The present invention relates to a method for constructing precast coping for bridge. More particularly, the present invention relates to a method for constructing precast coping for bridge to use a main segment match-cast manufactured with the top of a pier body, to introduce a subsegment match-cast manufactured with both sides of the main segment to transverse tendon force through tendons, and to install lifting lugs on the top of the main segment or the subsegment.
Coping is formed on the top of a body in order to have a width corresponding to a transverse width of a bridge for supporting a girder in the top of a pier. Previously, after assembling and installing mould on the top of the bridge and pouring concrete while gradually constructing the bridge from the bottom of the bridge in place, concrete is cured and the coping is built on the top of the pier by disassembling the mould.
Meanwhile, the construction of bridges due to cast-in-place concrete has been less used for the reasons of the long period of construction, environmental problems, and civil complaints caused by environmental problems. Instead, the method for quick assembling and constructing pre-formed segments in a construction site has been widely used.
The fast construction method has been appearing as an alternative in that not only can the whole period of bridge construction be reduced, but environmental problems and civil complaints can be minimized. Also, it is true that the fast construction method helps construction environment mechanized by using large equipment.
There are advantages in which since a unit structure manufactured as a precast type, i.e., a segment, is manufactured in a uniform place and the quality of concrete is easily maintained, it is easy to maintain high-quality members; since segments are continuously manufactured, it is easy to control manpower and be used for mould only; and since segments may be manufactured with base construction, air may be cut as compared with the cast-in-place method.
If the assembling method is used, the bridge is constructed by gradually lifting up and assembling the pier body and the coping, manufactured with a plurality of segments, with cranes after building base concrete in which base sites are dug from the surface of the ground in place.
As above, in case that bridges are constructed by the assembling method, the body and the coping, composed of each unit structure, are lifted up by cranes and therefore, it may be much safer as self weight is getting reduced.
Therefore, the method for reducing the weight of the segment has been mainly studied. However, even though the weight of the segment is decreased, bearing capacity or seismic performance of the assembled bridges should not be diminished.
Especially, as for bridges, since a post and a coping are mainly affected by compressive load and bending load, respectively, the size of the side of the coping is generally large. Also, since the coping is usually more than a minimum of 10 meters long, the total weight of the coping is commonly quite heavy.
Therefore, the way to sharply reduce the self weight of the coping should be found out in order to seek the assembly bridge constructing method. As for girders, the size of the load for the coping is approximately 500 tons, five times of the size of the load for each girder, whereas the size of the load for each girder is generously approximately 100 tons. Therefore, the size of the side of the coping should be extremely bigger than that of the girder.
For this reason, the weight of the coping must be extremely large and therefore, the way to reduce self weight has been studied for fragmenting the coping.
To solve the above problem, a lightened coping for bridge was invented.
As illustrated in
However, it is difficult for the lightened coping for bridge to be moved after manufacture because the width of the coping of the lightened coping for bridge is the same as that of the bridge. Also, it is impossible to be applied except small-sized bridges due to its weight.
To solve the above problems, the object of the method for constructing precast coping for bridge of the present invention is to manufacture a segment match-cast manufactured with the top of a pier body; to be applied to small and medium size bridges by introducing transverse tendon force to each segment through tendons after manufacturing a subsegment which is match cast to both sides of the pre-made segment; to be rapidly produced; and to retension tendons when the coping is constructed by using a plurality of segments.
Further, the other object of the method for constructing precast coping for bridge of the present invention is to manufacture the method for constructing precast coping for bridge, enabling to obtain stability towards lift by easily lifting the coping, assembled on the ground, through lifting lugs by forming lifting lugs on the top upon manufacturing segments.
Additionally, the other objects of the method for constructing precast coping for bridge of the present invention are to manufacture a main segment with the upper side of the segment, corresponding to the top pier body, as molding upon manufacturing neighboring segments; to easily combine each segment in the construction by manufacturing a new segment with the side of the main segment as molding or match-cast manufacturing other new segments with the side of new segments as molding; and to previously protect water leakage through discontinuity of each segment upon displaying tendons to neighboring segments continuously by deleting discontinuity of each neighboring segment.
Further, the other objects of the method for constructing precast coping for bridge of the present invention are to connect each segment solidly by interconnecting segments through a shear key upon assembling each neighboring segment and to support the weight on the surface effectively.
Furthermore, the other object of the method for constructing precast coping for bridge of the present invention is to be easily delivered by a segment unit after construction due to segment unit manufacture in factories.
To accomplish the above object, the present invention is directed to a method for constructing precast coping for bridge, characterized in comprising: main segment manufacturing process for manufacturing a main segment to stack match-cast bottom of the main segment to the upper side of the top segment by using the surface of the top segment from pier body segments and molding and to form a first transverse sheath pier penetrating transverse tendons; subsegment manufacturing process for manufacturing a subsegment to build a second transverse sheath pier corresponding to the first transverse sheath pier of the main segment penetrating the transverse tendons when the subsegment is match-cast manufactured by using the both sides of the main segment as molding; transverse tendon force introducing process for introducing transverse tendon force through the transverse tendons which are inserted to the first transverse sheath pier and the second transverse sheath pier after combining the subsegment to the both sides of the main segment; and the longitudinal tendon force introducing process for introducing longitudinal tendon force through longitudinal tendons inserted to the longitudinal sheath pier after lifting the main segment in which the subsegment is combined to both sides and stacking the main segment to the upside of the pier body segment.
Here, the method for constructing precast coping for bridge further comprises additional segment manufacturing process for manufacturing the additional segment to form a third transverse sheath pier corresponding to the first transverse sheath pier and the second transverse sheath pier penetrating the transverse tendons through match casting in which the both sides of the segment is used as molding.
Also, the main segment includes a socket corresponding to a shear connector of the body segment, a longitudinal sheath pier, a vertical steel bar, and a horizontal steel bar.
Here, a plurality of lifting lugs are inserted to the upside of the main segment, and a plurality of protruded shear keys are installed to the both sides of the main segment.
Additionally, the lifting lug consists of: a plurality of anchors for forming a tap to combine nuts on the top, forming a curve on the bottom, welding and fixing the horizontal steel bar of the main segment to the top and the bottom, and protrudedly forming the top toward the top of the main segment when the anchors are shaped like a circle stick; a base for forming a first anchor hole, into which the anchor is penetrated, and being horizontally laid on the top of the main segment when the base is shaped like a metal rectangular plate; a slab for forming a second anchor hole, into which the anchor is penetrated, and being fixed to any one of upper sides of the main segment, subsegment, and additional segment, which are the positions corresponding to the base, by the nut of the anchor when the slab is shaped like a metal rectangular plate as the same as the base; and transverse tendons for being longitudinally welded and combined in the center of the upper side of the slab.
Here, transverse tendons consist of: a main body for protrudedly forming a center with a curve, forming a lifting hole, and being vertically welded and connected to the upper side of the slab when the main body is shaped like a metal rectangular plate; a reinforcing raised spot which is all formed around the lifting hole of the main body; and a support panel for welding one side in order to be vertically crossed with the main body, vertically welding and combining the bottom to the upper side of the slab, and supporting both ends of the main body.
Here, if road transport load of the main segment is exceeded, two divided sides are match-cast manufactured each other, a plurality of protruded shear connectors are installed to the bottom of divided sides, and the socket is installed to combine the shear connector to the upper side of divided sides when the main segment is horizontally divided.
In addition, the subsegment includes a shear key groove combined to the shear key of the main segment in one side, and a plurality of protruded subshear keys in the other sides.
Moreover, the additional segment includes a subshear key groove combined to the subshear key of the subsegment in one side.
Also, epoxy is applied and adhered between the main segment and the subsegment or the subsegment and the additional segment.
Further, the connection part of the main segment and the subsegment or the subsegment and the additional segment is not piled up with bridge support or critical sections.
Furthermore, the main segment and the additional segment, or the main segment, the subsegment and the additional segment determine partition number of each segment depending upon road transport load.
According to the method for constructing precast coping for bridge of the present invention, constituted as above, it enables to be applied to small and medium size bridges by introducing each neighboring segment to transverse tendon force through tendons when coping is constructed by using a plurality of segments; to relatively reduce manufacturing period and costs due to rapid construction; and be easily maintained by retensioning tendons when the coping is constructed by using a plurality of segments.
More, according to the present invention, it enables to easily lift coping upon lifting and to obtain stability towards lifting by forming lifting lugs on the ground upon manufacturing segments and combining lifting lugs and lifting devices, which are formed in the coping assembled on the ground, through ropes or wires.
Moreover, according to the present invention, it enables to easily combine each segment upon match-cast manufacturing an additional segment with the side of the pre-made segment as molding when manufacturing neighboring segment, and to previously protect water leakage through discontinuity of each segment upon displaying tendons to neighboring segments continuously by deleting discontinuity of each neighboring segment.
In addition, according to the present invention, it enables to connect each segment solidly by interconnecting segments through a shear key upon assembling each neighboring segment and to support the weight on the surface effectively.
Moreover, according to the present invention, it enables to be easily delivered by segment unit after construction due to segment unit manufacturing in factories.
Hereinafter, an explanation of the method for constructing precast coping for bridge according to the present invention will be given with reference to the attached drawings.
A detailed explanation on the known functions and configurations related to this invention will be avoided for the brevity of the description. And, the terms as will be mentioned below are used by the functions defined in this invention, which is of course varied in accordance with the intension or rules of a user or operator. Therefore, the definition of the terms should be based upon the contents of the description of the invention.
Referring to
First, when the main segment (110) is formed like a bigger cuboid than the diameter of the top segment (101) among pier body segments, the bottom of the main segment (110) is match-cast by using the upper side of the top segment (101) and molding; the main segment (110) includes a socket (111) corresponding to a shear connector (101a) of the body segment (101), a longitudinal sheath pier (113), and vertical and horizontal steel bars (115); and the main segment (110) forms a first transverse sheath pier (117) to penetrate transverse tendons (140). Here, the main segment (110) is connected to each other upon assembling a subsegment (120), explained as below, and includes a plurality of protruded shear keys (119) on both ends to effectively support top load.
Meanwhile, when road transport load of one segment of the main segment (110) is exceeded according to traffic law, two divided sides are match-cast manufactured each other, a plurality of protruded shear connectors (111a) are installed to the bottom of divided sides, and the socket (111) is installed to combine a shear connector (110a) to the upper side of divided sides when the main segment (110) is horizontally divided as shown in
Also, when the subsegment (120) includes vertical and horizontal steel bars (121) inside the subsegment (120) and is shaped like a smaller cuboid than the main segment (110) in terms of length and height, the bottom of the subsegment (120) is on a slant to reduce self weight and focus on weight toward the main segment (110), and a second transverse sheath pier (123) corresponding to a first transverse sheath pier (117) of the main segment (110) is formed to penetrate transverse tendons (140). Here, the subsegment (120) is manufactured by match-cast using both ends of the main segment (110) as molding, and a shear key groove (125) combined to the shear key (119) of the main segment (110) is formed to the one side.
In addition, an additional segment (130) may be further installed by the outer of each subsegment (120) in the present invention.
At this point, a plurality of protruded subshear keys (127) are installed to the other side of the additional segment (120).
Further, when the additional segment (130) includes vertical and horizontal steel bars (131) inside the additional segment (130) and is shaped like a smaller cuboid than the subsegment (120) in terms of length and height, the bottom of the additional segment (130) is on a slant to reduce self weight and focus on weight toward the main segment (110), and a third transverse sheath pier (133) corresponding to a first transverse sheath pier (117), which is placed on the top of the first sheath pier (117) of the main segment (110), is formed to penetrate transverse tendons (140). Here, the additional segment (130) is manufactured by match-cast using one side of the subsegment (120) as molding, and a subshear key groove (135) combined to the subshear key (127) of the additional segment (120) is formed to the one side.
Meanwhile, as illustrated in
At this point, as illustrated on
Here, transverse tendons (157) consist of: a main body (157-1) for protrudedly forming a center with a curve, forming a lifting hole (157-11), and being vertically welded and connected to the upper side of the slab (155) when the main body (157-1) is shaped like a metal rectangular plate; a reinforcing raised spot (157-3) which is all formed around the lifting hole (157-11) of the main body (157-1); and a support panel (157-5) for welding one side in order to be vertically crossed with the main body (157-1), vertically welding and combining the bottom to the upper side of the slab (155), and supporting both ends of the main body (157-1).
Meanwhile, it is desirable to apply and adhere epoxy (160) between the main segment (110) and the subsegment (120) or the subsegment (120) and the additional segment (130), and the connection part of the main segment (110) and the subsegment (120) or the subsegment (120) and the additional segment (130) is not piled up with bridge support (that is called, shoe, not illustrated).
Furthermore, the main segment (110) and the additional segment (120), or the main segment (110), the subsegment (120) and the additional segment (130) determine partition number of each segment depending upon road transport load.
Hereinafter, the method for constructing precast coping for bridge of the present invention is specifically explained referring to attached drawings as below.
First, each lifting lug (150) is formed in the center of the surface of the main segment (110) in accordance with design.
Next, as illustrated in
In this condition, as illustrated in
Meanwhile, the additional segment (130) may be further combined to the subsegment (120) of the present invention.
That is, the additional segment (130) is installed to each of both sides of the subsegment (120). At this point, the side of the subsegment (120) is covered with the epoxy (160); the subshear key (127) is formed to the side of the subsegment (120); match-cast sides are installed to be interconnected upon manufacturing the additional segment (130); and the subshear key (127) of the subsegment (120) and the subshear key groove (135) of the additional segment (130) is installed to be faced each other.
Next, transverse tendons (140) are penetrated into a first transverse sheath pier (117) of the main segment (110), a second transverse sheath pier (123) of the subsegment (120) and a third transverse sheath pier (133) of the additional segment (130) and then, transverse tendon force is applied at once by tensioning the transverse tendons (140).
Then, after constructing a bridge base (103) on the surface, the pre-made bridge segment is piled up on the upper side of the bridge pier (103) to the designed height in sequence.
Next, as illustrated in
In this condition, as illustrated in
Meanwhile, even though the process for lifting and combining the coping after assembling the coping on the ground is described, the main segment (110) and the subsegment (120) or the main segment (110), the subsegment (120) and the additional segment (130) may be lifted and installed in sequence while the body segment (101) is installed. At this point, after first performing longitudinal tension between the main segment (110) and the body segment (101), transverse tension is performed.
The present invention can be variously modified and embodied by several types of forms, and particular illustrative embodiments are merely described in the detailed description of the invention. However, it should be appreciated in such a manner that the present invention is not limited as a particular type, mentioned in the detailed description, but rather it comprises all modified materials, equal materials, and substitutes within the spirit and the range of the present invention, defined by the enclosed claims herewith.
Number | Date | Country | Kind |
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10-2009-0101831 | Oct 2009 | KR | national |
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