Novel beam string type cantilever I-shaped steel beam structure capable of adjusting bearing capacity and rigidity

Abstract

A beam string type cantilever I-shaped steel beam structure capable of adjusting bearing capacity and rigidity comprises an I-shaped steel main beam, a supporting rod, a support, a prestress steel cable, a steel base plate and a U-shaped bolt. The U-shaped bolts are pre-embedded in preset positions of a floor slab and matched with the steel base plates to limit and fix the I-shaped steel main beam at one end of the inner side of the floor slab, the supporting rods are arranged on the upper surface of the I-shaped steel main beam, and the other end of the I-shaped steel main beam extends out of the outer side of the floor slab to serve as an erecting platform of the cantilever scaffold. The supporting rod is connected with the pair of supports through a prestress steel cable. The cantilever load can be transmitted to the floor concrete structure of the floor, the bearing capacity and rigidity of the structure can be adjusted according to different load working conditions and structural rigidity requirements, mounting and dismounting are easy and convenient, high-altitude outdoor operation is not involved, and the method has the advantages of being high in construction efficiency, good in construction safety, high in load bearing capacity, good in economical efficiency and low in cost. And the cost is saved.

Description

Technical Field

[0001] The invention relates to the technical field of cantilever I-beam construction, in particular to a novel beam-string cantilever I-beam structure with adjustable bearing capacity and rigidity. Background Art

[0002] In the construction process of high-rise buildings, cantilever scaffolding is often used, and cantilever I-beams are generally used as the frame unloading objects of cantilever scaffolding. As the scaffolding is continuously built, the load acting on the cantilever I-beams continues to increase. When the load level is high, due to the material properties of the steel itself and the cantilever length, the bearing capacity of the cantilever I-beam itself and the displacement of the cantilever end caused by the load pose a challenge to the structural safety. At this time, it is often necessary to provide additional support and reinforcement to the cantilever I-beam to enhance the bearing capacity and stiffness of the cantilever I-beam to meet the higher bearing capacity and structural safety requirements.

[0003] The current cantilever I-beam support reinforcement methods can be roughly divided into two types: "upper pull" and "lower support". Among them, the "upper pull" method fastens the cantilever I-beam to the upper structure of the building; the "lower support" method uses the lower structure of the building to support the cantilever I-beam. The two current methods support the cantilever I-beam of the current layer based on the upper and lower adjacent layer structures, which are difficult to construct and have high construction costs.

[0004] The disadvantages of the current method are as follows:

[0005] 1. The process is complicated and the construction is difficult. It involves a large amount of material pre-embedding and subsequent manual removal and cleaning operations, which is labor-intensive, time-consuming and has high labor costs.

[0006] 2. Poor versatility. The reinforced cantilever I-beam can only meet the current needs of the current project and cannot be adjusted. It has poor versatility and needs to be processed again after being dismantled and transferred to another project.

[0007] 3. Poor safety. The reinforcement operation requires a lot of manual outdoor operations at high altitudes, which poses a high safety hazard. Summary of the invention

[0008] The purpose of the present invention is to provide a new type of cantilever I-beam structure with adjustable bearing capacity and stiffness. By setting up I-beam main beams, prestressed steel cables, supports, struts and other components, and being able to adjust bearing capacity and stiffness, the cantilever end load is transferred to the current floor slab without relying on the support of the adjacent layer structure. The shortcomings of the current cantilever I-beam support reinforcement method, such as complicated procedures, poor versatility and safety, are solved. It can realize the function of adjusting the bearing capacity and stiffness of the cantilever I-beam, and has the characteristics of high construction efficiency, good versatility, simple installation, good economy, and is conducive to saving construction costs.

[0009] The technical solution of the present invention is: a new type of cantilevered I-beam structure with adjustable bearing capacity and stiffness, comprising:

[0010] The I-beam main beam has one end located inside the floor slab and one end extending outside the floor slab. The end extending outside the floor slab is used as a platform for cantilever scaffolding to bear the cantilever load.

[0011] Supports are provided on the upper surface of the I-beam main beam and arranged in pairs along the longitudinal direction, with a total of three pairs, serving as anchors for the prestressed steel cables on the I-beam main beam;

[0012] The support rod is arranged in the longitudinal middle of the upper surface of the I-beam main beam and is perpendicular to the I-beam main beam. The support rod and the support are connected by prestressed steel cables;

[0013] Steel pads, used to fix the I-beam main beam and the support together with bolts, welded to the preset position on the upper surface of the I-beam main beam;

[0014] U-bolts are used to fix the I-beam main beam at specific positions on the inner side of the floor slab and at the brace;

[0015] There is only one pair of connection between the strut and the support at the same time, that is, there should be only two prestressed steel cables connecting the strut and two supports symmetrical about the strut at the same time.

[0016] The top of the strut structure includes an ear plate anchor for connecting the support through a prestressed steel cable; the bottom of the strut includes a steel pad with bolt holes for bolting and fixing the strut to the I-beam main beam and the floor concrete structure through the steel pad.

[0017] The I-beam main beam, the struts and the prestressed steel cables form a right triangle structure, with the I-beam main beam as the base, the struts arranged on the high line of the right triangle, and the prestressed steel cables arranged on the hypotenuse of the right triangle.

[0018] The load-bearing capacity is adjusted by adjusting the connection between the strut and the different pairs of supports, that is, when only one pair of supports is connected to the strut at the same time, the connected supports are switched to achieve the adjustment of the load-bearing capacity.

[0019] The prestressed steel cable exists as a cable and adopts a steel wire bundle, a steel strand, a steel wire rope or a steel pull rod. The prestressed steel cable is replaced when the connection support is switched, and the same prestressed steel cable is not used.

[0020] The adjustment of the stiffness is achieved by replacing the prestressed steel cable body, that is, when only one pair of supports are connected to the struts at the same time, the prestressed steel cable body is replaced to achieve the adjustment of the stiffness.

[0021] The method for using the novel beam string type cantilever I-beam structure with adjustable load-bearing capacity and stiffness comprises the following steps:

[0022] (1) Pre-embed the U-bolts to the corresponding positions of the floor slabs, and pour the floor slab concrete after acceptance;

[0023] (2) Install the steel pad and support to the I-beam main beam, and connect and fix the steel pad, support and main beam;

[0024] (3) Install the support rod, and connect and fix the support rod to the I-beam main beam;

[0025] (4) Install prestressed steel cables. Select appropriate prestressed steel cable bodies according to the bearing capacity and stiffness requirements, and connect the struts to a pair of supports using prestressed steel cables;

[0026] (5) Lift the cantilever I-beam as a whole to the predetermined floor level, install it to the designated position, and secure it with the pre-buried U-bolts;

[0027] (6) After acceptance, a cantilever scaffolding is set up on the side of the I-beam main beam extending out of the floor slab.

[0028] The present invention has the following beneficial effects:

[0029] 1. The present invention proposes a new structural solution, which forms a right-angled triangle structure by arranging struts, supports and prestressed steel cables. The tension of the prestressed steel cables and the supporting force of the struts can effectively enhance the bearing capacity and rigidity of the cantilevered I-beam.

[0030] 2. The present invention can also adjust the bearing capacity and stiffness according to different load conditions and stiffness requirements by switching the support connection and replacing the prestressed steel cable body. This adjustment function is not available in the prior art.

[0031] 3. The present invention has a simple structure, is easy to install and dismantle, has high construction efficiency, is economical, and is conducive to saving construction costs.

[0032] 4. Without relying on the support of the adjacent layer structure, the load of the cantilever end can be transferred to the floor slab of this layer. It does not involve artificial high-altitude outdoor operations, has good safety, and has high practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the side elevation of the installation of the I-beam of the present invention.

[0034] Figure 2 This is a schematic diagram of the front elevation of the I-beam installation of the present invention.

[0035] Figure 3 It is a schematic side elevation diagram of the support rod of the present invention.

[0036] Figure 4 It is a schematic diagram of the prestressed steel cable of the present invention.

[0037] Figure 5 It is a schematic side elevation diagram of the support of the present invention.

[0038] Figure 6 It is a top view of the support of the present invention.

[0039] Figure 7 It is a schematic diagram of the connection between the support and the I-beam of the present invention.

[0040] Marked in the figure: I-beam 1, strut 2, prestressed steel cable 3, support 4, U-bolt 5, ordinary bolt 6, steel pad 7. DETAILED DESCRIPTION

[0041] The present invention is further described below in conjunction with the accompanying drawings and embodiments. The embodiments are only a part of the present invention, not all of the embodiments, and are not intended to limit the present invention.

[0042] Example 1

[0043] like Figure 1 As shown, the novel tensioned beam type cantilever I-beam structure with adjustable bearing capacity and stiffness described in the present invention comprises an I-beam 1, a strut 2, a prestressed steel cable 3, a support 4, a U-bolt 5, a common bolt 6 and a steel pad 7. Among them, the U-bolt 5 is embedded in a preset position of the floor slab, and the strut 2 is arranged on the upper surface of the I-beam 1; one end of the I-beam 1 extends out of the floor slab, and the other end is limited by the U-bolt 5 and the steel pad 7; the support 4 in the floor slab is fixed to the upper surface of the I-beam 1 by the embedded U-bolt 5, which serves as an anchor of the prestressed steel cable 3 on the I-beam 1, and the U-bolt 5 here also plays a limiting role for the I-beam 1; the support 4 outside the floor slab is fixed to the upper surface of the I-beam 1 by ordinary bolts 6, which serves as an anchor of the prestressed steel cable 3 on the I-beam 1; one end of the prestressed steel cable 3 is connected to the ear plate anchor at the top of the strut 2, and the other end is connected to the upper surface of the I-beam 1 as a support 4 of the anchor.

[0044] The U-bolt pre-embedded position prepared for the support 4 can change the distance from the U-bolt used for the support rod according to the needs, or bury multiple U-bolts at the same time. The expected support 4 position and the U-bolt pre-embedded position used by it are already in Figure 1 It is marked with a dotted line in the middle, and during installation, multiple supports 4 can be installed at the same time or only the supports 4 that can meet the current bearing capacity requirements can be installed.

[0045] The I-beam 1, the strut 2 and the prestressed steel cable 3 form a right triangle structure, with the I-beam 1 as the base, the strut 2 arranged on the height line of the right triangle, and the prestressed steel cable 3 arranged on the hypotenuse of the right triangle.

[0046] There are a plurality of supports 4 , and the struts 2 and the supports 4 are connected in pairs, that is, there are two prestressed steel cables 3 respectively connecting the struts 2 and two symmetrical supports 4 of the struts 2 .

[0047] When the structural bearing capacity needs to be adjusted, the positions of the support 4 and the prestressed steel cable 3 used can be changed. For example, when the structural bearing capacity requirement becomes higher, the support 4 that is farther away from the support rod 2 can be switched, and a prestressed steel cable 3 of appropriate length can be used to increase the additional bearing capacity provided by the prestressed steel cable and enhance the structural bearing capacity.

[0048] When the structural stiffness needs to be adjusted, the cable body of the prestressed steel cable 3 can be changed. For example, if a steel wire rope is used originally and the structural stiffness requirement becomes higher, the cable body can be replaced with an equal-length steel strand with a larger diameter and higher stiffness.

[0049] The support rod 2 includes a pad 2-A, a rod body 2-B and an ear plate anchor 2-C. The rod body 2-B of the support rod 2 is arranged on the upper surface of the pad 2-A, and the two are connected by welding. The ear plate anchor 2-C is arranged at the top of the rod body 2-B. The pad 2-A is provided with bolt holes, and U-bolts 5 and ordinary bolts 6 are used to connect and fix it to the I-beam 1 and the floor concrete structure through the pad 2-A.

[0050] The support 4 includes an ear plate 4-A and a steel pad 4-B. The support 4 inside the floor is connected and fixed to the I-beam 1 and the concrete structure of the floor by using U-shaped bolts 5 through the steel pad 4-B. The support 4 outside the floor is connected and fixed to the I-beam 1 by using ordinary bolts 6 through the steel pad 4-B. The prestressed steel cable 3 is connected to the support 4 through the ear plate 4-A.

[0051] The method for using the novel beam string type cantilever I-beam structure with adjustable load-bearing capacity and stiffness comprises the following steps:

[0052] (1) Pre-embed the U-bolts to the corresponding positions of the floor slabs, and pour the floor slab concrete after acceptance;

[0053] (2) Install the steel pad and support to the I-beam main beam, and connect and fix the steel pad, support and main beam;

[0054] (3) Install the support rod, and connect and fix the support rod to the I-beam main beam;

[0055] (4) Install prestressed steel cables. Select appropriate prestressed steel cable bodies according to the bearing capacity and stiffness requirements, and connect the struts to a pair of supports using prestressed steel cables;

[0056] (5) Lift the cantilever I-beam as a whole to the predetermined floor level, install it to the designated position, and secure it with the pre-buried U-bolts;

[0057] (6) After acceptance, a cantilever scaffolding is set up on the side of the I-beam main beam extending out of the floor slab.

[0058] The technical principle of the load-bearing capacity adjustment of the present invention is as follows:

[0059] The height of the strut is H, and the distance between the strut and the support is L. After the prestressed steel cable with a tension force of N is installed, the additional bearing capacity P that it can provide for the structure is:

[0060]

[0061] Then, without changing the tension force N, the height H of the strut remains unchanged, and the connection between the strut and the support is switched to a pair of supports farther away from the strut, thereby increasing the distance L from the strut to the support, thereby increasing the additional bearing capacity P.

[0062] The technical principle of stiffness adjustment of the present invention is as follows:

[0063] After the prestressed steel cable is connected and fixed to the I-beam main beam through the support, the prestressed steel cable and the I-beam main beam form deformation coordination without failure of the whole structure. The tension of the prestressed steel cable increases the bearing capacity of the I-beam main beam while reducing the deflection of the I-beam main beam under the same load conditions, thereby improving the overall stiffness of the structure. Under the same load conditions, when the prestressed steel cable body is replaced (for example, from a steel wire rope with lower stiffness to a steel strand with higher stiffness), according to the principle of deformation coordination, the increase in the stiffness of a certain area inside the structure when it is stressed will increase the internal force in the area, that is, after replacing the high-rigidity cable body, the internal force of the prestressed steel cable increases, the internal force of the I-beam main beam decreases, the deflection of the I-beam main beam decreases, and the overall stiffness of the structure increases further; while replacing the low-rigidity cable body is the opposite, the internal force of the prestressed steel cable decreases, the internal force of the I-beam main beam increases, the deflection of the I-beam main beam increases, and the overall stiffness of the structure decreases.

[0064] The above embodiment is only a preferred implementation of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A novel cantilevered I-beam structure with adjustable load-bearing capacity and stiffness, characterized in that: include: The I-beam main beam has one end located inside the floor slab and one end extending outside the floor slab. The end extending outside the floor slab is used as a platform for cantilever scaffolding to bear the cantilever load. Supports are provided on the upper surface of the I-beam main beam and arranged in pairs along the longitudinal direction, with a total of three pairs, serving as anchors for the prestressed steel cables on the I-beam main beam; The support rod is arranged in the longitudinal middle of the upper surface of the I-beam main beam, is perpendicular to the I-beam main beam, and is connected to the support by the prestressed steel cable; Steel pads are used to fix the I-beam main beam and the support together with bolts, and can be welded to the preset position on the upper surface of the I-beam main beam; U-bolts are used to fix the I-beam main beam at specific positions on the inner side of the floor slab and at the brace; There is only one pair of connection between the strut and the support at the same time, that is, there should be only two prestressed steel cables connecting the strut and two supports symmetrical about the strut at the same time.

2. The novel beam string cantilever I-beam structure with adjustable load-bearing capacity and stiffness according to claim 1 is characterized in that: The top of the strut structure includes an ear plate anchor for connecting the strut and the support through a prestressed steel cable, and the bottom of the strut includes a steel pad with bolt holes for bolting and fixing the strut to the I-beam main beam and the floor concrete structure through the steel pad.

3. The novel beam string cantilever I-beam structure with adjustable load-bearing capacity and stiffness according to claim 1 is characterized in that: The I-beam main beam, the struts and the prestressed steel cables form a right triangle structure, with the I-beam main beam as the base, the struts arranged on the high line of the right triangle, and the prestressed steel cables arranged on the hypotenuse of the right triangle.

4. The novel beam string cantilever I-beam structure with adjustable load-bearing capacity and stiffness according to claim 1 is characterized in that: The bearing capacity is adjusted by adjusting the connection between the strut and the different pairs of supports. When only one pair of supports is connected to the strut at the same time, the connected supports are switched to adjust the bearing capacity. Assuming that the height of the strut is H and the distance from the strut to a pair of supports symmetrically arranged about the strut is L, after the prestressed steel cable with a tension force of N is installed, the additional bearing capacity P that the prestressed steel cable can provide for the structure is: Then, without changing the tension force N, the height H of the strut remains unchanged, and the connection between the strut and the support is switched to a pair of supports farther away from the strut, thereby increasing the distance L from the strut to the support, thereby increasing the additional bearing capacity P.

5. The novel beam string cantilever I-beam structure with adjustable load-bearing capacity and stiffness according to claim 1 is characterized in that: The prestressed steel cable is a steel wire bundle, a steel strand, a steel wire rope or a steel pull rod.

6. The novel beam string cantilever I-beam structure with adjustable load-bearing capacity and stiffness according to claim 1 is characterized in that: The adjustment of the stiffness is achieved by replacing the prestressed steel cable body. When only one pair of supports are connected to the struts, the prestressed steel cable body is replaced to achieve the adjustment of the stiffness. After the prestressed steel cable is connected and fixed to the I-beam main beam through the support, the prestressed steel cable and the I-beam main beam form deformation coordination without failure of the entire structure. The tensioning force of the prestressed steel cable increases the bearing capacity of the I-beam main beam, while reducing the deflection of the I-beam main beam under the same load conditions, thereby increasing the overall stiffness of the structure. Under the same load conditions, the prestressed steel cable body is replaced. According to the deformation coordination principle, the increase in the stiffness of a certain area inside the structure when it is subjected to force will increase the internal force in the area. After replacing the high-rigidity cable body, the internal force of the prestressed steel cable increases, the internal force of the I-beam main beam decreases, the deflection of the I-beam main beam decreases, and the overall stiffness of the structure further increases; while replacing the low-rigidity cable body is the opposite, the internal force of the prestressed steel cable decreases, the internal force of the I-beam main beam increases, the deflection of the I-beam main beam increases, and the overall stiffness of the structure decreases.

7. The method for using the novel beam string cantilever I-beam structure with adjustable load-bearing capacity and stiffness according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Pre-embed the U-bolts to the corresponding positions of the floor slabs, and pour the floor slab concrete after acceptance; (2) Install the steel pad and support to the I-beam main beam, and connect and fix the steel pad, support and main beam; (3) Install the support rod, and connect and fix the support rod to the I-beam main beam; (4) Install the prestressed steel cable. According to the bearing capacity and stiffness requirements, select a suitable prestressed steel cable body, and connect the support rod and a pair of supports using the prestressed steel cable; (5) Lift the cantilever I-beam as a whole to the predetermined floor level, install it to the designated position, and secure it with the pre-buried U-bolts; (6) After acceptance, a cantilever scaffolding is set up on the side of the I-beam main beam extending out of the floor slab.

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