1) Description of Multi-storey building system:
The primary structural elements of a multi-storey steel building, namely
the columns and floor beams, should be laid out with a view to minimising both the cost of the steelwork and the time required for its erection. For any given structure a layout can be determined that optimises the combined beam and column content of the structure, but in most cases functional and architectural considerations have to be taken into account, which mitigates against the design of optimal bay sizes. Consultation between the architect and the engineer in the early stages of planning could help to prevent an uneconomical layout having to be adopted.
The third structural element, after the columns and beams, is
the stabilising system necessary to provide lateral support to the building, i.e.to supply stability under gravity loading and to resist the overturning effects of wind. Obviously, the taller the building the more important the bracing system becomes and in very tall structures the provision of adequate lateral support does in fact become the dominant consideration.
Lateral stability may be provided within the steel structure itself by means of bracing, or moment-resisting beam-column connections or steel shearwalls, or it may be imparted by other building elements, e.g. reinforced concrete service towers, or concrete or brick in-fill panels in the walls. In all cases the stabilising elements may be located within the plan dimensions of the building or in the perimeter walls, or they may even be external to the building.
If a building is to incorporate the stabilising system within the steel structure, the framework can be of the
two-way braced, one-way braced and one-way-rigid, or two-way rigid type.Triangulated bracing is usually cheaper than a stiff moment-resisting frame and should be used wherever access problems do not arise, i.e. where door, window or service openings are not required.
In addition to vertical bracing systems it is necessary to provide stiffness within the plane of each floor, both to maintain the squareness of the floor in plan and to transmit the wind loading on the exterior of the building to the vertical bracing.
Stabilising systems - examples
Figs 7.1 to 7.5 give examples of various bracing systems that can be employed to provide stability to multi-storey buildings. The examples are of general application and illustrate the basic principles involved in such systems. The vertical steel bracing is shown as the X-type for simplicity, but could equally well be
chevron bracing, knee bracing or someother type (the features of the various bracing types are discussed more fully in Chapter 11). The floors are shown as steel-braced, but in practice the bracing function could be furnished by the concrete floor slab, in which case only nominal squaring-up
steel bracing would be required. The systems are applicable to buildings of almost any number of storeys.
Two-way steel bracing
The two-way steel braced system shown in Fig 7.1 is one of the most efficient in terms of stiffness, speed of erection and economy. All beam-to-column connections are of the simple (i.e. hinged) type, so labour input in both columns and beams is minimised and erection can proceed quickly. Being fully steel-framed, the structure is self-supporting and can be completely erected without having to be integrated with other trades. The only drawback is the presence of the braced panels in the exterior walls, which might interfere with the window pattern, but in the light of the current trend towards exposed steelwork
the windows could be set back and the bracing system be expressed boldly as an architectural feature. In very long buildings it would be necessary to provide one or more interior sets of bracing, as shown dotted.
One-way steel bracing
The stiff frame shown in the alternative end elevation of Fig 7.1 is another method of providing transverse stiffness to the structure. All of the transverse frames not only the end ones, would be stiff, but the building would still rely for longitudinal stiffness on the two sets of one-way bracing in the sides. This would be a more costly arrangement than the two-way braced solution, but would remove the drawbacks of the triangulated bracing.
It is more suited to long buildings and has the further advantage that the main (i.e.transverse) floor beams could be shallower, because of their continuity, with consequent reduction in storey height.It must be emphasised, however, that on purely economic grounds triangulated bracing is very much more cost-effective than a moment frame, both in shop fabrication and in erection.
Central service core
Where a building is fairly compact in plan and does not have a great length-to-width ratio,a central service core is a very efficient means of providing stability, as shown in Fig 7.2. e Elevation
Floor framing
In steel-framed buildings the floor framing system almost invariably consists of a series of
main and secondary beams at right angles to each other in plan, with the secondary beams framing into or passing over the tops of the main beams. The floor slab or deck is then carried on top of the secondary beams.
Except where stiff-frame action is required, as discussed under Stabilising Systems above, the main beams are usually simply-supported spans between the columns. If the secondary beams have their top flanges flush with the tops of the main beams they would be framed into the webs of the main beams and would thus also be simply-supported; this would produce a floor grid of minimum depth and would result in a reduction in storey height. However, underfloor services running at right angles to the main beams would then have to pass through holes formed in the webs of these beams, or else be routed
below the main beams, which would increase the floor depth.
If the secondary beams pass over the tops of the main beams, however, they would no longer be simply-supported but be continuous, significantly reducing the mass and especially deflection. The routing of services in both rectangular directions in plan would be facilitated by reason of the space available above the main beams.
The two beam framing systems referred to above represent conventional practice as used on the great majority of small to medium-sized buildings. The beams are ofstraightforward construction and employ standard end connections and are thus easy and cheap to fabricate. A number of non-standard options are available and are worth considering for larger buildings where a high level of repetition of components would justify their use. These are discussed below.
Twin beams
Main beams span between columns and can therefore not normally be made continuous.Continuity can, however, be achieved by replacing the beam by a pair of closely-spaced twin beams passing on each side of the column, as shown in Fig 7.6.
Because of their continuity the main beams can now be designed plastically, for acombined moment on the two beams of 70 per cent or less of that for the simply-supported single beam, and at a combined mass m about equal to that of the single
beam. As regards deflection, the twin-beam system would tend to be more stiff than a single simply-supported beam of the same load capacity because of the continuity. The labour input for the twin beams would be more, but this alternative is useful when it is desired to reduce the depth of the floor (and thus the storey height), or on long spans where the twin rolled I-sections replace a more expensive single welded plate girder.
Elevation and floor plan of a typcial multi-story steel building:
As we have discussed the structure side of a multi-story steel building,now it's time that we discuss about the wall and roof cladding and interior and exterior wall finish and decoration options:
For the panel,we have our latest foam panel,fiber cement panel.Gypsum board will be a good option for the partition wall.For the ceiling,gypsum,PVC or integrated ceiling are both OK.All these panel options are open to further decorative finish option.
Our last concern would be the EIFS(EXTERNAL INSULATION FINISHING SYSTEM).Our suggestion would be the integrated insulated decoration panel because it has perfect thermal insulation performance with various pattern and color choices.
You are so welcome to send us inquiries!
| Offer request |
| Type of Building |
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| Please state type of building, ie: workshop, warehouse, hall, hangar, farm, roof structure or other construction |
| Dimension |
a(width) |
b(length) |
h1(wall height) |
h2(total height) |
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| Construction Site |
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| Roofing and Walls |
(1)sandwich panel
(2)profile steel sheets
(3)steel sheet+glasswool blanket
(4) no walls-only roof with structures |
| Contact Name |
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| Company Name |
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| Phone Number |
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| Email |
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| Additional info |
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| Send us sketches, drawings or the project, if you have |
KXD's H Section Manufacturing Equipment and Process
Steel plate cutting→H section assembly→Automatic welding-H section strengthening→Assembly→Manual welding→Shot blasting-Painting→
Storage
I.Steel plate cutting
The H section steel plate should be checked again by the factory and shall be applied under the condition of up to design and specified requirements after checking. Steel plate cutting should be aimed at quality guarantee and material saving. For each process like plate cutting,H type assembly, components assembly and pre-assembly should be carried out by profession setting-out worker precisely on processing surface and assembly sample plates.To guarantee the accuracy of the components'geometrical dimension,tolerance of form and position, angle and contact surface,inspection is necessary by inspector after setting out.In order to ensure the cutting quality,the surface of the ultra-thick plate is subjected to the surface carburizing hardness test before cutting.The CNC cutting equipment is preferred for cutting.The high purity 98.0% acrylic gas and 99.99% liquid oxygen gas are used to guarantee the smoothness and flatness of the cutting surface without notches and slags.The groove is cut by a special imported cutting machine.
Equipment name: Portable CNC Fire-cutting machine
Model No.: CNCDG-1530
Application feature: steel plate cutting(5-100mm plate cutting thickness), beveling of the edge.Advantageous in small equipment and easy-to-move. Mainly for cutting regular and irregular small components and beveling of the plate.
Equipment name:Straight flame cutting machine
Model No.:DZCG-4000A
Application feature:steel plate cutting(5-100mm plate cutting thickness),Y flange plate, web plate cutting, effective cutting width: 3200mm
Equipment name:CNC cutting machine
Model No.:CNC-4000C
Application feature:steel plate cutting(5-100mm plate cutting thickness),Y flange plate,web plate and irregular component cutting,effective cutting width: 3200mm
Equipment name: Radial drilling machine
Model No.:Z3050*16/1
Application feature:Maximum drilling diameter φ50mm,Mainly for processing of component bolt-connection holes
Equipment name:Puncher machine
Model No.:JH21-400
Application feature:Maximum stamping pressure-400 ton,Mainly for plate punching, blanking, bending and shallow stretching
Equipment name:Shearing machine
Model No.:Q11Y-25*2500
Application feature:cutting width 2500mm and cutting thickness 3-25mm
II.H section steel assembly
The assembly process is set up on the imported H section production line.4 hydraulic positioning system press firmly against between the upper/lower flange and web plates in position. The adjust the parallelism of the flange plates and perpendicularity between flange and web plates and get them fixed after. The fixing welding should adopt C02 gas shielded welding.
Equipment name:H section steel assembly machine
Model No.:Z20B
Application feature:mainly for H type assembly u,flange width 150-800mm,web height 160-2000 mm
III.Automatic welding
The H section steel members will be hoisted into the gantry-type submerged arc automatic welding machine for welding.The welding process should be carried out in accordance with specified welding sequence and regulation parameters.Preheating, which uses the electrical heaters, is necessary for the ultra-thick plates of components.The set temperature shall be determined based on the specified one.Please see factory welding process documents for detail.
Equipment name: Gantry-type submerged arc automatic welding machine
Model No.:LHA5ZB
Application feature:Mainly for assembly welding of H section steel whose maximum cross section up to 800mm×2000mm
IV.H section steel strengthening machine
H section steel strengthening process: Correction of flange flatness by using H section steel flange plate strengthening machine.Flame-correct the perpendicularity between the H section flange and web plate under special circumstances and then correct the side bending of the H section steel. The flame temperature should be controlled under the range of 600~800ºC.
Equipment name:H section steel strengthening machine
Model No.:YTJ60B
Application feature:Mainly for correcting the deformation of I beam or H section steel flange plate during welding process,flange width 200-1000mm, flange thickness≤60mm, web height≥350mm
Equipment name:H section flange strengthening machine
Model No.: HYJ-800
Application feature:Mainly for correcting the deformation of I beam or H section steel flange plate during welding process,flange width 160-800mm,flange thickness≤40mm,web height≥160mm
V.Simulated assembly of component
1.Get familiar with component shop drawing and technical requirements.
2.The model components need to re-check by related department after making and finalizing of the model components and then to assemble.
3.Accurate mark-up
4.Inspect the component after first assembly.For multi-group components, pre-assembly for the first group and then batch assembly after qualified test.
VI.Manual welding
VII.Shot blasting
Equipment name:10-ramming heads shot blasting machine
Model No.:QH1525
Application feature:Mainly for shot blasting of section steels including H section steel, welded members and steel plate,10 ramming head; Machine entry size:1500Í2500 and member at 1200Í2000 size could pass the machine at once; up to Sa2.5 Grade.
VIII.Painting
The surface of the members should be in even,flat, glossy and full painting without manifest of cracking, peeling and pin holing.The color and coating thickness should also meet design requirements.If there is no certain requirements,the following standards should be followed:thickness is 150μm indoor while 125μm outdoor.The allowable deviation is -25μm.The allowable deviation of dry paint film thickness for each-time painting
Two coats of primer:thickness being40±5μm; Two coats of finish paint:thickness being 60±5μm.
Equipment name:Airless sprayer
Model No.:CPQ9CA
Application feature: Derived capacity:56 L/min,Air consumption:50~1200 L/min.Mainly for surface paint of structural members, Pressure ration: 32:1
Process, fabrication and quality control standard on welding groove/beveling of steel structure
1. Purpose
To ensure the welding quality, meeting up the technical requirements of welded members and improve the standardization of our fabrication, we specially formulate this regulation.
2. Application scope
This manual apply for the design, fabricate and inspection of groove joint in terms of manual arc welding, CO2 arch welding, mixed gas arch welding, submerged arc welding and electroslag welding.
3. Design of welding groove
3.1 Key points on design welding groove:
In order to obtain quality groove, it is necessary to choose appropriate form of groove. The option of groove mainly depends on the thickness of base metal, welding method and craftsmanship requirements.The followings are the factors we need to consider:
- minimize the amount of filler metal
- easy for beveling
- in convenience for welding operation and slag removal
- After welding stress and deformation should be as small as possible
3.2 Groove direction:
We will consider the following factors for the groove direction:
A)in favor of welding process and removing slag and leave enough space for welding process on the fusion face
B)minimize the times of flip-flop during welding
C)way of fit-up in actual welding
3.3. Regulation on groove direction of members:
3.3.1 Butt welding on H section rafter/column (when CJP-complete joint penetration and single side fusion is required)
1) When there is no welding backing, the groove orientation on flange plates should be same and falls on the direction in favor of welding on web plats(same rules apply for the PJP situation). Please refer to illustration 1
2)When there is welding backing, we require the groove direction being outward for the flange plates(opposite direction for web plates) and still falls on the direction in favor of welding on web plates. Please refer to illustration 2
3)Butt-welding on construction site:we require all the grooves should be bevelled on the upper rafter/column when it comes to bolt connection for web plates(see illustration 3). For the scenario of welding on web plates, please refer to the illustration 4.
3.3.2 Box column(groove on itself).See illustration 5
4. Welding groove form
4.1. Mark on form and size of welding joint groove:
Example: Shielded metal arch welding, complete joint penetration, butt welding, I shape groove, welding backing and single side weld would be marked MC-BI-BS1
4.2. For the mark of welding method and penetration type, please see the following chart 1.
Chart 1 Mark on welding method and penetration type
| Mark |
Welding method |
Penetration type |
| MC |
Shielded metal arch welding |
CJP-complete joint penetration |
| MP |
PJP-partial joint penetration |
| GC |
Shielded arch welding
Self-shielded arc welding |
CJP-complete joint penetration |
| GP |
PJP-partial joint penetration |
| SC |
Submerged arc welding |
CJP-complete joint penetration |
| SP |
PJP-partial joint penetration |
| SL |
Electroslag welding |
|
4.3. For the mark of single, double side welding and backing material type, please see the following chart 2
Chart 2 Single/double side welding and backing material type mark
| Backing material type |
Single/double side welding |
| Mark |
Material |
Mark |
Single/double side welding |
| BS |
Metal backing |
1 |
Single side welding |
| BF |
Other backing |
2 |
Double side welding |
4.4. Mark on each part size of groove, see chart 3.
Chart 3 Size mark on groove
| Mark |
Size of each part on groove |
| t |
Thickness of welding plate(mm) |
| b |
Groove root gap or gap between two members(mm) |
| h |
Groove depth(mm) |
| p |
Groove roof face(mm) |
| α |
Groove angle(º) |
Applicable Codes
LATEST INTERNATIONAL CODES COMPLIANCE
A. (GB50009-2012): Load code for the design of building structures
Loads on all buildings are applied in accordance with:
2012 edition of the Load code for the design of building structures
B. (MOHURD): Ministry of Housing and Urban-Rural Development of the People's Republic of China
Manufacturing and Erection tolerances are applied as per:
GB50205-2001 edition Code for acceptance of construction quality of steel structures
C.(MOHURD): Ministry of Housing and Urban-Rural Development of the People's Republic of China Hot rolled sections and built up sections are designed in accordance with:
GB50017-2017 Code for design of steel structure
D. CISA - China Iron & Steel Association - Latest Edition
Cold formed members are designed in accordance with:
GB50018-2002 Technical code of cold-formed thin wall steel structures
E. (MOHURD): Ministry of Housing and Urban-Rural Development of the People's Republic of China
Welding is applied in accordance with:
JGJ81-2002 Technical specification for Welding of steel structure of building
F. Surface treatments are applied in accordance with:
GB/T 8923.1 Preparation of steel substrates before application of paints and related products-Visual assessment of surface cleanliness-Part 1: Rust grades and preparation grade of uncoated steel substrates and of steel substrates after overall removal of previous coatings
STRICT DEFLECTION CRITERIA
| Deflection |
Type of structural members |
Deflection Limitation |
| Vertical Deflection |
Portal frame rafter |
Only support corrugated steel sheets roof and cold-formed section purlins |
L/180 |
| If there is ceiling system |
L/240 |
| If there is top running crane |
L/400 |
| Mezzanine floor |
Main beam |
L/400 |
| Secondary beam |
L/250 |
| Purlins |
Only support corrugated steel sheets roof |
L/150 |
| If there is ceiling system |
L/240 |
| Corrugated roof steel sheet |
L/150 |
| Lateral Deflection |
Wall panel |
L/100 |
| Wind columns or wind truss structures |
L/250 |
| Wall beam |
Only support corrugated steel sheet wall |
L/100 |
| Support masonry wall |
L/180 and ≤50mm |
Material Specifications
The material standards for which the building components have been designed as per specifications.
STANDARD MATERIAL SPECIFICATIONS
| Material Specifications |
| No |
Components |
Specifications |
Minimum yield strength |
Applicable Design Code |
| 1 |
Built -up
(Plates) |
GB/T1591-2008 |
Fy = 34.5 kN/cm2 |
CISA - China Iron & Steel Association - Latest Edition |
| 2 |
Hot Rolled |
Angles |
GB/T3274-2007 |
Fy = 23.5 kN/cm2 |
CISA - China Iron & Steel Association - Latest Edition |
Beams |
GB/T11263-2010 |
Fy = 23.5 kN/cm2 |
CISA - China Iron & Steel Association - Latest Edition |
| 3 |
Cold Form
|
Galvanized |
GB/T 2518-2008 |
Fy = 45.0 kN/cm2 |
CISA - China Iron & Steel Association - Latest Edition |
| 4 |
Roof panel/Wall panel
(Zinc) |
GB/T12754-2006 |
Fy = 34.5 kN/cm2 |
CISA - China Iron & Steel Association - Latest Edition |
| 5 |
Roof panel/Wall panel
(Alu) |
GB/T12754-2006 |
Fy = 34.5 kN/cm2 |
CISA - China Iron & Steel Association - Latest Edition |
| 6 |
X-Bracing |
Galvanized cable bracing |
GB/T 700-2006 |
Fu = 157 kN/cm2 |
CISA - China Iron & Steel Association - Latest Edition |
| 7 |
Anchor bolts
|
GB/T 700-2006 |
Fu = 40.0 kN/cm2 |
CISA - China Iron & Steel Association - Latest Edition |
| 8 |
High strength Bolts |
GB/T 1228-2006 |
Ft = 30.3 kN/cm2
Fu = 72 to 83 kN/cm2 |
CISA - China Iron & Steel Association - Latest Edition |
| 9 |
Machine Bolts
|
GB/T 1228-2006 |
Ft = 13.8 kN/cm2
Fu = 41.0 kN/cm2 |
CISA - China Iron & Steel Association - Latest Edition |
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