【作者】 刘国庆；

【导师】 谷倩；

【作者基本信息】 武汉理工大学 ， 土木工程， 2024， 硕士

【摘要】 为顺应国家倡导的传统建筑业转型与升级,装配式建筑结构以其绿色化、效率高、经济效益好等特点得到了全面发展。其中,装配式框架结构作为工程应用面最广泛的结构类型之一,成为专家学者的重点关注对象。然而,现有的装配式连接节点常有着核心区施工不便、装配精度要求高等未解决的技术问题,为此本文提出了一种装配式混凝土U形梁-核心区一体化预制柱连接节点,并对其开展了抗震性能试验研究和有限元分析,论文主要研究内容和结论如下:(1)基于对常见装配式梁柱节点中湿式连接和干式连接的的优势的总结和当今工程实际需求,提出了一种钢筋传力可靠、施工简便的装配式混凝土U形梁-节点核心区一体化预制柱连接节点。随后以某车辆段综合楼为设计原型,设计了3个足尺预制节点试件和1个现浇对比试件,并对节点构造的设计原则进行深入分析,对节点的加工制作、装配方式等施工工艺进行详尽阐述。(2)对3个足尺预制节点试件和1个现浇对比试件开展低周反复荷载试验,观察各试件的破坏过程与最终破坏形态,发现现浇节点表现为牛腿边缘上方混凝土压溃的“梁铰机制”破坏模式,而预制节点为非等同现浇破坏,主要表现为梁柱脱离且梁端混凝土压碎的延性破坏模式,混凝土损伤程度小于现浇试件。(3)通过对拟静力试验数据中滞回曲线、骨架曲线等深入对比分析,得出以下结论:预制节点的正向峰值承载力仅低于现浇节点5.6%,但负向峰值承载力降低24.3%;预制节点正向强度退化系数更高,具有优于现浇节点的强度安全储备;两类节点均属于延性连接,但预制式节点负向延性系数较现浇节点提升约一倍。另外,增加附加连接钢筋搭接长度对梁柱节点的负向峰值承载力和累积滞回耗能分别提升8.6%和58.1%,但对正向承载力没有显著影响。(4)采用ABAQUS有限元计算软件,基于混凝土塑性损伤模型和PQ-Fiber钢筋本构模型建立了装配式梁柱连接节点数值模型,将计算结果与试验结果对比分析验证数值模型可靠性。随后以该数值模型为基础,开展有限元参数拓展分析,结果表明当附加连接钢筋能与核心区灌浆料有效粘结时,装配式节点负向承载能力将显著提升,而增大附加连接钢筋直径和提高后浇混凝土强度等级对装配式梁柱连接节点的承载能力影响较小。更多还原

【Abstract】 In order to comply with the transformation and upgrading of the traditional construction industry advocated by our country,prefabricated building structures have been comprehensively developed due to their eco-friendliness,high efficiency,and economic benefits.Among them,prefabricated frame structures,as one of the most widely used structural types in engineering applications,have become a focal point of attention for experts and scholars.However,existing precast joints often face unresolved technical issues,such as inconvenient processing in the core area and high precision requirements in assembly precision.To address this,this thesis proposes a new type of prefabricated concrete U-shaped beam-to-column joint with integrated core area in precast column and conducts seismic performance tests and finite element analysis on it.The main research contents and conclusions are as follows:(1)Based on the summarization of the advantages of wet and dry connections in common prefabricated beam-to-column joints and the current engineering practical needs,a new type of prefabricated concrete U-shaped beam-to-column joint with integrated core area in precast column with reliable force transmission of reinforcements and simplified construction is proposed.Following this,using a comprehensive building in a vehicle section as the design prototype,three full-scale precast joint specimens and one cast-in-place comparison joint specimen were designed,and an in-depth analysis of the design principles of the joint construction,as well as a detailed description of the processing,fabrication,and assembly methods of the joints,was conducted.(2)Low reversed cyclic loading test was conducted on three full-scale precast joint specimens and one cast-in-place comparison joint specimen to observe the failure process and final failure modes of each specimen.The results show that the cast-in-place joint exhibited a“beam hinge mechanism”failure mode characterized by concrete crushing above the edge of the corbel,whereas the prefabricated joints have a nonemulative failure,which primarily showed a ductile failure mode characterized by the disconnection of the beam from the column and crushing of the concrete at the beam end,with less concrete damage than that of the cast-in-place specimen.(3)Through in-depth comparative analysis of hysteresis curves,skeleton curves,and other data from quasi-static tests,the following conclusions were drawn:the positive peak load bearing capacity of precast joints is only 5.6%lower than that of cast-in-place joints,but the reduction in negative peak load bearing capacity is 24.3%;the positive strength degradation coefficient of precast joints is higher,indicating a superior strength reserve compared to cast-in-place joints.Both types of joints are considered to be ductile connections,yet the negative ductility coefficient of precast joints is about double that of cast-in-place joints.Additionally,increasing the lap length of additional reinforcement results in an 8.6%increase in negative peak load bearing capacity and a 58.1%increase in cumulative hysteretic energy dissipation,but has no significant effect on positive load bearing capacity.(4)Using ABAQUS finite element analysis software,a numerical model of prefabricated beam-to-column joints was established based on the concrete plastic damage model and the PQ-Fiber reinforcement constitutive model.The reliability of the numerical model was verified through comparative analysis between computational results and experimental outcomes.Subsequently,based on this numerical model,finite element parametric studies were conducted.The results indicate that when the additional reinforcement has sufficient bonding property with the grout in the core area,the negative load bearing capacity of the prefabricated joints is significantly enhanced.However,increasing the section diameter of additional reinforcement and enhancing the strength grade of post-poured concrete have a minimal impact on the load bearing capacity of prefabricated beam-to-column joint.更多还原