CN106049670A - Embedded type steel truss system - Google Patents

Abstract

The invention discloses an embedded steel truss system, comprising an embedded truss and an embedded steel beam. The embedded truss includes an upper chord and a lower chord arranged parallel to each other and is vertically fixed to the upper chord and the lower chord. The straight web bar between them, and the oblique web bar whose two ends are respectively fixed at the connection between the upper chord or the lower chord and the straight web bar; the embedded steel beam includes the I-beam and the Stiffeners; welding studs are welded on the lower flange of the top chord, and shear members are welded on the web. The force of the present invention is more reasonable, and the material is more economical. Embedding steel trusses and steel beams in the transfer plate can save the floor height occupied by the bending system on the one hand, and save materials by utilizing the compressive performance of the concrete slab.

Description

Embedded steel truss system

technical field

The invention relates to fixing buildings, especially a composite structure truss.

Background technique

In large public buildings, as the floor changes, the column network will change. At a certain floor of the floor, there will be more column members than the lower floor. This floor is called the transfer floor. In order to support the beams and columns of the upper floor, the floor slabs of the transfer floor generally have thick slabs, the thickness of which is generally more than 1000mm, and some can reach 3000mm. If a conventional beam-slab system is used in the transfer floor, the cross-sectional height of the beam will be quite large due to the large floor load, which will affect the net floor height of the transfer floor, and the use of too many materials will make the structure unreasonable.

Contents of the invention

The object of the present invention is to provide an embedded steel truss system to solve the above-mentioned problems in the prior art.

The core content of the present invention is an embedded steel truss system, including an embedded truss and an embedded steel beam, the embedded truss includes upper chords and lower chords arranged and the straight web bar between the lower chord, and the diagonal web bar whose two ends are respectively fixed at the connection between the upper chord or the lower chord and the straight web bar; the embedded steel beam includes an I-beam and a The stiffener on the plate; welding studs are welded on the lower flange of the upper chord, and shear members are welded on the web.

Preferably, the bottom chord is a rectangular steel pipe structure, and the negative moment area is filled with concrete. The interior of the straight web bar is filled with concrete. Steel plates are welded at the ends of the straight web bar and the diagonal web bar. The bottom of the upper chord is welded with a steel base, and the steel base is provided with a vertically downward and inclined steel sleeve, and the straight web and diagonal web are fixed on the steel sleeve.

Preferably, the upper flange of the upper chord is buried in the concrete of the floor slab, and the concrete in the floor slab, the lower chord and the straight web includes the following components in parts by weight: cement 380-420, medium sand 500 -700, glass fiber 15-25, water 180-200, coarse aggregate 800-1000, fly ash 20-40, water reducing synergist 3-5.

Preferably, the structural formula of the water reducing synergist is:

In the formula, a:b:c=1:1.2:1, n is 45-50, m is 45-50, and d is 50-80.

The working principle and advantages of the present invention are: the steel truss and steel beam system are used to replace the traditional beam-slab system in the transfer layer, which will make the structural force more reasonable and save materials. Embedding the steel trusses and steel beams in the transfer plate can save the floor height occupied by the bending system on the one hand, and save materials by utilizing the compressive performance of the concrete slab.

Description of drawings

Figure 1 is a plan view of the present invention.

Figure 2 is a schematic structural view of the truss.

Fig. 3 is a sectional view of the upper chord.

Figure 4 is a cross-sectional view of a steel beam.

Figure 5 is a structural schematic diagram of a steel node.

detailed description

As shown in FIG. 1 , the embedded steel truss system is mainly composed of two parts: an embedded truss 1 and an embedded steel beam 2 . As shown in FIGS. 2 and 3 , the embedded truss is composed of an upper chord 11 , a lower chord 12 , a straight web 13 and a diagonal 14 .

The upper chord is completely embedded in the high-strength concrete 11h of the roof panel of the transfer floor, and the upper chord is composed of an upper flange 11e, a lower flange 11c, a steel web 11d, a welding stud 11a and a shear member 11f. The lower flange is welded to the steel bottom plate 11g by welding studs, and the steel bottom plate is used as the bottom plate when the transfer floor slab is poured. The welding studs make the lower flange and the transfer floor slab tightly occluded, and no bond slippage occurs. The shear member is connected with the upper flange and the steel web through fillet welds to prevent the upper flange and the steel web from bonding and slipping with the transition floor slab. There is a hole at the bottom of the steel web so that the prestressed steel bars 11b can pass through.

The lower chord is a rectangular steel pipe structure, and concrete is filled in the negative bending moment area to prevent buckling of the steel pipe under compression and improve the bearing capacity of the chord. The oblique web and the straight web are both round steel pipe structures, and the interior of the straight web is filled with concrete to improve the compressive capacity. The ends of the straight and diagonal webs are covered with threads, and the two ends are welded with steel plates to prevent the concrete from deteriorating due to moisture loss during welding.

The embedded steel beam 2 has an I-shaped cross-section, the upper flange and the web are all buried in the concrete 24 of the transfer floor slab, and the lower flange is exposed and located below the bottom plate 21 . Stiffeners 23 are welded on the web of the steel beam to improve the anti-slip performance of the steel beam and the concrete slab. The web is welded with the steel bar sleeve 22 at the position where the steel bar 25 passes through, so as to avoid bending the steel bar and ensure the continuity of the stress of the steel bar at the same time.

The diagonal and straight webs are welded to the upper and lower chords through steel nodes. The steel node consists of a steel base 3 and a steel sleeve 4 . The steel base is a solid disc welded to the flanges of the upper and lower chords. The steel sleeve is welded on the steel base, the inner sleeve has threads, and the edge of the mouth has no threads within 20mm. After tightening the straight web rod and the diagonal web rod, they are connected by fillet welds in the non-threaded area.

The implementation process of the present invention is as follows: the embedded steel truss is assembled in the factory. Lift the buried steel truss to the designated position, and rigidly connect the truss to the supporting structure. The embedded steel beams and embedded steel trusses are connected by hinged joints. A steel floor is laid between the lower flange of the embedded steel beam and the upper chord of the embedded steel truss. The steel bottom plate is connected with the lower flange of the embedded steel beam through fillet welds, and connected with the upper flange of the embedded steel truss through welding studs. The concrete transfer floor slab is poured with the steel bottom slab as a formwork and maintained properly.

In use, the floor slabs transfer loads to the embedded steel beams, causing the embedded steel beams to flex. The lower flange of the steel beam is in tension, and the upper flange and the concrete in its vicinity are in tension together. The steel beam ends transmit the shear forces to the embedded trusses. In the positive bending moment zone, the upper chord of the truss and the internal concrete are under common compression, and the surrounding concrete is used as a constraint to prevent the steel structure from buckling, and the steel pipes in the lower chord are under tension; in the negative bending moment zone, the upper and lower flanges and webs of the truss upper chord are under compression, The compression capacity of the upper chord can be fully exerted, the steel pipe of the lower chord is under pressure together with the internal concrete, and the concrete inside the steel pipe acts as a steel pipe constraint to prevent its buckling.

In further implementation, the composition of concrete is optimized. In parts by weight, the concrete includes the following components: cement 380-420, medium sand 500-700, glass fiber 15-25, water 180-200, coarse aggregate 800-1000, fly ash 20-40, water reducing Synergists 3-5.

Wherein, the structural formula of the water-reducing synergist is:

In the formula, a:b:c=1:1.2:1, n is 45-50, m is 45-50, and d is 50-80.

Experiment 1-8

example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 cement 400 380 420 390 410 425 375 395 Middle sand 580 620 560 660 500 700 540 710 glass fiber 20 18 twenty two 25 15 13 28 twenty four water 195 190 200 180 185 205 175 180 Coarse aggregate 920 880 960 840 1000 800 780 1020 fly ash 30 twenty two twenty four 26 32 38 40 20 water reducing synergist 4.2 4.6 3.6 3.2 2.8 4.4 4.8 5.0 3d intensity 150 160 140 145 150 170 160 140 28d strength 165 165 155 160 175 180 160 165 Freeze and thaw 200 times qualified qualified qualified qualified qualified qualified qualified qualified Durability pass pass pass pass pass pass pass pass

Note: The control group is concrete using ordinary water reducing agent, its 3d strength is 130Mpa, and its 28d strength is 135Mpa.

In short, using steel truss and steel beam system instead of traditional beam-slab system in the transfer floor will make the structure more reasonable and save materials. Moreover, embedding the steel trusses and steel beams in the transfer slab can save the net floor height occupied by the bending system on the one hand, and on the other hand use the compressive performance of the concrete slab to save materials.

Claims (7)

1. a flush type steel girder system, it is characterised in that include embedded type truss and embedded type girder steel, described embedded type purlin The vertical web rod that frame includes top boom arranged in parallel and lower boom, is perpendicularly fixed between top boom and lower boom, and Two ends are individually fixed in the diagonal web member of top boom or lower boom and vertical web rod junction；Described embedded type girder steel include I-beam and The ribbed stiffener being welded on I-beam web；On the lower flange of top boom, welding weldering nail, web is welded with shear key.

2. flush type steel girder system as claimed in claim 1, it is characterised in that tying for rectangular steel pipe of described lower boom Structure, hogging moment area is filled with concrete.

3. flush type steel girder system as claimed in claim 1, it is characterised in that the inside of described vertical web rod is filled with coagulation Soil.

4. flush type steel girder system as claimed in claim 1, it is characterised in that the end weldering of described vertical web rod and diagonal web member It is connected to steel plate.

5. the flush type steel girder system as described in any one of Claims 1-4, it is characterised in that the bottom of described top boom Be welded with steel base, steel base be provided with vertically downward with tilt steel bushing, described vertical web rod and diagonal web member are consolidated in steel bushing On cylinder.

6. flush type steel girder system as claimed in claim 5, it is characterised in that the top flange of described top boom is embedded in flooring In the concrete of plate, in terms of parts by weight, the concrete in floorboard and lower boom and vertical web rod includes following component: cement 380-420, medium sand 500-700, glass fibre 15-25, water 180-200, coarse aggregate 800-1000, flyash 20-40, diminishing increases Effect agent 3-5.

Flush type steel girder system the most according to claim 6, it is characterised in that the structural formula of described diminishing synergist For:

In formula, a:b:c=1:1.2:1, n are 45～50, and m is 45～50, and d is 50～80.