The document discusses cable structure systems used in architectural design. It defines a cable structure as a form-active structure system that uses tension to support loads through non-rigid, flexible materials shaped into a certain configuration. The key components of cable structure systems are described, including the cable materials (PTFE-coated fiberglass fabric, steel, rubber), construction method of attaching cables to anchor points, and issues of dynamic wind effects that require strategies like adding guy cables. Advantages are highlighted such as lightweight construction, large spans, design freedom, and cost efficiency, while disadvantages include potential issues with maintenance and vulnerability to damage.

1. THE NATIONAL RIBAT UNIVERSITY
Eng. Mazin Elsayed A. Mustafa
Teaching Assistant
Faculty of Architecture
“THE CABLES STRUCURE SYSTEMS”

2. CONTENTS :
1. What’s structure
2. Architectural Structure
3. The Cable System
4. Construction Method
5. Cables System Materials
6. Dynamic effects of wind on typical flexible roof structure
7. Advantages & Disadvantages

3. What’s structure
❖ Structure is the performance of pattern! .
❖ The structure could be for everything life, system of
being.
❖ Social, economical, musical, biological, and
chemical.
❖ Relationship between the matter and the space.

4. • Architectural structure: a structure is a body or assemblage of bodies in space to form a system
capable of supporting loads.
• It’s a system or sub-system, means holding the components of a certain system and transfer the load
through the members of a structure to provide stability and durability.
• Most systems share Common Characteristics, including:
1.Systems have structure.
2.Systems have behavior, which involves inputs, processing and outputs of material, energy, information,
or data.
3.Systems have interconnectivity: the various parts of a system have functional as well as structural
relationships to each other.
4.Systems may have some functions or groups of functions
Architectural structure

5. THE CABLE SYSTEM
 MAJOR SYSTEM
 Form active structure systems
 Non rigid, flexible matter shaped in a certain way and secured by fixed
ends, support itself & span space. The transmit loads only through
simple normal stresses, either tension or through compression.
 Two cables with different points of suspension tied together form a
suspension system. A cable subject to external loads will deform in a
way depending upon the magnitude and location of the external
forces. The form acquired by the cable is called the FUNICULAR
SHAPE of the cable.

6. Form Active Structure Systems redirect external forces by
simple normal stresses : the arch by compression, the suspension
cable by tension. The bearing mechanism of form active systems
vests essentially on the material form.

7.  The natural stress line of the form active tension system in the
funicular tension line.
 Any change of loading or support conditions changes the form of
the funicular curve.

8. How it is built :
• The entire roof structure was made up of Thin Shell Structure “Membrane Structure”.
• Its members are united as 1 homogeneous entity to form the structure and spaces.
• The membrane is made up of fabric structure and other tensile structure.
• This kind of construction is also consider as a light weight construction.
• Considering the surface is a thin and flexible membrane, it has the ability to resist a
certain load through the tensile stress from the fabric itself without it being
compression or bending.
• It is the largest in the world with a diameter of 320m (1050 ft.).
Construction Method :
• The entire fabric is being supported by 72 tensioned steel stringer cables paring with 32mm diameter steel
spiral strand each for providing tension.
• The fabric material uses PTFE (poly tetra fluoric ethylene) - coated fiberglass.
• The stringers are supported at a radial spacing between 25m and 30m by an arrangement of upper
hanger and lower tie-down cables set out around the 12 100m high primary steelwork masts.
• The stringers on their radial lines are being kept in place by the circumferential cables.
• The force from the primary cables produce by rain, snow, wind etc from nature, everything is
• being collected from the center by a 30m diameter cable ring.
• This was built with 1248mm diameter cables to provide safety against failure or error of cable breakage.
At the perimeter, the radial cable forces are collected by 12 curved boundary cables and taken to 24
anchorage points.

9. Cables System Materials :
❖ PTFE (poly tetra fluoric ethylene) : coated glass fiber fabric PTFE coated glass fiber fabric is a dynamic
tensile material unmatched for its aesthetics and durability making it ideal for large scale roof and
tensile membrane structures.
• It has the properties of high durability and flame resistance.
• Usually, this kind of glass fibers are not affected by UV light but they are easily damaged by the water.
• The PTFE itself is completely inert and not affected by the weather.
• In all words, PTFE coated glass fiber has a longer life span and avoids the problem of dirt retention and
discoloration. This is why it always stay looking clean.
❖ Reinforced concrete :
• Reinforced concrete is a composite material which are count erected by the inclusion of reinforcement,
having high compressive and tensile strength.
• In fact, there are 24 spots of reinforced concrete, standing on top of the ground and are attached to
main cables of the building. It has been used as an anchorage points to support the whole structure.
• Concrete, if unreinforced, is notorious for cracking easily at any sourced of stress.
• It will cracks at all thickenings, ends of embedded steel and even down the middle of aisles.
• Hence, it has to undergo several retrofitting, like reinforcing the concrete by adding steel rods to the
concrete mixture, allowing concrete to set solid.
• The steel rods ensures that reinforced concrete can withstand tensile forces and hence, it become a
versatile and composite material.

10. Rubber :
• The aim of using rubber for this building is to achieve a maximum of weight saving in individual
components and parts.
• Rubber offer a considerable potential due to its low density and flexibility compared with metal
counterparts.
• At the bottom of each 12 masts, there is a rubber pot bearing with a single locating bolt.
• The bearing allows slight rotation of the mast at the connection point with the pyramid.
• Usage of rubber at the pot bearing helps to improve resistance to surface cracking due to higher binder
of contents.
• At the same time, it also helps in improving the aging and oxidation resistance of surface construction .
Steel :
• Steel is used mainly for its roof construction.
• Arranged radially over the fabric surface area the 72 tensioned steel stringer cables in pairs of 32mm
diameter steel spiral strand.
• The stringers are supported at a radial spacing between 25m and 30m by an arrangement of upper
hanger and lower tie-down cables set out around the twelve 100m high primary steelwork masts.
• All these masts, jut out from the fabric ceiling, representing the months of the year and the hours on a
clock face.

12. DYNAMIC EFFECTS OF WIND ON TYPICAL FLEXIBLE ROOF STRUCTURE :
• A critical problem in the design of any cable roof structure is the dynamic effect of wind, which
causes an undesirable fluttering of the roof.
• There are only several fundamental ways to combat flutter:
1. One is to simply increase the deal load on the roof.
2. Another is to provide anchoring guy cables at periodic points to tie the structure to the ground.
3. To use some sort of crossed cable on double-cable system.

13. Advantage
Advantages of the design structure:
- Extremely light weight
- Large span (size)
- Minimum amount of structure
- An open and unobstructed interior
- The low weight of the materials makes construction easier and cheaper than standard design
Cost efficiency:
Depending on the requirement, the shaped fabric under tension is able to reduce the cost of
construction by increase its spanned area under tension. In addition, the membrane provides both
structure and roofing shell.
Design Freedom:
With the flexible and highly formable systems provided from the tensile fabric membrane, this provide
the architect to go all out by using conventional construction materials. It also improve its functionality
by providing a well-designed tensile structure which adds aesthetics to the building.
Noise pollution:
The fabric curved construction method is able to diffuses both internal and external sound and whilst
absorbing at the same time.

14. Lower energy costs:
• The fabric have high sun reflecting properties and low absorbency of sunlight.
• Translucent materials provide a comfortable and natural light source by removing all artificial lighting
during the daytime.
• This greatly reduces the solar energy and heat that enters the structure.
• The woven base cloth combined with the appropriate coating allows a light transmission value of
around 10%.
• This provides a very comfortable level of illumination compared to the full brightness of outside.
Semi-permanent nature:
• Tension membrane structures ‘historically’ have been closely tied to major events such as exhibitions,
where shelters are needed for short periods of time.
• Tension Fabric structures can be easily designed for rapid relocation and re-erection; making them
perfect for high impact event structures.
• Not only does this help with practicality it also helps with planning permission for fixed term structures as
they are classed by most authorities as semi- permanent structures.

15. Disadvantages
• Poor performance ( Thermal & Acoustic )
• Exterior moisture and dehumidifier and address condensation
• Difficult making meaningful connections
• Easy to be damaged :
Fabric structures, if properly engineered and installed are virtually immune to damage and weather properties. Providing that
they are not likely to be vandalize or damage, they provide a reassuringly simple and durable solution.
• Difficulty of Maintenance :
Dirt can be clearly seen glass or polycarbonate, however the light diffusing properties of the fabric mean that the surface dirt is
not easily identified.