Calculation of wooden beams

At the stage of creating wooden floors, one difficulty arises - calculation. The calculation of wooden beams of floors is one of those works that if you really want to, you can do it yourself. Just for this reason, in today's article, everything is about how to make a wood flooring calculation with your own hands.

The calculation of wooden floors must be done taking into account that according to the standard, the span for wooden beams is veiled from 2.5 to 4 meters. It is best when the beams have a rectangular cross-section with a ratio of height to width of 1.4: 1. During installation, the beams are embedded in the walls of not less than 120 mm. At the same time, every 3rd beam is reinforced with an anchor embedded in the wall (they also connect all the neighboring beams on the inner walls).

When calculating the load on the wooden floor, two types of them are taken into account - temporary and permanent loads. Permanent loads include the weight of the beam itself, the weight of the final coating and floors. This value in relation to interfloor floors is covered on average from 190 to 220 kg / m². Temporary (operational) loads include everything that in some way moves (moves) along the overlap. For these purposes, often emit no more than 200 kg / m².

Laying beams should go through a short section of the span. At the same time, the recommended step of their installation is equal to the step of installation of the frame racks.

The section of the wooden beams of the ceiling, taking into account the span and the installation interval with a load of 400 kg / m² (it is recommended to use such a load value in the calculations). Table 1:

There is also a table for less significant loads. It is designed for floors without a layer of insulation, as well as for wooden structures that are practically not subjected to loads (as is the case in an attic).

The minimum cross-section of the wooden beams of the ceiling, taking into account the span and loads from 150 to 350 kg / m² (table 2):

In case the round logs are used instead of rectangular beams, the following table will help to calculate. The minimum diameter of round logs, taking into account the span under a load of 400 kg / m² (table 3):

Depending on the type of connection between the beams, the value of the span span of the floor beams can also vary (table 4):

Note: the use of the spans indicated in the 4th table is permissible only in cases where the value of the temporary uniformly distributed load on the floor does not exceed more than 2.4 kPa.

In addition to the above, the value of the maximum spans for beams can be changed if there is a plan to have a cement screed or beams with ceilings mounted to a wooden batten (table 5):

Notes to table 5:

• As well as in the 4th table, the spans are applicable only if the temporary uniformly distributed load on the floor does not exceed 2.4 kPa.
• The presence of cement screeds does not allow for the possibility of overlapping cross vertical links between beams.

To calculate the overlap of unexploited attics, there are also separate values ​​for the maximum span of the beams (Table 6):