CN102505760A

CN102505760A - Prefabricated combined beam and column node member

Info

Publication number: CN102505760A
Application number: CN2011103647768A
Authority: CN
Inventors: 潘金龙; 许准; 袁方
Original assignee: Southeast University
Current assignee: Southeast University
Priority date: 2011-11-17
Filing date: 2011-11-17
Publication date: 2012-06-20
Anticipated expiration: 2031-11-17
Also published as: CN102505760B

Abstract

The invention relates to a prefabricated combined beam and column node member. The prefabricated combined beam and column node member comprises a cross beam and a vertical column which are intersected, wherein the cross beam as well as the vertical column comprises an ECC (engineered cementitious composite) material, longitudinal bars and stirrups, and a rectangular region where the cross beam and the vertical column are intersected and superposed is in the transverse width of A and the longitudinal height of B; the cross beam is in the transverse width of 2B plus A and the longitudinal height of B, and the longitudinal bars penetrate the full length of the cross beam and extend out of two beam ends by 10cm-15cm; and the vertical column in the longitudinal height of 2A plus B, and the longitudinal bars penetrate the full length of the vertical column and extend out of the two column ends by 10cm-15cm. The prefabricated combined beam and column node member disclosed by the invention is the prefabricated member which is formed by casting the steel bar-reinforced ECC material and is applied to an anti-seismic key part, in particular to a key node. Compared with an ordinary reinforced concrete member, the prefabricated combined beam and column node member can significantly improve the ductility and the anti-seismic performance of the structure, greatly reduce the use of the stirrups at the node under the condition of meeting the anti-seismic requirement and solve the difficult problem in construction caused by too dense stirrups in a node region.

Description

A kind of prefabricated combination beam column node component

Technical field

What the present invention relates to is a kind of prefabricated beam column node component of fiber cement based composites (ECC) that adopts reinforcing bar to strengthen, and belongs to novel primary structure member, is mainly used in the earthquake height and sets up defences the district in order to substitute traditional cast-in-situ steel reinforced concrete node.

Background technology

ECC (engineered cementitious composites, engineering is used the fiber cement based composites) be a kind of be filler with cement and fine sand, add the novel concrete based composites that synthetic fibers form then.A large amount of physics and Mechanical Properties achievement show that the ECC material not only has the toughness of superelevation, and stronger energy absorption capability is arranged.And, to test verifiedly, the ultimate tensile strength value of this material is approximately about 100～300 times of common concrete material, is about 5～10 times of reinforcing bar, and its value can surpass 3%, and this provides new thinking for solving the concrete cracking problem.

The beam column mid-side node and the near zone of frame construction will bear very big internal force under geological process; Large amount of building all is to damage because of the destruction of beam column end plastic hinge or joint cores in the Wenchuan earthquake; And general structure (framework, shear wall structure etc.) is in order to realize the seismic design notion and the requirement of " strong column and weak beam ", " strong shear capacity and weak bending capacity " and " strong node "; All disposed fine and close stirrup at concrete beam, post and bean column node place thereof, prevented the shear failure of beam column, but fine and close stirrup has brought great difficulty to site operation; Cause node or key position concrete vibrating leakiness easily, bring potential safety hazard.

In addition; In the practice of construction process, reinforcing bar usually is connected with Type of Welding between prefabricated node and the adjacent members, because end reinforced out-of-shape; Two joints are difficult for alignment; And steel bar end lacks stable support location during butt welding, causes the pad quality usually can't guarantee, becomes the weak spot of structure.

Summary of the invention

Technical problem: the invention provides and a kind ofly improve building structure especially mid-side node zone ductility and energy-dissipating property, thus the prefabricated combination beam column node component that the implementation structure anti-seismic performance improves.

Technical scheme: a kind of prefabricated combination beam column node component of the present invention; Comprise the crossbeam and the column that intersect; Said crossbeam and column are formed with fiber cement based composites, vertical muscle and stirrup by engineering; The transverse width of the rectangular area of crossbeam and column cross-coincidence is A, highly is B vertically;

The transverse width of said crossbeam is 2B+A,, highly be B vertically, said vertical muscle runs through the crossbeam total length and stretches out two beam-ends 10cm～15cm;

Vertical height of said column is 2A+B, and vertical muscle runs through the column total length and stretches out two styletable length 10cm～15cm.

Among the present invention, the end of crossbeam and column all is fixed with angle bar, said angle bar and reinforcing bar welding, and the length that angle bar puts in crossbeam and the column is 10～15cm, and the length that exceeds vertical muscle end is 10～15cm.

The present invention considers each regional loading characteristic of frame construction, at joint cores and near zone utilization ECC material, designs framework and uses prefabricated bean column node, and final and reinforcing bar forms the R/ECC combined member jointly.

Beneficial effect: the present invention has compared following advantage with existing cast-in-situ concrete beam column node:

1. joint cores and near zone are the main position of geological process lower stress; Mainly born the effect of absorption and dissipation seismic energy, adopt the ECC material after piece table revealed higher ductility and good energy-dissipating property, experimentize in the comparison traditional reinforced concrete beam column mid-side node with identical reinforcement ratio and R/ECC being made up bean column node; Each item antidetonation index of the present invention all shows clear superiority; What Fig. 2 represented is R/ECC combined joint and the skeleton curve of common RC node under low all cyclic loadings, and the R/ECC combined joint has improved 20% than the ultimate bearing capacity of common RC node, and displacement improves 15% during destruction; Can find out that by skeleton curve the R/ECC combined joint is after reaching the limit of load; Supporting capacity does not descend rapidly, but longer descending branch is more stably arranged, and this is because the ECC material has high tenacity; Can suppress carrying out of crack, guarantee that node still has bigger bearing capacity and deformability after surrender.

2. node is the main position that absorbs seismic energy in earthquake, so the energy-dissipating property of node will directly influence the anti-seismic performance of structure.What represent like Fig. 3 curve is to do the time spent receiving the earthquake cyclic loading; The accumulation energy consuming ratio of two kinds of nodes; The seismic energy that the R/ECC combined joint absorbs under geological process is the several times of common RC node, has proved absolutely the characteristics of R/ECC combined joint high ductility, highly energy-consuming.

3. be the loop wire stiffness variation curves of two kinds of combined joints under geological process like Fig. 4; The rigidity degeneration of experiment structure can be got with the loop wire rigidity under the one-level distortion and represented; The node rigidity that can be known employing ECC material by figure will obviously be better than the ordinary concrete node; And descend comparatively mild at the later stage of CYCLIC LOADING curve; This just explains that the ECC material makes that through limiting the node crack and delaying stiffness degradation the strength degradation in node later stage also is able to lag behind, and lets node under bigger distortion, keep due bearing capacity, thereby improves the ductility of node.

4. experimental study shows; The steel concrete node has finally reached destruction of a node under low all cyclic loading effects; R/ECC node with same reinforcement ratio then finally shows as beam-ends and destroys, and has reached earthquake resistant code desired " strong node " and beam-ends mode of failure.The R/ECC combined joint is in joint cores; Use just can be satisfied the earthquake resistant code requirement than steel concrete node stirrup still less; This has explained that the ECC material realized and the common shearing resistance of node stirrup in joint cores; Replace the effect of stirrup on the certain degree, used stirrup still less then can solve the overstocked construction difficult problem of node area stirrup effectively.

5. in work progress, the pad quality between the reinforcing bar usually can't guarantee, becomes the weak spot of structure.The present invention has welded angle iron in terminal bar splice place of beam and column, and reinforcing bar can be considered and rests on the angle iron, and stability and fastness when so just having improved with adjacent steel bar butt welding have guaranteed rigidity and welding quality here.

6. the bellows-shaped that forms of beam and column end section has increased contact area, will help in the work progress and the combining of adjacent members, and avoids becoming stressed weakness zone here.

7. prefabricated ECC node is as the key position of frame construction; Compare with cast-in-place steel concrete node, the controlled more easily and assurance of quality in manufacturing process, steel mesh reinforcement is intensive when having solved the construction of cast-in-place node place; The difficult problem that concreting is unreal, the node section good integrity.When mounted, can well be connected again with on every side cast-in-situ concrete, stressed jointly.In addition, adopt this prefabricated units can practice thrift reinforcing bar and template, satisfy the development trend of energy-conserving and environment-protective.

8. because receive the bridge linking effect of fiber in the ECC material, structure showed as multiple cracking and carries out in low class of loading effect following time; And crack width is minimum, appears fine and closely woven nettedly at node, does not occur major fracture all the time; After being applied in the actual engineering, when the R/ECC combined joint when receiving low earthquake intensity geological process, the crack width of core space and near zone thereof will be significantly less than the ordinary reinforced concrete node; Being almost naked eyes can not see, therefore after shake, need not to repair can continue to use.

9. the present invention has also expanded to the utilization of this material of ECC the beam-ends and the styletable plastic hinge region of nearly core space; Under geological process; These zones receive bigger moment of flexure, and the crack at first is to occur herein, develop, finally when certain bar major fracture extends to certain width; Bearing capacity reduces rapidly, and component failure is destroyed.In this zone, the microcrack characteristics of carrying out of ECC material will be able to performance, and this will delay the major fracture time of occurrence, prolong member in the time than work under the high-bearing capacity, improve the ductility and the energy-dissipating property of structural entity.

10.ECC be flyash more than 70% in the material; Be mainly derived from the waste residue behind the coal combustion of steam power station; Therefore the ECC material is a kind of environmental friendliness type material thus; It builds the prefabricated component that forms also is the twice laid to flyash, when guaranteeing the superior performance of member, arrives reusing natural resource.

Description of drawings

Fig. 1 is a sectional view of the present invention;

Fig. 2 is a side sectional view of the present invention, and a is that angle bar puts in the length in the crossbeam among the figure, and b runs through the length of stretching out styletable behind the crossbeam for vertical muscle, and c is the length that angle bar exceeds vertical muscle portion;

Fig. 3 is the end cross-section of crossbeam of the present invention and column;

Fig. 4 is the skeleton curve comparison diagram of the present invention and ordinary reinforced concrete node;

Fig. 5 is the accumulative total power consumption curve comparison diagram of the present invention and ordinary reinforced concrete node;

Fig. 6 is the loop wire stiffness curve comparison diagram of the present invention and ordinary reinforced concrete node.

Have among the figure: crossbeam 1, column 2, vertical muscle 3, stirrup 4, angle bar 5.

The specific embodiment

Prefabricated combination beam column node component of the present invention comprises the crossbeam 1 and column 2 that intersect, and said crossbeam 1 is formed by ECC material, vertical muscle 3 and stirrup 4 with column 2, and crossbeam 1 is A with the transverse width of the rectangular area of column 2 cross-coincidences, highly is B vertically; The transverse width of crossbeam 1 is 2B+A,, highly be B vertically, said vertical muscle 3 runs through crossbeam 1 total length and stretches out two beam-ends 10cm～15cm; Vertical height of column 2 is 2A+B, and vertical muscle 3 runs through column 2 total lengths and stretches out two styletable length 10cm～15cm.

Among the present invention, the end of crossbeam 1 and column 2 all is fixed with angle bar 5, and said angle bar 5 and reinforcing bar 3 welding, angle bar 5 put in crossbeam 1 and be 10～15cm with column 2 interior length, and the length that exceeds vertical muscle 3 ends is 10～15cm.

The preparation process of the prefabricated combination beam column of the present invention node component is:

1. confirm the value size of A and B according to designing requirement, make mould, the good reinforcing bar of colligation, making reinforcing bar stretch out mould ends length is b, and then at end reinforced welding angle iron, it is a that angle iron gos deep into die length, and exceed steel bar end length is c.

2. insert corrugated sheet in mould middle cross beam and post end, and the length that makes angle iron pass corrugated sheet is b+c, pours into the ECC material then, and carefully vibrate, the final set corrugated sheet of dismantling later on, maintenance can form prefabricated component after 28 days.

In the actual installation engineering of building operations; Use the reinforcing bar connection between two prefabricated combination beam column node components of the present invention; In the end of two prefabricated combination beam column node components, all closely weld with reinforcing bar the termination of vertical muscle 3, and the reinforcing bar that stretches into also closely welds with angle bar simultaneously; Then at the cast-in-place ordinary concrete of linkage section of two prefabricated combination beam column node components, until moulding.

Claims

1. prefabricated combination beam column node component; It is characterized in that; Comprise the crossbeam (1) and the column (2) that intersect; Said crossbeam (1) and column (2) are formed with fiber cement based composites, vertical muscle (3) and stirrup (4) by engineering, and crossbeam (1) is A with the transverse width of the rectangular area of column (2) cross-coincidence, highly is B vertically;

The transverse width of said crossbeam (1) is 2B+A,, highly be B vertically, said vertical muscle (3) runs through crossbeam (1) total length and stretches out two beam-ends 10cm～15cm;

Vertical height of said column (2) is 2A+B, and vertical muscle (3) runs through column (2) total length and stretches out two styletable length 10cm～15cm.

2. a kind of prefabricated combination beam column node component according to claim 1; It is characterized in that; The end of crossbeam (1) and column (2) all is fixed with angle bar (5); Said angle bar (5) and reinforcing bar (3) welding, the length that angle bar (5) puts in crossbeam (1) and the column (2) is 10～15cm, and the length that exceeds vertical muscle (3) end is 10～15cm.