【作者】 刘阳；

【导师】 李新平； 郑小红；

【作者基本信息】 华南理工大学 ， 土木工程， 2020， 硕士

【摘要】 装配式桥梁建造技术由于具有对地面交通影响小、预制构件质量高、工期短等优势,近年来在我国城市桥梁快速建设中得到大力推广。灌浆套筒连接节点是近几年我国装配式桥墩节点主要采用的一种新型连接方式,其中墩柱与盖梁、承台之间上、下节点的连接效果是保证装配式桥墩整体受力的关键。因此,对灌浆套筒连接节点力学性能的研究对于装配式桥墩技术的推广应用和节点连接的可靠性评估具有重要的意义。本论文以广东省第一座装配式桥墩为工程背景,以其灌浆套筒连接节点为研究对象,按照1:4的缩尺比例,制作了2个整体现浇对比试件(A组),4个灌浆套筒连接装配式试件(B组、C组),通过模型试验的方法,分别进行了水平单向加载试验、拟静力反复加载试验,对灌浆套筒连接装配式桥墩节点的破坏机理和抗震性能进行了试验研究。另一方面,运用Abaqus有限元分析软件对灌浆套筒连接节点的受力性能进行了数值模拟分析。通过以上实验研究和有限元分析,主要得到以下结论:(1)灌浆套筒连接装配式桥墩节点在压弯荷载作用下,主要发生墩柱-承台节点处的弯曲破坏,具有一定的延性。对钢筋的受力分析表明,套筒连接的上、下钢筋均能达到屈服,说明采用灌浆套筒连接可以进行力的有效传递,保证了装配式桥墩的整体受力;(2)采用与依托工程相同的灌浆套筒连接技术的B组(简称上套筒连接方法),由于套筒增加了柱脚部分的刚度,开裂荷载比现浇试件提高了约30%,试件根部裂缝较少,分布不均匀;屈服荷载和峰值荷载与现浇试件接近;抗震性能与现浇试件相比有所下降,B2的累计耗能为A2的88.2%;正、负向位移延性系数均小于A2。(3)C组(简称下套筒连接方法)中,为了提高套筒的灌浆饱满度,将套筒预埋在承台内,先往套筒内注满灌浆料再进行拼接。由于灌浆料增强了墩柱与承台连接界面的粘结性能,与现浇试件相比,峰值荷载增加了13.6%;拟静力试验结果表明,C组滞回曲线的耗能比现浇节点试件的要大,表明下套筒连接节点的抗震性能有所增加;但试件发生弯曲破坏的同时,也发生了界面粘结的脆性破坏,工程应用上有一定的风险。(4)通过ABAQUS软件,建立了缩尺试件的有限元模型,对灌浆套筒连接的节点受力性能进行分析,获得了荷载-位移曲线、混凝土的损伤分布和各部件的应力状态。结果表明数值模拟与试验结果吻合较好。更多还原

【Abstract】 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.更多还原