Asymmetric damping system for, and method of, protecting structures subjected to external dynamic forces

Abstract

A structure having at least one generally horizontal flexural member extending between a pair of spaced-apart, upright columns, is protected from seismic forces by connecting one end of an elongated damping member to a first structural node on one of the columns, and by connecting an opposite end to a nodal junction on the flexural member. An undamped, rigid body is connected to the nodal junction and to a second structural node on the other of the columns. In response to the seismic forces, the rigid body is turned about the second structural node, the flexural member is flexed, an amplified force is exerted, and the damping member is displaced along an amplified working stroke.

I claim: 
     
         1 . An asymmetric damping system for protecting a structure when subjected to external dynamic forces, the structure having at least one generally horizontal flexural member extending between a pair of spaced-apart, upright columns, the system comprising:
 an elongated damping member having one end operatively connected to a first structural node on one of the columns and an opposite end operatively connected to a nodal junction on the flexural member, the damping member extending from the first structural node to the nodal junction along a first inclined direction, the damping member having a damping element that is displaceable along the first inclined direction; and   an undamped, rigid body operatively connected to the nodal junction and operatively connected to a second structural node on the other of the columns, the rigid body being turnable about the second structural node in response to the external dynamic forces for flexing the flexural member, for exerting an amplified force, and for displacing the damping element along an amplified working stroke along the first inclined direction to protect the structure from the external dynamic forces.   
     
     
         2 . The system according to  claim 1 , wherein the rigid body has three sides and includes an elongated stiffening brace as one of its sides, the brace having one end operatively connected to the nodal junction and an opposite end operatively connected to the second structural node, the brace extending from the second structural node to the nodal junction along a second inclined direction that is different from the first inclined direction. 
     
     
         3 . The system according to  claim 1 , wherein the rigid body includes one of a shear wall and a truss. 
     
     
         4 . The system according to  claim 1 , wherein the nodal junction on the flexural member is a common pivot point pivotably connected to both the damping member and the rigid body. 
     
     
         5 . The system according to  claim 1 , wherein the damping member and the rigid body generally lie in a common plane. 
     
     
         6 . The system according to  claim 1 , wherein the damping member and the rigid body generally lie in different planes that intersect one another. 
     
     
         7 . An asymmetric damping system for protecting a multi-floor building when subjected to external dynamic forces, the building having a pair of spaced-apart, upright columns and a plurality of generally horizontal flexural members in mutual parallelism, each flexural member extending on each floor between the columns, the system comprising:
 at least one elongated damping member having one end operatively connected to a first structural node on one of the columns and an opposite end operatively connected to a nodal junction on at least one of the flexural members, the at least one damping member extending from the first structural node to the nodal junction along a first inclined direction, the at least one damping member having a damping element that is displaceable along the first inclined direction; and   at least one undamped, rigid body operatively connected to the nodal junction and operatively connected to a second structural node on the other of the columns, the at least one rigid body being turnable about the second structural node in response to the external dynamic forces for flexing the at least one flexural member, for exerting an amplified force, and for displacing the at least one damping element along an amplified working stroke along the first inclined direction to protect the building from the external dynamic forces.   
     
     
         8 . The system according to  claim 7 , further comprising additional elongated damping members, each additional damping member having one end operatively connected to additional first structural nodes on the one column and an opposite end operatively connected to additional nodal junctions on others of the flexural members, the additional damping members extending from the additional first structural nodes to the additional nodal junctions along additional inclined directions that are parallel to the first inclined direction, each additional damping member having an additional damping element. 
     
     
         9 . The system according to  claim 7 , further comprising additional rigid bodies including additional elongated stiffening braces, each having one end operatively connected to additional nodal junctions on others of the flexural members and an opposite end operatively connected to additional second structural nodes on the other column, the braces extending from the additional second structural nodes to the additional nodal junctions along additional second inclined directions that are parallel to the second inclined direction. 
     
     
         10 . The system according to  claim 7 , further comprising additional rigid bodies, each including one of a shear wall and a truss. 
     
     
         11 . The system according to  claim 7 , further comprising additional elongated damping members and additional rigid bodies, and wherein only selected ones of the floors contain the additional damping members and the additional rigid bodies. 
     
     
         12 . A method of protecting a multi-floor building when subjected to external dynamic forces, the building having a pair of spaced-apart, upright columns and a plurality of generally horizontal flexural members in mutual parallelism, each flexural member extending on each floor between the columns, the method comprising:
 operatively connecting one end of at least one elongated damping member to a first structural node on one of the columns;   operatively connecting an opposite end of the at least one elongated damping member to a nodal junction on at least one of the flexural members;   configuring the at least one damping member to extend from the first structural node to the nodal junction along a first inclined direction, and to have a damping element that is displaceable along the first inclined direction;   operatively connecting at least one undamped, rigid body to the nodal junction;   operatively connecting the at least one rigid body to a second structural node on the other of the columns; and   configuring the at least one rigid body to turn about the second structural node in response to the external dynamic forces for flexing the at least one flexural member, for exerting an amplified force, and for displacing the at least one damping element along an amplified working stroke along the first inclined direction to protect the building from the external dynamic forces.