Relation Between Truss, Portal Frame and[1]

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RELATION BETWEEN TRUSS, PORTALFRAME

AND SPACE FRAME

Submitted byA. Raja sekhar


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Truss

In architecture, a truss is a structurecomprising one or more triangularunits constructed with straightmembers whose ends are connectedat joints referred to as nodes.

External forces and reactions tothose forces are considered to actonly at the nodes and result in forcesin the members which are either

tensile or compressive forces.


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A truss consists of straightmembers connected at joints,traditionally termed panel points.

Trusses are composed oftriangles because of thestructural stability of that shapeand design.


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6 - 4

• Most structures are made ofseveral trusses joined togetherto form a space frameork.!ach truss carries those loads

hich act in its plane and maybe treated as a to"dimensional structure.

• #hen forces tend to pull the

member apart, it is in tension.#hen the forces tend tocompress the member, it is incompression.


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$ " %

•

Members of a trss are s!e"#er a"#"ot $a%ab!e of s%%ort&"' !ar'e !atera!!oa#s( Loa#s mst be a%%!&e# at t)e *o&"ts(


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Types of trusses


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&rame A frame is a structural system that

supports other components of a physicalconstruction.

A framed structure in any material is onethat is made stable by a skeleton that isable to stand by itself as a rigid structureithout depending on 'oors or alls toresist deformation.


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&rames structures can bedi(erentiated into)

*. Rigid frame structures

A+ in ended,

-+ /ed ended.

0. -raced frame structures

A+ gabled frames,

b+ portal frames.


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ortal frames

ortal frames are fre1uentlyused over the entrance of abridge and as a main sti(ness

element in building design inorder to transfer hori2ontal forcesapplied at the top of the frame to

the foundation. 3n bridges, these frames resistthe forces caused by ind,earth uake and unbalanced


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ortals can be pin supported,/ed supported, or supported by

partial /ity.


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A typical frame is characterised by)

A span beteen *% and %5 m

An clear height 6from the top of the 'oor to theunderside of the haunch+ beteen % and *0 m

A roof pitch beteen %7 and *57 6$7 iscommonly adopted+

A frame spacing beteen $ and 8 m

9aunches in the rafters at the eaves and ape/

A sti(ness ratio beteen the column and raftersection of appro/imately *.%.


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P&t$)e# roof

s+mmetr&$%orta! frame

Porta! frame &t)&"ter"a! me..a"&"e /oor

Cra"e %orta! frame&t) $o!m" bra$0ets


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Ma"sar#%orta! frame

Mo"o-%&t$)%orta! frame

Ce!!!ar beam%orta! frame


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Space frames

A space frame is a structure systemassembled of linear elements soarranged that forces are transferred

in a t)ree-#&me"s&o"a! ma""er(:n some cases, the constituentelement may be to dimensional.

Macroscopically a space frame oftentakes the form of a /at or $r1e#srfa$e


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A space frame is a truss"like,lighteight rigid structureconstructed from interlocking struts

in a geometric pattern. Space framesusually utili2e a multidirectional span,and are often used to accomplish

long spans ith fe supports.


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A space frame is usuallyarranged in an array of single,double, or multiple layers ofintersecting members.

Some authors dene spaceframes only as double"layer grids.

A single"layer space frame that

has the form of a curved surfaceis termed as bra$e# 1a!t,bra$e# #ome, or !att&$e# s)e!!(


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S&"'!e, Dob!e a"# Tr&%!e La+ere#

Single layer frame has to be singlyor doubly curved.

;ommonly used space frames are

double layered and 'at. Triple layered is practically used for

a large span building.

COMPONENTS OF SPACE FRAME

;onsists of a/ial members ) #hich

are tbes and $o""e$tors


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!/amples of space frames


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Dierence between truss and frame

*. Trusses and frames are bothcomposed of triangularmembers connected at joints.


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*. :n a truss, the joints are pintype joints and the membersare free to rotate about the pin.As such, a truss cannot transfermoments and members aresubjected to only a/ial forces6tensile and compression+.

0. 3n the other hand, members offrames are connected rigidly at

joints by means of elding and

bolting. Therefore the joints of


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load transfer )

:n a truss the loadis transferred fromtop chord, bottomchord and eb tothe alls.

•:n this the loadis transferredfrom rafters to

the stanchions


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:n space frames the load is

transferred < dimensional manner. :nthis there ill be no support alls and'oor


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ma/imum clear span)

Trusses are used for spans of 2 m to32 m. and the span depends on thepitch of the roof and the depth of the

beam is s%a"53( :n portal frames that the ma/imum

span can reach 2m the columnspacing can be done to 34m( Thedepth of the beam s%a"6

:n space frames the clear span illbe around 5m and the depth iss a"4(


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All the three of them are used as roof

covers and the trusses and portal framesare used for bridges also.

hereas the space frames are used forairport hangers mainly.

The materials used in its construction are)For trsses e se t&mber, RCC a"#stee!7((

a"# for %orta! frames e se t&mber,RCC a"# stee!(

for s%a$e frames e se m&!# stee!a"# sta&"!ess stee!(


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Trusses and frames are bothcomposed of triangular membersconnected at joints.

TRUSS


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Thank u

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Relation Between Truss, Portal Frame and[1]

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