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05694aam a2200613Ic 4500 001 F4B580F0B7CA11EC864CB83724ECA4DB 003 SILO 005 20220409010100 008 150929s2015 iauado fsbt s000 0 eng d 035 $a (OCoLC)922541708 040 $a UIG $b eng $e rda $c UIG $d SILO 088 $a InTrans Project 13-469 088 $a IHRB Project TR-660 100 1 $a Phares, Brent M., $e author. $u Iowa State University. 245 10 $a Investigation of Negative Moment Reinforcing in Bridge Decks $c Brent M. Phares, Sameera Jayathilaka, and Lowell Greimann 264 1 $a Ames, Iowa $b Institute for Transportation, Iowa State University $c 2015 300 $a xiv, 96 pages (112 pages in PD file) $b illustrations, charts, photographs (chiefly color) 500 $a September 2015-- Technical Report Documentation Page 504 $a Includes bibliographic references (pages 75-76) 513 $a Final Report 520 3 $a Multi-span pre-tensioned pre-stressed concrete beam (PPCB) bridges made continuous usually experience a negative live load moment region over the intermediate supports. Conventional thinking dictates that sufficient reinforcement must be provided in this region to satisfy the strength and serviceability requirements associated with the tensile stresses in the deck. The American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) Bridge Design Specifications recommend the negative moment reinforcement (b2 reinforcement) be extended beyond the inflection point. Based upon satisfactory previous performance and judgment, the Iowa Department of Transportation (DOT) Office of Bridges and Structures (OBS) currently terminates b2 reinforcement at 1/8 of the span length. Although the Iowa DOT policy results in approximately 50% shorter b2 reinforcement than the AASHTO LRFD specifications, the Iowa DOT has not experienced any significant deck cracking over the intermediate supports. The primary objective of this project was to investigate the Iowa DOT OBS policy regarding the required amount of b2 reinforcement to provide the continuity over bridge decks. Other parameters, such as termination length, termination pattern, and effects of the secondary moments, were also studied. Live load tests were carried out on five bridges. The data were used to calibrate three-dimensional finite element models of two bridges. Parametric studies were conducted on the bridges with an uncracked deck, a cracked deck, and a cracked deck with a cracked pier diaphragm for live load and shrinkage load. The general conclusions were as follows: -- The parametric study results show that an increased area of the b2 reinforcement slightly reduces the strain over the pier, whereas an increased length and staggered reinforcement pattern slightly reduce the strains of the deck at 1/8 of the span length. -- Finite element modeling results suggest that the transverse field cracks over the pier and at 1/8 of the span length are mainly due to deck shrinkage. -- Bridges with larger skew angles have lower strains over the intermediate supports. -- Secondary moments affect the behavior in the negative moment region. The impact may be significant enough such that no tensile stresses in the deck may be experienced. 500 $a Catalogers note: This record is for the full-length report. A 4-page tech transfer summary is also available, at a link in this record. The summary is not cataloged individually. 516 $a Text file in PDF format. 536 $a Performed by Iowa State University, Institute for Transportation $c InTrans Project 13-469 536 $a Sponsored by the Iowa Department of Transportation, Iowa Highway Research Board $c IHRB Project TR-660 538 $a System requirements: Adobe Acrobat, Adobe Acrobat Reader, or other PDF reading software. 538 $a Mode of access: World Wide Web $u http://publications.iowa.gov/id/eprint/20465 650 0 $a Continuous bridges. 650 07 $a Bridge decks $2 trt 650 07 $a Bridge engineering $2 trt 650 07 $a Calibration $2 trt 650 07 $a Field tests $2 trt 650 07 $a Finite element method $2 trt 650 07 $a Instrumentation $2 trt 650 07 $a Moments (Mechanics) $2 trt 650 07 $a Parametric analysis $2 trt 650 07 $a Reinforcement (Engineering) $2 trt 650 07 $a Transverse cracking $2 trt 650 07 $a Bridge piers $2 trt 653 $a continuous deck 653 $a negative moment reinforcement 700 1 $a Jayathilaka, Sameera, $e author. $u Iowa State University. 700 1 $a Greimann, Lowell, $e author. $u Iowa State University. 710 2 $a Iowa State University. $b Institute for Transportation, $e performing body. 710 1 $a Iowa. $b Department of Transportation, $e sponsoring body. 710 1 $a Iowa. $b Highway Research Board, $e sponsoring body. 856 40 $a Iowa Publications Online $3 Full text access from Iowa Publications Online $z Full report $u http://publications.iowa.gov/id/eprint/20465 856 42 $a Iowa Publications Online $3 Full text access from Iowa Publications Online $z Tech transfer summary $u http://publications.iowa.gov/id/eprint/20465 856 40 $a Digital Repository @ Iowa State University $3 Full text access from Digital Repository @ Iowa State University $z Full report $u http://lib.dr.iastate.edu/intrans_reports/135 856 42 $a Digital Repository @ Iowa State University $3 Full text access from Digital Repository @ Iowa State University $z Tech transfer summary $u http://lib.dr.iastate.edu/intrans_techtransfer/84 941 $a 1 952 $l IAOX771 $d 20240710103125.0 956 $a http://locator.silo.lib.ia.us/search.cgi?index_0=id&term_0=F4B580F0B7CA11EC864CB83724ECA4DB 994 $a C0 $b UIGInitiate Another SILO Locator Search