Patent Application
20190063099
The present invention relates to construction methods for constructing a building, such as a residential structure, which has storm protection features and, more specifically, to a tornado resistant/proof residential dwelling structure.
A variety of storm resistant building/shelter systems are known in the prior art. These systems are intended to protect against such catastrophic events as hurricanes and tornados where potentially deadly destructive forces such as high wind velocities and high pressure differentials (as associated with tornados) and high wind and rain (as associated with hurricanes) exist.
The present invention could be applied to storm resistant buildings of a variety of types. However, the invention has particular applicability to tornado resistant/proof residential structures. Certain geographical areas are known to suffer from a high incidence of tornados. Generally, tornado-prone areas occur at middle latitudes where cold, dry air at a high altitude in the atmosphere meets warm, moist tropical air closer to the surface of the earth. For example, the central United States is prone to tornadoes because cold, dry air from the Rocky Mountains often meets moist, warm air from the southeastern United States. The damage to buildings, including residential dwellings, is extremely costly and, even worse, often includes loss of life. People are often injured or killed from total or partial collapse of the structure they are in, or from flying debris if they are not able to find adequate shelter in time. Tornados are capable of producing deadly air funnels with winds moving at 100 to 250 miles per hour or more. Tornadoes travel forward at an average speed of 35 miles per hour and their paths often cover as much as hundreds of yards in width. Because of their awesome destructive power, it is critical that human beings be able to find a strong protective shelter fast.
To reduce tornado injuries, people often find shelter in the basement of their homes. However, many people live in structures which have no basement. For people who live in a structure without a basement, other types of tornado protection shelters exist, often separate from the dwelling. However, these forms of tornado protection are limited because they require time for people to obtain shelter within the structure after they realize a tornado is approaching. This is difficult because of the unpredictable nature of tornadoes and the speed with which they form and travel. Thus, there is a need for a tornado resistant building design that encompasses an entire building structure, while at the same time providing a comfortable residence.
A brief survey of tornado resistant/proof structures includes the following: U.S. Pat. No. 1,706,496, is a very early patent on an “earthquake and tornado proof building” which, while probably not practical today, shows the long standing need for a solution to the problem at hand.
U.S. Pat. No. 4,126,972, describes a “tornado protection building”, one of the rooms of which has a tornado protection assembly extending across the top and sides of its interior, the building having a concrete slab under it, into which the protection assembly is anchored. The “storm proof room” is intended to resist forces in all directions exerted by a tornado, thereby protecting a first floor space which is part of a small, basement-less house.
U.S. Pat. No. 6,393,776, discloses a protective shelter for installation above and in the ground including a superstructure style frame, a composite wall structure for absorbing energy from forceful impacts, and a tub encased in a foundation. The tub provides a downward force such that the superstructure is not floated out of the excavation when the encasement is poured.
U.S. Pat. No. 7,921,604, describes an aluminum-foam structural housing unit that is stormproof, self-contained, and built to withstand natural disaster conditions resulting from hurricanes, tornadoes, earthquakes, and fire. The unit is buoyant during flooding conditions and lifts from the ground where it is guided by vertical poles to maintain a horizontal orientation. The unit also automatically disconnects from public utility systems as lifting occurs, and it then provides its inhabitants with self-contained sources of water, electrical energy, and sewage management.
U.S. Publication No. 2009/0013621, shows a tornado resistant structure which includes a base and a building structure positioned on the base. The building structure includes a plurality of deflection walls and reinforced corners and a plurality of skylights carried on a roof of the building structure.
The building structure includes an entrance and a drain positioned proximate to the entrance. The above discussion is not intended to be exhaustive, but merely illustrative of the types of structures and systems that have been envisioned in the prior art to address the problem of the tornado resistant/proof structure.
The more practical of the prior art structures are probably those which incorporate a “safe room” built within the traditional residential dwelling structure, as well as the known building systems where the entire external wall structure of a residential structure is built of reinforced concrete, or the like. A primary problem with the “safe room” approach is that everyone may not make it into the protective space in time. One disadvantage of the overall concrete “bunker” building approach is that such structures tend to be unattractive or down right unsightly and would not be allowed in many modern home subdivisions.
Thus, a need continues to exist for a tornado resistant/proof building, particularly a residential dwelling structure, which encompasses an entire building structure, not just the external sidewalls or an internal “safe room” and yet which has the appearance of a traditional, comfortable residence.
The present invention is directed toward materials and methods of constructing a tornado resistant/proof building structure and particularly toward a tornado proof residential dwelling structure. A main object of the invention is to provide such a structure which provides “whole house protection” for the occupants of the house from tornados or other dangerous weather events, while presenting an attractive external “facade” which looks the same for all practical purposes as any other typical house in a common housing subdivision.
The tornado resistant/proof residential housing unit of the invention is built to withstand natural disaster conditions resulting from such natural disasters as tornadoes, violent storms and fire. An internal concrete reinforced core layout gives the unit its great strength, as well as the versatility needed to face natural disaster conditions while providing absolute resistance to heavy winds such as those caused by a tornado. The unit has an attractive external facade which can assume virtually any appearance that the home buyer might desire, the internal reinforcing elements being entirely unobservable by the ordinary viewer.
In one preferred form, a tornado resistant/proof dwelling structure is provided which first includes a concrete slab upon which the remainder of the reinforced constituents of the structure will be erected. A series of interconnected reinforced concrete boxes are built upon the concrete slab, each having sidewalls, an initially open top, and a bottom which is enclosed by the concrete slab. A reinforced concrete ceiling is then erected which covers and encloses the top of the interconnected concrete boxes to form an internal reinforced concrete central core layout for the dwelling structure.
The internal reinforced concrete central core layout has internal walls and external walls which are all constructed from insulated concrete forms (ICF's) which have been filled with concrete and reinforcing rebar. The external walls of the internal reinforced concrete central core layout are provided with an external facade which mimics the exterior appearance of a typical subdivision home. The internal walls can also be finished out in conventional fashion. In the case of the dwelling structure of the invention, the internal reinforced concrete central core layout of the structure is capable of withstanding wind gusts on the order of 250 mph, or more, such as might be encountered in tornado conditions.
Additional objects, features and advantages will be apparent in the written description which follows.
The preferred version of the invention presented in the following written description and the various features and advantageous details thereof are explained more fully with reference to the non-limiting examples included and as detailed in the description which follows. Descriptions of well-known components and processes and manufacturing techniques are omitted so as to not unnecessarily obscure the principal features of the invention as described herein. The examples used in the description which follows are intended merely to facilitate an understanding of ways in which the invention may be practiced and to further enable those skilled in the art to practice the invention. Accordingly, the examples should not be construed as limiting the scope of the claimed invention.
As briefly mentioned, the present invention is directed toward materials and methods of constructing a tornado resistant/proof building structure and particularly toward a tornado proof residential dwelling structure. A main object of the invention is to provide such a structure which provides “whole house protection” for the occupants of the house from tornados or other dangerous weather events, while presenting an attractive external “facade” which looks the same for all practical purposes as any other similar house plan in a common neighborhood or subdivision.
Tornados are among the most violent known meteorological events. Each year, more than 2,000 tornadoes occur worldwide, with the vast majority occurring in the United States and Europe. In order to assess the intensity of these events, meteorologist Ted Fujita devised a method to estimate maximum winds within the storm based on damage caused; this became known as the Fujita scale. At the top end of the scale, which ranks from 0 to 5, are F5 tornadoes. These storms were estimated to have had winds between 260 mph (420 km/h) and 320 mph (510 km/h). In more recent years, engineers have designed a more comprehensive scale that takes into account some 28 different damage indicators; this became known as the Enhanced Fujita scale. According to this scale, winds in an EF5 tornado are estimated to be in excess of 200 mph (320 km/h), perhaps as much as 250 mph, or more. Since building structures are typically completely destroyed in these situations, the identification and assignment of scale between an EF4 tornado and an EF5 is often very difficult. The present invention has as one object to provide “whole house” protection to the dwelling inhabitants, even during the disaster type situation accompanying an EF4 or EF5 tornado.
There are a number of reasons that the construction techniques of the present invention provide advantages over other “safe room” or “storm shelter” designs known in the marketplace. For example, underground tornado shelters typically offer maximum tornado safety. However, many areas are not conducive to building underground “storm shelters” and many dwelling structures do not have basements. Also, the water table in some areas may practically prohibit building underground storm shelters or basements. In addition, underground construction costs are often greater than above-ground construction costs.
The only alternative to underground shelters is above-ground shelters or structures. While certain of the prior art building techniques have involved solid concrete external walls, these structures tended to be unattractive and would not be allowed in many modern subdivisions due to building code issues, homeowner covenants, and the like. Typical above-ground dwelling structures constructed of traditional wood, brick and mortar are vulnerable to tornadoes due to their high wind resistance and low structural strength. None of these traditionally constructed dwelling structures would withstand the wind force present in an EF4 or EF5 tornado.
Other attempts to address this problem have included solutions which involved building designs or unique or unusual appearance. For example, with regard to wind resistance in above-ground structures, a spherical dome would be expected to have the lowest all-around wind resistance. However, curved surfaces are not as easy to work with or manufacture as are planar surfaces. The appearance of these structures, like solid concrete buildings, would not lend their designs to being incorporated in the typical homeowner subdivision.
first pouring a concrete slab;
thereafter, erecting a series of interconnected reinforced concrete boxes upon the concrete slab, each having sidewalls, an initially open top, and a bottom which is enclosed by the concrete slab;
installing a reinforced concrete ceiling which covers and encloses the top of the interconnected concrete boxes to form an internal reinforced concrete central core layout for the dwelling structure;
wherein the internal reinforced concrete central core layout has internal walls and external walls which are all constructed from insulated concrete forms which have been filled with concrete and reinforcing rebar; and
erecting an external facade about the external walls of the internal reinforced concrete central core layout, thereby forming a dwelling structure exterior which mimics the exterior appearance of a typical subdivision home.
In more detail, the stages of construction for the tornado resistant/proof home of the invention include the following phases:
Clear lot site, prepare ground for concrete slab, dig footers, install perimeter forms, install all foundation and slab re-bars per structural design drawings, all electrical and plumbing rough in work, pour 120 cubic yards of Readi-mix™ concrete with pump truck and finish.
Layout all exterior walls for ICF Block installation, set first two courses with horizontal re-bars, level and square entire house, continue setting ICF Blocks up to 7th course to 10′ 6″ height, lay out and build all structural interior walls per design drawings, set all window and door bucks, all rough-in for plumbing and electrical inside walls installed, fill all walls with 81 cubic yards of concrete with pump truck.
Set all shoring and bracing for pouring 6″ concrete ceiling lid per design drawings (to close off top of the structural design engineered designed box), set all jacks, frames, I-beams and ¾″ HDO plywood at height of 10′ 6″ throughout house, install perimeter edge, install all re-bar and set all exterior windows and doors.rs per design drawings, pour 54 cubic yards of concrete with pump truck and finish, rough in by all subs before pouring.
Construct 2×6 structural roof framing per design drawings, install roof vapor barrier and 30 year asphalt shingles per specs.
Spray in all roof rafters R-38 foam insulation per specs.
Frame all other interior walls and drop ceilings, install dry all and finish, set all interior doors, all interior painting and staining per plans.
All exterior brick work and stone work per plans, pour concrete driveway and walks, finish landscaping and irrigation system, install garage door.
Install all finish floor coverings and millwork and finish plumbing, electrical, and HVAC.
The construction projects of the invention instead use a self-interlocking block system that is mortarless, so that an unskilled laborer can easily and quickly build an above ground or below grade wall or foundation wall. The preferred mortarless system is known in the industry as the insulated concrete form or “ICF” system. One commercially available straight ICF block, known as the Fox™ ICF Straight Block, is described as follows:
The Straight Block typically makes up 85% of the ICF wall assembly on most residential & commercial jobs. This block has six (6) strong full length injection molded plastic ties made from Polypropylene (PP) regrind resin. These ties secure the two pieces of 1.5 pcf density modified Expanded Polystyrene (EPS) foam together that makes up each block type. The blocks are stacked tightly together and inter-locked end to end to the desired wall length. Once a single layer or course of ICF blocks is installed, horizontal reinforcing steel bars are inter-locked securely together in the ties of the blocks, then another course of Straight Blocks are placed firmly on top as the wall is built. To improve construction wall strength during installation, each course of blocks should have their end joint connections staggered in a running bond method from the course adjacent to it. Typical dimensions are as follows:
ICF blocks are also commercially available in a variety of other forms including angle blocks, corner blocks, T-blocks, tapered blocks, ledge blocks, radius blocks and curb blocks.
A reinforced concrete ceiling (generally at 33 in
As will be appreciated from
The completed internal reinforced concrete central core layout thus has internal and external walls which are constructed using the ICF building blocks previously described which are filled with concrete and reinforcing rebar, with the rebar running vertically between the concrete slab and the concrete ceiling. The walls of the central core layout will typically be a minimum of 6 inch thick concrete.
An external facade is then erected so as to cover the central core layout so that the external facade mimics the exterior appearance of a typical subdivision home, for example, such as the nearby homes in the subdivision being constructed by traditional brick and mortar principles. As previously mentioned,
An invention has been provided with several advantages. The construction techniques of the invention provide a tornado resistant/proof building, which can be a residential dwelling, which is capable of withstanding high winds on the order of 250 mph. The reinforced central core provides “whole house protection” for the inhabitants. It is not necessary that the inhabitants locate and run to a storm shelter or “safe room” within or adjacent to the structure. While the techniques of the invention provide unique safety considerations, the external appearance of the dwelling structure is indistinguishable from adjacent houses in the same neighborhood. The reinforced structures of the invention do not exhibit the “concrete cast block” external appearance of prior art “storm proof” housing designs, such as the hurricane resistant structures build along the coastal regions of the country. Because of the very nature of the ICF block construction, the homes of the invention are necessarily very energy efficient, providing long term cost savings for the inhabitants.
While the invention has been shown in only one of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit thereof.
