Half-floor staircase of a private house: Design and calculation

The device of any design of the structure, including the stairs, starting with the settlement. Better to spend time on paperwork than then spend money on fixing bugs and defects in the already finished construction. Properly done the calculations not only save budget allocated for the construction, but also to accelerate the execution of works.

Calculation of the stairs consists of the following steps:

• Preparation of input data for the calculation of T ladder - shaped with an intermediate platform, based on the aperture size 300h150 centimeters
• Determination of the number of steps of the staircase
• Determination of the height of the pad width and the intermediate
• Determination steps width
• Intermediate results of the calculation of T - shaped with an intermediate platform, based on the aperture size 300h150 cm
• Determining the size of the opening of the ladder

T- shaped staircase with a staging area for the opening 300h150 see: Start calculation

As I mentioned in the first part of the article "Design and calculation of interfloor staircase of a private house. T- shaped staircase with a staging area "calculation ladders must be made prior to construction of the building. To calculate the required data defined by the regulations, to help verify the correctness of its implementation.

Calculation of the stairs hold, given the space constraints for its installation. For example, because bearing walls lengths and widths home is not possible to make interstorey opening 300 centimeters in length and 150 centimeters in width. Length premises 450 centimeters (with an aperture through the wall), the width of 340 cm (the wall perpendicular to the aperture).

Note:

The calculation of the opening interstorey omitted, but, at the end of the material to be examined and a method for determining interstorey aperture sizes.

At first glance it may seem that the length of the opening 300 centimeters is sufficient for a safe and comfortable device ladder. So whether it is to be verified with the help of following is a calculation, which will help to find out what exactly happens staircase.

Determination of the number of steps in the staircase

To determine the number of steps, we use the following auxiliary table, which shows the height of the steps depending on the number and height of the floor:

Table 1. The ratio of height floor to the number of steps of the stairs.

The height of the floor of the building is 295 centimeters in view of the overlap (in Table 1 are guided to 3000 mm), according to table, the optimum number of stages will 15-16 units for such ladders., at the height of lifting stages 18-20 centimeters. At the same time, it should be noted that it is necessary to choose a number of steps that would still provide step width (width of the tread), handy when moving the stairs, it is this amount will be optimal.

Last (fascia) stage the upper deck will be located at the level of the finished floor of the second storey. Therefore, determining the number of steps necessary to consider a thickness and material which will go to their construction - in this case equal to four centimeters. To find out the height of the lifting stages carry out the following calculations:

(295 - 4 (ceiling height - material thickness)) / 15 = 19.4 centimeters steps

Taking the optimal number of steps - 15 pieces, in the further calculations need to make sure that the choice is really optimal.

Fig. 1. The inclination angle odnomarshevoy ladder.

Figure 1 shows a diagram for calculating the number of stages for the room 450 centimeters wide with an aperture of 300 centimeters. From the diagram clearly shows that the length of the opening is not sufficient for the device odnomarshevoy ladders, because of the fact that the angle of inclination exceeds 50 °! For this reason, and applied the L-shaped staircase with intermediate platform, which allows to change the angle of rotation, if place it on the perpendicular wall, and lifted up to a certain height pad, and change the angle of inclination of the stairs.

How is the calculation

For the calculation of the need to take a sheet of paper of A4 standard format and make room scheme, located in the same plane as the two walls, as shown in Figure 3 (see. below). As in Figure 1 the height of the steps is applied diagram is then necessary to determine the width of the site, which It is both the width and height of the stairs, on which it will be located, given all the other options premises.

Attention - it is important! All sizes recommended schematic drawn to scale, it will clearly see and evaluate the result. It is very convenient to carry out this kind of drawings to use special paper with drawn on it millimeter mesh.

Determination of the height of the pad width and the intermediate

Continuing the calculation necessary to determine the width of the intermediate area, which is also the width of the stairs. It is necessary to take into account the fact that the installation space is limited in size ladder that can lead to the fact that the staircase has recommended for private homes width of 90-120 centimeters, is inapplicable. For what reason?

Fig. 2. Effect of ladder width at its angle of inclination.

Apart from the fact that there is a height restriction of the site from the floor position, the angle of the stairs is the steeper, the wider the intermediate platform and ladder, respectively. It is necessary to solve two problems - firstly: the angle of inclination should not exceed 42 °; secondly pad width should be no less than 80 centimeters.

Figure 2 shows a diagram of changes in inclination depending on the width and height of the ladder layout level 95-100 centimeters grounds from which it is seen that the width of the stairs and landings should not exceed 80 centimeters.

It is now known, the effect of the intermediate platform and stairs in width angle. Next you need to determine how high you can raise the intermediate pad. The recommended value lumen critical point between the lifting stage and the overlap is 200 centimeters.

To calculate the following formula is used:

200 cm (clearance size) / 19.4 cm (step height) = 10.3 degrees (rounded to 10).

From this result we can conclude that the stairwell length of 300 centimeters enters upper stairway of 10 steps with an intermediate platform 80 centimeters wide. The remaining five stages will be placed in the lower flight of stairs respectively playground will be located at the level of the fifth stage of the first flight of stairs.

For further calculation formula is used to determine the height of the level of the site:

(295 cm (height of the room with the ceiling) - 4 cm (the thickness of the stages of the material) - 10 steps x 19,4 cm (height levels rise)) = 97 cm (with the thickness of the material of steps - 101 cm).

Fig. 3. To locate the height and width of the intermediate area.

Transferring calculation scheme

All payments received are applied to the circuit premises, as is done in Figure 3. As mentioned above, to chart it will be convenient to use a paper with millimeter grid that facilitate tracing it in a certain scale, eg 1:10. The walls A and B in the diagram are arranged in one plane. On the walls marked Width equal to 80 centimeters. Between the ladder and the surface of the walls is necessary to leave a gap 5 centimeters. From the ground level is measured four centimeters (thickness stages of the material) and is held horizontal line (X).

Further, from the line (X) is measured distance of 19.4 centimeters and is held next horizontal line, and so applied marking with a gap of 19.4 cm to the floor surface. All stages separated by horizontal lines as shown in Figure 3.

Then, from the top point of the fascia must count 10 steps which the wall A enter the stairwell. When all the horizontal lines are drawn, you can move to a certain point of criticality lift: the wall B is measured by the distance from the intersection interstorey overlap with the beginning of the opening of the ladder to pass a critical point (Y) (Figure 3, right), where the opening width is 150 centimeters. It is clearly seen that given a thickness of 4 centimeters material (red circle) from the third stage at the level of criticality lifting distance is obtained 207.7 centimeters. This figure is more than the recommended 200 cm, therefore, the whole calculation and selection of the height of the site location completed without error.

Determination steps width

Now that you have a reference point to set the maximum height of the staging area, you must proceed with the design ladder by drawing it on the circuit. The next task is to define the width of the steps.

Fig. 4. calculation scheme tread

The opening included ten steps and intermediate pad width of 80 centimeters. Step width determined by the formula:

215 cm (distance from m. A to pad) / 10 degrees = 21.5 cm (step width)

From point A to the right (arrow) you must measure 21.5 cm and draw a vertical line marking. The value obtained gives the width of the stage and, in the same way it is necessary to measure out and spend the rest of the vertical lines, as shown in Figure 4.

From the point of intersection of grid lines the width and height of the steps necessary to carry out the landing diagonal line, indicating the tilt axis stairs obtained inclination angle should be about 42 °. If all sizes are made in a certain scale, the angle of inclination can be checked by measuring its protractor. Blue highlighted line tilt.

Further, highlight red ladder and connect the L-shaped line marking line width and height of step (diagonally divided square). Figure 4 shows what happened 15 steps and intermediate space. Upper march comprises 10 stages, the lower March - 5 degrees.

The result was a step width which is equal to 21.5 centimeters, which is insufficient for safe and easy movement of the stairs. Arranging step to ensure the safety of movement, using the simple formula: Width + Height level = 45 cm ± 2 cm (43... 47 cm) obtained by the calculation: 21.5 cm (step width) + 19.6 cm (step height) = 41.1 cm.

Overhang method steps

For this case easiest to use this method of increasing the tread width as the overhang stages, one above the other, by an amount of 1-5 cm. This embodiment is generally used in cases where the other way to increase the width of the steps is not obtained.

To determine the optimum level for the width of the case, it is necessary to determine the magnitude of the inlet stage step. To do this simple calculation is performed using the formula:

45 cm - 19,6 cm (step height) = 25.4 cm (in round figures - 25.5 cm) - this will be the width of the stage, with an overlap, wherein the amount of puffing:

25.5 cm - 21.5 cm = centimeter 4

Consequently, steps for the device need not material width of 21.5 centimeters, and more - 25.5 centimeters. Final calculation of the formula that determines the safety parameters steps of the staircase, gives:

25.5 cm + 19.6 cm = 45.1 cm - value corresponding index formulas for calculating the proportional stages settings optimized for the safe movement of the ladder. Thereafter, it is necessary to reflect increasing steps in Scheme width, and at the same time, draw the material thickness of stages equal to four centimeters.

Fig. 5. Diagram showing increasing degrees of width

Horizontal marking steps thickness from the upper fascia stage, taking into account the thickness of four centimeters of the material is applied to the circuit as shown in Fig. Then the applied vertical markings showing additional steps width also equal to four centimeters, it begins by applying the same upper stage fascia. Yellow color in Figure 5, is highlighted step width, 21.5 cm, obtained by calculation, red denotes extra width of 4 cm. Ultimately, the obtained level 4 cm thick and 25.5 cm wide.

Recommended ratio between the width and height of the steps

You must now turn to the table containing the recommended ratio of the width and height of the steps:

Table 2. The ratio steps of the staircase dimensions.

In Table 2 are marked in green aspect ratio, suitable for comfortable movement. Convenient dimensions for movement ratio highlighted in yellow, and relatively easy - blue. stages Size 25.5 cm x 19.6 cm, the resulting above-stated calculations, complies with regulatory requirements, but, since the step width is obtained by their increase due to the overhang with the launch of four centimeters of each other, it makes a convenient ladder only to climb, to descend it is relatively comfortable.

Subtotal ladder calculation T- shaped with an intermediate platform for opening dimensions 300h150 cm

Subtotal

Summarizing the interim results obtained by calculating the results we can say that the ladder sizes obtained in the course of designing, match regulatory requirements, but the staircase, however, obtained only relatively easy, due to the fact that there was a size limit interstorey opening:

Fig. 6. Example lifting and descending the stairs designed

Obtained by the maximum angle of inclination of the ladder, equal 42 °.

Step width due to the lapping quantity makes four centimeters stage ladder relatively comfortable for the descent. This is due to the fact that during the descent due to the overhang on four centimeters above the stage level, their work width will not be 25.5 cm and 22.5 cm (Figure 6), i.e., loses at least 3 cm working width steps.

Fig. 7. Overall ladder diagram T- shaped intermediate platform.

In general, the drawing projection ladder T- shaped intermediate platform summarized calculations carried out previously. Drawing allows you to look at the results of calculations in a bulk format and obtain a clear idea of ​​the results of the work performed.

Fig. 8. Ladder T- shaped with an intermediate platform. Side view.

Fig. 9. Ladder T- shaped with an intermediate platform. View from above.

Figures 8 and 9 show the results of calculations in a volume format. It is seen that yet balusters, handrails, fences and other things. All of this has yet to count and, in addition, to develop a design solution stairs - what do stringers, choose the material for the manufacture of steps and many others. Thus, completed only about half of the way, but even now you can see the stairs, of which the development of the project discussed in this and previous articles.

Now you can spend the analysis of the results and find out why the stair turned conditionally comfortable. The answer lies in the size of the opening interstorey limited length of 300 centimeters. Under existing rules ladder calculation begin with, find out the length of the opening necessary for her or, more simply, the aperture is adjusted for the stairs instead of a ladder under it.

We return back to the already designed the stairs and try to calculate it again:

The calculation was based on the limited size of interstorey of the opening that led to the need for the device 15 degrees height of 19.4 centimeters. In this arrangement the ladder to reduce the lift height will not work. Now we need to calculate how the device should be comfortable stairs, if we ignore the restrictions.

Determination of the required parameters stairwells

To do this, go back to Table 2 of this article and take the other two steps of the indicator parameters for calculating the length of the opening - the ones where the ladder It is comfortable both for lifting and lowering the parameters for steps, for example: 19h26 centimeters (15 steps) or 17h28 centimeters (17 steps).

The calculation is performed by a simple formula:

step width = X number of stages of the opening length.

Substituting numerical values, we obtain the following values ​​for the length of the opening:

26 x 15 cm = 390 cm or 28 cm x 17 cm = 476

From the values ​​obtained it is seen that the best option would be a device 15 degrees, and the width of the opening device for easy ladder this case is 390 cm. Hence the conclusion, confirming what was said earlier - first designed staircase, and only then opening the parameters are calculated, but not vice versa. Of course, this classic method is applicable only in the case where a perfect available in which area and layout of the house and let you do the calculations in this order, and not, as in the case considered above a size limit stair opening.

The limited size of the opening

In the case of the restriction opening size also can be made more convenient ladder T- shaped intermediate platform. To do this, you need to change the way in which the ladder is attached to the inner lining opening. Earlier designs discussed embodiment, wherein the upper fascia step is flush with the level of the finished floor of the second floor, in a new embodiment can reduce required number of steps, if omitted below the floor level of the upper fascia of the second floor and instead mechanical fastening staircases to the aperture to apply interfloor Ceiling. It should be noted that such a change in the way a ladder fixing to floor slabs will cause the need for repetition of all calculations.

With this embodiment, which will hereinafter be called the second embodiment of the ladder unit may have install risers, with almost the entire stairway will closed, it can also give certain advantages. That calculation is carried out as a staircase T- shaped with an intermediate platform with the previously preset parameters ladder and aperture facilities of the second embodiment will be discussed in the following article.

After construction of the second embodiment ladder calculations T- shaped intermediate area, in the next article will be discussed on the further device stairs - balusters, handrails and other comparatively small but important details. Work on the settlement is not over yet, but we must think about and its final completion - development of the original design solutions ladder, which will make it something more than just a functional design that provides access to the second floor building.