Prefabricated reinforced concrete structures are most often used in single industrial halls- and multi-bay, mainly due to the high demand of this type of buildings, industrial production and facilitating their execution on the construction site. Prefabricated elements can be used to make halls not only of simple shapes, and also about complex (entertainment halls, sports and others). In industrial halls, column-beam and column-truss structures are most often used.
The load-bearing structure of this type of halls are:
a) foundations (the most common footings),
b) one poles- or two-branch,
c) roof girders or trusses,
d) cover made of reinforced concrete or sandwich panels,
e) crane beams,
f) longitudinal and transverse braces,
g) external and internal walls,
The span of the halls depends on the elements used for the covering; the halo covered with beam girders have spans 12-30 m, while the halls are covered with lattice trusses 12-60 m. Reinforced concrete roof girders are used for smaller spans, for the larger ones, compressed.
There are many types of roof trusses and girders (roof beams) used as hall covers.
Lattice trusses are used mainly to reduce the weight of the roof and save materials: concrete and steel. The shape of reinforced concrete trusses is similar to that of steel trusses. The height of the trusses is assumed to be h = (1/7 – 1/10) l (l - span).
Due to the possibility of transport, the length of single-segment trusses does not exceed 30 m. Above this length, trusses made of segments and joined, most often by prestressing at the construction site, are used. Multicore cables are used for stressing. Due to the assembly, reflex trusses are particularly advantageous, because there is no need to use vertical braces.