Multi-storey industrial building. Prefabricated version and monolithic version

I. Design of cast-in-situ reinforced concrete slab

In accordance with the task, it is required to design a four-story industrial building with plan dimensions between the inner faces of the walls L = 34.2 m, B = 27.0 m. Brick bearing walls 510 mm thick. Binding of wall layout axes is taken equal to 120 mm.

Window openings in the building are adopted with a width of 2.3 m, a height of 2.1 m. The height of the floors between the elevations of the clean floor het = 4.1 m. The normative temporary load on all inter-floor floors

vn = 12 kN/m2, including short-term vshn = 1.5 kN/m2. Snow load on the roof vsnn = 1 kN/m2.

Foundation bottom is based on soil with design resistance R = 0.3 MPa. Foundation floor elevation - 1.5 m.

Intermediate reinforced concrete floors are supported by external brick walls and internal reinforced concrete columns. Roofing is supported only by external walls.

Redistribution of bending moments

Due to the stringent requirements for the placement of rebar outlets in the support sections of the crossbar, which are joined by bath welding, it is necessary to strive to reduce the section area of the support reinforcement and the number of rods in the support sections, as well as to unify the reinforcement of the support sections. This is achieved by redistribution of forces between support and span sections due to plastic deformations of concrete and reinforcement in accordance with [6]. At the same time, the reduction of reference moments should not exceed 30% in comparison with those calculated according to the "elastic" scheme. The calculations for redistribution of forces in the continuous girder are summarized in Table 4.

At reduction of reference moment on support B by 30% we accept maximum ordinate of additional triangular epure.

ΔMB = 0.3 MB, max = 0.3MB, II = 0.3· 551.8 = 165.54kN· m, and in order to unify reinforcement of support sections, the moment on support C is reduced to 0.7· MBmax = 0.7MB, II = 0.7· 551.8 = 386.26 kN· m. Maximum ordinate of additional epure = 504.7 - 386.26 = 118.44 kN· m.

Чертеж.dwg