Timber-Concrete Composite bridges have the potential to achieve significant levels of structural efficiency through the synergistic use of Engineering Wood Products (EWPs) and reinforced concrete. With the implementation of post-tensioned under-deck tendons, the range of application of TCC bridges can be extended to medium spans. However, little work has been done to date to study the dynamic response of these newly proposed bridges. In this paper, a set of FE models representing 60-m span structures are analysed to gain understanding on the dynamic response of post-tensioned under-deck TCC bridges. Two models with Euler and Timoshenko beam idealizations are considered in order to evaluate the significance of shear deformations on deflection, structural stresses and connector shear forces. Besides, an analytical model is formulated and compared against the numerical predictions. The results show that timber shear deformations should be considered in the design of post-tensioned under-deck TCC bridges. The dynamic characteristics of the bridge models were studied. The dynamic amplification caused by a moving point load on key response parameters such as deflection, stresses and connector shear forces is discussed. Also, a sensitivity study on the speed of moving load is conducted to investigate its influence on the bridge dynamic response.
The low carbon footprint and high structural efficiency of engineered wood materials make tall-timber buildings an attractive option for high-rise construction. However, due to the relatively low mass and stiffness characteristics of timber structures, some concerns have been raised regarding their dynamic response. This paper examines the dynamic behaviour of tall timber buildings under tornado and downburst wind loads. It summarizes the results of extensive response history analyses over a suite of FE structural models subjected to different wind actions and compares them with the ISO10137 comfort criteria. In general, large levels of floor accelerations are observed in particular for stiffer medium-rise structures with significant density of walls. It is shown that downburst loading governs the peak acceleration response of medium-rise buildings whilst tornado loading becomes more critical for taller buildings. The effectiveness of TMDs in reducing peak acceleration values is explored. This study emphasizes the need for further studies on the dynamic behaviour of tall timber buildings.
This paper examines the embedment behaviour of single-dowel connections in Scandinavian Spruce Glulam by means of experimental and numerical investigations. First, the experimental results of a series of single-dowel tests on samples of different geometry and grain directions are presented. The evolution of local strain concentrations around the fastener at increasing levels of bearing deformation, is reported in detail by means of non-contact field strain measurements and its implications are discussed. Detailed finite element simulations are also carried out and subsequently employed to highlight the main features of the response of doweled connections in glulam. A foundation model, initially developed for Douglas-fir (Pseudotsuga menziesii) timber, is upgraded and adapted for Scandinavian Spruce Glulam (Picea abies) elements subjected to loads acting perpendicular and parallel to the grain direction. The proposed model is based on the definition of equivalent material parameters for the crushing region around the dowel hole. To this end, relationships for the estimation of material characteristics as a function of the crushing volume are suggested. The validity and accuracy of the proposed modified foundation models are examined against the experimental results. It is shown the improved foundation model is able to simulate the embedment stiffness, capacity and inelastic behaviour of single-dowel connections on glulam with reasonable accuracy for strains of up to 8 %, and can therefore be used for design and assessment purposes.
This paper presents an experimental study into the lateral response of cross-laminated-timber (CLT) shear walls under cyclic loads with particular attention to the distribution of forces between the panel-to-floor connections. Six tests on full-scale specimens of different geometric characteristics and connection configurations are presented. The test set-up and wall configurations are described and a detailed account of the experimental results and observations is presented. The paper examines key response features including stiffness, strength, energy dissipation and ductility. Especial attention is given to an accurate measurement of the load sharing between different brackets and its evolution throughout the cyclic action. The results reported offer valuable information on the lateral forcedisplacement response of CLT walls and the applicability of widely employed design assumptions.