Effect of rebar self-stress on behavior of autoclaved aerated simply supported R/C thin beams subject to uniform transverse dead load

• Published in: Engineering structures Vol. 238; p. 112242
• Main Authors: Xu, Chunyi, Nehdi, Moncef L., Wu, Zanqing, Li, Jiaying
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.07.2021; Elsevier BV
• Subjects: Aeration; Arches; Autoclaved aerated; Beam; Bending; Concrete; Cracking moment; Dead loads; Deflection; High temperature; Mathematical models; Numerical model; Rebar; Reinforcing steels; Self-stress; Static loads; Steam curing; Steel; Steel bar; Stress; Beam; Self-stress; Numerical model; Steel bar; Bending; Concrete; Cracking moment; Autoclaved aerated
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2021.112242

•AAC beams incur counter-arch deflection with stored stress, inducing self-stress effect.•Cracking moment resisted by self-stress was 65.7% of theoretical cracking moment.•Effect of self-stress was confirmed experimentally and via numerical simulation.•Accounting for rebar self-stress captures load bearing capacity of AAC beams more accurately.•Considering rebar self-stress in design makes AAC beams a stronger contender in field applications. Autoclaved aerated concrete (AAC) beams typically incur counter-arch deflection with stored stress induced by the high-temperature and pressure steam curing. This study investigates the effects of the resulting self-stress on the flexural performance of steel rebar reinforced AAC beams. Accordingly, a simplified experimental model was designed to decouple the bar self-stress from other load mechanisms that exist in full-scale structures. Surcharge loading was applied, and the self-stress of steel rebar was measured by the releasing method. The cracking pattern of the AAC test beams and the associated load-deflection curves were analyzed. The values of self-stress in different locations of the beam were obtained, and the influence of steel bar self-stress on the cracking load was calculated. The test results show that the cracking moment resisted by the self-stress accounted for 65.7% of the theoretical cracking moment. Numerical simulation results confirmed that asymmetric reinforced AAC beams incur a counter-arch phenomenon, and further quantified the corresponding effect of self-stress on the cracking load. Therefore, accurately accounting for the rebar self-stress can more accurately define the cracking load capacity of AAC beams and should be considered in design, which should make AAC beams a stronger contender in diverse field applications.