Experimental And Applied Study On Raft Foundation Reinforced By Steel Fiber

Steel fiber reinforced concrete (SFRC) is superexcellent composites material. It develops continuously with its application. But the report which it is applied in foundation engineering is few, which is mainly because the mass of concrete in basement is large, and the construction cost improves if SFRC is wholly applied in basement. So it is quite important for SFRC to be used in those essential parts, such as the vicinity of frame column or shear wall in basement. The SFRC greatly improves the punching shear carrying capacity in raft foundation, or reduces the thickness of raft foundation in the same load. This in turn offers convenience in construction, reduces hydration heat in concrete and saves investments. This paper also gives the method of spreading steel fiber by layering on site, which can be widely applied in product concrete at present.According to experimental and applied study on raft foundation reinforced by steel fiber, the paper mainly gives researches as follows:1 .The experiment of concrete slab reinforced by steel fiber is made. The capacity between normal concrete and SFRC slab is compared. In addition, slabs made by different construction method between spreading steel fiber by layering and mixing fiber in advance are compared.2.The punching shear carrying capacity could be divided into concrete action and reinforcement dowel action in theory. The paper also gives factors influencing punching shear capacity both normal slabs and SFRC slabs. In addition, the strengthening principle for slab reinforced by random short steel fiber is illumined, which can be as a basic for SFRC's applying in engineering.3.In prevail algorithm for raft foundation , the paper indicates that the most economic and suitable method is finite element analysis while accounting for rigidity of upset structure. The paper also gives practical design and calculation for raft foundation reinforced by steel fiber partly.4.For a particular engineering, some targets are compared between normal raft foundation and raft foundation reinforced by steel fiber, which proves that the latter is superiority.