Tragwerksplanung mit 3D-Gesamtmodellen in der Praxis

Abstract

Structural engineering with holistic 3D models in practise

This article outlines the findings of a systematic survey of structural engineering offices regarding their current practices in structural analysis and design for building construction. As well as assessing the current situation regarding the use of holistic 3D models in everyday planning, it examines the potential for optimisation in terms of using concrete and reinforcement more efficiently. Different modelling methods are applied depending on the planning phase, with holistic 3D models being widely used. The standard procedure involves linear elastic determination of forces for individual load cases on the embedded holistic 3D model, superimposing them to calculate the design forces and performing a nonlinear cross-section design. However, in this process, redistribution effects due to crack formation in the SLS as well as plastic behaviour in the ULS are neglected, and soil-structure interaction is not accounted for in the partial safety factor for additional restraint forces due to settlement, as specified in EN 1990. Material savings could be achieved through mechanically consistent calculation approaches in holistic 3D models. In fact, comparative calculations show that realistic modelling and well-founded design assumptions could result in material savings of around 30% in the foundation slab. However, implementing and accepting such methods in practice requires clear instructions, which are developing as part of an FFG research project in cooperation with planning offices, the construction industry, and software developers.