Cable Structure

Cable Structure:Principal means of support, because cable have high tensile strength but offer no resistance to compression of bending.

- Concentrated loads > straight line segment .

- Uniformly distributed load > inverted arch.

The funicular shape:It assumed by a freely deforming cable in direct response to the magnitude and location of external forces.

- A cable always adapts its shape so that it is in pure tension under the action of applied load.

Catenary:Parabola curve, flexible, suspended freely from two points not in the same vertical line.

Suspension Structure:Cable suspend and prestressed between compression members to directly support applied load.

Single-Curvature Structure: It's parallel series of cables to support surface-forming beams, reduced by increasing the dead load on the structure.

Double-Cable Structure: It's upper and lower setoff cables, pretensioned by ties or compression struts. It's more rigid and resistance to flutter.

Double-Curvature Structure:It's field of crossed cables, forming a self-damping system. It's more resistance to flutter.

Cable-Stayed Structure:It's vertical or inclined masts from which cable extend to support spanning members arranged in a parallel or radial pattern.

Albert Bridge, London

- Creator(s): Godden, William G.

- Location: EUROPE/England/London/United Kingdom.

- Albert Bridge across the River Thames is one of the earliest cable-stayed bridges, it opened in 1873.

J.S Dorton Arena Hotel, - By: Governor William.

- Location: Raleigh, North Carolina.

- Built in: 1952

- It's type: (Double-Curvature Structure).

- The building's dimensions: 92m*97m.

Striations:

Continuing with the striated/modular approach to design, this is a conceptual study for a lightweight sky bridge connecting two buildings above ground. This structure can also be a free standing formal pavilion. Each striation contains only single curvature.

Membrane Structures

What does the word membrane mean?Is a thin, film-like structure that separates two fluids. It acts as a selective barrier, allowing some particles or chemicals to pass through, but not others.

Membrane Structure:Membranes are thin, flexible surfaces that carry loads through the development of tensile stresses.

It suspended between posts or it can be supported by air pressure.

Membrane structures should have relatively sharp curvatures in opposite directions to avoid extremely high tensile forces.

Membrane elements:

Membrane and steel cable: Transmit external loads to masts and ground anchors by means of tensile forces.

The membrane may be tied to the must supports by a reinforcing cable loop or be stretched over a distribution cap.

Reinforcing edge cable: Stiffen the free edges of a tent structures.

The masts: Are designed to resist buckling under compressive loading.

Membrane shapes:

^ Rectangular examples.

>A complexexample with different curved sides.

>

A hexagonal shaped example, (a) medial axis of the domain, (b) medial axis with added holes at the center of triangular regions, (c) medial axis of one triangular region with a hole, (d) finite element mesh of one triangular region with a hole, (e) shape after form-finding without holes and (f) shape after form-finding with holes.

Where it can be used?Mostly everywhere that needs shading such as:

- Airports: “Translucent membrane”

- Stadiums:

- Parks: “To get shade while walking and enjoying the time”

-Shopping Centers: “It is used as an awning, umbrella, facade, pedestrian walkway, etc”.

- Resorts and Spas:

-Residential: “Can be used as outdoor family room, seasonal tent for a BBQ, party tent”

- Restaurants & Cafés:

Marassi Beach Resort, Egypt

It’s a fabric structure at the Marassi Beach Resort. Overlapping triangles and hypars. To provide shade to protect from harmful UV rays in place like Egypt.

Tent structures:It prestressed by externally applied forces and held completely taut under all anticipated load conditions.

Band shell:

It’s a large, outdoor performing venue typically used by bands and orchestras. The roof and the back of “the shell” protect musicians from the weather and reflect sound through the open side and out towards the audience.

Translucent membranes:

Provide natural illumination, gather solar radiation in the winter, and cool the interior spaces at night.

Serpentine Gallery, London

By: Zaha Hadid.

Temporary tensile fabric Installation consisting of 3 parasols for the Serpentine Gallery’s Summer Party located in Kensington Gardens.

Burnham Pavilion, Chicago

By: Zaha Hadids

The temporary pavilion, which can be dismantled and relocated, is a tent-like structure made of lightweight aluminum and dressed in a tensile fabric. The interior of the Burnham Pavilion will feature a screen that will show a film that tells the story of Chicago’s transformation by local architects.

Pneumatic structures:

Placed in tension and stabilized against wind and snow loads by the pressure of compassed air.

Made of:

Woven textile or glass-fiber fabric coated with a synthetic material such as silicone.

Architectural fabrics in common use today include:

- PTFE

- Silicone-coated fiberglass

- Woven PTFE

- PVC-coated polyester

- PVC-laminated polyester

- Theatrical draperies

- Stretch fabrics (spandex)

- High-density polyethylene (HDPE)

- ETFE

Its kinds:

- Air-supported structures:

Consist of a single membrane supported by an internal air pressure which higher than the normal atmospheric pressure.

Securely anchored and it sealed along the perimeter to prevent leaking.

Air locks are required at entrances to maintain the internal air pressure.

- Air-inflated structures:

Consist of double membrane structure; to bulge in the middle is restrained by a compression ring or by internal ties or diaphragms.

The air-inflated structures supported by pressurized air within inflated building elements which are shaped to carry loads in a traditional way.

References:

http://nisee.berkeley.edu/elibrary/Image/GoddenC54

http://www.makingthemodernworld.org.uk/learning_modules/maths/02.TU.03/?section=9

http://luciosantos.blogspot.com/2008/02/striations.html

http://armijos.wordpress.com/category/new-york/http://www.bestfromchina.com/featured_partners/membrane_structure/Membrane_Structure_Material.html

http://www.bestfromchina.com/featured_partners/membrane_structure/Membrane_Structure_for_Large_Stadium.html

http://www.sciencedirect.com/science/article/pii/S096599781200172X

http://www.worldarchitectnews.com/suvarnabhumi-airport-bangkok/http://www.sheerfill.com/news_detail.aspx?id=249700

https://sites.google.com/site/structuresvarietyae390/home/description-of-structure

http://www.dezeen.com/2007/07/12/lilas-by-zaha-hadid-architects/http://www.mymodernmet.com/profiles/blogs/modern-architecture-burnham