2018-07-20 15:39:34

Space frame designning explaination and construction requirements

Project Overview
Project name
Project site
Project scale (space frame projected area) see pic
Project structure:    
   Orthogonal spatial square pyramid grid with bolt-sphere joints
   Space frame support mode: Bottom chord column support
   Space frame plan size and rise: see it in the plan and elevation of the space frame roof system
Safety level: second level
Usage: 50 years

Design Overview
1. This project adopts SFCAD2006 FOR WINDOWS software to auxiliary design.
2. Design principles of space frame:  external load of space frame made the load concentrate in the joints according to the static equivalent principle. Pls ignore the ffect of the joint stiffness when you calculate and suppose joints are hinged joint andm ember bars only bear axial force. We adopt space truss displacement method when we design.
3. Control stress of member bar: f≤185N/mm2
4. Control limit of member bar’s slenderness ratio: compression bar ג≤180 tie bar ג≤180
5. Deflection control of space frame: w≤L/250

Basis of design, construction and quality evaluation
Architectural structure load standards (GB50009-2012)
Earthquake Resistant Design Code     (GB50011-2010)
Space frame structure technology procedures(JGJ7-2010)
Steel structure design standards(GB50017-2003)
Structural reliability design standard(GB50068-2001)
Cold-formed thin-walled steel structure technical specifications(GB50018-2002)
Roof Construction Technology Code(GB50345-2004)
Steel structure construction quality acceptance code(GB50205-2001)
Space frame nodes with high strength bolts(GB/T16939-1997)
Steel space frame bolt-sphere joints(JG/T10-2009)
This project’s technical files and relevant documents

System loads( not contain the space frame’s self-weight)
Dead load of top chord: 0.20KN/m2
Dead load of bottom chord: 0.20KN/m2
Live load of roof: 0.50KN/m2
Wind load:0.30KN/M2
Snow load:1.30KN/M2
Seismic fortification: 9℃
7. Temperature:±40℃

Space frame materials
1.Steel tube: it adopts Q235B steel. Apply to the “Space frame nodes with high strength bolts” regulation.
2.Bolt ball: 45# steel should be produced and tested according to the “Steel space frame  bolt-sphere joints” standard.
3.High strength bolt: 40Cr
4. Blanking plate and conehead: Q235B steel
5. Bearing and bracket: Q235B steel
6.Sockets: Adopt Q235B steel when the socket’s inner diameter is 13.5~34, when the  socket’s inner diameter is 37 or bigger, it will adopt Q345B steel or 45# steel.
7.Welding rod: It will adopt E43 series when Q235B steel welds with Q235B steel. It will adopt E43 series when Q235B steel welds with 45# steel. It will adopt E506 series when Q345B steel welds with 45# steel.

Processing technical specifications
1.Steel yield strength and tensile strength measured values of the ratio of the measured values should not be greater than 0.85
Steel should be obvious to yield level,while elongation should not less than 20%,should have good weldability and qualified steel impact toughness,Material all need warranty and the physical and chemical test report,The ball must hit number and all products shall comply with the quality of the steel rack industry standards.
2.Space rods, bolted ball, bearing, bracket, sleeve, and anti-corrosive paint twice after sandblasting derusting
3.Space frame components (including bolted ball, bars, high strength bolts, bearings, etc.) should be made in the factory with Inspection records,Ball and bolt processing, comply with the machinery industry standard on its own processing or purchased and chosed  by the manufacturer,But all should meet the requirements of space frame design and construction stage of stress, deformation, etc
4.Components welding should use equal strength, no slag weld nor bubbles, weld strength
  should be higher than the parent metal,Bearing ball must use E506 or E4303 electrode for welding, and only could be welded when heat reach o 150 degree.
5.Weld quality gradeLButt welding for level 1, Angle seam welding for level 3

Installation technical specifications
1.Bearing surface of embedded steel plate must be level, position accurately, the orientation deviation is not more than 15 mm,Adjacent bearing elevation difference is not more than 5 mm, the surface in the vertical elevation difference is not more than 10 mm,
2.To eliminate the error of the civil engineering in the embedded steel plate,space frame construction should use transition plate.
3.After space frame installation, vertical and horizontal to the side length deviation value shall be 1/2000 of the length, and not more than 30 mm,Center offset value shall be 1/3000 of the space frame span, and should not more than 30 mm.The vertical deviation value shall be 1/800 of the adjacent bearing spacing, and should not be greater than 15 mm, elevation difference between the highest and lowest support should be not more than 30 mm
4.After the construction of network frame deflection is not greater than the design value 15% (W)

Space frame structure Corrosion protection and fire prevention
1.derusting: before making steel structure ,surface should be sandblasting derusting  treatment (shotting). Derusting quality level should reach national standard GB8923 sa2.5 level standard
2.Coating: space truss structures, steel purlin two underlying spraying anti-corrosion primer after derusting, paint two way,after installation components need touch-up
3.Steel structure fire retardant coating surface coating, fire rating is secondary grade, material decided by party A.

Engineering measurement units
Not indicated length unit is mm
Not  indicated internal force unit is KN

Ruling without details should comply with current specification of the industry, discipline standards and other related requirements
Drawings without audit stamp, should not construction