TY  - BOOK
AU  - Gonzales, Winifredo Encinares.
AU  - 
ED  - 
ED  - 
ED  - 
ED  - 
SN  - 2
PY  - 0000///46
CY  - 
PB  - 
KW  - 
KW  - 2
KW  - 0
KW  - 6
KW  - 20
N1  - Thesis (M.A.) -- Pamantasan ng Lungsod ng Maynila, 2009.;A directed study presented to the faculty of Graduate School of Engineering in partial fulfillment of the requirements for the degree Master of Engineering (MEng) with specialization in Structural Engineering; 5
N2  - ABSTRACT:  The manufacturing of high strength concrete-reinforcing bars in the Philippines that employs a new method in quenching and tempering of steel bars known as TEMPCORE technology, that significantly increased the tensile strength of bars at relatively low cost, has created various concerns regarding the efficiency of the bars.  This study was performed to determine the effect of bending on the TEMPCORE bars (weldable deformed bars of Grade 415) in accordance with standard hook bend of the Philippine National Standards (PNS) and the National Structural Code of the Philippines (NSCP) which is six (6) times the bar diameters. Furthermore, the bars were subjected into bending within four (4) times the bar diameters which is more critical than bending requirements as provided by PNS and NSCP. Also, the research study was aimed to determine the capacity of a straightened TEMPCORE bar that was previously bended at 180 degree shape, which were frequently performed in the actual construction operations at various instances such as incorrect fabrication, accidental bending and space or clearances requirements during construction and many any other similar conditions in straightening of steel bars.  The results of the experiment show that the bended specimens bars was capable of bending without the manifestation of cracks on both inner and outer surfaces of the bars within the bending diameters as required by PNS and NSCP under the standard hook bend. Also, the specimens has no manifestation of visible cracks after bended at four times (4) the bar diameter or bending in excess of the code requirement even without manifestation of visible cracks should be avoided due to the increased residual stresses within the inner and outer surface of the bar that will reduce capacity of the bars to carry additional load. Finally, straightening of bars after being bended is not recommended and should not be permitted in the field operation of rebars especially in critical section of structural members where plastic hinges occur and most especially for structures situated in earthquake regions
ER  -