| The bond-retarded prestressing technology not only has the advantages of convenient construction and flexible reinforcement of the non-bonded system,but also has the characteristics of cohesive prestressed steel bars and concrete force coordination,and durability can be easily guaranteed.The hydraulic prestressed concrete pressure tunnel and sewage treatment tank have poor structural environmental conditions and high anti-corrosion requirements.The application of bond-retarded prestress technology has inherent advantages.In this paper,combined with a bond-retarded prestressed concrete sedimentation tank structure in a city of Gansu Province.ANSYS software is used to build the prestressed tension,the full water level,the normal operation and the empty pool stage.The system simulation analysis was carried out to analyze the stress mechanism of the bond-retarded prestressed concrete sedimentation tank under various working conditions,and the feasibility and applicability of the bond-retarded prestressing technology in the concrete sedimentation tank structure were verified.The optimal tensioning scheme of prestressed tendons is proposed,and the tension time of the bond-retarded prestressed steel bars during the application period is determined.The effects of temperature action and foundation uniformity on the structure of the sedimentation tank are compared and analyzed.Reasonable suggestions and references are proposed for the structural design and construction process of the prestressed system.The main results are as follows:1)Determine the optimal tensioning scheme for the prestressing tendons,that is,layering and pulling in the top-bottom order.2)The optimal prestressing tension time is proposed,that is,the optimum tension time of the bond-retarded prestressing tendons in the curing period is 15 days,and the prestressing tendons should be stretched within 60 days,at the latest.Should exceed 75 days.3)In view of the influence of temperature drop in winter,the distribution law of the internal force of the circumferential effect and the longitudinal direction of the sedimentation tank is clarified,and the countermeasures for solving the excessive temperature effect are proposed,that is,the thermal insulation measures are adopted or the steel bar method against temperature effect is added.4)The distribution law of internal force when the sedimentation tank structure is located in the geologically heterogeneous soil layer is studied,and the most unfavorable stress condition is clarified.The control measures to control the influence of uneven soil layer are proposed. |
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