FIELD OF THE INVENTION

The present invention relates to the construction of basement structure, more specifically, basement structure using prefabricated wall units.

BACKGROUND OF THE INVENTION

Traditional basement construction involves casting the structure on site. In some instances it involves the construction of forms in the shape of the vertical basement walls. Concrete is then poured into the forms, and the forms are subsequently removed after the concrete hardens. In other instances, the construction involves laying block courses to make vertical walls, and the concrete is then poured into the vertical walls. Such methods are generally regarded as time-consuming, labor intensive and expensive. In colder countries, such methods are only suitable in a relatively short period of the time during the year.

More recently, prefabricated wall units such as made of concrete have been used in a variety of building applications. US Patent No. 5,199,233 showing prefabricated basement having a number of underground concrete block units. However, the size of the concrete block may cause difficulties or higher costs during transportation.

US Patent No. 5,493,838 shows a method of constructing a building basement from prefabricated concrete units. Use of prefabricated wall panel units in basement structure, however, often involves the difficulty of adjusting accurate positioning including horizontal alignment of the basement structure, in particular, to the desired elevation. Problems due to the lack of accuracy arise when further structures such as a house are mounted on the basement. In some instances, the load allowed on the structure may be limited due the the footing method used to stabilize prefabricated wall units.

The abovementioned methods most likely additionally require a thorough preparation of a substantially flat footing surface area onto which the prefabricated wall is mounted on. Accordingly, there is still a need to minimize the required amount of work in preparing a building foundation footing surface.

Many or most basement structures initially have had the aim of being fundament and resting structure for the house builds thereon. There is a need to provide a basement structure with a good footing connection to the earth and form an accurate and level platform for the house to be erected thereon.

On sites where the earth has uneven consistency and includes, for example, soft spots, deeper excavation of the earth may be required to pass the soft spot to reach a better soil; alternatively, the soft soil may have to be replaced with lean fill. The adaptation to the earth often demand additional work, and hence, additional cost and labor. There is accordingly a need to provide a less labor intensive method which offers a shorter construction time.

SUMMARY OF THE INVENTION

The present invention provides a concrete basement construction using prefabricated concrete wall units, and the method thereof. The wall units are arranged and levelled prior to the casting of a footing structure.

According to the present invention a method of footing prefabricated wall unit for constructing a concrete basement is also provided. After excavating earth from an intended building site and preparing the footing surface area, thereby defining an outline of a building, at least two support units are arranged on the footing surface. Then, a first prefabricated wall unit is mounted onto the support units and adjusted in an upright position and horizontal alignment.

Optionally, height adjustment units may be placed on the support units underneath the wall unit to achieve the desired height. More than one height adjustment units may be used in order to obtain correct position of the wall unit.

Next, form a mould by placing moulding plates longitudinally along the lower part of the wall units enclosing the support units and extending above the bottom edge of the wall units. Thereafter, fill the mould with a filling and binding material, preferably concrete, and finally allow the filling and binding material to harden. With this process a footing structure can be made, bonding the wall unit and the support unit together to provide a stable and even support to the structure which will be mounted atop. The moulding plates may optionally be removed and reused after the hardening of the filling and binding material. An absolute level footing surface having exactly the required depth is not necessary prior to the construction of the basement structure. Other objects, advantages, and features of the present invention will become apparent from a consideration of the drawings and descriptions below.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the invention will become more apparent from the following description, in which reference is made to the appended drawings, wherein:

Fig. 1 is a section view taken along section lines A-A of FIG. 7. Fig. 2 is a section view taken along section lines B-B of FIG. 7.

Fig. 3 is section view taken along section lines A-A of FIG. 7.

Fig. 4 is section view taken along section lines B-B of FIG. 7.

Fig. 5 is a perspective view of a wall unit.

Figure 6 show a sectional cut C-C from fig 5. Fig. 7 is a side view of wall unit.

Fig. 8 is a side view of the basement structure supporting a housing structure.

Fig. 9 is a perspective view of erection of basement wall units.

Fig. 10 is perspective view of a basement structure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As defined herein, a prefabricated wall unit, or simply, wall unit, generally refers to a wall panel which is prefabricated in the factory and then brought to the construction site.

The preferred embodiment, a method of constructing and erecting a prefabricated basement structure will be described with reference to Fig. 1 through 10.

There will first be described the components which are used as part of the method. Referring to Fig 1 and 2 support units 2 are used. Each of the support units are place on the footing surface 1 of the excavated ground. The footing surface may be the same or deeper than the required depth. It should be noted that the support units 2 is preferably precasted, although they may be formed on the site. The units may be of any material applicable, such as steel or concrete. Each wall unit is preferably mounted at least two such support units 2 suitably placed to provide a stable support. One support units may be shared by two wall unit. In this case it is placed to support the ends of the wall unit. This is favourably when the wall units forms together corners. However, in normal end- to-end joining this may also be employed.

Before placing the wall unit 3 on the support units one or more height adjustment units 11 are arranged in order to allow the wall unit 3 to sit horizontally correctly on the two support units. The wall unit in most situations should have a level top surface. When necessary _/ the upper part of the wall unit may be trimmed to its final height. Two moulding plates 4 are arranged to laterally, one on each side of the support unit. The moulding plates preferably have a height sufficiently extending above the lower part of the wall unit 3 so when the filling and binding material, preferably concrete, is filled, the material may encose the lower part of the wall unit to provide a stronger bond. The support unit itself may serve as the end-barrier for the filling and binding material. However, when needed, end moulding plates defining the front and back end of the mould may also be placed.

In accordance with the present invention, the support unit comprises a parallel, flat top and bottom surfaces. The width of the support unit is preferably wider than the prefabricated wall units. Preferrably, the filled and binding material provides a stable support for the wall at its entire length. However, if desired, the foot structures do not have to continuous.

Use of moulding plates provides the flexibility of varying the footing dimension. On footing surface area where there is change in elevation, for example, in a typical house situation where the house requires a proper basement structure and the garage requires on a shorter frost wall, the distance between the moulding plates may be varied to corresponde to the required support. A variance in soil condition may also be dealth with. In situations where the the site contains spots where the soil bearing capacity is low, a different width of the footing structure may be required. Additionally, on corners or spots where the prefabricated wall unit join each other, a moulding plate provides the possibility to strengthen the joint with footing structure of a desired shape, size, and height.

The moulding plate may be left in the ground, when, for example, the stripping of mould is undesired. Alternatively, the moulding plates can be removed and reused.

A miscentered prefabricated wall unit on the support unit may be corrected by placing the moulding plates in a way so the footing structure thereafter formed has a desired formation.

By varing the size and position of the moulding plate, the final footing may come in various forms, which provides the advantage of being capable of adapting to the soil and condition on site. In addition, the usage of filling and binding material can be limited to the extent necessary, thus reducing the cost.

Figure 3 and 4 show the same arrangement as in figure 1 and 2 though without the moulding plates 4.

Figure 5 shows a wall unit 3, arranged onto a pair of support units 2. The wall unit 3 is supported to avoid falling by a pair of support shores or similar 15. Additionally, a pair of moulding plates 4 is arranged parallel to the wall unit and encloses the support units, while the extending vertically above the height of the lower side of the wall unit 3.

Figure 6 shows a sectional cut A-A from fig 5.

Figure 7 shows side view of a wall unit 3 arranged onto support units 2 resting on the surface area 1. In between the bottom of the wall and the support units 2 a height adjustment unit 11 is placed in order to adjust the horizontal alignment of the wall. The height adjustment unit may be in the form of flat plate, thereby allowing gradual adjustment of the height, where each plate may have a thickness of at least 1 mm.The height adjustment material is preferably made of steel or other suitable material.

Figure 8 shows how a housing structure is mounted on the basement structure. Figure 9 shows perspective view of erection of the wall units 3. Each unit is lifted, for example, with a crane 18, and placed onto the support units. Height adjustment units of appropriate thickness are preferably placed on the support unit before the final mounting of the wall units. A mould is then formed which enclose the support units and extend above the lower edge of the wall. Then, a filling and binding material 7, preferably concrete, is poured into the mould to bind the wall units securely to the support units.

Finally figure 10 show a basement structure 17 with plurality of wall units 3 resting on a number of support units 2. Some support units 8 supports more than one wall units.

Unlike other conventional methods, the present invention does not have to involve the use of a jack cynlinder, which is inserted beneath the prefabricated wall units to achieve the desired height. The removal of the jack cylinder often requires additional work in footing casting, disadvantageously prolonging the construction process.

The basement structures described herein are not limited to any kind of basements, including a traditional living or woking basement such as daylight basement, look-out basement, walk-up basement. Other types of basements, such as crawling space, cellars, and other fundaments also fall within the scope of this present invention.

It will be apparent to one skilled in the art that modifications may be made to the illustrated embodiment without departing from the spirit and scope of the invention.