Experimental And Theoretical Study On Seismic Behavior Of Steel Reinforced Recycled Concrete Frame Infilled With Recycled Concrete Blocks

Steel reinforced recycled aggregate concrete structure is the combination of steelreinforced concrete structure and recycled aggregate concrete structure. It not only hashigher bearing capacity and better seismic performance, but also can save energy andprotect environment, which complies with the state’s environment protection policy. Inthe structure of infilled frame, the part of infilling wall bears a considerable portion ofthe seismic effect actually. The new masonry materials are taking the place of thetraditional solid bricks, including recycled aggregate concrete hollow bricks, fly-ashbricks and aerated concrete blocks. The basic mechanical performance of steelreinforced recycled aggregate concrete beam and column has been studied. And thecurrent studies of new masonry materials mainly focus on material property such aslightweight and heat preservation. No research has been done on the seismic behaviorof steel reinforced recycled aggregate concrete frame infilled with new masonrymaterials. Based on the previous studies, the main contents of this dissertation arepresented as follows.According to the experimental study on7models of one-bay and one-story framecomposed of recycled aggregate concrete beams and steel reinforced recycledaggregate concrete columns under low cyclic reversed loading, the infilling wallconfigurations, masonry strength grade, lacing rebar spacing, axial compression ratioand width-height ratio of infilling wall were considered as design parameters, thefailure process and pattern were observed. The strain distribution of shaped steel andrebar on key position, load-displacement hysteretic loops and skeleton curves were obtained. The mechanical performance such as load bearing capacity, displacementductility, inter-story drift ratio, energy dissipation, strength deterioration and stiffnessdegradation were studied. And the influence of design parameters on structural seismicbehavior was analyzed.According to the P-Δ hysteresis curves and skeleton curves of frames with differentinfilling wall configurations, the restoring force models which are suitable for theframe with corresponding infilling wall configurations were established in this paper.The models used the four or three line of stiffness degradation model which include theskeleton curve model, unloading stiffness degradation and hysteresis rules. Bytheoretical analysis and test data regression, the calculation method of initial stiffnessof frames with different infilling wall configurations was established. The experimentalresults agree well with calculated results, which verified the rationality of the restoringforce models.The static elasto-plastic analysis on steel reinforced recycled aggregate concreteframe with and without infilling wall under monotonic loading was carried out by usingfinite element software ABAQUS. The ABAQUS calculated results agreed well withexperimental results, verified the correctness of the finite element model. According tothe calculated results, the mechanical performance of the structure were analyzed;obtaining the pattern of stress distribution of concrete, shape steel, and infilling wall ateach key position, and the deformation of structure was also studied. Furthermore,parametric study of load-displacement curves of the structure were carried out based onthe previous theoretical analysis. The concrete strength, steel strength, axialcompression ratio, masonry strength and width-height ratio of infilling wall were allconsidered as analysis parameters, influential regulation of every parameter to thestructure was observed. In addition, finite element software PERFORM-3D was usedto analyze the cooperative work performance and the shear force distribution of framepart and infilling wall part of the whole structure.Based on the current code and the research results at home and abroad, the currentresearch status and partition principles of structural performance level were summarized.The seismic performance level of steel reinforced recycled aggregate concrete columns,recycled aggregate concrete beams and infilling walls were partitioned. Drift was used as the measurement index to quantify the seismic performance of steel reinforcedrecycled aggregate concrete frame infilled with recycled aggregate concrete hollowblocks. Meanwhile, the performance status of structural members was measuredaccording to the partitioned structural performance level, indicating that the partition ofstructural performance level can sufficiently protect the performance level of eachstructural member. By comparing the performance level put forward in this dissertationwith the structural deformation value in “partition criterion of building earthquakedamage level”, every performance level higher than or equal to the code value, whichshow that the reasonability of the structural performance level put forward in thisdissertation.Based on PERFORM-3D and the capacity spectrum method, pushover analysis on6frame models with different infilling wall configurations were conducted. Thestructural inter-story drift ratio and the distribution clouds of structural memberperformance level were observed. By statistical analysis of the inter-story drift ratio andmember performance level, the structural seismic performance of the6models underdifferent design seismic action was evaluated.