Case Study
UK's largest
clinker store designed using LUSAS
- Evaluation of pre-stress load
transfer
- Prediction of induced
loadings and displacements
- Static, soil-structure and nonlinear
analysis
LUSAS Civil & Structural analysis software
has
been used by consulting engineers Oscar Faber to predict induced loadings and subsequent
deflections on the wall and foundations of a 120000 tonne capacity post tensioned clinker
store for Rugby Cement. The store is part of a design and construct contract let to Bierrum and Partners Limited by AMEC Construction
Limited and with an internal diameter of 55 metres, a wall height of 35 metres and a roof
height of 54 metres, the store is the one of the largest in the world.
With a wall thickness of 500mm, the store is relatively
thin walled and being post tensioned required a full 3D geometric nonlinear analysis using
LUSAS to prove the design. Thick shell elements of various thicknesses modelled the store
wall, upper ring beam, tendon anchorage pillasters and foundation. Beam elements modelled
steel stiffening frames around conveyor openings. 2D plane strain and axisymmetric
analyses of the soil / structure interaction were done initially to assess the effect of
the weight of stored material on foundation rotation. The results obtained were then used
to specify spring support conditions to the base of the wall in the 3D analysis.
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|
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| Finite
element model |
Geometric
assignments |
Eccentric
discharging of clinker using underground conveyors causes uneven pressure loads against
the wall of the store. Assessment of this non-uniform partially-full situation together
with other load cases such as loads at pre stress transfer, wind loading on the empty
store before and after post tensioning, and a full store with long term tendon loads were
the key to obtaining a full understanding of the response of the structure.
LUSAS Civil
& Structural provides comprehensive results processing facilities. The use of a
variety of contouring features clearly illustrated the effects of the different loading
considered. Contour plots showing forces, bending moments and out of plane shears in the
wall and foundation were produced. Deflection plots showed model deformation under each of
the applied loads. For each load case horizontal and vertical
Clark-Nielsen forces were
plotted for both faces to aid reinforcement detailing. By using the
Clark-Nielsen facility
in LUSAS, in plane forces, bending and torsional bending moments are combined into a set
of orthogonal forces - ideal for reinforcement design.
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|
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| Horizontal
Clark-Nielsen forces |
Vertical
out-of-plane shear forces |
By making use of LUSAS Civil & Structural analysis Oscar
Faber obtained a comprehensive set of results that showed the behaviour of the store under
all loading conditions. "LUSAS modelled the stress stiffening effects on the store
very well", said Phil Benson of Oscar Faber. "The details given on foundation
movement and stresses at tendon jacking points were of particular use to us in proving the
design. LUSAS helped us to save design time and allowed us to produce a more efficient
reinforcement arrangement due to the Clark-Nielsen contour plots produced for each
loadcase."
"The details given on foundation
movement and stresses at tendon jacking points were of particular use to us in proving the
design. LUSAS helped us to save design time and allowed us to produce a more efficient
reinforcement arrangement due to the Clark-Nielsen contour plots produced for each
loadcase."
Phil Benson, Oscar
Faber
Find out more
Other LUSAS Civil &
Structural case studies:
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