The trusses spacing for 6m prestressed bow string truss with cable reinforcement span for 18m material requirement per truss prestressed bow string truss with cable reinforcement span 24m-steel 621-689, 30m-steel 1041-1219.

If precast roof slabs are used for roof covering upper chord panels are made equal to width of precast slabs which is usually about 3m and lower tension chord is prestressed using bunched high strength wires or cables running in perforated holes.

The aim should be to use lowest percentage of fine aggregates which is consistent with job conditions and which will permit placing of concrete without honey combs and finishing it to a satisfactory surface and for high strength concrete used for prestressed concrete structures, degree of workability as categorized in Indian standard code IS: 456-2000.

b_w is 200, d is 1750, f_ck is 60n/mm², b is800, D_f is 400,
M_u = 0.176bwd²f_ck+2/3 x 0.8(b-bw)(d-0.5D_f)D_ff_ck = ((0.176x200x1750²x60)+0.67�0.8(800-200)(1750-0.5�400) 400�60) = 18253�10⁶nmm.

N_d = 377�10³, ? = 0.18, f_ct = 15n/mm²
Area of concrete section = (N_d/?f_ct) = (377�10³)/0.8�15) = 3.316mm².

The world?s tallest and longest cables stayed bridge is located in France and French bridge is considered to be an engineering feat since some of bridge pillars rise gracefully to a height of more than 300m and bridge is located outside French town of milliance and is 2.46km long and bridge designed by famous British architecture sir norman Foster, is currently world?s tallest and longest cable stayed bridge and described by many as an astounding engineering feat.

At ends of trusses near supports, 10-12mm steel bearing plates are anchored and embedded while casting, which serve as bearing and for fixing trusses on neoprene pad bearings located on columns.

The precast prestressed I and inverted T beams have been standardized by cement and concrete association for use in construction of bridge decks of spans varying from 7 to 36m and standard I and T units are widely employed in highway bridge beams in USA.

The use of concrete trusses with modular coordinates for spans of 6,9,12,15,18,24,30 and 36m with a base module of 30m is most common for industrial buildings of east European countries such as Russia, Poland, Slovakia, Germany, Branko zezelji has reported construction of reinforced concrete wit prestressed tie members for spans up to 60m in erstwhile Yugoslavia.

Prestressed hollow inverted pyramids have been used as a transfer: Girder system to support four storey complex housing administration building for engineering construction corporation limited at manapakkam in madras and upper four storeys housing administrative complex rest on four hollow prestressed pyramids which in turn are supported on hollow core walls.