CN102561592A - Retarded adhesive prestressed lattice type steel reinforced concrete beam - Google Patents

Abstract

The invention relates to a hollow steel-reinforced concrete beam, which belongs to the field of civil engineering. A slowly bonded prestressed hollow steel-reinforced concrete beam, comprising a concrete beam (1), the hollow steel framework (4) is arranged inside the concrete beam (1), and non- The prestressed tendons (2) are bound with stirrups (3) outside the non-prestressed tendons (2), and are characterized in that: the hollow steel frame (4) includes four-corner angle steels, which pass through the concrete beam near the lower angle steels (1) Slowly bonded prestressed tendons (5) are provided, and the slow bonded prestressed tendons (5) are wrapped with retarded mortar (8) outside the prestressed tendons (7). The mode of wrapping with impermeable plastic cloth (9) outside again. The invention adopts slow bonded prestressed tendons for tensioning, so that the structure of the concrete beam has light weight, simple construction, and has the characteristics of high bending ultimate bearing capacity, which is beneficial to the popularization and application of the hollow steel reinforced concrete beam.

Description

Slow Bonded Prestressed Vierendeel Steel Reinforced Concrete Beams

technical field

The invention relates to a hollow steel-reinforced concrete beam, in particular to a slow bonded prestressed hollow steel-reinforced concrete beam.

Background technique

The hollow steel-reinforced concrete structure is a composite structure in which the space truss steel frame formed by connecting angle steel with patch plates is embedded inside the reinforced concrete. The space truss steel frame has good constraints on the core concrete, so that the ultimate compression deformation of the core concrete, The compressive strength and rigidity are improved. However, in some cases that require high structural rigidity, crack and deformation control is often difficult to meet the requirements. Therefore, the prestressed hollow steel-reinforced concrete structure came into being, which is to apply prestress in the hollow steel-reinforced concrete structure, so as to improve the crack resistance and deformation resistance of the structure. On the other hand, compared with the prestressed solid-web steel reinforced concrete structure, the prestressed tendon layout is less restricted and the construction is more convenient in the hollow steel reinforced concrete structure.

In recent years, two forms of tendons, bonded prestressed tendons and unbonded prestressed tendons, have been used for tensioning in prestressed steel reinforced concrete structures. For prestressed steel-reinforced concrete structures with bonded tendons, due to the need to reserve tunnels, reinforcements, grouting and other processes during the construction process, this leads to complex construction and slow speed, and the prestressed tendons are easy to corrode and have broken wires However, for prestressed steel-reinforced concrete structures without bonded bars, the above-mentioned defects can be improved, but the ultimate flexural bearing capacity will be reduced by 10%-20%. Therefore, a new prestressed steel reinforced concrete structure with simple construction and reliable performance can be developed to overcome the above defects, and promote the promotion and application of prestressed hollow steel reinforced concrete structures in engineering economically and technically.

Contents of the invention

The technical problem to be solved by the present invention is to provide a slow bonded prestressed open-web steel reinforced concrete beam, which solves the defects of complex construction, slow speed, unsatisfactory service performance or ultimate bending bearing capacity in the prior art.

Technical solutions

A slowly bonded prestressed hollow steel reinforced concrete beam, comprising a concrete beam, the hollow steel framework is arranged inside the concrete beam, non-prestressed tendons are arranged around the hollow steel framework, and the non-prestressed tendons are bound and installed outside the non-prestressed tendons There are stirrups, which are characterized in that: the hollow type steel frame includes four-corner angle steel, and a slow-bonding prestressed tendon is set through the concrete beam near the lower angle steel, and the slow-bonding prestressed tendon is wrapped outside the prestressed tendon The slow-setting mortar is wrapped with impermeable plastic cloth outside the slow-setting mortar.

The slow bonded prestressed tendon passes through the concrete beam and is fixed on the concrete beam with an anchor device.

The four angle steels of the hollow steel frame are symmetrically arranged in the middle of the concrete beam section.

There are two slow-bonding prestressed tendons installed on the inside of the lower angle steel of the hollow steel frame.

Beneficial effect

The slow-bonding prestressed hollow steel-reinforced concrete beam of the present invention adopts slow-bonding prestressed tendons for tensioning, so that the concrete beam has the disadvantages of light weight, simple construction and fast speed of the unbonded prestressed steel concrete beam. , and has the characteristics of high flexural ultimate bearing capacity of bonded prestressed steel reinforced concrete beams, which is conducive to the promotion and application of slow bonded prestressed hollow steel reinforced concrete beams in actual engineering.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the present invention.

Fig. 2 is a schematic cross-sectional view of the structure of the present invention.

Fig. 3 is a sectional view of slow bonded prestressed tendons in the structure of the present invention.

Among them: 1-concrete beam, 2-non-prestressed tendons, 3-stirrup bars, 4-empty belly steel frame, 5-slowly bonded prestressed tendons, 6-anchor device, 7-prestressed steel bars, 8-retarded setting Mortar, 9 - impermeable plastic sheeting.

Detailed ways

Below in conjunction with specific embodiment, further illustrate the present invention.

The present invention proposes a slowly bonded prestressed hollow steel reinforced concrete beam, comprising a concrete beam 1, the hollow steel framework 4 is arranged inside the concrete beam 1, and non-prestressed tendons 2 are arranged around the hollow steel framework 4 , a stirrup 3 is bound outside the non-prestressed tendon 2, and the hollow type steel frame 4 includes four-corner angle steels, and a slow-bonding prestressing tendon 5 is provided through the concrete beam 1 near the lower angle steels, and the slow-bonding The prestressed tendon 5 adopts the method of wrapping the retarded mortar 8 outside the prestressed tendon 7, and wrapping the retarded mortar 8 with a water-impermeable plastic cloth 9.

The slow-bonded prestressed tendon 5 passes through the concrete beam 1 and is fixed on the concrete beam 1 with an anchor device 6 .

The four angle steels of the hollow steel frame 4 are symmetrically arranged in the middle of the section of the concrete beam 1 .

There are two slow-bonding prestressed tendons 5 installed on the inner side of the lower angle steel of the hollow steel frame 4 .

The structure of the present invention can be realized in the following ways: during construction, the concrete beam 1 beam bottom formwork is first laid, and after the reinforcement verification, the supporting iron parts of the hollow type steel frame 4 are placed on the beam bottom formwork, and the four parts of the hollow type steel frame 4 are placed After the two angle steels are installed respectively, the non-prestressed steel bars 2 and stirrups 3 on the beam are bound, and then the slow bonded prestressed bars 5 are pierced, and then the beam side formwork is supported, and the concrete is poured until the concrete reaches a certain strength (not lower than the design strength). 75% of the strength), use a jack to carry out prestress tension on the slow bonded prestressed tendons 5, after the stretching is completed, fix the slow bonded prestressed tendons 5 with an anchor device 6, and perform sealing protection, and finally remove the formwork. The whole process is simple and clear, greatly improving the construction speed.

The slow-bonding prestressed hollow steel-reinforced concrete beam adopts slow-bonding prestressed tendons 5 for tensioning in the fasting steel-reinforced concrete beam, and wraps a layer of slow-setting mortar 8 around the surface of the prestressed tendons 7 and then Wrapped with plastic cloth 9, it has the characteristics of easy construction of the unbonded structure before the prestressed tendons are stretched, and has the characteristics of high bending ultimate bearing capacity of the bonded prestressed tendons structure in the later stage. It has been confirmed by experimental research that the structure has the following advantages:

(1) The structure is light in weight. Due to the slow bonded prestressed tendon 5, the beam does not need to reserve a hole, the size is reduced, and the self-weight is reduced, which is conducive to reducing the load of the lower support column and reducing the cost.

(2) The construction is simple and fast. During construction, the slowly bonded prestressed tendons 5 are laid in the formwork according to the design requirements, and then concrete is poured. After the concrete reaches a certain strength, it is stretched, anchored, and the end is blocked. It does not require complex procedures such as reserving channels, threading reinforcement, and grouting, which simplifies the construction process and speeds up the construction progress.

(3) The bending ultimate bearing capacity is high. After the completion of the construction, after the specified time, the retarding material in the slow-bonding prestressed tendons 5 begins to harden and reaches a considerable bonding and compressive strength, which wraps and protects the prestressed tendons 7, so that the prestressed tendons 7 and Concrete components are bonded together, and there is a deformation coordination relationship between them.

In the construction process, the present invention does not need to reserve holes, thread reinforcement, and grout after tensioning, etc., which greatly simplifies the construction process, reduces the self-weight of the structure during use, and overcomes the limit of unbonded prestressed steel concrete beams The shortcomings of low bending capacity, good performance, good economy and applicability.

Claims (4)

1. A slow bonding prestressed hollow type steel reinforced concrete beam, comprising a concrete beam (1), the hollow type steel frame (4) is arranged in the described concrete beam (1), and the hollow type steel frame (4) is arranged around There are non-prestressed tendons (2), and stirrups (3) are bound and installed outside the non-prestressed tendons (2). It is characterized in that: the hollow steel frame (4) includes four-corner angle steels, which pass through the lower angle steels. The concrete beam (1) is provided with slow-bonded prestressed tendons (5), and the slow-bonded prestressed tendons (5) are wrapped with slow-setting mortar (8) outside the pre-stressed tendons (7), and the slow-setting mortar ( 8) wrapping with impermeable plastic cloth (9) outside again. 2. The slow bonding prestressed hollow steel reinforced concrete beam as claimed in claim 1, characterized in that: the slow bonding prestressed tendon (5) passes through the concrete beam (1), and the anchoring device (6) fixed on the concrete beam (1). 3. The slow bonding prestressed hollow steel reinforced concrete beam as claimed in claim 1 or 2, characterized in that: the four angle steels of the hollow steel framework (4) are symmetrically arranged on the concrete beam (1 ) in the middle of the section. 4. as claimed in claim 1 or 2 described slow bonded prestressed hollow type steel reinforced concrete beam, it is characterized in that: described slow bonded prestressed tendon (5) is provided with two, is installed in hollow type steel frame ( 4) The inner side of the lower angle steel.

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