US: Tel: 1-206-279-3300
EU: Tel: +30 6986 007 252
Google+ Facebook Twitter LinkedIn
  • FREE VERSION OF RCsolver - Concrete Design with EC2, EC8, and ACI 318

    Get full capabiltiies with our free version of RC-Solver once you signup for our newsletter. With the free version you will have to wait 30 seconds for advertisements.

    Get the free version now Advertise with RCsolver

    Upgrade to the ad free version for only $150

    * Direct download link is available in the second e-mail that you receive, since you verify your subscription.

Structural regularity according to Eurocode 8

Structures with irregularities in plan or in elevation present special ductility demands in certain locations contrary to the general demand of uniform ductility distribution in normal buildings.

Criteria for regularity

A. Criteria for regularity in elevation

EC8(§ considers as regular in elevation the buildings that satisfy all the following conditions:

The irregularity in elevation is expected to have more severe effects in the design and in the seismic response of the building rather than the irregularity in plan. So:

In buildings irregular in elevation, the behavior factor q is reduced 20% ο in comparison with buildings that are regular in elevation.

Figure 1: Criteria of regularity in elevation for buildings with setbacks (EC8 §

B. Criteria of regularity in plan

EC8(§ considers as regular in plan the buildings that satisfy all the following conditions:

0.3rx ≥ ex and 0.3ry ≥ ey

rx ≥ ls and ry ≥ ls

where the radius of gyration of one floor in the two directions can be calculated from the polar moment of inertia of the floor mass in plan as:

Figure 1.2: Design response spectrum according to EC8 (Spectrum Type 1, soft soils Type C, Elghazouli, 2009).


Please sign up to download the free version of RCsolver and use all the capabilities of our software for free!

The free version of RCsolver contains advertisements. It is a full version, containing all features.

Easily upgrade to the full version without advertisements only for 150 USD!

Download RCsolver and join the world of Concrete Design according to Eurocodes 2 and 8 and ACI 318-11 with an impressive and modern software!

RCsolver: Learn more

Advertise with RCsolver

Feel free to contact us at for more information, pricing options and special offers!

E-mail List Signup

Signup to our Email List for the latest information about our products, support and more.