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

Related Articles


Design Load & Service Load

Design Load & Service Load

Design Load & Service Load

What is the difference between design load and service load?  Please provide a definition.

Thank you!

RE: Design Load & Service Load

The two terms come from the design of reinforced concrete. The old way, Working Stress, (similar approach to ASD with steel). The service load is the best estimate of the actual load that a concrete member may be called on to support.

The current way, Ultimate Strength. The design load is the service load increased by specified load factors in order to provide a factor of safety.

Traditional Examples:
Service Load = Dead Load + Live Load
Design Load = 1.4 x Dead Load + 1.7 x Live Load

Reference: "Simplified Design of Reinforced Concrete - Fourth Edition", Harry Parker

RE: Design Load & Service Load

The design load of a structure is the probablistic loading of the structure that would put the structure into a failure mode.

The service load is the load a structure would see on a daily basis when used as designed.

Failure does not mean on the ground. Buildings may reach failure, but still stand to allow people to exit safely.

Service loads reflect the daily loading of a structure and are most directly related to the comfort of the user of the structure.

A building designed soley on the basis of Ultimate or Design loading may be acceptable from the standpoint that it will resist failure to an acceptable point, but would be an uninhabitable building. Service loading directs one to deflection criteria amoung other things. A springy floor may be fine in an overall sense for capacity, but if the users of the structure are uncomfortable with a boucing deflecting floor the structure has "failed" from a serviceability standpoint.

Maybe this post is helpful or perhaps an overstatement of the obvious.

I am not trying to define loadings per any particular code, just more broad definitions.

Hope it helps.


RE: Design Load & Service Load

ASCE 7 "Minimum Design Loads for Building and Other Structures". It shows that design loads may be unfactored or factored for ASD or LRFD. ASCE 7 do not mention service load.

ACI 318 specifies service load as load without factors.

So it depends on Code or book you are using.

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!


White Paper: Industrial Control Basics: Contactors
A contactor is an electrical device used for switching an electrical circuit on or off. Considered to be a special type of relay, contactors are used in applications with higher current carrying capacity, while relays are used for lower current applications. Download Now
Research Report: State of IoT Adoption in Product Development 2019
This research report, based on a survey of 234 product development professionals, examines the current state of Internet of Things (IoT) adoption by product design teams, its perceived importance, and what features and capabilities teams consider important when making decision about adding IoT functionality to their products. 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