×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*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.

# What is the minimum foundation width to be used in the bearing capacity formula

## What is the minimum foundation width to be used in the bearing capacity formula

(OP)
Hello

i have a small square pad to carry high concentrated temporary loading on a road surface. i am just approaching this as a foundation problem . i was wondering if there is any minimum requirement for foundation width (B) when using the traditional bearing capacity formula, at least theoretically .

Much appreciated

### RE: What is the minimum foundation width to be used in the bearing capacity formula

I don’t think there is a theoretical limit, just as long as you satisfy BC and settlement. And include at least 100 mm of concrete between your column (?) and pad edge.

Give us some more detail, what’s the load and how is it transmitted to the pad?

### RE: What is the minimum foundation width to be used in the bearing capacity formula

(OP)
Thanx EireChch .
Temporary surface heavy wheel load (250 kn) over s small concrete or steel pad with 0.6 m width and length. Just wanted to make sure that bearing capacity of square footing is applicable to small footings but it seems to be no problem.

### RE: What is the minimum foundation width to be used in the bearing capacity formula

That sounds a bit like a plate load test size and force.

You don't want the area of the pad to be similar size to the soil particles resisting. But in your example it sounds like the particles below are confined by the existing road surface which will load spread. Punch failure might be a risk but I think the load is probably too low.

### RE: What is the minimum foundation width to be used in the bearing capacity formula

What does your Geotech report specify for minimum footing width and allowable bearing pressure?

Typically I see reports specify around 3' minimum width for a spread footing.

### RE: What is the minimum foundation width to be used in the bearing capacity formula

define, "Small" and define, "High" then we'll have something to discuss.

f-d

ípapß gordo ainÆt no madre flaca!

### RE: What is the minimum foundation width to be used in the bearing capacity formula

I believe they did. 250 kN wheel load over a small (0.6m x 0.6m) concrete or pad.

The bearing capacity formula should work for a footing of that size. That is a large load so I would expect to see some settlement and cracking in the road if you don't fail the soil.

### RE: What is the minimum foundation width to be used in the bearing capacity formula

Maybe try a small test by jacking up heavy vehicle on a plate check for damage as you increase the load.

### RE: What is the minimum foundation width to be used in the bearing capacity formula

Anything under a 3' footing, I reduce the bearing capacity by the ratio B/3. Im not sure if this is written in any code, or if its just a rule of thumb my superiors use.

-MMARLOW EIT

### RE: What is the minimum foundation width to be used in the bearing capacity formula

I think that the IBC indicates that the minimum width for foundations is 300 mm.

But based on the size of your pad (0.6m x 0.6m), I think that a plate bearing test will give you very useful information.

Anyway, based on your load and pad size, you are putting about 700 KPa of bearing pressure. Not sure if your soils can give you that presure with an adequate FOS. Perhaps you will need to replace at least 1.2 m of soil with good engineering granular fill to get the bearing capacity that you need.

### RE: What is the minimum foundation width to be used in the bearing capacity formula

#### 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.

#### Resources

White Paper - How ESI is Helping Move New Medical Device Product to Market Quicker & More Cost Effic
Early Supplier Involvement has long been a strategy employed by manufacturers to produce innovative products. Now, it almost seems like a necessity. Because decisions made in the design phase can positively affect product quality and costs, this can help add value to OEM bottom lines. This white paper will discuss many facets of ESI, including why itâ€™s so valuable today, what challenges limit the benefits of ESI, how cost is impacted, and more. Download Now
White Paper - Moving to a Driverless Future
This white paper describes what we see as the best practices to support a sustainable engineering process for autonomous vehicle design. It exposes how to use simulation and testing in common frameworks to enable design exploration, verification and validation for the development of autonomous cars at a system, software and full-vehicle level to drive a mature product development process for automated driving. Download Now
Research Report - How Engineers are Using Remote Access
Remote access enables engineers to work from anywhere provided they have an internet connection. We surveyed our audience of engineers, designers and product managers to learn how they use remote access within their organizations. We wanted to know which industries have adopted remote access, which software they are using, and what features matter most. 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:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!