GB2216153A - Permanent shuttered in situ beam foundation system - Google Patents

Abstract

A permanent shuttered in situ beam foundation system for house and similar foundations comprises standard components preformed in a factory in glass reinforced plastic or plastic extrusions. [They are lightweight and may be positioned by operatives of average skill.] Which are positioned on the heads of piles, apertures may be cut to allow the pile heads to penetrate the shuttering. Piles are installed and there is sufficient allowance in the width of the shuttered sections to allow for site driving misalignments. Reinforcing steel may be placed in the shuttering. Components can be cut by hand-saws. The tool to form the pile aperture is manufactured from a section of the pile casing. The system is easily adapted to cater for swelling soils by laying in low density polystyrene or clayboard beneath the components. Steel arrangement depends on loadings, taking account of minimum cover to steel because of protection by shuttering and considering reduction in steel area utilizing tensile strength of the shutter material. <IMAGE>

Description

PERMANENT SHUTTERED IN SITU BEAM FOUNDATION SYSTEM.

This invention relates to a permanent shuttered in situ beam foundation system to be used in conjunction with "mini" piles for domestic and other structures with relatively light loadings.

"Mini"piling systems have been the subject of B.R.E.Digest No. 313. They are quickly and easily installed on sites and can provide safe working loads compatible with domestic and other structures.

"Mini" piling systems do not require large piling rigs and can be installed on site on a high volume basis using the minimum of mechanical -equipment.

A permanent shuttered in situ beam foundation system has therefore been devised to allow the construction of in situ reinforced concrete beams capable of high volume installation by builders and estate developers.

Attention has been given to the requirement to minimize site handling by mechanical means and the entire system is capable of utilization by civil engineering/building operatives with average skill. Ready-mixed concrete pumped from delivery bowsers will allow the placing of concrete to several housing units at once.

As land for building becomes more scarce, development sites, which would not have been considered years ago because of poor ground conditions, are utilized. In this situation the use of piled foundations with a cost effective beam system becomes viable.

The essential technical.feaures comprise 1. Prefabricated trough shuttering in glass reinforced plastic or plastic extrusions produced on a volume basis, together with 4 no. basic component junctions as illustrated in drawings PS1, PS2, PS4, PS5,PS6 and PS7.

2. The steel reinforcement cages are prefabricated off site to a standard design and increases in loadings for special situations may be provided by utilizing additional reinforcing bars laid in and fixed on site. Similarly, junctions between beams may be provided by reinforcing bars appropriately laid in and fixed on site.

In order to reduce to a minimum the amount of reinforcing steel required to provide tensile and compressive reinforcement in the beams it is the intention that the permanent trough shuttering will be developed to provide a degree of tensile strength.

3. At pile positions the aperture is cut with a special cutter fabricated from the steel casing utilized for the piles as illustrated in drawing PS3.

4. The system is designed to provide (a) A minimum of mechanical handling.

(b) The capability of high volume installation.

(c) An ideal foundation system for today's development sites with poor ground conditions.

(d) The adoption of a "suspended" pre-cast "plank and pot" or similar flooring system, again ideally suited to high volume building methods.

The invention is described by reference to the following drawings - PS1, "Mini" pile/permanent shuttered in situ beam foundation system showing a general perspective of the "mini" piles, cast in situ beams Bnd walls above.

PS2 Details of "T" junction at pile location (type "C").

PS3 Details of special cutter to form pile aperture holes.

PS4 Details of shuttering trough at right angle junction (type "A").

PS5 Details of shuttering trough at straight section (type "B").

PS6 Details of shuttering trough at "T" junction (type "C").

PS7 Details of shuttering trough at cross-section (type "D").

Referring to the drawings, the overall foundation system comprises "mini" piles installed on a grid with spacings varying with the loading requirements.

The permanent shuttering is then installed along the gridlines over the piles, the pile apertures being cut with a special cutter.

The reinforcement previously fabricated off site is then laid in the shuttering troughs with additional bars fixed as required at junctions and in areas of high loading.

Account is taken in the design of the steel reinforcement of the tensile strength of the permanent shuttering system.

Ready-mixed concrete delivered to site by concrete bowser, which thus ensures good quality control, is then pumped into the shuttering troughs and vibrated in place to ensure thorough compaction.

Construction following setting of the concrete then proceeds, with above-ground requirements being walls, suspended pre-cast flooring systems and the like.

The system is most appropriate for high volume production where a number of units can be provided with pile foundations and thus all the beams may be constructed at the same time.

Claims (3)

CLAIMS.

1. A permanent shuttered in situ beam foundation system utilizing glass reinforced plastic or plastic extrusions in standard sections, allowing a minimum of concrete cover to the reinforcing steel and a minimum of steel reinforcement, taking into account the tensile strength of the trough shuttering material.

2. Standard shuttering-trough sections in glass reinforced plastic or plastic extrusions as claim 1.

produced in a factory and provided with "push fit" connections between adjoining components.

3. A special cutter fabricated from the steel casings utilized for the "mini" piles to cut pile apertures in the standard shuttering trough section as claimed in claim 1. or claim 2., thus allowing tolerances for the pile driving on site.