2002 Fiscal Year Final Research Report Summary
Flexural and Shear Properties of Prestressed Continuous Beams with Lightweight Concrete
Project/Area Number 
13650514

Research Category 
GrantinAid for Scientific Research (C)

Allocation Type  Singleyear Grants 
Section  一般 
Research Field 
土木材料・力学一般

Research Institution  Osaka Institute of Technology 
Principal Investigator 
KOBAYASHI Kazuo Osaka Institute of Technology, Eng., Professor, 工学部, 教授 (10021586)

Project Period (FY) 
2001 – 2002

Keywords  PC continuous beams / Lightweight concrete / Normalweight concrete / Flexural properties / Shear properties / Nonlinear analysis 
Research Abstract 
Flexural and shear behavior of twospan continuous prestressed concrete (PC) beams using high performance lightweight concrete was studied in comparison with that of normalweight concrete beams. Conclusions obtained from this study are summarized as follows. Regarding flexural properties, (1) rigidity of lightweight concrete beam (L beam) was lower than that of normalweight concrete beam (N beam), (2) no significant difference was found between L and N beams as to moment redistribution up to the ultimate state after flexural cracking, (3) ultimate flexural strength of L beam was almost equal to that of N beam with comparable concrete compressive strength, and those could be calculated well by the limit analysis. (4) flexural behavior of L and N beams up to the ultimate state could be estimated well by a nonlinear analysis adopted here. Regarding shear properties which were examined as to prestressed reinforces concrete (PRC) beams in this study, (1) shear strength (V_c) carried by concrete of L beam was lower by about 25% on the average than that of comparable N beam, (2) V_c of L beams could be calculated well by considering together with effect of prestress and strength reduction factor for shear, (3) measured stirrup strains after shear cracking of L beam were close to calculations obtained by setting all of safety factors in the JSCE Code equation to be specified values, while those in N beams were close to ones based on safety factors of 1.0, (4) shear behavior of both L and N beams could be estimated well by applying modified compression field theory, (5) flexural crack width of both L and N beams could be calculated well using steel stress based on nonlinear analysis and JSCE Code equation for crack width.
