JPH03217528A - Construction of multi-layer steel frame and steel-framed reinforced concrete structure - Google Patents

Abstract

PURPOSE:To relieve the deflexion of the central spanned part by a method in which the steel framed beam, whose span center is divided into two sections and jointed and an upward load is applied to the joint to cause deflection, is rigid-jointed with steel columns, and the load is removed. CONSTITUTION:A steel column 1 and a steel framed beam 2 are made of H- steel. The beam 2 is divided into two sections at the center of span, and the divided beams 2a are shaped into a circular arc face 2b and joined with each other through a joint plate 3 and a joint pin 4 to form a pin-joint 6. They are rigid-joined with the steel column 1 in the horizontal attitude. An upward load P is applied by jacks, etc., to the center of span to cause upward deflection near the joints 6, and under the condition the beams 2 so divided are rigid- jointed with each other to remove the load P. The deflexion in the central span of the beams 2 can thus be relieved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improved erection method for multi-layer steel frames and steel reinforced concrete structures.

(Prior art) In multi-story steel frames and steel-frame reinforced concrete structures that form the framework of high-rise buildings, columns and beams are made of H-shaped steel, etc., and beams are connected between the columns to form a multi-story structure. The framework of the structure is being erected.

In this kind of multi-story steel frame and steel reinforced concrete structure,
Conventionally, the cross-sectional dimensions of the central part of the beam are determined with the highest priority being to keep the amount of deflection that occurs in the beam material due to vertical loads within a certain standard value, and then the cross-sectional dimensions of the entire frame member are determined based on this. Moreover, the columns and beams are assembled into a rigid structure from the beginning by bolting or welding.

(Problems to be Solved by the Invention) According to the conventional design method of member dimensions, each beam material has a very large stress in response to the expected vertical load and horizontal load during an earthquake in terms of strength. It is uneconomical because it has a sufficient margin and has a structure that is too strong.

The present invention has been proposed in view of the problems of the prior art, and its purpose is to safely determine the cross-sectional dimensions of structural members within a range that satisfies the necessary conditions for structural design. The object of the present invention is to provide a construction method for multi-layer steel frames and steel-frame reinforced concrete structures that can reduce the weight of the structures.

(Means for Solving the Problems) In order to achieve the above object, according to the method for constructing a multi-layer steel frame and steel-frame reinforced concrete structure according to the present invention, a steel beam connected between a plurality of steel columns is The divided steel beams are divided into two parts with a slight gap maintained between them, and the opposing ends of each divided steel beam are joined via pin joints, and each end of the divided steel beams thus pin-joined is connected to the The steel beam is rigidly connected to a steel column in a horizontal position, and then an upward load is applied to the steel beam near the center of its span to cause the steel beam to undergo a predetermined upward deflection, and in this state, each of the divided steel beams is This is to rigidly connect them and then remove the upward load.

(Function) According to the present invention, as described above, the steel beams of each floor connected between a plurality of steel columns are divided into two parts with a slight gap maintained at the center of the span, and the steel beams are divided in this way. By connecting the opposite ends of each steel beam through a pin joint, and rigidly connecting each end of each of the split steel beams thus pin-connected to the steel column in a horizontal position, each floor can be A multi-story steel frame is constructed with a pin structure at the center of the span of the steel beams.

Therefore, if an upward load is applied near the center of the span of a steel beam in the same frame, the center of the span of the steel beam will be deflected upward due to a much smaller load than if the same section had a rigid structure. can.

In this way, an upward load is applied to the center of the steel beam for each floor, and when the stress change in the steel beam reaches a certain value, for example, a value corresponding to the stress generated by the vertical load when the frame is completed, the above-mentioned After the split steel beams around the pin joints are rigidly connected to each other and the upward load is removed, compressive prestress is introduced to the upper edge of the steel beam, and tension prestress is introduced to the lower edge of the steel beam. .

The prestresses introduced into the steel beam give a deflection in the direction opposite to the stress direction caused by the vertical load applied to the steel beam, so the vertical load causes the center of the span of the steel beam to bend. The amount of deflection in the same area is significantly reduced.

(Example) The present invention will be described below with reference to some embodiments.

FIG. 1 is a diagram showing a bridge surface of an embodiment of a multi-layer steel frame or steel-frame reinforced concrete structure constructed by the method of the present invention. (1) shows a steel column made of H-shaped steel, (2) is a steel beam made of H-shaped steel, etc., which will be constructed on multiple floors between the same steel columns (1).

The steel beam (2) is divided into two parts so that a gap is formed at the center of the span, and the opposing ends of the two divided steel beams (2a) form an arcuate surface (2b) that bulges toward the other member. is formed.

Of the pair of opposing split steel beams (2a),
The base ends of a pair of front and back joint plates (3) (3) are welded (b) to the web part of one split steel beam (2a), and each joint plate (2a) is
3) The other split steel beam (2
The connecting pin (5) that passes through the large diameter connecting hole (4) drilled in the web portion of a) is inserted into the protruding tip of the pair of connecting plates (3) (3). A pin joint (6) is formed at the center of the span of the steel beam (2). (See Figures 2 and 3) The pin joints of the steel beams (2) are constructed using various methods other than those in the above embodiments, and the split steel beams (2) are constructed using various methods.
2a) It is sufficient if (2a) is configured to allow rotation equivalent to that of a pin at the center of the span of the steel beam (2). Opposite ends of the left and right split steel beams (2a) (2a>) are pin-joined on the frame, and the other end of each split steel beam (2a) is bolted to the steel column (1) in a horizontal position. , the two split steel beams (2a) are rigidly connected by welding or the like or are pin-connected.
(2a) is suspended and rigidly connected to the steel column (1) in a horizontal position in the same manner as described above. In the figure, (7) is the rigid joint between the column and beam.

Next, an upward load P is applied near the center of the span of the beam material (2) by jacking or lifting,
As shown in FIG. 4, an upward deflection is caused near the pin joint (6) at the center of the span of the steel frame (2).

At this time, by rotating the left and right split steel beams (2a) around the pin joint (6), the span center of the steel beam (2) is smaller than when one continuous beam is bent. Deflection easily occurs when a much smaller load is applied.

In addition, a strain gauge is installed at the nearest position near the steel column (1) to which the steel beam (2) and the steel column (2) are rigidly connected. The upward load P is applied while monitoring the stress change.

As shown in the fifth circle, when the stress exceeds a certain stress corresponding to the maximum allowable stress depending on the length of the steel beam (2), The protruding end portion is welded to the web portion of the split steel beam (2a), and the arcuate surface (2b) of the opposing split steel beam (2a) (2a)
) (2b) Insert the connecting plate (8) between them, fill the gap, and connect each beam (
The upper flanges (2a1) (2a.) and lower flanges (2a-) (2a-) of 2a) are welded to connect the left and right split steel frames (2a) (2a) rigidly.

In this state, the steel column (1) and the steel beam (2) have a rigid structure, and when the upward load P is released, the stress generated in the steel beam (2) by the same load P causes the (
2) Compressive prestress is introduced inside on the upper edge side and tensile stress is introduced on the lower edge side.

By sequentially repeating such construction from the lower layer steel beam material (2) to the upper layer steel beam material (2) in FIG. 1, a rigid multi-layer steel structure of a desired floor is constructed.

According to the method shown in the above embodiment, prestress can be safely and easily introduced into structural members with high rigidity that are difficult to cause deflection during the erection stage, and in the assembled steel structure, the vertical load can be applied to each floor. The deflection is significantly reduced, and within the limits of the allowable deflection, the cross section of the steel beam can be reduced and the weight can be significantly reduced, and the required prestress in the opposite direction can be easily introduced into the steel column. It is possible to reduce the cross section of the column and reduce its weight.

(Effects of the Invention) According to the present invention, as described above, when constructing a multi-story steel structure, the steel beams of each story are divided into two with a slight gap maintained at the center of the span, and each divided steel beam is After joining the opposing ends of the beams via a pin joint, and rigidly joining both ends of the pin-joined split steel beam to the steel column in a horizontal position,
Usually, by applying an upward load in the opposite direction to the design load to the center of the span of the steel beam to cause the steel beam to deflect upward, and in this state, rigidly joining the center part of the split steel beam, It is very difficult to cause deflection and it is necessary to apply a very large load to a rigid steel beam. During the erection stage, we can safely and easily calculate the required amount of deflection in the opposite direction by applying a small load. In this state, by rigidly joining the split steel beams at the center of the span, the steel column constructed according to the present invention can easily receive prestress in the required opposite direction. By reducing the cross-section of the steel beam, it becomes possible to design a structurally rational and economical multi-layer steel frame or steel-frame reinforced concrete structure.

[Brief explanation of drawings]

1 is a front view V diagrammatically showing a bridge surface of a multi-layer steel frame or steel-frame reinforced concrete structure constructed by the method of the present invention; FIG. FIG. 3 is a partially cut-out view of the second arrow view ■-■. FIGS. 4 and 5 are front views showing the construction process of the pin joint. (1) Steel column, (2) Steel beam, (2a) Split steel beam, (3) Joint plate, (4) Connection hole, (5) ...Joining pin, (6)...Pin joint, (force...
Rigid joint, (8)...Connecting plate, (wl(
w'l...Welded part, P...Upward load.

Claims (1)

[Claims] In a construction method for multi-story steel frames and steel-framed reinforced concrete structures in which steel beams are connected between multiple steel columns in a multi-story manner, the steel beams are divided into two parts with a slight gap maintained at the center of the span. Opposite ends of the split steel beams are joined via pin joints, each end of the split steel beams thus pin-joined is rigidly joined to the steel column in a horizontal position, and then the span of the steel beams is An upward load is applied near the center to cause the steel beam to undergo a predetermined upward deflection, and in this state, each of the divided steel beams is rigidly connected at the center of the span, and then the upward load is removed. Features a construction method for multi-layer steel frames and steel-framed reinforced concrete structures.