TECHNOLOGY FOR INSTALLATION OF REINFORCED CONCRETE FLOOR SLABS LIGHTENED BY CORE DRIVERS WITH PRELIMINARY REINFORCEMENT STRESS

The paper presents technology for installation of floor slabs lightened by plastic core drivers which are preliminary stressed under construction conditions.  Efficiency of such constructive solution is justified by the action of preliminary concrete compression in the tensile zone while reducing structure dead weight due to void arrangement.  The paper provides classification of systems for preliminary stress and contains recommendations on selection of the system depending on peculiariar features of the designed construction.  Main products and materials required for execution of works , requirements to stressed wire rope reinforcement, its main characteristics have been considered in the paper.

Principal diagram of the lightened preliminary stressed slab stipulates arrangement of so called  dummy caisson. Strands of reinforcement ropes are located within the framework of bars passing over supporting structures (over vertical bearing structures of  the framework) and voids are formed in the cells between bars by laying hollow plastic items joined together by a cage. The paper presents technological sequence of operations required for arrangement of the lightened preliminary stressed slab, schemes for equipment arrangement and characteristics of the applied devices and units (pushing device for reinforcement ropes, hydraulic jack with delivery hydraulic pump, mixing station, injection pump and others).  Recommendations have been given for execution of works in cold weather. The paper considers problems pertaining to control quality of the materials and items which are supplied to a construction site and directly execution of works on preliminary stress of a cellular slab.

The executed analysis of technology permits to conclude that it is characterized by high level of applicability for import substitution. It is necessary to consider the possibility to apply the technology at objects of various application while comparing it with other constructive solutions according to the main technical and economic indices. 

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