Code-checking of members with partially loaded areas

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Precast and bridge structural engineers often need to design and code-check partially loaded areas where they have to deal with reactions in bearings or concentrated prestressing forces from the tendons in the beams.

Partially loaded areas can be found on every structure. Some typical examples are bridge diaphragms with an area above the bearings, areas under the anchor, or concentrated load on the edge of a wall. Partially loaded areas are designed according to the requirements of the Eurocode and simultaneously are restrained by model geometry (openings, thickness, edges, abrupt change of cross-section).

Fig. 34	Partially loaded areas according to EN 1992-1-1.

We have heard many requests from structural engineers for solving this type of issue. With the new version IDEA StatiCa 20, we came with a solution on how to deal with triaxial stress in partially loaded areas. In these areas crushing of concrete is allowed, and the resistance of concrete in compression can be raised due to transverse confinement according to valid standards (Eurocode). The increase of the resistance can be up to 3 times the cylinder strength of concrete.

Solution with IDEA StatiCa

With IDEA StatiCa, you can design and assess reinforced concrete structures while taking into account the influence of the increasing compressive resistance of concrete in partially loaded areas. Horizontal reinforcement bars are automatically added to resist the transverse tensile forces and pass the Eurocode provisions.

This functionality guarantees that models are getting converge and simultaneously comply with design criteria for valid standards (Eurocode). The implemented method is independent of the finite element mesh. The bearing capacity is increased with the changing of the concrete area. The consequence of this state is constant stress along with the height of a cone. Dispersed fictitious struts affect the stiffness of the cone and correctly redistribute the transverse stress, which appears in this area. The density of each dispersed strut is increased to the direction of the applied load.

Using IDEA StatiCa for partially loaded areas brings less-conservative design, saving both material and money.


Please keep in mind some known limitations that come out from the standards valid in Eurocode.

  • Cones cannot coincide
  • The area Ac1 and Ac0 lie on the resultant of the acting force

 It should be remembered that this is a design model that cannot precisely describe the stress state over a partially loaded area whose actual flow is much more complicated. However, this solution allows the correct distribution of load to the whole model while respecting the increased load capacity of the partially loaded area. In addition, it correctly introduces transverse stresses in this area.

If you want to know more about the theory behind this new feature, you can find more information in our Theoretical background.

Partially loaded areas feature is available for the Enhanced version of IDEA StatiCa Concrete and Prestressing.

More about IDEA StatiCa version 20 

The new version of IDEA StatiCa is the biggest implementation of customer feedback and wishes we have had in years. 

Except for the new online licensing system, version 20 brought some more improvements for concrete design. Besides the partially loaded areas, you can enjoy our new parametric diaphragm templates, and if you are designing for the British construction market, you would for sure welcome the implementation of UK National Annex.

If you are more into the steel connection design, the highlights of the version are section model view, 110 new connection templates added to the starting wizard, brand new steel-to-timber connections, or usability improvements thanks to the cross-section library favorites

Would you like to see more of the new features? Read full release notes for Concrete or even better – watch the recording of version 20 introduction webinar:

Do you like our new features? Put IDEA StatiCa to the test and start your 14-day FREE trial!