Triangle is the stablest structure than polygons !!! As far as less number of sides and angle...the more stable it be...If a truss has size of square,they structure collapse because of the more angle in each side tends to make the structure bend.. read more

Trusses can't bear the wind loads & upthrust loads directly.Beacuse of the loads coming on the trusses the members of trusses got bended & because of which the structure will got damaged or it may fails. Hence,triangle is the need of trusse. read more

Real-world trusses can’t be optimized the way a balsa wood bridge can, because real-world trusses have to carry many different combinations of load, and a truss optimized for one set of loads won’t be optimal for another set. read more

Source: makezine.com

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