JPH0363340A - Controlling method of flexibility of large span skeleton - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for controlling deflection of a beam in a large span frame.

(Prior Art) Large span frames are used for structures such as indoor stadiums and large hangars that do not have intermediate columns.

Since these structures support truss shop model beams with large spans of 100 m to 200 m at both ends, there is a problem in that the steel beams bend downward due to vertical loads such as their own weight.

Therefore, in recent years, the following two methods have been proposed as a method for controlling this deflection, that is, as a typical method for adding "bulge" to the beam M as shown in FIGS. 4 and 5.

First, as shown in FIG. 4, by applying a horizontal force P to the pillars of both pillars 5 inwardly facing each other, the beam M shown by the dotted line is forced to create a "muscle" shown by the solid line. This is a method of giving chestnut J.

Second, as shown in FIG. 5, by tensioning a high-tensile steel wire (not shown) along the lower chord member 6 of the beam M from both ends, the beam M shown by the dotted line has the shape shown by the solid line. This is a method of giving ``mukuri''.

(Problem to be Solved by the Invention) However, the first method among the above methods requires moving work by applying a horizontal force and fixing work while applying a large horizontal force, so the work process is slow. Not only is this complicated, but it also requires a special reaction force device to apply horizontal force to the column base, and there are also problems in that the foundation becomes large and construction costs increase.

In the second method, high-tensile steel wires are incorporated into the beam, so
There were problems in that it was difficult to construct and, like the above, the construction cost increased.

The present invention has been made in view of the above-mentioned problems, and its purpose is to control the deflection of a large-span frame by simply and inexpensively providing a curve to the beam in the large-span frame. The object of the present invention is to provide a control method.

(Means for achieving the above objects) The configuration of the present invention as a means for achieving the above objects is as follows.
A large-span frame is formed by installing columns at both ends of a beam whose lower chord is shorter than the pre-calculated length of the lower chord, and when assembling the large-span frame, the beam is supported in the vertical direction with temporary support stands, and the columns are The present invention resides in a method for controlling deflection of a large span frame, which comprises supporting the legs with movable sliding bearings and then removing the temporary support base.

(Function) According to the above configuration, by making the lower chord of the beam shorter than the pre-calculated length of the lower chord, a large span frame is formed in which the beam is curved vertically upward in advance. ,
When assembling the large span frame, the beams are supported by temporary supports and the columns are supported by sliding bearings, and the temporary supports are removed after the large span frame is assembled, so that the beams are free from their own weight and live load. As a downward vertical load is applied, the column base on the sliding bearing side moves outward and the bottom chord reaches the pre-calculated length, forming the large-span frame into the pre-designed shape and controlling deflection. can do.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

Figure 1 is a front view of a large-span frame A, which is composed of columns 2 joined to both ends of a truss-shaped beam 1 composed of an upper chord member 1a, a lower chord member 1b, and a bundle or diagonal member 1c. .

Since the lower chord member 1b of the beam 1 is formed to be shorter than the pre-calculated length of the lower chord member 1d, the beam 1 is formed with an upward vertical force, that is, an upward curve, as shown in Fig. 1. has been done.

In addition, a slide support 3 is attached to the lower end of one of the pillars 2 provided at both ends of the beam 1, and is formed to be movable. Open.

Note that this sliding support 4 may optionally be provided at both ends or one end of both pillars 2 or beams 1, and in either case, the pillars 2 and beams 1 move outward in the same manner as described above.

When assembling the large span frame mA, the pillars 2 are assembled with the beams 1 supported by the support frames 4, as shown in FIG. At this time, the steel beam 1 has a lower chord member 1b calculated in advance.
Because it is shorter than the length of , it is assembled in an upwardly curved state, and both pillars 2 are also fixed in an inwardly inclined state.

Then, both of these columns 2 are fixed to form a large span frame A.
By removing the support pedestal 4 after the support frame 4 is assembled, a downward vertical load such as its own weight is applied to the beam 1, so that the column 2 on which the sliding support 3 is installed is expanded outward, as shown in FIG. It is formed into a pre-designed shape as shown by the dotted line.

In addition, if the sliding bearing 3 is not provided on the pillar 2 as described above but is provided on both ends or one end of the beam 1, the end of the beam 1 is supported by the support pedestal 4, and then the support pedestal 4 is removed. The same effect as above can be obtained.

In Figure 2, the upper and lower chords are 350X350X12X19
(All units below are mm) HfR, the column is 900
This figure shows a large span frame A made of H steel of X3QOχ16X2.9 and the members used therein, which were formed into a planned shape calculated in advance by analyzing this.

In this case, the length of the lower chord member 1b in FIG. 2 is 10 cm shorter than the previously calculated length of the lower chord member 1d in FIG.

Taking this result into consideration in terms of construction, the large span frame IA can be constructed by assembling the large span frame A having the shape shown in Figure 2, supporting the beam 1 with the support frame 4, and removing the support frame 4 after the assembly is completed. As shown in FIG. 3, it was possible to prove that the film was formed into the pre-calculated planned shape, and the following effects were confirmed.

(Effects of the Invention) The present invention has the following effects by having the above configuration. ′ ■ A large-span frame is formed by installing columns at both ends of a beam whose lower chord is shorter than the pre-calculated length of the lower chord, and when assembling the large-span frame, the beam is oriented vertically with temporary supports, By fixing the column with a movable sliding bearing and then removing the temporary support base, the column expands outward due to the beam's own weight, so the large span frame is formed into a pre-designed shape and bends. can be easily controlled.

■ By providing a sliding bearing at the lower end of the column, no stress is applied, and deflection can be controlled without the need for external force.

[Brief explanation of drawings]

Figures 1 to 3 are front views showing how the method for controlling deflection of a large span frame according to the present invention is implemented, and Figures 4 and 5 show how the conventional method for controlling deflection of a large span frame is implemented. It is a front view. A: Large span frame 1: Beam la: Upper chord member 1b: Lower chord member 1d: Lower chord member calculated in advance 2: Column 3: Sliding support 4: Support frame

Claims (1)

[Claims] A large span frame is formed by providing columns at both ends of a beam whose lower chord is shorter than the pre-calculated length of the lower chord, and when assembling the large span frame, the beam is supported in the vertical direction by temporary support stands, and A method for controlling deflection of a large-span frame, comprising supporting a column base with a movable sliding support, and then removing the temporary support base.