| With the high development of the construction industry in urban and countryside area, high formwork supporting system is being applied more and more extensively to cast-in-place concrete structure. The high formwork supporting system with fastener-style steel pipe, a style of frame system, is used most widely and in the largest quantity. However, because of some uncertain and unsafe factors during designing calculation and construction, collapses of the high formwork supporting system are frequent, which is harmful to the safety of constructing and the performance of building.When it comes to the designing calculation of the high formwork supporting system with fastener-style steel pipe, there are three apparent bugs in present standard. First, the calculation of load does not take the impulsive force bringing by pumping concrete into account. Second, the calculation of vertical struts doesn't have needed degree of safety. Third, the structures of the frame system were so loose that it could make the frame a stable no-geometric structure , in stead of a stable geometric structure. Furthermore, there are also two shortcomings in existing research achievements. Firstly, these researches always emphasize the stability of vertical struts and pay little attention to foundation's design. Secondly, these researches focus on the calculation method and little make a deep and systematic analysis on the managing process.According to the experience getting from a typical project, this article tries to provide a solution. In the project, the author established a QC group and carried out a PDCA cycle which aimed at ensuring the safety of the preload-stressed concrete box beam high formwork system. By using the cause and effect system diagram, the QC group distinguishes 13 terminal elements which can cause the preload-stressed concrete box beam high formwork system to lose stability and defines seven of them as the key elements in the project and then raised the corresponding solutions. After being put into practice, these solutions are proved to be effective. The construction process of preload-stressed box beam's is accomplished smoothly, which set a good example to other similar projects. Basing on the thirteen terminal elements analyzed from the project above, consequently, the author carries out a study on fifty high-formwork projects in Guangxi. The study shows that in the percent of pass, two items are lower than 60%, e.g. thicknessless of steel tube and no equipping moment tool, moreover, the percent of pass of these two items ranking from 0 to 2%, on which government departments, engineering supervision agencies and engineering companies need to concentrate more attention and take effective measures. 2 items have a percent of pass ranking from 60% to 80%, e.g. having no detailed joint structural measure and the curve of steel tube, which needed to be paying a common attention to. The other nine items'pass percent was better than 80%, to which a proper concentration was enough.After research, this article sums up three bugs existing in present standard and proposes amendments. By practical building, the author provides a whole case on how to design a high formwork supporting system, which set a good example to the other projects. By establishing the QC group and carrying out the PDCA cycle, the thirteen terminal elements that affect the quality of high formwork supporting system constructing are distinguished and corresponding solutions are brought up. By the survey of fifty engineering projects, the variability law of the thirteen terminal elements is found out; according which the author proposes the measures that government departments, engineering supervision agencies and engineering companies should take. This article, in a word, would provide scientific basis for the safety, high efficiency and economical work of the high formwork supporting system with fastener-style steel pipe. It also provides an available reference to the safe construction of civil building. |
PDF Full Text Request