Civil Engineering/Periods in etabs


QUESTION: From your answer to one f the query post, you ave mentioned that periods of between 4-5s is ok. Anything more tha 5 will have to look deeper. How about a value less than 4, say 2-3s?


Please give me details of the question and my response. Give me more detail from your own problem please.


---------- FOLLOW-UP ----------

QUESTION: I was looking for an answer to intepret the result of my etabs  model. The output of the period in mode 1 and 2 is around 2.8s and 2.2s and mode 3 is 1.8s. My question is is this model stiff enough? I understand that period is inverse of frequency. If that is the case, the frequency will be very very low (the comfortable frequency I am looking for us 5hz and more).

Dear SN

To interpret the period or rigidity of the structure you have 2 ways : 1- control the first and second ( X and Y ) mode period with tips given by seismic codes.

2- control the lateral sway and drift of the each story under lateral loading using the provisions of your local code.


Civil Engineering

All Answers

Answers by Expert:

Ask Experts


Babak Esmailzadeh Hakimi


I can answer questions in Structural Engineering, Earthquake Engineering, Project Management and Project Control topics!


I am experienced in the area of earthquake engineering in electrical power industry, i.e. Lifeline Earthquake Engineering. My focus has been on structural seismic design of power installations. Recently I have got involved in project management in the category of constructional engineering.

Sinam Consulting Engineers Co.

Bs degree in Civil Engineering from Ferdowsi University ,1988, Mashhad Iran, Ms degree in Earthquake Engineering, Sharif University of Technology, 1993, Tehran, Iran

©2016 All rights reserved.