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The accumulation and incineration of waste tires have caused great damage to the environment. Therefore, recycling waste tires efficiently and economically has become an important issue in protecting world resources and the environment. In this study, 5%, 10%, and 15% rubber particles were used to replace fine sand in concrete, and basalt fibers (0.1%, 0.2%, and 0.3%) and polypropylene fibers (0.1%, 0.15%, and 0.2%) were added to rubber concrete to prepare hybrid fiber rubber concrete (HFRC). The experiments investigated the changes of mechanical properties of basalt (BF), polypropylene (PPF) fibers, and rubber particles when they were blended into concrete respectively, and the degree of influence of each factor on the mechanical and carbonation resistance of HFRC was investigated based on the orthogonal test. The results show that the rubber concrete’s mechanical and carbonation properties are improved to varying degrees after adding hybrid fibers. When the basalt fiber content is 0.2% and the polypropylene fiber content is 0.15%, the overall mechanical properties of HFRC reach the best state. When the basalt fiber content is 0.2%, the polypropylene fiber content is 0.15%, and the rubber content is 5%, the carbonation resistance of HFRC is the most ideal. In addition, the microstructure of HFRC was observed by scanning electron microscope.

To provide bases for the tests, design and construction of deep beams, the improved robust design method and the new signal-to-noise ratio were employed. Parameters including the shear span ratio, the concrete strength, the yield strength of horizontal hoop, and the yield strength of vertical hoop were taken into account. The shear strength of deep beams and the factors affecting it were analyzed by the softened truss model and the improved robust design method, respectively. The results show that the strength of concrete has the largest influence on the shear strength of component, the next is the shear span ratio, the yield strength of horizontal reinforce and the yield strength of vertical reinforce have the least influence on it. The analysis result of improved robust design method agrees better with the test result compared with Taguchi method, and it is more accurate and more convenient than Taguchi method. [ABSTRACT FROM AUTHOR]

To research the dynamic analysis problem of vertical non -- uniform high -- rise structure and towering structure, flexural vibrations were taken as examples with the consideration of combined action of superstructure and foundation as well as the action of rotation. Then the non -- uniform continuous towering structure was simplified to segmented uniform continuous structure, and the partial differential equation was turned into the ordinary differential equation by utilizing the orthogonality of vibration mode. A model of vertical segmented uniform continuous structure was presented and applied to the establishment of dynamic equation. The method is applicable in the dynamic analysis of non -- uniform structure. [ABSTRACT FROM AUTHOR]