JPH0571747B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an improvement in the construction method of high-rise reinforced concrete structures.

[Problems to be Solved by the Invention] Various prefabricated construction methods have been developed to save labor and improve quality when constructing reinforced concrete structures. The PC beam construction method, in which the beams are highly prefabricated, is suitable for achieving the above objectives, but the biggest problem is the connection between the PC beams.
For example, when connecting PC beams at the center, leave about 500 mm of concrete on the PC beam, weld the reinforcing bars together, then construct the beam's starp bars, assemble the formwork around it, and pour the concrete. However, with a spacing of about 500 mm, the welding work space is narrow, and the length is not sufficient to bend the reinforcing bars to absorb errors in the position of the reinforcing bars embedded in the PC beam. 0.5~1.0mm
Although the length may be reduced to a certain extent, there are problems such as undesirable residual stress occurring at a length of about 250 mm.

Also, if two perpendicular directions are made of PC beams, it will be difficult to accommodate the intersection of the column and beam. That is, after setting the beams in one direction, the beams in the other direction are set, but if the reinforcing bars are arranged in two stages, upper and lower, it is difficult to intersect the reinforcing bars. Therefore, a one-way PC beam plan can be considered, which has a lower prefabrication rate than the two-way PC beam plan. In that case, the beams in one direction would be converted to PC, and the reinforcing bars in the other direction would be erected on-site, but erecting reinforcing bars on-site would not shorten the construction period.

As mentioned above, it is difficult to connect reinforcing bars embedded in PC beams. Also, it is difficult to assemble reinforcing bars on site. Therefore, in this invention, the reinforcing bars of the beams perpendicular to the PC beams are lifted and assembled as prefabricated bars that are pre-assembled to the PC beam bars in the ground assembly yard.

[Means for Solving the Problems] The configuration that is the gist of the present invention is that one beam is a precast reinforced concrete member, that is, a PC beam, and the reinforcing bars of the other beam orthogonal to the one beam are preassembled to form one beam. This unit member is assembled perpendicularly to the beam of the
While supporting the PC beam with shoring, the reinforcing bars of the other previously assembled beam are connected at the mid-span and placed inside the beam formwork, and cast-in-place concrete is poured inside the beam formwork. The reinforced concrete beam is integrally constructed by configuring the beams.

[Example] Unit member A constituting a beam manufactured in advance at a construction yard is a continuous combination of beams in two directions,
One of the beams 1 is a precast reinforced concrete member (PC member), with reinforcing bars protruding from the ends.
Further, the reinforcing bars of the other beam 2 perpendicular to the one beam 1 are assembled in advance so as to be perpendicular to the beam 1. This unit member A is T-shaped and I-shaped as shown in FIG.
It is formed in a shape such as a square shape or a square shape. In other words, one beam 1
The PC member part will have one or two spans, and the reinforcing bars of the other beam 2 will be connected at the middle of the span.

Note that the PC beam 1 has a structure in which the top reinforcing bars and the tops of the hoop bars are exposed.

During construction, the existing building frame B will be used and scaffolding C for replacement will be installed on the outside. Next, the prefabricated reinforcing bars 3 for columns are hung onto the existing frame B, and the column formwork 4 is erected. (See Figures 3 and 4) Next, the beam formwork 5 for replacement is lifted up and replaced using the internal space and installed on the existing frame. (See Figure 5) First, the PC beam 1
The beam formwork 5 perpendicular to the beam formwork 5 is lowered and set, and the floor formwork 6 or thin PC board is installed using supports 7 if necessary. Next, column concrete is placed using the floor formwork 6 as a working floor. (See Figure 6) Next, the unit member A that will become the component of the beam is suspended, and the PC member 1 is supported at a regular height by the shoring 8. (See Figure 7) Also, the beam reinforcing bars 2
position. (See Fig. 10) The reinforcing bars of the other beam 2 are connected, and then the beam formwork 5 is raised to its normal position (see Fig. 8).Then, cast-in-place concrete for the beam and floor is poured. (See Figure 9) The above steps are repeated in order to build the building to the required height.

[Effects of the Invention] This invention has the above-mentioned configuration, and when implementing a beam formwork replacement method during the construction of a reinforced concrete structure, one of the beams is made into a PC beam, and the other beam reinforcing bar perpendicular to this is made of pre-assembled reinforcing bars. By doing so,
There is no need to assemble the reinforcing bars orthogonally at the column location on-site, and most of the reinforcing bars are assembled in the factory, which reduces work at heights, makes construction safer, shortens the construction period, and makes it easier to connect reinforcing bars during construction. We have succeeded in improving the workability of each in a well-balanced manner.

[Brief explanation of the drawing]

Figures 1a, b, c, and d are plan views of the unit members constituting the beam, Figure 2 is a plan view of the arrangement of the unit members, Figures 3, 4, 5, 6, Figure 7,
FIGS. 8 and 9 are elevational views showing an outline of the construction process, and FIG. 10 is a plan view showing the reinforcing bars for columns and beams. A... Unit member, B... Existing frame, C... Scaffolding, 1... PC beam, 2... Beam reinforcing bar, 3... Prefabricated reinforcing bar for column, 4... Column formwork, 5... Beam formwork ,6...
...floor formwork, 7...support, 8...shoring, 9...
...Column, 10...Column main reinforcement.

Claims (1)

[Claims] 1 One beam is a precast reinforced concrete member, the reinforcing bars of the other beam that are orthogonal to one beam are pre-assembled, and the unit members assembled in a state perpendicular to the one beam are erected between the columns, and the one beam is In addition to supporting it with shoring, the reinforcing bars of the other previously assembled beam are joined at the mid-span and placed within the beam formwork, and cast-in-place concrete is poured into the beam formwork to support the other beam. A construction method for reinforced concrete structures characterized by: