Vertical walled section

the part of a silo or a tank with vertical walls

Silos Tank
Figure 1.1 — Flow patterns

1.5 Notations

1) For the purpose of this prestandard, the following symbols apply.

NOTE The notation used is based on ISO 3839:1987.

2) A basic list of notations is provided in ENV 1991-1, "Basis of design" and the additional notations below are specific to this Part.

Latin upper case letters

A cross-sectional area of vertical walled section

C wall load magnifier

C0 maximum wall load magnifier

Cb bottom load magnifier

Ch horizontal load magnifier

Cw wall frictional traction magnifier

Cz Janssen coefficient

Fp total horizontal force due to patch load on thin walled circular silo

Ks design value of horizontal/vertical pressure ratio

Ks m mean value of horizonal/vertical pressure ratio

Pw resulting vertical load per unit perimeter of the vertical walled section

U internal perimeter of the vertical walled section Latin lower case letters dc characteristic cross-section dimension (Figure 1.2)

e the larger of e^ and eo eY eccentricity due to filling (Figure 1.2)

eo eccentricity of the centre of the outlet (Figure 1.2)

h distance from outlet to equivalent surface (Figure 1.2)

h1,h2 parameters used in the determination of vertical pressures in squat silos lh hopper wall length (Figure 5.3)

p hydrostatic pressure ph horizontal pressure due to stored material phe horizontal pressure during discharge (Figure 1.2)

phe,s horizontal pressure during discharge calcuated using the simplified method phf horizontal pressure after filling phfs horizontal pressure after filling calculated using the simplied method pho horizontal pressure after filling at the base of the vertical walled section pn,pni pressure normal to inclined hopper wall, where i = 1, 2 and 3

pp patch pressure pp,sq patch pressure in sqat silos pps patch pressure (thin walled circular silos)

ps kick pressure pt hopper frictional traction (Figure 1.2)

pv vertical pressure due to stored material (Figure 1.2)

pve vertical pressure during discharge pv vertical pressure components used to determine the vertical pressure in squat silos, i = 1, 2, 3

pvf vertical pressure after filling pvf,sq vertical pressure after filling in squat silos pv0 vertical pressure after filling at the base of the vertical walled section pw wall frictional pressure on the vertical section (Figure 1.2)

pwe wall frictional pressure during discharge pwe s wall frictional pressure during discharge calculated using the simplified method pwf wall frictional pressure after filling pwf,s wall frictional pressure after filling calculated using the simplified method s dimensions of the zone affected by the patch load (s = 0,2dc)

t wall thickness (Figure 1.2)

w width of a rectangular silo x parameter used to calculate hopper loads z depth below the equivalent surface at maximum filling z0 parameter used to calculate loads Greek lower case a mean angle of inclination of hopper wall measured from the horizontal (Figure 1.2)

b patch load magnifier g bulk weight density of liquid or stored material gi bulk weight density of fluidised stored material

6 circumferential angular coordinate

^ design value of coefficient of wall friction for pressure calculation mean value of coefficient of wall friction for pressure calculation

: effective angle of internal friction

:w angle of hopper wall friction for flow evaluation

Actions Silo Walls
Figure 1.2 — Silo forms showing dimensions and pressure notation
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Responses

  • Rudy
    How to calculate the pressure on the outlet of silo?
    8 years ago

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