Title of Invention	AN IMPROVED BEAM FOR CONSTRUCTING A SLIM FLOOR AND A METHOD OF CONSTRUCTING THE SLIM FLOOR USING THE BEAM
Abstract	An improved beam for constructing a slim floor, by using the beam as substitute for the conventional reinforced cement concrete (RCC) beam, characterised in that the beam comprises a rolled steel beam (1) of I-section, a bottom steel plate (2) welded to the lower surface of bottom flange (3) of the I-section beam, a plurality of steel studs (6) fixed centrally by welding at required intervals in the longitudinal direction on the upper surface of top flange (7) of the I-section beam, a profiled deck (4) of steel sheet of required thickness having trough portions (4a) of trapezoidal sections mounted by tack welding at required intervals on the upper surface of the bottom steel plate (2) with the vertical section thereof lying in a plane parallel to the longitudinal side of the I-section beam and a RCC slab cast on the upper surface of both the I-section beam and profiled deck, encasing the I-section beam in the concrete. A method of constructing the slim floor using the improved beam is also disclosed. Reference: Figures 1 to 3 of the accompanying drawings.

Title of Invention

AN IMPROVED BEAM FOR CONSTRUCTING A SLIM FLOOR AND A METHOD OF CONSTRUCTING THE SLIM FLOOR USING THE BEAM

Abstract

An improved beam for constructing a slim floor, by using the beam as substitute for the conventional reinforced cement concrete (RCC) beam, characterised in that the beam comprises a rolled steel beam (1) of I-section, a bottom steel plate (2) welded to the lower surface of bottom flange (3) of the I-section beam, a plurality of steel studs (6) fixed centrally by welding at required intervals in the longitudinal direction on the upper surface of top flange (7) of the I-section beam, a profiled deck (4) of steel sheet of required thickness having trough portions (4a) of trapezoidal sections mounted by tack welding at required intervals on the upper surface of the bottom steel plate (2) with the vertical section thereof lying in a plane parallel to the longitudinal side of the I-section beam and a RCC slab cast on the upper surface of both the I-section beam and profiled deck, encasing the I-section beam in the concrete. A method of constructing the slim floor using the improved beam is also disclosed. Reference: Figures 1 to 3 of the accompanying drawings.

Full Text	The present invention relates to an improved beam for constructing a slim floor and a method of constructing the slim floor using the beam. The invention relates more particularly to a beam, called "slim floor beam", for use as a substitute for the conventional reinforced cement concrete (RCC) beam in the construction of buildings, bridges and warehouses, comprising a rolled steel beam of I-section having a bottom steel plate of width larger than that of the bottom flange of the I-section beam, which is welded to the lower surface of the bottom flange of the I-section been and a plurality of steel studs welded centrally along the length of the upper surface of the top flange thereof, a deck of steel sleet having a trapezoidal section mounted by tack welding on the upper surface of the bottom steel plate with the vertical section lying in a plane parallel to one longituditional side of the beam and a RCC slab cast on the upper surface of both the beam and deck encasing the beam in the concrete. The conventional reinforced cement concrete (RCC) beam is made of steel reinforcement bars and concrete mix in the following steps :- (i) fixing of props and shutters; (ii) cutting and bending of steel bars and stirrups for use as reinforcement; (iii) laying and lapping of the reinforcement bars fixed with stirrups thereon; (iv) preparing a concrete mix containing cement, sand, stone chip and water; - 2 - (v) casting of the concrete mix for making the RCC beam and floor slab in the shutters; (vi) curing of the cast; (vii) removing the props and shutterings; and (viii) finishing of the beam and floor slab. The main disadvantages of using RCC beams are :- (a) the depth of the RCC beams being increased with increase in load and span, these are virtually unacceptable for higher loads and larger span; and (b) their construction is time-consuming because of use of props and shutters, and the need for finishing of the beam. The aim of the present invention is to provide an alternative beam which is constructed at a faster rate without the need of propping (upto 6 m span), shuttering, and finishing, and can support heavier load at a wider span for the same depth of a conventional RCC beam. Thus the invention provides an improved beam for constructing a slim floor by using the beam as substitute for the conventional reinforced cement concrete (RCC) beam, characterised in that the beam comprises a rolled steel beam of I-section, a bottom steel plate welded to the lower surface of bottom flange of the I-section beam, a plurality of steel studs fixed centrally by welding at required intervals in the longitudinal direction on the upper surface of top flange of the I-section beam, a profiled deck of steel sheet of required thickness having trough portions of trapezoidal sections mounted by tack welding at required intervals on the upper surface of - 3 - the bottom steel plate with the vertical section thereof lying in a plane parallel to the longitudinal side of the I-section beam and a RCC slab cast on the upper surface of both the I-section beam and profiled deck, encasing the I-section beam in the concrete. The invention provides also a method of constructing the slim floor by using the beam comprising the following steps :-(i) cutting the required lengths of I-section of a rolled steel beam and bottom steel plate of width greater than the width of the bottom flange of I-section beam by means of gas cutting equipments; (ii) welding of bottom steel plate to the lower surface of bottom flange of I-section beam symmetrically and co-axially in the longitudinal direction of the beam; (iii) placing profiled deck having trough portions of trapezoidal sections, on steel plate at both sidesof I-section and fixing the deck to the steel plate in position by tack welding at the areas of contact thereof, the upper surface of the deck being provided with indentations or small mechanical anchors for attaining composite action between the deck and the RCC cast the reon, encasing the beam in concrete; (iv) fixing by welding a plurality of steel studs vertically along the central line on the upper surface of top flange of the I-section beam at required intervals in the longitudinal direction thereof, to act as shear connectors between the beam and the RCC slab; - 4 - (v) laying and lapping of reinforcement mesh on the upper surface of top flange of I-section beam in both the longitudinal and transverse direction of the slab and laying and lapping of reinforcement bars in each trough portion of the profiled deck; (vi) preparing the concrete mix of cement, sand, stone chip and water; (vii) casting of the concrete mix to form the slab; (viii) curing of the cast; and (ix) finishing of the slab. The invention is described fully and particularly in an unrestricted manner with reference to the accompanying drawings in v/hich - Figure 1 is a schematic view of the slim floor beam with its component parts; Figure 2 depicts a sectional view of the profiled dick; Figure 3 shows (a) transverse section and (b) longitudinal section of the slim floor beam mounted on columns. Referring the Figs. 1, 2 and 3, the steps followed for constructing the invented slim floor beam are :- 1) cutting the required lengths of a rolled steel I-section beam (1) and bottom steel plate (2) of width greater than the width of the bottom flange of I-section beam by means of gas cutting equipments; 2) welding of bottom steel plate (2) to the lower surface of bottom flange (3) of I-section beam symmetrically and co-axially in the longitudinal direction of the I-section beam; - 5 - 3) placing profiled steel plate deck (4) having trapezodial section (4a) on steel plate (2) and fixing the two in position by tack welding at their areas of contact, the upper surface of the deck being provided with indentations or small mechanical anchors for attaining composite action between the deck and the RCC slab (8) cast thereon encasing the I-section beam in concrete; 4) fixing by welding a plurality of steel studs (6) along the central line on the upper surface of top flange (7) of the beam at required intervals in the longitudinal direction thereof, to act as shear connectors between the beam and the RCC slab; 5) laying and lapping of reinforcement mesh (5) on the upper surface of top flange of I-section beam in both the longitudinal and transverse direction of the slab and lapping of reinforcement bars (5a) in each trough portion of profiled deck; 6) preparing the concrete mix of cement, sand, stone chip and water; 7) casting of the concrete mix to form the slab; 8) curing of the cast; and 9) finishing of the slab. In the typical embodiment of the slim floor beam, the rolled steel I-section beam is of specification No.ISMB 300 (depth 300 mm, flange width 140 mm, web thickness 7.5 mm, average flange thickness 12.4 mm) of grade SAIIMA 410 (Minimum - 6 - yield strength 410 MPa) and the steel plate welded to the bottom flange of the I-section beam is of 325 mm width,20 mm thickness, and, grade SAIIMA 410 (Minimum yield strength 410 MPa); the fixing studs acting as shear connectors are of 19 mm diameter, 70 mm length and yield strength more than 400 MPa; the concrete (of M-30 grade) slab over the top surface of the I-section beam is of thickness 85 mm, width 1250 mm and span (along the beam length) 5000 mm; the profiled deck is made of 1.25 mm thick cold rolled steel sheet (Minimum yield strength 250 MPa) with trapezoidal sections each of width 188 mm at the upper open side and 57 mm at the lower closed side, and placed at a distance of 600 mm centre to centre between the adjacent ones thereof as shown in Figure 2. The slim floor beam did not yield under a point load of upto 90T applied at mid-span during testing, 90T being the maximum capacity of the testing machine used. The deflection measured at the mid-span of the slim floor beam indicates that the beams are safe as per the code provision of IS s 800 : 1984 for service load limit. The slim floor beam is of advantage particularly in the construction of ware houses and large span buildings (as illustrated in Figs. 3(a) and 3(b)) as well as in the construction of bridge decks. Although the estimated cost of construction of a 7-storeyed building of length 25m and width 16m with column spacing 5m along length and 4m along width using the slim floor beam is of the same order as that of the building constructed - 7 - using the conventional RCC beams, there are certain other advantages of using the slim floor beam, such as, 1• The time of construction is expected to be less by about 20%. 2. The depth of the beam is less for the same load bearing capacity with effective higher floor height. 3. Seismic resistance is higher as ductility of the structure increases due to utilisation of a higher percentage of steel in slim floor beam. 4. Unhindered passages are available for the service lines• 5. The aesthetic appeal of the structure improves appreciably. - 8 - We Claim :- 1. An improved beam for constructing a slim floor, by using the beam as substitute for the conventional reinforced cement concrete (RCC) beam, characterised in that the beam comprises a rolled steel beam (1) of I-section, a bottom steel plate (2) welded to the lower surface of bottom flange (3) of the I-section beam, a plurality of steel studs (6) fixed centrally by welding at required intervals in the longitudinal direction on the upper surface of top flange (7) of the I-section beam, a profiled deck (4) of steel sheet of required thickness having trough portions (4a) of trapezoidal sections mounted by tack welding at required intervals on the upper surface of the bottom steel plate (2) with the vertical section thereof lying in a plane parallel to the longitudinal side of the I-section beam an! a RCC slab cast on the upper surface of both the I-section beam and profiled deckrencasing the I-section beam in the concrete. 2. The beam as claimed in claim 1, wherein the rolled steel I-section beam is of specification No. ISMB 300 (depth 300 mm, flange width 140 mm, web thickness 7.5 mm, average flange thickness 12.4 mm and of grade SAIIMA 410 (minimum yield strength 410 MPa). 3. The beam as claimed in claims 1 and 2, wherein the bottom steel plate is of width 325 mm and thickness 20 mm and of grade SAIIMA 410 (minimum yield strength 410 MPa) welded to the bottom flange of the I-section beam. - 9 - 4. The beam as claimed in claim 1, wherein the studs are each of diameter 19 mm, length 70 mm and yield strength more than 400 MPa, welded vertically along the centre line on the upper surface of top flange of the I-section beam at 220 mm interval. 5. The beam as claimed in claim 1, wherein the profiled deck is made of 1.25 mm thick cold rolled steel sheet (having minimum yield strength 250 MPa) containing indentations on the upper surface thereof. 6. The beam as claimed in claim 5, wherein the profiled deck comprises trapezoidal sections each of width 188 ram at the upper open side, width 56 mm at the lower closed side, depth 225 mm and placed at distance (centre to centre) of 600 mm between the adjacent ones. 7. The beam as claimed in claim 1, wherein the RCC slab is of thickness 85 mm, over top surface of the I-section beam, width 1250 mm and span (along the beam length) 5000 mm. 8. The beam as claimed in claim 7, wherein the RCC slab is made of M30 grade concrete. 9. A method of constructing the slim floor by using the beam as claimed in claims 1 to 8, comprising the following steps : (i) cutting the required lengths of I-section of rolled steel beam (1) and bottom steel plate (2) of width greater than the width of the bottom flange of I-section beam by means of gas cutting equipments; - 10 - (ii) welding of bottom steel plate (2) to the lower surface of bottom flange (3) of I-section beam symmetrically and co-axially in the longitudinal direction of the beam; (iii) placing profiled deck (4) having trough portions (4a) of trapezoidal sections, on steel plate (2) at both sides of I-section (1) and fixing the deck to the steel plate in position by tack welding at the areas of contact thereof, the upper surface of the deck being provided with indentations or small mechanical anchors for attaining composite action between the deck and the RCC cast thereon, encasing the beam in concrete (8); (iv) fixing by welding a plurality of steel studs (6) vertically along the central line on the upper surface of top flange (7) of the I-section beam at required intervals in the longitudinal direction thereof, to act as shear connectors between the beam and the RCC slab; (v) laying and lapping of reinforcement mesh (5) on the upper surface of top flange of I-section beam in both the longitudinal and transverse direction of the slab and laying and lapping of reinforcement bars (5a) in each trough portion of the profiled deck; (vi) preparing the concrete mix of cement, sand, stone chip and water; - 11 - (vii) casting of the concrete mix to form the slab; (viii) curing of the cast; and (ix) finishing of the slab. 10. An improved beam for constructing a slim floor, substantially as herein described and illustrated in the accompanying drawings. 11. A method of constructing the slim floor by using the beam, substantially as herein described. - 12 - An improved beam for constructing a slim floor, by using the beam as substitute for the conventional reinforced cement concrete (RCC) beam, characterised in that the beam comprises a rolled steel beam (1) of I-section, a bottom steel plate (2) welded to the lower surface of bottom flange (3) of the I-section beam, a plurality of steel studs (6) fixed centrally by welding at required intervals in the longitudinal direction on the upper surface of top flange (7) of the I-section beam, a profiled deck (4) of steel sheet of required thickness having trough portions (4a) of trapezoidal sections mounted by tack welding at required intervals on the upper surface of the bottom steel plate (2) with the vertical section thereof lying in a plane parallel to the longitudinal side of the I-section beam and a RCC slab cast on the upper surface of both the I-section beam and profiled deck, encasing the I-section beam in the concrete. A method of constructing the slim floor using the improved beam is also disclosed. Reference: Figures 1 to 3 of the accompanying drawings.

Full Text

The present invention relates to an improved beam for constructing a slim floor and a method of constructing the slim floor using the beam.
The invention relates more particularly to a beam, called "slim floor beam", for use as a substitute for the conventional reinforced cement concrete (RCC) beam in the construction of buildings, bridges and warehouses, comprising a rolled steel beam of I-section having a bottom steel plate of width larger than that of the bottom flange of the I-section beam, which is welded to the lower surface of the bottom flange of the I-section been and a plurality of steel studs welded centrally along the length of the upper surface of the top flange thereof, a deck of steel sleet having a trapezoidal section mounted by tack welding on the upper surface of the bottom steel plate with the vertical section lying in a plane parallel to one longituditional side of the beam and a RCC slab cast on the upper surface of both the beam and deck encasing the beam in the concrete.
The conventional reinforced cement concrete (RCC) beam is made of steel reinforcement bars and concrete mix in the following steps :-
(i) fixing of props and shutters; (ii) cutting and bending of steel bars and stirrups for
use as reinforcement; (iii) laying and lapping of the reinforcement bars fixed
with stirrups thereon; (iv) preparing a concrete mix containing cement, sand,
stone chip and water;
- 2 -

(v) casting of the concrete mix for making the RCC beam and floor slab in the shutters; (vi) curing of the cast; (vii) removing the props and shutterings; and (viii) finishing of the beam and floor slab.
The main disadvantages of using RCC beams are :-
(a) the depth of the RCC beams being increased with
increase in load and span, these are virtually
unacceptable for higher loads and larger span; and
(b) their construction is time-consuming because of use
of props and shutters, and the need for finishing
of the beam.
The aim of the present invention is to provide an alternative beam which is constructed at a faster rate without the need of propping (upto 6 m span), shuttering, and finishing, and can support heavier load at a wider span for the same depth of a conventional RCC beam.
Thus the invention provides an improved beam for constructing a slim floor by using the beam as substitute for the conventional reinforced cement concrete (RCC) beam, characterised in that the beam comprises a rolled steel beam of I-section, a bottom steel plate welded to the lower surface of bottom flange of the I-section beam, a plurality of steel studs fixed centrally by welding at required intervals in the longitudinal direction on the upper surface of top flange of the I-section beam, a profiled deck of steel sheet of required thickness having trough portions of trapezoidal sections mounted by tack welding at required intervals on the upper surface of
- 3 -

the bottom steel plate with the vertical section thereof lying in a plane parallel to the longitudinal side of the I-section beam and a RCC slab cast on the upper surface of both the I-section beam and profiled deck, encasing the I-section beam in the concrete.
The invention provides also a method of constructing the slim floor by using the beam comprising the following steps :-(i) cutting the required lengths of I-section of a rolled steel beam and bottom steel plate of width greater than the width of the bottom flange of I-section beam by means of gas cutting equipments; (ii) welding of bottom steel plate to the lower surface of bottom flange of I-section beam symmetrically and co-axially in the longitudinal direction of the beam; (iii) placing profiled deck having trough portions of
trapezoidal sections, on steel plate at both sidesof I-section and fixing the deck to the steel plate in position by tack welding at the areas of contact thereof, the upper surface of the deck being provided with indentations or small mechanical anchors for attaining composite action between the deck and the RCC cast the reon, encasing the beam in concrete; (iv) fixing by welding a plurality of steel studs
vertically along the central line on the upper surface of top flange of the I-section beam at required intervals in the longitudinal direction thereof, to act as shear connectors between the beam
and the RCC slab;
- 4 -

(v) laying and lapping of reinforcement mesh on the upper surface of top flange of I-section beam in both the longitudinal and transverse direction of the slab and laying and lapping of reinforcement bars in each trough portion of the profiled deck; (vi) preparing the concrete mix of cement, sand, stone chip and water; (vii) casting of the concrete mix to form the slab; (viii) curing of the cast; and (ix) finishing of the slab.
The invention is described fully and particularly in an unrestricted manner with reference to the accompanying drawings in v/hich -
Figure 1 is a schematic view of the slim floor beam with its component parts;
Figure 2 depicts a sectional view of the profiled dick; Figure 3 shows (a) transverse section and (b) longitudinal section of the slim floor beam mounted on columns.
Referring the Figs. 1, 2 and 3, the steps followed for constructing the invented slim floor beam are :-
1) cutting the required lengths of a rolled steel I-section beam (1) and bottom steel plate (2) of width greater than the width of the bottom flange of I-section beam by means of gas cutting equipments;
2) welding of bottom steel plate (2) to the lower surface of bottom flange (3) of I-section beam symmetrically and co-axially in the longitudinal direction of the I-section beam;
- 5 -

3) placing profiled steel plate deck (4) having trapezodial section (4a) on steel plate (2) and fixing the two in position by tack welding at their areas of contact, the upper surface of the deck being provided with indentations or small mechanical anchors for attaining composite action between the deck and the RCC slab (8) cast thereon encasing the I-section beam in concrete;
4) fixing by welding a plurality of steel studs (6) along the central line on the upper surface of top flange (7) of the beam at required intervals in the longitudinal direction thereof, to act as shear connectors between the beam and the RCC slab;
5) laying and lapping of reinforcement mesh (5) on the upper surface of top flange of I-section beam in both the longitudinal and transverse direction of the slab and lapping of reinforcement bars (5a) in each trough portion of profiled deck;
6) preparing the concrete mix of cement, sand, stone chip and water;
7) casting of the concrete mix to form the slab;
8) curing of the cast; and
9) finishing of the slab.
In the typical embodiment of the slim floor beam, the rolled steel I-section beam is of specification No.ISMB 300 (depth 300 mm, flange width 140 mm, web thickness 7.5 mm, average flange thickness 12.4 mm) of grade SAIIMA 410 (Minimum
- 6 -

yield strength 410 MPa) and the steel plate welded to the bottom flange of the I-section beam is of 325 mm width,20 mm thickness, and, grade SAIIMA 410 (Minimum yield strength 410 MPa); the fixing studs acting as shear connectors are of 19 mm diameter, 70 mm length and yield strength more than 400 MPa; the concrete (of M-30 grade) slab over the top surface of the I-section beam is of thickness 85 mm, width 1250 mm and span (along the beam length) 5000 mm; the profiled deck is made of 1.25 mm thick cold rolled steel sheet (Minimum yield strength 250 MPa) with trapezoidal sections each of width 188 mm at the upper open side and 57 mm at the lower closed side, and placed at a distance of 600 mm centre to centre between the adjacent ones thereof as shown in Figure 2. The slim floor beam did not yield under a point load of upto 90T applied at mid-span during testing, 90T being the maximum capacity of the testing machine used. The deflection measured at the mid-span of the slim floor beam indicates that the beams are safe as per the code provision of IS s 800 : 1984 for service load limit.
The slim floor beam is of advantage particularly in the construction of ware houses and large span buildings (as illustrated in Figs. 3(a) and 3(b)) as well as in the construction of bridge decks.
Although the estimated cost of construction of a 7-storeyed building of length 25m and width 16m with column spacing 5m along length and 4m along width using the slim floor beam is of the same order as that of the building constructed
- 7 -

using the conventional RCC beams, there are certain other advantages of using the slim floor beam, such as,
1• The time of construction is expected to be less by about 20%.
2. The depth of the beam is less for the same load bearing capacity with effective higher floor height.
3. Seismic resistance is higher as ductility of the structure increases due to utilisation of a higher percentage of steel in slim floor beam.
4. Unhindered passages are available for the service lines•
5. The aesthetic appeal of the structure improves appreciably.
- 8 -

We Claim :-
1. An improved beam for constructing a slim floor, by
using the beam as substitute for the conventional reinforced
cement concrete (RCC) beam, characterised in that the beam
comprises a rolled steel beam (1) of I-section, a bottom steel
plate (2) welded to the lower surface of bottom flange (3) of
the I-section beam, a plurality of steel studs (6) fixed centrally by welding at required intervals in the longitudinal direction on the upper surface of top flange (7) of the I-section beam, a profiled deck (4) of steel sheet of required thickness having trough portions (4a) of trapezoidal sections mounted by tack welding at required intervals on the upper surface of the bottom steel plate (2) with the vertical section thereof lying in a plane parallel to the longitudinal side of the I-section beam an! a RCC slab cast on the upper surface of both the I-section beam and profiled deckrencasing the I-section beam in the concrete.
2. The beam as claimed in claim 1, wherein the rolled
steel I-section beam is of specification No. ISMB 300 (depth
300 mm, flange width 140 mm, web thickness 7.5 mm, average flange thickness 12.4 mm and of grade SAIIMA 410 (minimum yield strength 410 MPa).
3. The beam as claimed in claims 1 and 2, wherein the
bottom steel plate is of width 325 mm and thickness 20 mm and
of grade SAIIMA 410 (minimum yield strength 410 MPa) welded to
the bottom flange of the I-section beam.
- 9 -

4. The beam as claimed in claim 1, wherein the studs
are each of diameter 19 mm, length 70 mm and yield strength
more than 400 MPa, welded vertically along the centre line on
the upper surface of top flange of the I-section beam at
220 mm interval.
5. The beam as claimed in claim 1, wherein the profiled
deck is made of 1.25 mm thick cold rolled steel sheet (having
minimum yield strength 250 MPa) containing indentations on the
upper surface thereof.
6. The beam as claimed in claim 5, wherein the profiled
deck comprises trapezoidal sections each of width 188 ram at the
upper open side, width 56 mm at the lower closed side, depth
225 mm and placed at distance (centre to centre) of 600 mm
between the adjacent ones.
7. The beam as claimed in claim 1, wherein the RCC slab
is of thickness 85 mm, over top surface of the I-section beam,
width 1250 mm and span (along the beam length) 5000 mm.
8. The beam as claimed in claim 7, wherein the RCC slab
is made of M30 grade concrete.
9. A method of constructing the slim floor by using the
beam as claimed in claims 1 to 8, comprising the following steps :
(i) cutting the required lengths of I-section of rolled steel beam (1) and bottom steel plate (2) of width greater than the width of the bottom flange of
I-section beam by means of gas cutting equipments; - 10 -

(ii) welding of bottom steel plate (2) to the lower surface of bottom flange (3) of I-section beam symmetrically and co-axially in the longitudinal direction of the beam; (iii) placing profiled deck (4) having trough portions (4a) of trapezoidal sections, on steel plate (2) at both sides of I-section (1) and fixing the deck to the steel plate in position by tack welding at the areas of contact thereof, the upper surface of the deck being provided with indentations or small mechanical anchors for attaining composite action between the deck and the RCC cast thereon, encasing the beam in concrete (8);
(iv) fixing by welding a plurality of steel studs (6) vertically along the central line on the upper surface of top flange (7) of the I-section beam at required intervals in the longitudinal direction thereof, to act as shear connectors between the beam and the RCC slab; (v) laying and lapping of reinforcement mesh (5) on the upper surface of top flange of I-section beam in both the longitudinal and transverse direction of the slab and laying and lapping of reinforcement bars (5a) in each trough portion of the profiled deck;
(vi) preparing the concrete mix of cement, sand, stone chip and water;
- 11 -

(vii) casting of the concrete mix to form the slab; (viii) curing of the cast; and (ix) finishing of the slab.
10. An improved beam for constructing a slim floor, substantially as herein described and illustrated in the accompanying drawings.
11. A method of constructing the slim floor by using the beam, substantially as herein described.
- 12 -
An improved beam for constructing a slim floor, by using the beam as substitute for the conventional reinforced cement concrete (RCC) beam, characterised in that the beam comprises a rolled steel beam (1) of I-section, a bottom steel plate (2) welded to the lower surface of bottom flange (3) of the I-section beam, a plurality of steel studs (6) fixed centrally by welding at required intervals in the longitudinal direction on the upper surface of top flange (7) of the I-section beam, a profiled deck (4) of steel sheet of required thickness having trough portions (4a) of trapezoidal sections mounted by tack welding at required intervals on the upper surface of the bottom steel plate (2) with the vertical section thereof lying in a plane parallel to the longitudinal side of the I-section beam and a RCC slab cast on the upper surface of both the I-section beam and profiled deck, encasing the I-section beam in the concrete.
A method of constructing the slim floor using the improved beam is also disclosed.
Reference: Figures 1 to 3 of the accompanying drawings.

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Patent Number

210001

Indian Patent Application Number

01544/CAL/1998

PG Journal Number

37/2007

Publication Date

14-Sep-2007

Grant Date

13-Sep-2007

Date of Filing

28-Aug-1998

Name of Patentee

STEEL AUTHORITY OF INDIA LIMITED

Applicant Address

ISPAT BHAWAN, LODHI ROAD, NEW DELHI-110003.

Inventors:

#	Inventor's Name	Inventor's Address
1	DEBASHIS KARMAKAR	RDCIS/SAIL, DORANDA, RANCHI-834002.
2	SAMIR KUMAR GHOSH	RDCIS/SAIL. DORAMDA, RANCHI-834002
3	PUNEET KUMAR MAINI	RDCIS/SAIL. DORAMDA, RANCHI-834002
4	SUBRAT KUMAR MOHAPATRA	RDCIS/SAIL. DORAMDA, RANCHI-834002
5	DEBASIS MUKHERJEE	RDCIS/SAIL, DORANDA, RANCHI-834002.

PCT International Classification Number

E 04 B 5/10

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA