Earthen building 2.0: Earthen building of the future - The art of craftsmanship based on engineering approaches

Starting point / Motivation

The construction sector is one of the largest CO2 emitters worldwide, making the reduction of emissions in this area crucial for achieving global sustainability goals. The use of clay as a building material offers a promising solution to reduce CO2 emissions and the consumption of grey energy.

Clay is attractive not only because of its environmentally friendly properties such as easy availability and reusability but also because it offers economic benefits by being used as a byproduct of construction sites. Despite these advantages, clay is rarely used in modern architecture, among others due to the lack of standardized design and calculation methods.

Contents and Goals

The research project focuses on the suitability of fiber optic sensors (FOS) for monitoring the deformation behavior of rammed earth wall elements under various conditions. The effects of moisture and temperature fluctuations, known as shrinkage, and changes in shape due to loads, known as creep, are investigated.

Using FOS, these deformations will be measured non-destructively and over the long term. The collected data will be used to develop a finite element model (FEM) to simulate failure mechanism under load.

The goal is to better understand the long-term deformation behavior of rammed earth structures and integrate it into structural design. This will improve safety and enable realistic calculation and dimensioning of load-bearing rammed earth walls in 3D building models.

The project includes three research questions:

1. the suitability and integrability of the material properties experimentally determined from small samples feasible for FEM,
2. the applicability of FOS for long-term monitoring in rammed earth wall elements,
3. the measurement accuracy of FOS in rammed earth wall elements.

Methods

The methodological approach is divided into two main areas: experimental investigations and theoretical modeling. Experimentally, the moisture and temperature-dependent deformation behavior is investigated using distributed fiber optic sensors (DFOS). In the theoretical part, the experimental data will be used to develop a numerical model using the finite element method (FEM), which simulates the load-bearing and failure behavior of rammed earth components under load.

Expected Results

The research project investigates the possibility of long-term, non-destructive monitoring of the shrinkage and creep behavior of rammed earth wall elements using fiber optic sensors (FOS) to determine their suitability for permanent in-situ measurements. The practicality of these sensors for accurately capturing deformations under various conditions such as moisture and temperature changes, as well as mechanical loads, will also be evaluated.

The experimental findings will be incorporated into a finite element model that simulates failure behavior under load. This research project contributes to the development of more precise calculation methods for the structural design of rammed earth structures, thereby increasing the safety and reliability of this construction method.

Overall, the project aims to provide a deep understanding of the long-term behavior of rammed earth under real conditions and lay the foundation for more advanced construction and monitoring techniques.

Project management

Graz University of Technology - Institute of Structural Design

Project or cooperation partners

• Graz University of Technology - Institute of Engineering Geodesy and Measurement Systems
• Graz University of Technology - Laboratory for Structural Engineering

Graz University of Technology – Institute of Structural Design
Assoc.Prof. Dipl.-Ing. Dr.nat.techn. Andreas Trummer
Technikerstraße 4/4
A-8010 Graz
Tel.: +43 (316) 873 6211
E-mail: andreas.trummer@tugraz.at
Web: www.ite.tugraz.at