The Analysis On Thermal Stress Of Overlong Basement Wall And Its System Development

In recent years, basement was wide used by developers and designers, its scale are becoming larger, while construction of basement wall cracking problems have become increasingly prominent. The crack, not only influence the appearance but also the structural durability, and may lead to leakage. However, for the cracking problem during concrete construction, there are no relative generally applicable theoretical solution and provisions, so the study of the concrete cracking problems in the construction is very important.The computation theory for the transient state temperature field and the stress field has been analyzed, the heat conductive equation has been established, the transient state temperature field and the temperature continuous variation stress finite element solution has also been inferred in this article. The simulation analysis system of the overlong concrete wall has been developed with UIDL and APDL of ANSYS software which provided re-development tools. Based on the thermal-structure coupling analysis theory, the system program is accomplished by using APDL command flow for temperature field and the stress field simulation analysis. The factor effect due to the removing model, the change of environment temperature and the variation of concrete property with time during construction, has been simulated in this system.Because the construction period concrete elasticity coefficient is diversified with time, the temperature stress results calculated in ANSYS with traditional method are not agree with reality. Considering the important factor, the increase method to calculate concrete temperature stress is used in this article. Finally, based on one project, the simulation computation has been carried to the wall temperature field and the stress field. In order to further study the change rules of the wall temperature field and the stress field, the knots temperature and stress value are chosen at the different position apart from the wall center, the wall height place and the thickness place. The variation rule has been obtained through the comparative analysis. Theinfluence to the wall temperature field and the stress field such as the template type, the environment temperature, the mixture ratio and the concrete intensity rank, are analyzed.Using the developed menus and the dialog boxes with UIDL and APDL language in ANSYS, establish the finite element model, the division grid, the realization computation analysis automation and the result visualization conveniently. This development of the system can reduce the repetition work greatly, enhance the application efficiency, unify and simplify application method, establishe the specialized database and the specialized appraisal system.Through the above research work, the effective proposals are given in this article about the design aspect, the construction aspect, the material and the mixture ratio aspect.