|Title of Invention||
AN ELONGATED PRE-CAST CONCRETE ELEMENT
|Abstract||AN ELONGATED PRE-CAST CONCRETE ELEMENT|
|Full Text||FORM 2
THE PATENTS ACT, 1970 [39 OF 1970]
COMPLETE SPECIFICATION [SEE SECTION 10 & RULE 13]
AN ELONGATED PRE-CAST CONCRETE ELEMENT
3 AHMADIAH CONTRACTING & TRADING, P O BOX 446, SAFAT 1305, KUWAIT,
The following specification particularly describes the nature of the invention and the manner in which it is to be performed:-
REINFORCED CONCRETE ELEMENT
Technical Field of the Invention The present invention relates to a reinforced concrete element
Background of the Invention
Reinforced concrete elements are generally used as building construction material for walls and slabs.
The predominant techniques used in reinfoiced concrete construction are mostfy based on previously set models. The technical research on reinforced concrete as a building construction materil
performance. Most of the applications in the field utilise heavy eqaipment, extensive amounts of formwork or a combination of both. Advanced technical know how is required but may not be readily available. All of these factor result in prohibitive or redundant costs.
Unfortunately, reinforced concrete is expensive. These costs are due to factors such as: cost of technical expertise cost of design supervison and stilled labour; cost of materials and material handling; equipment and labour formwork and related labour construction time.
It would therefore be desirable to have a reinforced concrete element which is designed such mat it maximises me benefits of the material and concurrently reduces costs.
Object of the Invention
It is an object of me present invention to overcome or ameliorate some of the disadvantages of the prior art or at feast to provide a useful alternative.
Summary of the Invention
There is firstly disclosed herein an elongated pre-cast concrete element, said element having:
longitudinally extending upper and lower generally parallel surfaces that enable me clement to be stacked with like elements when horizontally oriented; and
losgimdinally extending convex side surfaces joining the upper and lower surfaces.
There is further disclosed herein a wall structure including a plurality of elements, each dement being an element as hereinbefore defined, wherein the elements are stacked so each element is generally horizontally oriented,
The present invention, at least in a preferred embodiment preferably achieves the following: the elimination of fornwork fin: reinforced concrete slabs resolting in a drect cost saving and a positive environmental impact; the elimination of mandatory use of heavy equipment, intensive labour and advanced technical expertise; me substantial reduction in capital investment as a result of major savings achieved through the use of the elements alternative building material; and substantial reduction in the time required for fabrication and construction of walls and slabs.
Therefore, the present invention is preferably a pre-designed, pre-cast reinforced concrete element that is characterised by its cross sectional form, in an individual form, the elements can be utilised for other purposes such as walls of a building structure, partition walls, fencing, planters, tree support posts, pavement retaning walls, etc.
The present invention is yet farmer preferably easy to transport and handle without the use of heavyequipment
Preferably, the present invention is economical to fabricate and bufld and is gerieralh/inamtenancefree.
Brief Description of the Drawings
A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein:
figures lA and lB are cross-sectional views of two alternate embodiments of the element according to the present invention;
Figures 1C and 10 are cross-sectional view of moulds for the construction of the elements shown in Figuresl A and 1B isespeetrvery;
Figure IE is a side view of an element;
Figures IF and 1G are side views of a series of elements in accordance with Figures t A1 and IB fanning a slab;
Figure 1H is a side view of a series of elements in accordance wit FigurelA, forming a free standing wall;
Figure II is a side view of a series of elements in accordance with FigurelA, forming a wall where the elements are cemented together;
Figure 11 is a side view of a series of elements in accrdance with Figure 1 A, fonning a plastered wall;
Figure 2 is a perspective view of a series of elements in accordance with Figure 1A:
Figure 3 is a partial 3-dimensional view of a house showing use of a series of elements; and
Figure 4 is a partial 3-dhsenstonal cat away view of the roof of die house of Figore 3.
Detalled Description of the Preferred Embodiments
in Figures 1A, 11 to 1J and 2 there is depicted a preferred elongate pre-cast concrete element 5. The element 5 has longitudinally extending upper and lower generally parallel surfaces 10,15 mat enable the elements 5 to be stacked as shown, for example, in Figures 1I to 1J vertically to form a wall The element S farther includes longitttdinally exteading convex
1S to define a cross-section 17. A longitudinal passage 25 is located centrally and extends between end surfaces 12,13 and is adapted for receipt for a reinforcing element such as reinforced steel bar 30,
The convex sides 20 are designed to provide excellent load bearing capabilities: The preferred cross section 17 of the element 5 has dimensions 64 mm high and 75mm wide resulting in a cross sectional area 17 of the element 5 of 4170 square millimetres. The length of the element 5 can be any length, but generally between 100mm and 5OO mm Advantageously, the width and height of the cross section 17 can be varied to suite the required increase or decrease in the bearing capacity of fee element 5. Accosdingly, construction using the element
element cross sectional dimensions and its bearing capacity, with the only constant being the cross sectional design 17. These can be determined by the following
Structural Parameters And Analysis Of The element Under DIFFERENT
The design of the element 5 considers the loads and stresses from the following
• Fidlscrvkx loading in its permanent location
The element is deigned utilising the requirements of the ACI-318 code of practice.
The reinforcement percentage in the section is calculated as per the following equation:
Deflection limitations as governed by the limits stipulated in ACI-318 Code of Practice, Chapter 9. Other criteria like general detailing, cover to reinforcement etc. are as per ACI-318, Chapter 7. Local code requirements can be implemented keeping the ACI requirements as the minnnum acceptable.
• "a is the upper and lower flat surfaces 10,15 dimeasion of the element 5.
• "As" is the area of steel section used m reinforcement 30 of the element 5.
• "d" is the direction from the bottom of steel reinforcement 30 to the element upper surface 10.
A number of structural design tables have been formulated to provide
alternatives of cross sectional dimensions, reinforcement, lengths and load bearing
capacity. The tables located herein on pages 12 to 16 enable the user to choose the
optimum dimensions of cross section 17 and the lenght of the element 5. From the
tables it can be seen mat the linear metre weight of a single dement, the load bearing
capacity, the square metre cost are prime factor dictating the choice of the required dimensions.
In a preferred embodiment, steel bars 30 can be used for the reinforcement of the element 5. The diameter of the steel bets 30 and passage 12mm depending on the desired length of the bar and the required beraring capacity.in
mechanised production pre-stressed steel reinforcement can be used. in which case the span and bearing capacity of the element can be increased without any addition in the raw material.
Toe elements are preferably able to be handled without the need for heavy equipment The following table is based on a specific gravity of 2350 kg/cubic meter and illustrates the weights per length of a preferred form of the elements.
Length Weight in kg
0.50 rotter long 04.90
1.00 meter long 09.80
130 meter long 13.70
2.00 meter long 18.60
2.50 meter long 2430
3.00 meter long 29.40
330 meter long 3430
4.00 meter Jang 39.20
450 meter long 44.10
5.00 meter long 49.00
These elements also preferably have crushing strengths varying between 25 K e.g. for walls to 40 K as in roof slabs. In this regard, th physical characteristics of tbe ingredients; sand, gravel, cement, water and the weather temperature are basic contributors to the mix. hi most cases, the crashing strength of the concrete will be the decisive fector in identifying the various proportions of the mix. The Table below sets out me concrete mix used for building the pilot project
Table 1: Concrete Mix Design For The Pilot Project
Type of concrete K40
Type of cement OPC.
Type of mix PRODUCTION
Materials Aggregate %-SSD VoL Litri Spec
kg Natural Moist % Water Absorp
% Correct Weight kg
Cement 143 3.15 450 450
Water 185 1 185 173
Admixture 1.11 1Z77 13
Fine Aggregate (Sand) 268 2.61 700 S 1 728
Coarse Aggregate %" 2.7 1.5
1%2 196 2.7 530 1.5 522
3A 204 2.7 550 1.5 542
TOTAL 100% 1018 2428 2428
Turning now to the mode of production of the element 5, manual and mechanised methods are presently contemplated The manual production is well suited for a limited production of the elements. For an individual, wishing to construct his/her own home unit, the means and the process of production are dependent upon moulds 40, shown in Figures 1C and ID and are made out of material that allows multiple use and..
Elements 5 could be produced as fellows: procurement or fabrication of moulds
40; arranging moulds in batteries; placing reinforcement steel 30; mixing of concrete;
placing concrete in the mould 40 and vibrating as per standards; casting the reinforced
concrete; curing and storing. As preferably, the invention is intended to minimise the cost
of reinforced concrete elements, it is important that the mould material is obtainable and
that moulds fabricated from such material can be readily used without deterioration. The
most suitable materials found for the purpose are GRC or GRP or PVC or Polyethylene moulds cast to the form. The PVC or Polyethylene moulds are made in one piece and
because the mould material is flexible, ft allows casting of formwork without disturbing 1he moulds and/or the elements and easy removal of the mould after use.
Generally, moulds 40 ate arranged on specially prepared level casting flows,
reinmforcemen is set in position concrete is mixed and then cast into the mouids Small
size vibrators may be used to vibrate the concrete- The concrete should be retained in the moulds for a period of about threee days, during which time the concrete will be cured. The elements could men be removed from the moulds and stacked for future use. The moulds can then be rearranged for another cast.
If reinforcement is required the steel bars are laid in the mould and suspended in
the required postion by means of thin tie wires (not shown )or other suitable means . The
wires keep the reinforcement bars properly positioned while the concrete mix is poured.
The reinforcement bar should protrude beyond the ends of the moulds The reinforcing
could also be added later by casting a recess as in the preferred embodiment
Another presently contemplated mode of production is the mechanised mode
where the elements are produced on mass in a factory. Any practical length and width is
possible only being limited by the length awl width of the machines and the casting bed
The factory set up can be similar to the producation line of hollow core slabs . The same
prmcipies of mixing handling and casting of concrete appiy . That is, it can be a concrete
extrusion operation. The reinforcement bars for the elements can be eimer normal tension bars or pre-stressed bars. In the preferred emboditment of this invention normal reinforcement bar are used. In the case of mass production for wide scale commercial purposes, the elements can be produced in slabs of various widths and lengths. The slabs can range from 1 metre in length up to 5 metres and the width is anywhere between 0.6 metre wide up to 2 metres wide. AH dimensions will generally be limited only by the deflection allowable in relation to the length of the slabs. The elements can be stacked in a storage yard and sold on order. Tins allows spontaneous delivery of required material thus contributing to substantial reduction of construction time.
There are two main uses presently contemplate for the element 5:constructing walls 50 and structural slabs 55.in the first case, and as shown Figures 1H to 1J, the elements 5 can be assembled win or without mortar/cement 45, depending on me final treatment of the walls 50. For the slabs 55, .as shown in Figure1G.the elements 5 can be buitt on structural fames 57 and either cast in place, pre-cast or a steel frame. After arranging the elements 5 in place, a concrete topping 59 (see Figures 3 and 4) could be
poured to the thickness required. Further, as shown in Figures IB and 1G the upper surface may be rounded 60.
As shown in Figures 1H to l J, when constructing wall 50 the elements 5 stacked
vertically, with or without mortar 45. The element 5 can be restrained on both hoiizontal
end by concrete columns 65 as shown in Figures 3 and 4. The elements 5 are then laid
there between, either dry or with mortan 45 one top of the other . In tins arrangement,
the upper surface 10 on top of the element 5 with lact as a base for the following element 5. Dry construction of the dements 5 in walls 50 will usually include plaster 62 on the outside in order to weather tighten the walls 50. Further, casting the concrete framing columns 65 on site after building the elements 5 will allow an integral structural bonding between the dements 5 and te frame. This adds substantial structural rigidity to die building frame. If, however, the columns 65 are built in situ ahead of the elements 5, tiien the dements 5 will have to be bonded to the 65 by means of morter 45.Enough
space for this procedure can be provided by placing a pre-moulded groove 69 in the column to allow for the bonding mortar.
In embodiments includmg housing constraction, windows 70 may be opened in the wall 50 simply by casting the dements 5 to the specific dimensions required to allow the window opening to be formed. The dements can be cut to size on site or better pre¬fabricated to the required lengths. No special framing system is required for the windows and no lintels will be needed. The dements once plastered will produce the required window frame thickness. Depending on the insulation standards required for die building, the necessary insolation material is constructed. Altemativdy if the insulation of the exterior is not required, the inner face may be left without any treatment and/or may be plastered to produce a good internal finish face with plaster and paint as per die -standard practice. Depending upon the design requinrements, the exterior walls can be clad with marble, stone, granite, bricks or can be plastered and painted.
It is also foreshadowed thah elements can be used as internal partitions too. Farther, about 15 millimetres of plaster on each side of the partition will produce a 100 mm thick partition wall.
If considering structural slabs 55, as shown in Figures IE to lG based on the slab plans and the finishing beneath the slabs the length and the reinforcement of the elements
5 are decided; all fabrication of the dements should be to the pre-designed, required length. Moreover, cutting the elements to the required length on site is easy and can be achieved by means of an electric disc saw. The elements 5 are laid horizontally to the full
lengm and width of the slab area. If the clear span between the two end supports of the element is more man 2.5 metres, an intermediary support should be temporarily provided until the plain concrete slab topping 59 o f the elements 5 is poured and cored.
Further to the above, the elements 5 can be used in fencing posts and runners; warehouse wall closure; warehouse roof trusses; shoring panels closing between vertical structural supports; pavements substructures; and fruit trees groves and vineyards, however, they are not limited to only these uses.
As cost is important in the construction industry the following table and figures draw a comparative analysis between the elements of the present invention at least in a preferred embodiment and other concrete products, emphasising the economic implications.
Table A: Wais and Slab Analysis
Descriptioa Liaear Metre Square Metre Steel Reinforcement uss
Concrete and steel content in one element 0.00417 mc/kn Walls 0.063 cm/sqm Slabs 0.055 cm/sqm @6mm 0.226 kg/hn 3.01kg/sm. 54.87 kg/cm 6.78/sq m of Walls 107.20/cm of Walls
1 cubic metre concrete. 240 kn. Walls @ 15.80 sqm/cm Slabs© 18.00 sqm/cm @8mm 0.40 kg/hn 5.35kg/sqm. 97.556 kg/cm 10.00/sqm Slabs 180.00/cm in Slabs including 80mm/sq m thickness concrete topping of plant concrete topping -
1 cubic metre in concrete blocks 10*20*40. Not applicable 12.50 units 13.40/cm Not applicable 11.O0/ sq m.
1 cubic metre in reinforced concrete slab, average thickness 12cm. Not applicable 8 .33 sq m/cm 196\8.00/cm 23.60/sq m
Upon analysis of the above table it can be seta that, walls constructed using the elememts cf the present invention cost 61,60% of the standard 100mm thick sand cement blocks and slabs cost 42.37% of the standard I20mm thick reinforced concrete slabs.
The cost analysis of one cubic meter displayed in the table (cost is calculated on basis of Kuwait market prices) was calculated as follows:
Concrete material $ 42.00
Reinforced steel 55 [email protected]$249/MetricTon $ 13.69
Allow for casting, curing and transport to site $ 15.00
Allow for site handling and construction in walls $ 15.00
Sub-total cost/cubic Metre: $ 85. 69
Add 25% for overhead and profit S 21.42
Total cost/cubic metre $107.20.
Further differences wits the present invention is that normal block work construction is a "wet" trade whilst the present invention is a "dry" trade. This minimises the messiness on sites and will save on water consumption. Most block work requires plastering. The elements of the present invention can stay without plaster on the interior, for example, when providing for low cost housing, and still maintain an aesthetically acceptable took. Further, block work requires seven days coring time before it is allowed to be plastered whilst the elements can be plastered instantly. Still further, the transportation and mechanical handling costs are also reduced when simply considering that light and less material will be transported.
Further, when constructing slabs the labour rate for carpenters forming slabs is estimated at a minimum of US$42.80 per cubic metre and this is eliminated with the elements of the present invention. The need for wood and other sundries for formwork at US$18 per cubic metre is also preferabyl eliminated. A mimum of 30% of the concrete used in similar span solid slabs will be reduced by one third, yieldmg a saving in concrete quantity and in reinforcement of US$35.00/cubic metre. Total direct saving of labour, formwork and the reduction in quantities in slab concrete and reinforcement steel is US$95.80. This will produce a yield saving of apiroximatefy 64% of the prevailing cost of cubic metre of concrete of me classical slab system.
Is considezstics of the substantial direct savings mentioned above, there is an indirect saving effect that results from the reduction in the concrete and reinforcement quantities and the dead load. A proportional reduction to the foundation and the framing structure will result form the climination of deal weight on wall and on salbs .This will
yield a mimimm saving of 25% of die concrete and reinforcement value for the foundations and the framing of the structure. It is contemplated that there would be US$15.00 per cubicmetre in the foundation and me framing system.
As reinforced concrete is globally considered one of the most utilised material in the construction industry and is also expensive to acquire in its final form, people hi die low-income bracket would be substantially advantaged to use such a product
The element of the present invention is directed towards a segment of die world"s population by giving them a cost-effective and economically viable solution in order to address die cost issues and the difficulties involved in advanced technology. It does not eliminate all the problems but makes the solution much more attainable by die end user, it provides a standard solution to the construction of walls and slabs in any standard structure and in particular modular structures. The fact that the formwork for slabs, and in many parts of the world for wall construction, is relatively eliminated, a major saving on the use of wood for concrete construction purposes is achieved. This, on its own merit, will reflect positively on the issue of world forestry depletion.
Although die invention has been described with reference to specific examples would be appreciated by those skilled in the ait that the invention may be embodied in many other forms.
Table 2: Maximum Eteineitt Span Before Cracking
(tiam xl tar MlK Mo Ms span le lefty del
0.6 0.00! 38-2 5643 3864 2760 576 39.5 0.34 ii
0.8 0.00 84.7 5377 5964 3841 562 65.7 0.57 ti
1.0 0.00 96.1 5111 7583 3651 548 96.5 0.63 0.7
1.2 0.00J 131.4 4853 7960 3466 534 131.0 1.13 0.5
Table 3: Variation of Rainfoncemwrt Steal Diameter, Concrete Topping, Element Length, ABowabla and Actual Oeflectiofi and Load Bearing Limit
dSainj topp span Mac Mu Us ttfcap. A/cap. deft iBTRttZ UMITCPCTY
0.6J 5 500 27829 9208 65771 250.3 26.0 1.9 2.50 25.99
0.8 & 500 27220 15464 11046 470.6 216.4 3.1 2.50 122.S6
1.0 5 500 26619 22427 16019 682.6 428.3 4.5 2.50 122.S6
1.2 5 500 26024 29335 18589 792.1 537.8 S.2 2.50 122.96
0.6 6 500 34281 10277 7341 312.6 34.5 1.6 2.50 34.52
0.8 6 500 33605 17364 12403 528.5 2502 2.7 2.50 207.19
1.0 6 500 32937 25398 18140 772.9 494:7 4.0 2.50 207.18
1.2 6 500 32275 33611 23053 9813 704.0 5.1 2-50 207.18
0.6 7 500 41405 11346 8104 345.3 43.0 1.4 2.50 43.05
0.8 7 500 40862 1S264 13760 586.3 284.0 2.4 2.50 284.05
1.0 7 500 39926 28364 20260 8633 561.0 3.5 2.50 310.37
1.2 7 500 30187 37886 27081 1153.1 850.8 4.7 2.50 310.37
0.6 8 500 48202 12414 8867 377.8 51.6 12 2.50 51.58
0.8 8 500 48392 21164 15117 644.1 317.9 2.1 2.50 317.87
1.0 8 500 47588 31333 22381 953.6 627.4 3.1 2.50 434.01
1.2 8 500 46792 42161 30115 1283.2 956.9 4.2 £50 434.01
0.6 9 500 57670 13483 9631 410.4 60.1 1.1 2.50 60.10
0.8 9 500 56793 23064 16474 702.0 351.7 1.9 2.50 351.70
1.0 9 500 55923 34302 24501 1044.0 693.7 2.8 2.50 579.66
1.2 9 500 55059 46436 33166 1413.3 1063.0 3.8 2.50 579.66
06 10 500 66811 14552 10394 442.9 68.6 14 2.50 68.63
0.8 10 500 65866 24S64 17631 759.8 385.5 1.7 2.50 385.53
1.0 10 500 64929 37271 26622 1134.4 760.1 2.5 2.50 748.63
1.2 10 500 63998 50711 36222 1543.4 1169.2 3.4 2M 748.83
Table 3: contti
cKsnl tOOP span MTIC MU Ms tti cap. Ueap. deft lmt LIMIT CPCTY
0.6 5 450 27629 9206 6577 346.0 91.7 1.5 225 91.73
0.8 5 450 27220 15464 11046 581.0 326.B ,2.5 2 2£ 263.19
1.0 5 450 26810 22427 16019 842.7 588.4 3.7 in " 263.19
1.2 5 450 26024 28335 18589 977.8 723.6 4.3 2L25 • 283.19
0.6 6 450 34281 10277 7341 388.1 107.9 1.3 225 107.89
0.8 • 6 450 33605 17364 12403 652.4 374.2 22 225 374.18
1,0 6 450 32937 25396 18140 9542 676.0 32 225 3B7.66
1.2 6 450 32275 33611 23053 1212.7 934/4 4.1 225 387.68
0.6 7 450 -41405 11346 8104 4263 124.0 1.1 225 124.05
as 7 450 40662 19264 13760 723.8 421.6 1.9 225 421.57
1.0 7 450 39926 28364 20260 1065.8 76*5 Z9 225 538.11
1.2 7 450 39197 37886 27061 1423.5 1121.3 3.8 225 538.11
0.6 8 450 49202 12414 8867 466.5 1402 1.0 2.25 . 14020
0.8 8" 456 483S2 21164 i 15"li7 795.2 469.0 1.7 lis • 468.97
1.0 8 450 "47588 31333 22381 1177.3 851.1 2.5 225 716.64
1.2 8 450 46792 42161 30115 1584.2 1257.9 3.4 225 716.64
«*» «W span Mac Uu Ms fffcap. Id cap. deft lefbnt LMUrCPCJY
0.6 5 400 27829 9208 6577 437.9 183.6 1.2 2.00 183,63
0.8 5 400 27220 15464 11046 735.4 481.1 2.0 2.00 481.13
1.0 5 400 26619 22427 16019 1066.5 812.3 2.9 2.00 482.50
1.2 5 400 26024 29335 18589 1237.6 983.3 3.4 2.00 482.50
0.6 6 400 34281 10277 7341 488.7 210.5 1.0 2.00 210.46
0.8 6 400 33605 17364 12403 825-7 547.5 1.7 2.00 547.48
1.0 6 400 32937 25396 18140 1207.7 929.4 2.5 2.00 669.89
12 6 400 32275 33611 23053 1534.8 1256.6 32 2.00 669.B9
7 400 41405 11346 8104 539.5 237.3 0.9 ZOO 237.28
0.8 7 400 40662 19264 13760 9161 613.5 1.5 2.00 613.84
_« 7 400 39926 28364 20260 1348.9 1046.6 Z3 2.00 89428
12 - - 7 400 39197 37886 27081 1801.7 1499.4 3.0 2.00 89428
0.6 8 400 49202 12414 . 8867 590.4 264.1 0.8 2.00 264.11
0.8 8 400 48392 21164 15117" 1006.5 6802 1.4 2.00 68020
1.0 8 400 47588 31333 22381 1490.1 1163.3 2.0 2.00 1158.65
12 B 400 46792 42161 30115 2005.0 1678.7 2.7 2.00 1158.85
1. An elongated pre-cast concrete element, said element having:
longitudinally extending upper and lower generally parallel surfaces that enable the element to be stacked with like elements when horizontally oriented;
longitudinally extending convex side surfaces joining the upper and lower surfaces;
and a longitudinal passage extending between said end surfaces; and
a reinforcing element located in said passage so as to extend between said
2. A wall structure including a plurality of elements, each element being an element according to claim 1, wherein the elements are stacked so each element js generally horizontally oriented.
3. The wall structure according to claim 2, whereby between adjacent upper and lower surfaces of adjoining elements is a layer of mortar or cement.
Dated this 26th day of December 2001
BY HIS ADVOCATES, PATENT AND TRADE MARK CONSULTANTS
|Indian Patent Application Number||IN/PCT/2001/01646/MUM|
|PG Journal Number||20/2007|
|Date of Filing||26-Dec-2001|
|Name of Patentee||KASSIS FAHIM|
|Applicant Address||3 AHMADIAH CONTRACTING & TRADING PO BOX 446, SAFAT, 13005, KUWAIT, AUSTRALIA.|
|PCT International Classification Number||N/A|
|PCT International Application Number||N/A|
|PCT International Filing date||1999-12-03|