Some standard content:
Industry Standard of the People's Republic of China
Standard of Dangerous Building Appraisal
Standard of Dangerous Building AppraisalJGJ125-99
Editor: Chongqing Municipal Land and Housing Administration BureauApproval Department: Ministry of Construction of the People's Republic of ChinaImplementation Date: March 1, 2000
6-7-1
Notice on the Issuance of the Industry Standard "Standard of Dangerous Building Appraisal"
Construction Standard [1999] No. 277
According to the requirements of the Ministry of Construction's "Notice on Issuing the 1999--Project Construction Industry Standard Formulation and Revision Project Plan (First Batch)" (Construction Standard [1991] No. 413), the "Standard of Dangerous Building Appraisal" edited by the Chongqing Municipal Land and Housing Administration Bureau has been reviewed and approved as a mandatory industry standard, numbered JGJ125-99. 25-99, effective from March 1, 2000. The original Ministry standard "Dangerous House Appraisal Standard" CJ13-86 is abolished at the same time.
According to the requirements of the Ministry of Construction's Document No. 413 [1991], the standard drafting group has formulated this standard after extensive investigation and research, careful summary of practical experience, reference to relevant international standards and foreign advanced standards, and extensive solicitation of opinions.
The main technical contents of this standard are: 1. General provisions; 2. Symbols and codes; 3. Appraisal procedures and assessment methods; 4. Component hazard appraisal; 5. House hazard appraisal; 6. House safety appraisal report, etc. The main technical contents of the revision are: 1. Supplementation of the scope of application of the standard; 2. Addition of symbols , Code Chapter; 3. Added identification procedures and assessment methods; 4. Added steel structure component identification; 5.67--2
This standard is managed by the Shanghai Real Estate Science Research Institute, the technical unit of the Ministry of Construction's real estate standards, and the Chongqing Land and Housing Administration Bureau is responsible for the specific interpretation. The Ministry of Construction's Standards and Norms Research Institute organized the China Building Industry Press to publish it.
Ministry of Construction of the People's Republic of China
November 24, 1999
Added the appendix Housing Safety Appraisal Report; 6. Based on the fuzzy set theory, a hierarchical comprehensive evaluation model was established. This standard is managed by the Shanghai Real Estate Science Research Institute, the technical unit of the Ministry of Construction's real estate standards, and authorized by the main The editing unit is responsible for the specific explanation.
The main editing unit of this standard is: Chongqing Land and Housing Administration Bureau (Address: No. 74 Renhe Street, Yuzhong District, Chongqing; Postal Code 400015) The participating units of this standard are: Shanghai Real Estate Science Research Institute The main drafters of this standard are: Chen Huifang, Qi Zhengting, Gu Fangzhao, Zhao Weimin, Si Zifang, Zhou Yun, Zhang Nengjie 1
Symbols and codes
2.5 Symbols
2.2 Codes
3 Identification procedures and assessment methods
3.1 Identification procedures
3.2 Assessment methods
Component hazard assessment
2--General provisions
Foundation
. 6--7--4
6—7—4
· 6--7—4
6-7--5
Masonry structural components
Masonry structural components
4.5 Concrete structural components
4.6 Steel structural components
5 Building hazard assessment
-General provisions
Grade classification
Comprehensive assessment principles
6—7-
: 6—-7-7
6—7~7
. 6--7--7
..++. 6-7-7
Comprehensive assessment method
1+++++++++++++-+ 677
Appendix A
Building safety assessment report． ． ··
Explanation of terms used in this standard
6—7—3
1 General
1.0.1 This standard is formulated to effectively utilize existing buildings, correctly judge the degree of danger of building structures, promptly manage dangerous buildings, and ensure safe use.
1.0.2 This standard applies to the hazard assessment of existing buildings. 1.0.3 The assessment of dangerous buildings and the hazard assessment of industrial buildings and public buildings, protective buildings and high-rise buildings with special requirements, as well as buildings under accidental effects, in addition to complying with the provisions of this standard, shall also comply with the provisions of the relevant national mandatory standards in force. 2 Symbols and codes
The symbols used in the hazard assessment of buildings and their meanings shall comply with the following provisions:
nI ctnh
Pestmn
-Calculated span;
-Calculated height;
-Number of components;
Number of dangerous columns;
Number of dangerous wall sections:
Number of dangerous main beams:
-Number of dangerous secondary beams;
Number of dangerous boards;
Number of columns;
Number of main beams;
Number of secondary beams;
Number of wall sections;
Number of boards;
Number of dangerous components:
Number of roof trusses;||tt| |Number of dangerous roof trusses:
Percentage of dangerous components (dangerous points);
Percentage of dangerous components (dangerous points) in foundation;Percentage of dangerous components (dangerous points) in load-bearing structures;Percentage of dangerous components (dangerous points) in enclosure structures;Resistance of structural components:
Effect of structural components;
Subjectivity;
-Subjectivity of Class A of the house;
Subjectivity of Class B of the house;
Subjectivity of Class C of the house;
Subjectivity of Class D of the house;
.Subjectivity of Class A of the house component;
-Subjectivity of Class b of the house component;
6—7—4
μ bes
μu ces
the membership degree of the building component C level;
the membership degree of the building component D level;
the membership degree of the foundation A level;
the membership degree of the foundation B level;
the membership degree of the foundation C level;Www.bzxZ.net
the membership degree of the foundation D level;
the membership degree of the upper load-bearing structure A level;
the upper load-bearing structure b-level membership;
c-level membership of the upper load-bearing structure;
d-level membership of the upper load-bearing structure;
a-level membership of the enclosure structure;
b-level membership of the enclosure structure;
d-level membership of the enclosure structure;
d-level membership of the enclosure structure;
d-level membership of the enclosure structure;
d-level membership of the enclosure structure;
d-level importance coefficient of structural components;
a-slope.
The codes used in the building hazard assessment and their meanings shall comply with the following provisions:
a, b, c, d-
A, B, C, D
Dangerous assessment levels of building components; Building hazard assessment levels;
Non-dangerous components;
T.-Dangerous components.
3 Appraisal Procedure and Assessment Method
3.1 Appraisal Procedure
3.1.1 The appraisal of housing hazards shall be carried out in accordance with the following procedures: 1 Acceptance of entrustment: Determine the content and scope of housing hazard appraisal according to the client's requirements;
2 Initial investigation: Collect, investigate and analyze the original data of the house, and conduct on-site investigation;
3 Inspection and verification: Conduct on-site inspection of the current status of the house, and use instrument testing and structural verification when necessary; 4 Appraisal rating: Conduct a comprehensive analysis and comprehensive assessment of the data and information of investigation, investigation, inspection and verification to determine its hazard level; 5 Treatment suggestions: Principled treatment suggestions shall be put forward for the appraised house;
6 Issue report: The report format shall comply with the provisions of Appendix A. 3.2 Assessment method
3.2.1 Comprehensive assessment shall be carried out at three levels. 3.2.2 The first level shall be the appraisal of component hazard, and its rating shall be divided into two categories: dangerous components (T) and non-dangerous components (F). 3.2.3 The second level should be the hazard assessment of the building components (foundation, upper load-bearing structure, enclosure structure), and its grading should be divided into four levels: A, B, C, and D.
3.2.4 The third level should be the hazard assessment of the building, and its grading should be divided into four levels: A, B, C, and D.
4 Component hazard assessment
4.1 General provisions
4.1.1 Dangerous components refer to structural components whose bearing capacity, cracks, and deformation cannot meet the requirements of normal use. 4.1.2 The division of a single component shall comply with the following provisions: 1 Foundation
1) Independent column foundation: a single foundation of a column is a component; 2) Strip foundation: a single-sided length of an axis line of a natural room is a component;
3) Plate foundation: an area of a natural room is a component. 2 Wall: a calculated height and a side of a natural room are a component.
3 Column: a calculated height and a
root are a component.
4 Beams, bars, joists, etc.: a span and a root are a component.
5 Plate: an area of a natural room is a component; prefabricated plates are a piece as a component.
6 Roof trusses, trusses, etc.: a couch is a component. 4.2 Foundation
4.2.1 The hazard assessment of foundations shall include two parts: foundation and foundation.
4.2.2 The foundation should focus on the inspection of the oblique step cracks, horizontal cracks, and vertical cracks at the connection between the foundation and the load-bearing brick wall, the horizontal cracks at the connection between the foundation and the root of the frame column, the tilt displacement of the house, the landslide, stability, special soil deformation and cracking of the foundation.
When the foundation part has any of the following phenomena, it should be assessed as a dangerous state:
1 The foundation settlement rate is greater than 2mm/month for 2 consecutive months, and there is no termination trend in the short term;
2 The foundation produces uneven settlement, and its settlement is greater than the allowable value specified in the current national standard "Code for Design of Building Foundations" (GBJ7-81), the width of the settlement cracks on the upper wall is greater than 10mm, and the local inclination rate of the house is greater than 1%;
3 The foundation is unstable and slips, the horizontal displacement is greater than 10mm, and it has a significant impact on the upper structure, and there are still signs of continued sliding.
4.2.4 When the foundation of a house has any of the following phenomena, it should be assessed as a dangerous point:
1 The bearing capacity of the foundation is less than 85% of the foundation effect (R/%oS<0.85);
2 The foundation is aged, corroded, broken, or broken, resulting in obvious tilt, displacement, cracks, and distortion of the structure; 3 The foundation has slipped, and the horizontal displacement speed has been greater than 2mm/month for two consecutive months, and there is no end trend in the short term. 4.3 Masonry structural components
4.3.1 The hazard assessment of masonry structural components should include bearing capacity, structure and connection, cracks and deformation, etc. 4.3.2 When it is necessary to verify the bearing capacity of masonry structural components, the strength grade of the blocks and mortar should be measured, the masonry strength should be estimated, or the masonry strength should be directly tested. The effective value of the masonry section should be measured, and the section loss caused by various factors should be deducted.
4.3.3 Masonry structures should focus on checking the structural connection parts of the masonry, the oblique or vertical cracks at the intersection of the vertical and horizontal walls, the deformation and cracks of the masonry load-bearing walls, and the cracks and displacement of the arch foot. Pay attention to the width, length, depth, direction, number and distribution of the cracks, and observe their development.
4.3.4 Masonry structural members with any of the following phenomena shall be assessed as dangerous points:
1 The bearing capacity of the compressive member is less than 85% of its action effect (R/YoS<0.85);
2 Vertical cracks with a width greater than 2mm and a length exceeding 1/2 of the storey height are generated in the compressive wall or column along the direction of force, or multiple vertical cracks with a length exceeding 1/3 of the storey height are generated;
3 The surface of the compressive wall or column is weathered and peeled off, the mortar is powdered, and the effective section is weakened by more than 1/4;
4 The wall or column section at the end of the supporting beam or roof truss has multiple vertical cracks due to local compression, or the crack width has exceeded 1mm; 5 Horizontal cracks are generated in the wall and column due to eccentric compression, and the width of the crack is greater than 0.5mm ;
6 The wall or column tilts, and the tilt rate is greater than 0.7%, or the adjacent wall joints are broken into through cracks;
7 The wall or column rigidity is insufficient, and flexural flashing occurs, and horizontal or cross cracks appear at the flexural parts;
8 Obvious vertical cracks appear in the middle of the brick lintel, or obvious oblique cracks appear at the end, or horizontal cracks appear in the wall supporting the lintel, or obvious bending and sinking deformation occurs; 9 Brick simple arch, flat shell, corrugated simple arch, arch top cracks along the generatrix, or the arch surface is obviously deformed, or the arch foot is obviously displaced, or the arch body tie rod is seriously corroded, and the tie rod system fails;
10 The height-to-thickness ratio of the stone wall (or earth wall): single-layer is greater than 14, two-layer is greater than 12, and the free length of the wall is greater than 6m. The eccentricity of the wall reaches 1/6 of the wall thickness.
4.4 Timber structural members
4.4.1 The risk assessment of timber structural members shall include the bearing capacity, structure and connection, cracks and deformation, etc. 4.4.2 When the bearing capacity of timber structural members needs to be verified, the mechanical properties, defects, decay, insect infestation of timber and the mechanical properties and rust of iron parts shall be tested. The effective value of the cross section of the timber member shall be 6-7-5
deducted from the cross section loss caused by various factors. 4.4.3 The structural members should be inspected for decay, insect infestation, wood defects, structural defects, deformation of structural members, instability, cracks on the shear surface of the end nodes of the wooden truss, out-of-plane deformation of the truss and stability of the roof support system.
4.4.4 The structural members with any of the following phenomena should be assessed as dangerous points:
1 The bearing capacity of the wooden structural member is less than 90% of its effect (R/Y(S<0.90);
2 The connection method is improper and the structure has serious defects, which has caused the node to loosen, deform, slip, crack along the shear surface, shear damage or serious rust and looseness of the iron parts resulting in connection failure; 3 The main beam has a deflection greater than Ln/150, or the tension zone is accompanied by serious material defects;
4 The roof truss has a deflection greater than Lo/120, and the top or end nodes are decayed or split, or out-of-plane tilting occurs. The inclination exceeds h/120 of the roof truss height;
5 The deflection of the bars and joists is greater than Lu/120, and the wooden parts of the walls are rotten, worm-eaten or hollow;
6 The wooden columns are lateral and deformed, and their sagittal height is greater than h/150, or the top of the column is split and the column body is broken. The foot of the column is rotten, and the rotten area is more than 1/5 of the original cross-section;
7 For tension, bending, eccentric compression and axial compression members, the slope p of the oblique texture or oblique crack is greater than 7%, 10%, 15% and 20% respectively:
8 There are any wooden components with heart rot defects. 4.5 Concrete structural members
4.5.1 The hazard assessment of concrete structural members should include bearing capacity, structure and connection, cracks and deformation. 4.5.2 When it is necessary to verify the bearing capacity of concrete structural members, the concrete strength, carbonization and steel bar of the members should be checked. The mechanical properties, chemical composition and corrosion conditions shall be tested; the effective value of the cross section of the concrete component shall be measured, and the cross section loss caused by various factors shall be deducted. 4.5.3 Concrete structural components shall focus on checking the stress cracks and main reinforcement corrosion conditions of columns, beams, slabs and roof trusses, horizontal cracks at the root and top of the column, roof truss inclination and support system stability. 4.5.4 Concrete components with any of the following phenomena shall be assessed as dangerous points:
The bearing capacity of the component is less than 85% of the effect of the action (R/%oS<0.85);
2 The beam and slab produce a deflection of more than 1-0/150, and the crack width in the tension zone is greater than 1mm;
3 Vertical cracks appear in the tension zone at the mid-span of simply supported beams and continuous beams, one side of which extends upward to more than 2/3 of the beam height, and the crack width is greater than 0.5mm, or shear diagonal cracks appear near the support, and the crack width is large. 0.4mm;
4 Transverse horizontal cracks and oblique cracks occur at the main reinforcement of beams and slabs, with a crack width greater than 1mm, and the slabs produce tensile cracks with a width greater than 0.4mm;
5 Beams and slabs produce cracks along the main reinforcement direction due to corrosion of the main reinforcement, with a crack width greater than 1mm, or the concrete of the component is seriously defective, or the concrete protective layer is seriously detached and the reinforcement is exposed;
6 Cracks occur around the surface of the cast-in-place slab, or cross cracks occur at the bottom of the slab:
Prestressed beams and slabs produce vertical cracks; or the end concrete is loose and exposed, with a length of more than 100 times the diameter of the main reinforcement; 8 Vertical cracks occur in the compression column, the protective layer peels off, and the main reinforcement is exposed and corroded; or horizontal cracks occur on one side, with a crack width greater than 1mm, and the concrete on the other side is crushed, and the main reinforcement is exposed and corroded; 9 Cross cracks occur in the middle of the wall, with a crack width greater than 0.4mm
10 The column or wall tilts or moves, and the tilt rate exceeds 1% of the height, and the lateral displacement is greater than h/500; 11 The concrete of the column or wall is cracked, carbonized, and bulged, and the damage surface is greater than 1/3 of the full section, and the main reinforcement is exposed, severely corroded, and the section is reduced;
2 The column or wall lateral deformation, the limit value is greater than h/250, or 12
is greater than 30mm;
13 The roof truss has a deflection greater than L/200, and the lower chord is Transverse cracks and crack width greater than 1mm;
14 The failure of the support system of the roof truss leads to tilting, and the tilt rate is greater than 2% of the height of the roof truss;
15 The protective layer of the compression and bending members is peeled off, and the main reinforcement is exposed and corroded in many places; the end node connection is loose, and there are obvious deformation cracks; 16 The effective shelving length of the beam and slab is less than 70% of the specified value 4.6 Steel structure components
4.6.1 The hazard assessment of steel structure components should include bearing capacity, structure and connection, deformation, etc.
4.6.2 When it is necessary to verify the bearing capacity of steel structure components, the mechanical properties, chemical composition, and corrosion of the materials should be tested. The effective value of the cross section of the measured steel component should be deducted from the cross section loss caused by various factors.
4.6.3 For steel structure components, the welds, bolts, rivets, etc. at each connection node should be checked in particular; attention should be paid to the connection between steel columns and beams, the damage to the support rods, the connection between the column foot and the foundation, the bending of steel truss rods, the distortion of the cross section, the bending of the node plate, and the deflection, lateral inclination and other deviations of the steel truss.
4.6.4 Steel structure members with any of the following phenomena shall be assessed as dangerous points:
The bearing capacity of the member is less than 90% of its effect (R/%S<0.9);
2 There are cracks or sharp-angle cuts in the member or connector; the welds, bolts or rivets are seriously damaged such as pulling apart, deformation, slipping, loosening, shearing, etc.:
3 The connection method is improper and the structure has serious defects; 4 The cross-section of the tension member is reduced by more than 10% of the original cross-section due to rust;
45mm;
The deflection of beams, plates and other members is greater than Lo/250, or greater than 6 The lateral bending height of the solid beam is greater than L0/600, and there are signs of development:
7 Compression members The slenderness ratio is greater than 1.2 times the value specified in the current national standard "Code for Design of Steel Structures" (GIBJ1788): 8 The displacement of the top of the steel column is greater than h/150 in the plane, greater than h/500 outside the plane, or greater than 40mm;
9 The roof truss produces a deflection greater than 1m/250 or greater than 40mm; The roof truss support system is loose and unstable, resulting in the tilt of the roof truss, and the tilt exceeds h/150g
5 Building Danger Assessment
5.1 General Provisions
5.1.1 Dangerous houses (referred to as dangerous houses) are houses whose structures have been severely damaged, or whose load-bearing components have become dangerous components, which may lose stability and bearing capacity at any time and cannot ensure the safety of living and use. 5.1.2 The evaluation of the danger of houses should be carried out in accordance with the structural characteristics of the houses to be assessed and the types of load-bearing systems, according to their degree of danger and scope of influence, and in accordance with this standard.
5.1.3 Dangerous houses are assessed in units of buildings and measured by building area. 5.2 Classification
5.2.1 The house is divided into three parts: foundation, upper load-bearing structure and enclosure structure.
5.2.2 The hazard assessment of each part of the house shall be divided into the following levels:
Grade a: no dangerous points;
Grade 2b: dangerous points;
Grade 3c: local danger;
Grade 4d: overall danger.
5.2.3 The hazard assessment of the house shall be divided into the following levels; Grade 1A: The structural bearing capacity can meet the normal use requirements, no dangerous points are found, and the house structure is safe.
Grade 2B: The structural bearing capacity can basically meet the normal use requirements, and some structural components are in a dangerous state, but it does not affect the main structure and basically meets the normal use requirements.
Grade 3C: The bearing capacity of some load-bearing structures cannot meet the requirements of normal use, and local danger occurs, constituting a local dangerous building. Grade 4D: The bearing capacity of the load-bearing structure can no longer meet the requirements of normal use, and the entire house is in danger, constituting a dangerous building. 5.3 Principles of comprehensive assessment
5.3.1 The evaluation of the danger of a house should be based on the evaluation of the severity of the danger of the foundation and structural components of the entire house, combined with historical status, environmental impact and development trends, and a comprehensive analysis and comprehensive judgment. 5.3.2 In judging the danger of the foundation or structural components, it should be considered whether their dangers are isolated or related. When the danger of a component is isolated, it does not constitute a danger to the structural system; when the danger of a component is related, its scope should be determined in conjunction with the danger of the structure.
5.3.3 The following factors should be considered during comprehensive analysis and comprehensive judgment: 1 The degree of damage of each component:
2 The position of the damaged component in the whole building; The number and proportion of the damaged components in the whole building; 3
4 The impact of the overall surrounding environment of the structure;
5 Human factors and dangerous conditions that damage the structure; 6 The repairability of the structure after damage;
7 The economic losses caused by the damaged components.
5.4 Comprehensive evaluation method
5.4.1 According to the building components divided by this standard, determine the total amount of components and determine the number of dangerous components respectively. 5.4.2 The percentage of dangerous components in the foundation should be calculated according to the following formula: piedm = nd/n × 100%
Formula China
Percentage of dangerous components (dangerous points) in the foundation;
Number of dangerous components;
Number of components.
The percentage of dangerous components in the load-bearing structure shall be calculated as follows: 5.4.3
Pan [2.4nd. + 2.4ndw + 1.9(n dmh + ndn)+ 1.4ndsh + ndJ/2.4n.+ 2.4nw+ 1.9(nmb + n.) + 1.4nsb + ngl × 100%(5.4.3)
wherein Pxm
is the percentage of dangerous components (dangerous points) in the load-bearing structure:
number of dangerous columns;
number of dangerous wall sections;
-number of dangerous main beams:
-number of dangerous roof trusses;
-number of dangerous secondary beams;
number of dangerous slabs;
number of columns;
number of wall sections;
number of main beams:
number of roof trusses;
number of secondary beams;
number of slabs.
4 The percentage of dangerous components in the enclosure structure shall be calculated as follows: 5.4.4
pexlm = nid/n × 100%
wherein pesdm
percentage of dangerous components (dangerous points) in the enclosure structure;
number of dangerous components;
6—7—7
-number of components
5.4.5 The membership function of the a-level building component shall be calculated as follows: where
n = 1 (p= 0%)
the degree of membership of the a-level building component;
-the percentage of dangerous components (dangerous points), (5.4.5)
5.4.6 The membership function of the b-level building component shall be calculated as follows: (p≤5%)
(30% -p)/25% (5%9);
2 There are cracks or sharp-angle cuts in the components or connectors; welds, bolts or rivets are pulled apart, deformed, slipped, loosened, sheared and other serious damages:
3 Improper connection method and serious structural defects; 4 The cross-section of the tension member is reduced by more than 10% of the original cross-section due to rust;
45mm;
The deflection of beams, plates and other components is greater than Lo/250, or greater than 6. The lateral bending height of the solid web beam is greater than L0/600, and there are signs of development:
7 The slenderness ratio of the compression member is greater than the current national standard "Code for Design of Steel Structures" (GIBJ1788) 1.2 times the specified value: 8 Displacement of the top of the steel column, greater than h/150 in the plane, greater than h/500 outside the plane, or greater than 40mm;
9 The roof truss produces a deflection greater than 1m/250 or greater than 40mm; The roof truss support system is loose and unstable, causing the roof truss to tilt, and the tilt exceeds h/150g
5 Assessment of the danger of buildings
5.1 General provisions
5.1.1 Dangerous buildings (referred to as dangerous buildings) are buildings with serious structural damage, or load-bearing components that are already dangerous components, which may lose stability and bearing capacity at any time and cannot ensure safety for living and use. 5.1.2 The assessment of the danger of buildings should be carried out in accordance with the structural characteristics of the buildings to be assessed and the type of load-bearing system, according to their degree of danger and scope of influence, and in accordance with this standard.
5.1.3 Dangerous buildings are assessed in units of buildings and measured by building area. 5.2 Classification
5.2.1 The house is divided into three parts: foundation, upper load-bearing structure and enclosure structure.
5.2.2 The hazard assessment of each part of the house shall be divided into the following levels:
Grade a: no dangerous points;
Grade 2b: dangerous points;
Grade 3c: local danger;
Grade 4d: overall danger.
5.2.3 The hazard assessment of the house shall be divided into the following levels; Grade 1A: The structural bearing capacity can meet the normal use requirements, no dangerous points are found, and the house structure is safe.
Grade 2B: The structural bearing capacity can basically meet the normal use requirements, and some structural components are in a dangerous state, but it does not affect the main structure and basically meets the normal use requirements.
Grade 3C: The bearing capacity of some load-bearing structures cannot meet the requirements of normal use, and local danger occurs, constituting a local dangerous building. Grade 4D: The bearing capacity of the load-bearing structure can no longer meet the requirements of normal use, and the entire house is in danger, constituting a dangerous building. 5.3 Principles of comprehensive assessment
5.3.1 The evaluation of the danger of a house should be based on the evaluation of the severity of the danger of the foundation and structural components of the entire house, combined with historical status, environmental impact and development trends, and a comprehensive analysis and comprehensive judgment. 5.3.2 In judging the danger of the foundation or structural components, it should be considered whether their dangers are isolated or related. When the danger of a component is isolated, it does not constitute a danger to the structural system; when the danger of a component is related, its scope should be determined in conjunction with the danger of the structure.
5.3.3 The following factors should be considered during comprehensive analysis and comprehensive judgment: 1 The degree of damage of each component:
2 The position of the damaged component in the whole building; The number and proportion of the damaged components in the whole building; 3
4 The impact of the overall surrounding environment of the structure;
5 Human factors and dangerous conditions that damage the structure; 6 The repairability of the structure after damage;
7 The economic losses caused by the damaged components.
5.4 Comprehensive evaluation method
5.4.1 According to the building components divided by this standard, determine the total amount of components and determine the number of dangerous components respectively. 5.4.2 The percentage of dangerous components in the foundation should be calculated according to the following formula: piedm = nd/n × 100%
Formula China
Percentage of dangerous components (dangerous points) in the foundation;
Number of dangerous components;
Number of components.
The percentage of dangerous components in the load-bearing structure shall be calculated as follows: 5.4.3
Pan [2.4nd. + 2.4ndw + 1.9(n dmh + ndn)+ 1.4ndsh + ndJ/2.4n.+ 2.4nw+ 1.9(nmb + n.) + 1.4nsb + ngl × 100%(5.4.3)
wherein Pxm
is the percentage of dangerous components (dangerous points) in the load-bearing structure:
number of dangerous columns;
number of dangerous wall sections;
-number of dangerous main beams:
-number of dangerous roof trusses;
-number of dangerous secondary beams;
number of dangerous slabs;
number of columns;
number of wall sections;
number of main beams:
number of roof trusses;
number of secondary beams;
number of slabs.
4 The percentage of dangerous components in the enclosure structure shall be calculated as follows: 5.4.4
pexlm = nid/n × 100%
wherein pesdm
percentage of dangerous components (dangerous points) in the enclosure structure;
number of dangerous components;
6—7—7
-number of components
5.4.5 The membership function of the a-level building component shall be calculated as follows: where
n = 1 (p= 0%)
the degree of membership of the a-level building component;
-the percentage of dangerous components (dangerous points), (5.4.5)
5.4.6 The membership function of the b-level building component shall be calculated as follows: (p≤5%)
(30% -p)/25% (5%9);
2 There are cracks or sharp-angle cuts in the components or connectors; welds, bolts or rivets are pulled apart, deformed, slipped, loosened, sheared and other serious damages:
3 Improper connection method and serious structural defects; 4 The cross-section of the tension member is reduced by more than 10% of the original cross-section due to rust;
45mm;
The deflection of beams, plates and other components is greater than Lo/250, or greater than 6. The lateral bending height of the solid web beam is greater than L0/600, and there are signs of development:
7 The slenderness ratio of the compression member is greater than the current national standard "Code for Design of Steel Structures" (GIBJ1788) 1.2 times the specified value: 8 Displacement of the top of the steel column, greater than h/150 in the plane, greater than h/500 outside the plane, or greater than 40mm;
9 The roof truss produces a deflection greater than 1m/250 or greater than 40mm; The roof truss support system is loose and unstable, causing the roof truss to tilt, and the tilt exceeds h/150g
5 Assessment of the danger of buildings
5.1 General provisions
5.1.1 Dangerous buildings (referred to as dangerous buildings) are buildings with serious structural damage, or load-bearing components that are already dangerous components, which may lose stability and bearing capacity at any time and cannot ensure safety for living and use. 5.1.2 The assessment of the danger of buildings should be carried out in accordance with the structural characteristics of the buildings to be assessed and the type of load-bearing system, according to their degree of danger and scope of influence, and in accordance with this standard.
5.1.3 Dangerous buildings are assessed in units of buildings and measured by building area. 5.2 Classification
5.2.1 The house is divided into three parts: foundation, upper load-bearing structure and enclosure structure.
5.2.2 The hazard assessment of each part of the house shall be divided into the following levels:
Grade a: no dangerous points;
Grade 2b: dangerous points;
Grade 3c: local danger;
Grade 4d: overall danger.
5.2.3 The hazard assessment of the house shall be divided into the following levels; Grade 1A: The structural bearing capacity can meet the normal use requirements, no dangerous points are found, and the house structure is safe.
Grade 2B: The structural bearing capacity can basically meet the normal use requirements, and some structural components are in a dangerous state, but it does not affect the main structure and basically meets the normal use requirements.
Grade 3C: The bearing capacity of some load-bearing structures cannot meet the requirements of normal use, and local danger occurs, constituting a local dangerous building. Grade 4D: The bearing capacity of the load-bearing structure can no longer meet the requirements of normal use, and the entire house is in danger, constituting a dangerous building. 5.3 Principles of comprehensive assessment
5.3.1 The evaluation of the danger of a house should be based on the evaluation of the severity of the danger of the foundation and structural components of the entire house, combined with historical status, environmental impact and development trends, and a comprehensive analysis and comprehensive judgment. 5.3.2 In judging the danger of the foundation or structural components, it should be considered whether their dangers are isolated or related. When the danger of a component is isolated, it does not constitute a danger to the structural system; when the danger of a component is related, its scope should be determined in conjunction with the danger of the structure.
5.3.3 The following factors should be considered during comprehensive analysis and comprehensive judgment: 1 The degree of damage of each component:
2 The position of the damaged component in the whole building; The number and proportion of the damaged components in the whole building; 3
4 The impact of the overall surrounding environment of the structure;
5 Human factors and dangerous conditions that damage the structure; 6 The repairability of the structure after damage;
7 The economic losses caused by the damaged components.
5.4 Comprehensive evaluation method
5.4.1 According to the building components divided by this standard, determine the total amount of components and determine the number of dangerous components respectively. 5.4.2 The percentage of dangerous components in the foundation should be calculated according to the following formula: piedm = nd/n × 100%
Formula China
Percentage of dangerous components (dangerous points) in the foundation;
Number of dangerous components;
Number of components.
The percentage of dangerous components in the load-bearing structure shall be calculated as follows: 5.4.3
Pan [2.4nd. + 2.4ndw + 1.9(n dmh + ndn)+ 1.4ndsh + ndJ/2.4n.+ 2.4nw+ 1.9(nmb + n.) + 1.4nsb + ngl × 100%(5.4.3)
wherein Pxm
is the percentage of dangerous components (dangerous points) in the load-bearing structure:
number of dangerous columns;
number of dangerous wall sections;
-number of dangerous main beams:
-number of dangerous roof trusses;
-number of dangerous secondary beams;
number of dangerous slabs;
number of columns;
number of wall sections;
number of main beams:
number of roof trusses;
number of secondary beams;
number of slabs.
4 The percentage of dangerous components in the enclosure structure shall be calculated as follows: 5.4.4
pexlm = nid/n × 100%
wherein pesdm
percentage of dangerous components (dangerous points) in the enclosure structure;
number of dangerous components;
6—7—7
-number of components
5.4.5 The membership function of the a-level building component shall be calculated as follows: where
n = 1 (p= 0%)
the degree of membership of the a-level building component;
-the percentage of dangerous components (dangerous points), (5.4.5)
5.4.6 The membership function of the b-level building component shall be calculated as follows: (p≤5%)
(30% -p)/25% (5%1 According to the building components divided in this standard, determine the total number of components and the number of dangerous components respectively. 5.4.2 The percentage of dangerous components in the foundation should be calculated according to the following formula: piedm = nd/n × 100%
Formula China
Percentage of dangerous components (dangerous points) in the foundation;
Number of dangerous components;
Number of components.
The percentage of dangerous components in the load-bearing structure should be calculated according to the following formula: 5.4.3
Pan [2.4nd. + 2.4ndw + 1.9(n dmh + ndn)+ 1.4ndsh + ndJ/2.4n.+ 2.4nw+ 1.9(nmb + n.) + 1.4nsb + ngl × 100%(5.4.3)
wherein Pxm
is the percentage of dangerous components (dangerous points) in the load-bearing structure:
number of dangerous columns;
number of dangerous wall sections;
-number of dangerous main beams:
-number of dangerous roof trusses;
-number of dangerous secondary beams;
number of dangerous slabs;
number of columns;
number of wall sections;
number of main beams:
number of roof trusses;
number of secondary beams;
number of slabs.
4 The percentage of dangerous components in the enclosure structure shall be calculated as follows: 5.4.4
pexlm = nid/n × 100%
wherein pesdm
percentage of dangerous components (dangerous points) in the enclosure structure;
number of dangerous components;
6—7—7
-number of components
5.4.5 The membership function of the a-level building component shall be calculated as follows: where
n = 1 (p= 0%)
the degree of membership of the a-level building component;
-the percentage of dangerous components (dangerous points), (5.4.5)
5.4.6 The membership function of the b-level building component shall be calculated as follows: (p≤5%)
(30% -p)/25% (5%1 According to the building components divided in this standard, determine the total number of components and the number of dangerous components respectively. 5.4.2 The percentage of dangerous components in the foundation should be calculated according to the following formula: piedm = nd/n × 100%
Formula China
Percentage of dangerous components (dangerous points) in the foundation;
Number of dangerous components;
Number of components.
The percentage of dangerous components in the load-bearing structure should be calculated according to the following formula: 5.4.3
Pan [2.4nd. + 2.4ndw + 1.9(n dmh + ndn)+ 1.4ndsh + ndJ/2.4n.+ 2.4nw+ 1.9(nmb + n.) + 1.4nsb + ngl × 100%(5.4.3)
wherein Pxm
is the percentage of dangerous components (dangerous points) in the load-bearing structure:
number of dangerous columns;
number of dangerous wall sections;
-number of dangerous main beams:
-number of dangerous roof trusses;
-number of dangerous secondary beams;
number of dangerous slabs;
number of columns;
number of wall sections;
number of main beams:
number of roof trusses;
number of secondary beams;
number of slabs.
4 The percentage of dangerous components in the enclosure structure shall be calculated as follows: 5.4.4
pexlm = nid/n × 100%
wherein pesdm
percentage of dangerous components (dangerous points) in the enclosure structure;
number of dangerous components;
6—7—7
-number of components
5.4.5 The membership function of the a-level building component shall be calculated as follows: where
n = 1 (p= 0%)
the degree of membership of the a-level building component;
-the percentage of dangerous components (dangerous points), (5.4.5)
5.4.6 The membership function of the b-level building component shall be calculated as follows: (p≤5%)
(30% -p)/25% (5%
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