RĂSPUNSURI SUBIECTE CONSTRUCŢII DIN LEMN –limba engleza

1. The physical characteristics of wood are determined for the ideal wood with a

moisture content of 12% and they are:

- Density (ρ – kg/mc);

- Moisture content (%);

- Contraction and swelling ;

- Thermal proprierties (thermal conductivity, thermal dilatation, specific

heat);

- Behaviour to high temperatures

2. Wooden members subjected to uniaxial bending are calculated to:

- Design resistance in bending:

m,d = crit x fm,d

- Shearing cross the grains in supports or in critical sections where

concentrate forces are applied:

d

- Shearing in the neutral axis:

d

- Compression cross the grains in supports:

c,90,d kc,90 x fc,90,d

- Serviceability limit states verification, limiting the initial and final

deflections:

Uinst Uadmis

Ufin Uinst x (1+ kdef) Uadm

For biaxial bending the verification is :

or

3. Timber framings used for roofs depends on the construction transversal span.

They are:

- Timber framings with a single purlin (ridge purlin);

- Timber framings with one purlin on each slope;

- Timber framings with one purlin on slope and a ridge purlin;

- Timber framings with many purlins on each slope.

Timber framings members are:

- Posts (columns);

- Bearing elements for posts;

- Purlins longitudinaly disposed ;

- Rafters along the roof slope

- Roof boarding as support for roof covering;

- Transversal bracings;

- Longitudinal bracings.

4. Timber framings used for roofs for constructions with vertical longitudinal

structural elements depends on the transversal span of the

construction.

Timber framings members are:

- Posts (columns), vertical and inclined;

- Bearing elements for posts;

- Purlins (of ridge, intermediary) longitudinaly disposed and standing on

posts;

- Rafters along the roof slope

- Roof boarding as support for roof covering;

5. The floors with timber beams have the structure made from:

- Equidistant beams standing on vertical structural elements (walls, frames)

- Connections elements

The beams have 3-5 m spans and they are disposed to 70-120 cm between

them.

The beams may be disposed on one direction, or on one direction principal

beams, respectively secondary beams on the other direction.

The beams may be:

- Solid timber beams;

- Beams with solid timber flanges and a thick web;

- Beams with solid timber web and thick flanges;

- Trusses ;

- Glued laminated beams (with constant or variable section)

The connection elements may be:

- Disposed on the superior part of the beams

- Disposed on the superior part and inferior part of the beams

- Between beams