Analysis On Overlapping Performance Of Welding Reinforced Anchorage Connection By Grouting In Preformed Hole

In recent years,in order to meet the needs of economic development and environmental protection,prefabricated concrete structures have been developed rapidly at home.In the process of the development of prefabricated concrete structure,the connection technology of prefabricated components is the key problem.At present,more connection technology is used in the engineering as the sleeve grouting anchor connection.At the same time,the reinforced anchorage connection,as a convenient and inexpensive connection technology,is being developed by many scholars and gradually applied in practical engineering.Based on the existing reinforced anchorage connections,a new type of anchorage connection technologies developed,which is welding reinforced anchorage connection by grouting in preformed hole.In this paper,the construction method of this connection is introduced,and the theoretical research is carried out on the anchoring performance and lap length of the connection.Because the two longitudinal bars of the lap joint are anchored in the grouting and the concrete,the anchoring performance of the grout metal bellows is analyzed firstly.In this paper,the anchoring performance can be analyzed by being divided into three bonding surface:(?)concrete-metal bellows interface,(?)metal bellows-grout interface and(?)grout-rebar interface.Interface ? and ? are analyzed by adopting the method of reinforced concrete anchorage performance.And interface ? is equivalent to interface of concrete-filled steel tube.The bonding strength and anchorage length of the three interfaces were obtained and compared.And the conclusion is that the anchorage bonding strength of the reinforced anchorage is higher than the anchorage bonding strength of reinforced concrete.According to the analysis of the anchorage performance of the grouting metal bellows,the failure forms of welding reinforced anchorage connection by grouting in preformed hole are concrete splitting failure and embedded pull-out failure.Splitting failure is analyzed in theory research by adopting the thick wall cylinder calculation model with concrete cracking stage of elastic,while considering effect of stirrup.And split-failure bonding strength calculation formula are obtained.Then,based on the existing research conclusions,the bonding strength of the pull-out failure is obtained,and the minimum stirrup reinforcement ratio of pull-out failure is given.Finally,considering the distribution of bonding stress,theformula for calculating the limit lap length of splitting failure and pull-out failure is obtained.In order to apply to engineering,the reliability analysis of the reinforced anchorage connection is carried out on the basis of the above research conclusions.The limit lap length of the reliability assurance of different concrete strength grades is obtained by using approximate method.In the end,the paper gives the design suggestion of lap length and stirrup reinforcement ratio of the welding reinforced anchorage connection by grouting in preformed hole in the engineering..