US20200173163A1

US20200173163A1 - System and method for anchoring air separation unit structures to concrete foundations

Info

Publication number: US20200173163A1
Application number: US16/683,529
Authority: US
Inventors: Bismarck N. Luna; Joseph W. Ball; Ryan C. Mierzwa; Kevin J. Saboda
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-11-29
Filing date: 2019-11-14
Publication date: 2020-06-04

Abstract

A system and method for anchoring a cold box structure of an air separation unit to a concrete foundation is provided. One such embodiment provides a concrete foundation having a plurality of reinforced concrete piers projecting vertically from a top surface of the concrete foundation and configured to anchor the cold box structure to the reinforced concrete piers using a plurality of horizontally disposed anchor bolts. Alternatively, the concrete foundation may include a plurality of hollow steel structures projecting vertically from a top surface of the concrete foundation and configured to anchor the cold box structure.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of and priority to U.S. provisional patent application Ser. No. 62/772,817 filed on Nov. 29, 2018, the disclosure of which is incorporated by reference herein.

TECHNICAL FIELD

The present invention relates generally to construction techniques for air separation plants, and more particularly to various systems and methods to secure air separation plant structures, such as a cold box structure, to concrete foundations as well as provide horizontal stability to the air separation plant structures.

BACKGROUND

Nationally recognized building codes require that structures or equipment used in an air separation plant such as cold box structures be secured to the foundation to safeguard against the destructive uplifting and shearing forces of seismic events and severe weather related events, i.e., strong winds, tornadoes, hurricanes, etc. The securing of such air separation plant structures and equipment is typically accomplished by connecting the frame of the structure or equipment to a concrete foundation through the use of steel anchor bolts embedded in the concrete foundation. The required thickness of the foundation and embedment depth of the anchor bolts are generally determined in accordance with the American Concrete Institute (ACI) Building Code Requirements for Structural Concrete (ACI 318-14). Anchor bolts are typically laid out in the foundation prior to pouring concrete, with threaded portions sticking up out of the concrete foundation high enough to be secured by a round washer and a nut. When the concrete dries, the anchor bolts would be used to secure the frame of the structure to the concrete foundation.
However, due to the large size of structures used in most air separation plants, conventional designs and procedures for anchoring such large structures to concrete foundations as described in ACI 318-14 Chapter 17 are not directly applicable. For example, many air separation plants have cold box structures that have a side dimension or diameter that can range from 10 feet (10′) to 17 feet (17′) and the height of such cold box structures can be up to 300 feet (300′). To secure such large structures to the on-site casted concrete foundation, very large size anchor bolts are typically used. Such large anchor bolts may range up to six inches (6″) in diameter with an embedment depth of six feet (6′) feet or more, whereas design using ACI 318-14 Chapter 17 is generally limited to anchors with four inch (4″) diameter and less. Some failure modes associated with anchoring of such large structures of an air separation plant with very large anchor bolts include pull-out or steel failure from excessive tensile loadings as well as concrete breakout/pryout, punching shear failures and steel failures from excessive shear loadings.
What is needed, therefore, is an improved method and system for securing air separation plant structures or equipment to reinforced concrete foundations without the use of traditional anchor bolts.

SUMMARY OF THE INVENTION

The present invention may be characterized as a system for fastening a frame of a cold box structure of an air separation plant to a concrete foundation, the system comprising: (i) a concrete foundation having a plurality of reinforced concrete piers projecting vertically from a top surface of the concrete foundation, wherein the reinforced concrete piers are arranged to project vertically from the top surface of the concrete foundation at locations adjacent to the outer perimeter of the cold box structure; (ii) a plurality of anchor bolts, each anchor bolt comprising an anchor bolt body having a first end and a threaded second end, with both ends configured to be projecting from the one of the plurality of the reinforced concrete piers in an orthogonal orientation to the vertical projection of the one of the plurality of reinforced concrete piers from the top surface of the concrete foundation, wherein the threaded second end of each of the one or more anchor bolts are configured to pass through a bore on a frame of the cold box structure; and (iii) one or more nuts configured to screw onto the threaded second end of each anchor bolt body to fasten the frame of the cold box structure to the plurality of reinforced concrete piers.
The present invention may also be characterized as a hollow steel structure assembly for fastening a cold box structure of an air separation plant to a concrete foundation, the hollow steel structure assembly comprising: one or more hollow steel structures, each hollow steel structures comprising a body defining a central axis, a length measured along the central axis and a width or diameter measured orthogonally to the central axis, the body further defining a first end configured to be embedded in the concrete foundation, and a second end configured to be projecting from the concrete foundation. The second end of the one or more hollow steel structures are configured to project from a top surface of the concrete foundation and further configured to project into the frame of the cold box structure. In some embodiments, the body of each of the one or more hollow steel structures may be a tapered configuration.
An alternative arrangement of the hollow steel structure assembly for fastening a cold box structure of an air separation unit to a concrete foundation provides the one or more hollow steel structures each having one or more alignment holes in the body proximate the second end. In such alternate embodiment, the second end of the one or more hollow steel structures are configured to project from a top surface of the concrete foundation and project adjacent to the outside perimeter of the cold box structure. The assembly would further include one or more anchor bolt assemblies configured to traverse through the alignment holes proximate the second end and couple the one or more hollow steel structures to the frame of the cold box structure in a horizontal orientation.

BRIEF DESCRIPTION OF THE DRAWINGS

While the present specification concludes with claims distinctly pointing out the subject matter that Applicants regard as their invention, it is believed that the invention will be better understood when taken in connection with the accompanying drawings which:

FIG. 1 depicts a concrete foundation having a plurality of reinforced concrete piers suitable for use in an embodiment of the present system and method for anchoring air separation unit structures to concrete foundations;

FIG. 2 depicts an air separation unit cold box structure being anchored onto a concrete foundation having the reinforced concrete piers of FIG. 1;

FIG. 3 depicts an air separation unit cold box structure being anchored onto a concrete foundation having a plurality of hollow steel structures embedded therein in accordance with another embodiment of the present system and method for anchoring air separation unit structures to concrete foundations;

FIG. 4 is a perspective view of an embodiment of the hollow steel structure suitable for use in the present system and method for anchoring air separation unit structures to concrete foundations;

FIG. 5 is a perspective view of an alternate embodiment of the hollow steel structure suitable for use in the present system and method for anchoring air separation unit structures to concrete foundations; and

FIG. 6 is a perspective view of yet another embodiment of the hollow steel structure suitable for use in the present system and method for anchoring air separation unit structures to concrete foundations.

DETAILED DESCRIPTION

Reinforced Concrete Piers
Turning to FIG. 1 and FIG. 2 of the drawings, there is shown an arrangement of reinforced concrete piers 20 used to secure structures or equipment of an air separation plant such as cold box structures 10 to a reinforced concrete foundation 15. As seen therein, reinforced concrete piers 20 are disposed on the concrete foundation in a configuration such that multiple sides of the cold box structure 10 are aligned with and adjacent to the reinforced concrete piers 20. Horizontally anchoring the cold box structure 10 of the air separation plant to the reinforced concrete piers 20 via aligned holes 25 in the cold box structure and the reinforced concrete piers 20 is used in lieu of the conventional means for anchoring cold box structures, namely using large-size vertically oriented cast-in-place anchor bolts.
Use of the reinforced concrete piers 20 for anchoring cold box structures 10 eliminates the need to design a complicated anchor bolt chairs for the large size vertical anchor bolts and simplifies the calculations for determining connection or anchoring strength. Additional advantages arising from the use of the reinforced concrete piers 20 include likely reduction in the thickness of the concrete foundation 15 when compared to concrete foundations where anchoring is accomplished using large-size vertical cast-in-place anchor bolts. This reduction in concrete foundation thickness is primarily a result of a smaller required embedment depth of the reinforcement of the concrete piers 20 and the monolithic nature of the pure concrete arrangement of the foundation and piers.
The concrete piers 20 preferably have a plurality of reinforcing bars embedded therein to provide sufficient longitudinal and transverse reinforcement to the pier and to confine the concrete when formed. Aligned horizontal thru-holes 25 are also placed in the reinforced concrete piers 20 as well as the cold box structure 10 to facilitate connection using horizontally disposed anchor bolts (not shown).
Hollow Steel Structures (HSS)
Turning now to FIGS. 3-6 of the drawings, there is shown various configurations of hollow steel structures 40 configured to be embedded in concrete foundations 35 and used to anchor cold box structures 30 or equipment of an air separation unit to a concrete foundation 35. As seen in one embodiment, the hollow steel structures 40 are vertically cast-in structures disposed at the corners and/or around the perimeter of where the cold box structure 30 is to be placed on the concrete foundation. The hollow steel structures 40 are used to connect the cold box structure 30 to the foundation 35 in lieu of the conventional means for anchoring cold box structures, namely using large-size vertical cast-in-place anchor bolts.
In various embodiments of the hollow steel structures shown in FIGS. 4-6, the one or more hollow steel structures 40 comprise a body 42 defining a central vertical axis, a length measured along the central vertical axis and a width or diameter measured orthogonally to the central vertical axis. The hollow steel structure body 42 includes a first end 44 configured to be embedded in the concrete foundation 35 and a second end 46 configured to be projecting vertically upwards from the concrete foundation 35. The projecting second end 46 of the hollow steel structures 40 are configured to project into corresponding receptacles in the frame of the cold box structure 30.
The hollow steel structures 40 may optionally include a steel plate 50 (See FIG. 4) or other reinforcing structure 52 (See FIG. 5) affixed to the body 42 proximate the first end 44 and extending in an orthogonal orientation to the central vertical axis of each of the one or more hollow steel structures 40. The steel plate 50 or other reinforcing structure 52 are configured to be embedded in the concrete foundation 35. Also, in some embodiments, the body 42 of each of the one or more hollow steel structures may be a tapered configuration as shown in FIG. 6 so as to slide into and engage corresponding receptacles in the bottom of the cold box structure 30.
Although the present arrangement for securing cold box structures or equipment of an air separation plant to a reinforced concrete foundation has been discussed with reference to one or more preferred embodiments, as would occur to those skilled in the art that numerous changes and omissions can be made without departing from the spirit and scope of the present invention as set forth in the appended claims.

Claims

What is claimed is:

1. A system for fastening a frame of a cold box structure of an air separation plant to a concrete foundation, the system comprising:

a concrete foundation having a plurality of reinforced concrete piers projecting vertically from a top surface of the concrete foundation, wherein the reinforced concrete piers are arranged to project vertically from the top surface of the concrete foundation at locations adjacent to the outer perimeter of the cold box structure;

a plurality of anchor bolts, each anchor bolt comprising an anchor bolt body having a first end and a threaded second end, with both ends configured to be projecting from the one of the plurality of the reinforced concrete piers in an orthogonal orientation to the vertical projection of the one of the plurality of reinforced concrete piers from the top surface of the concrete foundation;

wherein the threaded second end of each of the one or more anchor bolts are configured to pass through a bore on a frame of the cold box structure; and

one or more nuts configured to screw onto the threaded second end of each anchor bolt body to fasten the frame of the cold box structure to the plurality of reinforced concrete piers.

2. A hollow steel structure assembly for fastening a cold box structure of an air separation plant to a concrete foundation, the hollow steel structure assembly comprising:

one or more hollow steel structures, each hollow steel structures comprising a body defining a central axis, a length measured along the central axis and a width or diameter measured orthogonally to the central axis, the body further defining a first end configured to be embedded in the concrete foundation, and a second end configured to be projecting from the concrete foundation;

wherein the second end of the one or more hollow steel structures are configured to project from a top surface of the concrete foundation and further configured to project into the frame of the cold box structure.

3. The hollow steel structure assembly of claim 2 further comprising a steel plate or other reinforcing structure affixed to the body proximate the first end and extending in an orthogonal orientation to the central axis of each of the one or more hollow steel structures, the steel plate configured to be embedded in the concrete foundation.

4. The hollow steel structure assembly of claim 2 wherein the body of each of the one or more hollow steel structures is a tapered configuration.

5. A hollow steel structure assembly for fastening a cold box structure of an air separation plant to a concrete foundation, the hollow steel structure assembly comprising:

one or more hollow steel structures, each hollow steel structures comprising a body defining a central axis, a length measured along the central axis and a width or diameter measured orthogonally to the central axis, the body further defining a first end configured to be embedded in the concrete foundation, and a second end configured to be projecting from the concrete foundation, and one or more alignment holes in the body proximate the second end;

wherein the second end of the one or more hollow steel structures are configured to project from a top surface of the concrete foundation and further configured to project adjacent to the outside perimeter of the cold box structure; and

one or more anchor bolt assemblies configured to traverse through the alignment holes proximate the second end and couple the one or more hollow steel structures to the frame of the cold box structure in a horizontal orientation.

6. The hollow steel structure assembly of claim 5 wherein portions of the one or more hollow steel structures are filled with concrete.

7. The hollow steel structure assembly of claim 5 further comprising a steel plate affixed to the body proximate the first end and extending in an orthogonal orientation to the central axis of each of the one or more hollow steel structures, the steel plate configured to be embedded in the concrete foundation.

8. The hollow steel structure assembly of claim 7 wherein the size of the steel plate is selected such that a perimeter of the steel plate is between about 0.25 times the embedment depth of the body to about 4.0 times the embedment depth of the body.

9. The hollow steel structure assembly of claim 7 wherein the steel plates of the one or more hollow steel structures provide punching shear reinforcement to the concrete foundation proximate the one or more hollow steel structures.

10. The hollow steel structure assembly of claim 7 wherein the steel plates of the one or more hollow steel structures are further configured to be disposed below a longitudinal reinforcement within the concrete foundation.