Abstract:
A limited displacement, variable location, post tension anchor assembly wherein a post tension thread bar (or a thread bar attached to an SDB) can be displaced following the encapsulation of the anchor assembly in concrete. The displacement movement is in a plane perpendicular to the axis of the thread bar and is limited to the size of the anchor enclosure assembly enclosure. This device provides a mechanism to compensate for placement errors that can occur for field placement of post tension anchor assemblies in concrete structures that heretofore have been unavailable. In addition, following the correct positioning of the thread bar, there is a mechanism provided to allow for remote pressure grouting of the assembly.

Description:
CONTINUITY 
       [0001]    This application claims the benefit of U.S. provisional patent application No. 60/261,486, Doc. No. 7291 filed Jan. 13, 2001, and is a continuation-in-part of PCT patent application number PCT/US01/05733, filed Feb. 22, 2001, which designates the United States of America and claims the benefit of U.S. provisional patent application No. 60/184,049, filed Feb. 22, 2000. This application also claims the benefit of U.S. patent application Ser. No. 10/047,080 filed on Jan. 14, 2002. This application additionally claims the benefit of U.S. patent application Ser. No. 10/342,758 filed on Jan. 14, 2003. This application claims the benefit of U.S. patent application Ser. No. 10/758,601 filed on Jan. 14, 2004. This application also claims the benefit of U.S. patent application Ser. No. 11/300,055 filed on Dec. 14, 2005. These patent applications are incorporated by reference herein in their entirety. 
     
    
     BACKGROUND 
       [0002]    There are currently numerous methods available to increase the stability of earthen embankments or to construct retaining walls. Retaining walls are generally constructed by excavating soil or rock at the desired location. Once the soil mass is excavated, the remaining soil mass is typically stabilized to prevent movement of that mass. Slope stability can be increased using soil nails. For example, a slope can be stabilized by drilling holes into an existing embankment, placing steel rods in those holes and then filling the holes with cementatious grouts. By concurrently placing the steel rods and cement into an existing embankment, the slope stability can be improved so that excavation can be completed in front of that stabilized embankment (i.e. in the plane perpendicular to the orientation of rods placed into the embankment), without risk of the embankment collapsing on the construction site. In another example, rods can also be placed into generally horizontally oriented shafts drilled into existing embankments. Following insertion of the rods into the shafts, concrete or high strength grout is injected into the shafts. The concrete or grout bonds the rods to the shaft, which results in a reinforced structural column within the soil mass of the embankment. There are currently many products that can be used to construct such ground anchored and or soil nailed structures. 
         [0003]    Anchored structures can also be used to increase soil stability in situ. Anchored structures are tensioned or loaded so that the load is placed on the face of the in situ soil mass. This face load, which is induced by anchor tensioning, holds the face of the anchors and the in situ material at a predetermined position. In contrast, soil nails are typically not loaded or tensioned when they are installed, but become loaded as the earth in front of the soil nailed structure is removed. A minor amount of movement of a soil nail in situ embankment is typically assumed in design. Movement of the embankment is a manifestation of the stabilizing effect of the soil nails replacing the buttressing effect of the existing in situ material in front of the soil nailed structure. 
         [0004]    Soil nails and anchors are prone to corrosion failures. For example, if the steel rods or steel strands are used as nails or anchors, they can corrode through contact with moisture and the soil. To minimize the effects of corrosion, products have been developed to protect metal rods or strands from corrosion. For example, the “Double Corrosion System” offered by the Dywidag-Systems International uses PVC pre-grouted sheathing over metal rods to provide a water tight barrier. Florida Wire and Cable, Inc., offers plastic sheaths over a flexible steel strand for use along soil anchors. Dywidag-Systems International also offers a “Dywidur” bar, which is a non-deformed fiberglass bar bolt. Such a bolt is suitable for use in highly corrosive soil, because it is resistant to corrosion. This bolt does not have significant deformation, so its use is limited in standard grout injection to providing a better bond to the drilled shaft. These products can be effective if installed properly and can offer extended life for the anchored structure. 
         [0005]    For anchored structures, corrosion protection is a major consideration. Because metal bars used in such structures are anchored, they are more prone to break under that tension. Therefore, metal bars used in such applications typically have double or triple corrosion requirements to ensure against failure of the anchored slope. Additional corrosion protection adds to the cost of currently available soil reinforcement for anchored slope stability projects. 
         [0006]    These and other corrosion-resistant products require proper installation to prevent damage to the corrosion-resistant coating material. The sites for such installations are generally uneven (e.g., mountainous or hilly), which requires heavy equipment. Such installation conditions increase the likelihood that damage might occur to the corrosion-resistant coating material. Because corrosion reduces the service length and load capacity of metal rods or cables, corrosion is a significant problem which limits the useful life of soil nailed or anchored structures. 
         [0007]    Another typical application where ground anchors, tie backs or soil nail earth retention structures are used is for the support of temporary site excavations for construction of buildings and other structures. For some locations, such as urban areas, it can be desirable to have the ability to remove or cut through the stabilized earthen wall utilizing tie back ground anchors or soil nails. Future utility placement or maintenance in the streets or other right-of-way areas behind the shoring may necessitate either the removal of or the cutting of trenches through the in situ reinforcement used as shoring. Currently the use of steel materials dominates the types of shoring used. Due to the high shear strength of steel tendons, steel rods, or steel threadbars cutting through the material is both costly and time consuming, resulting in expensive improvements in right-of-way areas behind excavation sites shoring. 
         [0008]    In view of these shortcomings of currently available devices for soil nailed or anchored structures, there is a need for soil nails and anchors that provide strength comparable to existing materials while providing improved resistance to corrosion and can be removed or cut if necessary. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention provides methods that facilitate the construction of precast concrete post tensioned retaining walls. Both cast in place and precast concrete structures may utilize post-tensioning threadbars or SDB&#39;s with threadbar ends (as described in U.S. provisional patent application No. 60/261,486, Doc. No. 7291 filed Jan. 13, 2001, a continuation-in-part of PCT patent application number PCT/US01/05733, filed Feb. 22, 2001, which designates the United States of America and claims the benefit of U.S. provisional patent application No. 60/184,049, filed Feb. 22, 2000. Additionally described in U.S. patent application Ser. No. 10/047,080 filed on Jan. 14, 2002 which claims the benefit of U.S. patent application Ser. No. 10/342,758 filed on Jan. 14, 2003. This application claims the benefit of U.S. patent application Ser. No. 10/758,601 filed on Jan. 14, 2004.) to join and subsequently post-tension concrete components together. A typical method in current use is to provide a fixed tensioning anchor plate and nut assembly cast into the fixed concrete component to receive the threadbar connecting the components. To connect the two components a threadbar is inserted into the plate/nut assembly through the other joining component and the components are post tensioned together. Skilled tradesmen familiar with concrete forming practices are a prerequisite for correct placement of the plate nut assembly to precise tolerances so that threadbars will line up with the mating components. 
         [0010]    Therefore there is a need for a post tension plate/nut anchor assembly that can compensate for slight placement errors that can be moved to the correct anchor location within reasonable tolerances cast in either precast or cast in place concrete components. The current invention provides means and methods that allows for movements of threadbars within a post tension anchor assembly after it has been cast into either precast or cast in place concrete as required for proper alignment of the threadbars. 
         [0011]    Precast concrete structural applications that can utilize a variable location post tensioning anchor plate nut assembly include, but are not limited to, retaining walls formed by post tensioning components together to form a structural element comprised of at least two precast elements. One specific type of precast concrete retaining wall structure is formed by post tensioning precast tee shaped elements together (as described in as described in U.S. provisional patent application No. 60/261,486, Doc. No. 7291 filed Jan. 13, 2001, a continuation-in-part of PCT patent application number PCT/US01/05733, filed Feb. 22, 2001, which designates the United States of America and claims the benefit of U.S. provisional patent application No. 60/184,049, filed Feb. 22, 2000. Additionally described in U.S. patent application Ser. No. 10/047,080 filed on Jan. 14, 2002 which claims the benefit of U.S. patent application Ser. No. 10/342,758 filed on Jan. 14, 2003. This application claims the benefit of U.S. patent application Ser. No. 10/758,601 filed on Jan. 14, 2004) or by post tensioning generally tee shaped precast concrete sections to a conventional cast in place concrete foundation. Heretofore when tee sections have been used for an earth support structure, the post-tensioned anchor plate/nut assemblies used were fixed and immobile. The vertical post tensioning threadbars inserted into these fixed locations had no location flexibility therefore very precise placement of the anchors in the component is required so that the threadbars would line up with fixed anchor locations in the adjoining component. Placement of the post tensioned anchor plate/nut assemblies therefore required skilled workmen setting rigid templates placed on the proper grid to achieve correct placement of the anchors in the concrete foundation. Should errors occur in the placement process, substantial retrofitting and possibly a re-pour of a portion of a foundation would be necessary. Erroneous field situations then would both delay and add costs to the structure. The present invention allows for compensation of anchor placement errors, thereby eliminating or minimizing problems associated with misplaced post-tensioned anchor plate/nut assemblies. The following options described for the use of the present invention shown and described herein are for precast concrete earth retention structures wherein generally tee shaped sections that are vertically disposed for the retaining wall backfill support. 
         [0012]    One configuration that can utilize the present invention is an earth retention structure utilizing tee sections that are generally vertically disposed and are post tensioned to a cast in place concrete foundation. The tee sections have a front face or flange section as well as “stems” that protrude form the back of the face. There can be only one tee stem or a single tee or multiple stem sections protruding from the back or flange of the generally tee shaped section. When in place for an earth retaining structure the protruding stem or stems will be in contact with and covered with the retaining wall backfill earthen material. Therefore the earth loads due to the wall fill will be transferred to the generally vertically disposed tee section. The tee sections used for this type of application are large sections that would typically be used for long span bridges and the like and would be generally horizontally disposed for these types of structures. When used for bridges these tee sections can span large distances well over eighty feet supporting vehicular bridge traffic. For the retaining wall applications described herein the retaining wall heights could be over fifty feet. To compensate for these tremendous earth loads the tees need to have an adequate section i.e. the protruding stems need to protrude a substantial distance for the face or flange of the tee into the wall fill. This distance or depth of the tee stem can be in the order of three to five feet as measured form the rear face of the tee section. Correspondingly the post tension threadbars that are placed in ducts in the rear portion of the stems need to be high strength capable of sustaining high tensile loads that could approach 500,000 pounds of tension in each stem. Therefore accurate placement of the post tensioning anchors for structures like these is critical since any mis-alignment could result in excessive localized stresses at the component interface connection. 
         [0013]    Another application where the present invention can also be utilized is for vertical post tensioned tee section supports with panels spanning between tees for earth retention structures. When a cast in place foundation is used instead of a precast tee foundation, the vertical tees are post tensioned to a cast in place foundation. The tee sections are typically oriented in a generally vertically disposed orientation and each tee section is horizontally displaced from adjacent tee sections. The displaced distance closely corresponds to the lengths of the panel or panels supported by and bearing on the adjacent tee flanges. As with the previously described configurations, the variable position post tensioned anchor plate/nut assemblies can be cast into the foundation at locations that closely correspond to the post tension duct locations within the stems of the tee sections. Although standard, fixed, non-adjustable post-tension anchors could be used for the tee/panel combination without affecting the function of this earth retention configuration, placement of the fixed post-tensioned anchors is critical and must fall within close tolerances to avoid costly modifications. The anchors described in the present invention, placed in correspondence to the corresponding locations of the post-tension ducts within the stems of the vertically disposed tees, allow for movement of the post tension threadbars within the variable position post-tensioned anchor assembly. Since the anchor plate/nut assembly can be horizontally repositioned following the curing of the concrete foundation, minor placement errors can be compensated for with the use of the present invention. Therefore there is a need for an improvement in the existing technology relating to fixed post-tensioned anchor assemblies. The use of the present invention offers the advantage of future adjustment of the position of the anchor plate/nut assembly following installation of the anchors encapsulated and immobile in concrete thereby eliminating or minimizing subsequent structure modifications should placement tolerances be exceeded by improper field positioning of currently available conventional post-tensioning anchors. 
         [0014]    These are but two examples of the use of a variable or adjustable location post-tensioned anchor plate/nut assemblies. The retaining wall assemblies utilizing the present invention are described in the following detailed descriptions. 
         [0015]    It will be obvious to those familiar with post tensioning applications and skilled in the art that many other precast or cast in place concrete structural applications can benefit from the use of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF FIGURES 
         [0016]      FIG. 800  Partial Isometric View of Vertically Post-Tensioned Adjacent DoubleTee Wall on Cast in Place Foundation. 
           [0017]      FIG. 802  Partial Plan View of Adjacent Post-Tensioned Double Tee Wall Assembly on Cast in Place Foundation. 
           [0018]      FIG. 804  A Vertical Section View of a Variable Horizontal Location Base Post Tension Anchor Assembly and a Vertical Section View of a Fixed Location Post Tension Anchor Assembly. 
           [0019]      FIG. 806  Three Cross Sectional Views of a Variable Location Post Tension Anchor Assembly. 
           [0020]      FIG. 808  Vertical Cross Section of a Tee/Footing Wall Assembly. 
           [0021]      FIG. 810  An Isometric View of a Partially Constructed Post Tensioned Tee/Panel Wall Assembly. 
           [0022]      FIG. 812  Partial Plan View of a Partially Constructed Post Tensioned Tee/Panel Wall Assembly. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    A partially constructed post-tensioned adjacent double tee earth retaining wall assembly  830  is depicted in the isometric sketch in  FIG. 800 . Variable location post tension plate anchor assemblies  850  are shown cast into a cast in place concrete footing  821 . Post tension threadbars  832  are shown placed into the variable location post tension plate anchor assemblies  850 . The end adjacent tee  827  is shown as it would appear during a typical erection sequence with the post tension threadbars  832  inserted into the stem threadbar ducts  857  located in the tee stems  824 . The tees  827  are held in an essentially vertical position after the stem threadbar nuts  846  are threaded onto the post tension threadbars  832 . The post tensioned adjacent double tee post-tensioned adjacent double tee earth retaining wall assembly  830  as completed is able to structurally resist the earth loads placed on the wall (not shown) following the post tensioning of the post tension threadbars  832 . The wall backfill (not shown) covers and encapsulates the tee stems  824 . 
         [0024]    Referring now to  FIG. 802  a partially constructed adjacent post tensioned double tee post-tensioned adjacent double tee earth retaining wall assembly  830  is depicted in the partial plan views shown in  FIG. 802 . Partial plan view “a” shows conventional fixed location base post tension anchor assemblies  870  for comparison placed and cast into the footing  821  to correspond closely to the tee stem separation  840  and grouped in correspondence to the vertical support tee spacing  842 . Adjacent horizontally displaced support tees  827  are positioned as precisely as possible to closely correspond to the vertical support tee spacing  842 . The tee spacing deviation  844  is not equal to the vertical support tee spacing  842 , which results in excessive tee joint tolerance  855 . The excessive tee joint tolerance  855  results in either a conflict between adjacent vertical tees  827  or a wide joint between adjacent vertical tees  827  as shown in view “a”. These component location conflicts or excessively wide joints are a result of field placement errors of the fixed location base post-tensioning anchor assembly  870 . 
         [0025]    View “b” in  FIG. 802  shows a partially constructed adjacent post tensioned double tee wall assembly  830  utilizing variable location base post tension anchors  850  cast into cast in place concrete footing  821 . The adjacent horizontally displaced support tees  827  are shown without any joint conflict as a result of the use of the variable location base post tension anchors  850 . The absence of any joint conflict is due to the potential lateral horizontal movement of the post tension threadbars  832 . The lateral displacement is shown as the threadbar deviation  852  from the center of the footing threadbar duct  851 . 
         [0026]    Enlarged views of the variable location base post tension anchors  850  are shown in views “c” and “d” in  FIG. 802 . The theoretical correct location of a post tension threadbar  832  is shown in view “c”. The theoretical correct location of the variable horizontal location anchor assembly  850  corresponds to the tee stem separation  840 . The post tension threadbar  832  is at the center of a footing threadbar duct  851 . Threadbar clearance  852  represents the maximum allowable lateral deviation of the post tension threadbar  832 . 
         [0027]    A deviation from the plan location of a post tension threadbar  832  is shown in view “d” in  FIG. 802 . The post tension threadbar  832  is shown laterally displaced by the threadbar deviation  852 . The post tension threadbar  832  has therefore been moved the laterally by a distance equal to the threadbar clearance  852 . Due to this lateral displacement flexibility made possible with the use of the variable location base post tension anchors  850 , there is no joint conflict for the adjacent horizontally displaced support tees  824 . 
         [0028]    Two vertical section views of a variable position base post tension anchor assembly  850  and a typical fixed location post tension anchor assembly  870  in current use are shown in  FIG. 804 . By comparing the two assemblies many exemplary features of the available variable position base post tension anchor assembly  850  will become apparent. Vertical sections taken through the cast in place footing  821  at the fixed location post tension anchors  870  (shown in view “b” for comparison) and for the variable location base post tension anchors  850  in (view “a.”) are depicted in  FIG. 804 . 
         [0029]    Referring to view “b” in  FIG. 804  a vertical section view of a fixed location post tension anchor assembly  870  is shown. Post tension threadbar  832  is shown positioned in alignment with the vertical centerline  831  of the post tensioning threadbar duct  851 . Stressing plate washer  825  is shown with post tensioning nut  863  attached to the stressing plate washer  858  with weld  861 . Since the stress plate washer  858  is surrounded by and encapsulated within the concrete footing  821  the position of the post tension threadbar  832 , when threaded into the post tension nut  863 , is immobile (fixed). A pressure grout tube  889  is shown penetrating the footing threadbar duct  851  to direct grout to be pressure fed to the duct from the top of the cast in place footing  821 . Grouting is performed by the use of a remote pressure pump and is a process required for all conventional post tensioning applications. The fixed location post tension anchor assembly  870  is shown schematically to depict and correspond to typical post tension anchor assemblies in current use for comparison to the variable position base post tension anchor assembly  850 . 
         [0030]    Referring now to view “a” in  FIG. 804 , a vertical section of a variable horizontal location base post tension anchor assembly  850  is shown. An oversized enclosure void  872  is shown placed around the void stressing plate  854 . The oversized enclosure void  872  is larger than the variable location stress plate washer  856  as shown to allow for lateral displacement of the variable location stress plate washer  856 . The variable location stress plate washer  856 , along with the post tension nut  863 , which is attached by the weld  861 , are shown placed within the oversized enclosure duct  872 . A post tension threadbar  832  is shown inserted though the threadbar void  866  and threaded into the post tension nut  863 . The post tension threadbar  832  is shown displaced from the edge of the footing threadbar duct  851  by the threadbar clearance  852 . Correspondingly, the variable location stress plate washer  856  is displaced from the edge of the oversized enclosure void  872  by the average stress plate washer horizontal displacement  862 . In addition the pressure grout tube  890  is shown directed to the oversized enclosure void  872 , which will allow grout to be pressure injected into the oversized enclosure void  872 . To allow the grout to flow out of the oversized enclosure void  872  a grout vent void  895  is shown in the variable location stress plate washer  856 . An alternate pressure gout tube  891  is also shown along with an alternate gout vent void  893 . Since the oversized enclosure void  872  allows for horizontal movement of the post tension threadbar  832  in correspondence to the size of the threadbar void  866 , the location of the post tension threadbar  832  can be displaced as needed within the threadbar void  866  to compensate for placement errors of the variable horizontal location base post tension anchor assembly  850 . 
         [0031]    Referring now to  FIG. 806  three cross sectional views of a variable horizontal location base post tension anchor assembly  850  are shown. A vertical sectional view of a variable horizontal location base post tension anchor assembly  850  is shown in view “a” where a post tension threadbar  832  is shown partially threaded into the post tension nut  863 . The post tension threadbar  832  has been inserted through the threadbar void  866  as well as through the footing threadbar duct  851 . The post tension nut  863  and the variable location stress plate washer  856  to which it is attached are shown placed within the oversized enclosure void  872  prior to encapsulating the variable horizontal location base post tension anchor assembly  850  within the cast in place concrete footing  821 . Due to the threadbar void  866  and the size of the void oversized enclosure void  872  the post tension threadbar  832  can be horizontally displaced in any bearing or direction within the footing threadbar duct  851 . Movements shown are the average stress plate washer horizontal displacement  862  or the threadbar clearance  852  within the footing threadbar duct  851 . 
         [0032]    Horizontal sections (as indicated by the dashed cut section line in view “a”) through the post tension threadbar  832  are shown in views “b” and “c” in  FIG. 806 . In both views the void oversized enclosure void  872  and the stressing plate washer  858  are shown with a square shape. Many other commonly available shapes for the oversized enclosure void  872  (although not shown) could be used with equal effectiveness and could be used without affecting the operation of the present invention. In order to secure post tension threadbar  832  to the post tension nut  863  the post tension nut  863  must be restricted from rotating as the post tension threadbar  832  is turned. The restriction from turning can occur without the introduction of tools or other means into the void oversized enclosure duct  872  and without restricting horizontal displacements of the post tension threadbar  830  within the threadbar void  866  as is described as follows for views “b” and “c”. In this non-tensioned state for the post tension anchor assembly  850  the post tension threadbar  832 , after attachment to the post tension nut  863 , can freely move horizontally within the threadbar void  866  to correspond to the exact location of the stem threadbar duct  859  (not shown—see  FIG. 800 ). 
         [0033]    In view “b” the post tension threadbar  832  has been rotated and threaded into the post tension nut  863  resulting in the rotation of the variable location stress plate washer  856  which is shown in contact with the void oversized enclosure duct  872  at the impingement point  859 . As a result the variable location stress plate washer  856  is restricted from rotational movement allowing the post tension threadbar  832  to be threaded into the post tension nut  863  a sufficient distance for full thread contact prior to post tensioning. Following the insertion of the post tension threadbar  832  into the variable location stress plate washer  856  the post tension threadbar  832  can be both partially rotated or displaced horizontally within the confines of the threadbar void  866  as may be required to reasonably position the post tension threadbar  832  to the correct position. Although the post tension threadbar  832  can be displaced horizontally as needed for alignment the post tension threadbar  832  it is restricted from any vertical movement due to void stressing plate  854  which is necessary so that the post tension threadbar  830  can withstand vertical post tensioning loads. 
         [0034]    Referring back again to view “a” in  FIG. 806  an alternate pressure grout tube  891  is shown which, if used, has a duel function. The alternate pressure grout tube  891  is also shown in the horizontal assembly view in view “c” in  FIG. 806  as previously stated. By positioning the alternate grout tube  891  through the stressing plate washer  858  an alternate method is provided to prevent the rotation on the variable location stress plate washer  856  when the post tension bar  832  is threaded into the post tension nut  863 . To accomplish the restriction of rotation of the variable location stress plate washer  856  a bar or other rigid shaft (not shown) can be temporarily inserted into the alternate grout tube  891 , which will provide an impingement to restrict the rotation of the variable location stress plate washer  856  so that the post tension threadbar  832  can be threaded into the variable location stress plate washer  856  remotely without direct access to the variable location stress plate washer  856 . Overcoming the problem of access to the variable location stress plate washer  856  to allow the connection of the post tension threadbar  832  is an exemplary feature of this invention. 
         [0035]    A vertical cross section of a tee/footing wall assembly  860  is shown in  FIG. 808 . In this view the tee stem  824  is shown in place and post tensioned to the cast in place concrete footing  821 . This view shows a typical potential misalignment of the stem threadbar duct  857  and the footing threadbar duct  851 . A method to compensate for placement errors is an exemplary feature of the present invention which provides a mechanism to compensate for an inaccurate placement of the variable horizontal location base post tension anchor assembly  850  when incorrectly positioned and cast into the cast in place footing  821 . As shown in  FIG. 808  the post tension threadbar  832  is horizontally displaced by the threadbar clearance  852 . The variable location stress plate washer  856  is also horizontally displaced by the maximum threadbar horizontal tolerance  884 . So long as this maximum threadbar horizontal tolerance  884  is not exceeded by improper field placement of the variable position base post tension anchor assembly  850  the post tension threadbar  832  can be properly positioned within the stem threadbar duct  857  allowing for the vertical support tee  827  to be placed at the proper location. 
         [0036]      FIG. 808  also shows the component interface grout  873 , which fills the vertical tolerances between the cast in place concrete footing  821  and the tee stem  824 . The shim distance  886  is shown filled with component interface grout  873  which is contact with the base of the tee stem  824 , the top of the cast in place footing  821 , and the elastomeric sealer  888 . The elastomeric sealer  888  shown is a means to provide a seal between the top of the cast in place footing  821 , and the bottom of the tee stem  824 . The elastomeric sealer  888  also seals off the footing threadbar duct  851  and the stem threadbar duct  857  from incursion of the component interface grout  873  as it is field packed into the shim distance  886  void. Following placement of the component interface grout  873 , the post tension threadbar  832  can be post tensioned to the required force to secure the support tee  827  to the cast in place concrete footing  821 . The duct grout flow  867  (as indicated by the dotted line) results by forcing the duct grout flow  867  into the pressure grout tube  890  or the alternate grout tube  891  (not shown) at the top of the cast in place concrete footing  821 . The duct grout flow  867  proceeds sequentially into the void oversized enclosure void  872 , through the grout vent void  896  in the oversized variable location stress plate washer  856 , into and through the threadbar void  866  and finally into the stem duct  857 . Following pressure grouting all of the post tension threadbar ducts and the enclosures surrounding the post tension threadbar  832  as noted the post tension threadbar  832  will be completely encapsulated in grout. 
         [0037]    An isometric view of a partially constructed post tensioned tee/panel wall assembly  820  is depicted in  FIG. 810 . The post tensioned tee/panel wall assembly  820  is an alternate precast tee section retaining wall configuration that can be utilized to compensate for misplacements of the variable location post tension anchor assemblies  850  in the cast in place concrete footing  821 . The use of concrete wall panels  834  placed between adjacent support tees  827  can be used for reduced height earth retention structures (typically under twenty feet in height) and this combination of components is another exemplary configuration providing a means that allows for greater tolerances of placement of the wall components. The variable horizontal location base post tension anchor assemblies  850  are shown cast into the cast in place concrete footing  821  at the approximate location of the support tee  827 . Post tension threadbars  832  are shown installed into the variable horizontal location base post tension anchor assemblies  850 . Two support tees  827  are also shown post tensioned to the cast in place footing  821  with a wall panel  834  supported by the support tees  827 . Utilizing wall panels  834  to span between adjacent tees offers not only increased placement tolerance advantages but the configuration can also result in a lower cost wall system since wall panels  827  are typically available at a lower unit price than that of the support tees  827 . 
         [0038]    A partial plan view of a partially constructed post tensioned tee/panel wall assembly  820  is shown in  FIG. 812 . Variable horizontal location base post tension anchor assemblies  850  are shown cast into the cast in place concrete footing  821  to correspond to the location of the support tees  827 . The support tee  827  has a flange extension  835  to support the wall panel  834 . A wall panel  834  is shown placed between adjacent support tees  827  with the ends of the panels  827  bearing on the flange extensions  835 . The width of the flange extension  835  is less than the panel clearance displacement  838 . The panel clearance displacement  838  provides another horizontal tolerance displacement to compensate for any field placement errors of the post tension threadbars  832  in the cast in place concrete footing  821 . The combination of the use of the variable horizontal location base post tension anchor assemblies  850  with the post tensioned tee/panel wall assembly  820  provides for maximum tolerances to compensate for any field placement location deviations of either the variable horizontal location base post tension anchor assemblies  850  or the use of the fixed location base post tension anchor assemblies  870  (not shown). The previous examples are provided to illustrate without limiting the scope of the claimed invention. Other variations and or equivalents of the invention will be readily apparent to those of ordinary skill in the art and encompassed by the appended claims.