JPS628270Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a reinforced concrete beam member. In general, beam members of buildings that are subjected to bending moments and shear forces have, in addition to tensile compressive stress A and shear stress B due to bending moments, diagonal tensile stress that is a composite stress of tensile compressive stress and shear stress, as shown in Figure 1. It is known that the direction of this diagonal tensile stress C is approximately horizontal C' at the center of the beam member, and becomes inclined C'' as it approaches the ends. Stress C poses no problem in beam members such as steel beams, where the tensile and compressive strengths can be assumed to be approximately equal, but in reinforced concrete beam members, the tensile and shear strengths are less than one-tenth of the compressive strength. In many cases, diagonal cracks occur before the compression of the tension reinforcing bars or the compression side concrete, causing fracture.''For this reason, in conventional reinforced concrete beam members, the main reinforcement is In addition to the stirrup reinforcements E, bent reinforcing bars and stirrup reinforcements are specially arranged at the end of the beam to resist the diagonal tensile stress. However, this bent reinforcing bar F is made by bending down or bending a part of the main reinforcement with a relatively large diameter, and the effect is extremely large if multiple reinforcements are placed over the entire end of the beam at appropriate intervals. However, since the bending process of the bent reinforcing bar is extremely troublesome, the diagonal tensile stress C
The current situation is that reinforcement is placed only at the outer end where the maximum value is achieved, and in other areas, a large number of stirrup reinforcements are placed at small intervals.

This method of reinforcing diagonal tensile stress by combining bent reinforcing bars and stirrup bars involves processing and assembling the reinforcing bars on site, which causes a decrease in work efficiency, and also causes variations in the degree of reinforcement depending on the assembly state. However, this method had the disadvantage of increasing costs due to an increase in the amount of reinforcing bars used.

This idea was proposed to solve the above-mentioned conventional problems, and instead of arranging bent reinforcing bars at both ends of a reinforced concrete beam member, a wire mesh such as a welded wire mesh or a lath wire mesh is arranged over a certain range. In addition to effectively resisting the diagonal tensile stress C using this wire mesh, it also greatly simplifies various operations such as processing reinforcing bars and assembling reinforcing bars on site, and also significantly saves the amount of reinforcing bars such as stirrup bars. The purpose is to

Hereinafter, this invention will be explained in detail with reference to an embodiment shown in the drawings. In FIGS. 3 and 4, reference numeral 1 indicates a reinforced concrete beam member according to this invention, and reference numeral 2
Reference numeral 3 indicates the upper main reinforcing bars arranged in the longitudinal direction of the beam, numeral 3 indicates the lower end main reinforcing bars arranged in the same way, and numeral 4 indicates the stirrup reinforcements that bundle these main reinforcements. These upper end main reinforcements 2, 2, lower end main reinforcements 3, 3, stirrup reinforcements 4, . . . are arranged in required numbers at predetermined positions by a conventional reinforcement arrangement method.

Between the upper end main reinforcements 2, 2 and the lower end main reinforcements 3, 3 at both ends of the reinforced concrete beam member 1, wire meshes 5, 5 with a fixed mesh made of welded wire mesh, sluice wire mesh, etc. include the part where the diagonal tensile stress is maximum. It is buried over almost the entire area. The wire meshes 5, 5 need to have a mechanical structure that is strong against tensile force in the diagonal direction, and preferably have a diamond-shaped mesh structure in which wires are stretched diagonally. It is also necessary that the meshes be fixed, such as by welding or tightly bonding, at the intersections of the meshes. The wire mesh having such a structure is arranged vertically to the beam in its longitudinal direction, but as shown in Fig. 5,
When arranging not only one sheet but a plurality of sheets, it is preferable to arrange them in a row approximately parallel to each other with appropriate spacing in the width direction of the beam as shown in FIGS. 3 and 4. Although the length of the wire mesh may be arranged over the entire length of the beam, it is preferable that the wire mesh is always buried at least at both left and right ends of the beam.

By configuring the present invention as described above,
The wire meshes 5, 5 effectively resist the diagonal tensile stress generated at the ends of the beams, and damage accidents such as cracking can be prevented. In this case, if a wire mesh with a diamond-shaped mesh is used, the reinforcing effect will be doubled because the directions of the material forming the wire mesh and the diagonal tensile stress will be substantially the same. Furthermore, since it can be effectively reinforced against diagonal tensile stress, the reinforcing effect of the main reinforcement against edge stress is also increased.

This design consists of the above structure, so it can be applied not only to the part of the beam where the diagonal tensile stress due to normal loads is the greatest, but also to the entire beam area against diagonal tensile stress due to emergency loads such as earthquakes, storms, or explosion pressure. It can be reinforced very effectively.

In addition, since bent rebar is not required during construction, various tasks such as processing and assembling rebar on site can be greatly simplified, and the spacing between the star wrap bars at the beam ends can be increased, resulting in a significant saving in the amount of rebar used.

[Brief explanation of drawings]

Figure 1 is a front view of a beam member showing the direction of principal stress when subjected to load P, Figure 2 is a sectional view of a conventional reinforced concrete beam member, Figure 3 is a perspective view of the end of a reinforced concrete beam member, and Figure 3 is a perspective view of the end of a reinforced concrete beam member. 4 and 5 are cross-sectional views of the end or central portion of the reinforced concrete beam member, and FIG. 6 is a vertical cross-sectional view of the end portion. 1... Reinforced concrete beam member, 2... Top end reinforcement, 3... Bottom end reinforcement, 4... Starlap reinforcement, 5...
...wire mesh.

Claims (1)

[Claims for Utility Model Registration] 1. In a reinforced concrete beam member formed by arranging a plurality of main reinforcements and stirrup reinforcements at predetermined positions in concrete, a mesh is fixed between the main reinforcements at least at the ends of the reinforced concrete beam member. A reinforced concrete beam member characterized by vertically buried wire mesh. 2. The reinforced concrete beam member according to claim 1 of the utility model registration claim, characterized in that a wire mesh with a fixed mesh is buried only at the end of the beam. 3. The reinforced concrete beam member according to claim 1 of the utility model registration claim, characterized in that a wire mesh is embedded over the entire length of the beam. 4. The reinforced concrete beam member according to claim 1 of the utility model registration claim, characterized in that a plurality of wire meshes are embedded.