The design of lightweight structures realized via additive manufacturing has been drawing considerable amount of attentions in academia and industries for a wide range of applications. However, various challenges remain for AM lightweight structures
this example will guiding student to calculate timber structure.Deskripsi lengkap
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Structural engineeringFull description
Solar Mounting Structure Design for BTS Site by Nizam Energy Pvt. Ltd.
DESIGN CALCULATION FOR SKYLIGHT STRUCTURE
DESIGN CALCULATIONS FOR THE SKYLIGHT STRUCTURE I.
General 1. Design Philosophy - PREAMBLE The purpose of this calculation is to verify the supporting structure for its integrity, strength and stability verification. The result of this conclusion is that the structure considered adequate in meeting the required of design criteria. 2. Unit of Measurement Unit of measurement in design shall be in Metric system.
II.
Design Standards 1. Design Code and reference: BS 5950 1190: Structural use of steel work in building Wind loads as per BS 6399 Part 2, 1997 STAAD PRO – Structural Program for calculations. 2. Material Properties The modulus of elasticity of Steel E = 210000 MPa Ultimate Bending stress steel – Po - σ = 275 MPa = 275 N/mm2 Ultimate Tensile Stress steel – Pa = 435 MPa = 435 N/mm2 Ultimate Shear Stress steel – Pv = 0.6X Po = 0.6X275 = 165 MPa = 165 N/mm2 3. Materials Used Main Frame Steel I Beams – JO 102X102 Secondary Frame Support Aluminium Tubes – 50X50X3mm thick All Weld thickness are maintained at 4mm thick
III.
Loadings a. Dead Loads Dead Load – Self weight is considered Dead Load of glass is considered as 55 Kg/m2 Live Load is considered as 0.75 KN/m2
b. Wind loads calculations as per BS 6399 Part 2, 1997: Wind loads (WL) calculated as per BS 6399 Part 2 – 1997: Basic hourly mean wind speed assumed as 27 m/s. Design wind speed Vs = Vb x Sa X Sd X Ss X Sp Where, Sa – Altitude factor = 1.0 Sd – Directional factor = 1.0 Ss – Seasonal factor = 1.0 Sp – Probability factor = 1.0 Design wind speed Vs = Vb x Sa X Sd X Ss X Sp Design wind speed Vs = 27 X 1 X 1 X 1 X 1 Design wind speed Vs = 27 m/s Wind pressure q = k Ve2 K – Constant = 0.613 Effective Wind Speed Ve = Vs X Sb Sb – Terrain and Building factor from Table 4 as Site in town exceeding > 2 KM upwind from the site and 10 KM closest distance from sea at height of 30m, By interpolation, Sb = 1.96 Ve = 27 X 1.96 = 52.92 m/s Ve = 52.92 m/s Wind pressure q = 0.613 x (52.92)2 Wind pressure q = 1717 N/m2 or 1.717 KN/m2 From the above mentioned table,
Cp = 0.7, Net wind Pressure = Cp X q Net windward (front face) wind pressure q = 0.70 X 1.717 =1.202 KN/m2 c. Load Combinations Design & Ultimate factors are considered. as per BS standard, UL = 1.4 DL + 1.6 LL UL = 1.4 DL + 1.4 WL And for deflection, UL = 0.9 DL + 0.8 WL IV.
Design Method 1 Basic data The skylight structure will be loaded considering the overall lengths and widths are 6.260m and 6.840m respectively with a height of 0.50m above level. The glass is placed on the skylight structure with a maximum size of 1560mm X 850mm distributed along the line loads, whereas the steel sections is placed below the glass to support the glass and structure is checked and verified separately below. Loads are calculated on the spacing between the supporting beams i.e. 1.275m which are as follows: Dead Loads: a) Self Weight to be checked from the program b) loading is calculated as 0.550 X 1.275 = 0.701 KN/m Live Load – 0.75 X 1.275 = 0.956 KN/m
Wind Loads: a) Uplift wind load = 1.202 X 1.275 = 1.533 KN/m b) Downward wind load = 1.202 X 1.275 = 1.533 KN/m To check the maximum length of the skylight structure against all the above loading combination and to be on factor of safety (see attached calculations made by the structural program STAADPRO).
Conclusion: All sections used and connections provided are structurally sufficient and meet its intended purpose.
