Ladders-architectural structures

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The ladder is a functional and constructive element providing vertical connections. The staircase consists of a series of steps. Usually this term applies to elements of buildings or structures that are the supporting structure. The term is also used for lifting elements of service vehicles (for example, fire), ladders of ships, airplanes and helicopters, rope ladders, garden stepladders, escalators, etc.

The stairs.

Classification of stairs and requirements for them:

Ladders are used for communication between floors or different levels.

By appointment, the stairs are divided into:

1. Basic - employees for permanent use and evacuation;

2. Auxiliary - for service communication between floors;

3. Emergency - external emergency stairs;

4. Fire - are arranged, openly, outside the building.

The design of the ladder consists of alternating platforms and marches.

The march consists of a series of steps supporting their inclined beams and fencing.

Beams are called kosoura (if the steps rest on them from above) and with a string (if the steps adjoin them from the side).

Bearing elements of the march are based on the bearing elements of the site - areal beams (Fig. 100, 101, 102)

Landings are floor (located at the level of floors) and intermediate.

The upper and lower stages of the march, which serve as a transition to the sites, are called frieze.

Depending on the number of marches within the height of one floor of the staircase, there are single-mid, double-mid, and three-mid-flight ones. Most often used dvuharshevye. With a three-march ladder between marches, it is convenient to locate elevator shafts.

In residential buildings up to 5 floors, a staircase leading from the upper floor level to the attic is arranged in the form of a steel step ladder. Over 5 floors of stairs leading to the attic, are a continuation of the main.

Depending on the material used, the stairs are :

1. wooden;

2. prefabricated reinforced concrete (or stone) steps on metal supporting structures;

3. whole reinforced concrete - prefabricated and monolithic;

4. steel.

Wooden stairs are used in stone buildings of III and IV class, up to 2 floors.

Stairs with metal bearing structures and monolithic reinforced concrete stairs in order to save metal and industrialization are allowed to be used only in public buildings with a complex form of stairs (Fig. 105).

Precast concrete stairs are used in mass construction of typical residential and public buildings.

Steel make emergency stairs and firefighters (Fig. 100, 101, 102, 107, 108,109)

Constructions of stairs.

1. Stairs on steel beams:

Carried out with reinforced concrete steps. Steps made of natural stone, such as granite, are used mainly for outdoor stairs and for stairs with particularly heavy traffic (fig. 105, 106).

2. Reinforced concrete stairs:

Monolithic reinforced concrete stairs: these stairs are very durable, but require complex formwork and delay the construction progress. Therefore, they are used very rarely.

Precast concrete: a ladder of small-sized elements: the connection is achieved by welding the embedded elements. Steps stacked on kosouram on cement mortar. Fences made of steel posts (embedded in steps) and inclined gratings.

Reinforced concrete stairs made of large-sized elements are very widespread. Elements (marches and platforms made at the factory) of the stairs are installed in place by the crane and fastened with welding of embedded parts. Such stairs are made either with textured surfaces of steps and platforms or with patch treads (fig. 106, 107, 109).

In the stairwells there should be no storage or other purpose premises, exits from the mines of forklifts, industrial gas pipelines and pipelines with flammable liquids.

For a sufficient passage in the staircase raise the level of the floor of the 1st floor above the level of the floor of the entrance area by 0.5-1.0 m (Fig.101).

Basic requirements for ladders.

It is traffic safety and convenience of walking on them. For this purpose, in addition to ensuring the strength and rigidity of structures, when designing stairs, it is necessary to observe a number of rules .

The slope of the march should be taken according to the SNiP (depending on the purpose and number of floors of the building) for the main stairs 1: 2 - 1: 1.75, and for the auxiliary up to 1: 1.25; All steps in the march should be the same size, comfortable for walking. Where possible, marches should be unified. The number of steps in the march is assigned not more than 18, but not less than three. Usually marches have from 10 to 13 steps.

Marches and grounds are guarded by railings of 0.9m height; the height of the aisles under the grounds and marches is made at least 2 m; stairwells should have natural light.

The width of the staircases is accepted according to the fire requirements of at least 0.6m per 100 people. Where there are elevators, the requirements are different.

The width of the landing area must be at least the width of the march.

For residential floors of 10 or more floors, there should be at least two escape routes or a device of so-called “smoke-free staircases” is necessary.

Stability of the staircase is ensured by the creation of an open air zone in the form of a balcony or loggia when entering it, which prevents the spread of smoke to other floors of buildings. At the same time, instead of two ordinary ladders, one can be designed one that is not smoked (fig. 111).

Another technique: the creation of an artificial air suppression that prevents the penetration of smoke into the stairwell; carried out ladders are communicated through a cold gateway.

In the stairwell, exterior entrance doors open to the side of the exit from the building. Entrance doors to the apartment with the stairs must be opened inside.

The steps of the stairs are divided into privates and friezes , adjacent to the sites; upper and lower frieze steps.

The horizontal plane is called the tread , the vertical plane is the riser . Step height 130-200mm, width not less than 250mm.

The strength and reliability of the interfaces of prefabricated reinforced concrete structures of stairs is achieved by welding of embedded parts that are placed in the connected elements, respectively, one against the other.

Domestic stairs are arranged wooden . Separate steps are stacked on kosoura or cut into the bowstring, starting with the lower frieze and ending with the upper frieze. Fencing stairs also perform wooden.

In the internal stairways allowed the device zabezhnyh steps and spiral staircases .

Fire and emergency stairs in public and residential buildings are carried out.

Fire escapes to the roof are made straight and are not adjusted to the ground level by 2.5 m. The width of the fire escapes is taken at least 0.6 m.

Emergency stairs are structurally similar to firefighters, but additional requirements are placed on them: the slope of the stairs should be no more than 45 °, the width should be at least 0.7m. On each floor there are special areas.

Ramps . For communication between the various levels and floors in public buildings, along with the stairs, ramps are used - flat inclined structures without steps. They are given a slope of 5 to 12 ° (1/12 - 1/5). With large slopes, using a ramp is difficult due to slipping. Ramps with a small incline cause large losses of the usable area of ​​the building. Clean ramps should have a non-slip surface (asphalt, cement, reel, mastic, etc.).

Elevators and escalators . They relate to mechanical devices for organizing communications between floors. The most widely used elevators periodic (intermittent) actions. Depending on the requirements, they use cabs with one entrance to the elevator or cabs with the location of entrances from opposite elevator shafts.

The machine room of the elevator may be above the shaft (top location) or below it (bottom location).

The elevator shaft should not adjoin the living space directly; locate the engine room of elevators directly above and below the living space, as well as adjacent to them.

Currently, the so-called outdoor elevators of the suspended structure, which are used in residential buildings of the old building, in public buildings for various purposes, have become widespread.

Elevators, low speed, continuously operating (not stopping) are called paternosters .

An escalator is a moving staircase; to the class of lifting devices of continuous action. Buildings often use multi-marsh escalator layouts.

A single-flight escalator consists of tensioned chain steps supported by supporting inclined metal trusses. Traction chains and steps, each of which moves on four sliders, form an escalator canvas. The upper branch of the canvas is working, and the lower - idle.

The design includes moving handrails, height 90cm. The most common are escalators with a web width of 0.6 to 1.0 m. The angle of inclination of the web can be arbitrary, but not exceeding 30 degrees. Escalators in the building should be duplicated by ordinary fire safety ladders.

LADDER CELL 2x-3x - FLOOR HOUSE WITH CROSSBOW CARRIER BRICK WALLS

Fig. 100.

CROSS SECTION

DRYWEAR LADDER FROM REINFORCED CONCRETE MARCHES AND PLAYMENTS (PLAN OF THE 1st FLOOR)

Fig. 101.

REINFORCED CONCRETE LADDER MARCHES WITH FOLDED STEPS

REINFORCED CONCRETE LADDER MARCHES WITH EMPTY STEPS

Straight single martyr

TWO GIRLS

WITH CROSS-MARCHES

Fig. 102

INTERIOR STAIRS

ONE MARBLE

TWO MARRHE

a - tread size

in - the size of the riser

Notes:

1. internal staircases must satisfy the formula 2 b + a = 60-64 cm; size 60-64cm - the size of the average step of a person.

2. The recommended slope of the stairs is 1: 1.5, which corresponds to the ratio b : a = 16.6: 25 (the maximum slope of 1: 1.25 cm is allowed).

3. In parentheses are given the dimensions for the slope 1: 1.25.

4. The minimum width of the march is 90 cm.

5. the height of the passages under the flight of stairs to the bottom of the protruding structures is not less than 200 cm.

INSIDE

WITHOUT SECURITY STEPS

WITH SECONDARY STEPS

Fig. 103

WOODEN LADDER

WITH SECONDARY STEPS

WOODEN TWO-SUSPED LADDER

TWO-WOOD WOODEN LADDER

Fig. 104.

WITH REINFORCED CONCRETE STEPS

AND REINFORCED CONSUMPTIONS

TOP 12 LAND SUPPLY AREA

STAGE UPPER FREEDOM NEED - 11

FROM REINFORCED CONCRETE

AND KOSOUROV

PLATING PLATE OF THE TOP PD-11 AREA

STEP MAIN CO-11

STEP LOWER FREEDOM CH-11

COSOUR

SUBSCRAPED BEAM K 26

WITH REINFORCED STEPS AND STEEL COWSERS

Fig. 105

LADDERS FROM SMALL DIMENSIONAL ELEMENTS FOR LOW-ESTABLE BUILDINGS

WITH REINFORCED STEPS AND STEEL COWSERS

UPPER FREEZE STEP

WITH RELEASE FOR INTERMEDIATE PLATFORMS

WITH FOURTH AND INSERTS FOR UPPER SITE

STEPS:

LOWER FREEDOM

ROW

Socle

BASEMENT

KOSOUR AND SUBCOLOR BEAM

FROM REINFORCED CONCRETE SPECIES AND COUPLERS

FROM WOODEN MARSHES ON TITES

Fig. 106

LADDER MARCHES AND PLATFORMS FOR THE FLOOR OF 2.8 m HEIGHT.

RIBBED CONSTRUCTION MARSHI U-SHAPED,

FULLY CABLE, WITHOUT FREEZE STEPS

MARSHI T-SECTION, WITH FREEDOM STAGES

MARSHI P - CUTTING SECTION WITH FREEDOM STEPS AND BACKWARDS

Fig. 107.

SERVICE STEEL LADDERS (SERIES 2.150-1) AND ACCESSORIES

ATTIC

OUTLOOK STEMYANKA, HANGED TO HATTED FRAME

IN THE UNDERGROUND

TILTED STREET

VERTICAL STRAEMYAN WITH HANDRAIL

OUTLOOK STEMYANKA ON STANDS

FROM THE ROOF OF THE BUILDING ON THE ROOF OF THE MACHINE ROOM VERTICAL STEMYANKA WITH HANDRAIL

TILTED WEDGESTONE

STEEL GRID FOR CLEANING SHOES

Fig. 108

LADDERS

WITH P - SHAPED MARCHES

WITH P - SHAPED FOLDERS MARCHES

WITH N - SHAPED FOLDING MARCHES

WITH T - SHAPED FOLDING MARCHES

MARCHES OF PLATE CONSTRUCTION

1-roller; 2-tail; 3 - bed;

4 - castle

Fig. 109.

LADDER-ELEVATOR DIRECT LINK LINK

9TH FLOOR PANEL RESIDENTIAL HOUSE

Fig. 110.

LADDER-ELEVATOR DIRECT UNIT 12-16 - FLOOR PANEL RESIDENTIAL HOUSE (BY SERIES 137)

Fig. 111.