Field
The invention is in the field of Stay-In-Place decking forms for constructing concrete decking.
State of the Art
It is currently common practice in the construction of bridges, such as highway bridges, to erect a series of parallel bridge support girders in the form of I beams. Deck pans, such as corrugated metal pans, are installed between the parallel girders to close the space between the girders and provide a receiving form for concrete poured across the pans and girders to form a concrete bridge deck. The deck pans are supported between the girders by the horizontally extending surfaces of angle irons which extend along the longitudinal sides of the girders. The angle irons are attached by welding to the ends of straight flat straps which extend over the top surface of the girders. It is important to mount the deck pans at a desired height with respect to the upper surfaces of the girders so as to provide support for a desired thickness of the concrete deck and surface contour when concrete is poured into the pans and across the tops of the girders and smoothed to provide a smooth top concrete surface for the bridge. Since the deck pans are supported by the angle irons, it is important that the angle irons which support the deck pans at the desired height along the sides of the girders be properly secured by the straps at the desired height. Therefore, the vertical positioning of the angle irons along the sides of the girders is important. Once the girders are erected, the top surface of the girders are surveyed to determine the distance down from or up from the top of the girders to mount the angle irons. As the girders are surveyed, it is determined where the angle irons should be positioned with respect to the top surface of the girder to provide the desired top surface contour of the concrete deck. The determined position of the angle iron at a particular survey location along the length of the support girder is marked on the top surface of the support girder usually as either a “−” meaning “cut” or “+” meaning “fill” along with a measurement such as ½, meaning ½ inch, 1 meaning 1 inch, 2½ meaning 2½ inches, etc. with the “−” meaning to place the horizontal flange of the angle iron the indicated distance below the top of the top flange of the support girder, or the “+” meaning to place the horizontal flange of the angle iron the indicated amount above the top of the top flange of the support girder. The angle irons are then held in proper position by workers on the erected girders and are welded to the ends of the straps placed on the top of the top flange of the girders, again, by workers on the girders, while being held in place. This is a difficult and time consuming job. Further, it is important that when welding the angle irons to the straps on the girders, particularly with steel girders, that no welding arc between the angle irons or straps and the girder occur. In addition, it is important that no arcing occur between the welding equipment or wires to the welding equipment and the girders. Any arcing to a steel girder can damage the girder requiring expensive examination and repair of the girder. A further concern is that the welding produces toxic fumes. With workers holding the angle irons in proper position against the straps and other workers welding the ends of the straps to the angle irons, all in cramped conditions on top of the girder which is generally a significant height above the ground, it is difficult to keep workers from inhaling the toxic fumes.
It has been recognized that it would be advantageous to be able to more easily position and adjust the position of the deck pans when installing the deck pans between the bridge girders.
According to the invention, the angle irons used to support the deck pans are assembled to the straps, generally loosely assembled to the straps, and placed on the support girders prior to erection of the girders thereby requiring only adjustment of the vertical positioning of the angle irons with respect to the support girders and tightening of the angle irons to the straps when in position after erection of the support girders. The angle irons and straps can be assembled together on the girders with the girders on a floor or on the ground prior to erection, or the angle irons can be assembled to the straps to form an assembly of two parallel lengths of angle irons secured to opposite sides of the straps and spaced by the straps, which assembly can then be placed, as an assembly, on a support girder either before erection or after erection. The angle irons are adjustably secured to the straps so that with the support girders erected and the survey done so that the needed positioning of the angle irons with respect to the top of the top flange of the support girder is known, the angle irons can be easily positioned at the proper vertical position and then tightened to the straps. No welding of the angle irons to the straps on the erected support girders is necessary.
In one embodiment of the invention, the straps include substantially vertical end portions and one or the other or both of the strap end portions and angle irons are slotted. The angle iron is bolted to the strap with the slot or slots providing sliding adjustment between the two when the bolt is loose. The loose assembly of angle irons and straps are either assembled on top of the support girder or are assembled as a separate assembly and placed on top of the support girder. After the support girders are erected, surveyed, and marked, workers on top of the girder position the loosely attached angle irons in accordance with the survey markings and tighten the connection between the angle irons and the straps. When tightened, the angle iron is securely held to the strap and in adjusted vertical position with respect to the top of the top flange of the support girder on which the strap rests. When bolts are used to connect the angle irons to the straps, this merely involves tightening the bolts. This can be done with fewer workers and without welders on the top of the girders so is safer and less expensive.
Once the angle irons are properly positioned and tightened to the straps, the deck pans are placed on and supported by the extending horizontal side of the angle iron in normal prior art manner and concrete is poured over the deck pans and girders in normal prior art manner to produce the normal concrete deck.
Additional features and advantages of the invention will be apparent from the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate, by way of example, features of the invention; and, wherein:
Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended.
In the construction of concrete decks, such as concrete decks for highway bridges, structural supports, such as a plurality of parallel support girders 10,
Current (prior art) practice is to place a flat strap over the top surface of the top flange 20 of the erected girders 10 and to then weld the end of the flat strap to the vertical sides 22 of the angle iron 18 to secure the horizontally extending side 16 of the angle iron at the desired vertical height with respect to the top of the girder top flange 20. The system of the current invention does away with the welding of the end of the strap to the vertical side of the angle iron.
In the illustrated embodiment of the invention, the straps 30,
Also in the illustrated embodiment of the invention, the angle irons 18 are provided with slots 44,
With the present invention, the angle irons 18 can be installed on the support girders prior to erection of the support girders, and then, after erection and surveying, the vertical positions of the angle irons can be adjusted and the angle irons secured in the adjusted positions. Prior to the erection of the support girders, either in a shop location or at the erection location, while the support girders are on a floor or on the ground, workers can position the straps 30 on the top surface of the top flange 20 of the support girders 10, and can attach the angle irons 18 to the substantially vertical end portions 34 of the straps with bolts 50 passed through aligned slots 44 of the vertical sides 22 of the angle irons and slots 36 of the vertical portions 34 of the straps 30. The angle irons and straps can advantageously be loosely attached. For an intermediate slot 46,
While the angle iron assemblies will generally be installed on the support girders prior to erection, in some cases one or more lengths of angle iron may be left off the girder to provide space for attachment to a crane for lifting the girders into place during erection without damaging the angle iron assembly. In such case, an angle iron assembly can then be lifted onto the top of the support girder into the open length and attached to the ends of adjacent angle irons as describe.
As indicated, rather than building the straps of the invention by welding the angle pieces 38 to the flat straight portion 32 as shown in
When precast concrete girders are used, rather than a strap with a single flat intermediate portion which rests on and extends completely across the flat top surface of the girder as described up to this point, and which can be used with such precast girders in the manner described, separate straps can be provided for each side of the girder which are precast into the girder.
While spacing and sizes of components can vary, the straps should usually be placed about every eighteen to twenty four inches. The flanges on the support girder will usually be between about twelve to thirty six inches. Support girders will usually be about eight feet apart. The angle irons will usually be between about eight and ten feet in length.
The invention provides that the majority of the installation can be performed on the ground eliminating the fall potential inherent to working at heights. Also the bolted connections in place of welded connections eliminate the potential of inhaling toxic fumes generated by welding galvanized metal. The limited welding required can be performed in a shop under controlled conditions using ventilation systems. Further, the elimination of welding on the girders eliminates the potential for arc strikes on girders. Arc strikes on girders require specialized repairs and can potentially compromise the structural integrity of the girder. Further, the system of the invention allows the change of angle iron positions at any time during installation should this become necessary by merely loosening the bolts, adjusting the position of the angle iron, and retightening the bolts. Cost advantages are also provided because the system allows for shop assembly and installation by shop labor which is cheaper than field labor costs, certified welders are not required for field and top of girder assembly, and total man hours required for installation is reduced.
While the forgoing examples are illustrative of the principles of the present invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.
This is a Continuation-in-Part of copending application Ser. No. 14/525,203, entitled Apparatus for Supporting Stay-In-Place Metal Decking Forms, filed Oct. 27, 2014.
Number | Name | Date | Kind |
---|---|---|---|
3972169 | Sheppard, Jr. | Aug 1976 | A |
4982548 | Abbey | Jan 1991 | A |
6381793 | Doyle | May 2002 | B2 |
6463711 | Callies | Oct 2002 | B1 |
6568139 | Bot | May 2003 | B2 |
8234827 | Schroeder, Sr. | Aug 2012 | B1 |
9279244 | Miller | Mar 2016 | B1 |
20040129845 | Whale | Jul 2004 | A1 |
20160115683 | Miller | Apr 2016 | A1 |
Number | Date | Country | |
---|---|---|---|
20160115683 A1 | Apr 2016 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 14525203 | Oct 2014 | US |
Child | 14924440 | US |