9.1.1 This section is mainly applicable to the assembled type single-storey factory buildings with R.C.Columns and the structural layout shall be in accordance with the following requirements:
1 Multi-span factory building should be equal in height and length and the high-low span factory building should not be adopted with structural layout featured by one-end opening.
2 Auxiliary buildings and structure of a factory building should not be arranged at the corners of the buildings or close to the seismic joints.
3 Where the factory building body is complex or there are auxiliary houses and structures, seismic joints should be adopted; At the longitudinal and traverse span intersection part of factory building, the seismic joint width of large column-grid factory building or factory building without inter-column support may be 100mm~150 mm and for the other conditions, it may be 50 mm~90 mm.
4 The transition span between two main buildings shall at least be provided with seismic joint at one end in order to be detached from the main building.
5 The iron ladder of crane in factory building shall not be laid close to the seismic joint; the iron ladder of crane at each span of multi-span factory building should not be erected near the same transverse axial line.
6 The operating platform and rigid workshop in factory building should be detached from the major factory building structure.
7 Different structure forms shall not be adopted in the same structural unit of factory building; the factory building end shall be installed with roof truss and with the gable wall shall not be used to bear load; transverse wall and bent frame shall not be used together to bear load in factory building unit.
8 The column space in factory building should be equal; the lateral rigidity of each colonnade should be uniform; where the column is removed, seismic measures shall be taken.
Note: The seismic design for concrete frame-bent structure factory building shall be in accordance with the requirements of Section H.1 in Appendix H of this code. 9.1.2 The installation of factory building skylight truss shall be in accordance with the following requirements:
1 Skylight should be adopted with the wind-sheltered skylight with smaller part extending the roof and sunken skylight should be adopted if possible or where it is for Intensity 9 .
2 The skylight protruding roof should be adopted with steel skylight truss; where it is for Intensity 6~8, reinforced concrete skylight truss with rectangular section member bar may be adopted.
3 The skylight truss should not be installed from the first bay of factory building structural unit; where it is for Intensity 8 and 9, the skylight truss should be installed from the
third bay of factory building unit end.
4 The skylight roof, front sheet and side sheet should be adopted with light sheets; the front sheet shall not replace the end skylight truss.
9.1.3 The installation of factory building roof truss shall be in accordance with the following requirements:
1 Factory building should be adopted with steel roof truss or the roof truss with pre-stressed concrete and reinforced concrete of lower gravity center.
2 Where the span is not greater than 15m, roof beam with reinforced concrete may be adopted.
3 Where the span is greater than 24m or it is Intensity 8 with site class III and IV and Intensity 9, the steel roof truss shall be adopted in priority.
4 Where the column space is 12m, pre-stressed concrete bracket (beam) may be adopted; where steel roof truss is adopted, steel bracket (beam) may also be adopted.
5 The roof protruding the roof skylight truss should not be open web roof truss of pre-stressed concrete or reinforced concrete.
6 Where it is Intensity 8 (0.30g) and Intensity 9, factory building with span greater than 24m should not be adopted with large-scale roof slab.
9.1.4 Installation of factory building column shall be in accordance with the following requirements:
1 Where it is Intensity 8 and Intensity 9, rectangular or I-shaped section column or double leg column with diagonal web should be adopted instead of I-shape column of thin wall, I-shape column with open pore on web plate, I-shape column of prefabricated web plate or pipe column.
2 The column within the range of above 500mm form column root to indoor ground level and the column on the stepped column should be adopted rectangular section.
9.1.5 The arrangement of the enclosure wall and masonry parapet wall of the factory building, material selection as well as seismic structural measures shall be in accordance with relevant requirements in Section 13.3 of this code.
(II) Essentials in Calculation
9.1.6 Traverse and longitudinal seismic check may be omitted, where single-storey factory building adopts seismic structural measures according to the requirements of this code and any of the following conditions is met:
1 Single-span and equal-height multi-span factory building (expect zigzag-type factory building) with gable walls at both sides of the construction unit, for Intensity 7 at Class I and II site, column height no larger than 10m.
2 Open-air crane trestle for Intensity 7, Intensity 8 (0.20g) at Class I and II site. 9.1.7 The traverse seismic calculation of factory building shall be carried out with the following methods:
1 For the factory building without or with concrete purline roof, the traverse elastic deformation of roof, in general situation, shall be taken into account and shall be analyzed according to the multi-mass three-dimensional structure; where the conditions specified in Appendix J of this code are met, it may be calculated according to the plane bent frame and
the seismic shear force and bending moment shall be adjusted according to those specified in Appendix J.
2 For the light roof factory building, where the column spaces are equal, it may be calculated according to the plane bent frame.
Note: The light roof in this section refers to the purline roof of profile steel sheet, corrugated iron and so on.
9.1.8 The longitudinal seismic calculation of factory building shall be carried out with the following methods:
1 The light roof factory building without or with concrete purline roof and with integrated support system may be adopted with the following methods:
1) Typically, the longitudinal elastic deformation of roof and the effective rigidity of enclosure wall and partition wall should be taken into account; where it is unsymmetrical, torsion influence should also be taken into account and the three-dimensional structure analysis shall be carried out according to the multi-mass.
2) As for single-span or equal-height multi-span reinforced concrete column factory building with column top elevation and average span less than or equal to 15m and 30 m respectively, it should be calculated according to the modifying rigidity method as specified in Section K.1 of Appendix K in this code.
2 For the single span factory building with longitudinal walls symmetrically laid out and the light roof multi-span factory building, it may be calculated independently according to the colonnade piece by piece.
9.1.9 The traverse seismic calculation of skylight truss protruding roof may be adopted with the following methods:
1 The traverse seismic calculation of the triple hinged arch reinforced concrete with diagonal and the steel skylight truss may be adopted with base shear method; where the span is greater than 9 m or for Intensity 9, the earthquake action effect of concrete skylight truss shall be multiplied by enhancement coefficient and its value may be 1.5.
2 The traverse earthquake action in other situations may be adopted with mode-decomposition response spectrum method.
9.1.10 The longitudinal seismic calculation of skylight truss protruding roof may be carried out with the following methods:
1 The longitudinal seismic calculation of skylight truss may be adopted with three-dimensional structure analysis method and the elastic deformation of roof surface and the effective rigidity of longitudinal wall shall be taken into account.
2 The longitudinal earthquake action calculation of skylight truss for factory building of single span with column height not exceeding 15 m and of equal-height multi-span concrete without purline roof may be adopted with base shear method; however, the earthquake action effect of skylight truss shall be multiplied by enhancement coefficient of effect and the value may be taken according to the following requirements:
1) For single span, side span roofs or mid-span roof with longitudinal internal partition wall:
n
5
.
0
1+
=
η
(9.1.10-1)2) For other mid-span roofs:
n
5
.
0
=
η
(9.1.10-2) Where:η
——the effect enhancement coefficient;n
——the span number of factory building; where there are more than four spans, it shall be taken as four spans.9.1.11 For the large column grid factory building with column space in two principal axis not less than 12 m, without overhead crane or column support, the seismic check of column section shall simultaneously calculate the horizontal earthquake action of the two principal axis directions as well as the additional bending moment due to personal drift.
9.1.12 The section area of longitudinal tension steel reinforcement supporting low-span column corbel (column shoulder) in non-equal-height factory building shall be determined according to the following formula:
s
A
≥
+
y E y o Gf
N
f
h
N
2
.
1
85
.
0
α
REγ
(9.1.12) Where: sA
——the section area of longitudinal horizontal tension steel reinforcement;G
N
——the design pressure value caused by the representative value of gravity load on column corbel surface;α——the distance from the gravity action point to the near edge of the lower column
bracket; where it is less than 0.3ho, it shall be equal 0.3ho; 0
h
——the effective height of the maximum corbel vertical section;E
N
——the designed horizontal pull value of seismic array on column corbel surface;y
f ——the design value of steel reinforcement tensile strength;
RE
γ
——the anti-seismic adjustment coefficient of bearing force, which may adopt 1.0. 9.1.13 For the earthquake action effect of cross support diagonal between columns and the anti-seismic of support connection joints shall be checked according to those specified in Article K.2 of Appendix K in this code. The lower joints of lower column inter-column support shall be positioned above the top surface of foundation according to those specified in Section 9.1.23 of this code; the oblique section shear bearing capacity of longitudinal colonnade column root should be checked.9.1.14 Wind-resistant column and roof truss column of the factory building, as well as seismic calculation with regard to the influence of working platform shall be in accordance with the following requirements:
1 For the wind-resistant column of high and large gable wall, where it is for Intensity 8 and Intensity 9, section seismic capacity check outside the plane shall be carried out.
2 Where wind-resistant column is connected with bottom chord of roof truss, the connection joints shall be set at the Transverse support of the bottom chord and the section and connecting joints of bottom chord transverse support bar shall be carried out with seismic capacity check.
3 Where the operating platform and rigid internal partition wall are connected with the major structure of factory building, calculation diagrams corresponding with actual load on factory building shall be adopted and the additional earthquake action influence of operating platform and rigid internal partition wall on factory building shall be taken into account. As for the bent-frame column with constrained dislocation and with shear span ratio not greater than 2, the shear bearing capacity of oblique section shall be calculated in accordance with those specified in the current national standard "Code for Design of Concrete Structures" (GB 50010) and corresponding details of seismic design shall be carried out according to those specified in Article 9.1.25 of this code.
4 As for Intensity 8 at Class III and IV site, for the arch with work column, broken line-type roof truss or the roof truss with longer joint space of top chord and lager vectorheight, the top chord should be checked for the torsion resistance.
(III) Details of Seismic Design
9.1.15 The connection and support layout of components with purline roof shall be in accordance with the following requirements:
1 The purline shall be well welded with the concrete roof truss (roof beam) and adequate support length shall be provided.
2 The double-ridge purline shall be tied at 1/3 section of span.
3 The profile steel sheet shall be reliably connected with purline and corrugated irons and asbestos tiles shall be tied with purlines.
4 Support layout should be in accordance with those specified in Table 9.1.15.
Table 9.1.15 Layout of Support with Purline Roof Intensity Support name 6, 7 8 9 Transverse support of top chord
It shall set a support for the bay at unit
end
It shall set a support in the unit end bay and the column support bay with unit length
greater than 66m ; It shall additionally set a partial support at both ends within the range of skylight
opening. Transverse support of bottom chord Mid-span vertical support
Same with non-seismic design
It shall set a support in the unit end bay and the column support bay with unitIt shall additionally set a partial top chord Transverse support at both ends within the range of skylight opening. length
greater than 42m; Roof truss
support
support column support bay. Transverse
support of top chord
It shall set a support for the bay at unit
skylight end Skylight truss support Vertical support at both sides
It shall set a support in unit skylight end bay and every
other 36m
It shall set a support in unit skylight end bay and every
other 30m
It shall set a support in unit skylight end bay and every other 18 m
9.1.16 The connection and the support layout of components without purline roof shall be in accordance with the following requirements:
1 Large scale roof slab shall be well- welded with roof truss (roof beam) and the connected weld length between roof slab and roof truss (roof beam) near colonnade should not be less than 80mm.
2 For the end bay of factory building unit with skylight for Intensity 6 and 7 and each bay for Intensity 8 and 9, the top surfaces of adjacent large scale roof slabs at both sides of the vertical roof truss direction shall be well welded with each other.
3 The embedded parts of large scale roof slab terminal bottom surface where it is for Intensity 8 and 9 should be adopted with angle steels and shall be well welded with the main reinforcement.
4 Nonstandard roof slab should be adopted with assembled monolithic joint or it shall be well welded with roof truss (roof beam) after cutting off the four corners of slab.
5 For the anchor bar of embedded parts at the top surface of roof truss (roof beam) end, where it is for Intensity 8, it should be greater than or equal to 4 φ 10; where it is for Intensity 9, it should be greater than or equal to 4φ12.
6 Support layout should be in accordance with those specified in Table 9.1.16-1; where there is intermediate well type skylight, it shall be in accordance with those specified in Table 9.1.16-2; where roof beam is adopted by factory building roof with span not greater than 15 m for Intensity 8 and 9, a vertical support may be set at both ends of factory building unit; the roof support layout of lean-to roof beam should be carried out according to that with the roof truss end height greater than 900 mm.
Table 9.1.16-1 Layout of Support without Purline Roof Intensity Support name 6, 7 8 9 Transverse support of top chord
Where the span of roof truss is less than 18 m, it
shall be in accordance with the non-seismic design; where the span is
not less than 18 m, a support shall be set in the
unit end bay of factory building.
A support shall be set in unit end bay and column support bay and an additional partial support shall be set at both ends within the range of
skylight opening Roof
truss support
Full-length horizontal tie bar
Same with non-seismic
design A support shall be set not greater than 15m along the span of roof
A support shall be set not greater than 12 m along the span of roof
of top chord truss; however, it may be set only within the range of skylight opening
for assembled monolithic roof; where cast-in-place ring beam is provided for enclosure wall on the
top chord height of roof truss, it may not be additionally set at the
end.
truss. However, it may be set only within the range of skylight opening
for assembled monolithic roof; where cast-in-place ring beam is provided for enclosure wall on the top chord height of roof truss, it may
not be additionally set at the end.
Transverse support of bottom
chord Mid-span vertical
support
Same with non-seismic design
Same with transverse support of top chord Roof truss end height ≤ 900m m
It shall set a support in unit end bay
It shall set a support in unit skylight end bay and every other 48 m Vertical support at both ends Roof truss end height >900m m
It shall set a support in each unit end bay
It shall set a support in each unit end bay and each column support bay.
It shall set a support in each unit end bay, column support bay and every
other 30 m
Vertical support at both sides of
skylight
It shall set a support in each unit skylight end bay
of factory building and every other 30m
It shall set a support in each unit skylight end bay of factory building
and every other 24m
It shall set a support in each unit skylight end bay of factory building
and every other 18m Skylight
truss
support Transverse support of top
chord
Same with non-seismic design
Where the skylight spans ≥9m, it shall set a support in each unit
skylight end bay and column support bay.
It shall set a support in each unit end bay and each column support bay
Table 9.1.16-2 Layout Support with Intermediate Well Skylight and Without Purline Roof Support name Intensity 6 and 7 Intensity 8 Intensity 9 Transverse support of top
chord
Transverse support of bottom chord
It shall set a support in each unit end bay of
factory building
A support shall be set in each unit end bay of factory building and each column support bay
Full-length horizontal tie bar of top chord
Set at top chord joints of roof truss mid-span within the range of skylight Full-length horizontal tie bar of
the bottom chord
Set at the bottom chord joint of roof truss within the range of skylight and at both sides of skylight
full-length tie bar of bottom chord Roof truss end
height ≤900m m
Same with non-seismic design
There is transverse support bay of top chord and the space is not
greater than 48 m Vertical
support at both
ends Roof truss end