CN105735469A - Partially-bonded precast prestressed concrete frame structure - Google Patents

Abstract

The invention relates to a partially-bonded precast prestressed concrete frame structure. The partially-bonded precast prestressed concrete frame structure is composed of prestressed tendons, precast concrete columns, precast concrete beams, precast concrete boards, post-poured concrete composite layers and post-poured concrete joint core areas. Carbon fiber reinforced plastic (CFRP) prestressed tendons are adopted as the prestressed tendons, and the prestressed tendons are distributed in a curve-shaped mode and constructed in a partially-bonded mode. The prestressed tendons are constructed through a post tension process and penetrate through the joint core areas. Lower longitudinal bars of every two adjacent precast concrete beams are connected through welding or a sleeve. Upper longitudinal bars of the precast concrete beams are arranged on the composite layers and bound on the site. A plurality of layers of precast columns are adopted for constructing the precast concrete columns. The precast concrete beams and the precast concrete columns are connected with the post-poured concrete joint core areas through the post-poured concrete composite layers. All the precast concrete columns, the precast concrete beams and the precast concrete boards in the partially-bonded precast prestressed concrete frame structure can be obtained through standardized production in a factory so that the effect that the partially-bonded precast prestressed concrete frame structure has good stress performance can be ensured, the partially-bonded precast prestressed concrete frame structure has the advantages of being simple in construction, high in construction speed and the like and has wide application prospects in the architectural engineering field.

Description

A Partially Bonded Prefabricated Prestressed Concrete Frame Structure

technical field

The invention belongs to the technical field of civil engineering, and in particular relates to a partially bonded prefabricated prestressed concrete frame structure.

Background technique

The prefabricated prestressed frame structure system refers to the structural system formed by applying prestress to the nodes and frame beams on the basis of the prefabricated concrete frame structure. The frame structure system can achieve a large span, and the construction speed is fast, the quality is good, and a large amount of templates and supports can be saved. It is a structural system that meets the needs of industrialization development and can realize energy saving and structural integration.

The existing prefabricated prestressed frame structure systems include the world structure system, the PRESSS system and the preloaded prefabricated concrete frame structure system. The world structure system is composed of precast concrete columns, pretensioned prestressed composite beams, and precast concrete slabs connected by cast-in-place concrete. In this system, the prestressed tendons do not pass through the core area of the joints, forming an overall prestressed system. The PRESSS system uses post-tensioned unbonded prestressed tendons and ordinary steel bars for connection. The prestressed tendons pass through the prestressed tendon channel reserved at the longitudinal axis of the beam to connect the beams on both sides of the column together. The beam-column joint Fill with mortar. Ordinary steel bars pass through the columns through the holes reserved at the positions of the upper and lower longitudinal bars of the beams, and are grouted on site. The prestressed tendons of this system are arranged in the middle of the beam section, and it is difficult to give full play to their contribution to the structural bearing capacity. In addition, unbonded prestressed tendons are prone to progressive collapse of the structure due to anchor failure. The prestressed prefabricated concrete frame structure system is a prefabricated prestressed concrete frame structure formed by post-tensioning, multi-segment, unbonded linear prestressing tension. The prestressed tensioning construction of this system is complex, and the unbonded prestressed tendons are prone to continuous collapse of the structure caused by anchorage damage.

Aiming at the problems existing in the current prefabricated prestressed concrete frame structure, the present invention proposes a prefabricated prestressed frame system. The system adopts post-cast integral connection, and prefabricated concrete beams, columns, and slab components form reliable connections through cast-in-place concrete and prestress. The lower longitudinal reinforcements of adjacent precast concrete beams are connected by welding or sleeves, and the upper longitudinal reinforcements of precast concrete beams are arranged in the superimposed layer and bound on site. Precast concrete columns are constructed using multi-layer precast columns. The prestressed tendons are constructed by post-tensioning technology and pass through the core area of the joint. The prestressed tendons are made of carbon fiber reinforced plastic (CFRP) prestressed tendons, and the prestressed tendons are arranged in a curved shape according to the design internal force to improve the application efficiency of the prestressed tendons. The prestress adopts a partially bonded structure, that is, the prestressed tendon is covered with a plastic sleeve embedded with butter in the area close to the node, and after the prestressed tendon is stretched, it is grouted to form a non-bonded joint in the area near the node. , Other areas are partly bonded structure with bonding. A series of experimental studies done by the inventors have shown that this structure combines the advantages of both unbonded and fully bonded forms of bonding, has a higher bearing capacity, and at the same time improves the ductility and deformation capacity of the structure.

The partially bonded prefabricated prestressed concrete frame structure proposed by the invention has good seismic performance, conforms to the development strategy of green buildings and industrialized buildings in my country, and has very broad application prospects.

Contents of the invention

The purpose of the present invention is to develop a partly bonded prefabricated prestressed concrete frame structure that not only meets the overall performance requirements, but also has good seismic performance, and at the same time meets the needs of large indoor space, saves materials, and is convenient for construction.

The present invention proposes a partially bonded prefabricated prestressed concrete frame structure, the frame structure is composed of several prefabricated concrete columns 2 and several prefabricated concrete beams 3, and also includes prestressed tendons 1, post-cast concrete The laminated layer 5 and the post-cast concrete joint core area 6, several precast concrete columns 2 and several precast concrete beams 3 are connected through the post-cast concrete laminated layer 5 and the post-cast concrete joint core area 6; A prestressed tendon 1 is provided, and the prestressed tendon 1 is constructed by a post-tensioning process, and passes through the post-cast concrete joint core area 6; the prestressed tendon adopts a curved structure to improve the application efficiency of the prestressed tendon 1; the prestressed tendon 1 Partial bonded structure is adopted, that is, the prestressed tendon 1 is covered with a plastic sleeve embedded with butter in the area close to the core area 6 of the post-cast concrete joint, and after the prestressed tendon 1 is stretched, it is grouted, that is, the post-stressed tendon is formed. The area of the core area 6 of the poured concrete node is unbonded, and the other areas are partially bonded structures with bonding.

In the present invention, the prefabricated concrete column 2 adopts a multi-layer column structure, and the adjacent precast concrete columns adopt a staggered arrangement during the on-site assembly process, so that the reserved longitudinal reinforcement and prefabricated beam can be well realized when the prefabricated beam is hoisted in place. A problem with columns colliding and not seating.

In the present invention, in the multi-layer column structure, the bottom surface of the upper precast concrete column is provided with a grouting air guide groove, and an air vent 10 is left in the center, so that when the post-cast concrete laminated layer 5 is poured, the upper layer The air at the bottom of the precast concrete column is discharged through the PVC pipe embedded in the precast concrete column. The cross section of the grouting air guide groove is triangular, the length of the bottom side is 15mm~25mm, the height is 10mm~15mm, and the diameter of the air vent is 10mm~15mm .

The beneficial effects of the present invention are:

1. The prefabricated prestressed concrete frame proposed by the present invention has the advantages of fast construction speed, low environmental pollution, saving construction period and formwork, and meets the needs of housing industrialization.

2. Experimental research shows that the prefabricated prestressed concrete frame proposed by the present invention has good integrity and anti-seismic performance.

3. In the present invention, the prestressed tendons are partially bonded, which can combine the advantages of both non-bonded and fully bonded bonding forms, have a higher bearing capacity, and improve the ductility and deformation capacity of the structure at the same time.

4. In the present invention, the prefabricated column adopts a multi-layer column structure, and adopts a two-layer prefabricated scheme. During the on-site assembly process, the adjacent multi-storey columns are arranged in staggered layers, which can well solve the problem that the reserved steel bars collide with the precast columns when the prefabricated beams are hoisted in place and cannot be in place.

5. In the present invention, a grouting air guide groove is arranged on the bottom surface of the upper precast concrete column, and an air vent is left in the center. During the sleeve grouting process, the air in the seat slurry layer passes through the air guide groove, enters the pre-embedded PVC pipe through the central vent hole, and finally discharges out of the column. Experimental research shows that setting the grouting air guide groove can effectively dredge the gas and ensure the grouting density of the seat grout layer.

Description of drawings

Fig. 1 is a schematic diagram of a two-story two-span structure of the present invention.

Fig. 2 is a schematic diagram of nodes in a partially bonded prefabricated prestressed concrete frame according to the present invention.

Fig. 3 is a schematic cross-sectional view of a partially bonded prefabricated prestressed concrete composite beam of the present invention.

Fig. 4 is a schematic cross-sectional view of a partially bonded prefabricated prestressed concrete column according to the present invention.

Fig. 5 is a schematic diagram of the grouting air guide groove on the bottom surface of the upper precast concrete column of the present invention.

Fig. 6 is a schematic diagram of assembling a partially bonded prefabricated prestressed concrete frame according to the present invention.

Numbers in the figure: 1 is prestressed tendon, 2 is precast concrete column, 3 is precast concrete beam, 4 is precast concrete slab, 5 is post-cast concrete laminated layer, 6 is post-cast concrete node core area, 7 is grouting guide Air groove, 8 is air vent.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Example 1:

Fig. 1 is a two-story two-span prefabricated prestressed concrete frame structure, in which precast concrete columns 2 and precast concrete beams 3 are connected by post-cast concrete lamination layer 5 and post-cast concrete node core area 6. The prestressed tendon 1 adopts a partly bonded structure, adopts an unbonded form near the joint area, and adopts a bonded form with the rest of the concrete. The prestressed tendon 1 is arranged in a curved line, and the line shape is a multi-section parabola, and it is arranged near the tensile edge at the control section.

Fig. 2 is a detailed diagram of the joint structure in the prefabricated prestressed concrete frame. The precast concrete column 2 and the precast concrete beam 3 are connected through the post-cast concrete lamination layer 5 and the post-cast concrete node core area 6 . The prestressed tendons 1 are partly bonded, unbonded in the area near the node, and bonded to the rest of the concrete. The prestressed tendon 1 is arranged in a curved line, and the line shape is a multi-section parabola, and it is arranged near the tensile edge at the control section. The lower longitudinal reinforcements of adjacent precast concrete beams are connected by welding or sleeves, and the upper longitudinal reinforcements of precast concrete beams are arranged in the post-cast concrete lamination layer 5 and bound on site; the precast concrete columns 2 are constructed of multi-layer columns.

Fig. 3 is a schematic cross-sectional view of a prefabricated prestressed concrete composite beam. The lower longitudinal reinforcements of adjacent precast concrete beams 3 are connected by welding or sleeves. Lashing on site.

Figure 4 is a schematic cross-sectional view of a prefabricated concrete column.

Fig. 5 is a schematic diagram of the grouting air guide groove on the bottom surface of the precast concrete column 2 on the upper floor. The bottom surface of the upper precast concrete column 2 is provided with a grouting air guide groove 7, and an air vent 8 is left in the center so that the air at the bottom of the precast concrete column 2 can be discharged through the PVC pipe embedded in the precast concrete column 2. The cross-section of the grouting air guide groove 7 is triangular, the length of the base is 15mm-25mm, the height is 10mm-15mm, and the diameter of the vent hole is 10mm-15mm.

Figure 6 is a schematic diagram of the assembly of a partially bonded prefabricated prestressed concrete frame structure. The adjacent prefabricated multi-storey columns adopt a staggered assembly scheme, which can avoid the collision between the longitudinal reinforcement reserved in the prefabricated beam and the prefabricated column, which will cause the problem that the prefabricated beam cannot be hoisted in place.

The manufacture process of the present invention is as follows:

Preparation process: complete the production of precast concrete columns, precast concrete beams, and precast concrete slabs in the precast concrete component factory, and number and transport each component to the construction site.

Construction process: a. First put the precast columns in place, install several precast concrete columns adjacent to the column network, and connect the precast concrete columns to the foundation with sleeves; b. Install precast concrete beams at the installation site of the precast concrete columns, Concrete beams are erected on the precast concrete columns and supports, and the precast concrete beams are adjusted horizontally to align with the precast concrete columns; c. Place the precast concrete slabs, place the precast slabs on the prefabricated beams and supports, and control the precast slabs and the precast concrete slabs. The lap length of prefabricated beams and the overall size of prefabricated slabs; d. The vertical steel bars at the bottom of the beams in the core area of the butt-welded joints, and then the stirrups in the core area of the joints are bound, and metal bellows are placed at the predetermined positions in the core area. For the unbonded section The prestressed steel strands are treated without bonding, and the prestressed steel strands are threaded, the longitudinal steel bars on the top of the beam are bound, and the steel bars distributed in the laminated slab are bound; e. Install the formwork for the core area of the node, and pour the core area of the node and the laminated layer on site; f. When the strength of the post-cast concrete in the core area of the node and the superimposed layer reaches 75% of the design strength, the steel strand is stretched. After the steel strand is stretched to the specified tension, hold the load and calculate the retraction value of the anchorage , and then hypertension the steel strand. After the tensioning is completed, use plain concrete grout to seal the anchorage. After the plain concrete hardens, grout through the reserved grouting holes; g. By analogy, the construction of the prefabricated prestressed frame structure can be completed.

Claims (3)

1. A partially bonded prefabricated prestressed concrete frame structure, the frame structure is composed of several prefabricated concrete columns (2) and several prefabricated concrete beams (3), and also includes prestressed tendons (1) , post-cast concrete laminated layer (5) and post-cast concrete joint core area (6), characterized in that: several precast concrete columns (2) and several precast concrete beams (3) pass through the post-cast concrete laminated layer ( 5) It is connected with the post-cast concrete node core area (6); precast concrete beams (3) are provided with prestressed tendons (1), and the prestressed tendons (1) are constructed by post-tensioning technology and pass through the post-cast concrete The core area of the joint (6); the prestressed tendon adopts a curved structure to improve the application efficiency of the prestressed tendon (1); ) in the area of the prestressed tendon (1) is covered with a plastic sleeve embedded with butter, and the prestressed tendon (1) is grouted after the stretching is completed, that is, it is formed in the area of the core area (6) of the post-cast concrete node. Partially bonded construction with no bonding and bonding in other areas. 2. The prefabricated prestressed concrete frame according to claim 1, characterized in that the prefabricated concrete columns (2) adopt a multi-layer column structure, and the adjacent prefabricated concrete columns adopt a staggered arrangement during the on-site assembly process, so that it can be easily To better realize the problem that the reserved longitudinal reinforcement collides with the prefabricated column when the prefabricated beam is hoisted in place and cannot be put in place. 3. The prefabricated prestressed concrete frame according to claim 2, characterized in that in the multi-layer column structure, the bottom surface of the precast concrete column positioned at the upper floor is provided with a grouting air guide groove, and an air vent (10 ), so that when pouring the concrete composite layer (5), the air at the bottom of the precast concrete column on the upper floor is discharged through the PVC pipe embedded in the precast concrete column. 15mm~25mm, height 10mm~15mm, vent hole diameter 10mm~15mm.