FLOOR STRUCTURE FOR BUILDINGS

Abstract: Floor structure for a building, for example, a parking garage, comprising primary beams (12), secondary beams (16-20) suspended on the primary beams and a lost form of sheet metal placed on the secondary beams. A concrete slab is poured in place in the form, which is trapezoidal and corrugated so that the concrete beams (47) are formed in the lower flanges of the form. The primary beams are lowered into the primary beams so that the concrete beams (47) are located below the level of the upper flanges (53) of the primary beams.

Description: Floor structur fcr buildings. This invention relates to a floor structure for build¬ ings comprising primary beams, secondary beams supported by the primary beams and a reinforced concrete slab, cast in place, supported by the secondary beams, in which the second ary beams are placed between the flanges of the primary beams. According to the invention, the floor structure compris a set of materials, where the best qualities of the various materials are combined so that the floor structure, besides 10 being technically acceptable and allowing large spans to be covered, are also economically advantageous and can shorten the time required for construction. Furthermore, a floor structure designed according to the invention is easy to dismantle and has high recovery value, qualities which are *•** - * ' becoming increasingly essential. The invention is described in greater detail below, with reference to the accompanying drawings which illustrate by way of example the floor structure as used in a parking garage. Figure 1 shows a side view of a portion of the ** *•• -' floor structure. Figure 2 is a cross section along Line 2-2 in Figure 1. Figure 3 is a cross section as in Figure 2 of an alternative embodiment of the invention. Figure 1 shows a portion of a parking garage and a portion of the floor structure used in its construction. ■ ~~~ ~ Primary beams 11, 12 and 13 are placed on uprights 14, 15. Secondary beams 16-20 in the form of rolled I-beams are placed between the primary beams and are oriented perpen¬ dicular to the latter. Drain conduits 22 are placed between the rows of up- 30 rights 14 and 15. The primary beams are welded I-beams as shown in Figure 2 with arched upper flanges 23 and straight lower flanges 24 as shown in Figure 1. Figure 2 shows two coaxial secondary beams, on one 35 hand, beam 17, which is shown in Figure 1 and, on the other hand, beam 25. They have end flanges designated 26 and 27, which rest on supports 28, 29 welded onto the web 30 of the primary beam 12. Secondary beams 17, 25 are held together by bolts 31. Shims 32, 33 are placed between the webs of the primary beams 12 and the flanges 26, 27 of the second¬ ary beams. Placed on top of the secondary beams are trapezoidal corrugated plates 35, 36 and 37 in lengths which are as long as the primary beams. An overlapping joint between the two plates 35, 36 is shown at 38 in Figure 2. Above the upper flange 23 of each primary beam, as shown in Figure 2, is a flat plate 41, which has overlapping joints 39, 40 against the trapezoidal corrugated plates 35, 37 on each side of the primary beam 12. The plates are attached by bolts, as indicated by 43, in several places, and the plate deck created is used as a lost form for a concrete slab 44 which is cast in place. On the lower edge of the concrete slab 44, the trapezoidal-profile plate forms beams which, since the upper flanges 42 of the secondary beams 16-20 are on a substantially lower level than the upper flanges 23 of the primary beams, will be located essentially beneath the upper flanges 23 of the primary beams. These concrete beams have all been designated 47. The concrete slab 44 is rein-, forced against cracking with a reinforcing mesh 46. The sheet metal form around the beams 47 of the concrete slab 44 is load bearing, but the beams may also be strengthened by longitudinal reinforcing rods 48. The reinforcement in the concrete slab 44 and its beams 47 is extremely simple. It can therefore be installed rapidly, which reduces the time required for construction. The upper flanges of the primary beams 12 are arched in the central portion located between the secondary beams, as shown in Figure 1. The arch is essentially the shape that the plates 35, 36, 37 would assume under their own weight if they were placed so that they were supported only on a center support. Outside the secondary beams 17 and 19, the upper flanges 23 are straight but inclined. The connec¬ tion between the arched portion and both straight portions is preferably asymptotic. The attachment of the secondary beams 16-20 joins the arched shape of the upper flanges of the primary beams. This arch facilitates the installation of the plate, and contributes a slope suitable for the deck of a parking garage. In addition, there can be a thickening of the concrete toward the middle if the surface of the concrete is placed straight against a ridge above the center of the primary beam which is advantageous for a parking garage, since that is where the driving lanes are preferably located. Between the ends of the primary beams 19, 13 and perpendicular to the primary beams, the drain conduits 22 run connected to drain pipes, along with the support pillar 15 for the primary beams. The drain conduits drain not only the surface of the concrete, but also the formwork plate if moisture develops between the formwork plate and the concre¬ te. The plate therefore constitutes an extra sealing layer. Figure 3 shows an alternative embodiment, in which the trapezoidal corrugated plate has an upper flange 50, which is wide enough to completely cover the upper flange 23 of the primary beam. The upper flange 50 has transverse rein¬ forcing embossments to increase its rigidity, and the seams 51, 52 are vertical in the middle of the lower flanges, and extend at least to the level of the upper flanges 50 or somewhat higher, as shown in the figure. Each plate there¬ fore comprises one-half narrow lower flanges 53, 54 on either side of a wide upper flange 50. The vertical seams form reinforcements for the concrete. A lower flange 52 and a lower flange 53 on a plate next to it therefore together form one complete bottom flange. A reinforcement against cracking in the form of a mesh can also be used, as shown in Figure 2. The sheet metal in the vertical seams can also be provided with small bosses or indentations to increase its adhesion to the concrete. This design of the plates shown in Fig 3 can shorten the time required for construc¬ tion even further.

Claims: CLAIMS 1. Floor structure for buildings, comprising primary beams (12) , secondary beams (16-20) supported by the primar beams, and a concrete slab (44) cast in place in a lost form that is made of metal and supported by the secondary beams, the secondary beams being placed between the upper and lower flanges of the primary beams (23, 24) , c h a r a c t e r i z e d in that the upper sides of the secondary beams (16-20) are on a significantly lower level than the upper sides of the primary beams (11, 12, 13) and that the metal forms , (35, 36, 37, 41) have a profile paral¬ lel to that of the primary beams so that the concrete beams (47) created are parallel to the primary beams and are located significantly below the level of the upper sides of the primary beams, while otherwise, the concrete slab (44) is located significantly above the primary beams. 2. Floor structure according to Claim 1, c h a r a c t e r i z e d in that a plate covering (41) above a primary beam forms sealed floor structure between plates located on either side of the primary beam (12) . 3. Floor structure according to Claim 1 or 2, c h a r a c t e r i z e d in that the plate form comprises plates (35, 36, 37) which extend along the entire length of the primary beams (11, 12, 13) and that the upper flanges (23) of the primary beams are arched, at least in a central section. 4. Floor structure according to Claim 3, c h a r a c t e r i z e d in that the above-mentioned central section is arched, so that it has essentially the same shape as the form plate would assume under its own weight, if it were balanced only on a central support. 5. Floor structure according to one or more of the above Claims, c h a r a c t e r i z e d in that the plate forms have an essentially trapezoidal cross section with wide upper flang es (50) and narrow lower flanges (53, 54) wherein the seams between the plates of the sheet metal form are provided in the lower flanges; these seams (51, 52) are upstanding at least to the level of the upper flanges and provide rein¬ forcements in the concrete. 6. Floor structure according to Claim 4, c h a r a c t e r i z e d in that the upper flanges 50 have transverse embossments. 7. Floor structure according to one or more of the above Claims, c h a r a c t e r i z e d in that the secondary beams (16-20) have welded end plates (26, 27) which rest on the welded supports (28, 29) of the primary beams (12), and that bolts which run all the way through are used to tighten together in paris the upper ends of two end plates (26, 27) facing one another on either side of the web of a primary beam. 8. Floor structure for buildings, comprising primary beams (12) , secondary beams (16 -20) supported by the primary beams, and a cast-in-place concrete slab (44) supported by the secondary beams, the secondary beams being placed between the upper and lower flanges of the primary beams (23, 24) c h a r a c t e r i z e d in that at least a central portion of the upper flanges (23) of the primary beams are slightly arched and a lost form of sheet metal (35, 36, 37, 41) is supported by the secondary beams and conforms to the arch of the upper flange of the primary beam (23), the upper surface of the concrete slab being substantially straight with an inclination in both directions from the centre of the primary beams so that the thickness of the concrete slab gradually increases towards the ridge of the concrete slab that is formed a long the centers of the primary beams.

Inventors: JOHANSSON GUNNAR, JOHANSSON, GUNNAR
Applicants: SSAB SVENSKT STAL AB, SSAB SVENSKT STAAL AB
Application year: 1988
Main classification: E04B5
IPC codes: E04B5