Folded plates

Study of Folded Plates for understanding their use, types, technology along with suitable case studies. This is a specific type of Methodology adopted for construction over long spans column free spaces. How structurally Folded plates surpases the need of column grids and conventional methods of construction with the proper design and technology is the motive of this study.

1. FOLDED PLATES Group Members: Rohan.S.Narvekar (37) Saurabh.S.Kadam (23) Aniket.S.Manjardekar (33) Aditya.M.Patil (42) Abhijit.D.Nayak (38) Alekh.Patil (43) SUBJECT: THEORY OF STRUCTURES

2. WHAT ARE FOLDED PLATES? 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. Engineer Eudene Freyssinet performed the first roof with the folded structure in 1923 as an aircraft hangar at Orly Airport in Paris. 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 Palm Tree Beetle Insect With Foldable Wings Seashell

3. 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. The Concept Of Stiffness Generation

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. Classification of folded structures based on the material they are made of: Folded structures made of reinforced concrete Metal folded structures Folded structures of wood Folded structures of glass Folded structures of plastic materials Folded constructions made in combination of different materials

5. TYPES OF FOLDED STRUCTURE Based on geometric shape folded structures can be divided into: Folded plate surfaces structures : Prismatic : Rectangular plates. Pyramidal: Non-rectangular plates. Prismoidal : Triangular or trapezoidal plates Folded plate frames structures Spatial folded plate structures TAPERED FOLDED PLATES FOLDED PLATE RIGID FRAME GEODESIC DOME

6. BASIC ELEMENTS OF FOLDED PLATES: The I nclined P lates. E dge plates which must be used to stiffen the wide plates, S tiffeners to carry the loads to the supports and to hold the plates in line. C olumns to support the structure in the air.  TAPERED FOLDED PLATES: F olded plate structures may be built with tapered elements and only one of the many possible combinations is shown here. T he 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. A nother 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. T C

7. FOLDED PLATE TRUSS : T he term "folded plate truss" is intended to indicate the structural action of this structure. T here 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. T he top chord of the inclined truss is formed by the ridge member. T he 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. C

8. FOLDED PLATE RIGID FRAME : A n arch with straight segments is sometimes called a Rigid F rame. 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.

9. EDGE SUPPORTED FOLDED PLATES: T he 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. T he slab between columns must be designed as a beam and it may be convenient to extend the main roof slab as a Cantilever C anopy. T he 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. N ote 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.

10. WALLS CONTINUOUS WITH SHELL: I n this structure the walls are of tilt-up concrete construction; concrete is cast flat on the floor and raised into place by cranes. T he walls are designed to be continuous with the roof plates. Tilt-up walls usually are joined by poured-in-place columns. in this design, columns are not necessary at the junction of the individual side wall panels because the walls are braced at the top. O nly a simple grouted key slot is provided. The tilt-up panels can serve as their own foundation walls so only a continuous footing pad is used with a notch to receive the tilt-up panel. D ock height interior floors can be constructed by filling the interior of the building up with dirt to the required height. T he tilt-up walls can be designed for this lateral load because they are held at the top by the shell and act as vertical beams rather than as Cantilever R etaining.

11. THREE SEGMENT FOLDED PLATE: T he end stiffeners are rigid frames rather than deep Girders as in the last example. T he 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. T he 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. T he dimensions of the plates are dependent on both the width of the barrel and on the span. T he 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. F or example, assume for the above structure that the span is 60 feet and the bay width is 24 feet. the depth of the shell should be about 6 feet and the horizontal width of each plate with a three segment plate should be about 8 feet. 6 the slope of the plates is 6/8, which is about 37 degrees and is satisfactory. the thickness of the plates could be about 3 ½ inches.

12. THE APPLICATION OF FOLDED STRUCTURES As Roof Structure As Wall Structure As Steel Sheet Piles As Floor Structure Miami Marine Stadium, Florida Church of Notre Dame de Royan , France Mezzanine ceiling called " Kielsteg " Securing The Foundation Pit With Larsen Planks

13. ADVANTAGES AND DISADVANTAGES OF FOLDED-PLATE STRUCTURE Advantages: Very light form of construction. To span 30 m shell thickness required is 60 mm only. The use of concrete as a building material reduces both materials cost and a construction cost. Longer span can be provided. Flat shapes by choosing certain arched shapes. Aesthetically it looks good over other forms of construction. Disadvantages: Shuttering is difficult . Greater accuracy in formwork is required. Good labor and supervision necessary . Rise of roof may be a disadvantage.

14. CASE STUDY: AIR FORCE ACADEMY CHAPEL, USA: The  United States Air Force Academy Cadet Chapel , completed in 1962, is the distinguishing feature of the Cadet Area at the United States Air force academy north of Colorado Springs .  It was designed by Walter Netsch of Skidmore, Owings and Merrill of Chicago. Construction was accomplished by Robert E. McKee, Inc., of Santa Fe, New Mexico. Originally controversial in its design, the Cadet Chapel has become a classic and highly regarded example of modernist architecture. The Cadet Chapel was awarded the American Institute of Architects National Twenty-five Year Award in 1996 and, as part of the Cadet Area, was named a U.S. National Historic Landmark in 2004. Architecture Construction: The most striking aspect of the Chapel is its row of seventeen spires. The original design called for twenty-one spires, but this number was reduced due to budget issues. The structure is a tubular steel frame of 100 identical tetrahedrons, each 75 feet (23 m) long, weighing five tons, and enclosed with A luminium panels. Architect : Walter Netsch , Length: 280 ft , Height: 150 ft , Width: 84 ft , Year: 1962

15. The tetrahedrons are spaced a foot apart, creating gaps in the framework that are filled with 1-inch-thick (25 mm) coloured glass. The tetrahedrons comprising the spires are filled by triangular Aluminium panels, while the tetrahedrons between the spires are filled with a mosaic of Coloured glass in Aluminium frame. The Cadet Chapel itself is 150 feet (46 m) high, 280 feet (85 m) long, and 84 feet (26 m) wide. The front façade, on the south, has a wide granite stairway with steel railings capped by Aluminium handrails leading up one story to a landing.  At the landing is a band of gold anodized Aluminium doors, and gold anodized aluminium sheets apparently covering original windows.

16. CASE STUDY: YOKOHAMA PORT TERMINAL Architect : Foreign Office Architects Floor Area: 34,732 m 2 , Length: 430m, Height: 15m, Width: 70m INTRODUCTION The steel frame structure was designed with the beautiful scenery of the port in mind. It is a three level facility of a gentle curved form. The occupable roof curves back in to form the ceiling of the level below and then again to form the floor. The inside space is barrier free without columns or beams and the vertical circulation is accomplished through ramps and elevators. SITE AND GENERAL The major pier possesses the ability to harbour vessels of varying sizing including the largest passenger ships. The port has both pedestrian and vehicular connection to the mainland . FUNCTIONS – Basement- machinery rooms First floor- parking Second floor- passenger terminal, multi-purpose space Roof- roof plaza, visitor’s deck

17. The terminal is a shed building measuring 412 meters in length and composed of 27 steel trusses averaging 42.5 meters in span and placed at 16 meter intervals . The trusses are joined longitudinally by trussed members of conventional configuration, and purlins carrying, either metal cladding or glazing. The trusses are carried on concrete piers extending from the basement parking level through the surface of the main level. The large shed employs a unified form though repetitive structural units to enclose a single homogeneous space. The transformation yields a complex of spaces that smoothly incorporates the multiple terminal, civic and garden programmes within and below its span.

18. FOLDED PLATE HUT-JAPAN:

19. There are many homeless people. Specially during disaster, many people become homeless. We can use the concept of folded plate structure to make portable shelter for the homeless people. Significant works on this project is already in progress. It is very cheap and easily useable by anyone. Recover Accordion Shelter Light Weight Emergency Shelter RECOMMENDATION

20. THANK YOU!...