Tensile Final

Tensile Structures

Tanvi Choudhari Vrunda Pachchigar Namrata Vyas Digisha Sinvhal Devanshi Mehta

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Tensile structures are characterized by the prevalence of tension force in their structural systems and by limitation of compression forces to a few support members Thus these lightweight structures do not require the considerable amount of construction material to absorb the buckling and bending moments in compression members.

Tension

Compression













1.mast and cable supported membranes •simple saddle membrane with linear perimeter supports. supports.

•Ridge type membrane with linear internal and perimeter support.

•Arch type membrane with linear internal support. support.













Types of structure with significant tension members Linear structures Suspension bridges Cable-stayed beams or trusses Cable trusses Straight tensioned cables Three-dimensional structures Tensegrity structures Pre stressed membranes Pneumatically stressed membranes Cable and membrane structures













• There are many different doubly-curved doubly-curved forms, many of which have special mathematical properties. The most basic doubly curved form is the saddle shape, which can be a hyperbolic paraboloid













Tensioned fabric structures • •

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True tensile fabric structures are those in which every part of the fabric is in tension. tension . The fundamental rule for stability is that a tensioned fabric structure must curve equally in opposite directions, this gives the canopy stability. This stability. This is known as an anticlastic form and mathematically as a hyperbolic paraboloid. We put the fabric of a tensile structure under tension. We do not stretch the fabric into position. It is cut and bonded together to make its final shape

Pre-tension is the most efficient way of resisting live loads snow, wind etc. Design















Fabrics : 1.PVC (polyvinyl chloride) coated polyester polyester is the least expensive, design life of 15 to 20 years due to ultra violet attack 2. Silicon coated giass Silicon glass has higher tensile strength than polyester, but being glass it is brittle, subject to damage from repeated flexing. Not subject to ultra violet attack, 30+ year design life. 3. Teflon coated glass PVC coated













Advantages : • Unique building medium. • Lightweight and flexible, fabric interacts with and expresses natural forces. • Tensile fabric structures are an environmentally sensitive medium. medium . Tension is the most efficient way of using any material, material , it utilises the material at maximum efficiency rather than just the material at the extremes of the cross sectional form, as in bending and compression loads. loads. Fabric structures have higher strength/weight ratio than concrete or













Cables : • Cables can be of mild of mild steel, high strength steel , stainless steel or polyester or aramid fibres. fibres . • Structural cables are made of a series of small strands twisted or bound together to form a much larger cable













CABLE-NETS •Cable net structures are for covering large unsupported spans with considerable ease. • The constructional elements are steel pylons, steel cable networks, steel or wooden grids, and roof coverings of acrylic glass or translucent, plasticreinforced sheeting. •Cables are fastened into the edges of the steel network , and are laid over pin-jointed and usually obliquely positioned steel supports, and then anchored. Basic structure of the cable-net roof













OLYMPIC ROOF, Munich Construction materials used: Masts cable net membrane panels covered area

Construction

: steel : steel : acrylic : 74 000 m2















The connections used one bolt per joint, resulting in a freely rotatable node













Erection on site: The













oundations and masts













Roof covering Roof covering













Detail of how the acrylic plates are connected







































































































































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When the towers were completedCABLES,(MAIN & TEMPORARY) a temporary cable stretched between both and a wire mesh gangway built so that workers could start construction of the main cables. Workers and machinery pulled the main cables from one tower to the other. Once the main cables and the vertical cables were in position the deck / roadway was fixed hanging below them, them, 290 sections make up the entire bridge. cranes in operation and the deck as it was fixed in position, section by section.













DECK (ROAD)VIEW OF THE BRID IEW OF AKASHI KAIKYO FROM BELOW HE DECK BRIDGE













The London Eye • Designed by: architects David Marks, Julia Barfield, Malcolm Cook, Mark Sparrowhawk, Steven Chilton and Nic Bailey • Height 135 metres (443 ft) ,biggest Ferris wheel in Europe • most popular paid tourist attraction in the United Kingdom, visited by over 3 million people a year • Described by its operators as "the world's tallest cantilevered observation wheel" (because the entire structure is supported by an A-frame on one side only). allowing the wheel to hang over the River Thames. Thames.













LOCATION: London Eye is located at the western end of Jubilee Jubilee Gardens, Gardens , on the South Bank of the River Thames in London London,, United Kingdom, Kingdom, between Westminster Bridge and Hungerford Bridge. Bridge.













HOW LONDON EYE WORKS •

The rim of the Eye is supported by tie rods and resembles a huge spoked bicycle wheel.

The London Eye is an excellent example of a frame structure. Its steel design forms an "A" shape, with two large tapered legs at the base -- 20 meters apart and each over 58 meters in length. The legs lean toward the river at a 65-degree angle.

Cable backstays keep the frame from tilting into the river -they're anchored to the top of the frame and then buried in a concrete foundation 33 meters















COMPONENTS OF LONDON EYE IN DETAIL Capsules • The London eye has 32 capsules. Capsules have 360 degree views, a heating and cooling system and bench seating. se ating. It rotates at 26 cm (10 in) per second (about 0.9 km/h (0.5mph) so that one revolution re volution takes about 30 minutes. • Each capsule 24 people. • Instead of being suspended under the













1.Cables • six backstay cables holding the wheel in place The wheel part of the London Eye resembles a bicycle wheel -with a spindle and hub connected to the rim by 64 cables, or spokes.

16 additional rotation cables are attached to the hub at an opposing angle holding the rim tight to the central spindle. to ensure there's no lag between the turning of the rim and the turning of the hub.













1.Foundation • The main foundation for the London Eye is situated underneath the A-frame legs • it required 2,200 tonnes of concrete and 44 concrete piles - each of which is 33 metres deep • The second foundation, the tension foundation holding the backstay cables behind the wheel, used 1,200 tonnes of concrete.













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Spindle At the centre of the London Eye is the vast hub and spindle. The main elements were manufactured cast in steel. The spindle itself was too large to cast as a single piece so instead was produced in eight smaller sections. Two further castings, in the form of great rings form the main structural struc tural element of the hub. The hub has a rolled steel tube forming the spacer that holds them apart. All the casting was carried out by Skoda Steel.













CONSTRUCTION OF LONDON EYE















•Once the wheel was complete it was raised into an upright position by a strand jack system( hydraulic lifts and cables), being lifted at 2 degrees an hour until it reached 65 degrees.













MECHANISM OF THE LONDON EYE The London Eye rotates around the hub like a MOTORIZED bicycle wheel.

Tensile Final

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