Independent thesis Advanced level (professional degree), 20 credits / 30 HE credits
The aim of this thesis was to study the load bearing capacity of anchor plates, used
for anchorage to concrete located at nuclear facilities. Two different type of anchor
plates were examined, which together constitute the majority of the anchor plates
used at Forsmark nuclear facility in Sweden. The first is a cast-in-place anchor plate
with headed studs and the second is a post-installed anchor plate which uses sleevetype
expansion anchors. Hence, anchors with both a mechanical or a frictional
interlock to the concrete were examined. The main analysis tool was the finite
element method, through the use of the two commercially available software packages
ABAQUS and ADINA and their non-linear material models for concrete and steel.
As a first step, the numerical methods were verified against experimental results
from the literature. However, these only concern single anchors. The results from
the verifications were then used to build the finite element models of the anchor
plates. These were then subjected to different load combinations with the purpose
to find the ultimate load capacity. Failure loads from the finite element analyses
were then compared to the corresponding loads calculated according to the new
European technical specification SIS-CEN/TS 1992-4 (2009).
Most of the failure loads from the numerical analyses were higher than the loads
obtained from the technical specification, although in some cases the numerical results
were lower than the technical specification value. However, many conservative
assumptions regarding the finite element models were made, hence there might still
be an overcapacity present. All analyses that underestimate the failure load were
limited to large and slender anchor plates, which exhibit an extensive bending of the
steel plate. The bending of the steel plate induce shear forces on the anchors, which
leads to a lower tensile capacity. In design codes, which assume rigid steel plates,
this phenomenon is neglected. The failure loads from all different load combinations
analysed were then used to develop failure envelopes as a demonstration of a useful
technique, which can be utilised in the design process of complex load cases.
2011. , 159 p.
anchor plates, headed studs, expansion anchors, concrete, finite element analysis, non-linear material models, failure envelopes