Innovative technique to construct a robust durable seismic protective device

Abstract

The invention is an innovative technique to construct a robust durable protection device for structures against dynamic loadings such as earthquakes, wind, or mechanical vibrations. The technique utilizes friction between a sliding material such as PTFE and Cementitious Material (CM) (not metal) to protect structures. The invention controls the surface roughness of the CM by employing a designed mix with small size to no aggregates and cast it in molds with different roughness to produce a friction coefficient ranging from 0.3% to 40%. The CM mix preferably has a ultimate strength higher than 3,000 psi. The CM includes, but is not limited to, polymer concrete, high performance concrete, geopolymer and ultra-high-performance concrete. The resulting sliding material and the specially molded CM can be used in several forms to protect structures against dynamic loading such as dampers or base isolators.

I claim: 
     
         1 . A seismic protection device comprising:
 a pad made of Cementitious Material (CM);   a sliding puck supporting a protected structure; and   a slider made of sliding material between the sliding puck and the pad.   
     
     
         2 . A seismic protection device of  claim 1 , wherein the CM is polymer concrete. 
     
     
         3 . A seismic protection device of  claim 1 , wherein the CM is a high performance concrete. 
     
     
         4 . A seismic protection device of  claim 1 , wherein the CM is geopolymer and ultra-high-performance concrete. 
     
     
         5 . A seismic protection device of  claim 1 , wherein the coefficient of friction between the pad and the slider ranges from 0.3% to 40%. 
     
     
         6 . A seismic protection device of  claim 1 , wherein the pad has an ultimate strength higher than 3,000 psi. 
     
     
         7 . A seismic protection device of  claim 1 , wherein the slider is made of Polytetrafluoroethylene (PTFE). 
     
     
         8 . A seismic protection device of  claim 1 , wherein the slider is made of Ultra-High Molecular Weight Polyethylene (UHMWPE). 
     
     
         9 . A method of constructing a seismic protection device, the method comprising the steps of:
 preparing a mix of cementitious material (CM) to produce a desired surface roughness;   casting a pad using the CM mix;   positioning a sliding puck supporting a protected structure on the pad; and   a sliding material attached to the sliding puck resides between the sliding puck and the pad.   
     
     
         10 . A method of constructing a seismic protection device of  claim 9 , wherein the CM mix is comprised of small size aggregate to no aggregate. 
     
     
         11 . A method of constructing a seismic protection device of  claim 9 , wherein the CM mix is cast in molds with varying roughness to provide coefficient of friction from 0.3% to 40% between the pad and sliding puck. 
     
     
         12 . A method of constructing a seismic protection device of  claim 9 , wherein the CM mix is comprised of polymer concrete. 
     
     
         13 . A method of constructing a seismic protection device of  claim 9 , wherein the CM mix is comprised of high performance concrete. 
     
     
         14 . A method of constructing a seismic protection device of  claim 9 , wherein the CM mix is comprised of geopolymer and ultra-high-performance concrete. 
     
     
         15 . A method of constructing a seismic protection device of  claim 9 , wherein the CM mix is designed to have an ultimate strength higher than 3,000 psi. 
     
     
         16 . A method of constructing a seismic protection device of  claim 9 , wherein the pad surface has a range of coefficient of friction from 0.3% to 40%. 
     
     
         17 . A method of constructing a seismic protection device of  claim 9 , wherein the sliding material is made of Polytetrafluoroethylene (PTFE). 
     
     
         18 . A method of constructing a seismic protection device of  claim 9 , wherein the sliding material is made of Ultra-High Molecular Weight Polyethylene (UHMWPE). 
     
     
         19 . A method of constructing a seismic protection device, the method comprising the steps of:
 preparing a mix of cementitious material (CM) to produce a desired surface roughness;   casting a pad using the CM mix; and   positioning a slider fixed to a sliding puck against the pad within a seismic damper system.   
     
     
         20 . A method of constructing a seismic protection device of  claim 19 , wherein:
 the CM is either polymer concrete, high performance concrete, geopolymer, or ultra-high-performance concrete;   the CM has a coefficient of friction ranges from 0.3% to 40%; and   the pad has an ultimate strength higher than 3,000 psi.