Experimental Study On Bond-anchorage Of Glued Bamboo Glued-in Rods

Glued-in rods connection is a new type of joint,which has the advantages of high strength,high rigidity and good appearance.At the same time,because the rod is placed inside the component,it has certain fire and corrosion resistance.In this paper,the influence of edge distance,glue layer thickness,bolt diameter and planting depth on the failure mode,pull-out strength and deformation performance of glued bamboo glued-in single rod connection is studied through the pull-out test.And the influence of these geometric factors on the bond stress distribution is analyzed by pasting strain gauge inside the bolt.Then,on the basis of experimental research,the finite element model is established and the parametric analysis is carried out.Finally,based on the experiment and finite element analysis,the bond anchorage mechanism of glued bamboo glued-in rods is analyzed,and the bond slip model suitable for glued bamboo glued-in rods is proposed,and the calculation formula of the connection bearing capacity of glued bamboo glued-in rods is established by using the parameter method.In addition,based on the study of bond anchorage performance of glued bamboo glued-in single rod,the influence of spacing and slenderness ratio of rods on the failure mode,ultimate load and deformation performance of glued bamboo glued-in multi rods connection is studied.The main conclusions of this paper are as follows:(1)There are three typical failure modes of glued bamboo glued-in single rod connection:splitting failure of glued bamboo,pull-out failure of bolt and yield failure of bolt;in order to avoid splitting failure of glued bamboo,it is recommended that the edge distance be greater than or equal to 5d;the thickness of glue layer has little impact on bearing capacity,considering the economy and better guarantee of uniform thickness of glue layer,it is recommended that the thickness of glue layer be 2mm;when the bolt specification is M12,if When slenderness ratio is less than 10,the failure mode is bolt pull-out failure.If slenderness ratio is greater than or equal to 10,the failure mode is bolt yield failure.When the bolt size is M16,if the slenderness ratio is less than or equal to 10,the failure mode is bolt pull-out failure,if the slenderness ratio is greater than or equal to 15,the failure mode is bolt yield failure.(2)In general,the distribution of bond stress is large at both ends and small in the middle.The peak value appears near the loading end,and with the increase of load,the peak value transfers to the direction of anchorage end.In this paper,it is not found that the edge distance has a significant impact on the distribution of bond stress.With the increase of the thickness of adhesive layer from 1mm to 3mm,the distribution of bond stress of will be more uniform.In the case of the same slenderness ratio,when the bolt diameter increases from 12 mm to 16 mm,there is no obvious difference in the distribution of bond stress;in the case of the same bolt diameter,the bond stress distribution of the short anchor specimens are more uniform,while the long anchor specimens have obvious stress concentration near the loading end.(3)The results of numerical simulation are in good agreement with the experimental results.(4)Based on the parameter method,the ultimate load calculation formula of glued bamboo glued-in rods connection can better predict the bearing capacity of the joint.(5)It is suggested to take 4d as the spacing of rods,and the ultimate load of glued bamboo glued-in multi rods should be multiplied by the reduction factor of 0.95 based on the sum of the ultimate load of corresponding single rod.