CN204882267U - Testing arrangement that twists reverse who creeps is cuted to concrete - Google Patents

Abstract

The utility model discloses a testing arrangement that twists reverse who creeps is cuted to concrete, including the concrete base, the cylindrical concrete round bar of vertical setting is pour at concrete base center, installs the support steelframe on the concrete base, at present adopt the beam type loading to come to test the shear effect of concrete usually, the utility model provides a be used for testing the method of creeping of shearing through exerting the concrete cylinder to reverse. Testing arrangement exerts two pairs of concentrated forces through the steel tendon and is used in the bottom and solidifies at subaerial cylinder concrete peripherally, forms moment of torsion shear effect. Steel tendon one end is suspended in midair has the steel bracket that loads the concrete piece to form the load to through concreteing the device that turns to that forms braced system and steel tendon at subaerial support steelframe in the bottom, and come the test to be located the displacement of the spacer bar on the concrete cylinder and then the shearing of calculating the concrete is crept through the displacement meter.

Description

A Torsion Test Device for Concrete Shear Creep

【Technical field】

The utility model belongs to the technical field of concrete creep tests and relates to a torsion test device for concrete shear creep.

【Background technique】

At present, the creep coefficient in concrete creep theory is usually obtained based on the experimental research under uniaxial stress conditions. Some previous creep models based on extensive research and experiments such as B3 model, CEB-FIP model, ACI-209R model Various factors such as concrete strength, cement type, and relative humidity have been considered comprehensively, but the stress conditions of the test are all axial compressive stress states. The creep part of the newly proposed B4 model is consistent with the B3 model and still uses axial stress. State, just perfecting the shrinkage considerations. However, there are few researches on the creep test of concrete under shear. It is only assumed that the creep deformation under various internal forces can be obtained approximately by using a unified creep coefficient, that is, it is assumed that the creep coefficient under the action of shear is the same as that under the action of axial force or bending. However, the study found that the creep displacement generated under shear cannot be ignored, and a separate test for concrete shear creep is required.

【Content of utility model】

The purpose of this utility model is to overcome the above-mentioned shortcomings of the prior art, and provide a torsion test device for concrete shear creep, which can quantify the effect of concrete shear creep, and solve the problems caused by shear creep in current projects. The mechanism of the long-term deformation provides a reference for the prediction and calculation of the deformation of concrete structures.

In order to achieve the above object, the utility model adopts the following technical solutions to achieve:

A torsion test device for concrete shear and creep, comprising a concrete base, a vertically arranged cylindrical concrete round bar is poured in the center of the concrete base, a supporting steel frame is installed on the concrete base; a force-transmitting steel bar is arranged on the upper part of the concrete round bar, The middle part of the load bracket is open, and it is set on the concrete round rod from top to bottom, and is hoisted on the supporting steel frame by steel strands; one end of the steel strand is connected to the load bracket, and the other end is connected to the force-transmitting steel bar.

The further improvement of the utility model is:

The supporting steel frame is fixed on the concrete base by bolts.

The top of the supporting steel frame is provided with a turning steel channel, and the steel strand is connected to the force-transmitting steel bar after passing through the turning steel channel.

The force-transmitting reinforcing bars are two crossing reinforcing bars arranged in the concrete round rod, and the two ends of the two reinforcing bars protrude from the side of the concrete round rod respectively.

A positioning reinforcement is arranged below the force-transmitting reinforcement, and the displacement change of the positioning reinforcement is measured by a displacement meter to calculate the shear creep.

Compared with the prior art, the utility model has the following beneficial effects:

The utility model transmits the load generated by the concrete block loaded on the steel bracket through the steel wire bundle and the supporting steel frame whose bottom end is consolidated on the concrete base by bolts, and forms a concrete column on the concrete base at the bottom end For the torsional shear action, the shear creep is calculated by collecting the deformation caused by torsion by testing the displacement of the positioning steel bar on the concrete cylinder with a dial gauge. Compared with the traditional beam shear test, this test device only has torsional shear action, without the influence of other factors such as bending moment, and can accurately test the shear creep of concrete.

【Description of drawings】

Fig. 1 is the structural representation of the utility model concrete round rod and concrete base;

Fig. 2 is the structural representation of the utility model supporting steel frame;

Fig. 3 is the structural representation of the utility model load bracket;

Fig. 4 is a schematic diagram of the positions of the force-transmitting reinforcement and the positioning reinforcement of the utility model;

Fig. 5 is a schematic diagram of the overall structure of the utility model.

Among them: 1 is the concrete base; 2 is the concrete round rod; 3 is the supporting steel frame; 4 is the bolt; 5 is the load bracket; 6 is the force transmission steel bar; 7 is the positioning steel bar; 8 is the steel strand; groove.

【Detailed ways】

Below in conjunction with accompanying drawing, the utility model is described in further detail:

Referring to Fig. 1 to Fig. 5, the torsion test device for concrete shear and creep of the utility model comprises a concrete base 1, and a vertical cylindrical concrete rod 2 is poured in the center of the concrete base 1, and a supporting steel rod 2 is installed on the concrete base 1. frame 3; the upper part of the concrete round rod 2 is provided with a force-transmitting steel bar 6, and the middle part of the load bracket 5 is open, and is sleeved on the concrete round rod 2 from top to bottom, and is hoisted on the supporting steel frame 3 through a steel strand 8; One end of the steel strand is connected to the load bracket 5, and the other end is connected to the force-transmitting steel bar 6. The supporting steel frame 3 is fixed on the concrete base 1 by bolts 4 . The top of the supporting steel frame 3 is provided with a turning steel channel 9, and the steel strand 8 is connected to the force transmission steel bar 6 after passing through the turning steel channel 9. The force-transmitting steel bars 6 are two steel bars crossed and arranged in the concrete round rod 2 , and the two ends of the two steel bars protrude from the sides of the concrete round rod 2 respectively. A positioning steel bar 7 is arranged below the force transmission steel bar 6, and the displacement change of the positioning steel bar 7 is measured by a displacement meter to calculate the shear creep.

The shear creep test device involved in the utility model consists of a concrete cylinder whose lower end is consolidated on the concrete base, a supporting steel frame whose lower end is consolidated on the concrete base by bolts, a steel bracket, a steel wire bundle, a dial gauge, Concrete loaded block composition. The shear creep member is a cylindrical concrete rod 2 as shown in Fig. 1, which is consolidated on the concrete base 1 during pouring and fabrication. The supporting steel frame 3 in Fig. 2 is consolidated with the concrete base 1 through high-strength bolts 4. The load bracket 5 used to load the load block is suspended on the supporting steel frame 3 through the steel strand 8 connected to the force-transmitting steel bar 6 in Fig. The torque on the test member forms a pure shear action on the cylindrical concrete rod, and the displacement change of the positioning steel bar 7 in Figure 4 is measured by the displacement meter to calculate the shear creep.

The purpose of the utility model is to calculate the shear creep calculation mode through long-term observation of the shear strain of the straight concrete cylinder in the shear test under the pure shear action, and provide a theoretical reference for bridge design considering the shear action. The specific test method is as follows:

1. Pour the concrete member shown in Figure 1, the height of the equivalent round rod is L, and the section radius is r.

2. Assemble the supporting steel frame in Figure 2 and the load bracket in Figure 3 in sequence.

3. Install a displacement meter to measure the displacement of the positioning steel bar.

4. To apply the load, place the concrete load block on the load bracket.

5. Read the initial displacement l(t ₀ ), then the initial shear strain is

6. The displacement l(t,t ₀ ) of the positioning reinforcement at time t is obtained through the long-term data collection of the header, and the shear strain of the member at time t is $\mathrm{\γ}(t,t_0)=\frac{r\×arcta\mathrm{no}\frac{l(t,t_0)}{r}}{L}.$

7. The shear creep coefficient is described by φ _sc (t,t ₀ ), then

The above content is only to illustrate the technical idea of the utility model, and cannot limit the protection scope of the utility model. Any changes made on the basis of the technical solution according to the technical idea proposed by the utility model all fall into the scope of the utility model. within the scope of protection of the claims.

Claims (5)

1. the concrete shearing torsion proving installation of creeping, it is characterized in that, comprise concrete bed (1), the cylindrical concrete round bar (2) vertically arranged is built at concrete bed (1) center, concrete bed (1) is provided with supporting steel frame (3); Concrete round bar (2) top is provided with power transmission reinforcing bar (6), load bracket (5) intermediate openings, and be set on concrete round bar (2), and be lifted on supporting steel frame (3) by steel strand wires (8) from top to bottom; Steel strand wires one end is connected with load bracket (5), and the other end is connected on power transmission reinforcing bar (6).

2. the concrete shearing according to claim 1 torsion proving installation of creeping, it is characterized in that, described supporting steel frame (3) is fixed on concrete bed (1) by bolt (4).

3. the concrete shearing according to claim 1 torsion proving installation of creeping, it is characterized in that, the top of described supporting steel frame (3) is provided with and turns to steel tank (9), and steel strand wires (8) are connected on power transmission reinforcing bar (6) after turning to steel tank (9).

4. the concrete shearing according to claim 1 torsion proving installation of creeping, it is characterized in that, described power transmission reinforcing bar (6) is the reinforcing bar that two right-angled intersections are arranged in concrete round bar (2), and the side of concrete round bar (2) is stretched out at the two ends of two reinforcing bars respectively.

5. the concrete shearing according to claim 4 torsion proving installation of creeping, it is characterized in that, the below of described power transmission reinforcing bar (6) is provided with spacer bar (7), by change in displacement and then the reckoning shear creep of displacement meter measurement and positioning reinforcing bar (7).