Folded Plate structures
- 1. FOLDED PLATE STRUCTURES Rohan Joshi -Assignment 4
- 2. Folded plate structures Folded plates are assemblies of flat plates rigidly connected together along their edges in such a way that the structural system capable of carrying loads without the need for additional supporting beams along mutual edges. Modern folded plate structures are typically made of cast in situ or precast reinforced concrete, or steel plate. There are several benefits of folded plate construction. They are simpler to manufacture than other shells such as cylindrical shells, with relatively simple formwork required, and usually use less material. However, folded plates require more materials than curved shells since there is normally more bending involved. Folded plate structures have an intrinsic rigidity and high load-carrying capacity which makes them economical over long spans that need to be free of internal columns and other obstructions.
- 3. FOLDING SYSTEMS IN NATURE The principle of folding as a tool to develop a general structural shape has been known for a long time. Folded structure systems which are analogous to several biological systems such as found at broadleaf-tree leaves, petals and foldable insect wings, are adopted to be employed in a new, technical way. Leaf of PalmTree Beetle InsectWith Foldable Wings Seashell THE PRINCIPLE OF FOLDING The structural characteristics of folding structures depend on: • The pattern of the folding. • Their geometrical basic shape. • Its material. • The connection of the different folding planes. • The design of the bearings. • Movable form work can be employed. • Form work required is relatively simpler. • Design involves simpler calculations.
- 4. STRUCTURAL BEHAVIOR OF FOLDING Structural Condition Of Folding Structures Load Distribution process : • At first, the external forces are transferred to the shorter edge of one folding element. • There, the reaction as an axial force is divided between the adjacent elements. • Then the forces transferred to the bearings.
- 5. TYPES OF FOLDED STRUCTURE Based on geometric shape folded structures can be divided into: • folded plate surfaces structures : o prismatic: rectangular plates. o pyramidal: non-rectangular plates. o prismoidal: triangular or trapezoidal plates • folded plate frames structures • spatial folded plate structures Geodesic Dome Tapered Folded Plates Folded plate rigid frames
- 6. BASIC ELEMENTS OF FOLDED PLATES: • The Inclined Plates. • Edge plates which must be used to stiffen the wide plates, • Stiffeners to carry the loads to the supports and to hold the plates in line. • Columns to support the structure in the air. TAPERED FOLDED PLATES: Folded plate structures may be built with tapered elements and only one of the many possible combinations is shown here. The height of the shells at the center of the span is the critical dimension for bending strength. therefore, the structure is not very efficient and not suitable for long spans because of the excess height required for the large ends. Another weak element in this design is the transfer of shear from the small end of the triangular plate to the large end. if a large number of units are used in each span, the transfer of loads may be difficult. A folded plate may be used for walls as a thin structural element by casting each plate flat on the floor and grouting the joints full of concrete. a wall of this type can be made much thinner than a flat wall.
- 7. FOLDED PLATETRUSS: • The term "folded plate truss" is intended to indicate the structural action of this structure. There are horizontal ties across the width only at the ends of the building. • The thrusts from the triangular crossed arches are carried lengthwise to the ends. • The top chord of the inclined truss is formed by the ridge member. • The bottom chords are the ties at the base of the side gables and the diagonals are formed by the sloping valleys at the intersection of the gables and the triangular plates. • This is truly a space structure and its structural action is as shown and, therefore, the architectural appearance is mote subtle that the usual shell structure. FOLDED PLATE RIGID FRAME: • An arch with straight segments is sometimes called a Rigid Frame. • It is not as efficient as the curved arch because the bending moments are greater. • Ties across the plates are required at the knees and at the crown in order to distribute the forces at the ends of each segment.
- 8. EDGE SUPPORTED FOLDED PLATES: The usual upturned edge plate can be eliminated and the roof structure can be made to appear very thin if the edge plate is replaced by a series of columns. The slab between columns must be designed as a beam and it may be convenient to extend the main roof slab as a Cantilever Canopy. The beam element that carries the load of the roof between columns will then be wider and windows under the slab will have the same function as in the previous examples of folded plates. Note the vertical columns in the end walls at the crown of the gable. these take the reactions of the plates and the horizontal ties may be eliminated. wind loads are taken by rigid frame action in the Columns and Stiffeners. THREE SEGMENT FOLDED PLATE: The forces from the reactions of the sloping plates on these rigid frames will be quire large and at an outside column they will not be balanced by thrusts from the adjacent plates. The size of the frames may be reduced by using a steel tie between the tops of the columns which can be concealed in the fenestration. The dimensions of the plates are dependent on both the width of the barrel and on the span. The depth of the shell should be about 0.10 times the span and the maximum slope of a plate should not be greater than 40 degrees.
- 9. APPLICATIONS OF FOLDED PLATE STRUCTURES As a roof, Sport’s Gymnasium, Brazil As a wall, Air force Academy Chapel, Colorado As a floor structure, floor decking As sheet piles, securing the foundation pit
- 10. References • https://www.slideshare.net/RohanNarvekar2/folded-plates • https://www.researchgate.net/publication/281395871_Folded_structures_in_modern_architec ture • https://structurae.net/en/structures/buildings/folded-plate-structures • https://encyclopedia2.thefreedictionary.com/Folded+Plate+Structure • https://www.designingbuildings.co.uk/wiki/Folded_plate_construction#:~:text=Folded%20pl ate%20structures%20are%20assemblies,supporting%20beams%20along%20mutual%20ed ges.