1.0.1 This code is formulated in order to make the design and construction of fired perforated brick masonry structure implemented of the technical and economic policy of energy saving and land conservation, relieve earthquake damage to buildings and achieve advanced technology, economic feasibility, safety and usability and guaranteed quality.
1.0.2 This code is applicable to the design and acceptance of the masonry structures with P-type fired perforated brick and M-type modulus fired perforated brick (hereinafter referred to as perforated brick ) as wall materials in non-seismic fortification area and areas with seismic fortification intensity of Intensity 6 to Intensity 9..
1.0.3 In the design, construction and acceptance of perforated brick masonry structure, not only this code but also the requirements of current related compulsory standard of the nation shall be complied with.
2 Terms and Symbols
2.1 Terms
2.1.1 Fired perforated brick
It is fired from the main raw materials of clay soil, shale and coal gangue. Its void ratio is not less than and hole form is circular hole or non circular hole. Size of the hole is small but there are many holes. It is mainly applicable to the brick at bearing parts, for short perforated brick. At the present, perforated brick is divided into P-type brick and M-type brick.
2.1.2 P-type perforated brick
It refers to the brick whose overall dimension is 240mrn× 115mm× 90mm, for short P-type brick.
2.1.3 M-type modulus perforated brick
It refers to the brick whose overall dimension is 190mm× 190mm× 90mm, for short M-type brick.
2.1.4 Auxiliary brick
It refers to the brick used in conjunction with main specification brick in mason, such as half brick, 7/10 brick and M-type series of matched brick etc.
2.1.5 Supporting floor loading formwork
It is one of construction practice for cast-in-place ring beam in multi-storey masonry building. The concrete operations are: on the wall built to elevation of the ring beam bottom, supporting formwork, banding ring beam reinforcement bar, paving floor and roof board (temporarily roof board loading is supported by formwork), banding the tendon extended from the end of precast slab and casing concrete in ring beam.
2.2 Symbols
2.2.1 Action and action effect
FEk - standard value of the total horizontal earthquake action of structure;
F- Design value of concentrated force;
GE - Representative value of gravity load
Gk - Stand value of permanent load of structural members and accessories;
Gki -Standard value of variable load;
Geq - Representative value of equivalent total gravity load of structures (members) in earthquake;
N- Design value of axial force;
Nk - Standard value of axial force;
Nu - Design value of upper axial force;
V- Design value of shear force;
σ0- Mean compression stress of masonry section corresponding to the representative value of the gravity load.
γ- Gravity density
2.2.2 Material property and resisting force
C- Concrete strength grade;
E- Elastic modulus of the masonry;
f1- Average value of compression strength of the perforated brick;
f- Design value of compression strength of the masonry;
fd -Design value of strength of the masonry;
fk -Standard value of strength of the masonry;
fm - Average value of strength of the masonry;
ftm - Design value of tensile strength for crook of the masonry;
ftm, k- Standard value of tensile strength for crook of the masonry;
f2 - Average value of compression strength of the mortar;
f2m - Average value of compression strength of the mortar in the same acceptance lot;
f2min - Average value of a group of mortar with minimum compression strength;
fVE - Design value of the seismic shear strength of the damaged masonry along the stepped cross section;
fV - Design value of shear strength of the masonry;
G- Shear modulus of the masonry;
MU - Intensity grade of the perforated brick;
M- Mortar strength grade.
2.2.3 Geometric parameters
A- Gross sectional area of the perforated brick masonry;
a0- Effective supporting length of beam end;
a- Actual supporting length of side length and beam end;
b- Section width, side length;
bf - Calculated section flange width with pilaster , calculated width of the flange;
bs - Opening width of doors and windows within the distance range between adjacent cross walls or pilasters;
c, d - Distance, diameter;
e- Eccentricity;
e0- Additional eccentricity;
H- Height of members;
H0- Calculated height of members;
h- Thickness of the wall or side length, depth of the beam in eccentric direction of longitudinal force of rectangular section;
hc -Sectional depth of the beam;
hT - Reduced thickness of T section;
i - Gyration radium of the section;
q- Void ratio;
s - Distance between adjacent cross walls or pilasters;
y - Distance from centroid of section to edges of the section in the located direction of axial force.
γf - Partial coefficient for material property of structural members;
μ1 - Correction coefficient for the allowable ratio of height to thickness of non bearing wall;
μ2 - Correction coefficient for the allowable ratio of height and thickness of the wall with door and window openings;
β - Ratio of height to thickness of members;
[β] - Allowable ratio of height to thickness of the wall and column;
γEh - Partial coefficient for the horizontal earthquake action;
γRE - Seismic adjustment coefficient of bearing capacity;
ΨEi - Combination value coefficient of the variable load;
αmax - The maximum value of horizontal seismic influence coefficient;
ζN - Normal stress influence coefficient of masonry strength;
ηk - Hole effect reduction coefficient of the perforated brick masonry.
3 Index of Computation for Materials and Masonry
3.0.1 Intensity level of perforated brick and masonry mortar shall be adopted according to the following requirements:
1 Intensity level of the perforated brick: MU 30, MU 25, MU20, MU15 and MU 1010:
2 Intensity level of the masonry mortar: M15, M10, M7.5, M5 and M2.5.
Note: In determination of mortar strength grade, side surface of the same kind of perforated brick shall be adopted for bottom die of test specimen for mortar strength.
3.0.2 Their age is 28d; as for the design value of compression strength of perforated brick masonry whose age is 28 and calculated in gross sectional area, when the level of construction quality control is Level B, shall be aopted based on the intensity level of the perforated brick and mortar according to Table 3.0.2; when the void ratio of the perforated brick is larger than 30％, it shall be adopted after the values in Table multiply 0.9.
Table 3.0.2 Design value of compression strength of the perforated brick masonry (MPa)
Foreword I 1 General Provisions 2 Terms and Symbols 2.1 Terms 2.2 Symbols 3 Index of Computation for Materials and Masonry 4 Static Design 4.1 Basic Requirements on Design 4.2 Calculation of Load-bearing Capacity for Compression Members 4.3 Allowable Ratio of Height to Thickness of Walls and Columns 4.4 General Construction Requirements 4.5 Ring Beam and Lintel 4.6 Measures for Preventing and Alleviating Crack of Walls 5 Seismic Design 5.1 General Requirement 5.2 Checking Calculation of Earthquake Action and Seismic Bearing Capacity 5.3 Seismic Structural Measures 6 Construction and Quality Inspection 6.1 Construction Preparation 6.2 Construction Technology Requirements 6.3 Safety Measures 6.4 Engineering Quality Inspection 6.5 Project Acceptance Appendix A Influence coefficient ψ of axial force Explanation of Wording
1 General Provisions
1.0.1 This code is formulated in order to make the design and construction of fired perforated brick masonry structure implemented of the technical and economic policy of energy saving and land conservation, relieve earthquake damage to buildings and achieve advanced technology, economic feasibility, safety and usability and guaranteed quality.
1.0.2 This code is applicable to the design and acceptance of the masonry structures with P-type fired perforated brick and M-type modulus fired perforated brick (hereinafter referred to as perforated brick ) as wall materials in non-seismic fortification area and areas with seismic fortification intensity of Intensity 6 to Intensity 9..
1.0.3 In the design, construction and acceptance of perforated brick masonry structure, not only this code but also the requirements of current related compulsory standard of the nation shall be complied with.
2 Terms and Symbols
2.1 Terms
2.1.1 Fired perforated brick
It is fired from the main raw materials of clay soil, shale and coal gangue. Its void ratio is not less than and hole form is circular hole or non circular hole. Size of the hole is small but there are many holes. It is mainly applicable to the brick at bearing parts, for short perforated brick. At the present, perforated brick is divided into P-type brick and M-type brick.
2.1.2 P-type perforated brick
It refers to the brick whose overall dimension is 240mrn× 115mm× 90mm, for short P-type brick.
2.1.3 M-type modulus perforated brick
It refers to the brick whose overall dimension is 190mm× 190mm× 90mm, for short M-type brick.
2.1.4 Auxiliary brick
It refers to the brick used in conjunction with main specification brick in mason, such as half brick, 7/10 brick and M-type series of matched brick etc.
2.1.5 Supporting floor loading formwork
It is one of construction practice for cast-in-place ring beam in multi-storey masonry building. The concrete operations are: on the wall built to elevation of the ring beam bottom, supporting formwork, banding ring beam reinforcement bar, paving floor and roof board (temporarily roof board loading is supported by formwork), banding the tendon extended from the end of precast slab and casing concrete in ring beam.
2.2 Symbols
2.2.1 Action and action effect
FEk - standard value of the total horizontal earthquake action of structure;
F- Design value of concentrated force;
GE - Representative value of gravity load
Gk - Stand value of permanent load of structural members and accessories;
Gki -Standard value of variable load;
Geq - Representative value of equivalent total gravity load of structures (members) in earthquake;
N- Design value of axial force;
Nk - Standard value of axial force;
Nu - Design value of upper axial force;
V- Design value of shear force;
σ0- Mean compression stress of masonry section corresponding to the representative value of the gravity load.
γ- Gravity density
2.2.2 Material property and resisting force
C- Concrete strength grade;
E- Elastic modulus of the masonry;
f1- Average value of compression strength of the perforated brick;
f- Design value of compression strength of the masonry;
fd -Design value of strength of the masonry;
fk -Standard value of strength of the masonry;
fm - Average value of strength of the masonry;
ftm - Design value of tensile strength for crook of the masonry;
ftm, k- Standard value of tensile strength for crook of the masonry;
f2 - Average value of compression strength of the mortar;
f2m - Average value of compression strength of the mortar in the same acceptance lot;
f2min - Average value of a group of mortar with minimum compression strength;
fVE - Design value of the seismic shear strength of the damaged masonry along the stepped cross section;
fV - Design value of shear strength of the masonry;
G- Shear modulus of the masonry;
MU - Intensity grade of the perforated brick;
M- Mortar strength grade.
2.2.3 Geometric parameters
A- Gross sectional area of the perforated brick masonry;
a0- Effective supporting length of beam end;
a- Actual supporting length of side length and beam end;
b- Section width, side length;
bf - Calculated section flange width with pilaster , calculated width of the flange;
bs - Opening width of doors and windows within the distance range between adjacent cross walls or pilasters;
c, d - Distance, diameter;
e- Eccentricity;
e0- Additional eccentricity;
H- Height of members;
H0- Calculated height of members;
h- Thickness of the wall or side length, depth of the beam in eccentric direction of longitudinal force of rectangular section;
hc -Sectional depth of the beam;
hT - Reduced thickness of T section;
i - Gyration radium of the section;
q- Void ratio;
s - Distance between adjacent cross walls or pilasters;
y - Distance from centroid of section to edges of the section in the located direction of axial force.
2.2.4 Calculated coefficient
CEh - Horizontal earthquake action effect coefficient;
γa - Adjustment coefficient;
Ψ - Influence coefficient of the axial force;
Ψ0 - Axial compression stability coefficient;
Ψ - Reduction coefficient;
γ0 - Significance coefficient of structures;
γf - Partial coefficient for material property of structural members;
μ1 - Correction coefficient for the allowable ratio of height to thickness of non bearing wall;
μ2 - Correction coefficient for the allowable ratio of height and thickness of the wall with door and window openings;
β - Ratio of height to thickness of members;
[β] - Allowable ratio of height to thickness of the wall and column;
γEh - Partial coefficient for the horizontal earthquake action;
γRE - Seismic adjustment coefficient of bearing capacity;
ΨEi - Combination value coefficient of the variable load;
αmax - The maximum value of horizontal seismic influence coefficient;
ζN - Normal stress influence coefficient of masonry strength;
ηk - Hole effect reduction coefficient of the perforated brick masonry.
3 Index of Computation for Materials and Masonry
3.0.1 Intensity level of perforated brick and masonry mortar shall be adopted according to the following requirements:
1 Intensity level of the perforated brick: MU 30, MU 25, MU20, MU15 and MU 1010:
2 Intensity level of the masonry mortar: M15, M10, M7.5, M5 and M2.5.
Note: In determination of mortar strength grade, side surface of the same kind of perforated brick shall be adopted for bottom die of test specimen for mortar strength.
3.0.2 Their age is 28d; as for the design value of compression strength of perforated brick masonry whose age is 28 and calculated in gross sectional area, when the level of construction quality control is Level B, shall be aopted based on the intensity level of the perforated brick and mortar according to Table 3.0.2; when the void ratio of the perforated brick is larger than 30％, it shall be adopted after the values in Table multiply 0.9.
Table 3.0.2 Design value of compression strength of the perforated brick masonry (MPa)
Contents of JGJ 137-2001(2002)
Foreword I
1 General Provisions
2 Terms and Symbols
2.1 Terms
2.2 Symbols
3 Index of Computation for Materials and Masonry
4 Static Design
4.1 Basic Requirements on Design
4.2 Calculation of Load-bearing Capacity for Compression Members
4.3 Allowable Ratio of Height to Thickness of Walls and Columns
4.4 General Construction Requirements
4.5 Ring Beam and Lintel
4.6 Measures for Preventing and Alleviating Crack of Walls
5 Seismic Design
5.1 General Requirement
5.2 Checking Calculation of Earthquake Action and Seismic Bearing Capacity
5.3 Seismic Structural Measures
6 Construction and Quality Inspection
6.1 Construction Preparation
6.2 Construction Technology Requirements
6.3 Safety Measures
6.4 Engineering Quality Inspection
6.5 Project Acceptance
Appendix A Influence coefficient ψ of axial force
Explanation of Wording
