Engineering analysis and design software
Civil and Structural engineering

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

Rugby cement clinker store under construction

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.

clinker store mesh

clinker store geometry assignments

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.

Long term tendon loading assignments

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-Neilson forces were plotted for both faces to aid reinforcement detailing. By using the Clark-Neilson facility in LUSAS, in plane forces, bending and torsional bending moments are combined into a set of orthogonal forces - ideal for reinforcement design.

clinker store horizontal clark-neilson forces

clinker store vertical out-of-plane shear

Horizontal Clark-Neilson forces Vertical out-of-plane shear forces

 

Rugby cement clinker store under construction

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 Neilson 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 Neilson contour plots produced for each loadcase."

Phil Benson, Oscar Faber


 

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