×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

How effective is soil damping in pile response to seismic event
3

How effective is soil damping in pile response to seismic event

How effective is soil damping in pile response to seismic event

(OP)
This is an extension of my thread posted in Foundation Engineering forum. I would like to post it here, in case no one extends my previous discussion.

4July greeting to all our pals in States

In modelling superstructure with pile included where deemed necessary, pile flexibility is taken advantage of in attempt to cut down seismic energy absorption. There have been suggestions to employ spring elements in pile modelling.

My opinion is that large damping is built in even poor(mud) soils, and large energy absorption is already built in.

As far as piles are concerned little vibration exists, and should behave almost rigidly. And the superstructure should vibrate as if the base is fixed.

I am talking about an extreme condition to stimulate the discussion

Anyone interested please join in.

regards
IJR

RE: How effective is soil damping in pile response to seismic event

In most cases, the soil-pile interaction is considered on the basis of determining what larger displacement repsonses can be expected for the structure as a whole.  This response can't be predicted using the fixed foundation scenario.  Fixed foundations will give maximum moment and shear response but are often considered too conservative.

You're assumption that the soil will asorb energy is correct, but by absorbing energy the soil has to yield and this is what leads to displacements.  The other important item is for soils that will liquify.

RE: How effective is soil damping in pile response to seismic event

(OP)
Thanks Qshake

Your comments brought in some light as usual. But if you visit here again please comment on the role of soil damping in cutting down the displacements.

Respects
IJR

RE: How effective is soil damping in pile response to seismic event

Hello IJR.

I am not sure if it can be of any help, but French regulations (Fascicule No 62 - Titre V) for example multiply the spring constant simulating elastic soil behavior, based on pressuremeter measurements, by a factor of 2 when dealing with seismic loads. I think this will lead to smaller displacements induced in the superstructure.
As Greek regulations provide with design values for seismic acceleration at the soil surface, there is propably another effect that interferes based on the assumed distribution of seismic acceleration with depth, but I think this depends on the model assumed. In that case in order to consider dumping one should use the real or design accelerograph curve as forced vibration.

If my comment is very well known or of doubtful value please consider it with caution as I am not an expert.

Regards

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

White Paper - Strategies to Secure Connected Cars with Firewalls
White-hat hackers have demonstrated gaining remote access to dashboard functions and transmissions of connected vehicles. That makes a firewall a vital component of a multilayered approach to vehicle security as well as overall vehicle safety and reliability. Learn strategies to secure with firewalls. Download Now
White Paper - Model Based Engineering for Wire Harness Manufacturing
As complexity rises, current harness manufacturing methods are struggling to keep pace due to manual data exchanges and the inability to capture tribal knowledge. A model-based wire harness manufacturing engineering flow automates data exchange and captures tribal knowledge through design rules to help harness manufacturers improve harness quality and boost efficiency. Download Now
White Paper - What is Generative Design and Why Do You Need It?
Engineers are being asked to produce more sophisticated designs under a perfect storm of complexity, cost, and change management pressures. Generative design empowers automotive design teams to navigate this storm by employing automation, data re-use and synchronization, and framing design in the context of a full vehicle platform. Download Now
eBook - Simulation-Driven Design with SOLIDWORKS
Simulation-driven design can reduce the time and cost of product development. In this engineering.com eBook, we’ll explore how SOLIDWORKS users can access simulation-driven design through the SOLIDWORKS Simulation suite of analysis tools. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close