CONTENT 5.1 SEISMIC BEHAVIOUR ... - CIB-W18

5.1 SEISMIC BEHAVIOUR
17-15-2 K F Hansen
Seismic design of small wood framed houses
It is to be expected that European manufacturers of one-family houses to a
growing extent will seek new markets abroad and so in many cases will
face the requirements that the houses must be able to withstand earthquakes.
A particularly suitable type for earthquake areas is timber framed
houses with a sheathing of for example plywood, particle boards, fibre
boards, plasterboards or similar materials.
In this paper first a qualitative description is given of the forces induced
in a house during an earthquake. The general rules for the design of earthquake-proof
houses are listed and a method for taking up the forces in
panelled timber framed houses based on vertical shear walls and horizontal
diaphragms is described. The last chapters of the report deal with the general
requirements to be met when designing the structural elements and
joints of the house and what steps to take to ensure that the statically secondary
elements of the house can withstand seismic vibrations.
Supplementary to the general advice and instructions of the report the
Appendix contains guidelines on design of panels subjected to forces in
their own plane.
Requirements for non-bearing structures and secondary structures
If a building is designed and built as a shear wall structure, the relative
movements between the various parts of the building are small and the
damage from these relative movements on secondary structures, nonbearing
walls, windows, doors etc. will therefore, be relatively small. In
spite of this, details by windows, etc. should be made in such a way that it
is possible for a wall to deflect without the window getting a similar deflection
in order to avoid broken window panes. A gap of at least 1/8" ~ 3
mm between wall and window is recommended. For non-bearing walls it
would be prudent to build in a certain gap, too.
Even if the shear wall structure reduces the relative deflections among
the bearing structural parts, it can of course not avoid that all parts within
the house are exposed to the earth tremors.
The following rules serve to reduce the unfortunate consequences of these
tremors.
– Cupboard, like boot, cases, closets etc. ought to be screwed (not, nailed
to the walls. Closets should be provided with a positive locking device.
– Brick chimneys and fire places as well as heavy partitions should be
avoided.
– Stoves, boilers and similar, heavy objects must be properly secured to
floors and walls, and they should be placed as low as possible.
– Any gas installation must have an easily accessible closing valve.
18-15-1 A Ceccotti, A Vignoli
Full-scale structures in glued laminated timber, dynamic tests: theoretical
and experimental studies
Abstract
This paper presents the results obtained by application of a particular
methodology of dynamic tests being carried out on full-scale assembled
timber structure, analysing in particular the theoretical approach and the
importance of results obtainable from experiments.
Introduction
Factory control
In Italy quality control on glued-laminated timber is usually conducted by
checking single structural elements while they are being manufactured in
factories. This involves first of all the quality control of machinery and
staff training, followed by the checking of gluing in the finger joints
(bending tests) and between one lamina and another (shear tests) according
to statistics.
Assembly Field control
Checks in the finished structure are left to the discretion of the "Direttore
dei lavori" ( Chief Resident Engineer) firstly, and the "collaudatore" (Testing
Engineer) , secondly. They have the right to carry out tests that they
consider suitable both before assembly as well as after assembly in order
to check the quality of the materials themselves and to check the structural
diagram provided by the designer.
Without entering upon the various problematics that appear at this
stage, from now on we would like to concentrate on the particular aspects
CIB-W18 Timber Structures – A review of meeting 1-43 5 SPECIAL ACTIONS page 5.5