CN203849110U - Eccentric compression column non-unloading strengthening testing device - Google Patents

Abstract

The utility model discloses a non-unloading reinforcement test device for an eccentric compression column, which comprises a reaction force rigid frame, a movable rigid beam capable of moving up and down, a load applying device, two force sensors and a strain gauge connected with the two force sensors. The reaction rigid frame is composed of two rigid frame columns and a fixed beam. The test column to be tested is installed between the fixed beam and the movable rigid beam, and the movable rigid beam is set between the two rigid frame columns; the test column and its upper end One-way knife hinges and pressure distribution plates are set between the fixed beams and between the test column and the movable rigid beam at the lower end, and the pressure distribution plates are all in contact with the end faces of the test column; the test device also includes a The tight hoops prepared in pairs at the end of the column, the tight hoops are composed of two semicircular steel plates and bolts. The utility model has the advantages of good controllability, simple structure and convenient operation, and can avoid local concrete at the column end from being crushed before the whole test piece is destroyed, thereby causing test failure.

Description

Non-unloading reinforcement test device for eccentric compression columns

technical field

The utility model belongs to a test device, in particular to a non-unloading reinforcement test device for an eccentric compression column.

Background technique

If the compression member that is being put into use needs to be reinforced, it should be unloaded first so that the effect of the reinforcement layer can be fully exerted, but it is difficult to do this in actual engineering, and it can only be partially unloaded or not unloaded at all, that is, The original component has been subjected to load before reinforcement, which is called the first-stage load. After reinforcement, only when the external load continues to increase, which is called the second-stage load, and the deformation of the component continues to increase, the reinforcement layer will Assist the original member to bear the new external load, which makes the stress and strain of the original member ahead of the reinforcement layer.

At present, the test of non-unloading reinforcement of compression members is usually carried out on the hydraulic long column testing machine, that is, when the column is stabilized in the "first-stage load" condition, the column is made on the testing machine. The reinforcement layer is maintained to the corresponding age , and then complete the "second stage loading" until the reinforcement column is destroyed. The disadvantages of this method are obvious, including too much machine time due to the long maintenance period of the reinforcement layer, large loss of testing machine due to long-term overheating, and poor pressure stabilization effect under high load of the hydraulic machine, resulting in "the first stage of loading""The corresponding stress level index β distortion becomes smaller (definition β=N ₀ /N, N ₀ is the actual load value after the "first-stage load" is stabilized, N is the ultimate failure load of the original column), or in order to maintain the stress The repeated pressure-replenishment operations made by the horizontal index β may completely eliminate the newly established bond between the cementitious material in the reinforcement layer and the original column concrete. In addition, it is very inconvenient to carry out reinforcement construction operations on the long column testing machine. The experimental research on the mechanical performance of reinforced concrete eccentric compression columns is an important aspect of the non-unloading reinforcement test of compression members, and it is of great significance to carry out the experimental research on the non-unloading reinforcement of large-scale eccentric compression columns that conforms to the actual engineering situation.

At present, when carrying out the bias test of reinforced concrete columns or concrete-filled steel tube columns, due to the unevenness of the loading end or uneven local loading, it often happens that the local concrete at the end of the column is crushed before the specimen reaches the ultimate bearing capacity. The phenomenon that leads to the failure of the whole experiment makes the experiment process to be abandoned halfway, and the experiment result is not ideal, thus causing a waste of scientific research funds. In fact, in the process of building structure testing, it is very difficult or even impossible to ensure that the end of the specimen is absolutely flat and the loading is absolutely uniform. Therefore, it is an urgent technical problem to be solved in the building structure test to find a method to ensure that the column end does not fail before the integral member.

Contents of the invention

The purpose of this utility model is to overcome the problems existing in the prior art, such as poor voltage stabilization effect, large machine loss, inconvenient use and failure of the whole test due to local concrete crushing at the end of the column before the specimen reaches the ultimate bearing capacity, and provides a A non-unloading reinforcement test device for eccentric compression columns. The device not only has a simple structure, is safe and reliable, but also has a good pressure stabilization effect under high loads, ensuring that the loaded column end does not fail before the specimen reaches the ultimate bearing capacity.

Through a large number of domestic and foreign literature readings and on-site investigations, it was found that the problems of the test device and test method for simulating the "two-stage loading" of full-scale reinforced columns have not been well resolved, so that various methods have been adopted at home and abroad to strengthen steel bars in recent years. In the experimental research of concrete compression members, it is a one-time load reinforcement study that does not conform to the actual engineering situation, that is, the original column of the experimental column completes the production of the reinforcement layer without bearing, and then puts it in the pressure testing machine Conduct a destructive test. As for the actual engineering problem that the strain and stress of the solid layer lag behind the original column, a reduction factor is uniformly used for consideration, but the actual situation is often due to the difference in the stress level index β under the "first stage loading", It varies with the type of column member, the type of reinforcement layer material, etc. It can be seen that this reduction factor method is very rough, which naturally leads to the unreliability and unreliability of the reinforcement design.

For realizing the purpose of this utility model, the technical scheme that adopts is as follows:

The non-unloading reinforcement test device for eccentric compression columns includes a reaction force frame, a movable rigid beam that can move up and down, a load application device, two force sensors and strain gauges connected to the two force sensors. The reaction force frame consists of two Composed of a rigid frame column and a fixed beam, the test column to be tested is installed between the fixed beam and the movable rigid beam, and its special feature is that the movable rigid beam is set between two rigid frame columns; One-way knife hinges and pressure distribution plates are arranged between the fixed beams at the upper end and between the test column and the movable rigid beam at the lower end, and the pressure distribution plates are all in contact with the end faces of the test columns; A pair of braces at the column ends of the column, said braces consisting of two semi-circular steel plates and bolts.

Further, the load applying device includes two screw jacks and a hydraulic jack, and the hydraulic jack is arranged between the two screw jacks.

Further, the movable rigid beam is a steel structure box-section beam, the aspect ratio of the movable rigid beam is 4, dense stiffening ribs are arranged inside the movable rigid beam, and four The small wheel; the inner surface of the column of the rigid frame is provided with a channel that allows the small wheel to roll up and down freely.

Further, the screw jack is a screw mechanical jack with a rated tonnage of 1000kN; the hydraulic jack is a hydraulic jack with a rated tonnage of 5000kN, and the hydraulic jack is connected to a high-pressure electric oil pump equipped with a high-precision hydraulic gauge.

Further, the test device also includes a safety steel rope for protecting the test column.

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

1. The load application capacity and measurement range of the test device can meet the test requirements for the maximum pressure bearing capacity of the full-scale test column after reinforcement, which is consistent with the actual situation of the project.

2. The loading and stabilizing effect of the test device can satisfy the requirement that the newly made reinforcement layer that is not directly compressed and firmly bonded to the surface of the original column is always in a zero stress state during the load-holding period.

3. The test device can accurately measure the actual load size and deformation value of its components at each moment and under each load level, meeting the measurement accuracy requirements.

4. The test device meets the safety requirements.

5. The test device has good controllability, simple structure and easy operation.

6. In the axial compression or bias test, the use of this device can avoid the local concrete at the column end from being crushed before the overall failure of the specimen due to the unevenness of the loading plate at the loading end or the uneven loading of the local area, resulting in the failure of the test.

7. Conducive to saving research funds and time.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Fig. 2 is a schematic structural view of the tightening member in Fig. 1;

Among them, 1. fixed beam; 2-one-way knife hinge; 3. pressure distribution plate; 4. test column; 5. tight hoop; 5-1. semicircular steel plate; Rigid beam; 7. Force sensor; 8. Hydraulic jack; 9. Screw jack; 10. Rigid frame column; 11-safety steel rope.

Detailed ways

In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not intended to limit the utility model.

Figure 1 shows the structure of the non-unloading reinforcement test device for eccentric compression columns provided by the utility model. For ease of description, only the parts relevant to the present utility model are shown.

The non-unloading reinforcement test device of the eccentric compression column of the present utility model comprises: a reaction force rigid frame, a movable rigid beam 6 that can move up and down, a load applying device, two force sensors 7 and a strain gauge connected to the two force sensors, The reaction rigid frame is composed of two rigid frame columns 10 and a fixed beam 1. The test column to be tested is installed between the fixed beam 1 and the movable rigid beam 6, and the movable rigid beam 6 is arranged between the two rigid frame columns 10. Between the test column 4 and the fixed beam 1 at the upper end and between the test column 4 and the movable rigid beam 6 at the lower end, a one-way knife hinge 2 and a pressure distribution plate 3 are arranged, and the pressure distribution plate is connected to the end surface of the test column. Contact; the test device also includes tight hoops 5 installed in pairs at the column ends of the test column, and the tight hoops are composed of two semicircular steel plates 5-1 and bolts 5-2.

As an optimized solution of the embodiment of the present invention, the load applying device includes two screw jacks 9 and one hydraulic jack 8 , and the hydraulic jack 8 is arranged between the two screw jacks 9 .

As an optimization scheme of the embodiment of the present utility model, the movable rigid beam 6 is a box-shaped beam of steel structure, the aspect ratio of the movable rigid beam 6 is 4, and the movable rigid beam 6 is provided with dense stiffening ribs, Four small wheels are respectively arranged at both ends of the movable rigid crossbeam 6; the inner surface of the rigid frame column 10 is provided with a channel that allows the small wheels to roll up and down freely.

As an optimization scheme of the utility model embodiment, the screw jack 9 is a screw type mechanical jack with a rated tonnage of 1000kN; High pressure electric oil pump connection.

As an optimized solution of the embodiment of the present utility model, the test device also includes a safety steel rope 11 for protecting the test column.

The application principle of the present utility model will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1 and Figure 2, the non-unloading reinforcement test device for eccentrically compressed columns in the embodiment of the present invention includes: a reaction force rigid frame, a movable rigid beam 6 that can move up and down, a load applying device, and two force sensors 7 and the strain gauge connected with the two force sensors, the reaction force rigid frame is composed of two rigid frame columns 10 and a fixed beam 1, the test column to be tested is installed between the fixed beam 1 and the movable rigid beam 6, and the movable rigid frame The beam 6 is set between two rigid frame columns 10; the one-way knife hinge 2 and the pressure distribution plate 3 are set between the test column 4 and the fixed beam 1 at the upper end and between the test column 4 and the movable rigid beam 6 at the lower end , the pressure distribution plates are all in contact with the end face of the test column; the test device also includes a pair of clamps 5 installed at the end of the test column, see Figure 2, the clamp consists of two semicircular steel plates 5-1 and bolt 5-2, the two ends of the two semicircular steel plates 5-1 are fastened and connected by bolts 5-2 respectively. At the same time, fit fastening bolts on the small holes.

The load applying device includes two screw jacks 9 and a hydraulic jack 8 , and the hydraulic jack 8 is arranged between the two screw jacks 9 . Screw jack 9 is a screw-type mechanical jack with a rated tonnage of 1000kN; hydraulic jack 8 is a hydraulic jack with a rated tonnage of 5000kN, and the hydraulic jack is connected to a high-pressure electric oil pump equipped with a high-precision hydraulic gauge.

The movable rigid beam 6 is a box-section beam of steel structure. The aspect ratio of the movable rigid beam 6 is 4. The movable rigid beam 6 is provided with dense stiffening ribs, and there are four movable rigid beams at each end. Small wheel; the inner surface of the rigid frame column 10 is provided with a channel that allows the small wheel to roll up and down freely.

The test device also includes a safety steel rope 11 for protecting the test column.

When making the experimental device of the utility model, it is fully considered that the large-tonnage long-column testing machine has the characteristics of convenient loading and testing and high precision, but the long-term voltage stabilization effect is poor, and the machine itself wears a lot. Reduce the life of the machine; the hydraulic jack has a large loading range near the top, and does not need to be manually shaken like a mechanical jack, but the long-term pressure stabilization effect is poor, and oil leakage occurs; a single mechanical jack is mostly manual operation, the maximum loading tonnage is too small to meet the range requirements of the full-scale column, but the long-term voltage stabilization effect is excellent. After comprehensively considering the respective advantages and disadvantages of the loading equipment, and considering the safety factors and the convenience and controllability of the operation, the non-unloading reinforcement test device for eccentric compression columns of the present utility model as shown in Figure 1 has been developed. All parts of the device work in harmony, which can well meet the requirements of range range, voltage stabilization effect, measurement accuracy, safety, controllability, and ease of operation. Through this device, the scientific test of the eccentrically compressed model column and the test detection of the actual engineering column member can be completed, and a large amount of valuable and reliable test data can be provided for research and analysis.

When the test device of the utility model is performing the non-unloading reinforcement test of the eccentric compression column, the vertical compression load is applied to the column through the one-way knife hinge at the upper and lower ends of the column, and the vertical load is distributed in the form of line load along the length of the knife hinge. It is a bias load with a certain eccentricity relative to the centroid axis of the column section.

Test method: According to the relevant provisions of the "Building Structure Test Regulations", the hydraulic jack of this test device and the high-pressure electric oil pump used in conjunction with it are calibrated on the precise long-column hydraulic testing machine, and the two screw-type mechanical jacks are placed opposite Calibrate the force sensor and the strain gauge used with it; place the 3 jacks, the up and down movable rigid beam, the upper and lower end knife hinges of the column, the pressure distribution plate, and the test column in place according to the position shown in Figure 1, and tighten the hoop parts and safety wires, and carry out geometric alignment of each part. The tightening hoop of the utility model achieves the purpose of improving the local compressive strength of the concrete at the end of the column by tightening the bolts on the hoop to make the semicircular steel plate generate local horizontal pressure on the surface of the column end. After the preparatory work such as positioning, centering, and calibration of each part is completed, it should be checked whether the safety steel rope is in a non-stressed state. By observing the strain changes on the strain gauges connected to the two force sensors, the two operators are instructed to shake and press the two screw jacks at the same time, so that they can push the movable beam symmetrically and evenly, thereby applying an axial load to the column. When the load value reaches When the design load value (the corresponding stress level index is β) of the "first-stage load", stop the rocking pressure. In the initial period under the load value of the first stage, the reinforced concrete column will undergo elastic compression deformation, so that the actual compressive stress ratio of the column will gradually be lower than β. Therefore, the change of strain on the strain gauge should be observed within the first week, and the pressure supplement operation should be performed appropriately if necessary. When the strain value no longer drops or there are only a few micro-strain changes, it means that the stable pressure level has been basically reached. This process takes advantage of the characteristics of the good voltage stabilization effect of the mechanical jack. The load value corresponding to the "first-stage load" generally does not exceed 60% of the ultimate failure load of the reinforced column. Although the manually operated mechanical jack has a relatively small rated tonnage, two 1000kN screw jacks are used side by side in the device. A mechanical jack will suffice. The test columns that have been stably subjected to the axial load of N ₀ and have completed the pretreatment of the reinforcement construction are reinforced, and cured or consolidated to the corresponding age. After the maintenance or consolidation of the corresponding age, after the strength of the reinforcement layer itself and the bonding strength of the joint surface with the original column meet the design requirements, start to use the high-pressure oil pump and the 5000kN hydraulic jack located at the lower part of the movable rigid beam, and pass Observe the readings of the hydraulic gauge to control the loading speed and load level, that is, to realize and complete the "second stage loading" test process of the reinforced column until the test column reaches the maximum bearing capacity and then fails. In the process of "loading in the second stage", the two mechanical jacks gradually quit working, and the hydraulic jacks gradually bear more and more or even all the compressive loads (so the column axial force under all levels of load should be applied by three jacks sum of the axial load). After the reinforced column reaches the maximum bearing capacity, the pointer of the oil pressure gauge starts to retreat, and when the load value returns to 80% of the maximum bearing capacity, the test is stopped, the hydraulic equipment is turned off and the oil is returned, and the test is over. Since most of the reinforced columns are ductile failures with obvious signs, the pointer of the oil pressure gauge retreats slowly. Because of the protection of the safety steel rope, the safety is well guaranteed.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present utility model shall be included in this utility model. within the scope of protection of utility models.

Claims (5)

1. the non-unloading reinforcement experiment of eccentric compression post device, comprise counter-force rigid frame, portable rigid beam moving up and down (6), load applying device, two power sensors (7) and the strainmeter being connected with two power sensors, counter-force rigid frame is comprised of two rigid frame columns (10) and fixed cross beam (1), testing column to be measured is installed between fixed cross beam (1) and portable rigid beam (6), it is characterized in that: described portable rigid beam (6) is arranged between two rigid frame columns (10); Unidirectional cutter hinge (2) and pressure distribution plate (3) are all set between the fixed cross beam (1) of testing column (4) and its upper end and between the portable rigid beam (6) of testing column (4) and its lower end, pressure distribution plate all with testing column styletable end contact; Described test unit also comprises the fastening piece (5) of the paired preparation in styletable place that is arranged on testing column, and described fastening piece consists of two semicircle steel plates (5-1) and bolt (5-2).

2. the non-unloading reinforcement experiment of eccentric compression post according to claim 1 device, it is characterized in that: described load applying device comprises two screw jacks (9) and a fluid pressure type lifting jack (8), and fluid pressure type lifting jack (8) is arranged between two screw jacks (9).

3. the non-unloading reinforcement experiment of eccentric compression post according to claim 1 device, it is characterized in that: described portable rigid beam (6) cuts section bar for steel construction box, the length breadth ratio of portable rigid beam (6) is 4, in portable rigid beam (6), be provided with the intensity floor of putting more energy into, portable rigid beam (6) two ends respectively arrange four steamboats; The medial surface setting of described rigid frame column (10) can make the conduit of the free scroll-up/down of steamboat.

4. the non-unloading reinforcement experiment of eccentric compression post according to claim 2 device, is characterized in that: described screw jack (9) for specified tonnage be 1000kN screw machine lifting jack; Described fluid pressure type lifting jack (8) for specified tonnage be 5000kN fluid pressure type lifting jack, fluid pressure type lifting jack is connected with the high-voltage electric oil pump that high-precision hydraulic table is housed.

5. the non-unloading reinforcement experiment of eccentric compression post according to claim 1 device, is characterized in that: described test unit also comprises the safe steel cable (11) for the protection of testing column.