Design & Engineering
Problem & facts
Due to the complexity and the high number of possible combinations, a complete design
check of different load cases at joints have rarely been provided. Manufacturers
of joint profiles have dealt only with the capacity/resistance of their
products, without considering the ultimate limit design in-situ. The
interaction of subgrade-reaction, concrete and loading combinations has not been
taken into account.
load transfer calculations have been based on the bending and shear of steel
bars or plates connecting adjacent concrete panels. The results inevitably show
that the joint has a lower load capacity (often less than 50%) compared to the
interior load capacity of the concrete slab.
industrial floor itself is always based on a load transfer at joints (usually
around 40% when using load transfer systems), whereby the actual design values for
the load cases “edge” of the floor slab are significantly reduced. However,
this applied percentage is an assumption and up to now, this assumption was
mostly neither checked nor confirmed.
Solution & design
Hengelhoef Concrete Joints in collaboration with International Joint Tech
Engineering s.a. is now able to measure the exact load transfer of the Cosinus
Slide® joint and provide a complete calculation at ultimate limit state for all
relevant loads and combinations. This calculation does not replace the design
of industrial floor slab itself, but completes the part required for joint
profiles, providing an accurate assessment of load transfer at the joint used
in the floor design.
is primarily based on the theory published in Concrete Society Technical Report
34 (4th edition), and has been independently tested and confirmed
using finite element method (FEM).
material capacities were determined in a nonlinear simulation and with
laboratory experiments, and statistically analysed in accordance with EN 1990
Euro code (EC 0). This has provided ultimate capacity values that can be
adapted to the required design level in accordance to the various norms and
guidelines of different countries by using appropriate safety factors.
Practice & outcome
Slide® joint will permit a recommended joint opening of 15 mm, while still
ensuring shock and vibration-free passage of trucks or forklifts (see
certificates of conformity 020238-14-2 to 4). Due to the shape/geometry of the
profile, there is virtually no impact witnessed on the concrete edge when
trafficked by pneumatic and hard plastic wheels. As the concrete “fingers” rest
directly on each other, fatigue effects and failures at the transition between
joint “fingers” and full-depth concrete floor are very unlikely. The Cosinus
Slide® joint profile is therefore compliant with the European directive
2002/44/EC concerning exposure of workers to whole body vibrations. Furthermore
the possibility of free movement of the Cosinus Slide® joint in horizontal
directions and the low friction between slab and ground reduces restraint stresses
to a minimum. Due to the above described facts, the serviceability of the
Cosinus Slide® joint is proven and maintenance costs for the floor slab, the
joint and the forklift wheels are significantly reduced.
with all joint systems, to obtain all the benefits outlined above, it is
crucial to install Cosinus Slide® joint in a professional manner, following the
guidance procedures provided.