Displacement amplification method and apparatus for passive energy dissipation in seismic applications

• US 20010054785A1
• Filed: 06/15/2001
• Published: 12/27/2001
• Est. Priority Date: 06/16/2000
• Status: Active Grant

• Current Assignee: Stefano Berton
• Original Assignee: Stefano Berton
• Inventors: Berton, Stefano
• Granted Patent: US 6,672,573 B2
• Time in Patent Office: Days
• US Class Current: 267/136
• CPC Class Codes: E04H 9/0235 Anti-seismic devices with hydraulic or pneumatic damping
• CPC Class Codes: E04H 9/0237 Structural braces with damping devices
• CPC Class Codes: E04H 9/028 Earthquake withstanding shelters

Abstract

An apparatus and method of dissipating inter floor seismic energy within buildings and other large structures which are subject mechanical deformation in response to seismic activity, wind shear, vibration, and so forth. The present invention provides displacement amplification methods and apparatus which increase the dissipation of seismic energy that is coupled from the building under deformation to a seismic damper. By way of example, the displacement amplifier is exemplified in a number of embodiments that utilize mechanical lever arms, gear sets, and combination amplifier/dampers to amplify energy dissipation.

Claims

1. An apparatus for placement within the gravity frame of a structure which amplifies inter story structural displacements to increase passive energy dissipation in seismic applications, comprising:

(a) a reaction frame rigidly coupled to a base level;

(b) means for amplifying mechanical displacement coupled between said reaction frame and said gravity frame; and

(c) a damping device coupled to the mechanical output of said displacement amplifier.

2. An apparatus as recited in

claim 1

, wherein said mechanical displacement amplifying means comprises a pivoting lever having unequal length arms.

3. An apparatus as recited in

claim 2

, wherein the displacement applied to the damper is amplified by the ratio of the length of the longer arm to the shorter arm within the pivoting lever.

4. An apparatus as recited in

claim 2

, wherein said pivoting lever has a first arm attached between said reaction frame and said gravity frame which is subject to distortion in relation to the reaction frame, and a second arm, longer than said first arm, which is coupled to said damper device.

5. An apparatus as recited in

claim 4

, wherein the pivoting lever is straight, having coupling points on the first arm and second arm that are collinear with the pivot point of said lever arm.

6. An apparatus as recited in

claim 4

, wherein the pivoting lever arm has coupling points on the first arm and second arm that are non-collinear with the pivot point of said lever arm.

7. An apparatus as recited in

claim 2

, wherein the pivot of said lever is attached to said gravity frame and has a first arm coupled to said reaction frame and a second arm, longer than said first arm, which is coupled to a damping device.

8. An apparatus as recited in

claim 7

, wherein the arm couplings comprise pivotal couplings.

9. An apparatus as recited in

claim 8

, wherein the pivotal couplings comprise:

(a) an elongated hole near the terminating end of each arm; and

(b) a pin configured for slidable retention within said elongated hole.

10. An apparatus as recited in

claim 1

, wherein the mechanical displacement applied to the damper is amplified by the ratio of the diameter of a larger gear coupled to the damper in relation to the diameter of a smaller gear coupled to a linear coupling member subject to the relative displacement of the gravity frame relation to the position of the reaction frame, wherein said smaller gear is connected for substantially concentric rotation with said larger gear.

11. An apparatus as recited in

claim 1

, wherein said mechanical displacement amplifying means comprises:

(a) a generally concentric rotating gearset having a first gear connected to a larger second gear;

(b) said first gear being coupled to a first linear coupling member subject to the relative linear displacement of the gravity frame in relation to the reaction frame; and

(c) said second gear coupled to a second linear coupling member which is attached to a damping device.

12. An apparatus as recited in

claim 7

, wherein the coupling between the gears and the linear coupling members comprises a rack-pinion coupling mechanism.

13. An apparatus as recited in

claim 1

, wherein said mechanical displacement amplifying means is combined with said damping device within a rotating damper, comprising:

(a) a linear coupling member subject to the displacement of the gravity frame in relation to the reaction frame;

(b) a gear-driven propeller coupled to said linear coupling member and configured to amplify the motion of the linear coupling member into the rotational motion of said propeller; and

(c) a housing filled with fluid surrounding said propeller.

14. An apparatus as recited in

claim 13

, wherein said coupling between said linear coupling member and said gear drive propeller is provided by a rack-pinion coupling mechanism.

15. An apparatus as recited in

claim 14

, wherein said linear coupling member is configured with multiple pinions for driving multiple gear-driven propellers.

16. An apparatus as recited in

claim 15

, wherein said multiple gear-driven propellers are configured for counter-rotation in close proximity to one another within said fluid filled housing.

17. An apparatus as recited in

claim 1

, wherein said damper device mechanism is an energy dissipation device for damping mechanical movement.

18. An apparatus as recited in

claim 1

, wherein said damper mechanism comprises a fluid viscous damper.

19. An apparatus as recited in

claim 1

, wherein said damper mechanism comprises a friction dampers

20. An apparatus as recited in

claim 1

, wherein said damper mechanism comprises a viscous elastic dampers.

21. An apparatus as recited in

claim 1

, wherein said reaction frame comprises a triangular structure configured for positioning beneath a horizontal support of said gravity frame.

22. An apparatus as recited in

claim 21

, wherein said reaction frame further comprises a slidable coupling attached to said triangular structure which supports said horizontal support within said gravity frame and restricts motion therein to substantially lateral movements.

23. An apparatus as recited in

claim 22

, wherein said slidable coupling incorporates rollers configured to allow lateral displacements of said horizontal support.

24. An apparatus as recited in

claim 21

, wherein said triangular structure comprises a pair of legs rigidly having proximal ends attached to the base level and distal ends fixedly joined to one another to provide a support for said mechanical displacement amplifier.

25. An apparatus as recited in

claim 21

, wherein said damper device is mounted within said triangular structure.

26. An apparatus as recited in

claim 1

, wherein said damper device is mounted within the gravity frame.

27. An apparatus as recited in

claim 1

, wherein said reaction frame comprises:

(a) a housing rigidly attached to the base level;

(b) said housing configured to receive said means for amplifying mechanical displacement;

(c) a diagonal support member having a distal end configured for attachment to said gravity frame at a selected location;

(d) said diagonal support member having a proximal end configured for attachment to said means for amplifying mechanical displacement such that displacement of said gravity frame at said location will induce movement of said diagonal support.

28. An apparatus for placement within a gravity frame of a structure which passively dissipates energy from structural displacements of said gravity frame, comprising:

(a) a reaction frame rigidly coupled to a base level;

(b) a mechanical displacement amplifier having an input coupled between said reaction frame and said gravity frame; and

(c) a damper assembly coupled to the mechanical output of said displacement amplifier.

29. An apparatus as recited in

claim 28

, wherein the mechanical displacement amplifier comprises:

(a) a pivoting lever;

(b) said pivoting lever having a short arm receiving mechanical input; and

(c) said pivoting level having a longer arm from which mechanical output is generated.

30. An apparatus as recited in

claim 29

, wherein the pivoting lever is straight, having coupling points which are collinear with the pivot point.

31. An apparatus as recited in

claim 29

, wherein the pivoting lever arm has coupling points which are non-collinear with the pivot point.

32. An apparatus as recited in

claim 29

, wherein the pivot of said pivoting lever is configured for attachment to the gravity frame and whose first arm is configured for coupling to said reaction frame, and whose second arm, longer than said first arm, is configured for coupling to a damping assembly.

33. An apparatus as recited in

claim 29

, wherein the arm couplings comprise pivotal couplings.

34. An apparatus as recited in

claim 33

, wherein pivotal couplings comprise:

(a) an elongated hole near the end of each arm; and

(b) a pin configured for slidable retention within said elongated hole.

35. An apparatus as recited in

claim 29

, wherein the displacement applied to the damper assembly is amplified by the ratio of length of the longer arm to the shorter arm.

36. An apparatus as recited in

claim 29

,

wherein the small arm of said lever is attached between said reaction frame and said gravity frame;

wherein said gravity frame is subject to distortion in relation to the reaction frame; and

wherein the longer arm is coupled to said damper assembly.

37. An apparatus as recited in

claim 29

,

wherein the pivot of said lever is attached to said gravity frame,

wherein said shorter arm is coupled to said reaction frame, and

wherein said longer arm is coupled to the damping assembly.

38. An apparatus as recited in

claim 28

, wherein the mechanical displacement amplifier comprises:

(a) a gearset which is substantially concentric and contains gears of different diameters;

(b) a first gear within said gearset coupled to a linear coupling member subject to the relative displacement of the gravity frame relation to the position of the reaction frame, and

(c) a second gear, of larger diameter than said first gear to amplify linear motion received therein, coupled to a linear coupling member which urges movement within said damping assembly.

39. An apparatus as recited in

claim 28

,

wherein said mechanical displacement amplifying means comprises a generally concentric rotating gearset having a first gear attached to a larger second gear,

wherein said first gear being coupled to a first linear coupling member subject to the relative linear displacement of the gravity frame in relation to the reaction frame, and

wherein said second gear coupled to a second linear coupling member which is attached to a damping assembly.

40. An apparatus as recited in

claim 39

, wherein the coupling between the first gear and the linear coupling member is provided by rack and pinion coupling.

41. An apparatus as recited in

claim 28

, wherein said mechanical displacement amplifier is combined with said damper assembly within a rotating damper, comprising:

(a) a linear coupling member subject to the relative displacement of the gravity frame in relation to the reaction frame;

(b) a gear-driven propeller coupled to said linear coupling member and configured to amplify the linear displacement of the linear coupling member into the rotational motion of said propeller; and

(c) a housing filled with viscous fluid surrounding said propeller.

42. An apparatus as recited in

claim 41

, wherein said coupling between said linear coupling member and said gear drive propeller is provided by a rack-pinion coupling.

43. An apparatus as recited in

claim 42

, wherein said linear coupling member is configured with multiple pinions for driving multiple gear-driven propellers.

44. An apparatus as recited in

claim 43

, wherein said multiple gear-driven propellers are configured for counter-rotation in close proximity to one another within said fluid filled housing.

45. An apparatus as recited in

claim 28

, wherein said damper assembly provides energy dissipation to damp the mechanical distortions of the gravity frame in relation to the reaction frame.

46. An apparatus as recited in

claim 28

, wherein said damper assembly comprises a fluid viscous damper.

47. An apparatus as recited in

claim 28

, wherein said damper assembly comprises a friction damper.

48. An apparatus as recited in

claim 28

, wherein said damper assembly comprises a viscous elastic dampers.

49. An apparatus as recited in

claim 28

, wherein said reaction frame comprises a triangular structure configured for positioning beneath a horizontal support of said gravity frame.

50. An apparatus as recited in

claim 49

, wherein said reaction frame further comprises a slidable coupling attached to said triangular structure which supports said horizontal support within said gravity frame and restricts motion therein to substantially lateral movements.

51. An apparatus as recited in

claim 50

, wherein said slidable coupling incorporates rollers configured to allow lateral displacements of said horizontal support.

52. An apparatus as recited in

claim 49

, wherein said triangular structure comprises a pair of legs rigidly having proximal ends attached to the base level and distal ends fixedly joined to one another to provide a support for said mechanical displacement amplifier.

53. An apparatus as recited in

claim 49

, wherein said damper device is mounted within said triangular structure.

54. An apparatus as recited in

claim 28

, wherein said damper device is mounted within the gravity frame.

55. An apparatus as recited in

claim 28

, wherein said reaction frame comprises:

(a) a housing rigidly attached to the base level;

(b) said housing configured to receive said mechanical displacement amplifier;

(c) a diagonal support member having a distal end configured for attachment to said gravity frame at a selected location;

(d) said diagonal support member having a proximal end configured for attachment to said mechanical displacement amplifier such that displacement of said gravity frame at said location will induce movement of said diagonal support.

56. A seismic isolator configured for attachment between a rigid structure and a flexible structure to dissipate seismic energy, comprising:

(a) means for mechanically amplifying movement of said flexible structure in relation to the position of said rigid structure; and

(b) a damper receiving the mechanical output of said mechanical amplifying means.

57. A seismic isolator as recited in

claim 56

, wherein the means for mechanical amplifying movement comprises:

(a) a pivoting lever;

(b) said pivoting lever having a small arm which receives mechanical input from the movement of the flexible structure; and

(c) said pivoting level having a larger arm from which amplified mechanical output is generated.

58. A seismic isolator as recited in

claim 57

, wherein the displacement being applied to the damper is amplified by the ratio of length of the longer arm to the shorter arm.

59. A seismic isolator as recited in

claim 57

, wherein said pivoting lever comprises:

(a) a rotating pivot configured for joining to said flexible structure;

(b) a short arm configured for coupling to said rigid structure, and

(c) a long arm configured for coupling to said damper.

60. A seismic isolator as recited in

claim 56

, wherein the means for mechanically amplifying movement, comprises:

(a) a concentric rotating gearset having gears of different diameters;

(b) a small diameter first gear within set gearset coupled to a linear coupling member subject to the motion of the flexible structure in relation to rigid structure, and

(c) a large diameter second gear which amplifies the motion received by said first gear and couples to a linear coupling member which is received by said damper to dissipate mechanical energy.

61. A seismic isolator as recited in

claim 56

, wherein the means for mechanically amplifying movement, comprises:

(a) a generally concentric rotating gearset having a first gear attached to a larger second gear;

(b) said first gear being coupled to a first linear coupling member subject to the motion of the flexible structure in relation to the rigid structure;

(c) said second gear coupled to a second linear coupling member; and

(d) said second linear coupling member configured for attachment to a damper.

62. A seismic isolator as recited in

claim 61

, wherein the coupling between the gears and the linear coupling members is provided by rack-pinion coupling.

63. A seismic isolator as recited in

claim 56

, wherein the means for mechanically amplifying movement is combined with said damper within a rotating damper assembly, comprising:

(a) a linear coupling member subject to the relative displacement of the gravity frame in relation to the reaction frame;

(b) a gear-driven propeller coupled to said linear coupling member and configured to amplify the linear displacement of the linear coupling member into the rotational motion of said propeller; and

(c) a housing filled with viscous fluid surrounding said propeller.

64. A seismic isolator as recited in

claim 63

, wherein said coupling between said linear coupling member and said gear drive propeller is provided by a rack-pinion coupling.

65. A seismic isolator as recited in

claim 64

, wherein said linear coupling member is configured with multiple pinions for driving multiple gear-driven propellers.

66. A seismic isolator as recited in

claim 65

, wherein said multiple gear-driven propellers are configured for counter-rotation in close proximity to one another within said fluid filled housing.

67. A seismic isolator as recited in

claim 56

, wherein said damper dissipates energy to reduce the motion of the flexible structure.

68. A seismic isolator as recited in

claim 56

, wherein said damper comprises a hydraulic damper.

69. A seismic isolator as recited in

claim 56

, wherein said damper comprises a friction damper.

70. A seismic isolator as recited in

claim 56

, wherein said damper comprises a viscous elastic damper.

71. In a seismic isolator configured for attachment within the frame of a civil structure to direct lateral displacement into a damper mechanism, the improvement comprising:

an apparatus configured for mechanically amplifying the displacement of the civil structure and directing said amplified displacement into a damper assembly.

72. The improvement as recited in

claim 71

, wherein the mechanical displacement amplification apparatus comprises a pivoting lever having arms of unequal length.

73. The improvement as recited in

claim 71

, wherein the mechanical displacement amplification apparatus comprises:

(a) a pivoting lever;

(b) said pivoting lever having a short arm configured to receive a motion associated with the physical displacement of the civil structure; and

(c) said pivoting lever having a long arm, whose output amplifies the motion input to the short arm, coupled to the damper assembly.

74. The improvement as recited in

claim 71

, wherein the mechanical amplification apparatus comprises:

(a) a rotating gearset having gears of different diameters;

(b) a small diameter gear within said gearset coupled to a linear coupling member subject to the motion of the flexible structure in relation to rigid structure, and

(c) a large diameter gear within said gearset which amplifies the motion received by said first gear and couples to a linear coupling member which is received by said damper assembly to dissipate mechanical energy.

75. The improvement as recited in

claim 71

, wherein the coupling between the gears and the linear coupling members comprise rack and pinion mechanisms.

76. The improvement as recited in

claim 71

, wherein the mechanical amplification apparatus is combined with said damper assembly within a rotating damper assembly, comprising:

(a) a linear coupling member subject to the movement of the civil structure;

(b) a gear-driven propeller coupled to said linear coupling member and configured to amplify the displacement of the linear coupling member into the rotational motion of said propeller; and

(c) a housing filled with viscous fluid surrounding said propeller.

77. An apparatus for placement within the gravity frame of a structure which passively dissipates displacement energy upon the mechanical distortion of said gravity frame, comprising:

(a) a reaction frame rigidly coupled to a base level;

(b) a rotating damper coupled to a linear coupling member which is subject to linear motion as the gravity frame is distorted in relation to said reaction frame; and

(c) said rotating damper is configured with a propeller that rotates within a fluid filled housing.

78. An apparatus as recited in

claim 77

, wherein said coupling between said linear coupling member and said rotating damper is provided by a rack-pinion coupling.

79. An apparatus as recited in

claim 77

, wherein said rotating damper is configured to couple the motion of the linear coupling member to multiple propellers.

80. An apparatus as recited in

claim 79

, wherein said multiple propellers are configured for counter-rotation in close proximity to one another within said fluid filled housing.

81. A method of dissipating the energy associated inter story displacement within a civil structure, comprising:

registering the motion associated with said inter story displacement;

amplifying said motion; and

receiving said motion within damping assembly.

82. A method as recited in

claim 81

, wherein amplifying said motion comprises receiving the registered motion on the first arm of a pivoting lever, and outputting amplified motion on a longer second arm of said pivoting lever.

83. A method as recited in

claim 81

, wherein amplifying said motion comprises receiving the registered motion on a first gear within a rotating gearset, said first gear attached to a larger second gear coupled to a linear coupling member which is induced to move by an amplified amount.