The aim of this power point presentation is to give an overview of significance of the cables in cable net structures. It accounts the type of cable net structures, structure of the cables and their applications. The fixing of cables to membrane or cable to ground plays a significant role in keeping a structure in equilibrium. This paper considers the various fixing elements for the junction of these structural members and the termination of the cables. It talks about general problems dealt with by cables net structures. It describes the various possibilities of anchoring the cable structures to ground. This paper takes a general preview of an application of cables in Lightweight membrane structures right from its design to installation.

1. ‘CABLES’ IN LIGHTWEIGHT
AND
MEMBRANE STRUCTURE
AR.SUVARNA LELE
ER.SHIREESH PATIL
CHAUGULE PATIL CONSULTANTS
PVT. LTD
Guimarães, Portugal – 21-23 July 2010

2. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
‘CABLES’
IN LIGHT WEIGHT MEMBRANE
STRUCTURES

3. MEMBRANE’S IN LIGT WEIGHT AND ME
STRUCTURES
AR SUVARNA LELE.ER -SHIRISH PATIL
Introduction
This paper takes a general preview of an application of cables in Lightweight
membrane structures right from its design to installation.
The paper accounts for the types of cable net structures, structure of the
cables and their applications.
This paper considers the various fixing elements at the junctions of the
structural members of cable membrane construction and the termination of
the cables.
It talks about general problems dealt with by cables membrane structures.
It describes the various possibilities of anchoring the cable structures to
ground.

4. In physics, tension is the magnitude of the pulling force exerted
by a string, cable, chain, or similar object. It is the opposite of
compression. As tension is a force, it is measured in Newton's
Tensile strength (σUTS or SU ) is indicated by the maxima of
a stress-strain curve and, in general, indicates when necking
will occur.

5. DESIGN OF TENSILE STRUCTURE AND TENSILE STRENGTH
Tensile strength, along with elastic modulus and corrosion resistance, is an
important parameter of engineering materials used in structures and
mechanical devices.
Tensile Strength is an intensive property, its value does not depend on
the size of the test specimen. It is, however, dependent on the
preparation of the specimen and the temperature of the test environment
and material.

6. MEMBRANE’S IN LIGHT WEIGHT AND
MEMBRANE’S IN LIGT WEIGHT
AND MEMBRANE STRUCTURES
MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Structural Principle:
Air pressure is used to support and force in all directions. This force is used to
support the fabric. The cables do not support the fabric, but hold it down. The
fabric is attached to the cables in panels resulting in a hybrid membrane. The
hybrid membrane transfers the stresses from the fabric to the cables. The cables
are attached to a compression ring, which resists the uplifting forces.
Types:
The two basic types of air supported structures are HIGH PROFILE and LOW.
PROFILE refers to the height to the structure relative to its span. High profile
structures are typically used for temporary or storage facilities and are often
free standing, which means they have no foundation upon which they rest. Low
profile structures are used to span long distances such as sports stadiums, also
low profile structures tend to be placed upon a building rather then the ground
itself, thus being used as roofs. This is due to the forces involved in supported the
structure.

7. MEMBRANE’S IN LIGT WEIGHT AND
MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
ORIGINAL TENSILE STRUCTURES-TENTS

8. SIMPLE MATHEMATICS OF CABLES
a)Beam b)Cable
Displacements Of Beam And Cable Structures.
One of the main characteristics of cable-membrane structures that they have no
stiffness against loading perpendicular to the line of the cable or the surface of the
membrane. The large displacements result in a significant change of the geometry
and therefore lead to a geometrically non-linear design and analysis procedure.
The stiffness of a cable-membrane structure can be increased in two ways: using
special geometry (for example increasing the sagging height) or using prestressing.
Furthermore the structural behaviour of cable-membrane structures can be
characterized by the following equation:
T1/R1+T2/R2=F
T1 and T2…..Internal forces in membrane.
R1 and R2 ….Radii of principal Curvature
F=External load

9. MEMBRANE’S IN LIGT WEIGHT AND
MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Russian engineer Vladimir Shukhov was one of the first to develop
practical calculations of stresses and deformations of tensile structures,
shells and membranes.
Structures exhibition pavilions for the
Nizhny Novgorod Fair of 1896, covering
the area of 27,000 mts2.

10. MEMBRANE’S IN LIGT WEIGHT AND
MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
TYPES OF TENSILE STRUCTURES
Cable net structures are for covering large unsupported spans. Cables are used as
support members to the covered membrane and usually fixed to the ground by
anchoring. The type and size of cables would depend upon the load conditions.
Cable supported Structures: Cable stayed structures
Here the tensile loads are transferred into Cables stabilize compression members
adjoining structures. They generate large (ex. typical light weight canopy with
lateral loads and may require additional masts and cable tie backs) and serve
reinforcement in existing structure .Steel only as tension members. Cables may
cablesare effective members of the roof only be used to suspend the
structure itself,the cables themselves resist structure,which would tranmit the
the various external loads. tensile forces to appropriate anchorages

11. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
CABLE-NET CONSRTUCTIONS
1.The constructional elements are steel pylons, steel cable networks, steel or
wooden grids, and roof coverings of acrylic glass or translucent, plastic-reinforced
sheeting.
2.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.
3.Cable net structures are for covering large unsupported spans with considerable
ease.

12. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
SOME TECHNICAL DEFINATIONS
Boss Plate – Doughnut-shaped plate attached to a cable ear plate to reinforce the
pinhole and allow a thinner plate.
Cable Cuff – Edge treatment in which the fabric is folded over on itself to form a
pocket in which a catenary cable can be installed.
Cable Fitting – Device attached to the end of a cable to allow a connection to another
member. Fittings can be swaged, speltered or compression type.
Guy Cable - This steel cable is used to support the structural integrity of the steel
frame. It may be attached at the ends of the steel struts (or “arms”) to hold them
together and resist them from movement relative to each other. Unlike catenary
cables, the lengths are calculated by a straight point-to-point dimension. The engineer
will need to determine the thickness by calculating the maximum stress on the cable.
Rebar Cage – A reinforcing matrix of steel rods used to strengthen concrete.
Swage – Type of cable fitting in which a sleeve fits over the outside of the cable and
the sleeve is compressed around the cable to form a tight fit.
Weldment – Connection component, usually steel, for the attachment of cables
and/or fabric. If may be free-floating or connected to other membranes.
Wire Rope Clip – U-shaped bolt with a special insert, specifically designed to clamp
a wire rope to itself when forming a loop end for temporary cables.

13. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
SOME TECHNICAL DEFINATIONS
Catenary – The curve theoretically formed by a perfectly flexible, uniformly dense,
inextensible “cable” suspended from each of two end points. In fabric structures
experience, this shape is probably not ever truly developed, but is commonly used to
describe the shape developed at the boundary of a uniformly stressed fabric structure
attached to a cable which is restrained only at its end points.
Catenary Cable - Steel cables that run through the pockets on the perimeter of a
tension structure fabric. The shape of the cable follows that of the pocket, which is
typically curved with a ratio of 1:10. The length of the cable is to be determined from by
the engineer supplying the fabric patterning. The thickness of the cable is to be
determined by the engineer who is calculating the reaction loads at the cable ends.
Catenary Edge – Method of securing the edge of a panel with a cable tensioned
between two fixed points.
Catenary Pocket (AKA “Banana Pocket”) - This is the pocket that is placed at the
perimeter of the fabric cover to secure the catenary cable. The pocket has a curve with
a ratio that is defined by the fabric patterning, but is typically close to a 1:10 ratio. This
means for every 10 feet of length, there will be about a foot of bend to it. Due to the
curvature of the shape, the pocket is typically fabricated by sealing together two halves
of the pocket together with an overlap of 1” to 2” at the outside edge of the pocket.

14. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
One of the main characteristics of cable-membrane structures that they have no
stiffness against loading perpendicular to the line of the cable or the surface of the
membrane.
Displacements of beam and cable structures.
Concentrated loads Selfweight-catenary Uniformly distributed Asymmetric loading
(polygonal form) form vertical loads with Uplift
Single cable structures with different loading conditions

15. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
PRESTRESS-The stresses in cable net can be created by using
1) compression ring beams
2) by encasing in concrete.
3) by spanning over the edge cables.
Spanning a ring beam Spanning on to edge cables supporting heavy cladding
Vertical support Inclined supports Suspension bridge Combination of cable
for cables for cable type structure truss and girder into
one cable beam
TYPES OF SUPPORTS FOR CABLES

16. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
The Principal methods of providing stability are the following:
Additional Staying
Prestrssing By Cable With opposite Curvature
Staying With Transverse Cables To Ground Or
To Another Part Of The Structure
Cable stability: Plane systems

17. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Cable Stability:Cable Trusses Cable stability:Conical Membrane

18. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Complex tent system with internal supports
Anticlastic cable nets with boundary arches

19. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Solutions for Anchoring cable stayed CANTILEVER COLUMNS
structures:
a] Stayed columns are used with ground
anchors to deal with vertical and
horizontal reactions provided by axially Suspension cable
loaded columns.
Restraining cable
b] Cantilever columns or legged column. 3.Mast and strut
c] Provision of rigid diaphragms to
support vertical columns acting with GUYED MASTS
horizontally loaded edge beams. Anchor
Vertical and horizontal reactions are
provided by axially loaded elements such LEGGED COLUMNS
as stayed columns used with ground
anchors. 1.Suspension cable 2.Horizontal beam
3.Rigid diaphragm
d]Vertical cylindrically curved walls.
e] A self relating equilibrium by form
related boundary shapes where no
tensions around anchors are required

20. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Some tension anchorage possibilities
are illustrated below
Form related boundary shapes Massive foundation and
Soil loading
Combination of stiffened plates
counterfort walls and soil loading
Vertical tension pile with Tension pile collinear
Cylindrical walls Horizontal reaction component with restraining cable

21. Flowchart
Illustrating
General Approach
to Tensile
Membrane
Structure Design
and Engineering

22. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
EXAMPLE OF A STUDY MODEL- showing flower arrangement wire for
cables and main support structure. A thicker wire is used for the main
connection in the front of the section and hot glue for the connection places.
As for the material used to cover the section a stretchable mesh fabric is
used and for the base instalation foam is used. All of these materials worked
well for beginning stages, but for the next study model the experimenters
decided to use stronger materials and a sturdier base.

23. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
A TYPICAL 3D finite element program suite developed by Tensys for the design of
tensile structures. Featuring full,large deformation, geometric non-linearity, it is
based upon a Dynamic Relaxation solution process.
In TENS features modules for:
• Form Finding, with specified stress control of shape
• Load Analysis
• Membrane Patterning
• Geometric Post-processing
The program element library include
• Cable elements
• Slip Cables, modeling a sequence of cable elements in a friction-free pocket
• Membrane elements
• Beam elements

24. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Boundary conditions and analysis constraints include
• On-off contact constraints, including vector trajectories
and spherical surfaces
• Imposition of geodesic seam trajectories
• Closed gas/liquid cells, with the option of constant pressure, volume or
mass
Applied loading options include
• Wind snow fluid and gas loading updated according to surface
deformation
• Discrete applied loads and specified node displacements
and element forces

25. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Architecture of cables:
Steel cables are either spiral strand, where circular rods are twisted
together and "glued" using a polymer, or “locked coil strand”, where
individual interlocking steel strands form the cable (often with a spiral
strand core).
Spiral strand is slightly weaker than locked coil strand.Steel spiral strand
cables have a Young's modulus, E of 150±10 kN/mm² (or 150±10 GPa) and
come in sizes from 3 to 90 mm diameter. Spiral strand suffers from
construction stretch, where the strands compact when the cable is
loaded. This is normally removed by pre-stretching the cable and cycling the
load up and down to 45% of the ultimate tensile load.
Locked coil strand typically has a Young's Modulus of 160±10 kN/mm² and
comes in sizes from 20 mm to 160 mm diameter.
Rope is an assembly of multiple strands.
STRAND Z LOCK ROPE

26. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Architecture of cables:
1.The tension members are termed as cables are group of wires, strands or ropes.
2. A wire is continuous length of steel that has circular cross section. The word strand
indicates a group of wires surrounded around a single core in a twisted form. The layers
might be more than one. Z-lock cables are used in some structures which consist of z-
shaped wires at the perimeter of the strands.
One strand open cables- One strand close cable
a)1+6, b)1+6+12, a)1+6+z,b)1+6+12+z,
c)1+6+12+18,d)1+6+12+18+24 c)1+16+12+18+z
d)1+6+12+18 +z

27. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Architecture of cables
Cables comprise number of wires. The cables do not loose
their strength in case of failure of one wire. Cables have yield
strength of approximately 240 ksi to 270 ksi.
The wires in strand are zinc coated and stranded into helix
which forms a regular cross section. The core of strand
consists of central wire and other wires are wound around the
control wire in number of layers up to 4
Variety of cables with infill of zinc rich powder filling the gaps between the
wires
The several conditions which might affect the life expectancy of the cables are type of
material, its properties, climate conditions, coating systems and high performance
paints.

28. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Erection on site: The
cable nets are completely
assembled on the ground,
then lifted to their final
positions.

29. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Constructional Details
Bale ring/membrane plate Tensioner cables and pin connection to a plate
Anchoring frame to base plate Edge Detail-Fixing at boundary

30. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Joining of cable to foundation through steel saddle ,hinges ,trusses.
membrane ,cable junction Tensioner Cable junction to Membrane and
to support support cable junction at
the edge

31. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
AR.SUVARNA LELE ER.SHIRISH PATIL
Junction at cable to boundary
1)Grommet 2)swaged terminal 3)and 4)pin Cast in socket terminal
Termination of Cables

32. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Open Spiral Strand Cable Steel Cable
Connectors
Clamps Compression Strut Galvanised cables Various Cables

33. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Cylindrical Connectors Fork connector Full locked cable
Fork Connector
Cable For Tensile Strength
Cable For Retraceable Tensile Strength Compression struts

34. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL

35. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Components and Details Hardware
Stainless steel, Galvanized or Custom finishes

36. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Specialised Hardware
Cable Clamps

37. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Pick the right components
Samuel J. Armijos, AIA, www.fabricarchitect.com

38. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Components and Details (cont.)
Hardware,Stainless steel, Galvanized or Custom finishes
Hooks,plates,hangers,nets

39. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL

40. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
A CASE STUDY
A Pavillion At Warsaw-
The steel structure
received the
ECCS Steel Design Award
in 1997.

41. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
The steel structure is composed by-
1. transversal frames.
2. longitudinal stiffening systems
3. intermediary tension frames,
Makowski, Z.S. (1995):

42. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
Details At The Junctions Sectional Elevation
The roof is composed by the middle tension membranes in the form of
saddle hypars supported on steel arches and end membrane, supported
on end steel arch and tensioned inclined end columns.

43. MEMBRANE’S IN LIGHT WEIGHT
AND MEMBRANE STRUCTURES
AR.SUVARNA LELE ER.SHIRISH PATIL
REFERENCE:
1.Makowski, Z.S. (1995): Light-weight structures.
2.Gopal Mishra http://theconstructor.org/2009/10/cable-and-tension-structures
3.Ambroziak. A, Klosowski. P .2006.On constructional solutions for
tensile Structures (17-20 ) .
4.Armijos.S, www.fabricarchitect.com (images-20-24)
5.Huntington C. 2004.The tensioned fabric roof . (12-14)
6.Kloiber L,P.E,.Eckmann D, AIA,S.E,P.E,.Meyer.T, Hautzinger .S,2004.
Design consideration in cable stayed roof structure. AI conference,
North American steel construction March 2004, Model steel construction .
7.www.membranes24.com
8.www.architen.com
9.www.taiyomc.com
10.www.tensileworld.com
11.www.FabricArchitect.com

44. THANK YOU
Architect-Suvarna Lele.
Engineer-Shirish Patil.
CHAUGULE PATIL CONSULTANTS P LTD