CN105178511B - Section steel flange weakens regeneration concrete energy dissipation coupled column and preparation method thereof - Google Patents

Abstract

The invention discloses a steel flange weakened recycled concrete anti-seismic energy-dissipating composite column, which comprises a steel web, longitudinal reinforcement arranged parallel to the steel web, stirrups arranged along the longitudinal direction of the longitudinal reinforcement and filled therebetween The concrete; the steel web in the middle area of the composite column weakens the flange, the concrete is recycled aggregate concrete, and the replacement rate of waste concrete aggregate is 45-55%. In the present invention, the weakened section steel flange in the middle area of the column can give full play to the performance of the column, and has better rigidity and ductility under the earthquake load, which improves the energy dissipation capacity of the column components and the safety of the structure; the section steel in the middle area of the column Flange weakening effectively improves the compactness of column concrete pouring and helps to improve construction quality.

Description

Steel flange weakened recycled concrete anti-seismic energy-dissipating composite column and its manufacturing method

technical field

The invention belongs to building structural components, in particular to a type steel flange weakened recycled concrete anti-seismic energy-dissipating composite column.

Background technique

Steel-concrete structure is a main form of steel-concrete composite structure. Due to its high bearing capacity, high rigidity, good seismic performance, saving steel, and reducing engineering cost, it has been more and more widely used in long-span structures and earthquakes. High-rise and super high-rise buildings in the district.

With the progress of urbanization in China, the problem of construction waste (waste) has gradually been paid attention to. If a simple stacking method is adopted, the annual construction waste disposal will cover an area of at least 150 million square meters. Recycled concrete as a new material can solve this problem well.

The steel ratio in the steel reinforced concrete structure is much larger than that in the ordinary reinforced concrete structure, so more steel can be configured in a limited cross-sectional area, so the bearing capacity of the steel reinforced concrete member can be greatly improved. When a general steel concrete column is damaged by an earthquake load, the column head and the column foot are damaged first, and at this time the bending moment in the middle area of the column has not yet reached the maximum resisting bending moment of the section, so only the column head and the column foot are damaged and consume energy. Other areas do not consume energy, have limited energy consumption capacity, and the mechanical properties of materials are not fully exerted.

Contents of the invention

Purpose of the invention: to provide a steel flange weakened recycled concrete anti-seismic energy-dissipating composite column to solve the above-mentioned problems existing in the prior art. The invention further provides a manufacturing method of the above-mentioned shaped steel flange weakened recycled concrete anti-seismic energy-dissipating composite column.

Technical solution: a steel flange weakened recycled concrete anti-seismic energy-dissipating composite column, including steel webs, longitudinal reinforcements arranged parallel to the steel webs, stirrups arranged along the longitudinal direction of the longitudinal reinforcements, and filling in between Concrete; the section steel web in the middle area of the composite column weakens the flange, the concrete is recycled aggregate concrete, and the replacement rate of waste concrete aggregate is 45-55%.

In a further embodiment, the recycled aggregate concrete comprises components in the following weight ratio: water: cement: sand: waste bricks: waste concrete blocks=1:(2～2.5):(2～2.5): (1～1.2): (4.8～5.5).

In a further embodiment, the recycled aggregate concrete includes components in the following weight ratio, water: cement: sand: waste bricks: waste concrete blocks = 1:2.27:2.27:1.04:5.21.

The method for making the above-mentioned steel flange weakened recycled concrete anti-seismic energy-dissipating composite column,

Step 1: According to the design requirements, the flange of the middle area of the steel column is weakened, the steel column is prefabricated, and the site is hoisted;

Step 2: Set the longitudinal reinforcement and tie the stirrup,

Step 3: Support formwork of steel concrete column formwork, pour concrete and vibrate.

Beneficial effects: First, the weakened section steel flange in the middle of the column can give full play to the performance of the column, and has better rigidity and ductility under the action of earthquake load, which improves the energy dissipation capacity of the column components and the safety of the structure; secondly, the middle of the column The weakening of the regional section steel flange effectively improves the concrete pouring density of the column, which helps to improve the construction quality; finally, in a further embodiment, it also has the following advantages: the section steel can be prefabricated in the factory in advance and hoisted on site, improving the construction efficiency. Save construction time; steel columns can be used as supporting components to bear the upper construction load, reducing the use of scaffolding; save steel and give full play to the performance of steel; the use of waste concrete coarse aggregate in recycled concrete can recycle construction waste, turn waste into treasure, save resources and protect the environment.

Description of drawings

Fig. 1 is a structural schematic diagram of an anti-seismic energy-dissipating composite column member weakened by a steel flange of the present invention.

Fig. 2 is a front view of the anti-seismic energy-dissipating composite column member weakened by the steel flange of the present invention.

Fig. 3 is a side view of the anti-seismic energy-dissipating composite column member weakened by the steel flange of the present invention.

detailed description

The main content of the present invention will be described in detail with reference to FIG. 1 to FIG. 3 . Specifically as shown in Figure 1 and Figure 2, the steel flange weakened recycled concrete anti-seismic energy-dissipating composite column of this embodiment includes a steel web 2, a longitudinal bar 3 arranged parallel to the steel web, and a longitudinal bar along the length direction of the bar. The stirrups 4 are set and the concrete filled therein; the steel web 1 located in the middle area of the composite column weakens the flange, the concrete is recycled aggregate concrete, and the replacement rate of waste concrete aggregate is 45-55%. In the present application, the substitution rate refers to the volume substitution rate.

It can be seen from Figure 1, Figure 2 or Figure 3 that the middle area of the steel web weakens the flange, so when it is damaged by force, the middle area bends and consumes energy, so that the performance of the steel web can be fully utilized. At the same time, the weakening of the steel flange in the middle area can effectively improve the concrete pouring density, thereby improving the construction quality.

In a further embodiment, the applicant has optimized the ratio of recycled aggregate concrete, and the more preferred ratio range is water: cement: sand: waste bricks: waste concrete blocks = 1: (2 ~ 2.5): ( 2～2.5):(1～1.2):(4.8～5.5).

Take concrete with a strength grade of C35 and a replacement rate of recycled aggregate of 50% as an example:

The weight ratio of each component in Example 1 is water: cement: sand: waste bricks: waste concrete blocks = 1:2.27:2.27:1.04:5.21. The standard method is used for detection, and the experimental data are as follows: the slump is 180, the workability is excellent, the 7-day compressive strength is 28.5MPa, and the 28-day compressive strength is 43.5MPa.

The specific process of embodiment 1 is as follows: the present invention carries out mix ratio calculation according to the following formula according to C35 grade concrete

According to the above formula to calculate α = 1, the apparent density of cement ρ _c = 3.1g/cm ³ , the density of water ρ _w = 1g/cm ³ , due to the apparent density of sand, waste bricks and waste concrete blocks Both are unknown, and its density needs to be measured and calculated by the drainage displacement method.

1. Determine the preparation strength f _cu,0

f _cu.0 =f _cu,k +1.645σ

When the strength grade of concrete is C35, σ=5.0MPa, then

f _cu,0 ＝48.2MPa

2. Preliminary determination of the water-cement ratio W:C

Since the 28d measured strength f _ce of the cement used in this experiment is unknown, it is expected that the measured 28d strength of the cement can reach 48.0MPa. Coarse aggregate is gravel, A=0.46, B=0.07

3. Preliminary estimate of unit water consumption

The maximum particle size is 40mm. Because the waste concrete block is subjected to a large external force during the crushing process, and the waste concrete block will produce a large number of cracks during the firing process, the water absorption rate and water absorption rate of the recycled aggregate are much higher than that of the natural aggregate. It is generally believed that the water absorption rate of recycled coarse aggregate is about 5% higher than that of natural aggregate. Therefore, it needs to be adjusted on the basis of the initially set water consumption.

When the maximum particle size is 40mm, m _W0 = 175kg/m ³ , after adjustment, m _W = 184kg/m ³

4. Calculate the amount of cement

5. Preliminary selection of sand rate β _S

(1) The maximum particle size of crushed stone used in concrete is 30mm, the water-cement ratio is 0.44, and the linear look-up table β _S =33.2%

(2) The maximum particle size of crushed stone used in concrete is 40mm, the water-cement ratio is 0.44, and the linear look-up table β _S =30.7%

6. Calculate the amount of sand and equivalent stone m _S , m _G

Simultaneously combine the above two formulas to solve the required m _S , m _G

7. Determine the amount of waste bricks and waste gas concrete blocks that need to be replaced;

This experiment refers to the volume replacement rate (the expected replacement rate is 20% for discarded clay bricks and 80% for discarded concrete blocks). The density ρ _RB of discarded brick blocks and the density ρ _RC of discarded concrete blocks are calculated by the drainage replacement method. Find the mass of the waste brick and waste concrete block blocks required: In the formula, m _RB , ρ _RB are the mass and density of waste bricks, n is the volume replacement rate of waste bricks, m is the replacement rate of waste concrete blocks, m+n=1, m _RC , ρ _RC are respectively Mass and density of waste concrete blocks.

According to the above calculation, the concrete mix ratio is: m _W : m _C : m _S : m _RB : m _RC = 1:2.27:2.77:1.04:5.21.

The specific calculation process of Embodiments 2 to 5 refers to Embodiment 1, adjusts relevant parameters, and obtains the ratio as follows:

The weight ratio of the components in Example 2 is water: cement: sand: waste bricks: waste concrete blocks = 1:2.11::2.48:1.15:5.25. The standard method is used for detection, and the experimental data are as follows: slump is 160, excellent workability, 7-day compressive strength is 22.5MPa, and 28-day compressive strength is 45MPa.

The weight ratio of the components in Example 3 is water: cement: sand: waste bricks: waste concrete blocks = 1:2.45:2.18:1.18:1.89. The standard method is used for detection, and the experimental data are as follows: the slump is 175, the workability is good, the 7-day compressive strength is 24.5MPa, and the 28-day compressive strength is 47.5MPa.

The weight ratio of the components in Example 4 is water: cement: sand: waste bricks: waste concrete blocks = 1:2.36:2.39:1.09:5.05. The standard method is used to test, the experimental data is as follows: slump 155, excellent workability, 7-day compressive strength 20.5MPa, 28-day compressive strength 48.5MPa.

The weight ratio of each component in Example 5 is water: cement: sand: waste bricks: waste concrete blocks = 1:2.40:2.06:1.12:5.15. The standard method is used for detection, and the experimental data are as follows: the slump is 185, the workability is good, the 7-day compressive strength is 21.5MPa, and the 28-day compressive strength is 46.5MPa.

The replacement rate of the control group is 0, and the 28d strength is about 48MPa. The strength of this implementation is basically the same, and the performance is better than the existing recycled aggregate concrete formula.

Example 6-8

Other processes refer to embodiment 1, in this group of embodiments,

The processing process of waste bricks is further as follows:

Remove impurities such as glass, plastic and steel bars in recycled aggregates (waste bricks and waste concrete blocks), and crush them with a jaw crusher; use 50mm aperture to sieve, and continue to crush the residue in the sieve, and the residue at the bottom of the sieve Sieve with a 20mm aperture, keep the residue in the sieve, and discard the residue at the bottom of the sieve; rinse the recycled aggregate with water and dry it in the air.

After calculating the ratio of water, cement, sand, gravel and discarded bricks, add recycled aggregate modified materials.

Recycled aggregate modified materials include: water reducing agent, reinforcing agent and expansion agent. The dosage of the water reducing agent is 0.1-0.5wt% of the total batching, the dosage of the reinforcing agent is 3-5wt% of the total batching, and the expansion agent is 1-3wt% of the total batching.

The structural formula of the water reducer is as follows:

Among them, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are all selected from H or CH ₃ , n is 35-55, m is 25-45, a, b, c and d are positive integers, M is one Valence cations.

The reinforcing agent is silica fume, and the expansion agent is sulphoaluminate.

The preparation method of above-mentioned novel polycarboxylate water reducer, the steps are as follows:

Step 1: Prepare or purchase the macromer, and weigh the raw materials according to the predetermined ratio;

Step 2: Add alkyl polyether, acrylic acid monomer, polymerization inhibitor, catalyst and water coordinating agent to the reaction kettle and raise the temperature to 160°C, carry out esterification reaction for 5 hours under reflux, and obtain an intermediate product; the catalyst is selected from sulfuric acid, One or more of toluenesulfonic acid, solid acid ZrO ₂ , said polymerization inhibitor is selected from one or more of hydroxyanisole, hydroquinone, sulfurized diphenylamine, and said water coordinating agent is selected from One or both of ethyl acetate and isoamyl alcohol.

Step 3: Separate the intermediate product and heat it to 90°C for dissolution, and add other monomers and initiator solutions dropwise at the same time. The dropping time is 1.2 hours. After the dropwise addition, keep warm for 6 hours. After the reaction is completed, cool to 40°C Adjust the pH to 7 with sodium hydroxide solution to obtain the target product.

In embodiment 6, the proportion of water, cement, sand, gravel and waste bricks is the same as that of embodiment 1, adding 0.26wt% water reducer, 4.1wt% reinforcing agent and 1.9wt% expansion agent.

In embodiment 7, the proportion of water, cement, sand, gravel and waste bricks is the same as that of embodiment 2, adding 0.11wt% water reducer, 3.2wt% reinforcing agent, and 2.7wt% expansion agent .

In Example 8, the ratio of cement, sand, gravel and waste bricks is the same as that of Example 3, and 0.45wt% of water reducer, 4.9wt% of reinforcing agent, and 1.2wt% of expansion agent are added.

Using the same test method, the obtained 28d strength data are as follows: 48.8, 53.4 and 55.5.

In this group of embodiments, cleaning the recycled aggregate can remove the dust attached to it, and at the same time, silica fume can reduce the void ratio and void size inside the concrete, improve the cement paste structure on the aggregate interface, and the pozzolanic effect of silica fume And particle filling effect, good adhesion between slurry and aggregate. High-efficiency water reducer can not only reduce the water-cement ratio, but more importantly, make the cement in the mixture more dispersed, so that the porosity and pore distribution after hardening can be further improved. The expansion agent can counteract the shrinkage produced by the recycled aggregate, and solve the problem of large shrinkage of the recycled aggregate concrete in the prior art.

Finally, this embodiment also provides a method for making the above-mentioned steel flange weakened recycled concrete anti-seismic energy-dissipating composite column, including the following steps:

Step 1: Weaken the flange in the middle area of the column-shaped steel according to the design requirements, determine the section size, steel size, position and length of the removed flange, length, longitudinal steel reinforcement ratio, stirrup reinforcement ratio and recycled concrete strength grade, in The steel column is prefabricated in the factory, and the steel column is hoisted on site;

Step 2: Set the longitudinal reinforcement and bind the stirrup;

Step 3: Support formwork of steel concrete column formwork, pour concrete and vibrate.

When pouring concrete, it is difficult to unload the concrete for the parts where the steel flange is not weakened and the parts where the steel bars are staggered densely, so special care must be taken when pouring, and the vibrating should be careful and in place to ensure the compactness of the concrete and the construction quality.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be carried out to the technical solutions of the present invention. These equivalent transformations All belong to the protection scope of the present invention. In addition, it should be noted that the various specific technical features described in the above specific implementation manners may be combined in any suitable manner if there is no contradiction.

Claims (1)

1. The method for making the steel flange weakened recycled concrete anti-seismic energy-dissipating composite column is characterized in that, the described steel flange weakens the recycled concrete anti-seismic energy-dissipating composite column and comprises a steel web (2), which is arranged in parallel with the steel web The longitudinal reinforcement (3), the stirrups (4) arranged along the length direction of the longitudinal reinforcement and the concrete filled therein; the section steel web weakening flange located in the middle area of the composite column, The concrete is recycled aggregate concrete, the replacement rate of waste concrete aggregate is 45-55%, and the replacement rate refers to the volume replacement rate; the recycled aggregate concrete includes the following components in weight ratio, water: cement: sand: Abandoned bricks: Abandoned concrete blocks = 1:2.45:2.18:1.18:1.89; The treatment process of waste bricks is as follows: remove the glass, plastic and steel bars in the recycled aggregate, and crush them with a jaw crusher; use 50mm aperture to sieve, continue to crush the residue in the sieve, and carry out 20mm aperture for the residue at the bottom of the sieve Sieve, keep the residue in the sieve, and discard the residue at the bottom of the sieve; rinse the recycled aggregate with water, and dry it; After calculating the ratio of water, cement, sand, gravel and waste bricks, add recycled aggregate modified materials; The recycled aggregate modified materials include: water reducing agent, reinforcing agent and expansion agent; the consumption of water reducing agent is 0.45wt% of the total amount of ingredients, the amount of reinforcing agent is 4.9wt% of the total amount of ingredients, and the amount of expansion agent is 1.2wt% of the total amount of ingredients; The structural formula of the water reducer is as follows: Among them, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are all selected from H or CH ₃ , n is 35-55, m is 25-45, a, b, c and d are positive integers, M is one Valence cation; The reinforcing agent is silica fume, and the expansion agent is sulfoaluminate; The preparation method of the above-mentioned water reducing agent, the steps are as follows: Step 1: Prepare or purchase the macromer, and weigh the raw materials according to the predetermined ratio; Step 2: Add alkyl polyether, acrylic acid monomer, polymerization inhibitor, catalyst and water coordinating agent to the reaction kettle and raise the temperature to 160°C, carry out esterification reaction for 5 hours under reflux, and obtain an intermediate product; the catalyst is selected from sulfuric acid, One or more of toluenesulfonic acid and solid acid ZrO ₂ , the polymerization inhibitor is selected from one or more of hydroxyanisole, hydroquinone, diphenylamine vulcanization, and the water coordinating agent is selected from One or both of ethyl acetate and isoamyl alcohol; Step 3: Separate the intermediate product and heat it to 90°C for dissolution, and add other monomers and initiator solutions dropwise at the same time. The dropping time is 1.2 hours. After the dropwise addition, keep warm for 6 hours. After the reaction is completed, cool to 40°C Adjust the pH to 7 with sodium hydroxide solution to obtain the target product; The method for making a steel flange weakened recycled concrete anti-seismic energy-dissipating composite column includes the following steps: Step 1: According to the design requirements, the flange of the middle area of the steel column is weakened, the steel column is prefabricated, and the site is hoisted; Step 2: Set the longitudinal reinforcement and tie the stirrup, Step 3: Support formwork of steel concrete column formwork, pour concrete and vibrate.