1, running the stairs alone is the easiest, suitable for buildings with low floors; Double running stairs are the most common, including double running straight up, double running twists and turns, double running folding (parallel) and so on. , suitable for general civil buildings and industrial buildings; There are three-fold stairs, T-shaped stairs and split stairs. , mostly used in public buildings;
2. Scissors staircase consists of a pair of parallel double running ladders with opposite directions, or a pair of single running straight ascending ladders which overlap each other but are not connected, and the cross section is scissors-shaped, so that more people can pass through and space can be saved;
3. The spiral staircase is supported on the middle column and has fan-shaped steps. Although it is uncomfortable to walk, it saves space and is suitable for places with few people and infrequent use.
4. Round, semi-circular and arc stairs, supported by curved beams or plates, with slightly fan-shaped steps, diverse and fancy styles, lively shapes and rich decorations, are suitable for public buildings.
Extended data
Stairs are divided into ordinary stairs and special stairs:
Ordinary stairs include reinforced concrete stairs, steel stairs and wooden stairs, among which reinforced concrete stairs have many advantages in structural rigidity, fire resistance, cost, construction and modeling, and are most widely used.
2. There are three kinds of special stairs: fire escape, fire escape and escalator.
First, ordinary stairs
According to the material, it can be divided into reinforced concrete stairs, steel stairs and wooden stairs.
1, reinforced concrete stairs
It has many advantages in structural rigidity, fire resistance, cost, construction and modeling, and is widely used. There are three construction methods for reinforced concrete stairs: integral on-site pouring, prefabricated assembly, partial on-site pouring and partial prefabricated assembly:
The integral cast-in-place structure has good rigidity and is suitable for buildings with special requirements and high seismic requirements, but the formwork cost is large and the construction period is long. There are three kinds of prefabricated stairs: large, medium and small.
Large-scale is to prefabricate the whole step and platform into a component; The medium-sized one is to prefabricate the steps and platforms into a component, which is widely used; The small one is to prefabricate the inclined beams, steps, platform beams and plates of the stairs into small components, and connect them into a whole through welding, anchoring, bolts and pins.
There is also a small one that prefabricated L-shaped step members are built in the side wall according to the slope of the stairs to become cantilever stairs. This construction method for assembling small prefabricated members has strong adaptability, simple transportation and installation and low cost.
For some on-site pouring and some prefabricated assembly, stair beams are usually formed and poured first, then prefabricated steps and platform plates are installed, and then concrete is poured at the reserved steel bar joints of the three to form a whole.
This method saves the formwork and shortens the construction period compared with the whole on-site pouring, but it still maintains the characteristics of accurate processing of prefabricated components, and can adjust the size and form. Reinforced concrete stair tread requires the surface to be easy to walk, wear-resistant, non-slip and easy to clean.
Surface materials are generally plastered with cement mortar, which can be terrazzo surface, cylindrical brick and marble veneer, as well as linoleum, plastic paving materials and carpets. Near the tread, anti-slip strips such as cement emery, mosaic, plastic and rubber can be used, and ceramic or metal materials with grooves can also be covered on the tread, which also plays a protective role.
2. Steel stairs
Used in factories and warehouses, etc. In public buildings, it is often used as a fire escape staircase. The load-bearing members of steel stairs can be shaped steel, the nodes of each member are generally connected or welded by bolts, and the surfaces of the members are painted to prevent rust.
Pedals and platforms should be made of embossed or checkered steel plates to prevent slipping. In order to reduce noise and consider the decorative effect, the steel pedal can be paved with elastic surface layer or concrete, stone and other surface layers. You can also directly lay reinforced concrete or stone steps on the steel beam. This kind of stairs is called combination stairs.
3. Wooden stairs
Because it can't prevent fire, its application range is limited. There are two kinds of dark steps and bright steps. The steps embedded in the groove of the inclined beam of the stairs (also called stair side) are hidden steps; The triangular wood nailed to the inclined beam is open-frame. The surface of wooden stairs is protected against corrosion with paint.
Special stairs
According to the function, there are mainly three kinds of safety ladders, fire ladders and automatic ladders.
1, fire escape
Also known as evacuation stairs, it is used for emergency evacuation of people in residential buildings, public buildings and multi-storey factories. In addition to low-rise public buildings with high fire resistance rating and unit residential buildings with less than six floors, other buildings with more than five floors, such as medical, performance and sports buildings, and civil buildings such as dormitories and hotels, as well as multi-storey factories with more than 5-25 employees per floor/kloc-0 ~ 300 square meters.
In addition to the main stairs, emergency evacuation stairs should also be set up. For apartments or high-rise buildings with floors above 10, in order to prevent elevator shafts and stairwells from losing their vertical traffic capacity in case of building fire, smoke stairs should be fortified. The number and width of safety ladders are determined according to the needs of personnel evacuation, and the slope is not more than 45.
The door leading to the aisle of the safety ladder should be a fire door with a fire resistance limit greater than 1.5 hours, and automatic fire extinguishing equipment can be installed on it. The door at the exit of the fire escape should be opened outward, and should not hinder the traffic, and should be connected with outdoor venues or roads. If the evacuation stairs are set outdoors, the smoke will be discharged quickly and the evacuation effect will be better. Safety ladders are mostly cast-in-place reinforced concrete stairs or steel stairs.
2. Fire escape
Usually steel stairs, dedicated to firefighters. Its location and quantity are determined according to the nature of the building, the number of floors and the fire protection requirements. There are two kinds of fire ladders: straight-up type and inclined-up type: straight-up type is mostly reinforced ladder, which is only used in the first and second floors.
The inclination of the inclined type is 60 ~ 80, which requires handrails, railings and a cantilever rest platform. For the use needs and safety considerations of high-rise buildings, the platform shall be provided with a lifting port with columns on three sides not less than 600×700 mm, and the minimum elevation of the fire escape shall be 2 ~ 2.5 meters from the ground to prevent idle people from climbing.
3. Escalator
It consists of steel trusses, gears, pulleys, guide rails, movable connecting rods and so on, which span between floors. , equipped with pedals, driven by electricity. The gradient of escalator is about 30, the width can be divided into single use and double use, and the running speed should be about 0.5m/s ... The layout forms of escalator are parallel, cross and mixed.
Compared with elevators, escalators have the characteristics of higher passenger load rate and continuous flow of people, and are suitable for public places such as department stores, stations, subways, and floors where people are concentrated in high-rise buildings.
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