Wooden joist ceilings – the most economic option for the house. They are very easy in mounting and at production. In comparison with reinforced concrete and with steel girders at wooden low heat conductivity. But any beams should be calculated and established attentively.
It is required to you
- - ruler;
- - calculator;
- - plane.
Instruction
1. Calculate section flexural strength, considering ratio 5:7 that means – if you take beam of 7 measures in height, then it is necessary to take 5 measures in width. The beam with such ratio will be very strong both on torsion, and on bend. Know: if to take width it is more, than depth of beam, then the excessive deflection will appear. If to take on the contrary, then the bend will appear aside.
2. Consider admissible deflection of floor beam proceeding from such ratio – 1/200 or 1/300 from beam length. For example, if to take beam which length of 600 meters, then after calculations we will receive that the deflection makes 2 or 3 centimeters.
3. Plane undermine beam from outside which the beam addresses down, at size of admissible deflection. That is give it some kind of type of arch. So you will achieve that the ceiling will not fall "bubble" down, in the middle the beam will become thinner, and at the edges there will be everything still.
4. Establish beam – at once it is visible that it is curved by arch to top. It will so not be constant, from action of loadings the floor beam will become straight.
5. Consider the curb weight of beam, it gives loading too. For inserted floors choose beams with loading of weight of 190kg/sq.m, but no more than 220 kg/sq.m, loading operational (temporary) – 200 kg/sq.m. Stack floor beams on the section of flight which is shorter. The step of mounting is equal to step of installation of frame racks.