Theoretical And Finite Element Analysis On Shear Capacity Of Bfrp-reinforced Recycled Aggregate Concrete Deep Beams Without Stirrups

Reinforced concrete(RC) structure has become the main structure form after more than one hundred years of development since it was invented. However, two problems of reinforced concrete structures are exposed at the same time. Firstly, many of concrete structures or components, such as bridges and pile caps in port reinforced with traditional steel rebar are subjected to corrosion constantly for poor environment conditions. Secondly, with the development of economy and society, human nowadays are facing with the serious situation such as stone material shortage, construction waste accumulation. As a result, looking for new material and technology to develop new types of structure becomes a research hotspot of scholars around the world.Basalt fiber reinforced polymer(BFRP) bar is a new engineering structural material with the properties of lightweight, high strength, antimagnetic, anti-static, non-corrosion. It can be used to replace steel rebar to reduce the structural damage caused by steel corrosion in RC member. Through Organic combining the BFRP bar and recycled concrete, this study explores the shear behavior of nine recycled concrete deep beams reinforced with BFRP bars without stirrups based on the theoretical and numerical simulation analysis.Based on Strut-and-tie model(STM), the calculation flow for shearing capacity predicting of the tested beams are proposed, and the prediction results are also compared with the results of American, Canadian, Japanese and Chinese standards. It can be concluded that, results according to Canadian standard CSA S806-12 are most stable, but a bit poor in fitting with the experimental results compared with STM. And the strut-and-tie model approach shows its well capacity to predict the shear strength of BFRP-reinforced recycled RC deep beam without stirrups as well with the ACI 440.1R-06. The approaches of JSCE-97 and GB 50010-2010 are conservative for predicting the shear strength of tested beams.The stress of recycled concrete and BFRP bars, cracking process, cracking load, shear strength and load-deflection curve are analyzed by reducing the elastic modulus of BFRP bars through numerical analysis by ANSYS. The shear span ratio, longitudinal reinforcement ratio, effective depth, and the strength of recycled concrete are defined as the variables.The results show that the cracking load of tested beams decrease with the increase of shear span ratio, and increase with the increasing of effective depth and compressive strength of recycled concrete, whereas, the effect of longitudinal reinforcement ratio is not obvious. The shear strength of the test beams decrease with the increasing of shear span ratio, but increase with the longitudinal reinforcement ratio, effective depth and the compressive strength of recycled concrete. The simulation method proposed in this paper can predict the shear strength of the test beam quit well. However, because the simulation analysis by ANSYS does not consider the bond-slip relationship between BFRP bar and recycled concrete, the deformation prediction of the test beams by ANSYS have certain deviations when compared with the experimental ones.