Yielding Rod to Counter Seismic Activity

Abstract

A yielding rod to counteract seismic activity having a generally cylindrical shape with a narrow portion having a reduced cross-sectional diameter relative to the remaining portions of the yielding rod. The narrow portion spans a length that is approximately 8 times its diameter to approximately 16 times its diameter. A transition area connects the narrow portion of the rod to the remainder of the rod. The transition area spans a length of approximately 0.25 inch to approximately 1.5 inch and has a preferred slope of 30 degrees or less relative to a longitudinal axis of the rod.

1 . A yielding rod defining a longitudinal axis, comprising:
 a. a first portion terminating at a first end having a first cross-sectional diameter;   b. a second portion opposite the first portion, the second portion terminating at a second end and having a second cross-sectional diameter;   c. a narrow portion in between the first and second portions, the narrow portion have a third cross-sectional diameter and a length;   d. a first transition area in between and connecting the first portion and the narrow portion; and   e. a second transition area in between and connecting the second portion and the narrow portion,   f. wherein the third cross-sectional diameter is smaller than the first and second cross-sectional diameters,   g. wherein the first transition area and the second transition area each have a taper that gradually narrows towards the narrow portion, and   h. wherein the length of the narrow portion is greater than the third cross-sectional diameter,   i. wherein the first and second transition areas each have a transition length of approximately 0.25 inch to approximately 2 inches,   j. wherein the first and second transition areas each have a slope relative to the longitudinal axis greater than zero degrees and less than approximately 90 degrees,   k. wherein the length of the narrow portion is at least approximately 8 times the diameter of the third cross-sectional diameter, and   l. wherein the narrow portion has a static strength in tension that is less than a static concrete breakout strength in tension and a static pullout strength in tension of a concrete foundation in which the yielding rod is embedded.   
     
     
         2 . The rod of  claim 1 , wherein the first and second transition areas each have a transition length of approximately 0.5 inch to approximately 1.5 inch. 
     
     
         3 . The rod of  claim 1 , wherein the first and second transition areas have a slope relative to the longitudinal axis of approximately 30 degrees or less. 
     
     
         4 . The rod of  claim 2 , wherein the length of the narrowed portion is between about 8 times and about 16 times the diameter of the third cross-sectional diameter. 
     
     
         5 . A rod defining a longitudinal axis, comprising:
 a. a first portion terminating at a first end having a first cross-sectional diameter;   b. a second portion opposite the first portion, the second portion terminating at a second end and having a second cross-sectional diameter;   c. a narrow portion in between the first and second portions, the narrow portion have a third cross-sectional diameter and a length;   d. a transition area in between and connecting the first portion and the narrow portion,   e. wherein the third cross-sectional diameter is smaller than the first and second cross-sectional diameters,   f. wherein the transition area has a taper that gradually narrows towards the narrow portion, and   g. wherein the length of the narrow portion is greater than the third cross-sectional diameter.   
     
     
         6 . The rod of  claim 5 , wherein the transition area has a transition length of approximately 0.25 inch to approximately 2 inches, 
     
     
         7 . The rod of  claim 5 , wherein the transition area has a transition length of approximately 0.5 inch to approximately 1.5 inches. 
     
     
         8 . The rod of  claim 5 , wherein the transition area has a slope relative to the longitudinal axis greater than zero degrees and less than 90 degrees. 
     
     
         9 . The rod of  claim 5 , wherein the first and second transition areas have a slope relative to the longitudinal axis of approximately 30 degrees or less. 
     
     
         10 . The rod of  claim 5 , wherein the length of the narrow portion is at least approximately 8 times the diameter of the third cross-sectional diameter. 
     
     
         11 . The rod of  claim 5 , wherein the length of the narrow portion is between about 8 times and about 16 times the diameter of the third cross-sectional diameter. 
     
     
         12 . The rod of  claim 5 , wherein the narrow portion has a static strength in tension that is less than a static concrete breakout strength in tension and a static pullout strength in tension of a concrete foundation in which the yielding rod is embedded. 
     
     
         13 . A rod defining a longitudinal axis, comprising:
 a. a first portion having a first end and a second end, and a first cross-sectional diameter;   b. a narrow portion having a second cross-sectional diameter and a length;   c. a transition area operatively connecting the first portion to the second portion, the transition area having a taper,   d. wherein the second cross-sectional diameter is smaller than the first cross-sectional diameters, and   e. wherein the taper of the transition area gradually narrows towards the narrow portion forming a slope of approximately 30 degrees or less relative to the longitudinal axis.   
     
     
         14 . The rod of  claim 13 , wherein the transition area has a transition length of approximately 0.25 inch to approximately 2 inches, 
     
     
         15 . The rod of  claim 13 , wherein the transition area has a transition length of approximately 0.5 inch to approximately 1.5 inches. 
     
     
         16 . The rod of  claim 13 , wherein the length of the narrow portion is at least approximately 8 times the diameter of the second cross-sectional diameter. 
     
     
         17 . The rod of  claim 13 , wherein the length of the narrow portion is between about 8 times and about 16 times the diameter of the second cross-sectional diameter. 
     
     
         18 . The rod of  claim 13 , wherein the narrow portion has a static strength in tension that is less than a static concrete breakout strength in tension and a static pullout strength in tension of a concrete foundation in which the yielding rod is embedded.