Equivalent static load earthquake force analysis method, Civil Engineering

Equivalent static load method

After the earthquake in Messina-Reggio Italy 1908, a team composed of engineers were sent on duty to study deteriorated buildings and investigate the reason. Aforesaid team has concluded by inspecting overturned buildings that earthquake horizontal forces caused the reversal. The value of this force has been assumed to be 0.08333 times as much as the building weight. Afterwards this opinioin has been expressed in the following term;

V=CW

Where in this term; V : earthquake force, W : building weight, and C : earthquake coefficient. For earthquake coefficient which has been suggested lately equal to 0.0833, the value of 0.1 has considered and majority of countries have accepted above aspect and now the earthquake coefficient is in the range 0.1. On the one hand, advancement and development of structure dynamic science and on the other hand, information achieved from recorded earthquakes indicate that there are various factors which are effective in determining earthquake force. Some of these factors are dynamical characteristics of structure such as periodicity, depreciation, mode form and structure capacity to adopt plastic transformation. Other factors such as soil type and seismicity also have a role on earthquake effects. These factors gradually opened their places in regulations, but the old format was maintained and implicitly the effects of above-mentioned factors have included in determining earthquake factor and earthquake force distribution. Some of the factors have been considered explicitly (such as alternation effect which is applied in determining earthquake factor), but others have been regarded inexplicitly (like softness effect). Despite of the significant efforts that has occurred in this case in the past eighty years, aforesaid method which is  known as static method, is unable to specify and determine the actual earthquake force explicitly, and it is purely a tool that designer can provide specified value of lateral resistance in structure which is of course indirectly effective in structural stability against earthquake horizontal force.

Equivalent static method basis

Seismic loading has begun from a simple thought and the assumption is that supposes earthquake force is equal to a horizontal force. Static seismic loading has been exposed to various changes, but its basis has been kept and equivalent static method is still propounded as one of the main seismic loading method in most of regulations.

The main elements of equivalent static method are :

1-      Basic shear calculation

2-      Basic shear distribution along the structure

3-      Investigations (Torsion, Reversal, displacement, etc.)

Generally, to design structural seismic, basic shear force is calculated and then distributes along the structure.

Overview on equivalent load method of the equivalent static

Multiple faults can be made ??on the static equivalent load method which will be mentioned to some of them in this section. These faults are: approximation in the reflectance spectrum of base acceleration, rational basis lack for determining the behavior factor R, and weaknesses in the method of earthquake distribution on structure. In addition, it is unknown that how much designed structure is safe and stable based on the criteria and whether resistance is an appropriate and adequate criterion for seismic design of a structure or that is necessary for other factors effects such as ductility, deterioration, and cumulative damage to be used.

Posted Date: 8/8/2012 3:39:28 AM | Location : United States







Related Discussions:- Equivalent static load earthquake force analysis method, Assignment Help, Ask Question on Equivalent static load earthquake force analysis method, Get Answer, Expert's Help, Equivalent static load earthquake force analysis method Discussions

Write discussion on Equivalent static load earthquake force analysis method
Your posts are moderated
Related Questions
With the aid of Mohr's circle diagram describe what means by active and passive Rankine states is in a cohesionless soil with a horizontal surface. As obtain an expression for the

Determine the dimension of the vertical side walls for a rectangular open channel designed to convey 150 cfs of storm water runoff. The runoff is collected in the parking lots and

What is the minimum radius, R min , that can be used on a horizontal curve with a 70 mph design speed, a maximum superelevation, e max = 8%, and a side friction factor, f = 0.10?

Q. What is Rail Lubrication? Rail Lubrication is done on sharp curves where lateral wear is considerable. The function of Rail Lubrication is to lubricate or oil the running fa

Behaviour of struts in compression compared with the behaviour of struts in tension? Also do you know a credible source that I can reference?


Analyse the continuous beam using moment distribution. A continuous beam ABCDE fixed at A carry a load of 2KN one metre from A at AB 3m. BC 3m, carry a UDL of 3KN/m and hinge at


Enumerate the Variation in tendon stress In post-tensioned construction, several tendons are simultaneously stretched and anchored at the ends. It is assumed that all tendons