The Experimental Research Of Mechanical Behavior Of Mass Concrete Equipment Foundation

Equipment Foundation is widely used in the construction of the metallurgical industry, which has its own trait. It's usually mass concrete. As we know, pouring the concrete will release large hydration heat. Therefore, the foundation will have a high temperature stress. At the same time, the impact of high temperature of the equipment above can not be ignored. Furthermore, the foundation will bear a lot of external load. So the working condition of the Equipment Foundation is complicate. At present, there is not any codes used to design, the Equipment Foundation is often designed as the general foundation referring to Concrete Structure Design Code (GB50010-2002). The forced steel bar at the bottom is designed according to the external load and minimum reinforcement ratio and the other entire bar is designed to the constructional reinforcement. It's quite different from the features of the foundation. So, it is necessary to have a special study on reinforcement distribution. In this paper, an experimental study of Equipment Foundation is introduced.First of all, the models, which include 3 specimens of blast furnace foundation and 2 specimens of the hot-blast stove foundation, were established. Considering the symmetry of the specimens, the reinforcement of the same reinforcement ratio but different diameter or grade was confederated. The influence of the temperature and the ground conditions was considered. Through the analysis of the strain curves of the concrete and reinforcement, the development of cracks and the damage of the specimens, the effect of the temperature and the mechanical behavior of the foundation under different conditions were grasped preliminary. The main conclusions follow:①Through the monitoring of the temperature, the distribution of the hydration heat in the specimens was get preliminary.②The impact of the external temperature was confined to the contact position. The external temperature has very little effect on the mechanical behavior.③The distribution of the lateral reinforcement on the top truncated cone of the blast furnace foundation and the position influenced by the external temperature on the hot blast stove foundation should be strengthened, considersing the effect of the external temperature besides the hydration and the shrinkage.④Through the analysis of the phenomenon and the test data, the transfer mechanism of the blast furnace foundation and the hot-blast stove foundation can be approximately equivalent to the girder and space truss model.⑤Negative moment can be found around the supports. The specimen usually is weakness at the variable cross-section.In view of the above conclusions, some advice for Equipment Foundation follows: According to the distribution of the hydration heat, it's necessary to put some reinforced net in the foundation; It's feasible to reduce the minimum reinforcement rate appropriately; the distribution of the reinforcement at the bottom of the foundation should not be uniform, but optimized according to the strut-and-tie theory; It is suggested that the steel bar within the range of the pile diameter should be strengthen; the top constructional reinforcements at the large negative bending regions and the variable cross-section should be strengthen too.