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Tests of the capacity of shear connections consisting of nails in a row placed at distances 7, 10 and 14d, “d” being the cross-sectional dimension of the nail, versus single nail capacities, were executed. The performed tests do support the connotation that no reduction should be required for nails of diameter 2.8 mm or less in a row, provided that nails are spaced sufficiently far apart for wood cracking not to occur. At the ultimate capacity of the joint, all such thin nails in a row will be yielding, having developed plastic hinges, i.e. each single nail will have developed its ultimate capacity. Hence, the ultimate capacity of the connection will be each nail’s capacity times the number of nails in the row. The force pr. nail increases subsequent to the development of a plastic hinge. This is likely due to the axial pullout-force, i.e. the ultimate capacity of a shear connection is higher than the force required for developing plastic hinges in the nails. This additional capacity-reserve may also partly be attributed to the rotational resistance of nails. The number of nails in a row should make insignificant difference in the pr. nail capacity, as long as no wood cracking takes place. Thus, applying elastic theory to nails in a row does not seem relevant. This is in contrast to bolt-connections.
On April 15, 2008, six students (aged 16 years) and one teacher (aged 29
years) from a New Zealand school lost their lives in a river canyoning tragedy.
The present study investigated the school principal’s perspective of how he led
his school through the tragedy, and the role of faith in the school’s coping.
The school principal was interviewed two years after the event. The school’s
Christian foundation was the fundamental source of strength and guidance for
the principal, as well as for students, staff, teachers, and families in the
immediate aftermath of the tragedy and in the two years following (i.e., to the
time of the present study), the Christian culture of the school guiding
decision-making. Support from outside the school (e.g. critical incident
support; teaching support from other schools; social support from community
agencies and civic leaders) also played an important role in assisting the
school through the tragedy, particularly in the immediate aftermath of the
event. Further studies are required that allow the voices of children, families
and school staff to be heard regarding leadership strategies that impact on
them through a disaster.
This article presents a study
of configural reasoning and written discourse developed by students of the
National Polytechnic School of Ecuador when performing geometrical exercises of