US20010020559A1

US20010020559A1 - Equipment support systems

Info

Publication number: US20010020559A1
Application number: US09/772,058
Authority: US
Inventors: Ronald McCracken
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-09-02
Filing date: 2001-01-29
Publication date: 2001-09-13

Abstract

Equipment support systems and modular platforms provide an equipment support portion with lateral walkways and work areas. The platforms have a skeletal frame that supports a plurality of grates to form the work area. The frame of the platforms also has a number of support legs with circular bases at their lower ends to rest upon the roof or other support surface. The circular bases distribute the load of the supported equipment evenly upon the roof so that specific spots are not overloaded. Outriggers may be removably added to the platform to increase the dimensions of the platform thereby making the platform and supported equipment less prone to overturning from wind loading. Methods are described for providing a support platform designed to resist a specific design wind load. In some preferred embodiments, one or more of the support legs of the platforms are adjustable in length, to allow portions of the platform to be adjusted for differential settlement of the roof.

Description

This is a continuation of patent application Ser. No. 09/388,695 filed Sep. 2, 1999. [0001]

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to devices and methods used for supporting equipment on the rooftops of buildings or in similar locations. In particular aspects, the invention is directed to support systems for telecommunications equipment, heating and cooling equipment and the like.

2. Description of the Related Art

Modem commercial buildings normally mount most of their auxiliary equipment on the roof of the building. This auxiliary equipment includes telecommunications equipment, antennas, waveguides, ice bridges, heating and cooling equipment, ductwork and piping. Currently, telecommunications enclosures and materials are being installed on the roofs of new buildings as well as being retrofitted onto older buildings. In some instances, this equipment is mounted on the ground or another support surface.

A number of commercially-available support systems are currently used or known to mount the auxiliary equipment on roofs or other locations. Most often, however, make-shift supports are created out of pieces of angle iron that are secured by screws or other fasteners to the rooftop. A problem with conventional support systems is that the fasteners damage the rooftop. Further, as a building roof is exposed over time to rain, snow, wind and extreme temperature variations, the support systems tend to damage the roof even more as the hard and sharp edges of angle iron pieces or wood cut into the rooftop.

A further drawback is that currently known support systems are not easily installed on uneven roofs or roofs where the elements have caused differential settlement. When settlement occurs, the support platform can become unstable, and weight from the supported equipment can become concentrated in a few areas. To address the problem, shims can be fabricated on-site to shore up a portion of the support system and level it out. However, the shims are often made of cut pieces of wood, such as plywood or lumber. These cut pieces typically have relatively sharp corners and edges that can also cut into the roofing material over time, thus damaging the roof and creating the potential for leaks.

Even without differential settlement, conventional support systems do not always distribute the load of the supported equipment evenly across the rooftop. Instead, the load may be concentrated onto just a few support members, thereby resulting in eventual failure of the rooftop in those areas.

A further drawback of conventional, particularly makeshift, rooftop support systems is that they are typically not designed to resist specific wind loads. Those systems that are constructed to resist design wind loads do so by securing the support system to the rooftop or to the structure of the building. If the support system is under-designed, the supported equipment may blow over or become torn loose from its support system during high winds. As over-designed support system may be costly and excessively heavy.

It would be an improvement to have systems and methods that address the problems of the prior art.

SUMMARY OF THE INVENTION

The present invention provides improved equipment support systems. In described embodiments, modular platforms are constructed that provide an equipment support portion with lateral walkways and work areas. The platforms have a skeletal frame that supports a plurality of grates to form the work area. The frame of the platforms also has a number of support legs with circular bases at their lower ends to rest upon the roof or other support surface. The circular bases distribute the load of the supported equipment evenly upon the roof so that specific spots are not overloaded. Outriggers may be removably added to the platform to increase the dimensions of the platform thereby making the platform and supported equipment less prone to overturning from wind loading. Methods are described for providing a support platform designed to resist a specific design wind load.

In some preferred embodiments, one or more of the support legs of the platforms are adjustable in length, to allow portions of the platform to be adjusted for differential settlement of the roof.

The support platforms of the present invention provide a number of additional operational advantages not found in conventional systems. These include the presence of walkway and work areas adjacent the equipment support section of the platform, access space beneath the platform and the rooftop for the running of cables, piping or the like, and drainage and air flow through the platform.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an exemplary support platform constructed in accordance with the present invention. [0014]
FIGS. 2 and 3 are side and isometric views, respectively, of the platform shown in FIG. 1. [0015]
FIG. 4 is a partially exploded view of the platform shown in FIGS. [0016] 1-3.
FIG. 5 illustrates the platform of FIGS. [0017] 1-4 having structures supported thereupon.
FIGS. 6 and 7 are plan and side views, respectively, of an exemplary support platform with modular outrigger portions added. [0018]
FIGS. 8 and 9 illustrate an exemplary adjustable leg structure for use with platforms in accordance with the present invention. [0019]
FIG. 10 is a block diagram illustrating the effect of weight forces upon an exemplary platform and supported load. [0020]
FIG. 11 is a block diagram illustrating potential rotational motion of the platform and supported load in response to wind loading. [0021]
FIG. 12 illustrates the relationship between the height and weight of the platform and supported load and the length of overhang needed to resist an overturning moment.[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. [0023] 1-5, illustrate an exemplary support platform 10 constructed in accordance with the present invention. The platform 10 is constructed of modular components that can be readily assembled and disassembled. The platform 10 has a central equipment support section 12 and a laterally-located areas 14 that serve as walkways and allow access to equipment supported on the equipment support section 12. As FIG. 2 shows, the platform 10 is placed on a supporting surface 16 without being affixed to the supporting surface 16 by fasteners. The typical supporting surface 16 is the rooftop of a building.
The [0024] platform 10 includes a skeletal supporting frame that is formed of metal frame members and tubular struts interconnected by bolt-and-nut assemblies or other connectors. The equipment support section 12 is formed by frame members 18 that are preferably sections of angle iron. It can be seen that the frame members 18 form a base to which equipment such as a telecommunications building can be affixed and supported atop. The base formed by the frame members 18 also defines openings 19 through which electrical cabling, piping or the like (21 in FIG. 5) can be disposed and interconnected with the supported equipment.
[0025] Brackets 20, visible in FIG. 5, extend from the frame members 18 so that the lateral walkway areas 14 can be reversably attached to the central support section 12. The lateral walkway areas 14 include a number of horizontally-disposed supporting struts 22 that interconnect to the brackets 20. The struts 22 are preferably tubular metal pieces, or box-beams, that have a square or rectangular cross-section. Metallic grates 24 are placed atop the supporting struts 22 and are affixed to them using clips of a type known in the art for affixing grating to a support member. The grates 24 are preferably rigid, metallic grids that define rectangular gaps 26 that permit drainage and air flow through the grate 24. Drainage and airflow is particularly important since the equipment mounted upon the equipment support portion 12 is often telecommunications equipment or heating and cooling equipment that benefits from improved air circulation around the equipment and the prevention of flooding. The grids 24 are preferably constructed of a durable steel, iron or aluminum that is sufficiently sturdy to support the loads of the equipment to be mounted thereupon. The presence of the grids 24 allows airflow through the work areas 14 and around the supported equipment.
A plurality of vertically-[0026] disposed support legs 28 extend downwardly from the equipment support portion 12 and the work areas 14. The legs 28 may be simply box-beam sections or adjustable assemblies of the type which will be described shortly. The lower end of each leg 28 is seated within a substantially circular, load-distributing support base 30. Support bases 30 are preferably of the type described in U.S. Pat. No. 5,816,554 entitled “Equipment Support Base” by Ronald G. McCracken, which is herein incorporated by reference. The bases 30 are lightweight and effectively distribute weight over the entire footprint of the base 30 so as to avoid unnecessarily localized stresses in the roof surface 16. It is pointed out that neither the bases 30 nor other portions of the support platform 10 need to be secured to the roof 16 or to the structure of the building, thereby making installation of the platform 10 inexpensive and quick. Further, the structure of the rooftop 16 is not damaged by the use of fasteners. Although not shown, it is preferred that in rooftop applications, a slip sheet formed of roofing material or another suitable, durable material be placed between the base 30 and the roof surface 16. The slip sheet will tend to hold the base in place and resist movement of the slip sheet with respect to the roof surface 16.
It can be seen that, when constructed, the [0027] platform 10 provides a work and access area 14 proximate the equipment support portion 12. Also, the fact that the platform 10 is raised above the supporting surface 16 of the roof provides space for the running of cabling, piping and the like 21 beneath the platform 10. The cabling and piping can then be disposed through the openings 19 of the equipment support portion 12 and interconnected with the supported equipment 32. As a result, needed cabling and piping is maintained out of the way of personnel located on the work and access areas 14 minimizing the chances that it will be inadvertently damaged.
One or more support brackets [0028] 33 (one shown in FIG. 5) extend between and are affixed to adjacent bases 30 beneath the equipment support portion 12 and are used to support the piping, cabling and the like 21 above the support surface 16. The support brackets 30 are preferably affixed to the bases 30 using lengths of all-thread that are threaded into matching recesses on the bases 30. The construction and operation of brackets 33 is described in further detail in U.S. Pat. No. 5,816,554. It is also noted that other suitable support arrangements for pipes are described therein.
FIGS. 6 and 7 depict an [0029] exemplary support platform 50 that has modular outrigger portions 52 attached that increase the resistance of the platform to wind loading against the sides of the equipment. The platform 50 is constructed in a similar manner as the platform 10 described earlier except that a number of struts 18 have been removed from the equipment support section 12. The outrigger portions 52 provide further lateral support and stability to the platform 50. If desired or needed, additional outrigger portions can be modularly affixed to one or more sides of the platform 50 in order to increase the resistance of the platform to overturning due to wind loads upon a mounted structure.
It is further pointed out that differing sizes of modular platforms can be constructed to meet different wind resistance requirements. To do this, a design wind load is first selected or determined. The design wind load is a preselected wind velocity that the platform and supported equipment must resist so that moments imposed upon the structure do not result in overturning. The design wind load may vary according to geographical area and/or be based upon subjective factors. Most commonly, the design wind load is established by a local government or municipality. For example, a city might establish a building code that requires that equipment mounted on rooftops to withstand wind speeds of 90 MPH. [0030]
The effective wind exposure area and the weight of the supported equipment are then determined. The effective wind exposure area of the supported equipment is related to the height of the supported [0031] structures 32. The required length, or overhang, of the platform from its center point to a side can then be determined.
Referring now to FIGS. 10, 11 and [0032] 12, calculations used to determine a required amount of overhang for a platform are illustrated. FIG. 10 is a simplified block diagram depicting an exemplary platform 80, which is of the type described previously for platforms 10 or 50. The platform 80 has a load 82 disposed thereupon that is representative of the weighted load provided by supported equipment, such as equipment 32. The total weight R_T(illustrated by the downward arrow in FIG. 10 is the combined weight of the load 82 and the platform 80. Since the critical calculations for moments is about the corners 84, 86, 88 and 90 of the platform 80, the total weight R_Twill be considered to be distributed evenly at each of the corners of the platform 80 and transmitted to the supporting surface 16 (not shown in FIG. 10) at those points. The forces R₁, R₂, R₃and R₄are illustrative of these weight forces.
As FIG. 11 illustrates, the [0033] platform 80 and supported load 82 can rotate in three directions. These three directions are illustrated, respectively, by (a) the lines 92 between corners 84 and 86 or corners 88 and 90; (b) the lines 94 between corners 84 and 90 or corners 86 and 88; and (c) a vertical axis 96. In other words, the platform 80 could either rotate upon the support surface 16 around vertical axis 96 or else overturn along any of its four sides. It is the latter, overturning type rotation that is particularly of concern here.
When a wind load (shown in FIGS. 11 and 12 as F[0034] _W), is applied to the load 82 and platform 80, the load generally acts upon them in a direction that is parallel to the supporting surface 16. The wind load F_Wnormally acts perpendicular to the largest frontal area of the equipment load 82. For the purposes of conservative estimation, it is presumed that the wind load F_Wacts at the upper end 97 of the load 82, thereby inducing a maximum turning moment M (98 in FIG. 12) about the opposite edge 100 of the platform 80. The moment M is defined by the following equation: $M = (F_{W} \times H) - (R_{T} \times Length of Overhang)$
where H is the height of, or vertical distance to, the [0035] upper end 97 of the load 82 from the support surface 16, and the Length of Overhang is the distance from a central point of the platform 80 to the edge 98 of the platform 80.
When the moment calculated by this equation is a negative number, the [0036] platform 80 and load 82 will remain stable against the force of the wind F_W. Conversely, if the moment calculated is positive, the platform 80 and 82 will likely overturn. It can be seen that as the Length of Overhang is increased, the value of M will decrease, thus increasing the stability of the platform 80.
Given the relationship above, the equation can be solved for the required length of overhang using the following equation: [0037] $L = [(F_{W} \times H) - M] / R_{T}$
by inserting a positive number for the moment M. This type of analysis for overturning moments M and the required Length of Overhang should be performed for each of the four faces of the [0038] platform 80 and load 82.
Once the required Lengths of Overhang have been determined, a proper sized platform can be constructed on a roof surface, or other support surface, by adding enough outriggers to each side of a platform to ensure that the platform will not overturn in any direction. As the platform is disposed on the support surface in this manner, the [0039] legs 28 of the platform are disposed within the load-distributing bases 30. The supported equipment 32 is then secured to the equipment support portion 12.
When constructed, platforms of the present invention preferably provide a convenient work and access area that is laterally located to, and may surround, the [0040] equipment 32. Also, the fact that the platforms are raised above the surface 16 of the roof provides space for the running of cabling and the like beneath the platforms.
The modular nature of the support system permits suitable platforms to be assembled or disassembled quickly and easily. Further, the modular nature of the support system permits suitable platforms of various sizes and configurations to be packaged and shipped as needed. [0041]
Platforms constructed in accordance with the present invention can be provided with adjustable legs when required or desired for uneven rooftop surfaces. Referring to FIGS. 8 and 9, an exemplary [0042] adjustable assembly 60 is shown that may be used as one or more of the legs 28 for the platforms. Lower box section 62 is shaped and sized to fit within the central opening of a support base 30. The adjustable leg assembly 60 further includes a strut 64 with a closed bottom end 66. Although not shown, it will be understood that the upper end of the strut 64 is affixed to a portion of a platform. The bottom end 66 has a threaded hole (not visible) through which a threaded shank 68 is disposed. The threaded shank 68 is fixedly mounted to a platform 70 atop the box section 62. By rotating the box section 62 and platform 70, the threaded shank 68 is screwed into or out of the bottom end 66 of the strut thereby moving the box section 62 closer to (as in FIG. 9) or further away from (FIG. 8) the strut 64. In this way, the length of the leg assembly 64 is adjusted. A nut 72 is retained on the threaded shank 68 and may be rotated downward to be brought into contact with the bottom end 66 after adjustment to lock the adjustable assembly 66 at the length chosen. It is noted that a portion of the strut 64 is cutaway (at 74) to provide access to the nut 72.
Adjustment of the length of one or more [0043] adjustable leg assemblies 60 may be necessary to account for settlement of portions of the roof surface 16. Also, all of the legs 28 of a platform may be adjustable assemblies 60, thereby allowing the height of the entire platform with respect to the roof 16 to be adjusted.
While the invention has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes within departing from the scope of the invention. [0044]

Claims

What is claimed is:

1. An equipment support platform for supporting equipment on a rooftop and the like, comprising:

an equipment support portion having a structural base for the affixation of equipment and an opening defined within the base through which cabling, piping and the like may be disposed; and

a reversably connectable work area portion surrounding the equipment support portion.

2. The equipment support platform of

claim 1

further comprising a reversably connectable outrigger portion that can be connected to the platform to increase the resistance of the platform to wind loading.

3. The equipment support platform of

claim 1

wherein the work area portion further comprises a grate that permits airflow and drainage therethrough.

4. The equipment support platform of

claim 1

further comprising an leg that is adjustable in length to selectively change the height of a portion of the platform above a supporting surface.

5. The equipment support platform of

claim 4

wherein the adjustable leg further comprises a securing member for locking the leg at a selected length.

6. The equipment support platform of

claim 1

further comprising a plurality of leg members that support the platform above a support surface, the leg members each having a substantially circular base member at its lower end.

7. A support system for use in supporting telecommunications equipment and the like on rooftops or other locations, the system comprising an equipment support platform having:

a) an equipment support portion with a central area defined therein; and

b) at least one laterally located platform affixed to the equipment support portion to resist turning moments induced by a design wind load F_Wupon equipment supported by the support portion, the platforms providing a length L as measured from the central area of the support portion being related to the design wind load F_W.

8. The support system of

claim 7

further comprising an additional platform that can be laterally affixed to the equipment support platform to increase resistance of the platform to turning moments.

9. The support system of

claim 7

wherein the length is related to the design wind load by the following equation:

L = [(F_{W} \times H) - M] / R_{T}

where H is the height of equipment supported, M is a positive number indicative of a turning moment induced by the design wind load, and R_Tis the total weight of the platform and equipment supported by the platform.

10. The support system of

claim 7

further comprising an adjustable leg assembly for selectively changing the height of portions of the platform above a supporting surface.

11. The support system of

claim 10

wherein the adjustable leg assembly further comprises a securing member for locking the portions of the platform at a selected height.

12. The support system of

claim 10

further comprising a load-distributing support base within which the leg assembly is seated.

13. The support system of

claim 7

wherein portions of the laterally located platform comprise apertured grates that permit drainage and airflow therethrough.

14. A method of providing a stable support platform for telecommunications equipment and the like, comprising:

a) establishing a design wind load that a platform and supported equipment must withstand against overturning;

b) determining the height and weight for a load to be supported upon a central portion of the support platform; and

c) using said height and weight, determining a required length of overhang for the platform.

15. The method of

claim 14

wherein the operation of determining a required length of overhang further comprises selective a positive value for an overturning moment.

16. The method of

claim 14

wherein the operation of determining a required length of overhang further comprises relating the length of overhang to the design wind load by the following equation:

L = [(F_{W} \times H) - M] / R_{T}

17. The method of

claim 14

further comprising the operation of disposing the platform on a support surface.

18. The method of

claim 17

further comprising the operation of mounting a load to be supported upon a central portion of the support platform.

19. The method of

claim 17

wherein the support surface comprises a roof surface.

20. The method of

claim 17

wherein the operation of disposing the platform upon a support surface further comprises the operation of securing legs of the platform within load-distributing bases.