This paper describes the development of the turbine-generator support for a Floating Nuclear Plant (FNP). It discusses some of the alternative configurations considered and describes the basis for the selection of a spring-mounted concrete table top. The paper covers the methodology and results of static and dynamic analyses performed to evaluate the behavior of the turbine generator on the spring-mounted concrete table top supported by the main deck of the steel platform.

A dynamic analysis of an Induced Draft Fan and Foundation, subjected to unbalanced rotor loadings, is described and discussed. The installation selected for analysis is supported on piles, and consists of a reinforced concrete foundation and bearing pedestals, fan motor, fan, housing, and exhaust duct (evase’). The modeling techniques presented by the author in this case study will illustrate a method for the Design Engineer to completely analyze complex coupled systems involving both oil film and pile/soil stiffness and damping. The techniques presented do not require that the structural analysis computer program have discrete element damping (dashpot) capabilities. The model is all inclusive and can be used for both static and dynamic analysis. Dynamic responses, particularly modal frequencies and peak-to-peak journal bearing amplitudes of motion are compared with those calculated from relatively simplified lumped mass stick models of the same installation. Insight is gained into the dynamic behavior of the coupled system and the comparison study points out the limitations of the stick model responses. This paper presents a case study of an Induced Draft Pan and Foundation with special emphasis on the computer modeling techniques utilized. The model illustrated idealizes the COMPLETE system installation, and as such, is capable of directly predicting static deflections and internal forces, as well as coupled dynamic responses to earthquake and unbalanced rotor loads. The modeling techniques described are readily adaptable to commercially available structural analysis programs with finite element capabilities (i.e., Nastran, Strudl, Stardyne, Ansys).

In the first part, the paper critically reviews the current state of art on the analysis and design of typical types of machine foundations. The uncertainties in the design data and paucity of essential information required for a rational design are highlighted. The need to study the geotechnical features and other environmental factors at the proposed site of a machine foundation is emphasized. The various aspects of the problem of a machine foundation are illustrated with the explanation of five typical case studies selected from authors' experience in this line of work. The paper also underlines the need for a close co-ordination between the civil and mechanical engineers responsible for the installation of machine foundation right from the early stages of planning.

This paper describes the design and construction of low-tuned, spring supported foundations for boiler feedpumps units installed in the Big Stone coal-fired power plant in South Dakota. Each system consists of a variable speed 9,500 HP (7084 Kw) steam turbine which drives a pair of feedpumps and is mounted on a prestressed concrete inertia block set on steel springs. This vibration isolation design required dynamic analysis of the inertia block systems since the variable speed pumps could present a range of forcing frequencies and hence a series of possible resonances. The concrete inertia blocks were prestressed in order to prevent cracking which could cause significant changes in the dynamic behavior. The concrete inertia blocks were fabricated and prestressed outside the turbine building. Each weighed about 96 tons (854 kN) and they were lifted into position on their steel springs on the operating floor level. The flexible isolation of the inertia blocks from the building floor facilitated the alignment of the machinery and the attachment of the piping. Vibration tests were conducted during plant start-up in order to anticipate potential problems and to verify dynamic characteristics. These units have now performed successfully for several years.

This paper is a case study of pneuniatic isolation systeliis in large automobile recycling machines. Machines of increasing size and power, plus a public that is increasingly insistent on its right to an environment free of noise and vibration, equal potential problenis for recycling plants. In response to this situation, a hammermill/shredder operation making successful use of pneunlatic isolation has been designed and constructed. The first, and still the largest, operation of its kind, the operation has demonstrated a valuable method of containing machine vibrations that might otherwise ignite hostility in the surrounding community and quite possibly bring on expensive legal action. The particular system described was installed in a 4,000-horsepower hammermill at an Indiana recycling firm. Besides effecting a more than 90 percent reduction in ground vibration, the system allows for easier and more efficient machine leveling and includes systems to warn of and localize pressure loss, to minimize routine mechanical shock, and to contain extraordinary shocks resulting from exploding gas tanks and loss of hammers within the machine. The system has now been in use for two years with no reported problems.