In this work the behaviour of hybrid multi-storey buildings braced with Cross-Laminated-Timber (CLT) cores and shear-walls is studied based on numerical analyses. Two procedures for calibrating numerical models are adopted and compared to test data and application of provisions in current design codes. The paper presents calibration of parameters characterising connections used to interconnect adjacent CLT panels and building cores, and attach shear-walls to foundations or floors that act as eleveted diaphragms. Different case studies are analysed comparing the structural responses of buildings assembled with „standard" fastening systems (e.g. hold-downs and angle-brackets), or using a special X-RAD connection system. The aim is to characterize behaviours of connections in ways that reflect how they perform as parts of completed multi-storey superstructure systems, rather than when isolated from such systems or their substructures. Results from various analyses are presented in terms of principal elastic periods, base shear forces, and uplift forces in buildings. Discussion addresses key issues associated with engineering analysis and design of buildings having around five or more storeys.
The high performance in-plane of cross laminated timber (CLT) panels has created a potential for the use of CLT members act as diaphragms in steel structures. The behaviour of this diaphragm system depends strongly on the connections involved in linking the panels together and to the steel members. A study of the connections at both locations was made using experimental testing of two connection designs for the panel-to-panel case, and the development of a staggered lag screw connection for the panel-to-steel beam case. The results showed good performance for the double spline and fully-threaded inclined screws panel-to-panel connections. The lag screw connection showed high strength, stiffness, and ductility. The CSA Standard O86-09 was found to best predict the strength of both types of connections. Characteristic design stiffness values were presented for the stiffness at low levels of displacement and the initial, elastic stiffness.
Low amplitude cyclic vertical motions of flat floors that humans find unacceptable are commonly caused by impacts resulting from their own activities or those of other people. It is therefore a goal of engineering design to identify and avoid construction methods prone to creation of motions that make floors unserviceable for an intended type of building occupancy. In some instances use of engineered wood products as construction materials results in floors having unacceptable vibration performances. Usually this is because floors exhibit modal frequencies and mode shapes that cause human perceptory organs to resonate or accelerate. This paper addresses vibration response characteristics of one-way spanning floors constructed using widely spaced glulam beams and transverse glulam deck elements. The vehicles for gaining understanding of such systems are experiments and finite element models.
Connections are critical parts of timber structures, transmitting static and dynamic forces between structural elements. Extensive experiments were conducted and detailed Finite Element (FE) models were developed. The experimental results showed that the stiffness and load-bearing capacity of the joints is reduced by post-fabrication wetting and is increased by post-fabrication drying. It was clear from those test results that changes in mechanical properties were greater than could be explained by effects moisture content changes have on material properties. Three-dimensional (3-D) continuum FE models for connection loaded parallel to grain were successfully developed based on analysis of connections having a single ½ inch (12.7 mm) or ¾ inch (19.1 mm) diameter bolt. The model included the nonlinearity of material and contact analysis between wood and steel and revealed that the connection capacity can be well predicted by using FE techniques.
International Conference on Structures and Architecture
Structures and Architecture: Beyond their Limits
Proceedings of the Third International Conference on Structures and Architecture (ICSA2016), July 27-29, 2016, Guimaraes, Portugal
In the last twenty years CLT (cross-laminated timber) panels have become quite widely employed to build multi-storey buildings often characterized by the presence of many internal and perimeter shear walls. Building superstructures in which beam-and-column frameworks resits effects of gravity loads and core substructures and exterior CLT shear walls resist effects of lateral forces have been found structurally effective. Advantages of such structural arrangements can include creation of large interior spaces, high structural efficiency, and material economies. Here the behaviour of multi-storey buildings braced with CLT cores and additional CLT shear walls is examined based on numerical analyses. Two procedures for calibrating numerical analysis models are proposed and discussed here. The first approach is to use information from Eurocode 5, and the second approach is to use specifically applicable experimental data obrained through laboratory studies. Technically different ways of connecting CLT panels in order to obtain suitably stiff horizontal diaphragms are also presented.
The behaviour of multi-storey buildings braced with Cross-Laminated-Timber (CLT) cores and additional shear walls is examined based on numerical analyses of various 3-dimensional configurations. Two ways of calibrating numerical model are proposed according to codes and experimental test data respectively, including calibration of parameters that characterise connections between CLT panels in building cores and shear walls. Results of analyses of entire buildings are presented in terms of principal elastic periods, and base shear and up-lift forces. Discussion addresses primary issues associated with behaviour of such systems and modelling them.
This paper related to elimination of the deficiencies. The behaviour of multi-storey buildings braced with cores and CLT shear walls is examined based on numerical analyses. Two procedure for calibrating numerical analysis models are proposed using information from Eurocode 5  and specific experimental test data. This includes calibration of parameters that characterise connections between CLT panels and other CLT panels, building cores and shear walls. The aim is to make the characterizations of behaviours of connections that reflect how those connections perform within complete multi-storey superstructures, rather than in isolation or as parts of substructures. The earthquake action for cases studied was according to Eurocode 8  and using the appropriate behaviour factor (q factor). Results of analyses of entire buildings are presented in terms of principal elastic periods, base shear and up-lift forces. Discussion addresses key issues associated with behaviour of such systems and modelling them. Obtained results permit creation of appropriate guidelines and rules for design of the aforementioned types of hybrid buildings incorporating CLT wall panels.
Innovations in timber engineering have led to new slab systems built from engineered wood products like cross-laminated-timber (CLT). High stiffness of CLT can enable attainment of better vibration performances than is possible with traditional shallow profile-long span floors constructed from timber and other materials. However, realization of this depends on engineers being able to accurately predict effects various construction variables have on dynamic responses of CLT slabs. Past physical experiments have provided insights into those effects. However, testing is a very expensive and time consuming means of acquiring necessary knowledge. Discussion here addresses finite element (FE) simulations as a cost effective method allowing engineers to understand and assess relationships between design variables and dynamic responses of CLT floor slabs. Presented modelling techniques are verified by demonstrating close correlation between numerical predictions and experimental modal response characteristics of CLT slabs.
Vibration serviceability of various types of timber floor systems has claimed much attention during past decades. Yet the definition of robustly reliable engineering design approaches has remained elusive, except in well-defined situations. Successful de...