Ladders serve for the message between floors, and also evacuations of people from a building. They consist of marches, ladder platforms and a protection with a handrail. Ladder platforms at level of each floor name floor, and platforms between floors - intermediate. For lifting from porch level on the ground floor arrange a short socle march. A premise in which place a ladder, name a staircase.
The March represents a design consisting of steps and beams supporting them. The beams which had under steps, name kosourami, and beams which steps adjoin sideways, - bowstrings.
On an arrangement in a ladder building can be external and internal, and to destination - the cores, spare, fire and emergency. Emergency and fire-escapes, and in southern areas and ladders of small buildings arrange outside, without staircases.
Quantity of ladders in a building and their sizes depend from etazhnosti buildings, intensity of a human stream and the requirements of the fire-prevention safety shown to the given building. In residential buildings in height more than ten floors suit nezadymljaemye ladders. Their staircases have the doors leaving on balconies or loggias. Big, developed on width, with big otnosom from a building and earths a little raised over level ladder-porch front doors name stilobatom.
By quantity of marches within one floor of a ladder subdivide into one - two- and three-mid-flight. Two-mid-flight ladders are most extended. A vertical side of a step name podstupenkom, and horizontal - prostupju.
Distinguish wooden ladders, ladders from separate stone or ferro-concrete steps on steel kosouram, monolithic and modular ferro-concrete, steel. The inclined planes connecting instead of usual ladders floors or adjacent premises with different levels of a floor, name ramps. In some premises apply spiral staircases.
a Fig. 48. Fragments of wooden ladders :
And - knot of a ladder platform; - a connection detail appear with podstupenkoj; in - a ladder with the steps beaten to bruskam; g - a wooden step-ladder; d - wooden hand-rail; 1 - ploshchadochnaja a beam; 2 - bowstrings; 3 - prostup; 4 - podstupenok; 5 - filing; 6 - a plinth; 7 - a floor; 8 - sand or slag; 9 - nakat; 10 - a protection rack; 11 - the garret hatch; 12 - a step-ladder; 13 - welding; 14 - the top draught; 15 - a screw; 16 - a wooden hand-rail; 17 - brusok
Wooden ladders (48-50) apply fig. mainly in wooden buildings, is more rare - in stone in height to two floors and if the building is not fire-dangerous. As bearing elements of wooden ladders of 60-80 mm serve ploshchadochnye beams and bowstrings in the thickness. For interface of steps to bowstrings on a lateral surface of bowstrings choose grooves into which insert the ends of boards prostupej and podstupenkov.
Ladder platforms of wooden ladders can be with an unary floor, with a floor and ceiling filing, with a floor and nakatom, with zasypkoj and without zasypki, with plaster of a ceiling and without it. From below marches can have board filing which sometimes plaster.
Before an input in the house usually equip a porch (an easy canopy) with a ladder which can be from a tree, concrete, ferro-concrete, metal. Their components are inclined marches and horizontal platforms. Marches consist of bowstrings (inclined bruskov), steps and a handrail. The width of a march (length of a step) fluctuates from 120 to 145 sm, in basements and attics makes 80 the Width of a bowstring see its thickness - 6-7 sm (fig. 49 and 50) depends on the sizes of steps. /
Porch Steps consist of two separate parts - appear (width of a step) and podstupenka (step height). Width 27-32 sm, height podstupenka 15-18 appear see Appear do of one or two boards in the thickness of 40-60 mm, podstupenok - from one board in the thickness of 20-25 mm. It is necessary to remember that the more low podstupenok and is wider prostup, the it is easier to walk upstairs.
Details of wooden ladders krepjat on nails, screws or thorns. Hand-rail in premises it is possible krepit to baljasinam in addition glue.
a Fig. 49. The porch device :
And - a general view; - the porch device; in - wooden steps; g - a bowstring and it opiranie on a bar; d - baljasnik;
1 and 10 - a bowstring; 2, 5, 6 - bruski; 3 - lezhni; 4 - chairs; 7 - a flooring; 8 - appear; 9 - podstupenok; 11 - lezhni; 12 - chairs; 13 - a hand-rail; 14 - a curbstone.
At the ladder device (fig. 49) it is necessary to prepare a corresponding material first of all. Then dig poles, put there chairs, cover them with earth and stamp it. Cut off top of chairs strictly at one level, do on them zapily for thorns and choose a wood part (all can be made it and in advance). In lezhnjah (logs) hollow nests and put on them thorns. To level it is inexact the laid logs, to them nails or cutting krepjat bruski. Then produce a bowstring, krepjat it to lezhnjam, beat a flooring and steps. /
Boards appear is better to connect in a thorn, podstupenok with prostupju also it is necessary to fasten a thorn. Bowstrings can be the most various. Most simple of them - a board with the cut out ledges, and the strongest and difficult in manufacturing - with vrezannymi in it steps (fig. 49).
Bowstrings with vrezannymi steps is better to gather at once, i.e. in a march, and in the collected kind to establish a march. Bowstrings it is possible krepit differently. We will consider the most simple way. To ploshchadochnoj to a beam krepjat a board with corresponding cuts - grooves into which insert bowstring thorns. Fix thorns in a board nails or steel strips, skobami. /
Having made steps and a platform, start protection manufacturing. First of all put curbstones, mark and hollow nests in prostupjah and hand-rail for baljasin in which do thorns. The form baljasin and hand-rail can be various. Krepit them it is necessary so that neither curbstones, nor a protection did not shake. From sides the porch and curbstones is recommended to be boarded. To protect a porch from a rain and snow, over it arrange a peak (roof).
The Wooden ladder in the two-storeyed house consists of one or several platforms and marches. The top and bottom steps of each march are called frizovymi and differ under the form from the others a little. Platforms can be floor which equip at level of a floor of each floor, and intermediate, arranged between floors.
Each march consists of beams or kosourov, supporting steps and a protection from a handrail. The ends kosoury lean on ploshchadochnye beams or against staircase walls. If do a two-mid-flight ladder, and under a platform there is an exit on street between a platform and a ground floor floor there should be a distance not less than 2,1 m. /
In building practice the certain sizes of elements of ladders are accepted. Steps the size 150x300 the mm, i.e. step height - 150, width - 300 mm more often have. These sizes allow suit a march bias in the ratio 1:2. The width of a ladder should be not less than 1200 mm, width of platforms - not less than width of a march. The quantity of steps in one march fluctuates from 5 to 18.
Correctly to define necessary quantity of steps, it is necessary to construct first of all a staircase graphically on a sheet of paper strictly on scale or in nature on a wall. We will consider it on a following example. In the two-storeyed house the staircase in length of 5900 mm, width - 3000, by height from level of a floor of the ground floor to level of a floor of the second floor - 3300 and distance between marches of 100 mm (fig. 49) is provided.
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