Reference Project: Twarqi Steel MillMachine FoundationBased on their operating frequency, machine may be divided in to three categories and respective foundation type can be used as shown in table.Type of MachinesTypical Operating Frequency Typical Machines IncludeFoundation Type used

Low to medium frequency0-500 rpm

Large Reciprocating engines Compressors & blowers Block type with large contact area with soil

Medium to high frequency300-1000 rpm Medium sized reciprocating Engines for e.g. (Diesel & Gas Engines Block type or suitable elastic pads

Very High frequencyGreater than 1000 rpm High speed internal Combustion Engine Electric Motors Turbo Generator sets Massive Block foundation usedFramed type foundation

Characteristics of Block Type Foundation: A block foundation has a large mass and,therefore, a smaller natural frequency. If a relatively lighter foundation is desired,a box or a caisson type foundation may beprovided. The mass of the foundation is reduced andits natural frequency increases.Design Analysis:Code & References Used for RC design & Dynamic Analysis. ACI 318-05: Building Code Requirements for Structural Concrete. Text Book and Reference Manuals Handbook of machine foundation by P.Srinivasulu and C.V Vaidyanathan. Foundation Analysis and Design by J. E Bowles.Software Used for Analysis:Following are the list of computer analysis used for structural analysis or cross checking the manual design by using in-house spreadsheets. STAAD.Pro SAFE ETABS In-house Spreadsheets.Loads Used to Design: Static Load Mainly includes the dead load of the structure can be calculated by using structural dimension and unit weight Dead load of machine provided by the Vendor.

Dynamic Load Dynamic load of the machinery can be taken as % of its dead weight conservatively.Dynamic Analysis: Dynamic analysis of the foundation is done by refereeing Handbook of machine foundation by P.Srinivasulu and C.V Vaidyanathan. For this particular foundation the Vendor Supplied Vibrational Characteristics are used. Following Checks is done for ensuring the safe behavior of foundation against dynamic response. Check for Eccentricity. Calculation of Natural Frequencies of Foundation for various mode. Vertical Translation Sliding and rocking TwistingAll these checks are done by using the design aid procedure describe in the above mentioned reference Hand Book.Stability Checks:Stability of the foundation is ensure by conducting the following stability checks. Bearing Capacity check (Manually & by using SAFE software) Sliding check for Horizontal force. (Earthquake)From the practical point of view, the following requirements should be fulfilled:1. The groundwater table should be as low as possible and groundwater level deeper by at least one-fourth of the width of foundation below the base plane. This limits the vibration propagation, groundwater being a good conductor of vibration waves.2. Machine foundations should be separated from adjacent building components by means of expansion joints.3. Any steam or hot air pipes, embedded in the foundation must be properly isolated.4. The foundation must be protected from machine oil by means of acid-resisting coating or suitable chemical treatment.5. Machine foundations should be taken to a level lower than the level of the foundations of adjoining buildings.