ladder Calculation . At height of 3300 mm the ladder should be two-mid-flight. Width of a march define so. From width of a staircase (3000 mm) subtract an interval between the marches, equal 100 mm, and divide the rest on 2, receive (3000-100):2=1450мм. The height of each march will be equal to floor height (3300 mm), delennogo on 2, i.e. 3300:2=1650 mm. /
The Size of steps accept equal 150x300 mm (150 mm - height). Quantity podstupenkov in each march define division of height of a march into height podstupenka, i.e. 1650:150 mm=11 pieces of Prostup of the top step of each march coincide with a platform surface, and it means that prostupej will be on one less, i.e. 10. Therefore each march will consist from 11 podstupenkov and 10 prostupej.
Knowing width appear (300 mm) and quantity of steps (10), it is possible to define a horizontal projection of a march, its length or as speak, zalozhenie a march; for this purpose width appear multiply by quantity of steps: 300x10=3000 mm. The width of each platform is provided to equal width of a march, i.e. 1450 mm. Under the executed drawing of a ladder on walls mark platforms, a bowstring and steps. In the bottom of a wall measure width of platforms (on 1450 mm), and from them - width appear (on 300 mm). /
On the received marks by means of a plumb and namelennogo a cord spend strictly vertical lines. Then at level of a floor of the ground floor spend a horizontal line, from it measure 150 mm and spend the second horizontal line, defining prostup the second step, etc. Last, 11th, prostup should be flush with a platform floor.
On breakdown produce a plywood or board template with which help mark a bowstring: find position of beams under a platform and bruska (logs), a floor of the ground floor stacked at level. The staircase bowstring will lean against these beams and brusok. /
If beams of ladder platforms lean on rublenye walls, it is necessary to provide, that after deposits of walls of a platform remained flush with wearing floors. Therefore nests in walls do above, than height of beams, on 100 mm, and under beams
Put racks. After rack deposits clean, and beams fix.
a Fig. 50. A board ladder :
And, - connection of bowstrings of a ladder with a beam; in - interface appear with a bowstring;
1 - ladder bowstrings; 2 - appear; 3 - a beam; 4 - a cross-section beam; 5 - a steel square; 6 - rejka; 7 - a wedge; 8 - a rack; 9 - basic rejka; 10 - boards; 11 - a board nakata; 12 - a clay layer; 13 - sound insulation; 14 - a deal floor; 15 - a ceiling; 16 - rejka; 17 - plaster on a shingle; 18 - nashchelnik.
It is possible to do Ladders with zabezhnymi steps, i.e. screw. Space under staircases use under pantries. By the same principle build ladders and of concrete. It is necessary to remember that concrete or ferro-concrete ladders do in stone, brick, concrete and to that similar buildings or walls specially arranged from such materials for a staircase. These ladders can be monolithic or modular. For the first do a timbering, for the second - the form. The timbering should be established strongly that under weight of concrete could not sit or collapse.
That products were pure, it is recommended a timbering and forms from the working party to do stroganymi, and boards - skintight to each other. It will prevent vytekanie through cracks of cement milk. And it too work of the carpenter. Before pouring of the form and a timbering it is necessary to water well. From board water extend, condensed, cement milk does not spill, and boards do not absorb a moisture which is necessary for the best tverdenija the last from concrete. /
To give to concrete high durability, into it insert prutki steel armature, receiving ferro-concrete. From ferro-concrete more strongly, easier and it is less than product on the overall dimensions. Ladders can be completely concrete or combined: beams and bowstrings concrete or ferro-concrete, steps and a flooring - wooden. For tree fastening to concrete in products it is necessary to insert wooden stoppers-churochki into concreting time, having them in corresponding places into which then drive in nails.
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