Návrh anti-seizmických opatření v konstrukci vertikálního HRSG kotle

Abstract

In general, technological structures are of marginal research interest in the theory of structures. There are countless technological structures as well as countless kinds of technologies which are supported by these structures. In addition basic knowledge of a certain technology is essential, for qualified research in this area. This work aims to partially balance this deficit. Its central theme is the structure of waste heat vertical boilers. These are widespread equipment. All around the world, the supporting structures of this equipment are designed conceptually similarly and they also make use of similar details in the connections of boiler technology to the supporting structure.

This work is focused on determining the value of mechanical damping of a suspended waste heat vertical boiler. On the basis of experimental measurements on a scale model, values of logarithmic decrement of damping for several modifications of the boiler are determined. These modifications represent the individual details of the vertical boiler. In these details the vertical boilers differ from other building structures. Each modification thus represents one special feature of a vertical boiler’s structure. The proportional change in the structure damping of a certain modification compared to bare structure without a boiler expresses the relative contribution of a certain detail to the overall damping. Verification of results obtained by measurements on a scale model is made using measurements on an already implemented vertical boiler.

Furthermore, this work deals with material solution of energy dissipation details in seismic applications with a focus on the details on the principle of hysteresis yield exceeding. It evaluates the usability of S235 structural steel and DD11 steel for application in such details. In structures with energy dissipation details of this type, it is usual to combine multiple quality of steel. For a main frame, steel with higher yield strength is used. For details designed for hysteresis energy dissipation, on the contrary, it is useful to use steel with a yield strength as low as possible. In Europe, primarily the combination of steel S235 and S355 seems to be optimal. Since the whole design philosophy of such structures is based on the condition of exceeding the yield strength in energy dissipation details, the statistical variance of mechanical qualities of materials can pose a risk. Part of this work is therefore focused on probability risk assessment, failure to yield strength in the energy dissipation details in the aforementioned combination of S235 and S355.