Starting point / motivation

Concrete is a key lever for decarbonization: cement production accounts for around 8% global CO₂ emissions. In multi-storey buildings, 40 to 60% of the concrete volume is used in floor slabs—yet flat slabs use material inefficiently, as concrete in tension zones provides no structural function. Timber–concrete composite (TCC) slabs address this inefficiency by placing timber in tension.

Digi-HBV combines circular design (Rethink, Reduce) with digital planning and prefabrication: modular precast elements with demountable joints for reuse, short construction times, and minimal on-site moisture; a material-conscious design with concrete confined to the compression chord and timber panels forming the tension chord and ribs.

Contents and goals

The goal is to halve manufacturing-related environmental impact (> 50% versus RC flat slabs, Ökoindex 3) and ensure circularity through demountable connections. Research questions address:

• LCA benefits of generative design compared to RC and conventional TCC solutions.
• Load-bearing capacity and durability of interlocking, CNC-milled timber dowels for the timber–concrete interface.
• Achieving diaphragm action via a demountable joints.
• Predicting long-term behavior (mechano-sorptive creep) under real climatic conditions.

Core work: a seamless file-to-factory workflow with integrated structural design and LCA, automated production data, novel connection details, and validation on four large-scale demonstrators.

Methods

The partners combine complementary strengths across defined work packages. The research unit Structural Concrete designs the TCC slab concept (AP2), integrates robust LCAs, and transfers them into a seamless file-to-factory workflow (AP4), while developing and experimentally validating connection details (AP3).

The research unit Structural Simulation and Timber Engineering develops a numerical model for long-term deformation prediction (AP3), calibrates it with connection and large-scale tests (AP3, AP5), and integrates timber-specific verifications into the digital workflow (AP4) and simulations of full-scale tests (AP6).

DataB programs the joint digital production process (AP4), fabricates CNC-milled timber components for small-scale tests and demonstrators (AP3, AP5), and feeds practical requirements for prefabrication, assembly, and reuse into the element design (AP2). Validation relies on large-scale demonstrators and laboratory tests (AP5, AP6) with benchmarking to robustly achieve at least a 50% reduction in manufacturing emissions.

Expected results

• Sustainability: Proof of at least 50% reduction in manufacturing emissions compared to conventional systems.
• Engineering: Validated, metal- and adhesive-free shear connection; demonstrated diaphragm action via demountable joints; robust, scalable prefabrication and assembly.
• Digital workflow: Integrated design-to-production with shorter lead times, fewer errors, and high variant flexibility.
• Predictive capability: Calibrated long-term model for moisture/creep, surface protection, and production parameters.

Project management

TU Wien - Institute of Structural Engineering, Research Unit Structural Concrete

Project or cooperation partners

• TU Wien - Institute of Mechanics of Materials and Structures, Research Unit Structural Simulation and Timber Engineering
• DataB GmbH

Dr. Tobias Huber
Karlsplatz 13/E212-2
A-1040 Vienna
Tel.: +43 (1) 58801 21242
E-mail: tobi.huber@tuwien.ac.at
Web: www.tuwien.at/cee/tragkonstruktionen/beton