Frame Corners – A Common D-Region Problem

Traditional methods for designing reinforcement in frame corners are based on a set of detailing rules and equivalent strut-and-tie models. For various geometries and loading conditions, numerous strut-and-tie models are available in the literature. Selecting the appropriate model therefore relies heavily on the engineer’s experience.
A detailed verification of a strut-and-tie model—including anchorage checks and consideration of transverse tensile stresses in compressed struts—is time-consuming and labor-intensive.

The objective of this webinar is to present, using a specific example of a frame corner in the lining of a backfilled tunnel, a design approach based on the CSFM (Compatible Stress Field Method) implemented in IDEA StatiCa Detail.
This materially nonlinear method fully replaces the strut-and-tie model and, in addition to ultimate limit state verification, also provides assessment of the serviceability limit state (stress limitations and crack width).

During the webinar, the frame corner will be modeled as a cut-out segment of the structure. The correct support conditions and loading of this segment model will be explained. The outputs of the CSFM analysis and their interpretation will be discussed in detail.
Finally, a detailed demonstration will show how to use the software to design reinforcement for transverse tensile stresses in the “main diagonal” of the frame corner and how to optimize the reinforcement layout.

Want to see more webinars?

Learn more about discontinuity details design in reinforced and prestressed concrete with IDEA StatiCa:

• Master Your Design - Precast and Infrastructure Beams
• Master Your Design - Pier Caps
• Master Your Design - Prestressed Beam with Openings

Register for free and join the live webinar on Wednesday, February 25, 2026, at 11:00 CET (Prague time, UTC+1).