Detail of GB 50040-1996

Introduction of GB 50040-1996

1 General Provisions 1.0.1 This specification has been formulated for the purpose to implement the state policy of technical economy to ensure engineering quality by selecting reasonable kinetic parameters and foundation form, thus making technology advanced, economic, safe and fit for purpose. 1.0.2 This specification applies for foundation design of various dynamic machines, namely: (1) Piston compressor; (2) Steam turbine unit and motor; (3) Turbine compressor; (4) Crusher and grinder; (5) Impact machine (forging hammer and drop hammer); (6) Hot dye forging press; (7) Metal-cutting lathe. This specification does not apply to foundation design of dynamic machine on building floors. 1.0.3 In addition to this specification, foundation design shall also meet other currently applicable state standards and codes. 2. Terminology and Signs 2.1 Terminology 2.1.1 Foundation Set The entire dynamic machine foundation with all machines, aux. equipment and backfill on top. 2.1.2 Equivalent Load Static load equivalent to dynamic load exerted on the original vibration system, adopted to facilitate analysis. 2.1.3 Frame Type Foundation Foundation formed by connecting top layer beams/plates and columns and bottom plates. 2.1.4 Wall Type Foundation Foundation formed by connecting top plates, walls and bottom plates. 2.1.5 Rigidity of Subsoil The ability of foundation to resist deform, value equals to the ratio of force/torque exerted on foundation with line/angle deform caused thereby. 2.2 Signs 2.2.1 Action and action effect Pz — Vertical interference force on machine Px — Horizontal interference force on machine P — Average designed static pressure on foundation bottom surface Mφ — Rotary interference torque on machine Mψ — Twisting interference torque on machine Az — Vertical vibration line displacement at center of gravity of foundation set Ax — Horizontal vibration line displacement at center of gravity of foundation set or that of foundation member Aφ — Rotary vibration angle displacement of foundation Aψ — Twisting vibration angle displacement of foundation Axφ — Horizontal vibration line displacement of foundation top plane control point under the eccentric action by horizontal interference force Px, torque Mφ and vertical interference force Pz Axψ — Vertical vibration line displacement of foundation top plane control point under the eccentric action by horizontal interference force Px, torque Mφ and vertical interference force Pz ω — Circular frequency of interference force on machine ωnz — Intrinsic vertical circular frequency of foundation set ωnx — Intrinsic horizontal circular frequency of foundation set ωnφ — Intrinsic rotary circular frequency of foundation set ωnψ — Intrinsic twisting circular frequency of foundation set ωn1 — Foundation set intrinsic circular frequency for horizontal rotary coupled vibration type I ωn2 — Foundation set intrinsic circular frequency for horizontal rotary coupled vibration type II a — Foundation vibration acceleration V — Foundation vibration speed 2.2.2 Calculation Indices Cz — Natural foundation compressive rigidity coefficient Cφ — Natural foundation flexural rigidity coefficient Cx — Natural foundation shear rigidity coefficient Cψ — Natural foundation torsion rigidity coefficient Cpz — Equivalent compressive rigidity coefficient of pile tip earth Cpτ — Equivalent shear rigidity coefficient of earth layers around pile Kz — Natural foundation compressive rigidity Kφ — Natural foundation flexural rigidity Kx — Natural foundation shear rigidity Kψ — Natural foundation torsion rigidity Kpz — Pile foundation compressive rigidity Kpφ — Pile foundation flexural rigidity Kpx — Pile foundation shear rigidity Kpψ — Pile foundation torsion rigidity ξz — Natural foundation vertical damping ratio ξxφ1 — Natural foundation damping ratio for horizontal rotary coupled vibration type I ξxφ2 — Natural foundation damping ratio for horizontal rotary coupled vibration type II ξψ — Natural foundation twisting damping ratio ξpz — Pile foundation vertical damping ratio ξpxφ1 — Pile foundation damping ratio for horizontal rotary coupled vibration type I ξpxφ2 — Pile foundation damping ratio for horizontal rotary coupled vibration type II ξpφ — Pile foundation twisting damping ratio fk — standard load bearing capacity for earth foundation f — Designed load bearing capacity for earth foundation [A] — Allowed vibration linear displacement for foundation [V] — Allowed vibration speed for foundation [a] — Allowed vibration acceleration for foundation m — Mass of foundation set 2.2.3 Geometric parameters A — Foundation bottom area Ap — Pile cross section I — Moment of inertia about axis through center of form of foundation bottom plane J — Moment of inertia of foundation set about axis of center of gravity Iz — Polar moment of inertia about axis through center of form of foundation bottom plane Jz — Polar moment of inertia of foundation set about axis of center of gravity h1 — Distance of center of gravity of foundation set to top plane of foundation h2 — Distance of center of gravity of foundation set to bottom plane of foundation 2.2.4 Calculation Coefficients and others αf — Dynamic reduction coefficient of earth foundation load bearing capacity αz — Increase coefficient of earth foundation compressive rigidity by foundation burying depth action αxφ — Increase coefficient of earth foundation shear, flexural and torsion rigidity by foundation burying depth action βz — Increase coefficient of vertical damping ratio by foundation burying depth action βxφ — Increase coefficient of damping ratio for horizontal rotary coupled vibration by foundation burying depth action δb — Foundation burying depth ratio 3 Basic Design Requirements 3.1 General Requirements 3.1.1 Following information should be available at time of foundation design: 1) type of machine, rotation speed, power rating, size and outline/dimensions drawing; 2) weight of machine and position of center of gravity; 3) outline drawing of machine pedestal, aux. equipment, piping location; dimensions of pit, ditch and holes; thickness of grouting, positions of anchor bolts and embedded parts, etc.; 4) interference force and torque on machine and their directions; 5) positions of foundation and foundation drawing of neighboring buildings; 6) geological survey information and earth foundation kinetic testing information of construction site.; 3.1.2 Dynamic machine foundation should be separated from building foundation, upper structure and concrete ground surface. 3.1.3 When major vibration of machine exists due to connection with piping, vibration isolating measures shall be taken where piping contacts building. 3.1.4 When vibration of machine foundation adversely affects nearby personnel, precision equipment, instrumentation, factory production or buildings, vibration isolating measures shall be taken. The effect of vibration of low frequency machine and impact machine on plant house structure should meet Appendix A of this specification. 3.1.5 Dynamic machine foundation design must not create detrimental uneven subsidence. 3.1.6 When dynamic machine foundation and neighboring building foundation are on natural foundation, their burying depths can be at different elevations provided construction requirements can be met and backfill for this difference is well compacted. 3.1.7 When dynamic machine foundation sits on fairly integral rock, pile foundation can be adopted with the exception of dynamic foundation for forging hammers and drop hammers. In this case, foundation design shall meet Appendix B of this specification. 3.1.8 The distance between pedestal rim and foundation rim is preferably not less than 100mm. With the exception of forging hammer foundation, secondary grouting of thickness not less than 25 mm shall be provided beforehand under the machine pedestal. This should be fill-compacted by slight expansion concrete and combined with concrete foundation surface.

Contents of GB 50040-1996

Table of Contents 1. General Provisions 2. Terminology and Signs 2.1 Terminology 2.2 Signs 3. Basic Design Requirements 3.1 General Requirements 3.2 Calculation rules for earth foundation and machine foundation 3.3 Dynamic characteristic parameters of earth foundation 4. Piston Compressor Foundation 4.1 General Specification 4.2 Structural Requirements 4.3 Kinetic Calculation 4.4 Joint Foundation 4.5 Simplified Calculation 5. Turbine Unit & Motor Foundations 5.1 General Provisions 5.2 Kinetic Calculations for Frame Type Foundation 5.3 Load Bearing Capacity Calculation for Frame Type Foundation 5.4 Design of Low Speed Motor Foundation 6. Foundation of turbine compressor 6.1 General 6.2 Structure requirements 6.3 Dynamic force calculation 6.4 Calculation of bearing capacity of frame foundation 7 Crusher and mill foundation 7.1 Crusher foundation 7.2 Mill foundation 8. Impact machine foundation 8.1 Hammer foundation 8.2 Drop hammer foundation 9 Foundation of hot die forging press 9.1 General 9.2 Structural requirements 9.3 Dynamic force calculation 10 Foundation for metal-cutting machine Appendix A Influence of the vibration of low frequency and impact machines on the building structure Appendix B Design of anchor pile (rod) foundation Appendix C Dynamic force calculation of frame foundation Appendix D Strength calculation and structure of positive cone shell hammer foundations Appendix E Calculation of ground vibration weakening Appendix F Calculation of dynamic coefficient with damp max of press foundation Appendix G Terminology of this code