Abstract:
Masonry walls of buildings supported on concrete foundations are strengthened against destructive wind and seismic forces by spaced elongated members inserted inside the hollow masonry walls. The spaced elongated members are secured to the continuous masonry bond beam and the foundation. Tension means at the top of the masonry wall make the elongated members taut creating a continuous tension load path from bond beam to the foundation.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    Not Applicable 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable 
       REFERENCE TO A MICROFICHE APPENDIX 
       [0003]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0004]    Masonry structures predominate in residential and light commercial construction. In order to provide protection from strong winds, tornadoes, hurricanes, and seismic activity, builders reinforce installed masonry walls by filling cells of the masonry wall with concrete and steel bars at selected locations. The number of the reinforced cells, the quantity of concrete and the number of bars used vary depending on the severity of the wind and the geometry of the structure. 
         [0005]    Masonry structures can also be strengthened during installation. Masonry units are laid over the reinforcing bars so that the bars are in the center of the cell within the masonry unit. Builders install additional reinforcing bars inside the voids and pour concrete around the bars. After building the wall, builders construct a masonry bond beam on top of the masonry wall to bond all of the walls together. 
         [0006]    However, this method for strengthening masonry walls suffers from various problems. When builders fill the cells of a masonry wall with steel bars and concrete, they do not tie or connect the wall with the concrete foundation or the masonry bond beam. As a result, the masonry wall tends to vibrate back and forth during strong seismic movements or strong winds. 
         [0007]    Additionally, filling the cells or voids of the masonry units, strengthens the masonry units around these cells, but does not strengthen the adjacent units. As a result, the masonry units are not strongly bonded together. Therefore the masonry wall tends to be vulnerable to strong winds or seismic forces. In particular, the wall is vulnerable at the masonry units, which are further from the reinforced cells. 
         [0008]    Another method of strengthening buildings against winds and seismic forces is disclosed in applicant&#39;s U.S. Pat. No. 6,014,843. Wood framed walls of buildings are strengthened by spaced lengths of vertical wire rope having enlarged bulbous portions swaged on each end. Other lengths of wire rope form a cross brace connecting each story of a building with its foundation. The cross brace wire ropes terminate in bulbous portions connected to attachments therein. However, the method and system described above are applicable only to wood framed walls. 
         [0009]    Consequently, in light of the previous problems, there is a critical need for a structural tie-down system that provides for uplift, shear, and overturning loads that is cost efficient and installed after the foundation is laid and the masonry units have been placed. The present invention meets and exceeds these needs. 
         [0010]    It is an object of this invention to provide for a device for tensioning a masonry wall. 
         [0011]    It is another object of the present invention to provide a device for placing the masonry walls under compression to prevent them from vibrating or moving during strong winds or some seismic movement. 
         [0012]    It is still another object of the present invention to provide a device for tying a masonry bond beam on top of masonry walls with the concrete foundation that support these walls. 
         [0013]    It is a further object of the present invention to provide for a method for placing masonry walls under compression after building these walls. 
         [0014]    Yet another object of the present invention is to provide a method for installing a tensioning device in a hollow masonry wall to compress it. 
       BRIEF SUMMARY OF THE INVENTION 
       [0015]    The present invention relates to a novel device for placing masonry structures under compression and a method for installing the device in the masonry structure. The tie-down system can be installed after the foundation and masonry walls are completed or before installing the walls. The tie-down system creates a continuous tension path from the masonry bond beam on the top of the masonry wall to the foundation at the bottom. An elongated member, preferably in the form of a wire rope, is used for developing tension in a hollow masonry wall. The elongated member has a length greater than a length of the masonry wall to be tensioned. The elongated member includes lower and upper end portions. 
         [0016]    A method for installing the elongated member into the masonry structure after building the masonry walls includes the steps of removing knock-out portions of the hollow masonry units located adjacent the bottom of the masonry wall and exposing a surface portion of the foundation below the masonry wall and drilling an elongated bore into the exposed surface portion of the foundation. Providing a passageway through the bond beam by either drilling a bore therein or drilling a bore and placing a sleeve inside the bore and placing an adhesive inside the foundation bore. The elongated member is vertically inserted inside the hollow masonry units of the wall through the passageway to secure the lower end portion of the elongated member inside the foundation bore. After the adhesive is cured, a washer and nut are placed over the threaded upper end of the elongated member that extends through the passageway beyond the bond beam. The nut is tightened to tension the elongated member and place the masonry wall under compression. 
         [0017]    The elongated member can also be installed during the building of the masonry structure. A bore is drilled into a concrete foundation, and an adhesive is placed inside the bore. A first row of hollow masonry units is laid on the foundation. A second row of the masonry units is laid on the first row and vertically aligned to alternate holes of the vertically adjacent masonry units to create a continuous passageway with the bore in the foundation. A second row of the masonry units is laid on the first row and vertically aligned to alternate holes of the vertically adjacent masonry units to create a continuous passageway with the bore in the foundation. The elongated member is then inserted into the bore through the hollow masonry unit. Additional rows of the units are laid until the desired wall height is achieved. The bond beam is poured on top of the wall with a sleeve disposed around the upper end portion of the elongated member to keep concrete away from the passageway of the elongated member. A washer and a nut are threadedly engaged with the upper end portion of the elongated, member and tightened to tension the elongated member. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0018]    The novel features which are believed to be characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in connection with the accompanying drawings, in which: 
           [0019]      FIG. 1  is a front elevational view of a one-story masonry building structure showing the spaced elongated tension members according to the present invention for tensioning the masonry wall; 
           [0020]      FIG. 2  is a cross-sectional view showing the lower portion of the member of  FIG. 1  installed in a masonry building; 
           [0021]      FIG. 3  is an enlarged cross-section of the upper end portion of one embodiment of the tension member placed inside a passageway in the bond beam; 
           [0022]      FIG. 4  shows another embodiment of the upper portion of the invention; 
           [0023]      FIG. 5  shows a further embodiment of the upper portion of the invention; 
           [0024]      FIG. 6  shows another embodiment of the upper portion of the invention; 
           [0025]      FIG. 7  illustrates an upper plate employed in  FIG. 6 ; 
           [0026]      FIG. 8  illustrates a two-story application of the present invention; 
           [0027]      FIG. 9  illustrates another embodiment of the upper portion of the invention; and 
           [0028]      FIG. 10  illustrates a combined nut and sleeve employed in  FIG. 8 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0029]    The present invention may be best understood by reference to the attached drawings wherein  FIG. 1  shows the usage of the invention, and the remaining FIGS. Illustrate various embodiments of the tension device. 
         [0030]    In  FIG. 1  a partial section of a masonry building is shown at numeral  10 . The building includes at least two masonry walls  12  supported on a concrete foundation  13 . A continuous bond beam  11  is laid on top of the masonry walls  12  to strengthen the walls. Each of the masonry walls  12  includes a plurality of vertical hollow wall sections  14  having a number of hollow masonry units  15 , laid over each other. 
         [0031]      FIG. 1  shows a tensioning device, an elongated member  18 , installed in a hollow masonry wall  12 . The member  18  extends through and above the bond beam  11  located at the top of the masonry wall  12  and is secured to a foundation  13 , by securing means such as epoxy resin adhesive. The member  18  ties the masonry wall  12  with the bond beam  11  and the concrete foundation  13  to compress the masonry wall  12  between the bond beam  11  and the foundation to prevent the wall  12  from vibrating or moving during strong winds or seismic movement. 
         [0032]    A member  18  is disposed inside each vertical hollow wall section  14 , which includes a plurality of hollow masonry units  15  laid on top of each other forming a continuous vertical hole  32  throughout the vertical wall section  14 . In order to connected the masonry wall  12  with the bond beam  11  and the foundation  13 , the upper end portion  20  of the elongated member  18  is secured to the bond beam  11 , while the lower end portion  19  of the elongated member  18  is attached to the foundation  13 . The upper end portion  20  is secured to the bond beam  11  by a fastener or a washer  25  and a nut  26 , shown in  FIG. 2 . An adhesive, such as epoxy resin  30  shown in  FIG. 2 , attaches the lower end portion  19  to the foundation  13 . 
         [0033]      FIG. 2  shows details of the elongated tension member  18 , formed principally of wire rope. The lower end portion  19  has a lower stud  22  swaged into integral lower bulbous element  23 . The lower stud  22  is secured to the foundation bore  16  by an adhesive or an epoxy resin  30  placed inside the bore  16 . The lower end portion  19  can also be a threaded stud  33 , as shown in  FIG. 3 , and secured to the foundation bore  16  by means known in the art. 
         [0034]    In  FIG. 3 , the upper end portion  20  of the elongated tension member  18  includes upper stud portion  21 , swaged inside the integral upper bulbous element  24 . The upper end portion  20  passes through a sleeve  31  disposed inside a passageway  17  inside the continuous masonry bond beam  11 . 
         [0035]    The upper end portion  20  of the element  18  extends through and above the bond beam  11 . 
         [0036]    In order to install the member  18  through the masonry wall  12  after installing the wall  12 , a passageway  17  is drilled through the bond beam  11  to allow the upper end portion to pass therethrough. When building the masonry wall  12 , a sleeve  31  can be added to enclose upper portion  20  and extend a passageway  17  upwardly. A washer  25  and a nut  26  are threadedly engaged to the upper stud  21 . Tightening the nut  26  tensions the member  18  and places the masonry wall under compression. 
         [0037]    The member  18  may be constructed of a rebar  28  as shown in  FIG. 4 . The rebar  28  has an upper end portion  35  having threads  29  and a lower end portion  36 . The upper end portion  35  terminates with the welded upper stud  39  extending beyond the bond beam  11 . The upper end portion  35  is secured to the bond beam by a washer  38  and a nut  37  to tension the rebar  28  when tightening the nut  37 . The member  18  can be made of any substantially non-stretchable bar. A sleeve  33  may be provided as before to create passageway  34 . A welded, threaded lower stud  39 ′ having threads  29 ′ may be provided if desired. 
         [0038]    Alternatively, the tension member may be a long threaded rod or bolt  40 . The upper end portion  42  includes a threaded stud  39 ′ as shown in  FIG. 5 . The lower portion  41  may be threaded as shown or have some other irregularity or bulbous connector affixed thereto, as with member  18 . The upper end portion  42 , which includes welded upper stud  39 , is secured to the bond beam  11  by a fastener or a washer  43  and a nut  44 . Sleeve  47  and passageway  46  are as before. 
         [0039]    In  FIG. 6 , another embodiment of the upper portion of the tension member  18  illustrated in  FIG. 3  is shown at  48 . The apparatus is substantially identical to the upper end portion  20  illustrated in  FIG. 3  with additional features. In lieu of washer  25 , plate  50  is provided with sufficient width to provide for flanges  51  over the upper edges  55  of bond beam  11 . Subtending hook members having loop ends  53  carry horizontal rebars  54  to provide for additional strength. Sleeve  49  may terminate at the lower surface of bond beam or may continue through passageway  17  as shown in  FIG. 3 . 
         [0040]    As shown in  FIG. 7 , hook members  52  may be spacedly staggered if desired in the circumstances. 
         [0041]      FIG. 8  illustrates a two-story application of the invention with the upper portion  56  illustrated in  FIGS. 9-10 . The upper tension device  18 ′ includes the tension member  57  formed of wire rope and is preferably threadedly anchored over and to the projecting portion of upper stud  21  of upper portion  48  as illustrated in  FIG. 6 . The bulbous element  58  in this application has the wire rope  57  swaged into it as before. Element  58  is integral to an upper threaded stud portion  59  attached atop two plates  60  via washer  61  and nut  62 . Sleeve  63  is integral with nut  62  and passes through passageway  64  ( FIG. 9 ). 
         [0042]    The embodiment of  FIGS. 8-10  provides for integral female threads  65  for engagement with threaded stud portion  59 . The large number of engaged threads  65  provides for greater strength of engagement that may be desired in the circumstances. In addition, the lower end of threads  65  engages the stud  59  and allow for a shorter tension element to be used. 
         [0043]    In the utilization of the invention as shown in  FIG. 8  the upper portion of the tension device illustrated in  FIG. 3-7  may be used with the upper end of  FIG. 6  preferred. 
         [0044]    Also disclosed are methods for installing the elongated member  18  inside the masonry building  10 . The method includes removing knock-out portions  67 , shown in  FIG. 1  from vertical hollow wall sections  14 , thereby exposing a surface portion of the concrete foundation  13 . A foundation bore  16  is drilled in the foundation  13  and an adhesive  30  is placed inside the bore  16 . Tension member  18  is inserted vertically through sleeve  31  in the continuous masonry bond beam  11  and through hollow masonry units into the foundation bore  16 . The lower end portion  19  of the member  18  is attached to the foundation  13  by an epoxy resin  30 . Tensioning means or a nut  26  and a washer  25  are threadedly engaged with the upper end portion  20  of the elongated member  18 . The nut  26  is then tightened to cause the member  18  to be taut and thereby compress masonry wall  12 . 
         [0045]    The elongated member  18  can also be installed while building the masonry walls  12 . Spaced bores  16  are drilled into the concrete foundation  13 . An adhesive  30  is placed into the foundation bores  16 . A first row of hollow masonry units  15  is laid on the foundation  13 . A second row of hollow masonry units  15  is laid on the first row and vertically aligned to alternate holes of the vertically adjacent masonry units  15 , thus creating a continuous passageway with the plurality of spaced bores  16  in the concrete foundation  13 . Pluralities of member  18  are then inserted into the bores  16  through the hollow masonry units  15 . Each member  18  has a height greater than the height of the masonry wall  12 . Additional rows of masonry units  15  are laid until a predetermined height of the masonry wall  12  is achieved. A masonry bond beam  11  is poured on top of the masonry wall  12  with the sleeves  31  disposed around the upper end portion  20  of the members  18  to prevent concrete from impeding the passage of the members  18 . The upper end portion  20  of the member  18  is tensioned to compress the masonry wall  12  by threadedly engaging a washer  25  and a nut  26  with the upper end portion  20  of the members  18 . The nut  26  is tightened to tension the members  18 , and compress the masonry walls  12 . Concrete  66  is poured when appropriate. 
         [0046]    While the invention has been described with respect to certain specific embodiments, it will be appreciated that many modifications and changes may be made by those skilled in the art without departing from the spirit of the invention. It is intended, therefore, by the appended claims to cover all such modifications and changes as fall within the true spirit and scope of the invention.