system.
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C-22 Headed bar detail (5c) Several respondents thought the headed bar detail had promise and preferred it over some of the other details.
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C-23 that both this and the headed bar detail would be hard to line up. Hartmann was concerned with the legs of the shear key potentially breaking off with this detail as well as in the cases of the other concepts.
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C-24 C.5.3 Comments on Common Issues of Concern with Connection Concepts Spalling of lip of joint (5a) Ronald, Smith, and Tang had concerns that the thin lip of concrete forming the bottom of the joint may spall; Smith stated that construction ease associated with butting the adjacent flanges is not worth the risk.
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C-25 or if longer life is needed, or if where it would be costly to shut down the bridge. AK has used galvanized steel and had discussions regarding stainless clad steel.
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C-26 C.6.2 Fiber Reinforced Polymer (FRP) Reinforcement Bhide recommended looking at nonmetallic reinforcement in the systems.
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C-27 Gulyas (former chair of ACI 223 Shrinkage-Compensating Concrete) has had a great deal of experience with grouts and epoxies including magnesium ammonium phosphate.
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C-28 also be an option. Meinheit strongly cautions against using grouts with significantly different properties from the adjacent precast concrete (e.g., modulus of elasticity)
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C-29 gravel instead of cement material. Adding fibers to the grout might help reduce cracking at places other than the interface.
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C-30 poured all the way to the top, but would have a sealant on top; however, this then becomes a maintenance issue. Kaufman's suggestion was to provide a ¾ in.
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C-31 rideability would be problem without grinding.
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C-32 decks to meet contract obligations. Castrodale indicated that the ability to remove differential camber is important to rideability.
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C-33 20 degree; he indicated consideration should be given regarding how to place/connect panels (i.e., parallel to skew or use trapezoidal sections at ends)
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C-34 Ralls indicated UTDOT will use a new system as long as the cost does not exceed 30 percent more than the conventional method. IBRC/IBRD funds are a way to get innovative projects built.
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C-35 Ronald identified road blocks in the code to getting precast deck systems to be economical. These include AASHTO recommendations for cohesion and shear friction mechanisms for load transfer across the panel (e.g., shear studs placed at less than 2 ft.
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C-36 moment issues. Castrodale mentioned Miller's NCHRP project (5-19)
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C-37 In TX, they carefully tried to address color difference between grout and precast in Waco bridge. They were not successful.
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