Zveza društev gradbenih inženirjev in tehnikov slovenije
ovitek_maj_2009.jpg

Objavljeno v: Gradbeni vestnik - 6, 7 - 1965

Avtorji

prof. Svetko Lapajne, inž.

Nekaj prijemov iz prakse statika-konstruktorja

UDK: 69.00:624,04:624.9

Brezplačen elektronski izvod revije:
Celoten članek si preberite v elektronski različici revije Gradbeni vestnik v PDF obliki.

SOME FEATURES FROM PRACTICE OF AN ENGINEER-DESIGNER

SOME FEATURES FROM PRACTICE OF AN ENGINEER-DESIGNER
Synopsis
The author presents solutions for three little problems :
The first problem relates the calculus of the top and bottom stiffnesses of an element with irregular moment of inertia. The basis is the method of the
elastical center. Computing the Csonka’s stiffness —V
ds/j
and the sidesway-stiffness ~ir7~r all the other stiffnes-
z2 ds/j
ses and the carryoverfactor coefficients are easily obtainable.
The second problem deals with the size of the support moments of a square two-way slab, fully restraint and uniformely loaded, so that the Poisson’s ratio is taken into acount. The bending moments of
the other orthogonal direction cause a reduction of yielding on the observed direction. The deduction yields for the fixed-end moment the expression q L2 . 0,0323 and for the positive field moment q L2 . 0,0215.
The third problem is the control designing of compressed construction elements, loaded with an exceptionally strong wind blow (150% of the usual). For this case our code allows 150 °/o higher stresses. It is proved, that there is n’t question for all purely bended sections, nor for concrete tresses in columns. Meanwhile in stanchions the amount of steel reinforcement increases. For this case a formula is given, using the normal allowable stresses and the normal windmoments in combination with only 2/3 amount of the normal axial compression and only 2/3 of the bending moment acused by the vertical loading.
gospodarsko-prauna vprašanja

The author presents solutions for three little problems :

The first problem relates the calculus of the top and bottom stiffnesses of an element with irregular moment of inertia. The basis is the method of the

elastical center. Computing the Csonka’s stiffness - 1/ds/j and the sidesway-stiffness  all the other stiffness 1/z2 ds/j

ses and the carryoverfactor coefficients are easily obtainable.

The second problem deals with the size of the support moments of a square two-way slab, fully restraint and uniformely loaded, so that the Poisson’s ratio is taken into acount. The bending moments of

the other orthogonal direction cause a reduction of yielding on the observed direction. The deduction yields for the fixed-end moment the expression q L2 . 0,0323 and for the positive field moment q L2 . 0,0215.

The third problem is the control designing of compressed construction elements, loaded with an exceptionally strong wind blow (150% of the usual). For this case our code allows 150 °/o higher stresses. It is proved, that there is n’t question for all purely bended sections, nor for concrete tresses in columns. Meanwhile in stanchions the amount of steel reinforcement increases. For this case a formula is given, using the normal allowable stresses and the normal windmoments in combination with only 2/3 amount of the normal axial compression and only 2/3 of the bending moment acused by the vertical loading.

Karlovška 3
1000 Ljubljana, SLOVENIJA

Phone: +386 1 52-40-200
Fax: +386 1 52-40-199
email: gradb.zveza@siol.net,
gradbeni.vestnik@siol.net
http://www.zveza-dgits.si