【作者】 吴静；

【导师】 胡曙光； 王发洲；

【作者基本信息】 武汉理工大学 ， 建筑材料与工程， 2010， 博士

【摘要】 地震是人类面临的严重自然灾害之一。我国属地震多发国家,需要考虑抗震设防的地域分布广,研究建筑结构的抗震性能十分必要与迫切。地震力与结构的自重有关,降低静载重可以减小建筑物在地震时的惯性力,从而降低建筑物的地震反应。轻集料混凝土具有自重轻、轴压强度高、与钢筋的弹性阶段协同工作能力强、抗裂性能和抗震性能好的优点,若将其用于抗震结构无疑具有极大的潜力。但由于轻集料混凝土的强度通常较低,弹性模量较小,脆性问题突出,直接将其用于钢筋混凝土柱还存在强度、刚度和延性难以满足重要建筑结构要求的技术问题。据此,本文对由普通优质集料取代部分轻集料制备而成的高强轻质混凝土(HSLC)的性能进行了研究,建立了高强轻质混凝土的本构关系,探明了混凝土材料与钢筋的配合关系,探讨了高强轻质混凝土与钢筋的匹配设计原理,提出了采用多重螺旋箍筋形式对高强轻质混凝土进行增韧的抗震设计方法,通过理论分析和力学计算得到了多重螺旋箍筋柱正截面承载力计算公式,对高强轻质混凝土-多重螺旋箍筋柱抗震性能和经济性进行了综合分析。论文开展的主要工作和取得的重要成果有：制备了强度等级为C60高强混凝土(HSC)、高强轻集料混凝土(HSLAC)和HSLC,获得了HSC、HSLAC和HSLC的单轴受压应力-应变全曲线,分析了三种混凝土材料的裂缝扩展模式和在单轴荷载作用下的变形特性及破坏形态。对高强轻质混凝土应力-应变全曲线进行数据拟合,得到其应力-应变全曲线数学方程式,为高强轻质混凝土结构设计与有限元分析提供了参考依据。基于抗震性能的要求,研究了混凝土材料与钢筋的配合关系,对普通箍筋约束HSLC、HSC和HSLAC受压构件进行了低周反复荷载试验,对比研究了相同箍筋约束条件下,HSLC、HSC和HSLAC三种混凝土框架柱的破坏形态、滞回特性、延性、耗能能力和刚度退化等抗震性能。结果表明,用普通优质集料取代部分轻集料可以提高轻集料混凝土的抗震性能,HSLC不仅可以降低结构自重,减小地震破坏力,还可以满足重要结构对混凝土承载力、刚度和延性的要求。通过体积配箍率对钢筋HSLC柱抗震性能影响规律的研究,探明了混凝土材料与钢筋的配合关系,探讨了HSLC与钢筋的匹配设计原理。依据HSLC的物理力学性能及其与钢筋的配合关系,鉴于圆形螺旋箍筋优异的约束效应,提出了利用多重螺旋箍筋对HSLC进行增韧的抗震设计思路和设计方法,设计制作了单螺旋、4-螺旋和5-螺旋箍筋约束HSLC框架柱试件；针对现有关于约束混凝土理论模型用于分析多重螺旋箍筋柱存在的问题,从单个螺旋箍筋柱力学理论出发,分析了多重螺旋箍筋混凝土柱的正截面承载能力,提出了多重螺旋箍筋混凝土柱正截面强度计算公式,该公式为多重螺旋箍筋柱的设计及研究提供了理论及计算依据。系统研究了单螺旋、4-螺旋和5-螺旋箍筋形式下,钢筋HSLC柱的破坏特征、滞回特性、延性、耗能能力和刚度退化等抗震性能,重点研究了轴压比和配筋率对5-螺旋箍筋柱的影响作用,并对高强轻质混凝土-多重螺旋箍筋柱抗震性能和经济性进行了综合分析。结果表明,5-螺旋箍筋技术可以大幅度提高钢筋HSLC框架柱的延性和耗能能力；在相同抗震设防等级下,多重螺旋箍筋增韧高强轻质混凝土比普通钢筋混凝土降低自重近20%,减少用钢量高达15%以上,大大降低了构件抗震设防成本。更多还原

【Abstract】 Earthquake is one of the most serious natural disasters faced by human being. China is an earthquake-prone country with great losses caused by earthquakes, so it is quite necessary and urgent to study the seismic performance of structures and bridge. Seismic force is related to the weight of structure, which can be decreased by reducing the building dead-load. Lightweight aggregate concrete (LAC) has great potential applications in seismic structure for its advantages of low density, high specific strength, crack resistance, earthquake-proof, and high cooperation deformation capability with reinforcement during elastic stage. However, LAC can’t be used directly into reinforced concrete column due to its disadvantages of low compressive strength, low modulus and high brittleness. In this thesis, based on the research of interface strengthening technology, the high strength lightweight concrete (HSLC) was prepared, and which was confined by multi-spiral stirrups. The multi-spiral confined HSLC column has good ductility and seismic performance. The multi-spiral stirrups with less steel consumption greatly reduce the cost of earthquake resistance protection of compression member.The main results obtained in this study are as follows:Main factors influencing the mechanic properties of HSLC were found out. Key technique of interface strengthening for preparing HSLC was grasped. The proportion parameters of HSLC, high strength concrete (HSC) and high strength. lightweight concrete (HSLAC) with the same strength of C60 were confirmed. The stress-strain curves of HSLC, HSC and HSLAC were obtained by tests; the deformation properties, failure model and damage mechanism were also discussed. Formula of constitutive relations model of HSLC was revised, which established the theoretic foundation for structural design and finite element analysis.In order to study the match relationship between concrete and stirrups, failure patterns, "P-△" hysteretic curves, skeleton curves, ductile coefficients, energy dissipation and strength degeneration of steel reinforced HSLC, HSC and HSLAC columns were studied by low cyclic reversed loading test. Results indicate that HSLC can reduce the weight of structures, so as to decrease the earthquake destructive force; it can also meet the need of important building on load capacity, ductility and stiffness.The toughening seismic design idea of multi-spiral stirrups for confined HSLC was proposed, and 8 multi-spiral confined HSLC column specimens were prepared for the low cyclic reversed loading test. Based on the three-direction stress law of confined concrete, the load carrying capacity of the rectangular cross section concrete column with multi-spiral is analyzed, and the calculated equation of the load carrying capacity is proposed, which provides a theory and calculation basis for multi-spiral confined concrete column design and research.The seismic performances of single spiral,4-spiral and 5-spiral HSLC columns were studied, including failure patterns, hysteretic curves, skeleton curves, ductile coefficients, energy dissipation and strength degeneration. The influences of axial compression ratio and reinforcement ratio on the seismic properties of 5-spiral confined HSLC columns were discussed. It is verified through experiments that multi-spiral confined concrete columns have better mechanical properties than single spiral columns and the multi-spiral significantly increase the column’s strength, plasticity, ductility and anti-seismic capability. Under the same seismic fortification level, the multi-spiral stirrup reduces the steel consumption by more than 15%.更多还原