GB/T 50315: Evolution and historical versions
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| GB/T 50315-2011 | English | RFQ |
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Technical standard for site testing of masonry engineering
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GB/T 50315-2011
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| GB/T 50315-2000 | English | RFQ |
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The masonry project site detection technology standards
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GB/T 50315-2000
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PDF similar to GB/T 50315-2011
Standard similar to GB/T 50315-2011 GB 55007 GB 50204 GB 50211 GB 50924 Basic data | Standard ID | GB/T 50315-2011 (GB/T50315-2011) | | Description (Translated English) | Technical standard for site testing of masonry engineering | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | P24 | | Classification of International Standard | 91.080.30 | | Word Count Estimation | 115,160 | | Date of Issue | 2011-07-29 | | Date of Implementation | 2012-03-01 | | Older Standard (superseded by this standard) | GB/T 50315-2000 | | Quoted Standard | GB 50003; GB/T 50129; GB 50203-2002; GB 50203-2011; GB 50300; GB/T 2419; GB/T 4883; JGJ/T 234 | | Regulation (derived from) | Ministry of Housing and Urban Notice No. 1108 | | Issuing agency(ies) | Ministry of Housing and Urban-Rural Development of the People's Republic of China; General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China | | Summary | This standard applies to: engineering brick masonry, mortar and masonry block field testing and strength presumption. | GB/T 50315-2011: Technical standard for site testing of masonry engineering---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
1 General
1.0.1 This standard is formulated in order to implement the national technical policy in the on-site inspection of masonry projects, to achieve advanced technology, accurate data, safety and reliability.
1.0.2 This standard is applicable to on-site testing and strength estimation of brick masonry, masonry mortar and masonry blocks in masonry projects.
1.0.3 The on-site inspection of masonry works shall not only comply with this standard, but also comply with the current relevant national standards.
2 Terms and symbols
2.1 Terminology
2.1.1 Detection unit test unit
Masonry with the same material type and design strength grade for each floor with a total amount not greater than 250m3.
2.1.2 Test zone
In a detection unit, one or several detection areas are randomly arranged.
2.1.3 Test point
In a survey area, one or several test points are randomly arranged according to the requirements of the test method.
2.1.4 The method of axial compression in situ
A method for testing the compressive strength of masonry by using an in-situ press to conduct a compressive test on the wall.
2.1.5 The method of flat jack in situ
The method of testing the compressive stress, elastic modulus and compressive strength of the masonry by using a flat hydraulic jack on the wall is referred to as the flat top method.
2.1.6 The method of test on specimen cut from wall
The method of cutting and taking out the external geometric dimensions from the wall as a standard compressive masonry specimen, and transporting it to the laboratory for compressive testing.
2.1.7 The method of shear along one horizontal mortar joint in situ
The method of testing the shear strength of the masonry by performing a shear test along a single horizontal mortar joint on the wall is referred to as the in-situ single shear method.
2.1.8 The method of shear along two horizontal mortar joint in situ
A method for testing the shear strength of masonry by using an in-situ shear instrument to conduct double-sided shear tests on single or double bricks on the wall.
2.1.9 The method of push out
A push-out instrument is used to push out a single small brick horizontally from the wall, and measure the horizontal thrust and the fullness of the mortar under the pushed brick, so as to determine the compressive strength of the masonry mortar.
2.1.10 The method of compression in cylinder
The sampled mortar is crushed, dried and sieved into particles that meet a certain gradation requirement, loaded into a pressure-bearing cylinder and subjected to a cylinder pressure load to detect the degree of damage (cylinder pressure ratio), and the compressive strength of the masonry mortar is estimated according to the cylinder pressure ratio Methods.
2.1.11 The method of shear on mortar flake
It is a method to estimate the compressive strength of masonry mortar by using a mortar strength tester to detect the shear strength of the mortar sheet.
2.1.12 The method of mortar rebound
A mortar rebound tester is used to detect the hardness of the mortar surface in the wall and column, and the strength is estimated according to the rebound value and carbonization depth.
2.1.13 The method of point load
A method of estimating the compressive strength of masonry mortar by applying a point load on the large surface of the mortar sheet.
2.1.14 The method of local compression on mortar flake
The local compressive test is carried out on the mortar sheet specimen by using the partial pressure instrument, and the compressive strength of the masonry mortar is estimated according to the local compressive load value.
2.1.15 The method of fired brick rebound
The hardness of the surface of sintered ordinary bricks or sintered porous bricks is detected by a special rebound tester, and the compressive strength is estimated according to the rebound value.
2.1.16 Masonry between two channels
The masonry between two horizontal grooves excavated when the compressive strength of the masonry is tested on the brick wall by the in-situ axial compression method and the flat top method.
2.1.17 Cylindrical compressive ratio
When the cylinder pressure method is used to test the mortar strength, after the mortar sample is tested and sieved by the cylinder pressure, the ratio of the cumulative sieve residue remaining above the sieve with an aperture of 5 mm to the total amount of the sample is referred to as the cylinder pressure ratio.
2.2 Symbols
2.2.1 Geometric parameters
A——the cross-sectional area of the member or test piece;
b——width; side length of specimen section;
h—height; section height of specimen; distance between measuring points;
l - length;
d——mortar carbonation depth;
r—radius; the radius of action of the point load method;
t—thickness; thickness of specimen;
H - the height of the masonry compression test piece.
2.2.2 Function, effect and resistance, calculation index
N——measured failure load value;
fm—average value of masonry compressive strength;
fv,m—average value of masonry shear strength;
τ——shear strength of mortar sheet;
f1——the compressive strength value of the brick;
f2——compressive strength value of masonry mortar;
f2'—the estimated value of compressive strength of masonry mortar;
σ0——The average compressive stress of the upper wall of the measuring point.
2.2.3 Coefficients
ξ1——Conversion coefficient for measuring masonry compressive strength by in-situ axial compression method and flat top method;
ξ2——brick variety correction coefficient of push-out method;
ξ3——mortar fullness correction coefficient of push-out method;
ξ4——Correction coefficient of load action radius of point load method;
ξ5——Correction coefficient of specimen thickness by point load method.
2.2.4 Others
B - Mortar fullness of horizontal mortar joints;
η——the cylinder pressure ratio in the cylinder pressure method;
R - rebound value of brick or mortar;
n1——the number of measuring points (location) in the same measuring area;
n2——the number of measuring areas of the same detection unit.
3 Basic Regulations
3.1 Applicable conditions
3.1.1 For new masonry projects, the inspection and evaluation of the strength of masonry mortar or brick and brick masonry shall be in accordance with the current national standards "Code for Design of Masonry Structures" GB 50003, "Code for Acceptance of Construction Quality of Masonry Structure Engineering" GB 50203, "Unified Standards for Construction Quality Acceptance of Construction Engineering" GB 50300, "Standards for Test Methods of Basic Mechanical Properties of Masonry" GB/T 50129 and other relevant provisions shall be implemented; when one of the following situations is encountered, the masonry shall be tested and presumed according to this standard The strength of mortar or brick and brick masonry.
1 The mortar test block lacks representativeness or the number of test blocks is insufficient.
2 If there is any doubt or controversy about the test results of brick strength or mortar test block, it is necessary to determine the actual masonry compressive and shear strength.
3 In the event of engineering accidents or doubts and disputes about the construction quality, further analysis of the strength of bricks, mortar and masonry is required.
3.1.2 For existing masonry projects, when carrying out the following identification, the mortar strength, brick strength or masonry working stress, elastic modulus and strength shall be tested and estimated according to this standard.
1 Safety identification, identification of dangerous houses and other emergency identification.
2 Seismic identification.
3 Reliability appraisal before overhaul.
4 Special appraisal before the house is changed in use, remodeled, added floors or expanded.
3.1.3 The selection of various detection methods should be carried out in accordance with the provisions of Section 3.4 of this standard.
3.2 Testing procedures and work content
3.2.1 On-site inspection work should be carried out according to the prescribed procedures (Figure 3.2.1)
3.2.2 The investigation phase should include the following work contents.
1 Collect the drawings of the inspected project, construction acceptance data, types of bricks and mortars and testing data of relevant raw materials.
2 On-site investigation of the structural form, environmental conditions, masonry quality and existing problems of the project. For existing masonry projects, the changes during the use period should be investigated.
3 Construction time of the project.
4 Further clarify the reasons for testing and the specific requirements of the entrusting party.
5.Previous project quality inspections.
3.2.3 The testing plan should be formulated according to the investigation results and testing purpose, content and scope, and one or more testing methods should be selected, and the entrusting party should be consulted and approved if necessary. The inspected project should be divided into inspecting units, and the survey area and the number of survey points should be determined.
3.2.4 Test equipment and instruments should be maintained and calibrated according to the relevant standards and product instructions, and if necessary, the number of calibrations should be appropriately increased according to the frequency of use and the importance of the test object.
3.2.5 In the process of calculation, analysis and strength estimation, when there are abnormal situations or insufficient test data, the test should be supplemented in time.
3.2.6 After the testing work is completed, a test report meeting the testing purpose shall be issued in time.
3.2.7 At the end of the on-site test, if the masonry is partially damaged due to the test, the local damaged part of the masonry should be repaired in time. The repaired masonry shall meet the requirements of the bearing capacity and normal use of the original components.
3.2.8 Personnel engaged in testing and strength presumption shall take part in testing and write reports after passing special training.
3.2.9 For on-site testing work, safety measures should be taken to ensure personal safety and prevent instrument damage, and measures should be taken to avoid or reduce environmental pollution.
3.2.10 For on-site testing and sampling testing, the ambient temperature and the temperature of the test piece (sample) should be higher than 0°C.
3.3 Detection unit, measurement area and measurement points
3.3.1 When the detection object is the whole building or a part of the building, it should be divided into one or several structural units that can be analyzed independently, and each structural unit should be divided into several detection units.
3.3.2 There should not be less than 6 measurement areas in each detection unit, and a single component (single wall, column) should be regarded as a measurement area. When a detection unit has less than 6 components, each component should be regarded as a measurement area.
In-situ axial compression method, flat top method, and cut compression test piece method are used for detection. When it is really difficult to select 6 measurement areas, no less than 3 measurement areas can be selected for testing, but it should be combined with other non-destructive detection methods. Comprehensive strength estimation.
3.3.3 Several measuring points should be arranged randomly in each measuring area. The number of measuring points for various detection methods shall meet the following requirements.
1 For the in-situ axial compression method, flat top method, cut compression test piece method, in-situ single shear method, and cylinder compression method, the number of measuring points shall not be less than one.
2 In-situ double-shear method and push-out method, the number of measuring points should not be less than 3.
3 For the mortar sheet shearing method, mortar rebound method, point load method, mortar sheet partial pressure method, and fired brick rebound method, the number of measuring points shall not be less than 5.
Note. The position measurement of the rebound method is equivalent to the measurement points of other detection methods.
3.3.4 When inspecting existing buildings or only part or individual parts of the building at the request of the entrusting party, the number of survey areas and points can be reduced, but the number of survey areas for one inspection unit should not be less than 3.
3.3.5 The arrangement of measuring points shall enable the test results to comprehensively and reasonably reflect the construction quality of the testing unit or its mechanical performance.
3.4 Classification of detection methods and selection principles
3.4.1 On-site inspection methods for masonry works can be divided into the following categories according to the degree of damage to the masonry structure.
1 Non-destructive testing method, which has no influence on the existing mechanical properties of the masonry structure during the testing process.
2 Local damage detection method, in the detection process, there is a partial and temporary impact on the existing mechanical properties of the masonry structure, but it can be repaired.
3.4.2 On-site detection methods of masonry works can be divided into the following categories according to the test content.
1 The compressive strength of masonry can be tested by in-situ axial compression method, flat roof method, and cut compression test piece method.
2 The flat top method can be used to detect the working stress and elastic modulus of masonry.
3 In-situ single-shear method and in-situ double-shear method can be used to detect the shear strength of masonry.
4 The strength of masonry mortar can be tested by push-out method, cylinder pressure method, mortar sheet shearing method, mortar rebound method, point load method, and mortar sheet partial pressure method.
5 To test the compressive strength of masonry blocks, the rebound method and sampling method of sintered bricks can be used.
3.4.3 The detection method can be selected according to Table 3.4.3.
3.4.4 The selection of detection methods and the selection of measuring points on the wall should still meet the following requirements.
1 Except for the in-situ simple shear method, the measuring point should not be located at the opening of doors and windows.
2 The measuring points of all methods should not be located near the temporary construction openings of the supplementary masonry.
3 Within the calculated height range of the walls at stress concentration locations and wall beams, the detection method with relatively large local damage should not be selected.
4 For brick columns and load-bearing walls with a width less than 3.6m, the detection method with relatively large local damage should not be selected.
3.4.5 During on-site inspection or sampling inspection, the age of masonry mortar should not be less than 28d.
3.4.6 When testing the strength of masonry mortar, the mortar sample or the horizontal mortar joint for in-situ testing should be in a dry state.
3.4.7 Sampling and testing of various bricks, each testing unit should not be less than one group; the compressive strength test and strength grade evaluation of bricks should be carried out according to the corresponding product standards.
3.4.8 When the strength of the masonry mortar is tested by the partial pressure method of the mortar sheet, the determination of the detection unit, the measurement area, and the strength estimation shall be carried out in accordance with the relevant provisions of this standard; the test equipment, test procedures, and data analysis shall be in accordance with the current industry standards. The relevant provisions of the standard "Technical Regulations for Testing the Compressive Strength of Masonry Mortar by Selective Pressure Method" JGJ/T 234 shall be implemented.
4 In situ axial compression method
4.1 General provisions
4.1.1 The in-situ axial compression method (Fig. 4.1.1) is suitable for estimating the compressive strength of 240mm thick ordinary brick masonry or porous brick masonry.
4.1.2 The test site should be representative and meet the following requirements.
1 The test site should be selected at a height of about 1m from the building and the ground in the middle of the wall; the wall width on each side of the inter-trough masonry should not be less than 1.5m.
2 On the same wall, there should not be more than one measuring point, and it should be selected at the middle part along the length of the wall; if more than one, the horizontal clear distance should not be less than 2.0m.
3 The test site shall not be selected under the cantilever beam, the stress concentration site and the calculated height range of the wall of the wall beam.
4.2 Specifications of test equipment
4.2.1 The main technical indicators of the in-situ press shall meet the requirements in Table 4.2.1.
4.2.2 The force value of the in-situ press should be checked every six months.
4.3 Test steps
4.3.1 When digging horizontal slots on the measuring points, the following requirements should be met.
1 The dimensions of the upper and lower horizontal grooves are to comply with the requirements in Table 4.3.1.
2 The upper and lower horizontal slots should be aligned. For ordinary brick masonry, the height of the masonry between the grooves should be 7 skin bricks; for porous brick masonry, the height of the masonry between the grooves should be 5 skin bricks.
3 When slotting, avoid disturbing the surrounding masonry; the bearing surface of the masonry between the slots should be smoothed.
4.3.2 When the in-situ press (Figure 4.1.1) is placed between the slot holes, the following requirements shall be met.
1 On the lower surface of the upper tank and the top surface of the flat jack, a cushion layer of materials such as wet fine sand or gypsum should be evenly laid respectively, and the thickness of the cushion layer can be 10mm.
2 The reaction force plate should be placed in the upper slot, the flat jack should be placed in the lower slot, four steel tie rods should be placed, and after the two pressure bearing plates are aligned up and down, the nuts should be tightened evenly in pairs along the diagonal and Adjust its parallelism; the net distance error between the upper and lower nuts of the four steel tie rods should not be greater than 2mm.
3 Before the formal test, a test load test should be carried out, and the value of the test load can be 10% of the estimated failure load. The flexibility and reliability of the test system should be checked, as well as whether the contact between the upper and lower pressure plates and the pressure surface of the masonry is even and dense. After the test load is applied, the load should be unloaded after the test system is normal, and the formal test should start.
4.3.3 During the formal test, loads should be applied step by step. Each level of load can be taken as 10% of the estimated failure load, and should be added evenly within 1min to 1.5min, and then the dead load is 2min. After loading to 80% of the estimated failure load, it should be loaded continuously at the original loading speed until the masonry between the grooves fails. When the cracks in the masonry between the grooves expand and increase sharply, and the pointer of the oil pressure gauge retreats obviously, the masonry between the grooves reaches the limit state.
4.3.4 During the test, if it is found that the upper and lower pressure plates are in poor contact with the bearing surface of the masonry, causing the masonry between the grooves to be under local or eccentric compression, the test should be stopped, the test device should be adjusted, and the test should be retested. When adjusting, the measuring point should be replaced.
4.3.5 During the test, the initial cracks and the development of cracks in the masonry between the grooves should be carefully observed, and the readings of the oil pressure gauge, the location of the measuring points, and the schematic diagram of the cracks changing with the load should be recorded under step-by-step loading.
4.4 Data Analysis
4.4.1 According to the readings of the oil pressure gauge at the initial crack and damage of the masonry between the grooves, the initial reading of the oil pressure gauge should be subtracted respectively, and the initial crack of the masonry between the grooves should be calculated according to the calibration results of the in-situ press load values and failure load values.
4.4.2 The compressive strength of masonry between grooves shall be calculated according to the following formula.
4.4.3 The compressive strength of inter-groove masonry is converted to the compressive strength of standard masonry, which shall be calculated according to the following formula.
4.4.4 The average compressive strength of masonry in the survey area shall be calculated according to the following formula.
5 flat top method
5.1 General provisions
4 During the formal test, the loading method should comply with the provisions of Article 4.3.3 of this standard.
5 When the compressive stress on the upper part of the inter-trough masonry is less than 0.2MPa, the test shall be carried out after adding a counter balance frame. When the compressive stress on the upper part of the inter-trough masonry is not less than 0.2MPa, it is also advisable to add a counter force balance frame before testing. The reaction balance frame can be made up of two reaction plates and four steel tie rods.
5.3.3 When testing the elastic modulus of masonry under compression, the following requirements should also be met.
1 A pair of deformation measurement footmarks [Figure 5.1.1(b)] shall be pasted on both sides of the masonry between the grooves, and the feet shall be located in the middle of the masonry between the grooves. The distance between the foot marks of ordinary brick masonry should be separated by 4 horizontal mortar joints, preferably 250mm; the distance between the foot marks of porous brick masonry should be separated by 3 horizontal mortar joints, preferably 270mm~300mm. The gauge length value should be recorded before the test, and should be accurate to 0.1mm.
2 Before the formal test, 10% of the estimated failure load should be applied repeatedly, and the number of times should not be less than 3 times.
3 During the test, the loading method should meet the requirements of Article 4.3.3 of this standard, and the deformation value under the step-by-step loading should be recorded.
4 The upper limit of cumulative loading stress should not be greater than 50% of the ultimate compressive strength of masonry between grooves.
5.3.4 When only the masonry compressive strength is to be measured, two horizontal grooves shall be excavated at the same time, and the test shall be carried out according to the requirements of Article 5.3.2 of this standard.
5.3.5 The content of the test record shall include the layout of the measuring points, the masonry method of the wall, the position of the flat roof, the position of the foot mark, the axial deformation value, the reading of the oil pressure gauge under the load step by step, and the schematic diagram of the change of cracks with the load. wait.
5.4 Data analysis
5.4.1 During data analysis, the reading of the oil pressure gauge should be converted into the test load value according to the verification result of the flat jacking force value.
5.4.2 The compressive working stress of the wall shall be equal to the corresponding stress value when the measured deformation value reaches the reading before excavation according to Article 5.3.1 of this standard.
5.4.3 The compressive elastic modulus of masonry under the condition of lateral restraint shall be calculated according to the relevant provisions of the current national standard "Standard for Test Methods of Basic Mechanical Properties of Masonry" GB/T 50129; When compressing the modulus of elasticity, the calculation result should be multiplied by the conversion factor 0.85.
5.4.4 The compressive strength of masonry between grooves shall be calculated according to formula (4.4.2) of this standard.
5.4.5 The compressive strength of masonry between grooves is converted to the compressive strength of standard masonry, and it shall be calculated according to formula (4.4.3-1) and formula (4.4.3-2) of this standard.
5.4.6
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