Back bolt connection granite curtain wall
one. Overview
With the back bolt point to connect the granite curtain wall for building exterior granite construction is the construction of the exterior surface of a major breakthrough in construction technology, it opened a stone curtain wall construction technology to avoid a new era. So that the stone curtain wall has a broad field of use, that any building, any height, any part of any form of structure can be used to connect the granite back bolt point curtain wall. Back bolt The back bolt connecting the granite curtain wall is only used as the fastener of the stone plate and the connecting piece, so that the connecting piece can be designed flexibly according to the need, and the steel pin, short groove type, ) And the beam (column) connection, and stone and the connection, its use of parts and methods with very limited, back bolt connection method for the stone curtain wall and glass (metal) curtain wall combination to create a combination of curtain wall conditions, In the same column on the left to install the glass curtain wall, the right to install stone walls, in the same beam, can be installed above the glass curtain wall, below the installation of stone walls.
Back bolt point granite curtain wall has been connected for more than 20 years of history, China in the nineteen twentieth century began to use. Built in 1998, the Bank of China Tower (Pudong International Finance Tower) is a high-rise building with 235m height and 139m below. The granite curtain wall is covered with a back-bolt connection. The surface of the main structure is covered with 15000m2 granite curtain wall. (H × B) 2.05m × 0.3m, the highest point of the granite curtain wall is 139m. The size of granite is (H × B) 2.05m × 0.3m, and the highest point of granite curtain wall is 139m. In 1999, the cross-point connection of granite curtain wall was up to 196m. There are still many projects in China which use the back bolt to connect the granite curtain wall. The total amount is more than 1 million m2.
"Practice is the sole criterion for testing the truth." In the construction of these walls, in addition to the usual wind pressure deformation, air infiltration, rain water leakage of the three physical properties of testing, but also on the back bolt and back bolt anchor stone connection parts (8500h) static load shear, tensile test, back bolt anchoring fatigue test, as well as the back bolt connection granite curtain wall of the back bolt test, the back bolt bolt anchor test, Seismic performance of shaking table test, accumulated a large number of test parameters, proved that the back bolt point granite curtain wall has a high reliability, and to find out the direction of local structural improvement. This is discussed in detail below:
1. Back bolt bolt tensile test. According to the survey data, the material of back bolt is similar to that of A2-70 stainless steel bolt, its ultimate tensile strength is close to 700N / mm2, non-proportional elongation stress is greater than 480N / mm2, a φ12mm (φ8mm, φ6mm) The area of 84.3mm2 (36.6mm2, 20.1mm2), the ultimate tensile strength of 59KN (25.6KN, 14KN) is back bolt anchor stone pulling force of 2.5 times to 10 times, that back bolt bolt will only be Stone punching damage, so as long as the selection of the steel bolt on the back bolt on the line.
Tensile pull test on the back bolt of the test results of mathematical statistics, should be GB50068 Article 5.0.3 provisions to take fk = μf-1.645σf, bolt bolt tensile strength design value according to GB50017 desirable ftb = fub / 2.174, shear strength The design value fvb = fub / 2.857.
Now some manufacturers to provide the parameters, take fk = uf-2.57σf. And tensile material sub-coefficient of 1.8, and the shear coefficient of 3.2 and GB50068 and GB50017 inconsistent, GB50068 Article 1.0.3 provides: "to develop the structure Load specifications and steel structure design specifications, such as ----- should comply with the provisions of this specification. My personal opinion or by GB50068 implementation.
2. Anchor bearing resistance to pull-carrying capacity test,
From the test situation to see the back bolt and stone anchor all the stone punching damage, damage to the state of stone taper damage, the impact of damage factors are back bolt diameter, back bolt bolt depth, the strength of the stone itself, in which the most direct impact of anchor depth, And when the anchor depth is equal to less than 12mm, the carrying capacity of the disruption of the larger, the regression statistics, anti-tensile load-bearing capacity of the anchor by the depth of 1.5 index growth, the substrate strength against the load carrying capacity of 0.5 growth index, 6mm back Bearing capacity of 4.5KN ~ 8KN, φ8mm back bolt anti-drawing bearing capacity of 5KN ~ 10KN, φ12mm back bolt anti-pull carrying capacity of 6KN ~ 12KN.
Above the standard value of the carrying capacity, the test results will pull out the mathematical statistics, the average minus 1.645 times the standard deviation, the anchor depth ≤ 12mm larger discrepancies, the standard deviation is also large, according to fK = μf-1.645σf The discretization has been taken into account and no further reduction of the coefficient is necessary. Its design value fTV = fK / 2.143 / 2. The bending strength of the stone can be calculated by the engineering stress method only when the stone is subjected to compression (bending) test:
Τ = P / [π * h / cosα * (D + h * tanα)] ≦ fT
3, anchor long-term static load test
(8500H). The tests are divided into long-term static load test and pull-out test. The results show that the tensile strength of the back anchor is different from that of the anchor. , Shear test refers to the bolt in the load under the shear load by 8500H, the tensile test specimen to do the ultimate pullout test and the long-term load test specimens for comparison, the test results show good shear resistance, No damage or displacement was observed in the long-term pull-out test, except that the assembly gap displacement (≤0.3mm) was not observed during the initial loading period.
Indicating that the connection between the back bolt and the stone is very reliable even under long-term external load.
4, the anchor load of the anchor fatigue test, that is repeated fatigue test load.
In the positive pressure 3 million + negative pressure 3 million times the reciprocating dynamic load fatigue resistance test, with nylon plastic sleeve back bolt in the bolt and the hole between the three-way isolation effect of shock isolation, under impact The single-section back bolt can not be damaged or moved obviously due to the back bolt's own activities and the pressure and pull action of the reciprocating motive force in the multi-million times strong reciprocating dynamic load fatigue test. , The worst in the 126 negative pressure damage, it can be seen with the best back bolt nylon sleeve, and the use of double-cross-section of the back bolt and stone to be the first fastening.
5, seismic testing
China Academy of Building Research, China Academy of Water Sciences for a number of stone curtain wall seismic performance shaking table test. Test results show that the earthquake acceleration 0.6g or less (equivalent to the intensity of 9.7 degrees) when everything is normal, South China Institute of Urban Earthquake Center test found in 0.6g when the back bolt has loosening signs, 0.8g (equivalent to 10 degrees) curtain wall Hook is out of the beam may be analyzed by the main bolt hole is not required by the processing requirements, the use of single-sided non-nylon mattress back bolt, curtain wall components hook and beam lap less than 6mm. Other tests used a double-face nylon bolt with a back bolt, curtain wall unit component hook and beam lap height greater than 10mm, even at 0.9g (equivalent to 10.2 degrees of intensity), the inter-layer displacement of 1/54, the back The connection between granite curtain walls remains intact, and the anti-pull ability of stone bolts and stone anchors in the specimens subjected to seismic tests is almost the same as that of the specimens without earthquake resistance test.
It can be seen from the above test, back bolt type granite curtain wall connection in the specification of the use of the range (6-8 degrees area), can be used without nylon plastic sleeve single-sided back bolt, when used for 9 degrees And 9 degrees above the intensity of the area, should be used with nylon plastic sleeve sets of double-section back bolt. The height of the lap joint between the curtain wall component and the beam should not be less than 10mm.
Second, design and calculation
1, structural design
First of all, to establish a concept: the back bolt is a fastener, which stone and stone curtain wall components in the link together, it is
In the freely removable fastener, the connecting member may be designed as desired in accordance with the construction requirements of the glass (metal) curtain wall in each curtain wall which is combined with the stone curtain wall. For example, and extrapolation hidden curtain wall (small unit curtain wall) can be used in combination with the plug-in matching connector, with the back bolt to the stone fixed on the extrapolation of the box.
Stone and connecting pieces of connection, depending on stone size and construction requirements can be used a back bolt, two back bolt, four back bolt and so on.
When using a back bolt, the hole should generally be located in the center of the board, the hole to the edge of the board is not greater than 300mm, plates and connectors should also use 4 nylon bolts to withstand the inside of the board to keep the board stable.
When using two back bolts, the hole in the top edge of the board to the distance of not more than 400mm, to the side is not greater than 300mm, both sides of the back bolt with nylon bolts to withstand the inside of the plate to keep the plate stable.
When using four bolts, the hole in the board edge distance of not more than 250mm.
Back bolt and hole construction requirements are as follows:
Table 1
Type Drilling diameter Anchor depth Connection bolt Maximum anchorage thickness Bottom hole diameter Minimum plate thickness
FZP 11 × 12M6 / 3A4 11 12 M6 3 13.5 20
FZP11 x 12M6 / 9A4 11 12 M6 9 13.5 20
FZP 11 × 15M6 / 6A4 11 15 M6 6 13.5 28
FZP 13 × 15M8 / 4A4 13 15 M8 4 15.5 28
FZP 13 × 15M8 / 25A4 13 15 M8 25 15.5 35
FZP13 × 20M8 / 10A4 13 20 M8 10 15.5 35
FZP13 × 21M8w / 5A4 13 21 M8 5 15.5 35
FZP13 × 21M8w / 20A4 13 21 M8 20 15.5 35
FZP 11 × 19M6 / 6kt / 3AL 11 10 ~ 14 M6 3 13.5 20
FZP 11 × 21M6 / 6kt / 4AL 11 12 ~ 16 M6 4 13.5 20
FZP13 × 24M6 / 6kt / 3AL 13 15~19 M8 3 15.5 30
FZP 13 × 26M8 / 6kt / 5AL 13 17~21 M8 5 15.5 34
FZP 11 × 21M6 / ES / 4AL 11 12 to 16 M6 4 13.5 20
FZP 13 × 24M8 / ES / 4AL 13 15~19 M8 4 15.5 30
Back bolt and stone anchor parts of the construction quality is an important part of the limit (tolerance) with the determination and testing requirements hole deviation
± 0.5mm, hole deviation ± 0.5mm, hole distance and hole deviation of not more than ± 1.0mm, aperture (φ6 ~ 8mm) +0.4 mm, -0.2mm,
Hole depth + 0.4mm, -0.1mm, the bottom hole diameter of ± 0.3mm.
2. Design calculations
A. One plate with a back bolt
P = qA
(0.64 L / t) +1.062] ≤ fT or σ = (P / t2) * [0.5563Ln (0.64L / t)
U = C x (P x L2 / E x t3)
Table 2
LX / LY (LY / LX) C
1.0 0.1265
1.1 0.1381
1.2 0.1478
1.4 0.1621
1.6 0.1714
1.8 0.1769
2.0 0.1803
3.0 0.184
∞ 0.1849
Τ = P / [π * h / cosα * (D + h * tanα)]
Where: L - LX, Ly the smaller (mm); t - thickness (mm);
D - anchor hole diameter (mm); h - anchor hole depth (mm).
B. One plate is anchored with two back bolts, which can be simplified as simply supported plates with cantilever at both ends
MA = MB = -qa2 / 2
R = qL / 2
Mφ = qL2 / 8 × 1 - 4 × a / L 2 -
(A / L) 2 + 3 (a / L) 3] uC = uD = qaL2 / 24EI [
Uφ = qL4 / 384EI [5-24 (a / L) 2]
Τ = R / [π * h / cosα * (D + h * tanα)]
C. One plate is anchored with four back bolts and is calculated as a quadrangular support plate
Σ = 6mqL2 / t2
Where: L - LX, Ly in the larger;
M - bending moment coefficient.
Τ = (qa / 4 * 1.25) / [π * h / cosα * (D + h * tanα)]
Table 3 Bending moment coefficient table
LX / LY m
0.50 0.1304
0.55 0.1320
0.60 0.1339
0.65 0.1361
0.70 0.1384
0.75
0.80 0.1435
0.85 0.1464
0.90 0.1494
0.95 0.1526
1.00 0.1559
Table 4 Natural granite slab strength classification table N / mm2 t
Grade strength Standard value Design value of flexural strength fr Shear strength design value ftv Elastic modulus
With the back bolt point to connect the granite curtain wall for building exterior granite construction is the construction of the exterior surface of a major breakthrough in construction technology, it opened a stone curtain wall construction technology to avoid a new era. So that the stone curtain wall has a broad field of use, that any building, any height, any part of any form of structure can be used to connect the granite back bolt point curtain wall. Back bolt The back bolt connecting the granite curtain wall is only used as the fastener of the stone plate and the connecting piece, so that the connecting piece can be designed flexibly according to the need, and the steel pin, short groove type, ) And the beam (column) connection, and stone and the connection, its use of parts and methods with very limited, back bolt connection method for the stone curtain wall and glass (metal) curtain wall combination to create a combination of curtain wall conditions, In the same column on the left to install the glass curtain wall, the right to install stone walls, in the same beam, can be installed above the glass curtain wall, below the installation of stone walls.
Back bolt point granite curtain wall has been connected for more than 20 years of history, China in the nineteen twentieth century began to use. Built in 1998, the Bank of China Tower (Pudong International Finance Tower) is a high-rise building with 235m height and 139m below. The granite curtain wall is covered with a back-bolt connection. The surface of the main structure is covered with 15000m2 granite curtain wall. (H × B) 2.05m × 0.3m, the highest point of the granite curtain wall is 139m. The size of granite is (H × B) 2.05m × 0.3m, and the highest point of granite curtain wall is 139m. In 1999, the cross-point connection of granite curtain wall was up to 196m. There are still many projects in China which use the back bolt to connect the granite curtain wall. The total amount is more than 1 million m2.
"Practice is the sole criterion for testing the truth." In the construction of these walls, in addition to the usual wind pressure deformation, air infiltration, rain water leakage of the three physical properties of testing, but also on the back bolt and back bolt anchor stone connection parts (8500h) static load shear, tensile test, back bolt anchoring fatigue test, as well as the back bolt connection granite curtain wall of the back bolt test, the back bolt bolt anchor test, Seismic performance of shaking table test, accumulated a large number of test parameters, proved that the back bolt point granite curtain wall has a high reliability, and to find out the direction of local structural improvement. This is discussed in detail below:
1. Back bolt bolt tensile test. According to the survey data, the material of back bolt is similar to that of A2-70 stainless steel bolt, its ultimate tensile strength is close to 700N / mm2, non-proportional elongation stress is greater than 480N / mm2, a φ12mm (φ8mm, φ6mm) The area of 84.3mm2 (36.6mm2, 20.1mm2), the ultimate tensile strength of 59KN (25.6KN, 14KN) is back bolt anchor stone pulling force of 2.5 times to 10 times, that back bolt bolt will only be Stone punching damage, so as long as the selection of the steel bolt on the back bolt on the line.
Tensile pull test on the back bolt of the test results of mathematical statistics, should be GB50068 Article 5.0.3 provisions to take fk = μf-1.645σf, bolt bolt tensile strength design value according to GB50017 desirable ftb = fub / 2.174, shear strength The design value fvb = fub / 2.857.
Now some manufacturers to provide the parameters, take fk = uf-2.57σf. And tensile material sub-coefficient of 1.8, and the shear coefficient of 3.2 and GB50068 and GB50017 inconsistent, GB50068 Article 1.0.3 provides: "to develop the structure Load specifications and steel structure design specifications, such as ----- should comply with the provisions of this specification. My personal opinion or by GB50068 implementation.
2. Anchor bearing resistance to pull-carrying capacity test,
From the test situation to see the back bolt and stone anchor all the stone punching damage, damage to the state of stone taper damage, the impact of damage factors are back bolt diameter, back bolt bolt depth, the strength of the stone itself, in which the most direct impact of anchor depth, And when the anchor depth is equal to less than 12mm, the carrying capacity of the disruption of the larger, the regression statistics, anti-tensile load-bearing capacity of the anchor by the depth of 1.5 index growth, the substrate strength against the load carrying capacity of 0.5 growth index, 6mm back Bearing capacity of 4.5KN ~ 8KN, φ8mm back bolt anti-drawing bearing capacity of 5KN ~ 10KN, φ12mm back bolt anti-pull carrying capacity of 6KN ~ 12KN.
Above the standard value of the carrying capacity, the test results will pull out the mathematical statistics, the average minus 1.645 times the standard deviation, the anchor depth ≤ 12mm larger discrepancies, the standard deviation is also large, according to fK = μf-1.645σf The discretization has been taken into account and no further reduction of the coefficient is necessary. Its design value fTV = fK / 2.143 / 2. The bending strength of the stone can be calculated by the engineering stress method only when the stone is subjected to compression (bending) test:
Τ = P / [π * h / cosα * (D + h * tanα)] ≦ fT
3, anchor long-term static load test
(8500H). The tests are divided into long-term static load test and pull-out test. The results show that the tensile strength of the back anchor is different from that of the anchor. , Shear test refers to the bolt in the load under the shear load by 8500H, the tensile test specimen to do the ultimate pullout test and the long-term load test specimens for comparison, the test results show good shear resistance, No damage or displacement was observed in the long-term pull-out test, except that the assembly gap displacement (≤0.3mm) was not observed during the initial loading period.
Indicating that the connection between the back bolt and the stone is very reliable even under long-term external load.
4, the anchor load of the anchor fatigue test, that is repeated fatigue test load.
In the positive pressure 3 million + negative pressure 3 million times the reciprocating dynamic load fatigue resistance test, with nylon plastic sleeve back bolt in the bolt and the hole between the three-way isolation effect of shock isolation, under impact The single-section back bolt can not be damaged or moved obviously due to the back bolt's own activities and the pressure and pull action of the reciprocating motive force in the multi-million times strong reciprocating dynamic load fatigue test. , The worst in the 126 negative pressure damage, it can be seen with the best back bolt nylon sleeve, and the use of double-cross-section of the back bolt and stone to be the first fastening.
5, seismic testing
China Academy of Building Research, China Academy of Water Sciences for a number of stone curtain wall seismic performance shaking table test. Test results show that the earthquake acceleration 0.6g or less (equivalent to the intensity of 9.7 degrees) when everything is normal, South China Institute of Urban Earthquake Center test found in 0.6g when the back bolt has loosening signs, 0.8g (equivalent to 10 degrees) curtain wall Hook is out of the beam may be analyzed by the main bolt hole is not required by the processing requirements, the use of single-sided non-nylon mattress back bolt, curtain wall components hook and beam lap less than 6mm. Other tests used a double-face nylon bolt with a back bolt, curtain wall unit component hook and beam lap height greater than 10mm, even at 0.9g (equivalent to 10.2 degrees of intensity), the inter-layer displacement of 1/54, the back The connection between granite curtain walls remains intact, and the anti-pull ability of stone bolts and stone anchors in the specimens subjected to seismic tests is almost the same as that of the specimens without earthquake resistance test.
It can be seen from the above test, back bolt type granite curtain wall connection in the specification of the use of the range (6-8 degrees area), can be used without nylon plastic sleeve single-sided back bolt, when used for 9 degrees And 9 degrees above the intensity of the area, should be used with nylon plastic sleeve sets of double-section back bolt. The height of the lap joint between the curtain wall component and the beam should not be less than 10mm.
1, structural design
First of all, to establish a concept: the back bolt is a fastener, which stone and stone curtain wall components in the link together, it is
In the freely removable fastener, the connecting member may be designed as desired in accordance with the construction requirements of the glass (metal) curtain wall in each curtain wall which is combined with the stone curtain wall. For example, and extrapolation hidden curtain wall (small unit curtain wall) can be used in combination with the plug-in matching connector, with the back bolt to the stone fixed on the extrapolation of the box.
Stone and connecting pieces of connection, depending on stone size and construction requirements can be used a back bolt, two back bolt, four back bolt and so on.
When using a back bolt, the hole should generally be located in the center of the board, the hole to the edge of the board is not greater than 300mm, plates and connectors should also use 4 nylon bolts to withstand the inside of the board to keep the board stable.
When using two back bolts, the hole in the top edge of the board to the distance of not more than 400mm, to the side is not greater than 300mm, both sides of the back bolt with nylon bolts to withstand the inside of the plate to keep the plate stable.
When using four bolts, the hole in the board edge distance of not more than 250mm.
Back bolt and hole construction requirements are as follows:
Table 1
Type Drilling diameter Anchor depth Connection bolt Maximum anchorage thickness Bottom hole diameter Minimum plate thickness
FZP 11 × 12M6 / 3A4 11 12 M6 3 13.5 20
FZP11 x 12M6 / 9A4 11 12 M6 9 13.5 20
FZP 11 × 15M6 / 6A4 11 15 M6 6 13.5 28
FZP 13 × 15M8 / 4A4 13 15 M8 4 15.5 28
FZP 13 × 15M8 / 25A4 13 15 M8 25 15.5 35
FZP13 × 20M8 / 10A4 13 20 M8 10 15.5 35
FZP13 × 21M8w / 5A4 13 21 M8 5 15.5 35
FZP13 × 21M8w / 20A4 13 21 M8 20 15.5 35
FZP 11 × 19M6 / 6kt / 3AL 11 10 ~ 14 M6 3 13.5 20
FZP 11 × 21M6 / 6kt / 4AL 11 12 ~ 16 M6 4 13.5 20
FZP13 × 24M6 / 6kt / 3AL 13 15~19 M8 3 15.5 30
FZP 13 × 26M8 / 6kt / 5AL 13 17~21 M8 5 15.5 34
FZP 11 × 21M6 / ES / 4AL 11 12 to 16 M6 4 13.5 20
FZP 13 × 24M8 / ES / 4AL 13 15~19 M8 4 15.5 30
Back bolt and stone anchor parts of the construction quality is an important part of the limit (tolerance) with the determination and testing requirements hole deviation
± 0.5mm, hole deviation ± 0.5mm, hole distance and hole deviation of not more than ± 1.0mm, aperture (φ6 ~ 8mm) +0.4 mm, -0.2mm,
Hole depth + 0.4mm, -0.1mm, the bottom hole diameter of ± 0.3mm.
2. Design calculations
A. One plate with a back bolt
P = qA
(0.64 L / t) +1.062] ≤ fT or σ = (P / t2) * [0.5563Ln (0.64L / t)
U = C x (P x L2 / E x t3)
Table 2
LX / LY (LY / LX) C
1.0 0.1265
1.1 0.1381
1.2 0.1478
1.4 0.1621
1.6 0.1714
1.8 0.1769
2.0 0.1803
3.0 0.184
∞ 0.1849
Τ = P / [π * h / cosα * (D + h * tanα)]
Where: L - LX, Ly the smaller (mm); t - thickness (mm);
D - anchor hole diameter (mm); h - anchor hole depth (mm).
B. One plate is anchored with two back bolts, which can be simplified as simply supported plates with cantilever at both ends
MA = MB = -qa2 / 2
R = qL / 2
Mφ = qL2 / 8 × 1 - 4 × a / L 2 -
(A / L) 2 + 3 (a / L) 3] uC = uD = qaL2 / 24EI [
Uφ = qL4 / 384EI [5-24 (a / L) 2]
Τ = R / [π * h / cosα * (D + h * tanα)]
C. One plate is anchored with four back bolts and is calculated as a quadrangular support plate
Σ = 6mqL2 / t2
Where: L - LX, Ly in the larger;
M - bending moment coefficient.
Τ = (qa / 4 * 1.25) / [π * h / cosα * (D + h * tanα)]
Table 3 Bending moment coefficient table
LX / LY m
0.50 0.1304
0.55 0.1320
0.60 0.1339
0.65 0.1361
0.70 0.1384
0.75
0.80 0.1435
0.85 0.1464
0.90 0.1494
0.95 0.1526
1.00 0.1559
Table 4 Natural granite slab strength classification table N / mm2 t
Grade strength Standard value Design value of flexural strength fr Shear strength design value ftv Elastic modulus
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