CONTENT 5.1 SEISMIC BEHAVIOUR ... - CIB-W18

uhe. The shear walls were tested following ISO/CD 21581 [3] while assuming
boundary conditions reflecting the intended construction details. In
this paper the test results are presented and are compared with test results
of conventional timber frame walls.
Discussion and future prospects
All tests were carried out using ISO/CD 21581 [3]. Boundary conditions
were assumed to reflect the actual building conditions. At high vertical
loads the shear capacities were achieved. The practicability of ISO/CD
21581 [3] is determined; the applicability also for exceptional timber construction
systems is proven.
The system with PFTE showed good performance in monotonic and
cyclic testing as well. In monotonic tests the results for maximum horizontal
load and for stiffness values are quite similar to conventional timber
frame systems.
PFTE showed excellent results for the energy dissipation in cyclic loading,
enlarging its potential range of application to seismic and windstorm
prone areas. Further work is being done to improve the hold-down of the
vertical tensile studs. The PFTE system can cover the same application
range as conventional timber frame buildings, yet it is easy to handle and
therefore cost effective.
Future research work will be developing a finite-element model to simulate
the system properties and to give basics to be implemented in codes.
42-15-2 M Popovski, E Karacabeyli, Chun Ni, G Doudak, P Lepper
New Seismic design provisions for shearwalls and diaphragms in the
Canadian standard for engineering design in wood
Abstract
This paper summarises the newly developed seismic design provisions for
shearwalls and diaphragms that were introduced in the 2009 edition of the
Canadian Standard for Engineering Design in Wood (CSA O86). The new
provisions address seismic design loads for wood diaphragms, shearwalls,
anchor bolts, hold-down connections, shearwall-to-diaphragm connections
and similar load transfer elements. In addition, the provisions include
clauses for wood-based diaphragms used in hybrid buildings with masonry,
concrete, or steel vertical seismic force resisting systems (SFRSs). Two
different design approaches are provided: a) cases when diaphragms may
yield; and b) cases where diaphragms are stiff and are not expected to
yield. The new design provisions have significantly improved the alignment
of CSAO86 with the current 2005 edition of the National Building
Code of Canada (NBCC), as well as with the upcoming 2010 edition of
NBCC.
Conclusion
The paper describes in detail the newly developed seismic design provisions
for shearwalls and diaphragms that are included in the 2009 edition
of the Canadian Standard for Engineering Design in Wood (CSAO86,
2009). The new design provisions have significantly improved the alignment
of CSAO86 with respect to the current 2005 edition of the National
Building Code of Canada (NBCC), as well as with the upcoming 2010
Edition of NBCC.
43-15-2 P Schädle, H J Blass
Influence of different standards on the determination of earthquake
properties of timber shear wall systems
Introduction
Shear wall tests on two modern timber construction systems were carried
out by Karlsruhe Institute of Technology (KIT). Regarding test results
such as stiffness, horizontal load-carrying capacity, hysteresis shape and
hysteresis equivalent viscous damping ratio, all results are similar to or
even better than the well-known timber frame system. This means that
both systems should also be suitable for the use in seismic active areas.
Innovative systems usually do not fit into the design concepts according
to Eurocode 8 (EC8), thus their behaviour factor cannot be found there.
The only approach to classify systems into a ductility class specified in
EC8 is the declaration of a static ductility. This is insufficient because important
characteristics like the energy dissipation and the boundary conditions
of the tests are not taken into account. Since no uniform standard for
the determination of seismic properties of timber construction systems exists,
several problems are identified.
Following from the insufficient static-ductility-approach, the ductility
classes for the systems would be too conservative. Thus the evaluation of
the behaviour factor q for the tested systems was carried out using a numerical
simulation, taking into account the essential properties of the sys-
CIB-W18 Timber Structures – A review of meeting 1-43 5 SPECIAL ACTIONS page 5.28