Background
Under the new development situation, the nation actively promotes the transformation and upgrade of the construction industry, and the assembly type building is rapidly developed with good economic, environmental and social benefits. At present, in engineering practice, the most extensive prefabricated components are prefabricated laminated slabs. In the main design specifications of the prefabricated concrete structure in China, the bottom ribs in at least one direction of the prefabricated composite slab are required to extend into the laminated layers of the peripheral components, so that the connection performance and the integrity of the prefabricated composite slab and the structure are improved. However, a large number of steel bars are usually reserved on the peripheral components of the prefabricated composite slab, and bottom bars extending out of the side edges of the prefabricated composite slab interfere with the peripheral components in the installation and positioning process of the prefabricated composite slab, so that the installation difficulty of the prefabricated composite slab is greatly improved, the construction efficiency is reduced, even the prefabricated components are damaged, and the application advantages of the prefabricated composite slab are greatly offset. In fact, from the aspect of stress, the bottom rib part of the precast slab, which extends into the peripheral component from the bottom of the precast slab, is stressed less under normal conditions, and only plays a role in preventing the floor from falling under the action of earthquake load, so that the utilization efficiency is low.
With the progress of building material technology, Ultra-High Performance Concrete (UHPC) has been developed greatly, and has excellent properties such as Ultra-High strength, High toughness, High impermeability and High corrosion resistance, and is expected to become a basic material for the construction of next-generation infrastructure. However, due to the ultra-low water-to-gel ratio and the higher amount of gelled material, hot curing is often required to effectively reduce drying and creep shrinkage, and ensure the development of material strength. And UHPC viscosity is high, is difficult for the pump sending, and cast-in-place operation is relatively less. Because of the extremely high initial cost of UHPC, it is used less in building construction.
Due to the characteristics of the UHPC and the advantages of the fabricated concrete building structure, the combination of the UHPC and the fabricated concrete building structure can exert the advantages of the UHPC and the fabricated concrete building structure to the maximum extent, and avoid the related disadvantages. The demand that the prefabricated concrete laminated bottom plate reduces the extending ribs and improves the construction efficiency can be effectively solved in a UHPC local reinforcing mode, and the invention is provided for the demand.
Disclosure of Invention
In order to solve the problems, the invention discloses a local UHPC (ultra high performance concrete) enhanced efficient fabricated concrete composite slab, wherein a prefabricated UHPC block is used at the joint of the lower part of the prefabricated concrete composite slab, and the connection between a bottom plate of the prefabricated composite slab and a building structure is carried out through an angle steel connector, so that the problem that the bottom rib of the prefabricated composite slab stretches out to influence the installation efficiency is solved, and the connection strength and the energy consumption capability after the installation are simultaneously finished; the advantages of the ultrahigh-performance material and the prefabrication technology are combined, the material performance is exerted, and the influence of the manufacturing cost is reduced.
In order to achieve the purpose, the technical scheme of the invention is as follows:
a local UHPC reinforced efficient fabricated concrete laminated slab comprises a prefabricated UHPC reinforcing block, a prefabricated concrete bottom plate, an angle steel connecting piece, an upper common steel bar and cast-in-place concrete.
The prefabricated UHPC reinforcing block comprises a crossed bottom rib, a pre-buried bolt column and a prefabricated UHPC block. The prefabricated UHPC block wraps the crossed bottom ribs and the embedded bolt hole parts, and a square groove is reserved on the bottom surface; the crossed bottom ribs form a grid in a shape like a Chinese character 'jing', extend out of the left side edge, the right side edge and the front side edge of the prefabricated UHPC block, and the extension length is greater than the lap joint length of the steel bars; the embedded bolt columns are perpendicular to the crossed bottom ribs, embedded bolt holes are formed in the lower ends of the embedded bolt columns, and eyelet ends are located in grooves in the bottom surfaces of the prefabricated UHPC reinforcing blocks. The prefabricated UHPC reinforcing block is used for reinforcing the joint of the prefabricated concrete bottom plate, so that the joint is not easy to damage under a large load.
The edges of the precast concrete bottom plate are uniformly distributed with the precast UHPC reinforcing blocks, and other parts are precast common concrete and are embedded with common reinforcing steel bar meshes; the common reinforcing mesh does not extend out of the precast concrete, and the problem that the extending ribs of the conventional precast laminated slab interfere with peripheral members does not exist during subsequent hoisting.
Long slotted holes parallel to the length direction are reserved on one side of the angle steel connecting piece, and long slotted holes in the vertical direction are reserved on the other side of the angle steel connecting piece; the angle steel connecting piece passes through the long slotted hole in the vertical direction through a bolt and is arranged in a pre-buried bolt hole in the groove on the bottom surface of the UHPC reinforcing block; the angle steel connecting piece is embedded with a lead block at the inner side of the corner, and is used for improving the energy consumption capacity under the action of earthquake loads.
After the precast concrete bottom plate is installed in a building structure, the lower installed angle steel connecting piece is connected with a bolt hole pre-embedded in the building structure through a bolt penetrating through a long slotted hole in the direction parallel to the length direction, when an error exists in installation, the bolt on the other side can be loosened for adjustment, and after the adjustment is completed, all the bolts can be screwed to complete the installation.
And the upper common steel bars extend into the superposed layers of the peripheral members of the precast concrete bottom plate, the cast-in-place concrete is poured on the precast concrete bottom plate, and a complete floor slab is formed after curing and hardening.
Preferably, the thickness of the prefabricated UHPC reinforcing blocks is consistent with that of the prefabricated concrete bottom plate.
Preferably, the prefabricated UHPC reinforcing block can be provided with vertical anchoring ribs; and hooks are arranged at two ends of the vertical anchoring rib, one end of the vertical anchoring rib is bound with the crossed bottom rib, and the other end of the vertical anchoring rib is perpendicular to the crossed bottom rib and extends upwards out of the prefabricated UHPC block, so that the combination capacity of the prefabricated UHPC and common concrete is further improved.
Preferably, the surface of the angle steel connecting piece is plated with an anticorrosive coating, so that the durability is improved; according to the construction scheme on site, the precast concrete bottom plate can be installed after being hung in a building structure.
Preferably, the depth of the groove in the bottom surface of the prefabricated UHPC block is slightly larger than the sum of the thickness of the steel plate on one side of the angle steel connecting piece and the thickness of the end head of the bolt, so that a space is reserved for plugging subsequent common mortar.
Preferably, after the cast-in-place concrete is poured, the grooves in the bottom surface of the prefabricated UHPC block can be plugged by adopting common mortar, so that the angle steel connecting piece is further protected, and the attractiveness is improved.
A manufacturing and building method of a local UHPC reinforced high-efficiency fabricated concrete composite slab comprises the following steps:
(1) firstly manufacturing the prefabricated UHPC reinforcing block in a factory, and adopting high-temperature pressurized curing at 100 +/-5 ℃ and 2MPa to improve the manufacturing quality of the UHPC;
(2) arranging a side formwork on a conventional prefabricated laminated slab formwork according to the specification and the size of the prefabricated concrete bottom plate, fixing the UHPC reinforcing blocks close to the side formwork at a certain interval, then binding a common reinforcing mesh, performing lap-joint binding on the common reinforcing mesh and crossed bottom ribs of the UHPC reinforcing blocks, and performing maintenance after pouring common concrete;
(3) after the precast concrete bottom plate is hardened, the angle steel connecting piece is installed; after the precast concrete bottom plate is lifted to a preset position, a bolt penetrates through the long slotted hole of the angle steel connecting piece and is screwed into a bolt hole pre-embedded in a building structure for fixing; when the angle steel connecting piece cannot be tightly attached to peripheral components, the bolts on the precast concrete bottom plate can be loosened, the position of the angle steel connecting piece is adjusted forwards and backwards, and after the angle steel connecting piece reaches a proper position, all the bolts are screwed down;
(4) binding upper common steel bars, extending into the superposed layers of the peripheral members of the precast concrete bottom plate, and pouring common concrete to form a reliable whole.
(5) The installation part of the angle steel connecting piece is plugged by adopting common mortar.
The invention has the beneficial effects that:
(1) the invention cancels the side edge extending rib of the conventional precast concrete superposed bottom plate, avoids the interference of the extending rib in the installation process, improves the construction efficiency, reduces the labor cost and is beneficial to the popularization and the application of the fabricated concrete structure.
(2) The angle steel connecting piece provided with the mutually vertical long slotted holes is adopted, so that the mounting is flexible, the error is adjustable, the precision requirements of manufacturing and mounting of the prefabricated laminated slab are reduced, the production cost is further reduced, and the construction efficiency is improved; and the angle steel connecting piece is embedded with a lead block, so that the shock resistance and energy consumption capacity are improved.
(3) The invention realizes the high-temperature pressurized maintenance of the UHPC in a factory through the prefabrication technology, so that the UHPC obtains better material property, and simultaneously solves the problems of high viscosity, difficult pumping and large construction difficulty. The manufacturing cost is reduced, and the popularization and the application of the UHPC material are facilitated.
Detailed Description
The present invention will be further illustrated with reference to the accompanying drawings and specific embodiments, which are to be understood as merely illustrative of the invention and not as limiting the scope of the invention. It should be noted that the terms "front," "back," "left," "right," "upper" and "lower" used in the following description refer to directions in the drawings, and the terms "inner" and "outer" refer to directions toward and away from, respectively, the geometric center of a particular component.
As shown in fig. 1-2, firstly manufacturing the prefabricated UHPC reinforcing block in a factory, wherein the prefabricated UHPC reinforcing block is composed of cross bottom ribs 1, embedded bolt columns 2 and prefabricated UHPC blocks 3; vertical anchoring ribs 4 can also be additionally arranged, hooks are arranged at two ends of each vertical anchoring rib 4, and one end of each vertical anchoring rib is bound with the crossed bottom rib. The prefabricated UHPC block 3 partially wraps the crossed bottom ribs 1 and the embedded bolt holes 2, and square grooves 5 are reserved on the bottom surface. The crossed bottom ribs 1 form a grid in a shape of a Chinese character jing, extend out of the left side edge, the right side edge and the front side edge of the prefabricated UHPC block 3, and the extension length is greater than the lap joint length of the steel bars; on the embedded bolt post 2 vertical cross base muscle 1, the embedded bolt post 2 lower extreme is equipped with the embedded bolt hole, and the eyelet end is located prefabricated UHPC reinforcing block bottom surface recess 5.
As shown in fig. 3-4, according to the specification and size of the prefabricated concrete bottom plate, arranging a side formwork on a conventional prefabricated laminated slab bench formwork, fixing the prefabricated UHPC reinforcing blocks 6 close to the side formwork at a certain interval, then binding a common reinforcing mesh 7, wherein the common reinforcing mesh 7 does not extend out of the side formwork, overlapping and binding the common reinforcing mesh 7 and the extending parts of the crossed bottom ribs 1 of the prefabricated UHPC reinforcing blocks 6, and curing after pouring common concrete 8; after the precast concrete bottom plate is hardened, the angle steel connecting piece 9 is installed.
As shown in FIG. 5, a long slot 10 parallel to the length direction is reserved on one side of the angle steel connecting piece, a long slot 11 perpendicular to the length direction is reserved on the other side of the angle steel connecting piece, and a lead block 12 is embedded on the inner side of a folding angle.
As shown in fig. 6, after the precast concrete floor 13 is lifted to a predetermined position, bolts 14 pass through the long slotted holes 10 of the angle steel connecting pieces 9 and are screwed into bolt holes pre-embedded in the building structure 15 for fixing; when the angle steel connecting piece 9 can not be tightly attached to peripheral components, the bolts 16 on the precast concrete bottom plate can be loosened, the position of the angle steel connecting piece 9 is adjusted forwards and backwards, and after the angle steel connecting piece reaches a proper position, all the bolts are screwed down;
as shown in fig. 7-8, the upper common steel bars 17 are bound and extended into the overlapped layer of the prefabricated concrete bottom plate peripheral component 18, and the on-site common concrete 19 is poured to form a reliable whole. The installation part of the angle steel connecting piece is plugged by adopting common mortar.
The technical means disclosed in the invention scheme are not limited to the technical means disclosed in the above embodiments, but also include the technical scheme formed by any combination of the above technical features.