General definition of structures
A march is a continuous series of steps that are located between two sites or levels. The device of stair flights is oblique, straight and curved. If the stairs have several marches, then the first has the name of the starting line, and the last one is the day off. The line that is in the middle of the march is called the shoot line. This line can not be closer than 30 centimeters from the edge of useful width.
Based on this rule, we find that the march should be at least 60 centimeters wide. The width depends on the layout, the dimensions of the opening and the intensity of use of the structure. If the march is located in the center of the room with a slope of 40 degrees, then its width should be designed for two-way traffic, but there must be a railing on both sides.
Note! The leading edge of the tread is lower than the last, so that the accumulated moisture is easily removed from it.
The staircase is a horizontal section, which is located between two flights. The sites are polygonal, quadrangular or curvilinear horizontal projection. Their dimensions are projected in proportion to the human step. The length is usually the same as the width of the span, and the width is equal to the width of the march. Therefore, if the marches are perpendicular to each other, then the square is square, if the marches are parallel - then the area is semicircular or rectangular.
Why reinforce the structure?
There are many factors on the marches: gravity of own weight, pedestrians, portable heavy things. All these forces exert pressure on top of the structure. As a result, the upper part is compressed, and the lower one, on the contrary, is stretched. To strengthen the structure, reinforcement of stair flights is used. This is done in the lower part of the plate, since the upper and so well resists the loads.
Single-ladder ladders are reinforced only in the lower part, although some builders do projects where the steel mesh reinforces the upper part. This grid does not add any stiffness, but it gives protection with strong bumps from the top and chips. Two-ladder ladders have a more complex reinforcement scheme. This is due to the fact that the useful and its own weight make pressure, which tends to destroy the construction. Therefore, reinforcement occurs in both the upper and lower parts, moreover, the upper reinforcement gradually passes from the platform to the step.
Note! Stairs receive a huge load, so they must be firmly attached to the concrete wall.
Installation process
The installation of stair flights starts after completion of the masonry according to the level of design marks. The intermediate platform and the first span are installed along the way of the inner wall of the staircase, the second platform and the span are at the end of the masonry of the floor. Before the installation, all dimensions are checked. Then everything is done in the following sequence:
- The place for installation is marked;
- The place of support is smeared with a layer of mortar;
- The platform is installed.
The level is used to check the horizontality and boundaries of the supporting edge with the pads. The distance between the platforms is checked by a special wooden template. Also, the laying of spans is also being carried out on interstitial floors. After this, the installation of stair flights begins. It is supplied by a crane using a forklift. The march rests first on the lower platform, and then on the upper one. If there are small deviations after installation, they can be eliminated with a crowbar.
Note! If the construction is lowered first to the top platform, then it may fall or jam between the platforms.
