Abstract:
A system and method of stabilizing wall structures constructed with hollow core cementitious blocks that have not been filled with concrete. Relatively small cores are drilled along either the upper or lower portion of the wall structure to allow for the insertion of a rigid yet flexible reinforcing rod into the hollow core of the block. Through the same hole and other ports drilled into the hollow core block, high density expanding resin is injected to fully fill and encapsulate the reinforcing bar or rod thereby providing sufficient rigidity to the wall structure to withstand significant seismic activity.

Description:
BACKGROUND 
       [0001]    This patent document relates to a system to reinforce cindercrete or other cementitious hollow core building blocks used in the construction of walls, building and other enclosures or enclosed spaces. 
         [0002]    Many wall structures, typically no more than three stories in height, are constructed of cementitious hollow core blocks. Wall structures for schools, industrial and commercial buildings, warehouses, and other structures are commonly constructed from such building material. The hollow cores are filled with concrete, a loose insulation or are left hollow. 
         [0003]    Concern has arisen in regard to the stability of structures constructed with hollow core blocks located in earth quake prone zones. Since the hollow core blocks are held together with only a cementitious grout, there is concern that seismic activity and the tremors such activity can create will collapse such rigid cementitious structures. 
         [0004]    Stabilizing existing hollow core block wall structures using cementitious materials such as concrete requires much work, which is very intrusive and dirty, and typically requires considerable block break-out to allow for the pouring of concrete into the hollow cores to provide additional rigidity to the wall structure. Any concrete fill into the cavity of a hollow core block will add significant weight to the structure&#39;s foundation which was probably not designed for such additional loading. Typically as well, a steel reinforcing bar would be inserted into the hollow cores which requires further break out of the structure at the top of the wall to access the hollow cores to allow for the insertion of the reinforcing bar. 
       SUMMARY 
       [0005]    This patent document addresses these and other difficulties with the prior art. 
         [0006]    There is provided a method of stabilizing structures constructed with hollow core blocks. A reinforcing rod is inserted into the hollow core block and expanding polymer resin is injected into the hollow core block. 
         [0007]    These and other aspects of the device and method are set out in the claims, which are incorporated here by reference. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0008]    Embodiments will now be described with reference to the figures, in which like reference characters denote like elements, by way of example, and in which: 
           [0009]      FIG. 1  is a cross section of a hollow core block. 
           [0010]      FIG. 2  is side view of a wall configuration of hollow core blocks; 
           [0011]      FIG. 3  is a cross section of a hollow core block filled with expanding polymer resin; 
           [0012]      FIG. 4  is a side view of a wall configuration with ports for supplying reinforcing material and polymer resin into the wall; and 
           [0013]      FIG. 5  shows a perspective view of three hollow core blocks in the wall configuration of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    In the claims, the word “comprising” is used in its inclusive sense and does not exclude other elements being present. The indefinite article “a” before a claim feature does not exclude more than one of the feature being present. Each one of the individual features described here may be used in one or more embodiments and is not, by virtue only of being described here, to be construed as essential to all embodiments as defined by the claims. 
         [0015]      FIG. 1  shows a hollow core block  10 . The hollow core block  10  is made of a cementitious shell  14 , which surrounds a hollow core  12 .  FIG. 2  shows a wall configuration using hollow core blocks  10 . A foundation  16  supports the hollow core blocks  10 . Grout lines going horizontally and vertically around each hollow core block  10  are filled with mortar  18 . 
         [0016]      FIG. 3  shows a cross section of a treated hollow core block  10 . Expanding polymer resin  20  fills the hollow core  12  of the hollow core block  10 . Reinforcing rods  22  are placed within the hollow core  12 . The reinforcing rods  22  are held in place by the expanding polymer resin  20 . 
         [0017]      FIGS. 4 and 5  show a wall structure constructed from hollow core blocks  10 .  FIG. 4  shows ports  24  and  26  through the cementitious shells  14  ( FIG. 1 ) of the hollow core blocks  10 . Ports  24  may be larger in size than ports  26  to allow the reinforcing rods  22  to be threaded through ports  26  into the hollow core  12  ( FIG. 1 ) of the hollow core block  10 . Polymer resin may be injected through the smaller ports  26 . Each port may be used to supply reinforcing rods  22  into the hollow core  12  or each port may be used to supply expanding polymer resin into the hollow core  12 , or each port may be used to supply both reinforcing rods  22  and supplying expanding polymer resin into the hollow core  12 . Although ports  24  and  26  are shown in different sizes in  FIG. 4 , all the ports may be constructed with uniform size. The ports may also be existing holes in the hollow core block from previous construction work. Additionally, the ports may be created perpendicularly into the side of the blocks, or may be cut at an angle to assist in introducing the reinforcing rods. 
         [0018]    As shown in  FIG. 5 , the hollow core blocks  10  may be stacked so that the hollow cores  12  define a hollow channel into which the reinforcing rods  22  and expanding polymer resin can be supplied. Depending on the height of the hollow channels, multiple ports may be provided in each of the hollow channels to provide multiple insertion points for the reinforcing rods and the expanding polymer resin. The ports may also be created at the top of the wall structure. Access to the hollow channels may also be provided directly through the top of the wall structure by removing or partially removing the roof of the structure. The reinforcing rods  22  and expanding polymer resin may be introduced directly into the hollow channels through the top of the wall if the wall has no roof or if the roof has been partially removed. Inserting the reinforcing rods through the top of the wall structure may provide an easier method of introduction long lengths of reinforcing rods into the hollow channels. 
         [0019]    The expanding polymer resin may be delivered into the hollow cores of existing cementitious block wall structures by firstly inserting a reinforcing material through a relatively small cored hole in the hollow core block and then filling the hollow core with the expanding polymer resin through ports which may be no larger than ⅝″ in diameter. 
         [0020]    Depending upon the height of the wall structure, two or more injection ports may have to be drilled to access the hollow channel of a stack of hollow core blocks  10 . The high density expanding resin is then injected into the hollow core and the aggressive expansive nature of the resin will fill the cores and encapsulate the reinforcing material thereby providing significantly increased rigidity to the wall structure in case of seismic activity. 
         [0021]    The reinforcing rods  22  may be any structural support which reinforces the hollow channels when the hollow channels are filled with expanding polymer resin. The reinforcing rods may be a solid or hollow core synthetic polymer rod, tube, bar, coil or pipe or may be a metallic rod, bar, tube, coil or pipe. Other materials and designs may be used to provide equivalent structural support. 
         [0022]    Reinforcing rods and expanding polymer resin provide an effective method of stabilizing wall structures constructed of hollow core block. There are additional benefits as a consequence of using reinforced rods and expanding polymer resin. The extremely lightweight nature of the expanding polymer resins does not add significant weight to an existing foundation that may not be designed for additional weight loading. The very high R-value of the expanding resin will provide additional thermal protection to the structure. Additionally, polyurethane foam is an excellent sound inhibitor and as such will provide increased sound insulation to treated walls. 
         [0023]    Expanding polymer resin, being flexible and not brittle, will not break under conditions where hollow or cement filled cementitious blocks will break. For example, in an earthquake, blocks may knock against each other and break, rather than swaying from side to side. Blocks having hollow channels that are filled with expanding polymer resin will sway together as a cohesive structure rather than crumbling into each other. 
         [0024]    The cementitious blocks in this patent application may be any type of hollow core block, for example including cement, concrete or cindercrete blocks. 
         [0025]    The ports created in the hollow shells may be created by drilling, chiseling, chopping, coring, punching, hammering or any other method. Many different types of expanding polymer resin may be used to fill the hollow channels. One example of expanding polymer resin is high density closed cell expanding polyurethane foam. Any method of injecting the expanding polymer resin may be used. 
         [0026]    When injecting expanding polymer resin into the hollow channels in a wall, expanding polymer resin may be introduced into every hollow channel. However, expanding polymer resin may not need to be introduced into every hollow channel. For example, the expanding polymer resin may be inserted into every second hollow channel to provide the necessary additional support for the wall. The number and spacing of the reinforcing rods may depend on the height of the wall. Flexible reinforcing rods may be introduced to allow insertion into the side of a wall of hollow core blocks. Reinforcing rods introduced through the top of a wall of hollow core blocks need not be flexible. The size of reinforcing rod able to be introduced into the wall will be dependant on the size of the ports created. 
         [0027]    Immaterial modifications may be made to the embodiments described here without departing from what is covered by the claims.