Between July 15th and 19th 2012 will be held the World Conference on Timber Engineering in Auckland, New Zealand. This event will be hosted by both New Zealand and Australian timber engineers. It is the next one in a series of world timber conferences that have taken place in Italy, Japan, US (x2), Finland, Malaysia, Canada, Switzerland, England in the last 20 or so years.
Such an event will attract close to 600 delegates from all over the world. This upcoming one has generated such interest that over 450 abstracts have been accepted and there will be close to 300 oral presentations from delegates from 36 different countries on topics that range from connections issues to lateral load systems to future issues. The conference is spanning three full days, each having its own theme and key note speaker.
The theme for the Monday is Practical engineering problems and solutions and the keynote speaker is the world-renowned Prof Dr.-Ing Hans Blass from the Karlsruhe Institute of Technology. Professor Blass has by extensive research, provided fundamental engineering knowledge on timber connections and converted this knowledge to usable format for practising engineers based on principles of mechanics. He has also developed methods for designing connectors and connections and plays an important role in the international standardization of these methods. Professor Blass has pioneered the application of self-tapping screws in timber constructions, promoting the manufacturing of very large screw dimensions and developing and introducing these connections for high load applications. This work has led to much simplified methods for repairing damaged beams and reinforcing new ones. The development and introduction of efficient connections which are easy to install make it possible to construct large timber structures and save timber material while offering attractive logistic solutions by use of prefabricated elements. The developments made by Professor Blass have been of importance for the increased use of larger wood based construction elements such as glulam, which in Europe has increased in use by more than four times since the mid-1990s.
Prof Blass's keynote lecture will cover the topics of glulam beam reinforcement and of optimized timber trusses and connections using adapted cross-laminated panel technology. He will demonstrate that to overcome the problems related to the low glulam shear and tensile strength perpendicular to the grain, two different approaches can be used: the first approach replaces glulam by cross-laminated timber members where the vertical cross layers in beam elements provide a continuous reinforcement; the second approach tackles the main problem areas of timber trusses. Prof Blass's proposes to use bending members of cross-laminated timber arranged edgewise, so that the cross layers decrease the load-bearing cross-section parallel to the member axis. The arrangement of several parallel timber boards over the width of the cross-section thus leads to a much larger homogenization effect than for glulam, where the tensile capacity of the lowermost lamella in general determines the bending strength. The load sharing between the parallel boards in cross-laminated bending members increases the bending strength and compensates for the loss of cross-section due to the cross layers. The cross layers further act as integral reinforcements for notched beam supports, holes in beams, for load components perpendicular to the member axis or in apex areas of double pitched members. As for the issue of optimisation of the connections in trusses, separate solutions for tensile and compressive diagonals will be shown. For tensile members, cross laminated timber with about 80 % longitudinal and 20 % cross layers can be used, where screws in pre-drilled holes are arranged parallel to the member axis and only within the cross layers. Consequently, the full screw tensile and withdrawal capacity is available while the ratio of net to gross cross-section remains 80 %. For compressive members a new type of contact joint produced by computer controlled joinery machines will be shown which has very high load-carrying capacity and only slightly affects chord cross-sections. The two examples for improving the performance of structural members for timber roof structures show that the present problems and product limitations for larger glulam members or trusses may be overcome by practical engineering solutions.
The theme for the Tuesday is Design for Extreme Events and the keynote speaker is the Canadian structural timber engineer Robert Malczyk from Vancouver. Robert studied timber engineering under the supervision of the late Professor Borg Madsen, inventor of the now widely used timber rivet. He started his professional career with the Vancouver-based firm of J. Novacek and Associates and in 1998, co-founded the Vancouver design firm of Equilibrium Consulting Inc. He has pioneered the use of proven, state-of-the-art timber technologies in Canada and helped raise the local industry's awareness and sophistication through the execution of a string of innovative and architecturally notable timber structures. Robert has since contributed to over 500 projects, several of which have received awards. He is known for his creative approach, cost effective designs and commitment to the development of architecturally integrated detailing. Robert has a broad field of expertise and successful experience, including renovation work, upgrades and new construction, on projects with very limited budgets as well as high profile architecturally oriented public projects, large and small. Robert is a recognized expert in the field of timber engineering and has undertaken numerous technical presentations at conferences and universities including the College of New Caledonia and the University of British Columbia. Robert is also a regular nationwide lecturer for the Canadian Wood Council Woodworks! Program, and a member of the Canadian timber code technical committee (Engineering Design in Wood - O86).
Robert's keynote lecture is titled Post Disaster Serviceability Issues for Timber Buildings. Currently, typical structural designs do not directly address the post disaster serviceability issues of timber buildings. Drift limits for wind and seismic design are the only requirements that address excessive deformations together with deflection limits on bending members. Various building codes around the world identify protection of life as the primary objective during a strong seismic event, followed by limiting building damage after a moderate strength earthquake. Only buildings which are designated as post-disaster are required to remain functional with minimal damage following a strong ground shaking. The resulting impact of these requirements on the structural engineering design practice is that a typical engineer does not address any additional post disaster serviceability issues unless it is specifically requested by the owner, as in the case of post disaster buildings. The latest Canadian timber design code, still not referenced by provincial codes, introduces the procedure of capacity design to timber structures. Shear walls are identified as the desired energy dissipation elements, while diaphragms are designed for larger seismic forces followed by the drag struts and connectors that are to withstand an even higher level of force. This is the first step in identifying and properly detailing elements of sufficient stiffness that can provide inelastic energy dissipation. Most structural engineers design their buildings intuitively to have enough ductility so the structure can deform in-elastically under seismic load with limited loss in strength. This can only be achieved by careful detailing of selected energy dissipating elements, which are designed as per capacity design principles that are currently being introduced in timber design codes. The currently used force-based system of seismic design assumes that different elements can be forced to yield at the same time which rarely happens in real buildings. Additionally, present building codes do not specify requirements to limit the damage resulting from yielding of energy dissipation elements. Robert will show that recently new design methods have been developed to address these issues. As a displacement capacity is more important in seismic behaviour than strength of the elements, these new methods start with deformation instead of the force. The structures are designed so they can reach the specified deflection levels under design earthquake, rather than for a seismic lateral force that results in a deformation level that is to be less than a code limit. One of the new methods: Direct Displacement-Based Design (DDBD) is becoming the most popular because of its simplicity, wide applicability and ease of incorporation in to design codes. Robert will also show that timber structures can only achieve a ductile response if the connections can behave in-elastically. Therefore, the first types of timber buildings that are being designed by DDBD method use plywood and wood framing shear walls, ductile moment resisting frames and post tensioned multi story systems. As always in timber engineering, the ductility of connection systems remains the key for a successful performance of the whole system.
The theme for the Wednesday, the architects' day, is Creative Use of timber products and the keynote speaker is the architect Peter Busby, Managing Director of Perkins+Will, one of the largest design firms in North America who have successfully delivered an impressive range of significant international projects across all sectors. As a director of Perkins+Will since 2004, Peter's role includes sustainable design leadership to the firm's 23 offices worldwide and Perkins+Will have been recognized internationally as the leader in sustainable building design. Peter is a founder and recent Chair of the Canada Green Building Council, and he has devoted much of his time to his profession, to the community, and to the advancement of sustainable education and practices. As Managing Director, Peter is involved in the design and sustainable direction of each project the firm engages. Peter directs more than 100 employees working on projects across Canada, the United States, Europe, and the Middle East. Timber is a material that features strongly in the most recent cutting edge, sustainable Perkins+Will buildings. As Peter notes, "Wood is a renewable building material made by the sun. Trees are a major vehicle on the globe to reduce carbon," he says. "They're our ally in keeping the biosphere healthy." Peter provides extensive experience in leading large-scale sustainable urban planning projects including four framework master plans for the Emirate of Abu Dhabi, Victoria's Dockside Green and the master plan for the new Edmonton City Centre Redevelopment in Canada. With over 30 years of successful projects completed under Peter's guidance and across market sectors, the firm has received more than 100 design honours.
To close the conference on the Thursday, the theme of the day is future of timber engineering.
In addition to these three world-renowned speakers, 294 others will be presenting on various topics related to the above mentioned themes. As in the past such event, many papers on connections and lateral load resisting systems will be presented. All in all, there will be six parallel sessions at all times.
More information can be found at wcte2012.com