JP3471248B2 - Portal crane - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portal crane used to bridge a girder such as a PC girder between bridge piers at the time of bridging work or the like. 2. Description of the Related Art In a bridge construction work, a portal crane 30 as shown in FIG. 4 is conventionally used for lifting a girder material such as a PC girder and mounting it on a pier. The portal crane 30 is erected on a pier 31 and includes a chain block 33 for lifting a PC girder 32, a traversing truck 34 for moving the chain block 33 in the left-right direction, and columns 35 for supporting these. .
The column 35 is maintained in an upright state by a plurality of stay cable 40 connected to another pier (not shown) arranged adjacent to the pier 31. In this portal crane 30, a column 35
Is erected on a bracket 36 attached to both side edges of the pier 31 with its lower end abutting. The bracket 36 is locked by a steel bar 37 stretched on the pier 31 so as not to be detached from the pier 31. The reason why the interval between the columns 35 on both sides is set such that the lower end of the column 35 is located outside the both side edge portions of the pier 31 is that the outermost of the plurality of PC girders 32 laid on the pier 31 This is to prevent the upper flange of the PC girder 32a from interfering with the support pillar 35 when the PC girder 32a is erected on the side edge of the pier 31. [0004] P transported by a carriage 39 traveling on an erection girder 38 erected on a pier 31
The C girders 32, 32 a are lifted by the chain block 33 of the portal crane 30, moved laterally by the traversing carriage 34, and then placed at predetermined positions on the pier 31. By repeating such a process, a predetermined number of P
C digits 32, 32a can be arranged. [0005] The conventional portal crane 4
0 is a bracket 3 attached to both side edges of the pier 31.
Since the structure is such that the support 35 is erected through the intermediary 6, much work and time are required for installation and removal of the crane. In addition, when attaching and detaching the bracket 36, both side edge portions of the pier 31 may be damaged. In addition, since the bracket 36 receives the load applied to the lower end of the column 35, the bracket 36 and the side edges of the pier 31 are easily damaged, and in extreme cases, the bracket 36 may fall off. If the spacing between the posts 35 is reduced to avoid this, the upper flange of the PC girder 32a and the posts 35 interfere with each other when the outermost PC girder 32a is erected, so that the spacing between the posts 35 cannot be reduced. An object of the present invention is to provide a portal crane which can be easily installed and withdrawn, does not damage the pier, and can smoothly carry out the erection work of the girder material on both side edges of the pier. SUMMARY OF THE INVENTION The present invention relates to a portal crane which is installed on a pier at the time of bridge construction, and which is located at a lower edge portion of the crane support, at a side edge portion of the pier. And a supporting member for supporting the crane is formed. By forming such a support member, the crane load can be reduced by simply placing the lower end of the support on the top of the pier without using a bracket or other fastener that protrudes from the side edge of the pier. The crane can be erected on the pier in the form received by the section. This facilitates the installation and removal of the crane and does not damage the pier. Since the support member may be formed only at the lower end of the column, there is no interference between the upper flange of the PC girder and the support member when the outermost PC girder is erected. The support member can be attached by welding to the inside of the pier at the lower end of the crane support, or can be integrally manufactured from the beginning at the stage of manufacturing the support. In the method of mounting by welding, it is possible to modify the mounting of the support member at the lower end portion while keeping the existing crane support. If they are manufactured integrally from the beginning, the minimum additional material is sufficient, so that an increase in manufacturing costs can be suppressed. [0010] In this type of portal crane, the strut can be divided into two or three in the height direction in many cases. In the case of such a split type, the upper or middle part of the strut is left as it is, while the lower part is kept as it is. Only the support member may be formed by remodeling or separately manufacturing, so that an increase in remodeling or manufacturing cost can be suppressed. FIG. 1 is a front view showing a portal crane according to an embodiment of the present invention. FIG. 2 is an enlarged view of a portion A in FIG.
FIG. 3 is a cross-sectional view showing a mounting state of the support member. As shown in FIG. 1, a portal crane 10 of the present embodiment is erected on a pier 11 in bridge construction work.
It is used when installing a PC girder 12 between a plurality of piers 11. The portal crane 10 includes a chain block 13 for lifting a PC girder 12 and a chain block 1.
3 is provided with a traversing carriage 14 for moving the traverse 3 in a lateral direction and a support 20 for supporting the traversing carriage 14. The column 20 is kept upright by a plurality of stay cables 19 connected to a pier (not shown) installed adjacent to the pier 11 or the like. As shown in FIG. 2, the support 20 is an upper support 1.
A support member 16a, which is located at the side edge of the pier 11 and supports the load applied to the support post 20, is attached by welding to a pier inner portion at the lower end of the lower support 16 in a two-part type of the lower support 16 and the lower support 16. I have. An intermediate member 16x for preventing slip and dispersing pressure is interposed between the lower end of the support member 16a and the pier 11. A bogie 18 running on an erection girder 17 provided between the plurality of piers 11 is provided. The PC girders 12 and 12a conveyed by the gantry crane 10 are lifted by the chain block 13 of the portal crane 10, moved laterally by the trolley 14, and then placed at a predetermined position on the pier 11. Thereafter, the chain block 13 is connected to the erection girder 17.
After returning to the upper position, the PC girder 12 that has been transported next is lifted again, moved in the lateral direction by the traversing carriage 14, and then placed at a predetermined position on the pier 11. By repeating such a process a plurality of times, a predetermined number of PC girders 1
2 and 12a are erected. In the portal crane 10, the lower support 16
The support member 16a attached to the lower end of the pier 11
Since the lower end of the support member 16a is located on the upper surface of the intermediate member 16x installed on the side edge of the pier 11, the support 20 can be erected on the pier 11. Can be. Therefore, the installation and removal of the portal crane 10 is easy, and the pier 11 is not damaged.
Further, since the lower support 16 is located outside the both side edge portions of the pier 11, the work of erection of the PC girder 12a arranged on the both side edge portions of the pier 11 is not hindered, and the smooth work can be performed. it can. FIG. 3 is a cross-sectional view showing a mounting state of the support member 16a. FIG. 3A shows a state in which the support member 16a having a circular cross section is directly welded to the lower support 16 having a circular cross section.
(B) is a state in which a support member 16a having a square cross section is directly attached to a lower support 16 having a square cross section, and (c) is a support member 16a having a circular cross section is welded to the lower support 16 having a circular cross section via an auxiliary plate 16b. Attached state,
(D) shows a state in which a support member 16a having a rectangular cross section is attached to a lower support 16 having a rectangular cross section by welding via an auxiliary plate 16b. The symbol W in the drawing indicates a welded portion. Although the above embodiment is an example in which the support member is attached to the lower end of the lower support by welding, the lower support including the support member may be integrally manufactured from the beginning. The portal crane of the present invention can be obtained by assembling the lower support having the support member formed thereon in combination with the upper support of the split support. According to the present invention, the following effects can be obtained. (1) By forming a support member for supporting the crane at the side edge of the pier on the inner side of the pier at the lower end of the crane support, the lower end of the support can be simply placed on the upper surface of the pier. The crane can be erected on the pier while receiving the load of the crane at the side edge of the pier without using a locking tool such as a bracket projecting from the side edge of the pier. This facilitates the installation and removal of the crane and does not damage the pier. (2) By attaching the supporting member to the inner side of the bridge pier at the lower end of the crane support by welding, it is possible to modify the mounting of the support member at the lower end while keeping the existing crane support. Further, by integrally manufacturing the support columns from the beginning at the manufacturing stage, it is possible to suppress an increase in manufacturing cost with a minimum of additional materials.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view showing a portal crane according to an embodiment of the present invention. FIG. 2 is an enlarged view of a portion A in FIG. FIG. 3 is a cross-sectional view showing a mounting state of a support member. FIG. 4 is a front view showing a conventional portal crane. [Description of Signs] 10 portal crane 11 bridge piers 12, 12a PC girder 13 chain block 14 traversing carriage 15 upper support 16 lower support 16a support member 13b auxiliary plate 16x intermediate member 17 erection girder 18 carriage 19 stay cable 20 support

Claims (1)

(57) [Claims 1] In a portal crane installed on a pier at the time of bridge construction work, the cranes are located outside both side edges of the pier.
Combine with the upper column of the existing crane column
A pier inner portion of the lower end parts strut, taken by welding a support member for supporting the crane is positioned on the side edge of the pier
Attaching the lower support to the upper support of the existing crane support.
A portal crane in which a lower end of a support member attached to the lower support is mounted on an upper surface of an intermediate member for preventing slip and dispersing pressure installed on a side edge of the pier in combination with a column. .