Technology map for concreting floor slabs

The technological map is developed for concreting floor slabs. 

Regulatory documents: SP 435.1325800.2018. "Concrete and reinforced concrete monolithic structures."; SP 70.13330.2012. "Load-bearing and enclosing structures."; SNiP 12-03-2001. "Occupational safety in construction. Part 1. General Requirements."; GOST 21.101-2020.

Initial data: The building is monolithic reinforced concrete frame. Dimensions in plan: 29.4x19.44 m2. The exterior walls are made of monolithic reinforced concrete with a thickness of 400 mm. The grillage is 800 mm high with dimensions in plan 29x19 m, the number of piles is 390, with a step of 1.2 m. The floors are reinforced concrete monolithic, 200 mm thick, and the external insulation is 100 mm thick polystyrene foam. 

Duration of construction according to SNiP 1.04.03-85* Part II. The norms for the duration of construction are 16 months. 

1. Tower crane: In the course of this work, a crane was selected for the construction of the building: by lifting capacity (4.5 tons), by boom lifting height (78 m), by boom reach (27.44 m). A swivel  bucket (BP 2.0 – 4.5 tons) was adopted as a load-lifting element. Two cranes were selected: a domestic tower crane of the KB-504.2 brand. (320.000  rubles per month); foreign fast-erecting tower crane POTAIN  K-40 (France) (1.008.000 rubles / month).
2. Choice of formwork system: Formwork for floor slabs on telescopic posts was adopted, as its main advantages are: 

• Easy installation that can be handled by two people;
• The ability to adjust the height of the posts, because of this, they will fit any ceiling height;
• It is possible to install floor formwork in any areas: steps, inclined surfaces.

The main components of the formwork: plywood (laminated, which repels moisture), telescope posts for formwork support, I-beam (200 mm high), uniforks, tripod (provides vertical fixation of the posts).

1. Calculation of the scope of work: it was chosen by the GESN for the installation of beamless floors with a thickness of 200 mm.
2. Selection of the main equipment: 

• For the delivery of concrete mixture – concrete mixer truck (CP 120, mixer volume 3.75 m3)
• For the supply of concrete mixture - a stationary concrete pump, since it is designed for the construction of multi-storey buildings, the supply of concrete mixture can be carried out up to 150 m vertically, 450 m - horizontally. Brand: CIFA (Italy), model PC-907, feed height – 120 m.
• For concrete mixing, the hydraulic concrete spreading boom (JAINE HGY 21 m – maximum horizontal dispensing radius) is used: it is possible to save manpower, reduce the length of the pipeline.
• For compaction of concrete mixture – manual deep electric vibrator with a flexible shaft IV-47, according to clauses 9.3.14 - 9.3.21.[ SP 435]: compaction of the concrete mixture is carried out with the help of a deep vibrator.

9.3.17: Immersion of the deep vibrator in the concrete mixture should ensure its deepening into the previously laid layer from 5 to 10 cm.

• To lift workers and construction material to the maximum height of the building - a truck construction lift TP-17 (lifting capacity = 500 kg, loads up to 5 m long).

1. Effective additives for cement concrete: 1. Antifreeze additive - "LIGNOPAN B-4" antifreeze – plasticizing additive (up to -20 C), 2. Superplasticizer – "POLYPLAST SP – 1VP", 3. Plasticizing additive - "MEGALIT S-Z ML".  In the course of comparing the last two supplements, the second one is preferred, as it is the most profitable option.

Further, the technology and organization of work were described in detail: formwork, reinforcement, concrete in accordance with SP.435. "Concrete and reinforced concrete monolithic structures".