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# Seism

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# Seism

Calculation of seismic movement effects is dependent on a number of parameters, that in turn are dictated or recommended by various legislative norms. This program, with Italy as country of origin includes norms native to that country as well as the Europe wide Eurocodes 8.
This latter is the more relevant for users outside Italy and will be treated here. If it is desired to consult the Italian standards, the user is referred to the Italian language help file, accessible directly by executing the file: Muri_IT.chm in the home folder for the program.

The following parameters can/should be entered or considered by the user.

Soil Category

 Type A soils Stone like formations or very rigid homogeneous soils S=1 Type B soils Deposits of highly condensed sands or gravels or highly consistent clays S=1.25 Type C soils Deposits of moderately condensed sands or gravels or medium consistent clays S=1.25 Type D soils Deposits of granular, loose or slightly dense soils, or else cohesive soils of slight to medium consistency S=1.35

Project seismic acceleration

No seism Zone

Zone 1 = 0.35g

Zone 2 = 0.25g

Zone 3 = 0.15g

Zone 4 = 0.05g

Factor r

The recommendation for reinforced concrete walls factor r is a value of 1. Only for gravity walls or such as are deformable can this set to 2.
The factor is used in the determination of horizontal seismic coefficient.

Horizontal seismic coefficient Kh

See Theoretical notes. Used in evaluating project force in seismic condition.

Vertical seismic coefficient  Kv

See Theoretical notes. Used in evaluating project force in seismic condition with sign + or – depending on a more unfavourable effect.

The values of the horizontal and vertical seismic coefficients can be manually assigned by the user. They can also be calculated automatically by the software on the base of the maximum acceleration at site.

For the application of Eurocode 8 (geotechnical planning), the horizontal seismic coefficient is defined as follows:

where:

agR: reference peak acceleration on hard outcropping ground,

γI: importance factor,

S: soil factor, depending on the kind of ground (from A to E).

is the “design ground acceleration on type A ground”.