Watertight composite straight wall post-tensioned concrete tank structure and methods for making or using same

Abstract

The subject invention pertains to composite straight wall liquid storage tanks held in persistent compression to provide superior watertightness for the life of the tank, including ACI American Concrete Institute 350 code-compliant liquid-containing composite straight wall structures with an integral full-height galvanized steel shell diaphragm fully encased in continuous shotcrete. The provided tapered composite straight wall can incorporate epoxy-bonded diaphragm sheet joints at the floor, wall, L-shaped corner posts, and T-shaped bisecting wall junction plates to support watertight connections. The external envelope and, optionally, one or more internal or bisecting walls of the structure can be provided in persistent compression by compressive post-tensioning.

We claim: 
     
         1 . A tensioning system providing structural support, watertight sealing, and post-tensioning for a straight-wall concrete tank, the system comprising:
 a corner post comprising:   a first plate comprising a first bearing surface defining a first direction and an opposite first tensioning surface,   a second plate comprising a second bearing surface defining a second direction and an opposite second tensioning surface,   a corner formed where the first plate is fixedly attached to the second plate,   a first tab connector, fixedly attached to and extending from the first plate, configured to support a first diaphragm seal with a diaphragm sheet that is oriented substantially in the first direction, and   a second tab connector fixedly attached to and extending from the second plate, configured to support a second diaphragm seal with a diaphragm sheet that is oriented substantially in the second direction;   the corner post receiving a first persistent tensile load in the first direction and a second persistent tensile load in the second direction;   the corner post providing structural support for a first persistent compressive load in the first direction and a second persistent compressive load in the second direction; and   the corner post providing a persistent watertight connection between the first tab connector and the second tab connector.   
     
     
         2 . The system according to  claim 1 , wherein the corner post is a first corner post, the system comprising a first multiplicity of tensioning strands configured and adapted to carry the first persistent tensile load in the first direction between the first corner post and a second corner post. 
     
     
         3 . The system according to  claim 2 , comprising:
 a first multiplicity of diaphragm sheets each, respectively, substantially aligned with the first direction and configured to create a persistent watertight seal between the first corner post and the second corner post.   
     
     
         4 . The system according to  claim 3 , comprising:
 a second multiplicity of tensioning strands configured and adapted to carry the second persistent tensile load in the second direction between the first corner post and a third corner post; and   a second multiplicity of diaphragm sheets each, respectively, substantially aligned with the second direction and configured to create a persistent watertight seal between the first corner post and the third corner post.   
     
     
         5 . The system according to  claim 4 , comprising:
 a third multiplicity of tensioning strands configured and adapted to carry a third persistent tensile load in a third direction between the second corner post and the third corner post; and   a third multiplicity of diaphragm sheets each, respectively, substantially aligned with the third direction and configured to create a persistent watertight seal between the second corner post and the third corner post.   
     
     
         6 . The system according to  claim 4 , comprising:
 a third multiplicity of tensioning strands configured and adapted to carry a third persistent tensile load in a third direction between the second corner post and a fourth corner post;   a third multiplicity of diaphragm sheets each, respectively, substantially aligned with the third direction and configured to create a persistent watertight seal between the second corner post and the fourth corner post;   a fourth multiplicity of tensioning strands configured and adapted to carry a fourth persistent tensile load in a fourth direction between the third corner post and the fourth corner post; and   a fourth multiplicity of diaphragm sheets each, respectively, substantially aligned with the fourth direction and configured to create a persistent watertight seal between the third corner post and the fourth corner post.   
     
     
         7 . The system according to  claim 6 , comprising:
 a first bisecting wall junction plate connecting two respective diaphragm sheets of the second multiplicity of diaphragm sheets;   a second bisecting wall junction plate connecting two respective diaphragm sheets of the third multiplicity of diaphragm sheets; and   a fifth multiplicity of diaphragm sheets each, respectively, substantially aligned with a fifth direction between the first bisecting wall junction plate and the second bisecting wall junction plate and configured to create a persistent watertight seal between the first bisecting wall junction plate and the second bisecting wall junction plate.   
     
     
         8 . The system according to  claim 7 , comprising:
 a third bisecting wall junction plate connecting two respective diaphragm sheets of the second multiplicity of diaphragm sheets;   a fourth bisecting wall junction plate connecting two respective diaphragm sheets of the third multiplicity of diaphragm sheets;   a sixth multiplicity of diaphragm sheets each, respectively, substantially aligned with a sixth direction between the third bisecting wall junction plate and the fourth bisecting wall junction plate and configured to create a persistent watertight seal between the third bisecting wall junction plate and the fourth bisecting wall junction plate;   a fifth bisecting wall junction plate connecting two respective diaphragm sheets of the fifth multiplicity of diaphragm sheets;   a sixth bisecting wall junction plate connecting two respective diaphragm sheets of the sixth multiplicity of diaphragm sheets; and   a seventh multiplicity of diaphragm sheets each, respectively, substantially aligned with a seventh direction between the fifth bisecting wall junction plate and the sixth bisecting wall junction plate and configured to create a persistent watertight seal between the fifth bisecting wall junction plate and the sixth bisecting wall junction plate.   
     
     
         9 . The system according to  claim 2 , the first corner post comprising an extruded, formed, or rolled steel section and one or more weldments added thereto; the one or more weldments forming at least a portion of the first tab connector and at least a portion of the second tab connector; the one or more weldments comprising one or more members selected from the list comprising: flat stock, angle stock, C-channel, rod, tube, or box-section steel. 
     
     
         10 . The system according to  claim 9 , the first corner post comprising a taper from a wider base dimension to a narrower top dimension. 
     
     
         11 . The system according to  claim 10 , the first plate comprising a first multiplicity of holes configured to receive the first multiplicity of tensioning strands carrying the first persistent tensile load in the first direction; and the second plate comprising a second multiplicity of holes configured and adapted to receive a second multiplicity of tensioning strands carrying the second persistent tensile load in the second direction. 
     
     
         12 . The system according to  claim 7 , first bisecting wall junction plate comprising:
 a body;   a third tab connector fixedly attached to and extending from the body, the third tab connector configured to support a first diaphragm seal with a diaphragm sheet that is oriented substantially in a primary wall direction;   a fourth tab connector fixedly attached to and extending from the body, the fourth tab connector configured to support a second diaphragm seal with a diaphragm sheet that is oriented substantially opposite the primary wall direction; and   a fifth tab connector fixedly attached to and extending from the body, the fifth tab connector configured to support a third diaphragm seal with a diaphragm that is substantially oriented with a secondary wall angle that is at an angle to the primary wall direction.   
     
     
         13 . The system according to  claim 12 , wherein the body comprises a T cross section. 
     
     
         14 . The system according to  claim 12 , wherein the body comprises at least one cross section selected from the group consisting of a polygonal cross section, an oval cross section, and a round cross section. 
     
     
         15 . The system according to  claim 1 , comprising:
 a first post-tensioned shotcrete wall bearing against the first bearing surface and substantially aligned with the first direction; and   a second post-tensioned shotcrete wall bearing against the second bearing surface and substantially aligned with the second direction.   
     
     
         16 . The system according to  claim 1 , comprising:
 a cast in place (CIP) concrete floor comprising one or more connection grooves configured and adapted to receive at least the first multiplicity of diaphragm sheets and provide a persistent watertight seal therewith.   
     
     
         17 . A method for constructing a watertight and durable composite straight wall post-tensioned tank structure at a construction site, the method comprising:
 a) performing a site layout and surveying to establish sufficient precision and accuracy in a set of control points at the construction site;   b) fine-grading a subgrade for proper elevation with respect to the set of control points;   c) casting a set of working slabs on the subgrade and laying out edge forms thereon for a tank floor;   d) setting floor steel and corresponding wall dowels within the edge forms;   e) setting a groove formwork to create in the floor one or more corner connection grooves (CCG) and one or more wall connection grooves (WCG);   f) casting concrete within the edge forms to create a floor comprising the CCG and WCG;   g) allowing the floor to cure at least 12 hours to achieve a predetermined strength;   h) stripping the groove formwork;   i) setting a set of four corner posts into the CCG in the floor;   j) confirming alignment, position, and plumb of each respective corner post;   k) sealing each respective corner post into the CCG in the floor;   l) erecting a multiplicity of diaphragm sheets and bisecting wall junction plates to form a respective diaphragm in each of two long, straight, external walls, with each respective diaphragm sheet and bisecting wall junction plate set in the WCG, mechanically connected to adjacent diaphragm sheet(s) or adjacent bisecting wall junction plate(s), or secured into a respective tab connector of each respective corner post to create a mechanical joint for future epoxy injection;   m) sealing each respective diaphragm sheet, bisecting wall junction plate, and corner post into the WCG in the floor;   n) positioning and tying a first layer of wall reinforcing steel on an exterior side of each respective diaphragm, to create a first layer of outer wall reinforcing steel;   o) applying shotcrete in thin successive layers until the first layer of outer wall reinforcing steel is fully encapsulated between respective bearing surfaces of the respective corner posts at each end of each respective outer wall, forming a first outer layer of reinforced shotcrete;   p) positioning a multiplicity of post-tensioning ducts and connecting a respective end of each duct to a respective corner post for each of the two long, straight, external walls;   q) positioning and tying a second layer of wall reinforcing steel outside of the post-tensioning ducts, to create a second layer of outer wall reinforcing steel;   r) applying shotcrete in thin successive layers until all outside components for the two long external walls are fully encapsulated between respective bearing surfaces of the respective corner posts at each end of each respective outer wall, forming a second layer of reinforced shotcrete;   s) positioning and tying a third layer of wall reinforcing steel on the inside face of the diaphragm and bisecting wall junction plates for the two long external walls; and   t) applying shotcrete in thin successive layers until the diaphragm, the top portion of the “T” directly connecting respective diaphragm sheets within the two long external walls of each respective bisecting wall junction plate, but not the shaft of the “T” that will connect to the diaphragm in each respective bisecting wall, and the third layer of wall reinforcing steel on the inside face of the diaphragm and bisecting wall junction plates are fully encapsulated between respective bearing surfaces of the respective corner posts at each end of each respective outer wall, forming a third layer of reinforced shotcrete to substantially complete the concrete structure of the two long external walls.   
     
     
         18 . The method according to  claim 17 , comprising:
 u) building a first one of two perpendicular short external end walls and a center primary bisecting wall, following the steps (l) through (t), omitting bisecting wall junction plate(s) and tensioning ducts where not required;   v) building two additional primary bisecting walls and one secondary bisecting wall therebetween, following the steps (l) through (t), omitting tensioning ducts where not required; and   w) building a second one of two perpendicular short external end walls, following the steps (l) through (t), bisecting wall junction plate(s) and tensioning ducts where not required.   
     
     
         19 . The method according to  claim 18 , comprising:
 x) epoxy sealing each respective vertical joint formed between each respective diaphragm sheet, bisecting wall junction plate, and corner post tab connector with epoxy injection;   y) verifying proper concrete strength gain in at least one wall;   z) inserting and threading through each respective post-tensioning duct a respective post-tensioning strand and attaching barrel bolts thereto at each respective end, bearing on each respective corner post;   aa) post-tensioning all four external walls; and   bb) after post-tensioning all four external walls, applying shotcrete in thin successive layers on and between respective tensioning surfaces of the respective corner posts at each end of each respective outer wall until the first layer of outer wall reinforcing steel is fully encapsulated, forming a first outer layer of reinforced shotcrete.   
     
     
         20 . The method according to  claim 19 , comprising:
 cc) applying shotcrete to each external surface formed in the preceding steps, to create a smooth homogenous cover coat of shotcrete providing minimum coverage requirements and a joint-free surface, to produce the watertight and durable composite straight wall post-tensioned tank structure.   
     
     
         21 . A persistent watertight post-tensioned concrete composite straight wall tank comprising:
 a first persistent watertight post-tensioned concrete composite corner;   a second persistent watertight post-tensioned concrete composite corner;   a third persistent watertight post-tensioned concrete composite corner;   a first persistent watertight post-tensioned concrete composite straight wall connecting the first corner and the second corner;   a second persistent watertight post-tensioned concrete composite straight wall connecting the second corner and the third corner;   a third persistent watertight post-tensioned concrete composite straight wall connecting to the first corner; and   a persistent watertight cast in place (CIP) concrete composite floor comprising one or more connection grooves aligned respectively with each of the first corner, the second corner, and the third corner, and one or more wall connection grooves aligned respectively with each of the first wall, the second wall, and the third wall.   
     
     
         22 . The persistent watertight post-tensioned concrete composite straight wall tank according to  claim 21 , the third wall connecting the first corner and the third corner to form a triangular tank. 
     
     
         23 . The persistent watertight post-tensioned concrete composite straight wall tank according to  claim 21 , comprising:
 a fourth persistent watertight post-tensioned concrete composite corner; and   a fourth persistent watertight post-tensioned concrete composite straight wall connecting the third corner and the fourth corner;   the third wall connecting the first corner and the fourth corner; and   the fourth wall connecting the fourth corner and the third corner to form a quadrilateral tank; and   the floor comprising one or more connection grooves aligned respectively with each of the each of the fourth corner, and the fourth wall.   
     
     
         24 . The persistent watertight post-tensioned concrete composite straight wall tank according to  claim 23 , wherein the third wall forms a first corner angle relative to the first wall at the first corner and the second wall forms a second corner angle relative to the first wall at the second corner; the first corner angle and the second corner angle each respectively being substantially equal to 90°. 
     
     
         25 . The persistent watertight post-tensioned concrete composite straight wall tank according to  claim 24 , wherein the fourth wall forms a third corner angle relative to the second wall at the third corner and the fourth wall forms a fourth corner angle relative to the third wall at the fourth corner; the third corner angle and the fourth corner angle each respectively being substantially equal to 90°, thus forming a square or rectangular tank. 
     
     
         26 . The persistent watertight post-tensioned concrete composite straight wall tank according to  claim 24 , wherein the fourth wall forms a third corner angle relative to the second wall at the third corner and the fourth wall forms a fourth corner angle relative to the third wall at the fourth corner; the third corner angle being greater than 90°; and the fourth corner angle being less than 90°, thus forming an irregular four-sided polygonal tank. 
     
     
         27 . The persistent watertight post-tensioned concrete composite straight wall tank according to  claim 23 , comprising:
 a total of n persistent watertight post-tensioned concrete corners, where n is a positive integer greater than or equal to 3; and   a total of n persistent watertight post-tensioned concrete composite straight walls;   each wall respectively connecting a respective corner with exactly one other corner;   each corner respectively connecting a respective wall with exactly one other wall to form a closed and non-intersecting n-dimensional polygonal tank; and   the floor being configured and adapted to support a persistent watertight seal between the floor and each respective wall and corner.   
     
     
         28 . The persistent watertight post-tensioned concrete composite straight wall tank according to  claim 21 , comprising:
 a first internal diaphragm encased substantially within the post-tensioned concrete of the first wall;   a second internal diaphragm encased substantially within the post-tensioned concrete of the second wall; and   a third internal diaphragm encased substantially within the post-tensioned concrete of the third wall;   one or more of the connection grooves in the floor aligned respectively with, and configured and adapted to receive and support a seal to a portion of each of the first internal diaphragm, the second internal diaphragm, and the third internal diaphragm, respectively.   
     
     
         29 . The persistent watertight post-tensioned concrete composite straight wall tank according to  claim 28 , wherein each respective diaphragm comprises a multiplicity of diaphragm sheets joined together with persistent watertight seals. 
     
     
         30 . The persistent watertight post-tensioned concrete composite straight wall tank according to  claim 28 , comprising:
 a first sealed and loaded corner post forming a portion of the first corner and configured and adapted to:
 provide persistent post-tension to the first wall, 
 provide persistent post-tension to the third wall, 
 support a persistent seal with the first internal diaphragm, and 
 support a persistent seal with the third internal diaphragm; 
   the floor comprising one or more connection grooves each respectively configured and adapted to receive therein and support a respective persistent seal with the first sealed and loaded corner post.   
     
     
         31 . The persistent watertight post-tensioned concrete composite straight wall tank according to  claim 21 , comprising:
 a first persistent watertight concrete bisecting junction;   a second persistent watertight concrete bisecting junction; and   a first persistent watertight concrete composite straight bisector connecting the first bisecting junction and the second bisecting junction, the first bisector substantially encasing a first bisecting diaphragm therein;   the first bisecting junction comprising a first bisecting junction plate encased substantially within and forming a connection between the second wall and the first bisector;   the second bisecting junction comprising a second bisecting junction plate encased substantially within and forming a connection between the third wall and the first bisector;   the floor comprising one or more connection grooves each respectively configured and adapted to receive therein and support a respective persistent epoxy seal with the first bisecting diaphragm, the first bisecting junction plate, and the second bisecting junction plate.   
     
     
         32 . The persistent watertight post-tensioned concrete composite straight wall tank according to  claim 31 , comprising:
 a third persistent watertight concrete bisecting junction;   a fourth persistent watertight concrete bisecting junction;   a fifth persistent watertight concrete bisecting junction;   a sixth persistent watertight concrete bisecting junction;   a second persistent watertight concrete composite straight bisector connecting the third bisecting junction and the fourth bisecting junction, the second bisector substantially encasing a second bisecting diaphragm therein; and   a third persistent watertight concrete composite straight bisector connecting the fifth bisecting junction and the sixth bisecting junction, the third bisector substantially encasing a third bisecting diaphragm therein;   the third bisecting junction comprising a third bisecting junction plate encased substantially within and forming a connection between the second wall and the first bisector;   the fourth bisecting junction comprising a fourth bisecting junction plate encased substantially within and forming a connection between the third wall and the first bisector;   the fifth bisecting junction comprising a fifth bisecting junction plate encased substantially within and forming a connection between the first bisector and the second bisector;   the sixth bisecting junction comprising a sixth bisecting junction plate encased substantially within and forming a connection between the first bisector and the second bisector;   the floor comprising one or more connection grooves each respectively configured and adapted to receive therein and support a respective persistent epoxy seal with the second bisecting diaphragm, the third bisecting diaphragm, the third bisecting junction plate, the fourth bisecting junction plate, the fifth bisecting junction plate, and the sixth bisecting junction plate.   
     
     
         33 . The persistent watertight post-tensioned concrete composite straight wall tank according to  claim 32 , comprising:
 a seventh persistent watertight concrete bisecting junction;   an eighth persistent watertight concrete bisecting junction; and   a fourth persistent watertight concrete composite straight bisector connecting the seventh bisecting junction and the eighth bisecting junction, the fourth bisector substantially encasing a fourth bisecting diaphragm therein;   the seventh bisecting junction comprising a seventh bisecting junction plate encased substantially within and forming a connection between the second wall and the fourth bisector;   the second bisecting junction comprising an eighth bisecting junction plate encased substantially within and forming a connection between the third wall and the fourth bisector;   the floor comprising one or more connection grooves each respectively configured and adapted to receive therein and support a respective persistent epoxy seal with the fourth bisecting diaphragm, the seventh bisecting junction plate, and the eighth bisecting junction plate.   
     
     
         34 . The persistent watertight post-tensioned concrete composite straight wall tank according to  claim 21 , comprising:
 a first plurality of post-tensioning ducts encased within the first wall and connected at opposing ends between the first corner and the second corner, each respective duct of the first plurality of ducts covering at least one respective strand of a first plurality of post-tensioning strands configured and adapted to carry a first tensile load between the first corner and the second corner; and   a second plurality of post-tensioning ducts encased within the second wall and connected at opposing ends between the second corner and the third corner, each respective duct of the second plurality of ducts covering at least one respective strand of a second plurality of post-tensioning strands configured and adapted to carry a second tensile load between the second corner and the third corner;   wherein the first corner and the second corner are configured and adapted to bear the first tensile load and transfer the first tensile load into a first persistent compression in the first wall; and   wherein the second corner and the third corner are configured and adapted to bear the second tensile load and transfer the second tensile load into a second persistent compression in the second wall.   
     
     
         35 . The persistent watertight post-tensioned concrete composite straight wall tank according to  claim 21 , having a liquid storage capacity between 15,000 gallons and 1.5 million gallons, a wall height greater than 15 feet, and a measured leakage of less than 0.05% per day, based on volume. 
     
     
         36 . A sealed and loaded corner post useful for providing concurrent structural support, post-tensioning, and watertight sealing, the sealed and loaded corner post comprising:
 a first bearing surface defining a first direction effectively normal thereto, the first bearing surface configured and adapted to transmit a first persistent compressive load oriented substantially in the first direction;   a second bearing surface defining a second direction effectively normal thereto, the second bearing surface configured and adapted to transmit a second persistent compressive load oriented substantially in the second direction, the second direction separated from the first direction by a corner angle;   a first tab connector configured and adapted to support a first persistent watertight diaphragm seal with a diaphragm sheet that is oriented substantially in the first direction; and   a second tab connector configured and adapted to support a second persistent watertight diaphragm seal with a diaphragm sheet that is oriented substantially in the second direction;   the sealed and loaded corner post configured and adapted to provide structural support for the first persistent compressive load and the second persistent compressive load; and   the sealed and loaded corner post configured and adapted to provide a persistent watertight connection between the first tab connector and the second tab connector.   
     
     
         37 . The sealed and loaded corner post according to  claim 36 , comprising:
 a third bearing surface defining a third direction effectively normal thereto, the third bearing surface configured and adapted to transmit a third persistent compressive load oriented substantially in the second direction, the corner angle being a first corner angle, and the third direction separated from the first direction by a second corner angle; and   a third tab connector configured and adapted to support a third persistent watertight diaphragm seal with a diaphragm sheet that is oriented substantially in the third direction;   the sealed and loaded corner post configured and adapted to provide structural support for the third persistent compressive load; and   the sealed and loaded corner post configured and adapted to provide a persistent watertight connection between the first tab connector and the third tab connector, and between the third tab connector and the second tab connector.   
     
     
         38 . A persistent watertight concrete bisecting junction useful in the construction of a persistent watertight post-tensioned concrete composite straight wall tank, the persistent watertight concrete bisecting junction comprising:
 a first straight concrete wall substantially oriented in a first direction, the first wall encasing a first diaphragm sheet and a second diaphragm sheet;   a second straight concrete wall bisecting the first wall and forming a corner angle therebetween, the second wall encasing a third diaphragm sheet;   a bisecting junction plate encased substantially within and forming a structural connection between the first wall and the second wall, bisecting junction plate connected to and forming a respective persistent watertight seal with each of the first diaphragm sheet, the second diaphragm sheet, and the third diaphragm sheet, respectively; and   a floor supporting each of the first wall, the second wall, and the bisecting junction plate, the floor comprising one or more connection grooves each respectively configured and adapted to receive a respective portion therein and support a respective persistent watertight seal with each of the bisecting junction plate, the first diaphragm sheet, the second diaphragm sheet, and the third diaphragm sheet, respectively.