Prefabricated prestressed high-performance concrete composite beam based on dry connection and construction method
Technical Field
The invention belongs to the technical field of buildings, and particularly relates to a prefabricated prestressed high-performance concrete composite beam based on dry connection and a construction method.
Background
In the research process of the prestressed steel-concrete composite beam, it is difficult to ensure that all the prestress is accurately applied to the concrete of the lower flange, and the section steel and the concrete of the upper flange always bear part of the prestress. The concrete and the section steel are simply separated, and the lower flange of the concrete on one side is prestressed, so that the concrete on the compression flange bears a part of prestress, and before the prestressed concrete is not assembled, cracks are generated on the tension side due to large bias, and even the whole component is unstably damaged. There is a need for a simple and effective prestressed concrete composite girder to solve the problem that it is difficult to completely precisely apply prestress to concrete on the side in tension. In addition, the traditional steel-concrete composite beam construction process is complex, wet operation cannot be avoided in many processes, the construction period is long, the assembly type dry connection can greatly shorten the construction period, and the cost is saved.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a prefabricated prestressed high-performance concrete composite beam based on dry connection and a construction method thereof.
In order to achieve the above purpose, the invention adopts the technical embodiments that:
a precast prestressed high-performance concrete composite girder based on dry type connection, comprising:
the web plate of the I-shaped steel is provided with a plurality of through round holes along the length direction;
the split concrete strips are arranged on two sides of the web plate of the I-shaped steel, are positioned between the upper flange and the lower flange, and are provided with through holes coaxial with the round holes, wherein the through holes on at least one side are gradually-widened holes, and the gradually-widened holes are formed by linearly increasing the aperture of the gradually-widened holes along the direction from the web plate to the outside;
the precast concrete connecting piece is consistent with the shape of the gradually widening hole, is at least filled in the gradually widening hole on one side, and is provided with a reserved hole which is coaxial with the gradually widening hole;
the bolt connecting piece penetrates through the reserved hole and the round hole and connects the I-shaped steel, the split concrete strip and the precast concrete connecting piece into a whole;
the prestressed tendons are arranged in the split concrete strips and are consistent with the length direction of the I-shaped steel.
Preferably, the split concrete strips are composed of two non-prestressed split concrete strips and two prestressed split concrete strips, the prestressed tendons are arranged in the prestressed split concrete strips, one non-prestressed split concrete strip and one prestressed split concrete strip are respectively arranged on two sides of a web plate of the i-steel, the non-prestressed split concrete strips are located above the prestressed split concrete strips, the tops of the non-prestressed split concrete strips are in contact with the upper flange, the bottoms of the prestressed split concrete strips are in contact with the lower flange, and grooves are formed in the bottoms of the non-prestressed split concrete strips and the tops of the prestressed split concrete strips so as to correspondingly form the via holes.
Preferably, the sections, perpendicular to the length direction, of the non-prestressed split concrete strips and the prestressed split concrete strips are rectangular, the grooves are wedge-shaped and increase from inside to outside, the appearance of the precast concrete connecting piece is a hexagonal frustum pyramid, the slope of each side of the frustum pyramid is matched with the grooves, and the height of the frustum pyramid is smaller than the depth of the grooves.
Preferably, when the I-steel, the split concrete strips and the precast concrete connecting piece are connected into a whole, a compaction space is reserved between the precast concrete connecting piece and the web plate of the I-steel in the gradually-widened hole.
Preferably, its characterized in that, the via hole of I-steel web both sides is gradually wide hole, and the gradually wide hole of both sides all is filled with precast concrete connecting piece, bolt connecting piece is for split bolt, passes the reservation entrance to a cave of reservation, round hole and the reservation entrance to a cave of opposite side of one side in proper order, will I-steel, components of a whole that can function independently concrete strip and precast concrete connecting piece connect as an organic wholely.
Preferably, when the split concrete strips are composed of two non-prestressed split concrete strips and two prestressed split concrete strips, the non-prestressed split concrete strips are located above the prestressed split concrete strips, and a gap enough to conveniently tighten the nut is reserved between the non-prestressed split concrete strips and the prestressed split concrete strips on each side.
Preferably, its characterized in that, the via hole of I-steel web one side is for gradually widening the hole, or the via hole of web both sides is gradually widening the hole but only has the gradually widening hole of one side in the packing precast concrete connecting piece, bolted connection is nested formula high strength bolt, including one-way bolt and conical head nut, the conical head nut penetrates the round hole, and one-way bolt passes and reserves the entrance to a cave and is connected with the conical head nut.
Preferably, the one-way bolt only has a thread at the front end, a sleeve is arranged in the round hole, the inner wall of the sleeve is conical, the conical head nut is matched with the sleeve for use, and the sleeve is provided with a notch which can be expanded under the action of the conical head nut, so that the effect of tight connection with the I-shaped steel web plate is achieved.
The invention also provides a construction method of the precast prestressed high-performance concrete composite beam based on dry connection, which comprises the following steps:
step 1), cutting a steel plate into circular holes in a factory, and welding the circular holes into I-shaped steel;
step 2), prefabricating split concrete strips by using a mould in a factory;
and 3) in a factory, putting and erecting the I-beams on the side, positioning the prefabricated split concrete strips to enable gradually-widened holes to be filled with the prefabricated concrete connecting pieces to be located on the upper sides, then putting the prefabricated concrete connecting pieces into the gradually-widened holes, finally penetrating the bolt connecting pieces, overturning the I-beams to install the other side member, and overturning the I-beams for 90 degrees to stack after the completion.
Preferably, the split concrete strips consist of two non-prestressed split concrete strips and two prestressed split concrete strips, in the step 2), the two prefabricated split concrete strips adopt a unified mould, wherein the non-prestressed split concrete strips are directly cast with high-strength steel fiber concrete, and then steam curing is carried out in a curing chamber to a certain strength and demoulding is carried out; the prestressed split concrete strip is firstly tensioned with prestressed reinforcements to achieve the controlled stress before concrete pouring, then the die and the anchorage device are sent into a curing chamber together for steam curing, and the prestressed reinforcements are cut off when the concrete strength reaches over 75 percent of the designed value.
Compared with the prior art, the invention has the beneficial effects that:
1. accurate control of prestressing
The method has the advantages that the concrete on the tension side and the concrete on the compression side are separated, the I-shaped steel is separated from the I-shaped steel to independently apply the prestress, the size of the prestress applied to the concrete can be accurately mastered, the condition that the prestress part is borne by the I-shaped steel and the compression flange of the concrete in the traditional application process is changed, the I-shaped steel and the compression flange of the concrete are separated into the concrete strips with small sections, the prestressed tendons are arranged at the centroids of the sections of the concrete strips, and the possibility that the concrete strips are unstable after being demoulded in a prefabrication stage is avoided.
2. Saving material
In the invention, under the constraint of concrete, the out-of-plane stability of the steel structure plate on the pressed side is greatly improved, thereby improving the utilization rate of materials and saving steel; the web of the I-shaped steel adopts a honeycomb web, the upper flange and the lower flange are expanded under the condition of limited materials, the bending resistance bearing capacity of the section is improved, and the honeycomb web is used as a channel for cast-in-place concrete, so that the overall performance of the structure is enhanced. In addition, the anchor bolt connecting piece on the concrete web in the traditional structure is omitted, and the prefabricated concrete connecting piece is used for resisting longitudinal shearing force, so that steel is greatly saved.
3. Increased strength
The invention expands the section, gives full play to the prestress and greatly improves the bending resistance bearing capacity of the section.
4. The construction speed is high
The invention has high prefabrication rate, completely adopts dry connection, completes all construction processes in a factory, can well maintain products, has higher precision of the die, can synchronously produce and then assemble products, and improves the production speed of the products while ensuring the quality of the products.
Drawings
Fig. 1 is a schematic structural view of the present invention.
FIG. 2 is a schematic structural view of an I-beam of the present invention.
Fig. 3 is a schematic view of a precast concrete connection member according to the present invention.
Figure 4 is a schematic view of a non-prestressed concrete split strip according to the present invention.
Figure 5 is a schematic view of a prestressed concrete split strip according to the present invention.
Fig. 6 is a schematic structural diagram of the first embodiment of the present invention.
FIG. 7 is a schematic view of the nested high strength bolt of the present invention.
FIG. 8 is a schematic diagram of a connection structure according to an embodiment of the present invention.
FIG. 9 is a schematic structural diagram of a second embodiment of the present invention.
Fig. 10 is a schematic configuration diagram of a third embodiment of the present invention.
Detailed Description
The embodiments of the present invention will be described in detail below with reference to the drawings and examples.
As shown in fig. 1, the present invention is a precast prestressed high-performance concrete composite girder based on dry type connection, including:
the web of the i-steel 3 is provided with a plurality of through holes 10 along the length direction, and as shown in fig. 2, the holes 10 can be arranged in one row or in a plurality of rows from the upper flange to the lower flange.
And the split concrete strips are arranged on two sides of the web plate of the I-shaped steel 3, are positioned between the upper flange and the lower flange, and are provided with through holes which are coaxial with the round holes 10. Wherein, the via hole of at least one side is gradually wide hole, gradually wide hole means its aperture along the outside direction linear increase of web.
The precast concrete coupler 4, referring to fig. 3, is in conformity with the shape of the gradually widening hole and is filled in the gradually widening hole at least at one side, and a reserved hole 11 coaxial with the gradually widening hole is provided thereon. Illustratively, the inner part of the frame can be provided with a second longitudinal rib 16 which is parallel or slightly inclined along the axial direction, and a second stirrup 17 is arranged around the second longitudinal rib 16.
The bolt connecting piece penetrates through the reserved hole 11 and the round hole 10, and the I-shaped steel 3, the split concrete strip and the precast concrete connecting piece 4 are connected into a whole to play a role in resisting longitudinal shear.
And the prestressed tendons 5 are arranged in the split concrete strips and are consistent with the length direction of the I-shaped steel 3. For example, the prestressed reinforcement 5 may be constructed by a pretensioning method, and the material may be selected from prestressed steel wires, steel strands, and prestressed threaded steel bars.
For example, referring to fig. 1, 4 and 5, the split concrete strips are composed of two non-prestressed split concrete strips 1 and two prestressed split concrete strips 2, and both the non-prestressed split concrete strips 1 and the prestressed split concrete strips 2 may be provided with longitudinal ribs one 14 and hoop ribs one 15. The prestressed reinforcement 5 is arranged in the prestressed split concrete strips 2, the two sides of a web plate of the I-shaped steel 3 are respectively provided with a non-prestressed split concrete strip 1 and a prestressed split concrete strip 2, the non-prestressed split concrete strip 1 is positioned above the prestressed split concrete strips 2, the top of the non-prestressed split concrete strip 1 is in contact with the upper flange, the bottom of the prestressed split concrete strip 2 is in contact with the lower flange, and grooves 12 are formed in the bottom of the non-prestressed split concrete strip 1 and the top of the prestressed split concrete strip 2 so as to correspondingly form a via hole. Illustratively, the sections of the non-prestressed split concrete strips 1 and the prestressed split concrete strips 2 perpendicular to the length direction are rectangular, and the sections and the grooves 12 are the same in size. The groove 12 can be a wedge shape which is enlarged from inside to outside, the cross section of the through hole formed after buckling is a hexagon, therefore, the appearance of the precast concrete connecting piece 4 is a hexagonal frustum pyramid, the slope of each edge of the frustum pyramid is matched with the groove 12, and the height of the frustum pyramid is smaller than the depth of the groove 12. When the precast concrete connecting piece 4 is screwed up through the high-strength bolt, the expansion force generated when the split concrete strip can be screwed up is firmly locked on the surface of the I-shaped steel 3.
In the first embodiment of the present invention, referring to fig. 6, the through holes on one side of the web of the i-beam 3 are gradually widening holes, or the through holes on both sides of the web are gradually widening holes, but only one gradually widening hole is filled with the precast concrete connecting member 4. At this moment, in order to prevent the I-steel 3 and the concrete from sliding, the bolt connecting piece is a nested high-strength bolt, referring to fig. 7, the bolt connecting piece comprises a one-way bolt 6 and a conical head nut 7, the conical head nut 7 penetrates into a circular hole 10, and the one-way bolt 6 penetrates through a reserved hole 11 to be connected with the conical head nut 7. Illustratively, the one-way bolt 6 is threaded only at the front end and is provided with a washer 9 on the bolt body, a sleeve 8 is arranged in a round hole 10, and the round hole 10 is used as a passage for bolt connection and has a diameter matched with the outer diameter of the sleeve 8. The inner wall of the sleeve 8 is also conical, the conical head nut 7 is matched with the sleeve 8 for use, and the sleeve 8 is provided with a notch which can be expanded under the action of the conical head nut 7, so that the effect of tightly connecting with the web plate of the I-steel 3 is achieved. In addition, referring to fig. 8, when the i-beam 3, the split concrete strips, and the precast concrete connectors 4 are connected into a whole, a compaction space 13 may be left between the precast concrete connectors 4 and the web of the i-beam 3 in the gradually widened hole, so as to achieve a compaction effect.
In the second embodiment of the invention, referring to fig. 9, the through holes on both sides of the web of the i-steel 3 are gradually widened holes, the gradually widened holes on both sides are filled with precast concrete connectors 4, the bolt connectors are split bolts, and sequentially pass through the reserved hole 11 and the circular hole 10 on one side and the reserved hole 11 on the other side, so that the i-steel 3, the split concrete strips and the precast concrete connectors 4 are connected into a whole.
In the third embodiment of the present invention, referring to fig. 10, on the basis of the second embodiment, the split concrete strips are composed of two non-prestressed split concrete strips 1 and two prestressed split concrete strips 2, the non-prestressed split concrete strips 1 are located above the prestressed split concrete strips 2, and a gap enough to facilitate the nut tightening is reserved between the non-prestressed split concrete strips 1 and the prestressed split concrete strips 2 on each side.
Namely, the three embodiments are basically the same in principle, but different from the first embodiment, the bolts of the second embodiment do not adopt nested one-way bolts, but adopt split bolt connection, prefabricated concrete connectors are arranged on two sides of a web plate, and all members are symmetrically distributed around the web plate; example three-phase comparison example one, it is not the keyway of the concrete connection piece that is used as the passageway to tighten the nut that there is a large gap between the non-prestressed concrete split bar and the prestressed concrete split bar, and this gap is enough to facilitate the tightening of the nut.
The upper flanges of the non-prestressed split concrete strips 1 and the I-beams 3 are used for bearing the compressive stress of the stressed side of the section of the whole beam, and the lower flanges of the prestressed split concrete strips 2 and the I-beams 3 are used for bearing the tensile stress of the stressed side of the section of the whole beam. The prestressed tendons 5 can effectively improve the bending resistance of the cross section, so that the accurate application of all prestressing on the concrete on the tension side has a good effect.
In order to avoid the condition that the two split concrete strips are not broken due to self weight in the assembling and moving process, all the concrete members adopt the ultra-high performance steel fiber concrete.
The invention not only ensures that the prestress is accurately applied to the concrete, but also can limit the out-of-plane displacement of the I-beam 3 plate in the compression area and increase the out-of-plane stability of the I-beam 3, and the invention completely adopts dry connection, and the components are completely prefabricated, thereby greatly improving the production efficiency and shortening the construction period.
All components can be synchronously processed and manufactured, and finally, the components can be put into use after being assembled, so that complete assembly is realized. The construction steps are as follows:
step 1, cutting a steel plate into circular holes 10 in a factory, and welding the circular holes into I-shaped steel 3;
step 2, prefabricating split concrete strips by using a mould in a factory;
and 3, in a factory, placing and erecting the I-shaped steel 3 on the side, positioning the prefabricated split concrete strips to enable the gradually-widened hole to be filled with the prefabricated concrete connecting piece 4 to be located on the upper side, then placing the prefabricated concrete connecting piece 4 into the gradually-widened hole, finally penetrating a bolt connecting piece, overturning the I-shaped steel 3 to install a component on the other side, and overturning the I-shaped steel 3 for 90 degrees to stack after the completion.
More specifically, when the split concrete strips are composed of two non-prestressed split concrete strips 1 and two prestressed split concrete strips 2, the complete construction steps of the invention are as follows:
step 1), cutting and punching steel plates and welding the steel plates into I-shaped steel 3 in a factory;
step 2), in a factory, adopting a unified mould for the two prefabricated split concrete strips, wherein the non-prestressed split concrete strip 1 is directly poured with high-strength steel fiber concrete and then subjected to steam curing in a curing room to a certain strength, and then demoulding is carried out; the prestressed reinforcement is firstly tensioned to achieve the stress control before the concrete is poured into the prestressed split concrete strip 2, then the die and the anchorage device are sent into a curing chamber together for steam curing, and the prestressed reinforcement can be cut off when the strength of the concrete reaches over 75 percent of the design value.
And 3) in a factory, in order to facilitate the installation of bolts, putting and erecting the I-shaped steel 3 on the side, positioning the non-prestressed split concrete strips 1 and the prestressed split concrete strips 2 which are positioned on the upper side after being erected, then putting the precast concrete connecting pieces 4 into the grooves 12, and finally penetrating the bolt connecting pieces. Taking a nested high-strength bolt as an example, a one-way bolt 6 is inserted, a sleeve 8 is placed on the other side of a web plate, a cone head nut 7 is screwed, an I-shaped steel 3 is turned over, a concrete member on the other side is installed, and the concrete member is turned over for 90 degrees to be stacked after the completion.