CN104458401A - Continuous beam testing method - Google Patents

Abstract

The invention provides a continuous beam test method, the specific steps are as follows: from the beginning of loading to the critical concrete cracking, load according to each level of 5kN load; Each level of 10kN load is loaded; from the maximum crack width of the test beam exceeding 0.5mm to the final failure of the adjacent structure, each level of 5kN load is applied. The continuous beam test device involved in the present invention has a simple structure, can effectively test the continuous beam, and has accurate test results.

Description

A continuous beam test method

technical field

The invention relates to a continuous beam test method, which belongs to the technical field of machinery.

Background technique

In recent years, foreign scholars have carried out more relevant experimental research and theoretical analysis on the application of CFRP-PCPs composite bars in concrete structures, mainly using simply supported beams as the starting point. There are relatively few studies. In addition, there are fewer experimental data on the plastic internal force redistribution law of CFRP-PCPs composite reinforced concrete continuous beams, and the determination of its bending moment amplitude modulation value is still to be studied.

Contents of the invention

The invention provides a continuous beam test method, which can overcome the above-mentioned defects.

In order to solve the above technical problems, the present invention provides the following technical solutions: a continuous beam test method, including a load cell, a screw jack, an electronic displacement meter, a reaction force frame, and a hydraulic jack; after the test device is connected, before the formal test, the First, preload the test beam to check whether the test instruments are working normally and whether the test beam is placed stably and centered; the preload is 10% of the calculated cracking load, unload slowly after loading, and adjust each test according to the preload results Instrument; when formally loading, load in stages according to the calculated failure load value in advance, because the oil pump is used for loading, in order to better control the loading speed and obtain a relatively stable deformation value when observing the structure, the test is graded at 10kN per level Loading, collect all data after holding the load for 3 minutes after each level; the specific loading steps are as follows:

1. From the beginning of loading to the critical concrete cracking, load according to each level of 5kN load;

2. From the cracking of the concrete to the occurrence of cracks with a width of 0.5mm near each control section, load according to the load of 10kN per level;

3. From the maximum crack width of the test beam exceeding 0.5mm to the final failure of the adjacent structure, the load shall be loaded at each level of 5kN.

This continuous beam test method that the present invention relates to, in order to study the plastic performance of CFRP-PCPs composite reinforced concrete continuous beam, prepared 6 composite reinforced concrete two-span continuous beam specimens altogether, through experimental research, mainly completed the following relevant Project work:

(1) The static load test of six CFRP-PCPs composite reinforced concrete two-span continuous beams was completed.

(2) The crack form and distribution law, load-deflection curve, etc. of the test beam near the control sections at the mid-span and mid-support of the two spans were observed and analyzed.

(3) The mechanical performance of the test beam at each stage, the change process of the support reaction force and the final failure form were observed and analyzed.

(4) The strain values of ordinary steel bars, CFRP-PCPs composite bars and concrete in the test beams were observed and recorded throughout the process.

(5) The phenomenon of plastic internal force redistribution of continuous beams was observed and analyzed.

The continuous beam test device involved in the present invention has a simple structure, can effectively test the continuous beam, and has accurate test results.

Description of drawings

Fig. 1 is a kind of continuous beam test device structural representation of the present invention;

1 Load sensor I; 2 Load sensor II; 3 Screw jack; 4 Electronic displacement gauge; 5 Load sensor III; 6 Reaction frame; 7 Hydraulic jack.

Detailed ways

As shown in Figure 1, a continuous beam test method, including load sensor I1, load sensor II2, load sensor III5, screw jack, electronic displacement gauge, reaction force frame, hydraulic jack; after the test device is connected, before the formal test , the test beam should be preloaded first to check whether the test instruments are working normally and whether the test beam is placed stably and centered; the preload is 10% of the calculated cracking load, unload slowly after loading, and adjust according to the preloading results Each test instrument; when formally loaded, it is loaded in stages according to the calculated failure load value in advance. Because the oil pump is used for loading, in order to better control the loading speed and obtain relatively stable deformation values when observing the structure, the test is carried out at 10kN per level. Carry out step-by-step loading, and collect all data after holding the load for 3 minutes after each level; the specific loading steps are as follows:

1. From the beginning of loading to the critical concrete cracking, load according to each level of 5kN load;

2. From the cracking of the concrete to the occurrence of cracks with a width of 0.5mm near each control section, load according to the load of 10kN per level;

3. From the maximum crack width of the test beam exceeding 0.5mm to the final failure of the adjacent structure, the load shall be loaded at each level of 5kN.

The specific implementation methods described in the present invention do not constitute a limitation to the scope of the application. Any modifications, equivalent replacements and improvements that can be made by professionals in the field within the spirit and principles of the present invention should be included in this application. within the scope of protection of the invention.

Claims (1)

1. A continuous beam test method is characterized in that, comprising load cell, screw jack, electronic displacement gauge, reaction force frame, hydraulic jack; after the test device is connected, before the formal test, the test beam should be preloaded at first , to check whether the test instruments are working normally and whether the test beam is placed stably and centered; the preload is 10% of the calculated cracking load, unload slowly after loading, and adjust the test instruments according to the preload results; Loading in stages according to the calculated failure load value, because the oil pump is used for loading, in order to better control the loading speed and obtain a relatively stable deformation value when observing the structure, the test is carried out in stages at 10kN per stage, and after each stage All data were collected after 3 minutes of loading; the specific loading steps are as follows: (1) From the beginning of loading to the critical concrete cracking, load according to each level of 5kN load; (2) From the cracking of the concrete to the occurrence of cracks with a width of 0.5mm near each control section, the load shall be loaded at 10kN per level; (3) From the time when the maximum crack width of the test beam exceeds 0.5mm to the final failure of the adjacent structure, a load of 5kN per level is applied.