JPH0313606A - Construction method and apparatus for structure - Google Patents

Abstract

PURPOSE:To reduce or eliminate the amount of stretch material required during execution and the operation man hour by providing an eccentric position moving device and a tension adjusting device to move a stretch material up and down according to the change of working moment in each execution stage. CONSTITUTION:Cable eccentric jacks 1 are sequentially installed on the upper surface of a supporting point of a structure 2 and the upper surface of the center between supports with the progress of execution, and a tension adjusting jack 3 is installed on the forward end portion of an out cable 6 to secure a designated cable eccentricity and tension force, so that according to a design value, the jacks 1, 3 interlock with each other. During extruding execution, the cable 6 is repeatedly moved up and down by the jacks 1 in such a manner as to be downward in the section in the central portion between supports and be upward in the section on the supporting point. In response to the state of working moment in each execution stage, the arrangement form of the cable 6 is changed, and the cable is coated with a cover 7 in a complete system and fixed to a web by an anchor bolt.

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention is applicable to the construction of structures where the structural system changes during construction, such as the extrusion method, or construction where the stresses at the time of erection and completion are reversed. The present invention relates to a method and apparatus for constructing a structure using an eccentric movement method using an out-cable method, which can be used, for example, for the rotational erection of girders and the demolition of structures such as bridges.

(Prior Art) Conventionally, in prestressed concrete structures, an inner cable method in which tension members are placed inside a concrete member has been mainstream.

(Problem B to be solved by the invention) By the way, in the conventional method described above, the position of the tension material is fixed inside the member, so it can be said that it is unsuitable for members where the acting moment fluctuates during erection and the positive and negative changes may be reversed. . In other words, the eccentric position of the tendon sometimes has the opposite effect, and the current situation is that it must be dealt with by methods such as axial center placement. As a result, unnecessary cables remain at the time of completion, making it very uneconomical. Moreover, if over-prestress occurs in the completed system, it becomes necessary to release the tension, which is disadvantageous not only in terms of materials but also in terms of labor.

This invention was developed in order to solve the conventional difficulties, and it provides a construction method and device that can reduce or eliminate the amount of tension material during construction that is unnecessary in the completed system and the associated work effort. The purpose is to provide.

(Means for Solving the Problems) In order to achieve the above-mentioned object, in this invention, a part or all of the tension material is arranged as an out cable, and the position of the out cable is moved vertically as needed by an eccentric position moving device. , and a predetermined tension is maintained at the same time by a tension adjustment device against the accompanying length variation of the tendon material.

The eccentric moving device consists of a cable eccentric jack, which is installed on the top surface of the structure.
Further, the tension adjustment device includes a tension adjustment jack, and this tension adjustment jack is installed at the end of the tendon.

(Example) The present invention will be described below based on an illustrated example of the extrusion method. 1 to 3 show a cable eccentric position moving device and a cable tension adjusting device used in the present invention, and the structure of the resetting device basically consists of a hydraulic jack. Then, as an eccentric position moving device, a cable eccentric jack l is placed on the upper surface of the fulcrum of the structure 2,
and the upper surface of the center of the span as the construction progresses.
are installed at the tip of the tension member, and are interlocked with each other according to the design values for each construction state in order to ensure a predetermined cable eccentricity and tension. For construction management, a central control panel (not shown) centrally controls the stroke of the cable eccentric jack 1 and the hydraulic pressure of the tension adjustment jack 3.

FIGS. 2 and 3 show the installed state of the cable eccentric jack 1 in more detail. The cable eccentric jacks l are installed on the left and right sides of the structure 2, and are fixed so that the rod 5 of the cable eccentric jack 1 can move up and down along the web 4 of the structure 2, and is tensioned at the lower end of the rod 5. Out cable 6 is attached as a material.

And the left cable eccentric jack l in Figure 2.
shows the state in which the rod 5 is moved upward, the cable eccentricity jack 1 on the right side shows the state at the time of repositioning, and the cable eccentricity jack 1 on the left side in Fig. 3 moves the rod 5 downward. The cable eccentric jack 1 on the right side is shown in the state when it is replaced.

Figures 4 and 5 show the arrangement of tendons during construction. In Fig. 4, a structure 2 with a hand-stretched begirder 7 attached to its tip is constructed across a fulcrum pt and a fulcrum 22, and above the fulcrum P, an out cable 6 operates an eccentric jack l upward. By operating the eccentric jack 1 downward at the center of the span between the fulcrums P1 and P2, the out cable 6 is placed at the lowest height position as shown in FIG. will be established. Further, on the fulcrum P2, the out cable 6 is arranged at an intermediate height position. And the accompanying out cable 6
For changes in length, the tension of the out cable 6 is adjusted by the tension adjustment jack 3.

In FIG. 5, the structure 2 is further extruded and the tip of the hand-stretched begirder 7 is placed on the fulcrum P3. On the fulcrum P2, the out cable 6 connects the eccentric jack 1 upward. When activated, it is placed at the highest height position as shown in FIG. Further, by operating the eccentric jack 1 downward at the center of the span between the fulcrum P2 and the fulcrum P3, the out cable 6 is disposed at the lowest height position.

As mentioned above, during extrusion construction, the eccentric jacks 1 installed at the required pitch move the center part of the span downwards in the cross section.
On the fulcrum, the out cable 6 is repeatedly moved upward and downward in the cross section, and the arrangement shape of the out cable 6 is changed according to the state of the acting moment at each construction stage. The arrangement state is as follows.

The entire out cable 6 disposed at a required position is covered with a cover 7. The cover 7 has a semicircular cross section as shown in FIG. 11, and is attached to the inner surface of the web 4 of the structure 2 with anchor bolts 8. Further, in the internal space between the cover 7 and the web 4, a dowel 9 is provided to protrude from the inner surface of the web 4, and grouting is further performed in the internal space. The out cable 6 is further fixed to the web 4 at the bent portion by a cable position fixing anchor 10.

(Effects of the Invention) This invention moves the tendons up and down in accordance with the fluctuations of the girder self-weight moment at each cross section during construction, thereby reducing the need for tendons during construction, which was conventionally required only during construction. It is possible to significantly reduce the quantity and also eliminate work such as releasing tension after completion. In addition, it is possible to eliminate the work of inserting the completed cable after the completion of construction and releasing the tension of the steel rod during construction.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view showing the installation state of the device of the present invention, Fig. 2 is a cross-sectional view showing the state in which the rod of the eccentric jack is moved upward and the state when the jack is replaced; The figure is a cross-sectional view showing the state in which the rod of the eccentric jack is moved downward and the state in which the jack is replaced. Figures 4 and 5 are schematic side views showing the arrangement of the out cable during construction. Figure 6 is a schematic side view showing the arrangement of out cables in the completed system, Figure 7 is a sectional view taken along A-A, and Figure 8 is shown along B-B.
9 is a schematic side view showing the fixed state of the out cable of the completed system, FIG. 10 is a C-C sectional view, and FIG. 11 is a sectional view showing the state of attachment of the out cable in the structure part. It is. 1... Cable eccentric jack, 2... Structure, 3
...Tension adjustment jack, 4...Web, 5...
Rod, 6...Out cable, 7...Hand-stretched begada, 8...Anchor bolt, 9...Dowel, 10.
...Cable position fixing anchor 11...PC steel rod. 34-

Claims (2)

[Claims] (1) In a structure construction method in which the stress acting on the same cross section of a member fluctuates or reverses its polarity due to changes in construction conditions, some or all of the tension members are placed with out-cables, and the position of the out-cables is A structure characterized in that the structure is actively moved vertically at any time by an eccentric position moving device, and at the same time a predetermined tension is maintained by a tension adjustment device in response to the accompanying length fluctuations of the tendon material. Construction method. (2) The eccentric moving device consists of a cable eccentric jack, which is installed on the top surface of the structure,
The apparatus for constructing a structure is characterized in that the tension adjustment device includes a tension adjustment jack, and the tension adjustment jack is installed at an end of the tendon material.