Load-limiting device

Abstract

A load-limiting device for using in a braced frame structure is provided. The load-limiting device may be placed in a braced frame and connected to the braces of the braced frame. The load-limiting device is able to limit the lateral loads induced in the structure during a dynamic event by plastic and ductile deformation. The load-limiting device, by limiting the dynamic loads in the braced frame, may protect other less ductile areas of the structure from the loads that might lead to extensive damage, member failure and/or structural collapse. The load-limiting device is positioned within a braced frame structure and may be easily removed after it has undergone plastic deformation and replaced with an undeformed load-limiting device. The load-limiting device exhibits elastic strength to survive, without deformation, minor load scenarios. The device is suitable for retrofitting in existing structures that are susceptible to dynamic activity and that have inadequate dynamic loading capacity.

1 . A load-limiting device for use in a braced frame, comprising: 
 a braced frame structure having at least one beam rigidly interconnected to a first column and a second column;    a load-limiting device releasably attached to a brace wherein said brace is attached to said braced frame structure;    a connection means releasably attached to said load-limiting device; and    said load-limiting device providing biaxial support for the braced frame wherein said load-limiting device is able to dissipate energy in the braced frame structure.    
   
   
       2 . The load-limiting device as described in  claim 1 , further comprising: 
 said load-limiting device being able to plastically deform in response to a load applied thereto.    
   
   
       3 . The load-limiting device as described in  claim 1 , further comprising: 
 said load-limiting device plastically deforming in response to load wherein said load-limiting device has elasto-plastic properties to allow for formation of a plastic hinge mechanism.    
   
   
       4 . The load limiting device as described in  claim 1 , further comprising: 
 said load limiting device which can withstand small loads without plastic deformation based on its elasto-plastic properties.    
   
   
       5 . The load-limiting device described in  claim 1  wherein said load-limiting device is constructed of a plastic material.  
   
   
       6 . The load-limiting device described in  claim 1  wherein said load-limiting device is constructed of a metal based elasto-plastic material.  
   
   
       7 . The load-limiting device as described in  claim 1 , further comprising: 
 said load-limiting device attaching to said connection means wherein said connection means couples the load-limiting device and the brace in the braced frame structure.    
   
   
       8 . The load-limiting device as described in  claim 1 , further comprising: 
 said load-limiting device having an opening thereon for attachment of the connection means to the brace.    
   
   
       9 . The load-limiting device as described in  claim 1 , further comprising: 
 said load-limiting device having a plurality of connection points wherein said connection points are releasably attached to said connection means.    
   
   
       10 . A dynamic load, load-limiting device for braced frames comprising: 
 a braced frame structure having at least one beam rigidly connected to a first column and a second column;    said brace frame structure having at least one brace;    a load-limiting device releasably attached to said brace wherein said brace attaches to said at least one beam;    a connection means detachably coupled to said at least one brace and said load-limiting device; and    said load-limiting device in connection with said brace and said braced frame structure to dissipate energy when high lateral loads are placed on the braced frame structure.    
   
   
       11 . The dynamic load, load-limiting device as described in  claim 10  further comprising: 
 said load-limiting device undergoing plastic deformation when subjected to high lateral loads.    
   
   
       12 . The dynamic load, load-limiting device described in  claim 10  wherein said load limiting device is releasably attached to said brace wherein said brace is attached to said at least one beam.  
   
   
       13 . The dynamic load, load limiting device described in  claim 10  wherein said load limiting device is releasably attached to said brace wherein said brace is attached to said two columns.  
   
   
       14 . The dynamic load, load-limiting device described in  claim 10  wherein said load-limiting device when subjected to a dynamic event yields to form a hinged mechanism to dissipate energy in the braced frame structure during a dynamic event.  
   
   
       15 . The dynamic load, load-limiting device described in  claim 10  wherein said load-limiting device may be removed from the braced frame structure after a dynamic event wherein the load-limiting device has undergone plastic deformation and further wherein a new un-deformed load-limiting device may be inserted into the braced frame structure to replace a plastically deformed load-limiting device.  
   
   
       16 . A method for using a load-limiting device system, said method comprising the steps of: 
 providing braced frame having at least one beam and two side columns;    integrating at least one brace into the braced frame;    integrating a load-limiting device into the system; and    providing a connection means to connect the load-limiting device to the braced frame wherein a connection means is releasably attached to said load-limiting device and said brace.    
   
   
       17 . The method of  claim 16 , further comprising the step of: 
 placing the load-limiting device into an existing braced frame with a connection means.    
   
   
       18 . The method of  claim 16 , further comprising the step of: 
 providing the device with an indicator means wherein said indicator means allows for assessment of plastic deformation of the load limiting device.    
   
   
       19 . The method of  claim 16 , further comprising the step of: 
 periodically checking said load-limiting device for the existence of plastic deformation after dynamic activity.    
   
   
       20 . The method of  claim 16 , further comprising the step of: 
 removing a plastically deformed load-limiting device from a braced frame after a dynamic event.    
   
   
       21 . The method of  claim 16 , further comprising the step of: 
 replacing a plastically deformed load-limiting device from a braced frame with an un-deformed load-limiting device after a dynamic event.