Analysis Of Anchor Group Behavior Of Concrete

On the basis of summarizing the correlative research achievements about post-installed chemically bonded rebar, this paper discusses the anchor group effect in adhesive anchors through experimental study and analytical research. The main contributions are below:In the first part, background and correlative achievement about this research are introduced.In the second part, pull-out experimental researches on post-installed chemically bonded group rebar in concrete are introduced. In the experimental researches, 36 group adhesive anchor members are discussed, which using JGN structural adhesive, in 6d, 9d, 12d and 15d embedded depth; 14mm, 16mm and 18mm rebar diameter; 3d, 5d and 8d anchor space respectively. It studies the failure models, P-s curves, capability, stiffness and ductility of the members, and discusses the effects of various diameter anchors and various depths and various spacing on the anchorage performance. Base on the experiments, equations of the anchor groups are recommended, and the calculated results are shown to be in close agreement with the test value.In the third part, analyzes adhesive anchor group behavior using finite element method in macroscopical elements. It discusses the effect of different concrete crack model to the analyzing results, and the rotating angle crack model is used to increase precision of results. Also, discusses the influence of the shear transfer coefficients for an open crackβt, the shear transfer coefficients for a closed crackβc and the maximal crack strainεmax to the analyzing results. And all of the model parameters are confirmed by a great deal of calculation, the computed results are close agreement with the test results.In the fourth part, based on research achievements about bond-anchorage of rebar and concrete, the analytical method and the numerical calculation on bond-anchorage of postinstalled chemically rebar are discussed.Through combining experimental research and theory analysis, this paper discusses all-around problems on anchor group effect in adhesive anchors, and offers some suggests on engineering practice.In addition, it studies the method using small diameter core samples to confirm concrete intension. Based on examination, the conversion standard between small diameter core samples and standard diameter core samples is framed, which offers warrant for using small diameter core samples to confirm concrete intension.