Background technology
At present, the frame column as the main member of frame construction is generally common reinforced concrete post.But since can't solve since the sectional dimension of frame column often greater than the thickness of body of wall, in use, the partly phenomenon of outstanding body of wall of pillar appears in indoor meeting, thereby has influenced indoor space and use.
In order to address this problem, the form of structure of shaped rc columns has appearred.For the reinforced concrete special-shape column structure, mainly contain T, L, cross, as shown in Figure 1, scholar both domestic and external has carried out extensive, deep research.Its theory basically forms, and writing of the local rules that provinces and cities such as Tianjin, Shenyang, Guangdong, Shanxi have finished and guides in engineering practice, and building area reaches number with ten million square metre.Wherein domestic many scholars, the expert who carries out this respect research once obtained the scientific and technological reward of many governments.
But, also find under study for action: the ductility ratio ordinary rectangular post of shaped rc columns poor.Hetermorphiscal column is owing to the existence of many limbs, and its centre of shear does not often overlap with the cross section centre of form, and under stress, each limb produces warpage normal stress and shear stress.Because shear stress makes post limb concrete the crack occur prior to the ordinary rectangular post, promptly produces the abdomen shear crack, causes hetermorphiscal column fragility obvious, and the deformability of hetermorphiscal column is reduced than ordinary rectangular post.
As the safeguard measure of hetermorphiscal column ductility, necessary strict Control Shaft pressure ratio avoids high long ratio less than 4 (short columns) simultaneously.The purpose of control column section ratio of axial compressive force to axial compressive ultimate capacity of section is to require post should have enough big sectional dimension, destroys to prevent little bias voltage, improves the deformability of post, satisfies shockproof requirements.Therefore, in the various rules, the ratio of axial compressive force to axial compressive ultimate capacity of section of special-shape column has all been carried out strict restriction, generally the limit value of axial compression ratio than the existing earthquake resistant code regulation of country is low.This has limited the development of special-shape column structure undoubtedly.Therefore the ductility and the bearing capacity that how to improve the special-shape column structure are the task of top priority.
For addressing this problem, China's utility model patent has provided " a kind of novel steel tube concrete column " for No. 99236299.7, wherein being used for the concrete steel pipe of filling is the special-shaped thin wall steel pipe, be provided with binding bar on each limit of special-shaped thin wall steel pipe, described special-shaped thin wall steel pipe can be square, L shaped or T shape thin-wall steel tube, the minimum length of side 〉=the 150mm of special-shaped thin wall steel pipe, wall thickness 〉=8mm; The spacing that binding bar is set is 100~200mm; The slenderness ratio of the post ratio of smallest cross-sectional width (length with)≤30.Though this steel core concrete column has solved the single problem of existing concrete filled steel tube post shapes, exist binding bar need be set, construction has the shortcoming of inconvenience more.
I am the patent " a kind of steel reinforced high strength concrete column; patent No. ZL200520090306.7 " of application once, purpose is because the number of plies of building is more and more, more and more higher, the employed concrete strength grade of depth of building is more and more higher at current, and the ductility of high-strength concrete is relatively poor, influence the problem of the anti-seismic performance of structure, theory in conjunction with known steel reinforced high strength concrete, structure to existing steel reinforced high strength concrete column is improved, and provides a kind of novel special-shaped steel reinforced high strength concrete column.The section form of this special-shaped steel reinforced high strength concrete column changes with the relation of post and wall, not only solve the shortcoming of existing reinforcing bar high-strength concrete column poor seismic behavior, but also the section form and the research contents of combined steel and concrete column have been enriched, has the bearing capacity height, rigidity is big, in light weight, plasticity, good toughness, characteristics such as shock resistance and anti-fatigue performance are good, anti-seismic performance is good.But exist the problem of construction inconvenience equally, especially for column section when less than normal, more outstanding.
The scholar who has has proposed hetermorphiscal column as shown in Figure 2, is open web type steel reinforced concrete hetermorphiscal column.This kind post can improve the bearing capacity and the ductility of post, is a kind of novel frame column.The scholar who has has proposed square steel pipe concrete profiled pile as shown in Figure 3, and this kind post is made up of square steel pipe and purlin, is a kind of novel post equally.
The research of concrete filled steel tube starts from 1897 abroad, American John Lally invention in steel pipe fill concrete as the load-bearing pillar of building construction.Before and after the twenties, there has been more deep understanding external various countries to concrete filled steel tube, have built a large amount of buildings in eighties of last century.Before and after the sixties in 20th century, encased structures technology developed country abroad comes into one's own, and has carried out a large amount of research.
The big quantity research of concrete filled steel tube mainly starts from later stage seventies of eighties of last century in China, and the theory of concrete filled steel tube has been carried out deep research, and guides the application of engineering.China has issued " encased structures design and construction rules " (CECS28:90) in nineteen ninety.
In " encased structures ", steel core concrete column can be divided into steel core concrete column and steel pipe the steel core concrete column post in of steel pipe in the post outside, and the former is commonly referred to steel core concrete column, and the latter is commonly referred to the concrete filled steel tube coupled column.In steel core concrete column, core concrete has not only improved its elastic property in operational phase under the constraint of steel pipe, and has very big plastic strain when destroying.Compare with reinforced concrete post, adopt steel core concrete column not have operations such as assembling reinforcement, formwork and form removal, easy construction, because of managing interior no-reinforcing-bar, pouring is easy, vibration compacting.Compare with steel structure member, the structure of concrete filled steel tube is simpler than steel structure member usually, and weld seam is few, is easy to make.But because the steel pipe of steel core concrete column needs problems such as fire prevention, antirust processing, so when building highrise building, its maintenance cost is higher.
The form of concrete filled steel tube coupled column is seen Fig. 4.In the concrete filled steel tube coupled column, the concrete in the steel pipe is generally high-strength concrete, and its strength grade is generally equal to or is higher than the outer strength grade of concrete of steel pipe.Because steel pipe provides effect of contraction to the concrete of core space, has produced the sleeve effect, so the concrete filled steel tube coupled column can increase the energy dissipation capacity of structure, the whole anti-seismic performance of raising building, its energy dissipation capacity is apparently higher than general reinforced concrete post.
The steel duct strength grade of concrete is higher than outside situation, and the principle of employing superposed column designs and constructs.Fig. 4 promptly at first at high core column of compressive strength of post internal production, bears the load at structure construction initial stage by it.After treating that a certain height is arrived in main structure construction, build the steel pipe peripheral concrete again, therefore be also referred to as superposed column.In superposed column, the part vertical load of structure will be born by core column, another part vertical load is born by the post peripheral concrete, its ratio of axial compressive force to axial compressive ultimate capacity of section is less, thereby make pillar have ductility preferably, reach the purpose of improving the High Strength Concrete Structures anti-seismic performance, its achievement in research successfully is applied among nearly 30 highrise buildings.
By analysis with relatively find, more than several hetermorphiscal column all exist many deficiencies.If but the concrete filled steel tube coupled column of shaped rc columns and Fig. 4 is integrated, study a kind of special-shaped steel pipe concrete-core column, one improves the deficiency of present shaped rc columns surely.
Summary of the invention:
The objective of the invention is to: shaped rc columns and concrete filled steel tube coupled column are integrated, study a kind of special-shaped steel pipe concrete-core column, improving the deficiency of present shaped rc columns, and form a whole by concrete.
The objective of the invention is to be achieved through the following technical solutions
Special-shaped steel pipe concrete-core column, the section form of post are T, L, cross, and round steel pipe is positioned at steel concrete inside, and in the crossover sites of both direction steel concrete in length and breadth;
Described special-shaped steel pipe concrete-core column, its stem stem normal section bearing capacity is formed by three partial stacks, is respectively the closing of stack of the bearing capacity of concrete part, reinforcing bar part, steel tube concrete core pillar three parts.
Advantage of the present invention and effect are:
1. steel pipe is positioned at the inside of direction steel concrete crossover sites in length and breadth, can be fire-resistant, corrosion-resistant;
2. can pour into a mould the concrete of steel duct earlier, the outer concrete of surveying of back cast steel pipe, thus form superposed column;
3. because the existence of steel pipe has improved the ductility of post, improve the bearing capacity of post, be beneficial to the earthquake zone seismic design.
The specific embodiment
The present invention is described in detail with reference to the accompanying drawings.
Fig. 1~4 are correlation technique, and the literal among the figure is unintelligible, do not influence the understanding of the present invention.
The abnormity that this place is carried is meant that the section form of post is T, L, cross, and steel pipe remains circular.
The stem stem normal section bearing capacity is formed by three partial stacks, is respectively the closing of stack of the bearing capacity of concrete part, reinforcing bar part, steel tube concrete core pillar three parts.
Concrete design formulas is:
In the formula: N is an axle power design load; is the influence coefficient of steel tube concrete core pillar bearing capacity; A
Ci, σ
CiBe the area and the stress of i concrete unit; A
Sj, σ
SjBe the area and the stress of j reinforcing bar; A
Sck, σ
SckBe the area and the stress of k steel tube concrete core pillar unit; n
cUnit number for the concrete division; n
sRadical for reinforcing bar; n
ScUnit number for the steel tube concrete core pillar division.M
x, M
yBe respectively about cross section centre of form axle x
0, y
0The bending moment design load; x
Ci, y
CiBe the centre of form coordinate of i concrete unit under global coordinate system; x
Sj, y
SjBe the centre of form coordinate of j reinforcing bar under global coordinate system; x
Sck, y
SckBe the centre of form coordinate of k steel tube concrete core pillar unit under global coordinate system; x
0, y
0Be the coordinate of the cross section centre of form under global coordinate system.
Fig. 5 is that the cross section is the special-shaped steel pipe concrete-core column schematic diagram of " ten " font structure.Be made up of round steel pipe 2, steel concrete 3 and concrete 1, wherein concrete 1 is positioned at steel pipe 2, and steel pipe is positioned at the steel concrete 3 of direction in length and breadth.
Fig. 6 is that the cross section is the special-shaped steel pipe concrete-core column schematic diagram of " L " font structure.Be made up of round steel pipe 2, steel concrete 3 and concrete 1, wherein concrete 1 is positioned at steel pipe 2, and steel pipe is positioned at the steel concrete 3 of direction in length and breadth.
Fig. 7 is that the cross section is the special-shaped steel pipe concrete-core column schematic diagram of " T " font structure.Be made up of round steel pipe 2, steel concrete 3 and concrete 1, wherein concrete 1 is positioned at steel pipe 2, and steel pipe is positioned at the steel concrete 3 of direction in length and breadth.