Measurement of rolling shear modulus of Cross Laminated Timber: Exploratory study using downscaled specimens under variable span bending tests
The purpose of this study was to measure the rolling shear modulus of Cross Laminated Timber (CLT), which was achieved by conducting 3-point bending tests with variable span using downscaled sandwich specimens. Two types of sandwich specimens were employed: steel-wood-steel (SWS) and wood-wood-wood (WWW). Experimental results from SWS specimens were verified with those predicted from WWW ones through the shear analogy method. Effects of span-to-depth ratio (l/h) and growth ring orientation on rolling shear modulus (GRT) were also examined. It was found that the average deflection of WWW specimens tested at l/h of 6.5 could be well predicted using the shear analogy method based on true elasticity of modulus (Em) and GRT of the cross layer measured using SWS specimens under variable span tests. The results also showed that the cross layer of `in-between' growth ring orientation could gain the higher rolling shear modulus than that of flat sawn or quarter sawn one.
CLT-Steel Composite Floors for Sustainable Multi-Storey Construction
This thesis encompasses the investigation of a novel proposed construction system that pairs Cross-Laminated 
Timber (CLT) floor panels with steel-frame multi-storey construction. 
As a substitute for concrete floors, the promise of CLT lies in its reduced embodied carbon, and its 
lightness, which gives the promise of reduced material usage and a reduction in the environmental 
impact of a multi-storey building overall. 
In addition to clarifying the environmental benefit such a system provides, this thesis seeks to determine 
whether forming composite sections from the CLT panels and the steel beam, can lead to meaningful 
enhancements to the section stiffness in bending. Finite element analysis is applied for this task, 
necessitating first a methodology for modelling CLT to capture its relevant complexities as a material, 
and subsequently incorporation of the behaviour of the joints between structural elements in the 
proposed system, with the key characteristics of the materials and joint models validated against physical 
test data. 
Focusing predominantly on a slimfloor arrangement of panels and beams, the study provides the first 
evaluation of the effective width of CLT floor panels when acting compositely with steel beams, provides 
a prediction for composite action CLT panels and Asymmetric Steel Beams (ASBs) with a series of 
connectors, and identifies areas of development within the system that could bring about increased 
composite benefits. 
The outcomes of the study are that in a slimfloor arrangement with contemporary panels, beams and 
connectors, the composite enhancement is small but measurable, and that with changes and 
development to the system components, much larger composite enhancement effects could be 
generated.
Experimental and Analytical Studies of Failure Modes in Iosipescu Specimens under Biaxial Loadings
This study is concerned with an extension of the traditional Iosipescu shear test to in-plane biaxial stress applications. A Biaxial Stress Test Fixture, which is based upon the original Iosipescu shear test and the Arcan in-plane stress method, is used to characterize mixed-mode failure phenomena in both isotropic (PMMA) and orthotropic (teak) Iosipescu specimens under externally applied biaxial loads. The fixture is used for generating failure data for a wide range of biaxial (dominated by shear) loading conditions. Finite element methods are used to evaluate the stress state at the notch tips (as a function of the notch-tip radius) of biaxially loaded Iosipescu specimens. In addition, a simplistic analytical approach has been applied to estimate the notch-tip stresses at the onset of failure. A high quality failure envelope has been generated for teak under a combination of shear and transverse tensile loading conditions. Results from the finite element analysis show that an absolute numerical evaluation of the stress distribution at the notch tips can be misleading if a linear-elastic material behavior is assumed. However, the analytical approach, which assumes a uniform stress state along the notch-root axis, is found to more accurately represent the notch-tip stresses. Preliminary results strongly indicate the potential of the Biaxial Iosipescu method as a reliable test procedure for biaxial stress applications.