Study On The Joint Mechanical Behavior Of Precast Bridge Piers With Grouted Sleeve Connection

With the advantages of less impact on traffic,high quality prefabricated members and short working period,the precast bridge construction technology has been widely implemented in China.Grouted sleeve connection is a state-of-the-art connection that is gradually becoming popular in our country recently,among which the connecting effect of the pier-cap beam joint or the pier-footing joint plays a key role in determining the mechanical behavior of the monolithic pier.Thus,it is significantly important to study the joint mechanical behavior of the precast pier with grouted sleeve connection to facilitate the implement of prefabricated pier construction technology and assess the reliability of such connection.Based on the first precast bridge adopting prefabricated pier constructed in Guangdong province,this paper designed and fabricated two cast-in-place models(group A)and four grouted sleeve connection models(group B and C)to research the mechanical behavior of the grouted sleeve connection joint used in the actual engineering.By conducting the pushover and cyclic loading experiments,this paper studied the failure mechanism and the seismic behavior of the joint of precast bridge with grouted sleeve connection.What’s more,numerical simulation analysis had been conducted to research the mechanical behavior of such joint by using Abaqus software.Depending on the results from the above experimental research and Abaqus analysis,some main conclusions were obtained below:(1)The joint of the precast bridge with grouted sleeve connections(B2 and C2)was founded to be flexual failure under the axial force and moment,meanwhile displaying a desirable ductility.Through the strain analysis on the longitudinal bars up and down the sleeves,it was found that the grouted sleeve connection was capable of translating force between the two connected bars effectively to ensure the integrity character of the precast bridge;(2)Employing sleeve could increased the stiffness of the concrete,so the cracking load of the group B model(called upper sleeve connection)simulating the actual engineering was 30% higher than the cast-in-place A2,meanwhile the cracks on the plastic hinge area were less and unevenly distributed.The seismic behavior of the B2 model was not as good as A2,and the calculated accumulative energy dissipation of B2 at the last displacement level was only 88.2% of A2;moreover,the displacement ductility of B2 was also lower than A2.(3)In group C model(called lower sleeve connection),in order to develop the fullness of the grout,this paper took methods to employ the sleeve in the footing,and grout the sleeve first,then assemble the prefabricated members of C model.Due to the developed bond property resulting from the grout used as bedding mortar,compared with the A mode,the peak load of model C was 13.6% higher than A2.From the results of the cyclic loading experiment,the accumulated energy dissipation of C2 was compared with A2,indicating that the lower sleeve connection joint was capable of advanced seismic behavior.However,accompanying with the flexual failure,brittle failure occurred in the interface of the joint,so that it was risky to using the connection type like C2.(4)This paper constructed finite element models for all specimens and analyzed the mechanical properties of the joints of the grouted sleeve connections by using Abaqus software.After that,the load-displacement curves,the stress of some parts and the damage state of concrete were obtained.The results showed that the numerical simulation is in good agreement with the experiment results.