The following is a tabulation of some prior art that presently appears relevant:
This invention combines the ease of erection and load carrying capabilities of scaffolding with a simplified concrete forming system. The forming system includes scaffold frames as the form's vertical support and walers as the form's horizontal support. It is based upon the two form sides being independent of each other by having minimal or no form ties or other internal bracing extending through the concrete from form side to form side. The scaffold forming system may be used with any type of concrete or other cementicious material although it is best suited for cementicious materials or placement processes that minimize the hydrostatic pressure exerted by the cementicious material when placed inside the forms.
Cast-in-place concrete is well known and widely used throughout the construction industry and considered to be one of the highest quality and more desirable construction systems used today. However, cast-in-place concrete has two major drawbacks. First, it uses internal form ties that extend from form side to form side, through the concrete, to hold the two sides of a concrete from together and are necessary due to the high amount of hydrostatic pressure created by wet concrete in a vertical form. Second, concrete formwork is expensive, due in large part by the use of form ties, and this higher cost results in buildings being built using other materials and/or systems.
The elimination of form ties by using external bracing will not only greatly decrease the cost of cast-in-place concrete, but also remove obstructions inside the form face that cause problems in using form liners or stay-in-place forms. With an obstruction free form face, larger form liners can be quickly, and inexpensively, set in place prior to concrete placement and easily removed after concrete placement. In addition, an obstruction free form face enables stay-in-place wall claddings to be either forms themselves or set inside and be supported by forms and in both cases become permanently bonded to the concrete as it cures and provided an attractive wall cladding.
The scaffold forming system is designed to withstand high amounts of hydrostatic pressure using external bracing only and accomplished by the scaffold frame's depth that can act like a vertical truss spanning from the top to bottom of the form and thereby eliminating the need for form ties. In addition, the forming system can be used with low hydrostatic pressure producing concrete or placement processes, which further reduce the formwork costs.
This invention is a forming system for one or both sides of a two sided, concrete forming system used to cast walls, columns and other vertical concrete structures. It combines the ease of erection and load carrying capabilities of scaffolding with a greatly simplified concrete forming system. For purposes of this disclosure the term wall will include columns and other vertical concrete structures.
The forming system includes scaffold frames as the form's vertical support and walers as the form's horizontal support. The scaffold frames act like vertical trusses spanning from the top to the bottom of the structure to be cast. The walers provide horizontal support by spanning from scaffold frame to scaffold frame and thereby transfer any lateral load to the scaffold frames. The scaffold frames, acting like trusses, then transfer that load to the scaffold frame's top and/or bottom which are fixed in place. Since both the scaffold frame and the walers are external braces, they eliminate the need for form ties or other such internal bracing.
The scaffold frame can act as a truss, fixed on both ends (top and bottom) or as a cantilever truss fixed only at its bottom. The key to whether the scaffold frames are fixed at one or both ends and to the spacing of the scaffold frames is the amount of hydrostatic pressure contained inside the forms at any one time. Conventional wet concrete exerts tens of thousands of pounds of hydrostatic pressure on forms and thereby the scaffold frames must be spaced closely together and fixed at the top and the bottom. On the other hand, special concrete or other cementicious mix designs or placement processes can greatly reduce the freshly mixed concrete's hydrostatic pressure and thereby enable the scaffold frames to be spaced further apart and/or be fixed only at their bottom.
One such concrete placement process that minimizes the amount of hydrostatic pressure in the forms is called the Thixotropic Concrete Forming System and is copending application Ser. No. 13/374,839 filed Jan. 17, 2012 and incorporated herein by reference. This new placement process greatly reduces the amount of hydrostatic pressure in a form at any one time and thereby eliminates the need for heavy bracing or form ties. This is accomplished by using the thixotropic properties of no-slump concrete which only exerts hydrostatic pressure when vibrated. Therefore, when using this process, the amount of the hydrostatic pressure in the forms at any one time is minimized by casting no-slump concrete into the forms and minimizing the amount of that concrete being vibrated at any one time. There may be other methods of eliminating or reducing the hydrostatic pressure in cementicious materials and may include the cementicious material envisioned for 3D printing of walls and rapid setting cementicious materials.
The scaffold forming system can be set in place on or adjacent to any surface on which a wall can be cast. The form setting process begins by positioning and securing the scaffold frames directly or indirectly to the surface using base braces. Base braces may be attached to and a part of the scaffold frame or they may be separate devices used to secure a scaffold frame. Typically the base brace on the interior side of the wall is set and aligned first, assuming there is an interior and exterior, to provide a control point to which the exterior base brace can be positioned. The base braces secures the bottom of the scaffold frames and may also be used to brace the bottom of the forms.
Once the bottom of the scaffold frame is secured, its front leg is height adjusted to a predetermined level which sets the wall's casting height. After the scaffold frame's front leg is height adjusted the scaffold frame's second leg is height adjusted to plumb the scaffold frame. The second leg may be secured to the surface or ground or braced at an angle by a third leg to help the scaffold frame resist the lateral pressure. The second and each additional leg act to brace the front leg. The greater the scaffold frame's depth, i.e. distance between the front and the second legs, the stronger it becomes. The scaffold frames are also stack-able to any height and can accommodate scaffold boards.
The scaffold frames are vertically oriented and as each scaffold frame is set in place, it is braced upright by a waler and/or a cross brace attached to an adjacent scaffold frame. The walers can optionally be locked to the scaffold frames and thereby creating a rigid bracing system.
After adjoining scaffold frames are set and adjusted, the remaining walers are set in place and horizontally span from scaffold frame to scaffold frame. The walers are set into saddles attached to the scaffold frame that are designed to brace the walers in a rigid and straight alignment.
Once the walers are secured and aligned, the forms are set in place and in one embodiment, the back of the forms are equipped with a hanging mechanism to enable the forms to simply hang onto the walers. Since the walers are in alignment and the forms have the same depth, the front of the forms will also be in alignment for the concrete. The forms can be attached to one another or they can simply be butted together since the freshly mixed concrete will be fairly dry and thereby not prone to leaking between small form seams. The corner forms may overlap and be butted together or may be attached to one another. The ability to simply hang and butt the forms together greatly speeds the forming and stripping processes.
Each form may be the full height of the wall or the forms may be vertically stacked either before or while the concrete is being placed. When forming for the Thixotropic Concrete Forming System, one side of the forms are fully set before concrete placement while the other side is set in two or more levels during the concrete placement. This results in a short form side that enables visual observation of the vibration and spreading of the no-slump concrete near the bottom of the form, which is very difficult or not possible to see deep down into a tall form.
The Thixotropic Concrete Forming System also minimizes the hydrostatic pressure inside the forms at any one time so that a top form clamp may not be needed and the scaffold frames on both form sides function like a cantilever fixed only at its bottom. When higher levels of hydrostatic pressure are present, a top form clamp is used to tie the two sides together.
Depending upon the amount of hydrostatic and other lateral pressure on the forms, the corners can simply butt together or special corner walers can be used. For example with minimal hydrostatic pressure, the outside corners are such that they allow one corner form and its scaffold frame and walers to extend past the adjacent corner form which butts into the face of the extending form.
When higher, more typical amounts of hydrostatic pressure are present, a special, adjustable corner waler is used. This corner waler fits inside the web of an I-beam waler and easily slides in and out for length adjustment. The corner end connects to the adjacent corner end to form a perfect 90° angle and locks the two sides together. The corner waler can be used for both inside and outside corners.
The scaffold forming system can also be used as formwork for a concrete soffit around the exterior perimeter of the wall. A concrete soffit not only strengthens the wall from lateral forces since it acts like a rib and but it also facilitates placing a concrete roof since the soffit provides the bottom portion of a roof overhang.
This invention is a forming system for one or both sides of a two sided, concrete form used to cast walls, columns and other vertical concrete structures. It combines the ease of erection and load carrying capabilities of scaffolding with a greatly simplified concrete forming system that does not utilize form ties or other internal bracing. The forming system includes scaffold frames as the form's vertical support and walers as the form's horizontal support.
When freshly mixed concrete exerts hydrostatic pressure on the forms it pushes the forms outward and therefore the forms must be braced against such pressure. The forms are braced by horizontal walers which in turn are braced by vertical scaffold frames which are also braced. The scaffold frames act like vertical trusses spanning from the top to the bottom of the wall being cast. The walers provide horizontal support by spanning from scaffold frame to scaffold frame and thereby transferring any lateral load to the scaffold frames. The scaffold frames, acting like trusses, then transfer that load to the scaffold frame's top and/or bottom which are secured in place. Therefore, all of the scaffold forming system's bracing is external.
The scaffold forming system is erected by first securing, at predetermined locations, the scaffold frames to the top or the side of the surface on which the wall is being cast. This can be done by directly securing the scaffold frame to the surface using fasteners well known in the art or indirectly by securing the scaffold frame to another device that is directly secured to the surface. For purposes of this disclosure “secure” shall mean to fasten, fix in place or brace and the term “surface” shall encompass a floor, slab, foundation, stem wall and the top of an existing wall or any other structure capable of having a wall built on it.
One embodiment of this invention is the use of base braces 1 to secure one or more scaffold frames 10 to the surface 5. The base brace 1 may be attached to and a part of each scaffold frame 10 or it may be a separate device used to secure one or more scaffold frames 10 to the surface 5. It may be of any size or shape and also perform other functions.
The base braces 1 may also be used away from the surface 5 by first attaching a base plate 2 to the surface's 5 side as shown in
In
In
In all of
Depending upon the design, the base braces 1 may also have a front side 8 which aligns the bottom of the forms and comes into direct contact with the backside of the forms and thereby provide the bracing to keep the bottom of the forms in a straight alignment.
The vertically oriented scaffold frame 10 has two or more legs to facilitate a much deeper scaffold frame, i.e. distance from the front leg 11 to the second or third leg. The greater the scaffold frame's 10 depth, the greater its strength to withstand loads transferred from the walers. Generally, the front leg 11 is in the vertical position and the second leg 12 in either a vertical or a slopped position and braces the front leg 11. Additional legs may also be used in either a vertical or slopped position and provide further bracing to the front leg 11.
Casting exterior building walls is a common application for this forming system and such walls have an interior side 55 having a floor (surface 5) and an exterior side 56 comprised of the ground.
After the second scaffold frame 15 is set, a cross brace 16 is attached from the first scaffold frame 14 to the second scaffold frame 15 as shown in
After cross bracing the first two scaffold frames, an optional locking waler 35 is attached from the first scaffold frame 14 to the second scaffold frame 15 as shown in
The scaffold frame 10 is used to keep the cast-in-place concrete wall plumb and to support and brace the walers 30 that are used to support the forms. The scaffold frames 10 may also be used as scaffolding to support workers.
The primary purpose of all walers is to provide an elongated, continuous horizontal support to the forms and thereby they must be sufficiently rigid to withstand the lateral pressure exerted on the forms over the span from scaffold frame to scaffold frame. As such, the walers may be made of any sufficiently strong materials and profile.
Since the scaffold frames are set apart in predetermined locations, the wales 30 are elongated and span the distance between adjacent scaffold frames 10 and are connected to the scaffold frames 10 by saddles 20. The scaffold frames 10 have two or more saddles 20 spaced vertically apart that are used to connect the ends of the walers 30 to the scaffold frame 10 to facilitate the transfer of the lateral loads, i.e. hydrostatic pressure, wind, etc., placed on the walers 30 to the scaffold frames 10. The saddles 20 provide the walers 30 with both vertical and horizontal support with the vertical support simply a surface on which the walers are laid. The horizontal support against the lateral pressure is by backstops 23 that are part of the saddle 20 and secure the waler 30 from being pushed away from the concrete pressure.
In one configuration the walers 30 are I-beams with the flanges 33 removed at both ends to create tongues 32 protruding from the web 37 at the ends as shown in
In another configuration the walers 30 are secured to the saddle 20 by a set screws located in the saddle's backstop 23 as shown in
In another configuration, a channel section is used as the saddle 20 as shown in
The saddle's backstop 23 may be a fixed vertical member such as a dowel or flange or it may be one or more removable pins.
The walers 30 horizontal support may be either contained by or fixed to the saddles 20 and this distinction greatly affects the waler's 30 strength. When the walers 30 are contained, there is a small amount of space inside the saddle 20 for the walers to move or rotate horizontally and as the concrete pressure pushes the walers 30 outward, the walers 30 are pressed up against the saddle's backstop 23 which prevents further horizontal movement. Fixing the walers 30, on the other hand, locks the walers in place and prevents any horizontal movement by using pins, set screws, dowels, notches, wedges, and other means known in the art. Fixing a waler 30 into the saddle 20, greatly increases the waler's strength and enables it to withstand higher level of concrete's pressure or span longer distances.
In another configuration each row of walers 30 are in the same plane to provide consistency and to simplify the form attachment. In order to accomplish this the tongues 32 must either butt up to each other in the saddles 20 or one tongue must be above the other such that they overlap in the saddle 20. The tongues 32 can overlap by attaching a protruding plate 36 to the top or bottom of the waler's web 37 on one end of the waler 30 and notching the waler's flange 33 on the second end so that the web protrudes as the tongue 32 as shown in
In one preferred embodiment, the walers 30 are I-beams having a flange 33 that extends upright, as shown in
Another embodiment of this invention is the forms 40 which can be vertically or horizontally oriented (taller than wider or wider than taller). The forms 40 butt together on their sides and may have edges that overlap and may also be clamped together from their backsides 41. The forms' backsides 41 are positioned against the walers' 30 and base brace's 1 front sides 8 which are in vertical alignment. The forms 40 are attached to the walers 30 by fasteners 42 positioned on the form's backside 41.
The form's face 47 of this invention is obstacle free, which means there are no form ties extending through or between the form faces 47 . This requires the forms 40 to be attached to the walers 30 from the form's backside 41 for horizontal bracing and vertical support. A variety of forms known in the art may be used to accomplish this including plywood and there are several methods known in the art that may be used to attach the forms 40 to the walers 30 such as screwing a screw through a hole in the waler's front flange 34 into the form's backside 41 or using a hook attached to the backside 41 that hooks over all or part of the waler 30.
For example,
The hanging forms may be reinforced with ribs 43 or may be solid as shown in
In another configuration for attaching the forms to the walers, longer fasteners 42 are attached to the form's backside 41 that are capable of reaching over or through a square or rectangular waler 30 several inches wide.
Another embodiment of this forming system is a special corner waler that is quickly set, easily adjustable and forces square corners.
The corner waler 60 may be of any fixed length and is easily shifted inside the web 37 until the desired length from the saddle 20 to the corner 65 is reached. When the corner waler 60 is set, a clamp 66 is positioned over the head 62 to firmly fix the head 62 against the inside of the web 37.
At the corner 65 where the corner walers 60 intersect at a 90 degree angle, one corner waler 60 sits on top of the second and pins 31 are set into two or more holes 22 to lock the corner walers 60 together. The slot 67 of an outside corner block 70 is fit over the two corner walers 60 and pins 31 are inserted into holes 22 so as to connect the outside corner block 70 to the two corner walers 60. This has the effect of producing a 90 degree corner while locking two intersecting lines of walers together.
Depending upon the distance from the waler 30 to the corner 65, one or more scaffold frames 10 may be used to support the corner waler 60 near the corner 65. The corner walers 60 are secured in position by base plates 1, blocks 9 or saddles 20 as the case may be. The corner walers 60 are fixed in position by the combination of the head 62 being held inside the web 37 by the clamp 66 and either a base plate 1, block 9, or saddle 20 firmly securing the body 61 and finally by the pins 31 locking the intersecting corner walers 60 together in a 90 degree angle, all shown in
The corner walers 60 and the extension blocks 63 may be used on the interior and exterior side of a wall and also for outside or inside corners.
Another embodiment of this forming system is that the scaffold frame on one side of the wall can be completely independent from the forming system on the other side of the structure. The scaffold frame is vertically and horizontally self braced and needs no support or other bracing from either the forming system on the other side of the wall or any embedments in the structure. As such, the scaffold frames on the two sides of a wall being cast are completely independent of each other. There are several advantages of this, one of which is that the formwork and/or bracing on one or both sides of the wall can be set during the casting of the wall, to facilitate the Thixotropic Concrete Forming System's concrete placement process.
Another embodiment of the scaffold forming system is that the scaffold frames can be used as shoring for concrete roofs or ceiling/floors.
The soffit form can also be positioned on the interior side 55 of the wall and thereby used as part of the shoring and forming for a ceiling/floor cast above it. In this case the walls would be cast first and then the casting would proceed to the ceiling/floor area above the scaffold frames.
The forms of this invention rely upon the base braces, walers and an optional top clamp for lateral pressure support and do not use form ties. The elimination of form ties produces an obstacle free form face 47 on or between the forms 40 as shown in
In another embodiment of this invention, the two form sides may be connected together at the top of the forming system, above the forms, with a top clamp 90.
Although the description above contains many specifications, these should not be construed as limiting the scope of the embodiments but as merely providing illustrations of some of several embodiments. Thus the scope of the embodiments should be determined by the appended claims and their legal equivalents, rather than by the examples given.
This application claims the benefit of the filing date of U.S. Provisional Application No. 61/852,433 filed Mar. 15, 2013 and incorporated herein by reference. This application claims the benefit of copending application Ser. No. 13/374,839 filed Jan. 17, 2012 claiming the benefit of the filing date of provisional application Nos. 61/461,437 filed Jan. 18, 2011 and 61/462,463 filed Feb. 3, 2011. All the above cited applications are incorporated herein by reference.
Number | Date | Country | |
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61852433 | Mar 2013 | US |