Patent EA-002391-B1 (EA)
Title: Earthquake protection consisting of vibration-isolated mounting of buildings and objects using vertical pendulums with long cycles
Inventor: BIERWIRTH FRIEDHELM
IPC: E04H9/02
Filed: 1998-08-13
Abstract: 1. Method for protecting objects, particularly buildings, against dynamic forces from accelerations of the base (6), e.g. caused by earthquakes, characterized in that the object is constructed on a coupling element (8,9) connected, at least, with one stable supporting element (3,11), which is able to raise the supported object, and, at least, with one unstable supporting elements (7,14), which is able to lower the supported object thus providing for a support point (P) of the supported object positioned on the coupling element (8,9) to move by a trajectory coinciding with a trajectory of a pendilum having the length longer than the length of the supporting element. 2. A device for realizing the method according to claim 1, characterized in that in at least three supporting points relative to the base (6) for isolating against oscillations of the support point (P) of the object (1) said device comprises the coupling element (8,9,14), on which the support point (P) of the object (1) is positioned, said coupling elements which are able to swing in any direction via supporting elements (3,7,11,14) which are coupled together and hingely mounted on the base (6), wherein the dimensioning and positioning of the supporting elements (3,7,11,14) are chosen in such a way that to provide for the supporting point (P) to move by a trajectory coinciding with a trajectory of a pendilum having the length longer than the length of the supporting element. 3. The device according to claim 2, characterized in that the coupling element (8,9) is lifted at one side where it is linked to the supporting elements (3,7,11) and is lowered at the opposite side, and that the support point (P) an the coupling element (8, 9, 14) supporting the object (1) experiences only a minimal lift and moves along a flatly curved concave locus. 4. The device according to claims 2 or 3, characterized in that there are two supporting elements (2,7) bi-axially hinged to one coupling element (8,8b), where one of the two supporting elements (2) is realized as a hanging stable pendulum, that at its upper end is bi-axially hinged to a supporting point (10), which is rigidly connected to the base (6), end where the other of the two supporting elements (7) is realized as a standing unstable pendulum, flat is bi-axially hinged at its lower end to the base (6), and where the coupling element (8,8b) is connected to the supported object (1) by the means of two bearings, creating a horizontal axis, so that, relative to the object (1), the coupling element (8,8b) is prevented to rotate around its vertical axis. 5. The device according to claim 4, characterized in that the coupling element (8) is articulated into an additional coupling element (8b), connected by a vertical coupling element (8a), one-axially hinged at its ends to both coupling elements (8,8b), and that the coupling element (8b) is one-axially hinged to the load support (WL) at one end and at its ether end is supported by the top of this unstable pendulum, supporting element (7), bi-axially jointed. 6. The device according to claims 2 or 3, characterized in that three supporting elements (11) are bi-axially hinged to three points along the perimeter of the coupling element (9), each in their resting position pointing upwards and inclined away from the center of the coupling element (9), and are each bi-axially hinged to suspension points, which are rigidly connected to the base(6). 7. The device according to claim 6, characterized in that the support point (P) for the object (1) is positioned above, the plane formed by the three bearing points (12) that join the supporting elements (11) with the coupling element (9). 8. The device according to claim 2, characterized in that the coupling element (8) bi-axially joined with the lower ends of at least two parallel supporting elements (3), which at their upper ends are bi-axially joined with support points (10) that are rigidly connected with the base (6), supports in a one-axial bearing in its middle a support element (14), which tilts only in the direction of the support points, that connect the coupling element (8) and the supporting elements (3), and which below its bearing in the coupling element (8) is positioned in a bi-axial bearing with axial movability, and which above its bearing in the coupling element (8) supports the object (1) in a bi-axially movable support point (P). 9. The device according to claim 2, characterized in that the coupling element (8) is supported by several symetrically positioned parallel supporting elements (3), and the supporting element (14) is supported in the coupling element (8) in a bi-axial bearing. 10. The device according to claims 2 to 9, characterized in that for the purpose of wind load compensation, a shaft (42) is positioned beneath the supported object (1) between the base (6) and the object (1) to restrain lateral forces, whereby one end of the shaft (42) is rigidly connected to one end of a preloaded extension spring (41), which other end is rigidly connected either to the base (6) or the supported object (1), and whereby the other end of the shaft (42) sticks axially movable into a bi-axially movable spherical bearing (43) that is connected either to the supported object (1) or to the base (6), and through which the position of the object (1) is fixed towards the base (6), and a relative movability of the object (1) and the base (6) towards each other becomes only possible if a lateral force impacts the shaft that exceeds the tension force of the preloaded extension spring (41). 11. The device according to claims 2 to 9, characterized in that underneath the supported object (1) between the base (6) and the objet (1) is positioned a shaft (42) to retain lateral forces, whereby one end of the shaft (42) is rigidly connected to an elastomeric spring block (48), that is rigidly connected either to the base (6) or to the supported object (1), and whereby the other end of the shaft sticks axially movable into a biaxially movable spherical bearing (43), which is connected either to the supported object (1) or to the base (6), through which the position of object (1) and base (6) towards each ether is elastically fixed. 12. The device according to claims 2 to 9, characterized in that for the purpose of the compensation of wind loads underneath the supported object (1) one or several wind load compensation devices (50) are installed, whereby for each device a vertically guided sphere (44), that can turn in all directions, is pressed with a predetermined force by a mechanical or hydropneumatic spring (47) downwards into the center of a to the base (6) rigidly connected hollow cone (45), which has a particular opening angle that increases from its center to 180 degree  degrees, through which a shape locked connection between the object (1) and the base (6) comes about, that can transfer horizontal forces up to a limit value, determined by the spring force and the opening angle in the center of the hollow cone (45), when the limit value is exceeded by the horizontal force, the incline of the hollow cone (45) lifts the sphere (44) vertically against the spring force, and the sphere (44) rolls into the area of the lessening incline of the hollow cone (45), through which the horizontally transferable force decreases and becomes zero outside the area of the hollow cone (45), end therefore, during relative movements, of the base (6) towards the object (1) caused by earthquakes, only little or, depending on the amplitude of oscillations, virtually zero horizontal forces are transferred from the base (6) onto the object (1). 13. The device according to claim 12, characterized in that to center a because of the kind of its bearing easily horizontally movable object or building and to provide a retaining force, a vertically guided centering sphere (44), held in a dish with rolling balls (49) is pushed by a mechanical or hydropneumatic or visco elastic spring into a centering hollow cone (45), so that no horizontal wind force impacting the building structure (51) cook cause a reaction force at the connecting point of the centering ball (44) with the hollow cone (45), whose vertical component (FV) would push the centering ball (44) up in its vertical guidance against the spring force. 14. The device according to claim 12, characterized in that a centering hollow cone (45), outside of the circle that is formed by the contact line of the centering sphere (44) with the hollow cone in its lowest position within, has an up to 180 degree  increasing opening angle (.gamma.) so that the horizontal component (FH) of the normal force in the contact point of the centering sphere (44) with the centering cone (45) decreases radially outward, if a lateral displacement force greater than maximum horizontal wind loads compresses the vertical spring in its vertical guidance through the centering sphere (44), and the contact point of the centering sphere (44) and the centering cone (48) moves radially outward in the centering cone (45). 15. The device according to claim 12, characterized in that the centering sphere (44) in its vertical guidance can move undampened, if a vertical force (FV), caused by a horizontal displacement of the centering hollow cone (45), exceeds the spring force, end that a pushing back of the vertical guidance with the centering sphere (44) by the spring is slowed to a very low speed by a hydraulic throttling, so that the time period for the full spring return is a multiple of a maximum earthquake oscillation time period. 16. The device according to claims 2 to 9, characterized in that for the purpose of compensation of wind loads. between the vertical walls of the base (6) and the supported object (1) there are at least 3 pairs of mechanical or hydropneumatic springs (47) with a low spring rate mirror-image wise positioned around the supported object (1), with one pair for each axis of movement, one pair for the vertical axi