【作者】 徐梅芳；

【导师】 尚守平；

【作者基本信息】 湖南大学 ， 结构工程， 2011， 硕士

【摘要】 混凝土小型空心砌块具有节土、节能的优势,是一种颇具竞争力和发展前景的新型墙体材料,自20世纪60年代起在我国得到广泛应用。但混凝土空心砌块墙体脆性较大,抗震性能差,而近年来发生的历次地震尤其是2010年在玉树发生的7.1级地震中,大规模混凝土空心砌块结构在地震中遭受破坏,究其原因,玉树县大量房屋所采用的空心砌块质量较差,没有良好的抗震构造措施,施工质量差,承载能力得不到保证。因此,研究经济有效的混凝土小型空心砌块加固方法具有重要的实用价值。高性能复合砂浆钢筋网(HPFL)是一种新型无机材料,以其加固效果显著和耐久、耐老化、耐火、施工便捷、环保等优点,受到国内外加固行业的青睐,应用日趋广泛。本课题组已对使用HPFL加固混凝土和砖砌体结构做了大量理论分析和试验研究,成果表明该加固法能有效提高构件的承载力、刚度、抗裂性和延性,且较碳纤维、钢板等加固法显得更为经济。本文首先通过对18个标准试件进行抗压强度试验,对比分析未加固试件和采用HPFL加固试件的最终破坏形态、应力—应变曲线、抗压承载力提高幅度。试验表明,该加固法对混凝土空心砌块墙体抗压强度的提高十分有效,且加固后墙体的裂缝数量增加,极限压应变得到提高。同时综合试验结果和理论研究分析,提出了HPFL加固混凝土小型空心砌块砌体抗压强度的计算公式。接着,我们通过对6片高宽比为0.78且采用不同加固方式的混凝土小型空心砌块墙体的试验研究,对比分析各墙体的破坏特征、承载力、滞回曲线、骨架曲线、刚度及刚度退化曲线、延性等。试验结果表明,加固后墙体的极限承载力得到提高,墙体的延性得到改善,尤其是采用圈梁构造柱加固方式后的墙体,开裂荷载也大大提高,破坏时裂缝发展充分,滞回曲线饱满,大大提高了墙体的耗能能力。另外,本文在试验的基础上,结合以往的砌体抗剪强度理论,并通过试验结果和理论研究分析,提出了HPFL加固混凝土小型空心砌块砌体抗剪承载力的计算公式。公式计算结果与试验结果能够较好地吻合,可供实际工程设计参考。更多还原

【Abstract】 The concrete small hollow block is a competitive and prospects of the development of new wall materials for the advantage of saving soil and section, and it is widely applied in our country since the1960s. However,the concrete hollow brick walls have larger brittleness and poor seismic performance .In recent years the several earthquakes especially the 7.1 magnitude quake that happened in Yushu in 2010,plenty of concrete hollow brick structures were damaged in the earthquake.It is investigated that many houses in Yushu were built with poor- quality hollow blocks and construction, and mainly they had no good anti-seismic measures and lacked the bearing capacity. Therefore,to find a economic and effective strengthening method for concrete small hollow blocks have important practical value.High Performance Ferrocement Laminate (HPFL) is a new type of inorganic material, which is gradually the favour of reinforcement industry and used widely because of its remarkable reinforcement effect,durability,ageing resistance,fire resistance performance,convenient construction and environmental protection.Our task group have done some research on concrete structure reinforced with HPFL,from which we drew a conclusion that the ultimate bearing capacity, stiffness,crack-resistance and ductility could be significantly promoted when reinforced with HPFL,and it would be more economical than other strengthening methods like using carbon fiber and steel plate.This paper firstly makes comparative analysis on the failure pattern, stress-strain curve and the ultimate compressive capacity of the reinforced specimens and the ordinary ones on the basis of 18 standard test pieces .The experiments showed that this method is very effective,with the number of the reinforced walls’cracks increasing and ultimate compressive strain improved. Based on the experiment and theory of masonry’s compressive strength, the formulas of the reinforced concrete small hollow concrete-block masonry compressive strength is presented.Then, the comparative analysis of failure modes, shear capacity, hysteresis curve, skeleton curve, stiffness and stiffness degradation curve, ductility are made by carrying out the low cyclic loading test on one ordinary concrete small hollow block wall and five walls strengthened with HPFL.The test results showed that the ultimate bearing capacity and ductility of the reinforced walls were improved.In particular, the cracking load of walls reinforced with HPFL by the means of ring beam-structural column were greatly improved with full development of cracks and full hysteresis curve, greatly improving the capability of energy consumption.In addition, considering the test results, the existing research and analysis, the shear capacity calculation formulas of concrete small-sized hollow block masonry reinforced with HPFL were put forward . The formulas coincided well with the experimental results, available for practical design reference.更多还原