Project Details
Projekt
Wrapped Hybrid Tubes
Applicant
Professor Dr.-Ing. Ludger Lohaus
Subject Area
Structural Engineering, Building Informatics and Construction Operation
Term
from 2014 to 2020
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 257623116
In order to build lightweight constructions with concrete, new construction concepts must be developed to substitute the traditional heavy building technique for concrete structures. These construction concepts lead to form optimized constructions (form follows force), but also to new combinations in the material choice in the sense of material follows force. In addition to favorable production conditions, the thought of uniting both of these principles forms the core ideas of the present application. Funa and Flora show that besides the principle of shell, the principle of a tube is one of the most effective methods in natural lightweight construction. The principle of tube is characterized by its hollow circular cylindrical shape. While being loaded there will occur no peaks in the stress distribution, because of its constant curvature. In addition, tubular structures are also characterized by a low ratio between load bearing capacity and weight. This nature phenomenon was taken up in the dissertation Lindschulte and led to the development of highly efficient structures made of high-performance concrete. In this project this phenomenon is used to even advance the structural design by an additional CFRP wrapping. Therefore, the aim of this research project is to develop an optimized design for wrapped hybrid tubes as lightweight structures relating to material and shape. Associated ultimate and residual load calculation methods are included. As a special feature of this design, each individual component in the cross section is assigned a specific role in the process of load transfer. The main component of the structure is formed by a relatively thin core layer of high-performance concrete. The main task of the core layer is to receive the compression stresses. The core is surrounded by an inner and outer steel plate. These steel plates create certain amount of ductility by supporting effects. Additionally the plates serve as a permanent formwork. Own preliminary work have shown that the supporting effect is most effective if the supporting is as soft as possible in longitudinal direction and as stiff as possible in circumferential direction. Such an anisotropic behavior can be achieved by fiber reinforced polymer as a material for an additional wrapping. In order to derive models for the description of the bearing behavior of wrapped hybrid tubes under centric and eccentric normal loads, the three relevant structural components (concrete core, steelplates and CFRP wrapping) are going to be varied in experimental and numerical studies. Material models will be used, that already are successfully used at the LUH for numerical calculations of grouted joints in offshore wind energy constructions. In this way, a new type of lightweight structures made of concrete will be established.
DFG Programme
Priority Programmes
