Project Summary
This report presents the outcomes of the literature review and structural concept development phase for a hybrid CLT–LGS–CLT sandwich floor system, tailored to meet the growing demand for high-performance modular construction solutions. With increasing emphasis on sustainability, construction speed, and long-span capability, current modular floor systems face challenges in balancing strength, serviceability, fire performance, and rapid prefabrication.
DBI Partner
A systematic review of over 150 research articles, design codes, and case studies revealed that conventional timber-only floors struggle with vibration comfort and span limitations, while steel-only floors increase floor depth and fire protection costs. Timber-concrete composites (TCC) improve structural and vibration performance but conflict with modularity due to increased weight and reliance on wet trades.
To address these gaps, a novel sandwich flooring configuration is proposed, combining Cross-Laminated Timber (CLT) panels with Light Gauge Steel (LGS) beams. The steel core provides high tensile strength and stiffness, while the CLT layers deliver compressive resistance, damping, and passive fire protection. This system achieves a reduced floor depth (300–350 mm) and is designed for spans up to 12 m in 8.0 m × 12.0 m modular bays.
Innovative features of the concept include:
- Bolt-based cleat connections for quick assembly and future disassembly;
- Screw-fixed CLT skins to enhance diaphragm action;
- Integrated service pathways within floor depth;
- Passive fire protection through timber charring without additional linings.
Initial analytical assessments predict vibration natural frequencies exceeding 11 Hz, satisfying ISO 10137 comfort criteria, while preliminary load assessments show compliance with AS 1170 and NCC requirements.
The final system layout is detailed in Figure 1 (plan view) and Figure 2 (sections A-A to D-D), showing clear structural hierarchy, connection detailing, and modular prefabrication pathways.
This report establishes the technical basis for subsequent experimental testing, numerical simulation, and fire and vibration performance verification, with strong alignment to DBI’s low-carbon, modular innovation objectives.
