I-type internal structures are commonly present in concrete hollow block masonry. A unified theory based on I-type internal structures is proposed to analyze types of masonry systematically. In this unified theory, the I-type element represents the I-type internal structure; the equivalent frame is introduced to analyze the interaction between the block and grout; and the characteristic strength of mortar is employed to measure the performance of mortar in masonry. Each subtheory of the unified theory is independent, and the application scope of this theory can be expanded by adjusting the subtheories. The predictions of the unified theory for the compressive behaviors of fully grouted, partially grouted, and ungrouted masonry are well matched with the measured data. Through targeted adjustments, the prediction of this theory for special cases is also accurate. The calculation results suggest that the unified theory can effectively analyze different types of masonry with an I-type internal structure.

An analytical tool called the stability model is proposed based on the experimental phenomena and reasonable assumptions. The predicting results verified the rationality of this method. Then, the block's softening process is discussed by comparing the stability and block softening models, and the concept of the block element overall softening is proposed. Next, the nominal deformation ratio, calculated by the method established in this study, is used to modify the block softening model. The modified block softening mode obtains accurate prediction results of compressive stress-strain curves and compressive strength, which shows the effectiveness of using the grouted masonry's nominal deformation ratio to describe the block element softening. Finally, the meaning of the nominal deformation ratio mu ' m and deformation ratio mu m is clarified. Moreover, the path of using these two pa-rameters to establish a unified theory for predicting the compressive behavior of grouted masonry is analyzed, and the scientific problems that need further study have been discussed.

This paper introduces an innovative internal configuration for the reinforced concrete masonry shear wall to improve seismic performance. A cyclic loading and monotonic loading test were carried out on reinforced concrete masonry shear walls with large cross-section core columns to study the in-plane response. The test walls’ crack patterns, deformation characteristics, and failure characteristics were similar to those of a slit shear wall, which indicated a dislocation between core columns. The cyclic loading test results showed that the test walls’ lateral bearing capacity was between 400 and 500 kN, the ultimate drift generally around 3%, and the equivalent viscous damping ratio with a non-linear response was found around 12%. Therefore, the test walls had ideal energy dissipation capacity as well as the lateral bearing capacity. According to the similarity phenomenon between the cyclic loading test and the monotonic loading test, three resistance mechanisms were proposed to explain the in-plane response of the wall, namely the core column-rotation mechanism, wall-rotation mechanism, and connector-shear mechanism. Based on the failure sequence of these resistance mechanisms, the intact wall was divided into two functional parts. One part was the masonry part, and the other part was the inner frame. The masonry part maintained integrity and required stiffness, and the inner frame dominated the in-plane response.

为了研究免模剪力墙的抗震性能,完成了1片免模保温剪力墙、1片免模非保温剪力墙和1片现浇剪力墙的拟静力试验,对比分析了试件的承载能力、滞回曲线、骨架曲线、刚度退化曲线、延性性能、耗能能力等抗震指标,并对免模剪力墙的整体性进行了分析.结果表明:免模剪力墙与现浇剪力墙的受力过程、破坏形态基本相同,抗震性能指标相近,具有与现浇剪力墙相近的抗震性能;与现浇剪力墙相比,免模剪力墙中预制模板和保温层的存在一定程度上削弱了墙体的工作性能,但是影响有限;在工作过程中,免模剪力墙预制模板平面内和平面外的相对位移均较小,没有出现较大范围预制模板与现浇区分离的现象,抗剪连接件和自然粗糙面的构造措施能够较好地保证免模剪力墙各组成部分的协同工作能力和墙体的整体性.

The I-type mechanical element is abstracted from the I-shaped substructures commonly existing in grouted masonry. According to the experimental results and comparison with literature, the rationality of the basic mechanical element is proved in this study. A constitutive law is proposed in this paper based on the concrete softened theory and the I-type mechanical element in order to predict the compressive stress-strain curve of grouted masonry. The prediction results of compressive strength, compressive stress-strain curve, and modulus of elasticity well match the test results available in the literature and the experimental results obtained from this study. It is asserted that the proposed constitutive law is able to provide reliable and accurate predictions. In the function of the proposed method, the deformation ratio of grouted masonry is used to describe the interaction process on blocks. Moreover, mathematical analysis shows that the value of this parameter has a significant impact on the prediction curve, which deserves further study.

本文通过8片免模剪力墙与1片现浇剪力墙低周反复加载试验,研究了免模墙体的抗震性能,比较了裂缝开展规律和破坏特征上与现浇墙体的异同.试验结果表明:除保温侧外,免模墙体裂缝开展与现浇墙体类似,破坏时预制模与核心现浇混凝土在塑性铰区域压溃程度有明显差别,保温墙体两侧预制模压溃程度也不一致;根据试验现象,建立了考虑不同加载阶段预制侧模参与工作程度的四折线骨架曲线特征点的计算方法,根据屈服后实测的各级滞回曲线滑移与捏拢等形状特征,建立了考虑刚度退化、强度退化及滑移的滞回规则.计算结果表明:计算特征点与实测特征点较为接近,模拟滞回曲线能很好的反映实测滞回曲线的规律.本文提出的恢复力模型作为免模剪力墙进行弹塑性动力分析的依据是合理的.

文章通过文献对比与试验验证,提出普遍存在于灌孔砌体内的工字受力单元,以混凝土受压软化理论为基础,推导出适用于具有该种受力单元的灌孔砌体受压应力-应变本构关系,表达式考虑了孔洞率、砌块与灌芯混凝土的强度比及软化系数的影响.计算结果表明:文中提出的公式对文献资料与试验实测的峰值点都给出了较为准确的预测,切线模量的退化较好地反映了与灌孔砌体受力破坏过程中的3个阶段,计算曲线与实测曲线契合程度较高.试验现象表明:以工字受力单元为基础构造的受压试件出现与文献资料记录类似裂缝开展规律和破坏特征,试验中观察到明显的三阶段破坏过程;工字受力单元具有较高的合理性,文中公式预测结果与文献资料及试验数据吻合良好,对具有相同内部结构的灌孔砌体有比较高的适用性.

In order to study the effect of varied axial compression ratios on the seismic performance and the cooperative performance of the non-template insulation shear wall,pseudo-static tests were carried out on 3 pieces of insulation shear wall with axial compression ratios of 0, 0.1 and 0.2.T he development and distribution of cracks in the prefabricated concrete template on both sides of the wall were observed and recorded,and the test data such as displacement ductility coefficients,hysteresis curves and skeleton curves of the specimens were obtained. Based on the analysis of the curves and destruction modes,the failure mechanism of the non-template insulation shear wall under low cyclic loading was obtained.The results show that the failure process can be divided into three phases:uncracked,with cracks in the work and fail.The cracks in all 3 specimens develop and distribute uniformly during tests,w hich show s good cooperative performance,and the concrete of corner all crush substantially when the wall is broken.With the increase of the axial compression ratio,the cracking load of prefabricated concrete template increases gradually,and the position of the horizontal crack is gradually shifted downwards,the ultimate bearing capacity and stiffness increase while the ductility decreases. The study provides necessary scientific basis for further investigation on the failure mode and seismic performance of non-template insulation shear wall.

采用蛇形钢筋研究叠合板拼缝的受力性能,并且与钢筋网片进行对比分析,综合评价蛇形钢筋的抗裂性能并判断是否能取代传统的钢筋网片;进行了叠合板带两点静力加载试验研究,通过此次试验形成了新型叠合板带拼缝抗裂系列试验;通过对比荷载-挠度曲线,分析了构件刚度变化过程和挠度发展过程,记录了裂缝出现和开展过程;分析了蛇形钢筋的受弯变形图,得出了蛇形钢筋在受弯变形后对混凝土产生的挤压力,并给出了构造措施的设计建议.结果表明:在配筋率降低的条件下,PK-S叠合板带整体刚度较强,荷载-挠度曲线屈服段较长,延性没有发生退化;裂缝发展缓慢,蛇形钢筋对裂缝开展有明显抑制作用,裂缝和对比组叠合板相差不多,甚至裂缝数量多于对比组叠合板,蛇形钢筋的抗裂效果优于钢筋网片;折角范围取为40°～60°,经过加工时最好在60°左右,可得出姿态良好的蛇形钢筋.

A kind of non-template insulation shear wall made of A,B side prefabricated concrete templates,cast-in-place concrete layer,insulation layer and shear connector was put forward. The prefabricated concrete template was manufactured in the factory and transported to the construction site as the cast-in-place concrete layer template.Through the pseudo-static test on 2 pieces of the non-template insulation shear walls,the feasibility of construction process was investigated.The integrity,cooperative performance of wall under the condition of different construction measures used in A side prefabricated concrete templates were studied.Meanwhile, the failure pattern, bearing capacity, hysteretic characteristics, skeleton curve, stiffness degradation,ductility and energy dissipation capacity of wall from loading to failure were also analyzed.The suggestions on the application of the shear wall in engineering were put forward. The results show that the construction of non-template insulation shear wall is simple and feasible.The shear wall has good integrity and similar seismic performance under the condition of two different construction measures used in A side prefabricated concrete templates.

Four full‐scale reinforced concrete frames ,including one bare frame without infilling walls and three infilled frames with the new cross hole hollow block masonry ,were tested to study the seismic performance under constant vertical force and horizontal low reversed cyclic loading .T he damage behavior ,hysteretic characteristics ,skeleton curve ,displacement ductility , stiffness degradation , strength degradation and energy‐dissipating capacity of frames with different types of connections were studied .The results show that the seismic performance of flexible connection specimen is between empty framework and rigid connection specimens ,and the seismic performance of the specimen whose frame beam and the infilled wall are connected by tie steel bars has been improved relative to unset specimen ,but the increase is limited .

Three specimens with different boxes ,a cast-in-place slab ,a visible-box slab and an invisible-box slab ,were designed to study the influence of box on mechanical behavior of concrete hollow-ribbed floor .The failure patterns ,load-strain curves of rebar and concrete as well as load-deflection curves at mid-span ,were obtained by static experiment . The cracking moment and ultimate moment of specimens were analyzed comparatively .The results show that the precast concrete box works well with cast-in-place ribs , stiffness of cast-in-place slab and assembled monolithic slab are about the same . The cracking moment and ultimate moment of visible-box slab and invisible-box slab are lower than those of cast-in-place slab , on account of feeble interface between cast-in-place ribs and precast concrete box ,as well as discrete rebars at the bottom of slab . The calculated values of cracking moment and ultimate moment are in good agreement with the test values .

Three full‐scale models of one‐story‐one‐bay reinforced concrete (RC ) frames were tested to mainly investigate the effects of concrete horizontal‐hole hollow blocks infilled wall on the seismic behavior of RC frames under low cyclic loading .The test failure modes ,hysteresis curves ,skeleton curves , stiffness degradation , energy dissipation capacity and other seismic performance indexes were compared and analyzed .The seismic behavior of concrete horizontal‐hole hollow blocks infilled wall‐RC frames was evaluated . The results show that concrete horizontal‐hole hollow blocks infilled wall‐RC frames meet the principle of strong frames and weak infilled wall ,and the final failure mode is close to that of space frame .The concrete horizontal‐hole hollow blocks filled wall has stiffness effect to RC frame ,and the horizontal bearing capacity and lateral stiffness of frame were improved greatly .The concrete horizontal‐hole hollow blocks infilled wall and frame structure are both involved in the hysteretic energy dissipation . The concrete horizontal‐hole hollow blocks infilled wall‐RC frame shows good seismic behavior .