Instructions for correct application

Introduction

This instruction provides information on correct means of relocation and installation of items from the point of view of maximal safety and prevention of accidents guaranteeing integrity of the items.

The installing company shall be guided by the instructions given below and the manager of the works shall control their observation.

All the works shall be carried out by experienced and qualified personnel under the supervision of monitoring or responsible people, with complete observation of safety norms and using corresponding equipment.

Apart from the given instructions for all operations related to relocation, installation and arrangement, it is necessary to use normative acts on safety in the workplace and temporary construction sites. If these instructions are not observed, the producing company shall not be responsible for the damage caused by the items to other items and/or people.

Types and description of possible cutouts, made in a hollow core slab

Type of cutouts

А – a cutout with the width up to 40 cm, which shall be located in the distance not less than 30 cm from  a longitudinal part of the slab. If the length of the cutout is more than 50 cm, it is necessary to use lateral enforcement -a1- and longitudinal -a2-. It is necessary to inspect impact of lateral power.

В – a hole, located along the length of the slab hollow with the width not exceeding its diameter, does not need any inspection.

С – a hole, located along the length of the slab hollow with the width not exceeding its diameter, does not need any inspection.

D – a cutout with the width not more than 40 cm. It is necessary to carry out lateral enforcement -d- and inspection on lateral power.

E – a cutout, when the length of each of its half shall not exceed 40 cm. It is necessary to carry out lateral enforcement -e- and inspection of the slab’s bearing capacity.

F – a cutout with the width made in accordance with the size of column -P-, where its largest side end -F- shall rely on the cantilever of column -p- in pinned manner.

G – a cutout when its size is less than 40х40 cm and additional measures for enforcement are not needed, except when inspecting on lateral power.

H – a cutout when its width is less than 20 cm and additional measures for enforcement are not needed, except when inspecting on bearing capacity of the slab.

I – holes in-situ under pipelines, etc. It is necessary to inspect the bearing capacity of the slab upon termination of longitudinal enforcement.

L – holes, radius of which shall not be more than 40 cm, are made in  unset concrete. It is necessary to inspect remaining bearing capacity of the slab.

M and N – holes, width of which shall not be more than 30 cm. If the length is more than 60 cm, it is necessary to arrange additional enforcement -n n-. The given type of holes can be made in-situ with the help of a diamond disc. It is necessary to inspect the remaining bearing capacity of the slab.

Typical details of slab application

Relocation and lifting of slabs

Manoeuvers related to relocation and lifting of slabs shall be carried out so that to avoid knocking and jerking in compliance with the safety norms on working with hanging loads and lifting mechanisms; load lifting hooks, equipped with locking mechanisms, shall be able to bear the load of industrial items.

Slabs shall not be relocated in windy weather when the velocity of the wind exceeds 60 km/h.

When slabs are being relocated and lifted the workers shall be in a safe distance from the working radius of the item so that, in the case of possible unhooking of the slab, even from one side, it does not injure people.

The safety ropes shall be unhooked only when the slab is in the distance of 10 cm over the place of support.

As a rule, slabs shall be lifted in compliance with the following schemes. In special cases, instructions on lifting are given on a special drawing.

The system of strapping for relocation with flat polyether slings with necessary resistance – the flat slings will be equipped with necessary connecting mechanisms: a steel plunger from one side and a loop on the other end so that throttle strapping is possible.

Transportation of slabs

While transportation in compliance with the effective Traffic Regulations the slabs shall be arranged in stacks and supported by a wooden log; besides, they shall be firmly fastened to the vehicle by means of special ropes in compliance with the norms, regulating safety while transportation.

Storage of slabs

Stack of slabs, located on a special plank, shall consist of the elements with extending length from bottom to top; they shall be arranged far from passages on firm horizontal surface (permitted error 5 cm/ 5 m) and shall not be more than 2,5 m high. The slabs shall be stored on the crossing of the plank arranged vertically and horizontally.

The manufacturer emphasizes the importance of such storage conditions in order to maintain their integrity.

Installation

Before installation of the item, it is necessary to inspect the underlay, which should be clean and fully complanar with the inner surface of the slab.

Then the slabs are arranged and additional reinforcement is installed at supports, distribution reinforcement and reinforcement of negative moment are also installed: on this stage the covering (structure) is necessary to clean and wet sufficiently.

During installation works, the workers shall not stand under the entire area of the covering.

Concrete casting

Final concrete casting is carried out at the temperature above 0°C and is made of a single matrix, avoiding local accumulation of it; after vibrotreatment and ramming the slab should remain wet for, at least, 3 days.

Longitudinal seams between the slabs and possible hackings should be sealed with the concrete with granulometry not more than 12 mm; the consistency class shall guarantee complete sealing of seams and characteristics shall allow avoiding of formulation of cracks. During concrete casting, standing under the entire area of the covering is strictly prohibited for workers.

Instruction

If the project does not indicate anything otherwise, SLABS SHALL BE INSTALLED ON BEAMS AND/OR ON BEARING WALLS.

On columns-supports there are considered lug supports for supporting hollow core slabs. Prior to arrangement of coverings it is necessary to make sure that the supports are smooth and fully complanar with inner surface of the slabs. If there are no above mentioned conditions, it is necessary (at the client’s expense) to cover the supports with the matrix or rubber tape with relevant technical characteristics and corresponding sizes.

As the slabs of pre-stressed reinforced concrete represent an elevation, a designer and client shall take into consideration that it is necessary to determine a finished floor level and thickness of the support of a possible covering with a fixed formwork. Permitted threshold of arrangement of slab supports is +/- 10 mm.

If average depth of a slab support on the construction area is less than:

• 40 mm for spans up to 5 m
• 50 mm for spans from 5 to 8 m
• 60 mm for spans from 8 to 12 m
• 80 mm for spans over 12 m

it is necessary to brace slab side ends till maturing of additional concrete.

Height differences, exceeding the indicated permitted threshold, can be adjusted by the client up to sealing of cracks with the help of a special patch plate or cross-bar (see the scheme).

An example of a tie-bar and an example of a circular steel cross-bar Ø16 for decreasing the height differences.

Application and servicing

The item should be applied for intended purpose and correspondingly serviced, as it is envisaged in the project; the structure shall be protected from temperature fluctuation, atmospheric and other aggressive impacts with the help of special means, such as plastering or special covering.

The loading determined under the project shall not be exceeded in any case.

Values of loadings and slab spans can be increased in the following cases:

• arrangement of a monolith layer on the slab;
• partially restrained or continuous covering;
• additional lateral reinforcement on a slab support.