CN103821233A - High-damping type steel reinforced concrete joint - Google Patents

Abstract

The invention provides a high-damping steel concrete node, which includes a steel column, and a beam-shaped steel arc-shaped connecting section extending laterally is fixedly connected to the steel-shaped steel column. section, weakened section and section of equal cross-section; the width of the enlarged section gradually increases from the weakened section to the steel column, and the weakened section is weakened from the flange of the beam-shaped steel arc connecting section to the central arc form. The high-damping steel-concrete node provided by the present invention is provided with arc-shaped weakening on the flange of the beam-shaped steel arc-shaped connection section, so that the plastic hinge at the node moves outward, preventing the nonlinear deformation of the plastic hinge area from destroying the core area of the node, The cracking of concrete in the core area is avoided, and the shear resistance capacity of the core area is improved. Because the steel flange at the beam end is weakened to the center arc, high damping concrete is used, which improves the energy dissipation capacity of this part. In addition, because this node adopts the assembled integral connection method, the construction progress of this kind of node is accelerated.

Description

High damping steel concrete joints

technical field

The invention relates to the technical field of steel-concrete composite structures, in particular to a high-damping steel-concrete node.

Background technique

Steel concrete joints have good ductility and energy dissipation capacity. However, under the action of earthquakes, the plastic hinge area of steel concrete joints generally occurs at the beam end, and the nonlinear deformation of the plastic hinge area at the beam end penetrates into the core area of the joint, which will easily increase the stress of the beam-column joint weld and cause weld fracture; in addition, the beam The penetration of the non-linear deformation in the end plastic hinge area to the core area of the joint is also likely to cause cracking of the concrete in the core area of the joint and reduce the shear resistance of the concrete in the core area of the joint.

Contents of the invention

A brief overview of the invention is given below in order to provide a basic understanding of some aspects of the invention. It should be understood that this summary is not an exhaustive overview of the invention. It is not intended to identify key or critical parts of the invention nor to delineate the scope of the invention. Its purpose is merely to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later.

The invention provides a high-damping steel-concrete joint, which is used to solve the problems of concrete cracking in the core area of the joint and poor shear resistance in the existing steel-concrete joint.

The invention provides a high-damping steel concrete node, which includes a steel column, and a beam-shaped steel arc-shaped connecting section extending laterally is fixedly connected to the steel-shaped steel column. section, weakened section and section of equal cross-section; the width of the enlarged section gradually increases from the weakened section to the steel column, and the weakened section is weakened from the flange of the beam-shaped steel arc connecting section to the central arc form.

In the high-damping steel concrete node provided by the present invention, an enlarged section is set at the arc-shaped connecting section of the beam-shaped steel, and the contour includes a straight line part and a weakened section of the arc line part connected at both ends of the straight line part, so that the plastic hinge at the joint Move outward to prevent the nonlinear deformation of the plastic hinge area from damaging the core area of the joint, avoid concrete cracking in the core area, and improve the shear resistance of the core area.

Description of drawings

The above and other objects, features and advantages of the present invention will be more easily understood with reference to the following description of the embodiments of the present invention in conjunction with the accompanying drawings. The components in the drawings are only to illustrate the principles of the invention. In the drawings, the same or similar technical features or components will be denoted by the same or similar reference numerals.

Fig. 1 is the top view of the high damping steel concrete node provided by the embodiment of the present invention;

Fig. 2 is the curved weakening contour diagram of the high damping steel concrete node provided by the embodiment of the present invention;

Fig. 3 is the front view of the high damping steel concrete node provided by the embodiment of the present invention;

Fig. 4 is A-A sectional view of Fig. 3;

Fig. 5 is the B-B sectional view of Fig. 3;

Fig. 6 is the C-C sectional view of Fig. 3;

Fig. 7 is a schematic diagram of the connection between the high damping steel concrete node and the beam provided by the embodiment of the present invention;

Figure 8 is a diagram of the bending moment of the weakened part of the plastic hinge region and the bending moment of the beam end.

Detailed ways

Embodiments of the present invention will be described below with reference to the drawings. Elements and features described in one drawing or one embodiment of the present invention may be combined with elements and features shown in one or more other drawings or embodiments. It should be noted that representation and description of components and processes that are not related to the present invention and known to those of ordinary skill in the art are omitted from the drawings and descriptions for the purpose of clarity.

Fig. 1 is a top view of a high-damping steel-concrete node provided by an embodiment of the present invention. As shown in Figure 1, the high-damping steel concrete joint provided by the embodiment of the present invention includes a steel column 2, and a beam-shaped steel arc connecting section 3 extending transversely is fixedly connected to the steel column 2, and the beam-shaped steel arc connecting section 3 includes a self- The enlarged section, the weakened section and the equal section section extending transversely in turn of the steel column; the width of the enlarged section gradually increases from the weakened section to the steel column, that is, the enlarged end is formed near the end of the steel column, and the weakened section is composed of beam-shaped steel arc The flange 10 of the connecting section (see also FIG. 3 ) is formed by a central arc-shaped weakening 4 .

In actual use, the shaped steel column 2 and the beam shaped steel arc connection section 3 can be, but not limited to, I-shaped steel. Referring also to FIG. 5 , stirrups 14 and longitudinal bars 15 are arranged outside the arc-shaped connecting section 3 of beam-shaped steel in the form of I-steel.

In the high-damping steel concrete node provided by the present invention, an enlarged section is provided on the beam-shaped steel arc connection section 3 and a weakened section is provided on the flange 10 with a contour including a straight line part and an arc line part connected at both ends of the straight line part, The plastic hinge at the node is moved outward, preventing the nonlinear deformation of the plastic hinge area 5 (see Figure 3) from damaging the core area of the node, avoiding concrete cracking in the core area 1 of the node, and improving the shear resistance of the core area 1 of the node. In addition, due to the enlarged section extending laterally from the steel column 2 in sequence, the weakened portion formed by the end of the beam and the arc-shaped weakening 4 forms a difference in bending stiffness, thereby further shifting the plastic hinge region 5 away from the end of the beam.

Also see Figure 2, in order to avoid the non-linear deformation of the plastic hinge area at the beam end from infringing on the core area of the joint, the upper and lower flanges 10 of the I-shaped beam-shaped steel arc connection section are weakened by arc weakening 4, and the arc The contour of the weakened shape 4 includes a straight line part and an arc part connecting two ends of the straight line part.

In Fig. 1, a is the distance a=0.5b _f from the weakened part to the column, which can be determined according to the degree of influence of the plastic hinge area of the weakened part on the beam-column connection weld, and b _f is the width of the beam-shaped steel flange.

The outline of the arc weakening 4 in Fig. 2 includes a straight line part and an arc part connected at both ends of the straight line part, and _c≤0.25bf ; wherein, c is the depth of the arc weakening 4, and the depth of the arc weakening 4 is used To control the position of the plastic hinge in the beam and the magnitude of the bending moment transmitted to the node core area 1.

The design parameters of the maximum weakened position of the steel flange in Fig. 2 need to satisfy formulas (1) and (2).

l≤0.25b _f ; …(1)

In formula (1), l is the length of the horizontal section of the maximum weakened part, which is mainly to control the range of the maximum stress zone, so that the plastic hinge can fully develop within this range and prevent stress concentration at this part.

b=0.75h _b +0.25b _f ; (2)

In formula (2), b is the weakened length, mainly to control the degree of deformation in the plastic hinge area, where h _b is the height of the steel section.

In order to avoid stress concentration at the position where the section of the beam-shaped steel flange changes, this patent adopts an arc transition (as shown in Figure 2) at this position. This arc transition area is a parabolic arc transition, which can be more It is best to avoid stress concentration in this transition area. After repeated finite element calculations, this patent gives the optimal calculation formula for the arc length of the parabola:

$\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.00129</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 0.99955</span>}\mathrm{<span\; class="notranslate">\; Z</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 0.01698</span>}\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2.481439</span>}\frac{{\mathrm{<span\; class="notranslate">\; f</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; L</span>}}\mathrm{<span\; class="notranslate">\; 0.05</span>}<span\; class="notranslate">\; \&le;</span>\frac{\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 0.1</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In the formula (3), F is the arch height of the arc part; L is the arch span of the arc part; s is the arc length of the arc part; b _f is the width of the flange of the beam-shaped steel arc connection section; The arc portion is used for transition. In actual use, the contour line of the arc portion is a parabola, and the use of a parabolic transition can better avoid the problem of stress concentration.

Referring also to FIG. 6 , high damping concrete 11 is poured outside beam-shaped steel arc connecting section 3 , and high damping concrete 11 is located at arc weakening 4 . Pouring high-damping concrete at arc-shaped weakening 4 further enhanced the energy dissipation capacity of the plastic hinge area, and reduced the cracking of the concrete at arc-shaped weakening 4. By setting the arc weakening 4 and pouring high damping concrete at the arc weakening 4, not only the plastic hinge is transferred from the beam end to the weakened position of the beam flange 10, thus avoiding the nonlinear deformation of the plastic hinge area at the beam end causing damage to the joint core area. In addition, due to the pouring of high-damping concrete in the weakened area formed by the arc weakening 4, the energy dissipation capacity of this part is greatly enhanced. subsequent repair work. Furthermore, stirrups 14 and longitudinal ribs 15 are arranged outside the arc-shaped weakening 4 .

The shaped steel column 2 is poured with concrete to form a column, and the distance a between the starting end of the arc-shaped weakening 4 and the column is half the width of the flange 10 of the arc-shaped connecting section of the beam-shaped steel. Lb weakens the distance from the middle part of 4 arcs to the column. Also refer to Fig. 4. Stirrup bars 12 and longitudinal bars 13 are arranged on the outer side of the steel column 2 to improve the strength of the concrete structure.

In actual use, high damping concrete includes the following components by weight: 100 parts of cement; 42 parts of water; 145 parts of sand; 300 parts of stone; PU (polyurethane; Polyurethane)/EP (epoxy resin; Unsaturated polyester; Unsaturated PolyesterResin) polymer 12 parts; graphite 5 parts; high damping fiber 7 parts; silica fume 8 parts; water reducing agent 1 part.

Specifically, the PU/EP/UP polymer includes the following components by weight: 47 parts of PU; 23 parts of EP; 23 parts of UP, so that the PU/EP/UP polymer has wide temperature and high damping characteristics. The dielectric loss factor tanδ>0.6 in the temperature range.

The high damping fiber is a carbon fiber coated with a high damping coating. The coating is made in three steps. The first step is to remove the adhesive layer on the surface of the carbon fiber under the protection of argon; the second step is to use the heating of the reaction gas Decomposition, deposition of decomposition products on the surface of the degummed carbon fiber; the third step is graphitization at high temperature. High damping fibers can be filled into the PU/EP/UP polymer network system to enhance friction between fibers and between fibers and PU/EP/UP polymers, and enhance friction between fibers and PU/EP/UP polymer interfaces. The displacement and the dislocation motion at the interface improve the damping of the highly damped fiber.

Graphite in high damping concrete uses flake graphite filler. The addition of flake graphite filler can expand the damping temperature range and increase the proportion of viscoelastic material components in concrete. The flake graphite filler can increase the friction between the various particles inside the concrete, and internal friction can consume part of the energy.

Silica fume is a very fine powder. The addition of silica fume can cause the cement hydration product to undergo a secondary hydration reaction to form a new gel and have an important impact on its macroscopic physical and mechanical properties.

River sand is the most important material constituting the elastic skeleton of EPS (Expanded Polystyrene; Expanded Polystyrcnc) lightweight aggregate concrete, and it plays an important role together with Portland cement in the mechanical properties (such as compressive strength) of EPS lightweight aggregate concrete. effect. River sand can be, but not limited to, have a bulk density of 1274kg/m3 and a water absorption rate of 1%. The stones in the plastic hinge area can be but not limited to dense granite with edges and corners, the aggregate gradation should be within the required range, and the maximum particle size of the aggregate should be controlled between 10-20mm. The water reducer can be but not limited to UNF-5 non-air-entraining high-efficiency water reducer produced by Tianjin Construction Research Institute.

When configuring the high-damping concrete, first mix cement and sand evenly, then add stones, continue mixing until uniform, then add graphite and silica fume, after mixing evenly, add water and water reducer, and mix for 3-5 Minutes to ensure that the surface of the cement particles is wet. Finally add PU/EP/UP polymer and high damping fiber, stir for 3-5 minutes.

The connection between the shaped steel column 2 and the beam-shaped steel arc-shaped connecting section 3 is the node core area, and the node core area is provided with a T-shaped stiffener 6, and the T-shaped stiffener 6 is fixedly connected to the shaped steel column 2. Specifically, the T-shaped stiffener 6 can be welded on the web of the steel column 2 . By setting the T-shaped stiffener 6 so that it, together with the flange 10 of the steel column 2 and the stirrup framed outside the steel column 2, together form the concrete constraint on the core area 1 of the node, so as to improve the shear strength and strength of the concrete in the core area 1 of the node. ability to deform.

The length extension direction of the T-shaped stiffener 6 is consistent with the length extension direction of the shaped steel column 2 .

Both sides of the weakened section are respectively provided with reinforcement bars, and the reinforcement bars are located between the upper and lower flanges 10 of the arc-shaped connection section of the beam-shaped steel. To prevent lateral buckling at the end of the beam-shaped steel arc connection section of the weakened section, which will affect the rotational performance of the plastic hinge, and can withstand out-of-plane torsion to a certain extent.

The opposite sides of the shaped steel column 2 are provided with beam-shaped steel arc-shaped connecting sections 3, and the outer side of the connection position between the shaped steel column 2 and the beam-shaped steel arc-shaped connecting section 3 is provided with reinforcing steel bars 8, and the reinforcing steel bars 8 are connected from the two beam-shaped steel arc-shaped The middle part of the weakened section of one of the connecting sections 3 extends to the middle part of the weakened section of the other beam-shaped steel arc connecting section 3 . By arranging reinforcing steel bars 8, the amount of reinforcement at the root of the steel column 2 and the beam-shaped steel arc connection section 3 is increased, and the connection strength between the steel column 2 and the beam-shaped steel arc connection section 3 roots is improved, so that the node is damaged during an earthquake. The position is located in the weakened section, which can reduce the degree of damage to the roots of the arc-shaped joints of steel columns and beams caused by earthquakes, and facilitate post-earthquake repairs. In addition, the reinforced steel bars 8 are bent and extended along the beam-shaped steel arc-shaped connecting section 3 and the outer edge of the shaped steel column 2, so as to avoid the reinforcement bars extending in a straight line. If the straight-line extending reinforcing steel bars are provided, unnecessary weakening of the shaped steel columns will occur, which will affect the overall performance. In addition, stiffening ribs 9 are provided on both sides of the weakened section.

As shown in Fig. 7, when high-damping steel concrete joints are used for connection, bolts are used to fix the web of beam 7 to the web of beam-shaped steel arc connection section 3, and then the upper and lower flanges 10 of beam 7 are respectively connected to The upper and lower flanges 10 of the beam-shaped steel arc connection section 3 are welded. Using this connection method can greatly speed up the construction progress.

Table 1

Table 1 shows the equivalent viscous damping coefficients of ordinary steel concrete joints and high damping steel concrete frame joints of the present invention. It can be seen from Table 1 that the equivalent viscous damping coefficient of the joint of the high damping steel concrete frame of the present invention is obviously higher than that of the ordinary steel concrete joint, which shows that adding high damping at the weakened section of the steel flange 10 The concrete increases the damping of the joints, making the energy dissipation capacity of the joints stronger than that of ordinary steel concrete joints, thereby improving the seismic performance of the steel concrete joints weakened by the flange 10 .

梁端（也即靠近型钢柱的端部）的弯矩为为梁型钢弧形连接段靠近型钢柱一端的屈服弯矩；

为梁型钢弧形连接段靠近型钢柱一端到所述翼缘最大削弱处之间的区域的钢筋混凝土的实际屈服弯矩；

为削弱段最大削弱处钢筋混凝土的屈服弯矩，

为两端钢筋混凝土的屈服弯矩；l_a削弱段最大削弱处到加载点的距离；L为加载点到型钢柱的距离，l_b为削弱段最大削弱处到梁端的距离。As shown in Figure 8, if a downward load P is applied to the beam in the direction away from the steel column, then the bending moment at the maximum weakened point is

The bending moment at the end of the beam (that is, near the end of the steel column) is is the yield bending moment of the beam-shaped steel arc connection section near the end of the steel column;

is the actual yield moment of the reinforced concrete in the area between one end of the arc-shaped connection section of the beam-shaped steel column and the maximum weakened point of the flange;

is the yield bending moment of reinforced concrete at the maximum weakened point of the weakened section,

is the yield bending moment of reinforced concrete at both ends; l _a is the distance from the maximum weakened point of the weakened section to the loading point; L is the distance from the loaded point to the steel column; l _b is the distance from the maximum weakened point of the weakened section to the beam end.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (10)

1. A high-damping profiled steel concrete node, comprising a profiled steel column, on which the profiled steel column is fixedly connected with a transversely extending beam profiled steel arc connecting section, characterized in that, said beam profiled steel arc connecting section comprises from the profiled steel column successively transverse Extended enlarged section, weakened section and equal section section; the width of the expanded section from the weakened section to the steel column gradually increases, and the weakened section is from the flange of the arc-shaped connecting section of the beam to the center Arc weakening formed. 2. The high-damping steel-concrete node according to claim 1, wherein the arc-shaped weakened profile includes a straight line part and an arc line part connecting two ends of the straight line part, c≤0.25b _f ; l≤0.25b _f ; b=0.75h _b +0.25b _f ; $\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.00129</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 0.999557</span>}\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 0.016987</span>}\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2.481439</span>}\frac{{\mathrm{<span\; class="notranslate">\; f</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; ;</span>$ $\mathrm{<span\; class="notranslate">\; 0.05</span>}<span\; class="notranslate">\; \&le;</span>\frac{\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 0.1</span>}<span\; class="notranslate">\; ;</span>$ Among them, c is the depth of the arc weakening; F is the arch span of the arc; L is the arch height of the arc; s is the arc length of the arc; b _f is the beam-shaped steel arc connection The width of the segment flange; h _b is the height of the beam-shaped steel arc connecting section; b is the length of the arc; l is the length of the straight line. 3. The high-damping steel-concrete node according to claim 1 or 2, characterized in that, the arc-shaped connecting section of the beam-shaped steel is poured with high-damping concrete, and the high-damping concrete is located at the arc-shaped weakening. 4. The high-damping steel-concrete node according to claim 3, wherein the steel column is poured with concrete to form a column, and the distance between the starting end of the arc weakening and the column is a beam-shaped steel arc connection Half the width of the segment flange. 5. The high-damping steel-concrete joint according to claim 3, wherein the high-damping concrete comprises the following components in parts by weight: 100 parts of cement; 42 parts of water; 145 parts of sand; 300 parts of gravel; PU /EP/UP polymer 12 parts; graphite 5 parts; high damping fiber 7 parts; silica fume 8 parts; water reducer 1 part. 6. The high-damping steel-concrete node according to claim 5, wherein the PU/EP/UP polymer comprises the following components by weight: 47 parts of PU; 23 parts of EP; 23 parts of UP. 7. The high-damping steel-concrete node according to claim 1 or 2, characterized in that the connection between the steel column and the beam-shaped steel arc connection section is a node core area, and the node core area is provided with a T-shaped Stiffeners, and the T-shaped stiffeners are fixedly connected to the shaped steel columns. 8. The high-damping shaped steel-concrete node according to claim 7, wherein the extending direction of the length of the T-shaped stiffener is consistent with the extending direction of the length of the shaped steel column. 9. The high-damping steel-concrete node according to claim 1 or 2, characterized in that reinforcement bars are respectively provided on both sides of the weakened section, and the reinforcement bars are located on the upper and lower wings of the beam-shaped steel arc connection section between the edges, and the reinforcing steel bar is bent and extended along the curved connecting section of the beam-shaped steel and the outer edge of the shaped steel column. 10. The high-damping steel-concrete node according to claim 1 or 2, characterized in that, the beam-shaped steel arc-shaped connecting sections are arranged on opposite sides of the steel column, and the steel column and the beam The outer side of the connection position of the arc-shaped connecting section of the beam is provided with reinforcing steel bars, and the reinforcing steel bars extend from the middle of the weakened section of one of the arc-shaped connecting sections of the beam-shaped steel to the weakened section of the other arc-shaped connecting section of the beam-shaped steel. the middle of the segment.

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