pile cap reinforcement formwork what is a pile cap? A pile cap is a thick concrete mat that rests on on piles and is usually part of the foundation foundation of a building especially a multi-storey building. It helps to distribute the load from the pillars or piers to the piles.
Typical dimensions : 5m wide x 800mm thick Concrete used: Grade 40/20 Nominal concrete cover to re-bars : 75mm blinding layer for underside Minimum cover to re-bars for precast concrete covers on topside : 0mm Thickness of all precast concrete covers : !25mm
"he #ile ca#s were were casted by em#loying em#loying a #um# truck with hydraulic hydraulic boom #lacer to #um# fresh concrete from truckmixer down to ca# formwork at $ok %u &am 'oad le(el) Nominal concrete cover to re-bars : 50mm* with a 75mm blinding layer below the underside as well
+oncreting o#eration for the #ile ca#s was launched simultaneously using two di,erent methods: one by crane-and-ski# bucket and the other by hydraulic exca(ator* in order to achie(e faster #lacing rates) .%ormwork .%ormwork is the term used for the tem#orary timber* #lywood* metal or other material used to contain* su##ort and form wet concrete until it has gained sucient strength to be self-su##orting) self-su##orting) .%alsework .%alsework is the term used to describe the tem#orary system or systems of su##ort for formwork)
reference:
htt#://www)ask)com/1uestion/what-is-a-#ile-ca# htt#://ci(cal)media)hku)hk/1ueenmary/structures/trough/#ileca#/default)htm htt#://ci(cal)media)hku)hk/1ueenmary/structures/bridge/ca#/default)htm
manufactured steel trusses
lift slabs
reference:
htt#://www)ask)com/1uestion/what-is-a-#ile-ca# htt#://ci(cal)media)hku)hk/1ueenmary/structures/trough/#ileca#/default)htm htt#://ci(cal)media)hku)hk/1ueenmary/structures/bridge/ca#/default)htm
manufactured steel trusses
lift slabs
Lift slab construction is construction is a method of constructing concrete buildings by casting the floor or roof slab on top of the previous slab and then raising (jacking) the slab up with hydraulic jacks, jacks, so being cheaper and faster as not requiring boxing and supports for casting in situ. Johnstone all, all, a dormitory at !lemson "niversity, "niversity, !lemson !lemson,, #outh !arolina was !arolina was erected using this method in $%&'. #everal of the blocks have now been demolished, and campus legend says that that two other similar structures built elsewhere collapsed before completion.citation needed *he method was involved in the +-mbiance la/a collapse la/a collapse in 0ridgeport, !onnecticut during construction in $%12, and resulted in a major nationwide federal investigation into this construction technique in the "nited #tates, and a temporary moratorium of its u se in !onnecticut.$ - patent was issued to to *om #lick for #lick for this construction method, called the 34out/5#lick3 34out/5#lick3 method, in $%&&.
what is lift slab construction?
Ba s i c a l l y, the method entails casting floor and ro o f slabs on or at ground level and jacking them up into position. The traditional lift slab construction sequence is i l l u s t rated in Fi g u re 1. Flat plate floors are commonly used because the y are so well suited to stackcasting, req u i ring form w o rk at only the edges of the slab and at floor openings. ope nings. !pecial lifting collars or shearheads are provided inthe slabs at the columns. Bond breaking compounds areapplied between slabs to separate them. "fter the slabsh a ve cured long enough to reach a pre s c ribed stre n g t h ,p owe rful hyd raulic jacks mounted on top of the columnslift the slabs into their re s p e c t i ve positions. " consoleconnected to each h yd raulic jack synchro n i #es the number of turns of the check nuts to assure a ssure that the concre t eslab is being raised the same amount at all points.$ift slab can be used for heights up to about 1% 1 % stori e s. &conomical column spacing ranges from '' to ('feet. )olumns may be pipe, tubes or wide flange sections* concrete columns may be used in ( to +storybuildings not re q u i ring splices.The big advantage of erecting concrete buildings bu ildings using lift slab construction is elimination of most formw o rk, an especially important factor in areas where labor costs are high. )o n c rete floor construction at groundlevel is convenient and requires no shore s, scaffolds orc ra n e s. !labs can be cast and protected easily duri n gcold weather without epensive heating and enclosure sre q u i red for ord i n a ry construction. "nother advantage isreduced handling and hoisting of materials and suppliesthat can simply be placed on top of the slabs and lifted with them.Because lift slab uses concre t e, the technique offersgood fire resistance and good acoustic ra t i n g s. -ass designed into walls, floors and roofs helps to reduce theew developments inlift slab construction
6igure $. *he lift slab technique reduces costs for multistory buildings by eliminating most formwork. typical lifting sequence is illustrated above.
6igure 7. 8ecent changes in lift slab construction include supporting the hydraulic jack off the column by a welded plate. *he old approach used jacks mounted on top of the columns. !olumns can now be up to 9 stories tall without field splices.
6igure :. - lift slab system used extensively in +atin -merica involves casting concrete bearing walls flat in the stack along with the floor slabs. *he wall panels are hinged to the floor with plastic rope, allowing them to unfold automatically as the stack is raised into position.
reference: htt#://en)wiki#edia)org/wiki/&iftslabconstruction
htt#://www)concreteconstruction)net/images/3ew20e(elo#ments20in20&ift 206lab20+onstructiontcm45-487)#df htt#://books)google)com)#h/books id9b+7;y$b<+=#g9$"8=l#g9$"8=d19lift>slabs=source9bl=ots9ansl60iw? =sig9@&6A0(5x13$k"BlsAh02
steel space deck roof /hat is !teel 0eck There are a wide variety of steel deck products on the market today, basically divided into two categories2 roof deck and composite floor deck. !teel deck is a structural panel element that acts as the surface of a floor or roof. The deck is roll formed from structural quality sheet steel and is engineered to span over joist or purlins. 3ariations in the thickness, shape and depth of the deck can be utili#ed to meet a variety of loading conditions and spans. The deck can also be fastened to the supporting structure to enable it act as a diaphragm and provide lateral bracing for the structure.
Advantages of Steel Deck Versatility : 6teel deck #roducts are a(ailable from +66H %abricator member com#anies in a range of de#ths I8 to 7 mm* I!-!/2 to in)JJ and di,erent rib s#acing) 'oof deck can also be su##lied as acoustical deck with #erforations in the web elements to attenuate sound) 6teel deck #roducts are a(ailable in a (ariety of thickness to meet most structural re1uirements) "his extensi(e choice of o#tions makes steel deck a##licable to a wide range of #roKects and structural designs) High Strength to Weight Ratio : "he strength of steel is used with maximum eciency in the design and fabrication of steel deck* resulting in #roducts with a high strength-to-weight ratio) +onse1uently* deli(ery* erection and structural framing costs can be lower than other systems) Aesthetics: Blthough steel deck is #rimarily a structural com#onent* it is (isually attracti(e when left ex#osed to the interior of the building) ?ith the #ro#erly s#eciLed #reLnished coating* steel deck is easy to maintain* durable and aesthetically #leasing) All-Weather Construction : 6teel deck can be erected in most weather conditions* eliminating the costly delays that can occur with other ty#es of roof systems) Required Fire Resistance Ratings : C&+ and C& Lre resistance ratings are a(ailable for many standard roof and Moor assemblies incor#orating steel deck) Uniform Quality : "hrough engineering and continuously reLned #roduction techni1ues* +66H fabricators #roduce deck that conforms to ex#licit industry standards) Proen !ura"ility : 6teel deck has a successful ser(ice history of o(er 0 years* which is indicati(e of the #roducts durability) #conomy and Value: Aalue is determined by combining initial costs* life-cycle costs* and o(erall #erformance) 6teel deck assemblies are the best (alue in roof and Moor designs) "hey combine low cost with to# #erformance
SECTION 05 3 !3 " STEE# $OO% &EC'IN(
)*$T " (ENE$*#
1.1 !4--"56 ". Furnish all materials and labor necessary to complete metal decking installation per the )ontract 0ocuments. &dit list of related sections for project requirements. !ection numbers and titles are those recommended in )!7 -asterFormat* revise numbers and titles to reflect actual sections in 8roject -anual. B. 5elated 5equirements2 1. !ection 9( :' 1%2 $ightweight 7nsulating )oncrete. '. !ection 9: 19 992 !tructural -etal Framing. (. !ection 9: '9 992 -etal ;oist. +. !ection 9< '' 1%2 5oof Board 7nsulation. :. !ection 9< %9 992 Flashing and !heet -etal. %. !ection 9= =1 992 8ainting 1.' 5&F&5&)& !T"0"50! !T"0"50! F>5 ?4"$7T6 "!!45")& "!!45")& ". )odes@!tandardsA The work and materials of this section shall comply with2 1. "!)& <2 -inimum 0esign $oads for Building and >ther !tructures. '. !ection properties shall be derived in accordance with "7!7 orth "merican !pecification for the 0esign of )oldFormed !teel !tructural -embers, latest edition. (. -etal 0ecking is to be attached to the structural frame in conformance with "/! "/! 01.1 !tructural /elding /elding )ode A !teel and 01.( !tructural /elding /elding )ode A !heet !teel. +. 7)) 5esearch 5eport o. &!51+1+. :. 7"8-> 5esearch 5eport o. 7"8-> &!91%1
7nsert the appropriate $.". )ity 5esearch 5eport o. when applicable* '(>F 0&)I 8"&$! uide !pecification 9: (1 '( ' 1.( !4B-7TT"$! ". 8roduct 0ata for each type of decking specified, including dimensions of individual components, profiles, and finishes. B. !hop drawings2 8rior to fabrication, prepare shop drawings for work under this section and submit to "rchitect. !hop drawings are to include deck layout, deck type and gauge, framing and support of openings, dimensions and sections, details of accessories and type and location of welds. -anufacturerJs product literature and relevant approvals are to be submitted with the shop drawings. 1.+ 85>04)T 0&$73&56, !T>5"& "0 H"0$7 ". -etal 0eck2 Transport, store and erect metal deck and accessories in a mann er that will prevent corrosion, deformation or other damage. !tore deck clear of the ground with one end elevated to promote drainage* protect metal deck from water and the elements with a water resistant material. 7nclude the following when "custadekK is specified2
B. "custadek !ound "bsorption Batts2 !tore batts in an enclosed area, protected from the elements. )*$T ! " )$O&+CTS
'.1 -"T&57"$ "0 F77!H&! ". -etal roof deck to be "!) !teel 0eck Lselect appropriate profileEsG and gaugeEsGM. 1. B(% L''M, L'9M, L1CM, L1%M gauge*1 1@' inches deep by (% inches wide. '. ('K L''M, L'9M, L1CM, L1%M gauge* ( inches deep by (' inches wide. (. '+ L''M, L'9M, L1CM, L1%M gauge* ( inches deep by '+ inches wide. +. '/(% L''M, L'9M, L1CM, L1%M gauge* ' inches deep (% inches wide. :. (/(% L''M, L'9M, L1CM, L1%M gauge* ( inches deep by (% inches wide. %. BF(% L'9@'9M, L'9@1CM, L'9@1%M, L1C@'9M, L1C@1CM, L1C@1%M, L1%@1%M gauge* 1 1@' inches deep by (% inches wide. <. F'+ L'9@'9M, L'9@1CM, L'9@1%M, L1C@'9M, L1C@1CM, L1C@1%M, L1%@1%M gau ge* ( inches deep by '+ inches wide. 0eck units are to be fabricated from sheet steel conforming to "!T- "%:( "%:( !! rade +9 with a galvani#ed coating. '/(% '/(% and (/ ( /(% (% are available in '+N wide panels* when specified, the designations are '/'+ and (/'+. /hen specifying )8(', use the following, for )8(' 1C gauge* replace "!T- "%:( "%:( !! rade C9 with "!T- "%:( rade ((. <. )8(' L'%M, L'+M, L''M, L'9M, L1CM gauge* 1 (@C inches deep by (' inches wide. 0eck units are to be fabricated from sheet steel conforming to "!T- "%:( "%:( !! rade C9, with a +9 galvani#ed coating. /hen specifying 0eep 0eck and 0eep )ellular, using the following2 1. 0eep 0eck L'9M, L1CM, L1%M, L1+M gauge* + 1@', %, or < 1@' inches deep by 1'
inches wide. '. 0eep 0eck )ellular L'9@'9M, L'9@1CM, L'9@1%M, L1C@'9M, L1C@1CM, L1C@1%M, L1%@1%M gauge* + 1@', %, or < 1@' inches deep by '+ inches wide. 0eck units are to be fabricated from sheet steel confirming to "!T- "%:(, Fy O ((ksi with a galvani#ed coating. /hen specifying acoustical deck use the following2 "!) !teel 0eck, " 0ivision of "!) 8rofiles, 7nc. !T&&$ 5>>F 0&)I 8"&$! uide !pecification 9: (1 '( ( ". -etal roof deck to be "!) !teel 0eck Lselect appropriate profileEsG and gaugeEsG.M 1. B(% "custadek L''M, L'9M, L1CM, L1%M gauge, 1 1@' inches deep by (%inches wide. '. (' "custadek L''M, L'9M, L1CM, L1%M gauge, (inches deep by (' inches wide. (. '+ "custadek L''M, L'9M, L1CM, L1%M gauge, ( inches deep by '+ inches wide. +. BF(% "custadek L'9@'9M, L'9@1CM, L'9@1%M, L1C@'9M, L1C@1CM, L1C@1%M, L1%@1%M gauge* 1 1@' inches deep by (% inches wide. :. F'+ "custadek L'9@'9M, L'9@1CM, L'9@1%M, L1C@'9M, L1C@1CM, L1C@1%M, L1%@1%M gauge* ( inches deep by '+ inches wide. %. 0eep 0eck "custadek L'9M, L1CM, L1%M, L1+M gauge* + 1@', %, or < 1@' inches deep by 1' inches wide. <. 0eep 0eck )ellular "custadek L'9@'9M, L'9@1CM, L'9@1%M, L1C@'9M, L1C@1CM, L1C@1%M, L1%@1%M gauge* + 1@', %, or < 1@' inches deep by '+ inches wide. C. '/F(% "custadek L'9@'9M, L'9@1CM, L'9@1%M, L1C@'9M, L1C@1CM, L1C@1%M, L1%@1%M gauge* ' inches deep by (% inches wide. =. (/F(% "custadek L'9@'9M, L'9@1CM, L'9@1%M, L1C@'9M, L1C@1CM, L1C@1%M, L1%@1%M gauge* ( inches deep by (% inches wide. B. "custadek perforations are 1@CN or :@('N diameter holes on staggered cen ters. The noise
reduction )oefficient is to be Lselect from chart on pages '( and '+M. The 5) values were developed in accordance with "!7 )+'(, as performed by 5iverbank $aboratory. "!) !teel 0eck panels, in their standard sheet steel, contain approimately '+.( percent postconsumer recycled content and =.+ percent preconsumer recycled content, for a total '= percent recycled content as calculated for this $&&0 credit. Higher percentages are available if specified. B. L>r ). for acoustical deckM !ustainability )haracteristics2 1. 5ecycled )ontent2 L'=M L:9M L<:M percent postconsumer recycled content L, calculated according to $&&0 )redit -5+M. '. !hipping 0istance2 8rovide panels manufactured at the following factory2 7f locally manufactured materials are a project requirement, select factory closer to 8roject site. a. Fontana, )alifornia ='((: b. /est !acramento, )alifornia =:%=1 7f the project is subject to Federal Buy "merican provisions, which requires that panels be manufactured in the 4!" and that :9 percent of the cost of the panels be of 4.!.". origin, use the following2 ). L>r 0. for acoustical deckM -anufacturing )haracteristics2 8rovide panels complying with provisions of Buy "merican "ct +1 4.!. ) 19a A 19d. 7f the project is subject to Buy "merica "ct E!T""G or "merican 5ecovery P 5einvestment "ct E"55"G '99= Ewhich requires that steel used in the manufa cturing process be poured and melted in the 4!", use the following2 ). L>r 0. for acoustical deckM -anufacturing )haracteristics2 8rovide panels complying with provisions of the Buy "merica "ct E!T""G or the "merican 5ecovery P 5einvestment "ct E"55"G '99=. '.' F"B57)"T7>
". -etal 0eck -anufacture deck units to lengths as indicated on shop drawings. 8anel end conditions are to be butted or endlapped, 'N minimum. !idelaps are to be male@female interlocking type allowing connection with 0eltaripK tool. !idelaps are to be nestable or interlocking when using screwtype fasteners. /hen specifying )8(' delete the last two sentences and insert2 !idelaps are to be overlapping type. B. "ccessories Fabricate steel deck accessories Enot including cell closuresG from the same gauge and materials as adjacent steel deck. reference:
htt#://www)cssbi)ca/
space frames ;n architecture and structural engineering, a space frame or space structure is a truss5like, lightweight rigid structure constructed from interlocking struts in a geometric pattern. #pace frames can be used to span large areas with few interior supports. +ike the truss, a space frame is strong because of the inherent rigidity of the triangle< flexing loads (bending moments) are transmitted as tension and compression loads along the length of each strut.
;f a force is applied to the blue node, and the red bar is not present, the behaviour of the structure depends completely on the bending rigidity of the blue node. ;f the red bar is present, and the bending rigidity of the blue node is negligible compared to the contributing rigidity of the red bar, the system can be calculated using a rigidity mat rix, neglecting angular factors.
#implified space frame roof with the half5octahedron highlighted in blue
*he roof of this industrial building is supported by a space frame structure.
*,-anta.es of Space %rames
1. >ne of the most important advantages of a space structure is its lightweight. This is mainly due to
the fact that material is distributed spatially in such a way that the load transfer mechanism is primarily aial Q tension or compression. )onsequently, all material in any given element is utili#ed to its full etent. Furthermore, most space frames are now constructed with steel or aluminum, which decreases considerably their selfweight. This is especially important in the case of longspan roofs, which led to a number of notable eamples of applications. '. The units of space frames are usually mass produced in the factory so that they can take full advantage of the industriali#ed system of construction. !pace frames can be built from simple prefabricated units, which are often of standard si#e and shape. !uch units can be easily transported and rapidly assembled on site by semiskilled labor. )onsequently, space frames can be built at a lower cost. !econdary beam Beam Beam "rch EaG EbG 8urlin F745& '+.' 5oof framing for a )ircular 0ome. '++ Handbook of !tructural &ngineering )opyright '99: by )5) 8ress(. " space frame is usually sufRciently stiff in spite of its lightness. This is due to its threedimensional character and to the full participation of its constituent elements. &ngineers appreciate the inherent rigidity and great stiffness of space frames and their eceptional ability to resist unsymmetrical or heavy concentrated load. 8ossessing greater rigidity, the space frames allow also greater Seibility in layout and positioning of colu mns.
+. !pace frames possess a versatility of shape and form and can utili#e a standard module to generate various Sat space grids, latticed shell, or even freeform shapes. "rchitects appreciate the visual beauty and the impressive simplicity of lines in space frames. " trend is very noticeable in which the structural members are left eposed as a part of the architectural epression. 0esire for openness for both visual impact as well as the ability to accommodate variable space requirements always calls for space frames as the most favorable solution.
)reliminar/ )lannin. (ui,elines
7n the preliminary stage of planning a space frame to cover a speciRc building, a number of factors should be studied and evaluated before proceeding to structural analysis and design. These include not only structural adequacy and functional requirements but also the esthetic effect desired. 1. 7n its initial phase, structural design consists of choosing the general form of the building and the type of space frame appropriate to this form. !ince a space frame is assembled of straight, linear elements connected at nodes, the geometrical arrangement of the elements Q surface shape, number of layers, grid pattern, etc.Qneeds to be studied carefully in the light of various pertinent requirements. '. The geometry of the space frame is an important factor to be planned, which will inSuence both the bearing capacity and the weight of the structure. Themodulesi#e is developed from the overall building dimensions, while the depth of the grid Ein the case of doublelayerG, the si#e of cladding, and the position of the supports will also have a pronounced effect upon it. For curved surface, the
geometry is also related to the curvature, or more speciRcally to the rise of the span. " compromise between these various aspects usually has to be made to achieve a satisfactory solution. (. 7n a space frame, connecting joints play an important role, both functional and esthetic, which derives from their rationality during construction and after completion. !ince joints have a decisive effect on the strength and stiffness of the structure and compose around '9 to (9 of the total weight, joint design is critical to space frame economy and safety. These are quite a few proprietary systems that are used for space frame structures. They should be selected on the basis of quality, cost, and erection efRciency. 7n addition, customdesigned space frames have been developed, especially for longspan roofs. 5egardless of the type of space frame, the essence of any system is the jointing system. +. "t the preliminary stage of design, the choosing of the type of space frames has to be closely related with the constructional technology. The space frames do not have such a sequential order of erection for planar structures and require special consideration on the method of construction. 4sually, a complete falsework has to be provided so that the structure can be assembled in the high position. "lternatively, the structure can be assembled on the ground, and a certain technique can be adopted to lift the whole structure, or its major part, to the Rnal position. reference:
htt#://en)wiki#edia)org/wiki/6#aceframe htt#://img20)imageshack)us/img20/5880/ch24s#aceframestructure)#df
col, roll"forme, sections wel,e, to.ether Cold-formed steel (CFS) is the common term for products made by rolling or pressing thin gauges of sheet steel into goods. !old5formed steel goods are created by the working of sheet
steel using stamping, rolling, or presses to deform the sheet into a usable product. !old worked steel products are commonly used in all areas of manufacturing of durable goods like appliances or automobiles but the phrase cold form steel is most prevalently used to described construction materials. *he use of cold5formed steel construction materials has become more and more popular since its initial introduction of codified standards in $%'9. ;n the construction industry both structural and non5structural elements are created from thin gauges of sheet steel. *hese building materials encompass columns, beams, joists, studs, floor decking, built5up sections and other components. !old5formed steel construction materials differ from other steel construction materials known as hot5rolled steel (see structural steel). *he manufacturing of cold5formed steel products occurs at room temperature using rolling or pressing. *he strength of elements used for design is usually governed by buckling. *he construction practices are more similar to timber framing using screws to assemble stud frames.
!old5formed steel building
!old5formed steel members have been used in buildings, bridges, storage racks, grain bins, car bodies, railway coaches, highway products, transmission towers, transmission poles, drainage facilities, various types of equipment and others. $ *hese types of sections are cold5formed from steel sheet, strip, plate, or flat bar in roll forming machines, by press brake (machine press) or bending operations. *he material thicknesses for such thin5walled steel members usually range from =.=$'2 in. (=.:2: mm) to about > in. (9.:& mm). #teel plates and bars as thick as $ in. (7&.' mm) can also be cold5formed successfully into structural shapes (-;#;, 7==2b).
istory of cold5formed steel *he use of cold5formed steel members in building construction began in the $1&=s in both the "nited #tates and ?reat 0ritain. ;n the $%7=s and $%:=s, acceptance of cold5formed steel as a construction material was still limited because there was no adequate design standard and limited information on material use in building codes. @ne of the first documented uses of cold5 formed steel as a building material is the Airginia 0aptist ospital $, constructed around $%7& in +ynchburg, Airginia. *he walls were load bearing masonry, but the floor system was framed with double back5to5back cold5formed steel lipped channels. -ccording to !huck ?reene, .B of Colen 6risa -ssociates 7, the joists were adequate to carry the initial loads and spans, based
on current analysis techniques. ?reene engineered a recent renovation to the structure and said that for the most part, the joists are still performing well. - site observation during this renovation confirmed that 3these joists from the roaring twenties are still supporting loads, over 1= years laterD3 ;n the $%'=s, +ustron omes built and sold almost 7&== steel5framed homes, with the framing, finishes, cabinets and furniture made from cold5formed steel.
istory of -;#; design standards edit Eesign standards for hot5rolled steel (see structural steel) were adopted in $%:=s, but were not applicable to coldFformed sections because of their relatively thin steel walls which were susceptible to buckling. !old5formed steel members maintain a constant thickness around their cross5section, whereas hot5rolled shapes typically exhibit tapering or fillets. !old5formed steel allowed for shapes which differed greatly from the classical hot5rolled shapes. *he material was easily workable< it could be deformed into many possible shapes. Bven a small change in the geometry created significant changes in the strength characteristics of the section. ;t was necessary to establish some minimum requirements and laws to control the buckling and strength characteristics. -lso it was observed that the thin walls underwent local buckling under small loads in some sections and that these elements were then capable of carrying higher loads even after local buckling of the members. ;n the "nited #tates, the first edition of the #pecification for the Eesign of +ight ?age #teel #tructural Gembers was published by the -merican ;ron and #teel ;nstitute (-;#;) in $%'9 (-;#;, $%'9). : *he first -llowable #tress Eesign (-#E) #pecification was based on the research work sponsored by -;#; at !ornell "niversity under the direction of late rofessor ?eorge Hinter :since $%:%. ' -s a result of this work, ?eorge Hinter is now considered the grandfather of cold5formed steel design. *he -#E #pecification was subsequently revised in $%&9, $%9=, $%97, $%91, $%1=, and $%19 to reflect the technical developments and the results of continued research at !ornell and other universities (4u et al., $%%9). & ;n $%%$, -;#; published the first edition of the +oad and 8esistance 6actor Eesign #pecification developed at "niversity of Gissouri of 8olla and Hashington "niversity under the directions of Hei5Hen 4u ' and *heodore A. ?alambos (-;#;, $%%$) .9 0oth -#E and +86E #pecifications were combined into a single specification in $%%9 (-;#;, $%%9). 2 ;n 7==$, the first edition of the Corth -merican #pecification for the Eesign of !old56ormed #teel #tructural Gembers was developed by a joint effort of the -;#; !ommittee on #pecifications, the!anadian #tandards -ssociation (!#-) *echnical !ommittee on !old5 6ormed #teel #tructural Gembers, and !amara Cacional de la ;ndustria del ierro y del -cero (!-C-!B8@) in Gexico (-;#;, 7==$). 1 ;t included the -#E and +86E methods for the "nited #tates and Gexico together with the +imit #tates Eesign (+#E) method for !anada. *his Corth
-merican #pecification has been accredited by the -merican Cational #tandard ;nstitute ( -C#;) as an -C#; #tandard to supersede the $%%9 -;#; #pecification and the $%%' !#- #tandard. 6ollowing the successful use of the 7==$ edition of the Corth -merican #pecification for six years, it was revised and expanded in 7==2 .% *his updated specification includes new and revised design provisions with the additions of the Eirect #trength Gethod in -ppendix $ and the #econd5@rder -nalysis of structural systems in -ppendix 7. ;n addition to the -;#; specifications, the -merican ;ron and #teel ;nstitute has also published commentaries on various editions of the specifications, design manuals, framing design standards, various design guides, and design aids for using cold5formed steel. 6or details, see -;#; & website.
!ommon section profiles and applications edit ;n building construction there are basically two types of structural steelI hot5rolled steel shapes and cold5formed steel shapes. *he hot rolled steel shapes are formed at elevated temperatures while the cold5formed steel shapes are formed at room temperature. !old5formed steel structural members are shapes commonly manufactured from steel plate, sheet metal or strip material. *he manufacturing process involves forming the material by either pressbraking or cold roll forming to achieve the desired shape. Hhen steel is formed by press5braking or cold rolled forming, there is a change in the mechanical properties of the material by virtue of the cold working of the metal. Hhen a steel section is cold5formed from flat sheet or strip the yield strength, and to a lesser extent the ultimate strength, are increased as a result of this cold working, particularly in the bends of the section. #ome of the main properties of cold formed steel are as followsI $= •
+ightness in weight
•
igh strength and stiffness
•
Base of prefabrication and mass production
•
6ast and easy erection and installation
•
#ubstantial elimination of delays due to weather
•
Gore accurate detailing
•
Con shrinking and non creeping at ambient temperatures
•
Co formwork needed
•
*ermite5proof and rot proof
•
"niform quality
•
Bconomy in transportation and handling
•
Con combustibility
•
8ecyclable material
•
anels and decks can provide enclosed cells for conduits.
- broad classification of the cold5formed shapes used in the construction industry can be made as individual structural framing members or panels and decks. #ome of the popular applications and the preferred sections areI •
8oof and wall systems (industrial, commercial, and agricultural buildings)
•
#teel racks for supporting storage pallets
•
#tructural members for plane and space trusses
•
6rameless #tressed skin structuresI !orrugated sheets or sheeting profiles with stiffened edges are used for small structures up to a := ft clear span with no interior framework
!6# Eecking
!6# purlins
!6# 5braced wall system
!6# studKgirt wall connection
*he -;#; #pecification allows the use of steel to the following -#*G specifications in the table belowI $$
Steel Designation
Carbon structural steel
+ig!-strengt! lo,allo" Structural steel
ASTM Designation
Product
ield
Tensile
Strengt!
Strengt!
F" (ksi)
Fu (ksi)
Minimum Fu #
$longation
F"
(%) in &-in' age Lengt!
A*
:9
&151=
$.9$ 7:
A*
&=
2=
$.'
A&&
'9
92
$.'9 7$
7'
'&59=
$.11 :=
7$
Lo, and intermediate tensile strengt!
A&.
carbon steel plates
A
/
72
&=59&
$.1& 71
C
:=
&&52&
$.1: 7&
D
::
9=51=
$.17 7:
A
::
'&
$.:9 7&
/
'7
&1
$.:1 7:
C
'9
97
$.:& 7$
D
:9
&1
$.9$ 7:
A
:%
'&
$.$& 7&
/
'9
&1
$.79 7:
C
&=
97
$.7' 7$
Cold-formed ,elded and seamless carbon steel structural tubing
A011
2ound Tubing
in rounds and s!apes
S!ape Tubing
D
:9
&1
$.9$ 7:
A0&4 r' &
'7
9=51&
$.': 77
A0&4 r' 01
&=
2=5$==
$.'= 7$
r' 1
:=
'%
$.9: 7$
r'
::
&7
$.&1 $1
r' *
:9
&:
$.'2 $2
r' 1
'=
&&
$.:1 $&
r' 0
'&
9=
$.:: $:
r' 01
&=
9&
$.:= $$
+ig!-strengt! carbon3manganese steel
+ot-rolled carbon steel s!eets and strips of structural
A061
5ualit"
+ig!-strengt! lo,allo" columbium3 7anadium steels of structural 5ualit"
A06&
r' &
'7
9=
$.': 7'
r' 01
&=
9&
$.:= 7$
r' *1
9=
2&
$.7& $1
r' *0
9&
1=
$.7: $2
A0..
&=
2=
$.'= 7$
&=
2=
$.'= 77
'&
9&
$.'' 77
'&
9&
$.'' 77
'&
9&
$.'' 77
+ig!-strengt! lo,allo" structural steel ,it! 01 ksi minimum "ield point
+ot-rolled and coldrolled !ig!-strengt! lo,-allo" steel s!eet and strip ,it! impro7ed corrosion
+ot-rolled A*1*
as rolled cut lengt!
resistance
+ot-rolled as rolled coils
+ot-rolled annealed
Coldrolled
+ot-rolled and coldrolled !ig!-strengt! lo,-allo" columbium A*16 Class 8 and#or 7anadium steel s!eet and strip
ot rolled (7:) r'0
'&
9=
$.::
!old rolled (77) ot rolled (7=)
r'01
&=
9&
$.:= !old rolled (7=) ot rolled ($1)
r'00
&&
2=
$.72 !old rolled ($1) ot rolled ($9)
r'*1
9=
2&
$.7& !old rolled ($9) ot rolled ($')
r'*0
9&
1=
$.7: !old rolled ($&) ot rolled ($7)
r'61
2=
1&
$.7$ !old rolled ($')
A*16 Class 88 ot rolled (7:) r'0
'&
&&
$.77 !old rolled (77)
ot rolled (7=) r'01
&=
9=
$.7= !old rolled (7=) ot rolled ($1)
r'00
&&
9&
$.$1 !old rolled ($1) ot rolled ($9)
r'*1
9=
2=
$.$2 !old rolled ($9) ot rolled ($')
r'*0
9&
2&
$.$& !old rolled ($&) ot rolled ($7)
r'61
2=
1=
$.$' !old rolled ($')
Cold-rolled carbon structural steel s!eet
A*99 A
7&
'7
$.91 79
/
:=
'&
$.&= 7'
C
::
'1
$.'& 77
D
'=
&7
$.:= 7=
r'
::
'&
$.:9 7=
r' 6
:2
&7
$.'$ $1
r' 1
'=
&&
$.:1 $9
01 Class 9
&=
9&
$.:= $7
01 Class
&=
2=
$.'= $7
:inc-coated or ;inciron allo"-coated
A*0 SS
steel s!eet
+SLAS T"pe A 01
&=
9=
$.7= 7=
*1
9=
2=
$.$2 $9
61
2=
1=
$.$' $7
.1
1=
%=
$.$: $=
01
&=
9=
$.7= 77
*1
9=
2=
$.$2 $1
61
2=
1=
$.$' $'
.1
1=
%=
$.$: $7
r' 01
&=
9=
$.7= 77
r' *1
9=
2=
$.$2 $1
r' 61
2=
1=
$.$' $'
r' .1
1=
%=
$.$: $7
r'
::
'&
$.:9 7=
r' 6
:2
&7
$.'$ $1
r' 1
'=
&&
$.:1 $9
r' 01A
&=
9&
$.:= $7
A.6
&=
2=
$.'=
%$+SLAS T"pe /
+ot-rolled and coldrolled !ig!-strengt! lo,-allo" steel s!eets
A690
and strip ,it! impro7ed formabilit"
00% aluminum-;inc allo"-coated steel s!eet b" t!e !ot-dip
A64&
process
Cold-formed ,elded and seamless !ig!strengt!< lo,-allo" structural tubing ,it!
impro7ed atmosp!eric corrosion resistance :inc-0% aluminum allo"-coated steel s!eet b" t!e !ot-dip
A.60 SS
process r'
::
'&
$.:9 7=
r' 6
:2
&7
$.'$ $1
r' 1
'=
&&
$.:1 $9
01 Class 9
&=
9&
$.:= $7
01 Class
&=
2=
$.'= $7
01
&=
9=
$.7= 7=
*1
9=
2=
$.$2 $9
61
2=
1=
$.$' $7
.1
1=
%=
$.$: $=
01
&=
9=
$.7= 77
*1
9=
2=
$.$2 $1
61
2=
1=
$.$' $'
.1
1=
%=
$.$: $7
+SLAS T"pe A
+SLAS T"pe /
*ypical stressFstrain properties edit - main property of steel, which is used to describe its behavior, is the stressFstrain graph. *he stressFstrain graphs of cold5formed steel sheet mainly fall into two categories. *hey are sharp yielding and gradual yielding type illustrated below in 6ig.$ and 6ig.7, respectively.
*hese two stressFstrain curves are typical for cold5formed steel sheet during tension test. *he second graph is the representation of the steel sheet that has undergone the cold5reducing (hard rolling) during manufacturing process, therefore it does not exhibit a yield point with a yield plateau. *he initial slope of the curve may be lowered as a result of the prework. "nlike 6ig.7, the stressFstrain relationship in 6ig.$ represents the behavior of annealed steel sheet. 6or this type of steel, the yield point is defined by the level at which the stressFstrain curve becomes hori/ontal. !old forming has the effect of increasing the yield strength of steel, the increase being the consequence of cold working well into the strain5hardening range. *his increase is in the /ones where the material is deformed by bending or working. *he yield stress can be assumed to have been increased by $&L or more for design purposes. *he yield stress value of cold5formed steel is usually between ::ksi and 1=ksi. *he measured values of Godulus of Blasticity based on the standard methods usually range from &4<111 to 1<111 ksi (&11 to &16 Pa) . - value of 7%,&== ksi (7=: ?a) is recommended by -;#; in its specification for design purposes. *he ultimate tensile strength of steel sheets in the sections has little direct relationship to the design of those members. *he load5carrying capacities of cold5formed steel flexural and compression members are usually limited by yield point or buckling stresses that are less than the yield point of steel, particularly for those compression elements having relatively large flat5width ratios and for compression members having relatively large slenderness ratios. *he exceptions are bolted and welded connections, the strength of which depends not only on the yield point but also on the ultimate tensile strength of the material. #tudies indicate that the effects of cold work on formed steel members depend largely upon the spread between the tensile and the yield strength of the virgin material.
Euctility criteriaedit
Euctility is defined as MMan extent to which a material can sustain plastic deformation without rupture.NN ;t is not only required in the forming process but is also needed for plastic redistribution of stress in members and connections, where stress concentration would occur. *he ductility criteria and performance of low5ductility steels for cold5formed members and connections have been studied by D!alla, =inter , and $rrera at !ornell "niversity. ;t was found that the ductility measurement in a standard tension test includes local ductility and uniform ductility. +ocal ductility is designated as the locali/ed elongation at the eventual fracture /one. "niform ductility is the ability of a tension coupon to undergo si/eable plastic deformations along its entire length prior to necking. *his study also revealed that for the different ductility steels investigated, the elongation in 75in. (&=.15mm) gage length did not correlate satisfactorily with either the local or the uniform ductility of the material. ;n order to be able to redistribute the stresses in the plastic range to avoid premature brittle fracture and to achieve full net5section strength in a tension member with stress concentrations, it is suggested thatI *he minimum local elongation in a 5 $F7 in. ($7.25mm) gauge length of a standard
•
tension coupon including the neck be at least 7=L. *he minimum uniform elongation in a :5in. (29.75mm) gauge length minus the elongation
•
in a $5in. (7&.'5mm) gage length containing neck and fracture be at least :L. *he tensile5strength5to5yield5point ratio 6u K6y be at least $.=&.
•
Heldabilityedit Heldability refers to the capacity of steel to be welded into a satisfactory, crack free, sound joint under fabrication conditions without difficulty .$ Helding is possible in cold5formed steel elements, but it shall follow the standards given in -;#; S911-&116< Section $. $.=!en t!ickness less t!an or e5ual to #9*> ('6*mm)? *he various possible welds in cold formed steel sections, where the thickness of the thinnest element in the connection is :K$9O or less are as follows •
•
?roove Helds in 0utt joints
•
-rc #pot Helds
•
-rc #eam Helds
•
6illet Helds
•
6lare ?roove Helds
7.=!en t!ickness greater t!an or e5ual to #9*> ('6*mm)? Helded connections in which thickness of the thinnest connected arc is greater than :K$9O ('.29mm) shall be in accordance with A@S8#A8SC-*1. *he weld positions are covered as per A8S8 S911-&116 (*able B7a) %
Minimum material t!ickness recommended for ,elding connections edit Application
!6# to #tructural
S!op or Field fabrication
$lectrode met!od
Suggested minimum CFS t!ickness
6ield5fabrication
#tick5welding
&' mils to 91 mils
#hop5fabrication
#tick5welding
&' mils to 91 mils
!6# to !6#
6ield5fabrication
#tick5welding
&' mils to 91 mils
!6# to !6#
6ield5fabrication
!6# to !6#
#hop5fabrication
steel
!6# to #tructural steel
$7
-pplication in buildings edit
Hire5fed G;? (Getal ;nert ?as) welding
Hire5fed G;? (Getal ;nert ?as) welding
': mils to &' mils
:: mils
Cold-formed steel framing edit !old5formed steel framing (!6#6) refers specifically to members in light5frame building construction that are made entirely of sheet steel, formed to various shapes at ambient temperatures. *he most common shape for !6#6 members is a lipped channel, although PQO, P!O, tubular, PhatO and other shapes and variations have been used. *he building elements that are most often framed with cold5formed steel are floors, roofs, and walls, although other building elements and both structural and decorative assemblies may be steel framed. -lthough cold5formed steel is used for several products in building construction, framing products are different in that they are typically used for wall studs, floor joists, rafters, and truss members. Bxamples of cold5formed steel that would not be considered framing includes metal roofing, roof and floor deck, composite deck, metal siding, and purlins and girts on metal buildings. 6raming members are typically spaced at $9 or 7' inches on center, with spacing variations lower and higher depending upon the loads and coverings. Hall members are typically vertical lipped channel PstudO members, which fit into unlipped channel PtrackO sections at the top and bottom. #imilar configurations are used for both floor joist and rafter assemblies, but in a hori/ontal application for floors, and a hori/ontal or sloped application for roof framing. -dditional elements of the framing system include fasteners and connectors, braces and bracing, clips and connectors. ;n Corth -merica, member types have been divided into five major categories, and product nomenclature is based on those categories. •
# members are lipped channels, most often used for wall studs, floor joists, and ceiling or roof rafters.
•
* members are unlipped channels, which are used for top and bottom plates (tracks) in walls, and rim joists in floor systems. *racks also form the heads and sills of windows, and typically cap the top and bottom of boxed5 or back5to5back headers.
•
" members are unlipped channels that have a smaller depth than tracks, but are used to brace members, as well as for ceiling support systems.
•
6 members are PfurringO or PhatO channels, typically used hori/ontally on walls or ceilings.
•
+ members are angles, which in some cases can be used for headers across openings, to distribute loads to the adjacent jamb studs.
;n high5rise commercial and multi5family residential construction, !6#6 is typically used for interior partitions and support of exterior walls and cladding. ;n many mid5rise and low5rise applications, the entire structural system can be framed with !6#6.
Connectors and fasteners in framing edit !onnectors are used in cold5formed steel construction to attach members (i.e. studs, joists) to each other or to the primary structure for the purpose of load transfer and support. #ince an assembly is only as strong as its weakest component, it is important to engineer each connection so that it meets specified performance requirements. *here are two main connection types,Fied and Mo7ement-Allo,ing (#lip). 6ixed connections of framing members do not allow movement of the connected parts. *hey can be found in axial5load bearing walls, curtain walls, trusses, roofs, and floors. Govement5-llowing connections are designed to allow deflection of the primary structure in the vertical direction due to live load, or in the hori/ontal direction due to wind or seismic loads, or both vertical and hori/ontal directions. @ne application for a vertical movement5allowing connection is to isolate non5axial load bearing walls (drywall) from the vertical live load of the structure and to prevent damage to finishes. ;f the structure is in an active seismic /one, vertical and hori/ontal movement5allowing connections may be used to accommodate both the vertical deflection and hori/ontal drift of the structure. !onnectors may be fastened to cold5formed steel members and primary structure using welds, bolts, or self5drilling screws. *hese fastening methods are recogni/ed in the -merican ;ron and #teel ;nstitute (-;#;) 7==2 Corth -merican #pecification for the Eesign of !old56ormed #teel #tructural Gembers, !hapter B. @ther fastening methods, such as clinching, power actuated fasteners (-6), mechanical anchors, adhesive anchors and structural glue, are used based on manufacturers performance5based tests.
ot5rolled versus cold5rolled steel and the influence of annealingedit +ot rolled
Cold rolled
*he material is not deformed< Material
ielding
properties
strengt!
there is no initial strain in the
*he yield value is increased by
material, hence yielding starts $&LF:=L due to prework (initial at actual yield value as the original material.
deformation).
Modulus of
7%,=== ksi
7%,&== ksi
elasticit"
Bnit ,eig!t
"nit weight is comparatively huge.
Ductilit" Gore ductile in nature.
Gost of the time, we consider Design
+ess ductile.
+ocal buckling, Eistortional
only the global buckling of the 0uckling, ?lobal 0uckling have to member.
+oad bearing structures, usually heavy load bearing Main uses
;t is much smaller.
structures and where ductility is more important ( Bxample #eismic prone areas)
be considered.
-pplication in many variety of loading cases. *his includes building frames, automobile, aircraft, home appliances, etc. "se limited in cases where high ductility requirements.
#tandard shapes are Fleibilit" of s!apes
followed. igh value of unit
-ny desired shape can be molded
weight limits the flexibility of
out of the sheets. *he light weight
manufacturing wide variety of
enhances its variety of usage.
shapes.
igh "nit weight increases $conom"
the overall cost F material,
+ow unit weight reduces the cost
lifting, transporting, etc. ;t is
comparatively. Base of construction
difficult to work with (e.g.
(e.g. connection).
connection).
2esearc! possibilities
;n the advanced stages at present.
Gore possibilities as the concept is relatively new and material finds wide variety of applications.
-nnealing, also described in the earlier section, is part of the manufacturing process of cold5 formed steel sheet. ;t is a heat treatment technique that alters the microstructure of the cold5 reducing steel to recover its ductility.
reference:
htt#://en)wiki#edia)org/wiki/+old-formedsteel
!elded built-up columns Builtup columns are used in steel construction when the column buckling lengths are large and the compression forces are relatively low. This guide covers two types of builtup columns2
Builtup columns with lacing
Builtup columns with battens.
This document includes an overview of common details for such members. 7t describes the design method according to & 1==(11L1M for the determination of the internal forces and the buckling resistance of each member Echords, diagonals, etcG of builtup columns made of ho t rolled profiles. 7t should be noted that due to the shear deformation, battened builtup columns are more fleible than solid columns with the same inertia* this must be taken into account in the design. 7n order to derive the aial resistance of a steel builtup column, the following must be addressed2
"nalysis of the builtup column to determine the internal forces by taking
into account an equivalent initial imperfection and the second order effects
3erification of the chords and bracing members Ediagonals and battensG
3erification of the connections.
" fully worked eample of a builtup column with an shape arrangement of lacings is given in "ppendi ", which illustrates the design principles.
T)ES O% 1+I#T"+) 2E21E$S *N& TEI$ *))#IC*TION
'.1 eneral 7n general, builtup columns are used in industrial buildings, either as posts for cladding when their buckling length is very long, or as columns supporting a crane girder. /hen used as a post for cladding with pinned ends, the column is designed to support the hori#ontal forces, mainly due to wind. Hence the bending moment in such a builtup column is predominant compared to the compression force.
B ty#ical built-u# column that su##orts a crane girder is shown in %igure 2)2) "hey usually ha(e a Lxed base and a #inned end at the to#* and are designed to resist: "he com#ression forces that result either from the frame or from the crane rail "he horiNontal forces that result from the e,ects of the crane a##lied on the internal chord and the wind loads a##lied to the external one) Hn this case* the com#ression forces are #redominant com#ared to the bending moment)
"he built-u# columns are com#osed of two #arallel chords interconnected by lacings or battens O see %igure 2)!) Hn general* the truss system concentrates material at the structurally most ecient locations for force transfer) Hn an industrial building and for a gi(en height* built u# columns theoretically ha(e the least steel weight of any steel framing system) Bny hot rolled section can be used for the chords and the web members of built-u# columns) Eowe(er* channels or H-sections are most commonly used as chords) "heir combination with angles #resents a con(enient technical solution for built-u# columns with lacing or battens) %lat bars are also used in built-u# column as battens) "his guide co(ers two ty#es of built-u# columns with #inned ends that are assumed to be laterally su##orted: &aced columns
attened columns)
"he di,erence between these two ty#es of built-u# columns comes from the mode of connection of the web members Ilacings and battensJ to the chords) "he Lrst ty#e contains diagonals Iand #ossibly strutsJ designed with #inned ends) "he second ty#e in(ol(es battens with Lxed ends to the chords and functioning as a rectangular #anel) "he inertia of the built-u# column increases with the distance between the chord axes) "he increase in sti,ness is counterbalanced by the weight and cost increase of the connection between members) uilt-u# columns #ro(ide relati(ely light structures with a large inertia) Hndeed* the #osition of the chords* far from the centroid of the built-u# section* is (ery beneLcial in #roducing a great inertia) "hese members are generally intended for tall structures for which the horiNontal dis#lacements are limited to low (alues Ie)g) columns su##orting crane girdersJ) "he axial resistance of built-u# columns is largely a,ected by the shear deformations) "he initial bow im#erfection is signiLcantly am#liLed because of the shear strains) Ht is #ossible to study the beha(iour of built-u# columns using a sim#le elastic model)
Laced built-up columns &'&'9 eneral
"here is a large number of laced column conLgurations that may be considered) Eowe(er* the 3-sha#e and the A-sha#e arrangements of lacings are commonly used)
Figure &' /uilt-up column ,it! lacings in an industrial building
"he selection of either channels or H-sections for chord members #ro(ides di,erent ad(antages) H-sections are more structurally ecient and therefore are #otentially shallower than channels) %or built-u# columns with a large com#ressi(e axial force Ifor exam#le* columns su##orting cranesJ* H or E sections will be more a##ro#riate than channels) +hannels may be ade1uate in order to #ro(ide two Mat sides) "ee sections cut from
"he 3-sha#e arrangement of lacings* as shown in %igure 2)5IaJ* can be considered as the most ecient truss conLguration* for ty#ical frames in industrial buildings) "he web of the 3-sha#e arrangement com#rises diagonals and #osts that meet at the same #oint on the chord axes) "his arrangement reduces the length of the com#ression chords and diagonals) Ht is usually used in frames with a signiLcant uniform com#ressi(e force) "he A-sha#e arrangement of lacings increases the length of the com#ression chords and diagonals and #ro(ides a reduction of buckling resistance of the members) "his arrangement is used in frames with a low com#ressi(e force) "he @-sha#e conLgurations are not generally used in buildings because of the cost and the com#lexity of fabrication)
U
&'&' Construction details
6ingle lacing systems on o##osite faces of the built-u# member with two #arallel laced #lanes should be corres#onding systems as shown in %igure 2)IaJ I<3 !QQ-!-! R )4)2)2I!JJ) ?hen the single lacing systems on o##osite faces of a built-u# member with two #arallel laced #lanes are mutually o##osed in direction* as shown in %igure 2)IbJ* the resulting torsional e,ects in the member should be taken into account) "he chords must be designed for the additional eccentricity caused by the trans(erse bending e,ect* which can ha(e a signiLcant inMuence on the
member siNe) "ie #anels should be #ro(ided at the ends of lacing systems* at #oints where the lacing is interru#ted and at Koints with other members)
&' /attened built-up columns attened built-u# columns are not a##ro#riate for frames in industrial buildings) "hey are sometimes used as isolated frame members in s#eciLc conditions* where the horiNontal forces are not signiLcant) +hannels or H-sections are mostly used as chords and Mat bars are used as battens) "he battens must ha(e Lxed ends on the chords) attened built-u# columns are com#osed of two #arallel #lanes of battens which are connected to the Manges of the chords) "he #osition of the battens
should be the same for both #lanes) attens should be #ro(ided at each end of the built-u# member) attens should also be #ro(ided at intermediate #oints where loads are a##lied* and at #oints of lateral restraint)
reference: htt#://www)arcelormittal)com/sections/Lleadmin/redaction/4-&ibrary/46
hallo! precast "oor beams - !ollo, core slab, also known as a 7oided slab or !ollo, core plank, is a precast slab of prestressed concrete typically used in the construction of floors in multi5story apartment
buildings. *he slab has been especially popular in countries where the emphasis of home construction has been on precast concrete, including Corthern Burope and socialist countries of Bastern Burope. recast concrete popularity is linked with low5seismic /ones and more economical constructions because of fast building assembly, lower self weight (less material), etc. *he precast concrete slab has tubular voids extending the full length of the slab, typically with a diameter equal to the 7K:5:K' of the slab. *his makes the slab much lighter than a massive floor slabs of equal thickness or strength. 8educed weight is important because of transportation cost and less cost of material (concrete). *he slabs are typically $7= cm wide with standard thicknesses between $& cm and &= cm. *he precast concrete ;5beamsbetween the holes contain the steel wire rope that provide bending resistance to bending moment from loads. #labs in prestressed concrete are usually produced in lengths of about $7= meters. *he process involves extruding wet concrete along with the prestressed steel wire rope from a moving mold. *he continuous slab is then cut by big diamond circular saw according to the lengths (and width) required on blueprint. 6actory production provides the obvious advantages of reduced time, labor and training. -nother fabrication system produces hollow5core floorslabs in 8einforced !oncrete (not prestressed). *hese are made on carousel production lines, directly to exact length, and as a stock product. -lthough the length is limited to about 251 metre, this type is much more cost effective (needs less people, and is faster). Bspecially in 0elgium, this method is widely used in private housing. *o meet modern standards (both hollow5core and massive slab) of soundproofing the floor needs to be covered with a soft floor covering that is able to dampen the sound of footsteps. -n alternative is to use a thin 3floating3 slab of concrete insulated from the voided slabs.
Eiagram of a concrete slab of hollow core construction
ollowcore benefits
)lear, unpropped spans Fast and simple to erect 8rovides an immediate working platform )an be used in all types of structure -asonry, steel and concrete
&cellent sound and fire resistance &asier installation of services Holes and notches preformed during manufacture ?uality service guaranteed "vailable nationwide either supply only or supply and fi Factory manufacture to consistent quality standards )omplies with all relevant standards and manufactured in accordance with B! & 7!> =991 and B! & 7!>1+9991
reference
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precast prestressed concrete "oor units
steel ring spacer
"oor reinforcement cage
precast concrete !all frame
stud frames Framing, in construction known as lig!t-frame construction, is a building technique based around vertical structural members, usually called studs, which provide a stable frame to which interior and exterior wall coverings are attached, and covered by a roof made of hori/ontal ceiling joists and sloping rafters (or pre5fabricated roof trusses). Godern light5frame structures usually gain strength from rigid panels ( plywood and other plywood5like composites such as oriented strand board (@#0) used to form all or part of wall sections) but until recently carpenters employed various forms of diagonal bracing (called wind braces) to stabili/e walls. Eiagonal bracing remains a vital interior part of many roof systems, and in5wall wind braces are required by building codes in many municipalities or by individual state laws in the "nited #tates. +ight frame construction using standardi/ed dimensional lumber has become the dominant construction method in Corth -merica and -ustralia because of its economy. "se of minimal structural materials allows builders to enclose a large area with minimal cost, while achieving a wide variety of architectural styles. *he ubiquitous platform framing and the older balloon framing are the two different light frame construction systems used in Corth -merica.
- wooden5frame house under construction F in this example of platform framing the location of the upper floor is readily discerned by the wide joists between the floors, and the upper structure rests on this platform.
Hallsedit Hall framing in house construction includes the vertical and hori/ontal members of exterior walls and interior partitions, both of bearing walls and non5bearing walls. *hese stick members, referred to as studs, wall plates and lintels (headers), serve as a nailing base for all covering material and support the upper floor platforms, which provide the lateral strength along a wall. *he platforms may be the boxed structure of a ceiling and roof, or the ceiling and floor joists of the story above. $ *he technique is variously referred to colloquially in the building trades as stick and frame, stick and platform, or stick and box as the sticks (studs) give the structure its vertical support, and the box shaped floor sections with joists contained within length5long post and lintels (more commonly called headers), supports the weight of whatever is above, including the next wall up and the roof above the top story. *he platform also provides the lateral support against wind and holds the stick walls true and square. -ny lower platform supports the weight of the platforms and walls above the level of its component headers and joists. 6raming lumber should be grade5stamped, and have a moisture content not exceeding $%L.
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*here are three historically common methods of framing a house. •
ost and beam, which is now used predominately in barn construction.
•
0alloon framing using a technique suspending floors from the walls was common until the late $%'=s, but since that time, platform framing has become the predominant form of house construction.:
•
latform framing often forms wall sections hori/ontally on the sub5floor prior to erection, easing positioning of studs and increasing accuracy while cutting the necessary manpower. *he top and bottom plates are end5nailed to each stud with two nails at least :.7& in (1: mm) in length (16d or 16 penny nails). #tuds are at least doubled (creating posts) at openings, the jack stud being cut to receive the lintels(headers) that are placed and end5 nailed through the outer studs. :
Hall sheathing, usually a plywood or other laminate, is usually applied to the framing prior to erection, thus eliminating the need to scaffold, and again increasing speed and cutting manpower needs and expenses. #ome types of exterior sheathing, such as asphalt5 impregnated fibreboard, plywood, oriented strand board and waferboard, will provide adequate bracing to resist lateral loads and keep the wall square. (!onstruction codes in most jurisdictions require a stiff plywood sheathing.) @thers, such as rigid glass5fibre, asphalt5coated fibreboard, polystyrene or polyurethane board, will not. $ ;n this latter case, the wall should be reinforced with a diagonal wood or metal bracing inset into the studs.
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;n jurisdictions subject to
strong wind storms (hurricane countries, tornado alleys) local codes or state law will generally require both the diagonal wind braces and the stiff exterior sheathing regardless of the type and kind of outer weather resistant coverings.
Corners edit - multiple5stud post made up of at least three studs, or the equivalent, is generally used at exterior corners and intersections to secure a good tie between adjoining walls and to provide nailing support for the interior finish and exterior sheathing. !orners and intersections, however, must be framed with at least two studs. & Cailing support for the edges of the ceiling is required at the junction of the wall and ceiling where partitions run parallel to the ceiling joists. *his material is commonly referred to as dead wood9or backing.
$terior ,all studs edit Hall framing in house construction includes the vertical and hori/ontal members of exterior walls and interior partitions. *hese members, referred to as studs, wall plates and lintels, serve as a nailing base for all covering material and support the upper floors, ceiling and roof.
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Bxterior wall studs are the vertical members to which the wall sheathing and cladding are attached. 2 *hey are supported on a bottom plate or foundation sill and in turn support the top plate. #tuds usually consist of $.& in R :.& in (:1 mm R 1% mm) or $.& in R &.& in (:1 mm R $'= mm) lumber and are commonly spaced at $9 in ('$= mm) on centre. *his spacing may be changed to $7 in (:== mm) or 7' in (9$= mm) on centre depending on the load and the limitations imposed by the type and thickness of the wall covering used. Hider $.& in R &.& in (:1 mm R $'= mm) studs may be used to provide space for more insulation. ;nsulation beyond that which can be accommodated within a :.& in (1% mm) stud space can also be provided by other means, such as rigid or semi5rigid insulation or batts between $.& in R $.& in (:1 mm R :1 mm) hori/ontal furring strips, or rigid or semi5rigid insulation sheathing to the outside of the studs. *he studs are attached to hori/ontal top and bottom wall plates of $.& in (:1 mm) lumber that are the same width as the studs. 7
8nterior partitions edit ;nterior partitions supporting floor , ceiling or roof loads are called loadbearing walls< others are called non5loadbearing or simply partitions. ;nterior loadbearing walls are framed in the same way as exterior walls. #tuds are usually $.& in R :.& in (:1 mm R 1% mm) lumber spaced at $9 in ('$= mm) on centre. *his spacing may be changed to $7 in (:== mm) or 7' in (9$= mm) depending on the loads supported and the type and thickness of the wall finish used .& artitions can be built with $.& in R 7.& in (:1 mm R 9' mm) or $.& in R :.& in (:1 mm R 1% mm) studs spaced at $9 or 7' in ('== or 9== mm) on center depending on the type and thickness of the wall finish used. Hhere a partition does not contain a swinging door, $.& in R :.& in (:1 mm R 1% mm) studs at $9 in ('$= mm) on centre are sometimes used with the wide face of the stud parallelto the wall. *his is usually done only for partitions enclosing clothes closets or cupboards to save space. #ince there is no vertical load to be supported by partitions, single studs may be used at door openings. *he top of the opening may be bridged with a single piece of $.& in (:1 mm) lumber the same width as the studs. *hese members provide a nailing support for wall finish, door frames and trim.&
Lintels (!eaders) edit +intels (or, headers) are the hori/ontal members placed over window, door and other openings to carry loads to the adjoining studs. $ +intels are usually constructed of two pieces of 7 in (nominal) (:1 mm) lumber separated with spacers to the width of the studs and nailed together to form a single unit. *he preferable spacer material is rigid insulation.
2
*he depth of a lintel is
determined by the width of the opening and vertical loads supported.
=all sectionsedit *he complete wall sections are then raised and put in place, temporary braces added and the bottom plates nailed through the subfloor to the floor framing members. *he braces should have their larger dimension on the vertical and should permit adjustment of the vertical position of the wall.' @nce the assembled sections are plumbed, they are nailed together at the corners and intersections. - strip of polyethylene is often placed between the interior walls and the exterior wall, and above the first top plate of interior walls before the second top plate is applied to attain continuity of the air barrier when polyethylene is serving this function. ' - second top plate, with joints offset at least one stud space away from the joints in the plate beneath, is then added. *his second top plate usually laps the first plate at the corners and partition intersections and, when nailed in place, provides an additional tie to the framed walls.
Hhere the second top plate does not lap the plate immediately underneath at corner and partition intersections, these may be tied with =.=:9 in (=.%$ mm) galvani/ed steel plates at least : in (29 mm) wide and 9 in ($&= mm) long, nailed with at least three 7.& in (9' mm) nails to each wall.'
0alloon framingedit
0alloon framing is a method of wood construction F also known as 3!hicago construction3 in the $%th century1 F used primarily in#candinavia, !anada and the "nited #tates (up until the mid5 $%&=s). ;t utili/es long continuous framing members (studs) that run from the sill plate to the top plate, with intermediate floor structures let into and nailed to them.
%$=
ere the heights of
window sills, headers and next floor height would be marked out on the studs with a storey pole. @nce popular when long lumber was plentiful, balloon framing has been largely replaced by platform framing . ;t is not certain who introduced balloon framing in the "nited #tates. owever, the first building using balloon framing was probably a warehouse constructed in $1:7 in !hicago, ;llinois, by ?eorge Hashington #now.$$ *he following year, -ugustine *aylor ($2%9F$1%$) constructed #t. Garys !atholic !hurch in !hicago using the balloon framing method. ;n the $1:=s, oosier #olon 8obinson published articles about a revolutionary new framing system, called Pballoon framingO by later builders. 8obinsonNs system called for standard 7x'
lumber, nailed together to form a sturdy, light skeleton. 0uilders were reluctant to adopt the new technology, however, by the $11=s, some form of 7x' framing was standard.
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-lternatively, the balloon frame has been shown to have been introduced in Gissouri as much as fifty years earlier. $: *he name comes from a 6rench Gissouri type of construction, maison en boulin,$: boulin being a 6rench term for a hori/ontal scaffolding support. istorians have also fabricated the following storyI $' -s *aylor was constructing his first such building, #t. Garys !hurch, in $1::, skilled carpenters looked on at the comparatively thin framing members, all held together with nails, and declared this method of construction to be no more substantial than a balloon. ;t would surely blow over in the next windD *hough the criticism proved baseless, the name stuck.
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-lthough lumber was plentiful in $%th5century -merica, skilled labor was not. *he advent of cheap machine5made nails, along with water5powered sawmills in the early $%th century made balloon framing highly attractive, because it did not require highly5skilled carpenters, as did the dovetail joints, mortises and tenons required by post5and5beam construction. 6or the first time, any farmer could build his own buildings without a time5consuming learning curve. $9 ;t has been said that balloon framing populated the western "nited #tates and the western provinces of !anada. Hithout it, western boomtowns certainly could not have blossomed overnight. $2 ;t is also a fair certainty that, by radically reducing construction costs, balloon framing improved the shelter options of poorer Corth -mericans. citation needed 6or example, many $%th5century Cew Bngland working neighborhoods consist of balloon5constructed three5story apartment buildings referred to as triple deckers.
- very unusual example of balloon framingI *he Jim Saney 8ound 0arn, -deline, ;llinois, ".#.-.
*he main difference between platform and balloon framing is at the floor lines. *he balloon wall studs extend from the sill of the first story all the way to the top plate or end rafter of the second story. *he platform5framed wall, on the other hand, is independent for each floor.
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0alloon framing has several disadvantages as a construction methodI $. *he creation of a path for fire to readily travel from floor to floor. *his is mitigated with the use of firestops at each floor level. 7. *he lack of a working platform for work on upper floors. Hhereas workers can readily reach the top of the walls being erected with platform framing, balloon construction requires scaffolding to reach the tops of the walls (which are often two or three stories above the working platform). :. *he requirement for long framing members. '. ;n certain larger buildings, a noticeable down5slope of floors towards central walls, caused by the differential shrinkage of the wood5framing members at the perimeter versus central walls. +arger balloon5framed buildings will have central bearing walls which are actually platform framed and thus will have hori/ontal sill and top plates at each floor level, plus the intervening floor joists, at these central walls. Hood will shrink much more across its grain than along the grain. *herefore, the cumulative shrinkage in the center of such a building is considerably more than the shrinkage at the perimeter where there are many fewer hori/ontal members. *his problem, unlike the first three, takes time to develop and become noticeable. &. resent5day balloon framing buildings often have higher heating costs, due to the lack of insulation separating a room from its exterior walls. owever, this can be remedied through the addition of insulation, as with any other framed building. #ince steel is generally more fire5resistant than wood, and steel framing members can be made to arbitrary lengths, balloon framing is growing in popularity again in light gauge steel stud construction. 0alloon framing provides a more direct load path down to the foundation. -dditionally, balloon framing allows more flexibility for tradesmen in that it is significantly easier to pull wire, piping and ducting without having to bore through or work around framing members. citation needed
latform framingedit ;n !anada and the "nited #tates, the most common method of light5frame construction for houses and small apartment buildings as well as other small commercial buildings is platform framing . ;n builder parlance, platform framing might also nowadays be called (only partly correctly) stick framing' or stick construction' as each element is built up stick by stick, which was also true in the other stick framing method, in the obsolete and labor intensive, but
previously fashionable, balloon framing method, wherein the outside walls were erected, headers hung, then floor joists were inserted into a box made of walls. ;n contrast, in platform framing a floor box and joists making up the platform is built and placed on a supporting under structure ( #ill plates, headers, or beams) where it sits flat and gets fastened down against wind lifting with galvani/ed metal tie straps. @nce the boxed floor platform is squared, leveled and fastened then subfloor , walls, ceilings, and roof are built onto and above that initial platform, which can be repeated floor by floor, without the slow downs and dangers of fastening and leveling rough5sawn joists of a new floor together to the walls from ladders extending one or even two stories up. ?enerally, the flooring (platform) is constructed then the walls built on top of that layer, then another atop that, and so forth making for quick efficient labor saving construction methodologies and those have quickened further as technologies such as joist hangers have been developed to speed and enhance the technology. *he methods and techniques have become so common and pervasive that even #kyscrapers use a modified form of platform framing techniques and indeed the same tools and technologies once construction builds the initial structural skeleton. @nce the platform floor is laid down, the builders crew can with chalk line, rule and pencil directly transfer an outline of the exterior and interior walls, their openings and relative locations with ease and precision from the plans or builders blue prints. -s the survey group lays down the notations and chalk lines, a carpenter crew can follow behind and lay down 7x' bottom plates and tack them to the floor box. *he topmost wall plates are cut only to the outside dimensions of the walls. 0utting two other two by fours against these cut to si/e and fastened bottom plate allows the crew to rule across all three with square and lay out studs, cripple studs, and openings for that particular wall. *he two loose studs are then quickly flipped on edge after openings are cut in, and studs added on the marks with quick reliable end nailing through the respective top and bottom plates. - few minutes later the whole wall section can be levered up and aligned in place and braced for later application of the top plates and adjoining walls. *he method provides builders options and flexibility such as when and where there is a floor5 level opening (doorway) the next wall section can be aligned and fastened in place separately with the top plate added then used then a lintel and cripple studding added, or the entire wall could have been cut and joined at the top all along and lifted up as one entity. ;n the end, the outside walls are plumbed and fastened together with ell5configured reinforced corners that provide nailing wood in the interior angles and strength to the building forming in effect wide posts at each corner and fastened lastly by overlapped top plates which stagger their joints from the ones capping each plate by which the studs are end nailed together. Bach wall from top to bottom ends up with a doubled plate, studs, and a doubled plate, where structurally the doubled
plates spread the weight of the roof and loading across the studs of the wall, ultimately to the foundation. @verall, the framed structure sits (most commonly) atop a concrete foundation on pressure treated wood 'sill', or 'beam'. Hhen on concrete, the sill plate is anchored, usually with (embedded) J bolts into the concrete substrate of the foundation wall. ?enerally these plates must be pressure treated to keep from rotting from condensing moisture. 0y various standards the bottom of the sill plate is located a minimum 9 inches ($&= mm) above the finished grade (the surrounding ground) per standard builders practices, and frequently more dependent upon building codes of the relevant jurisdictions local building codes. ;n Corth -merica, building codes may differ not only state to state, but town to town, the tighter specification applying at all times. *his distance, together with roofing overhangs, and other system factors, is most often selected both to prevent the sill5plate from rotting (due to the invasion of splashed water) as well as providing a termite barrier. *he latter is particularly (more or less) important than anti5rotting considerations depending upon the geographical location. -lternatively, the room, room extension, deck or even a house can be built above concrete columns ".#. builders call piers some others call pilasters, another of many term misuses common to building trade parlance. ;n such cases, the pier (column) is usually required to rest on bed rock or extend well below the /one of average free/ing soil depth (the same as a foundation) locally, and frequently is required to also have flared out or mushroomed bottom of greater surface than that the pier top (*hese are called big foots in the building trade and building suppliers carry A! molds to conserve concrete which allow a builder to satisfy area requirements and the building codes). 8igid pressure treated beams (usually doubled or tripled up wider types of 7x boards) are attached to the piers using galvani/ed metal brackets and serve the same function as sills in foundation supported framing. *he floors, walls and roof of a framed structure are created by assembling (using nails) consistently si/ed framing elements of dimensional lumber (e.g. 7R's) at regular spacings (typically divisions of ' and 1 feet, or such as $7, $9, $%.7, or 7' inches on center). *he empty space formed between elements is called a stud bay in the wall and a joist bay in the floor or ceiling. *he floors, walls and roof are typically made torsionally stable with the installation of a plywood or composite wood skin referred to as sheathing citation needed . #heathing has very specific requirements (such as thickness and spacing of nailing). *hese measures allow a known amount of shear force to be resisted by the elements. #pacing the framing members properly usually allows them to align with the edges of standard sheathing. ;n the past, tongue and groove planks installed diagonally were used as sheathing. @ccasionally, wooden or galvani/ed steel braces are used instead of sheathing. *here are also engineered wood panels made for shear and bracing. citation needed
*he floor, or the platform in this framing types name, is made up of joists (usually 7x9, 7R1, 7R$= or 7R$7 depending on the span, on edge thus the wider joist supporting weight for a greater distance) that sit on supporting foundation walls, beams, columns or girders within and at right angle to doubled outside members also on edge (the band), forming a box. *he outer perimeter is nearly the same (: inch vs. :.& inches) width as the support sill. *he joists will generally be installed across the shortest distance of any floor span rectangle. *he outer layer of the band will overlap the inner layer with staggered end joints creating a stronger box. ;f joist hangers are not used, the installation of the outer board in the band is delayed to allow through5 nailing directly into the ends of the joists. *he floor joists are spaced at $7 in, $9 in, and 7' in on center, depending upon the live load needs of the design F the closer the spacing and the wider the floor joist dimension, the less the floor will flex. ;t is then usually covered with a :K'5inch tongue5and5groove plywood subfloor. ;n the century past, $x planks set at '&5degrees to the joists were used for the first subfloor layer, and a second layer of $x planks set at %=5degrees to the floor cladding topped that as the second subfloor layer. ;n that same era, all flooring choices were a very short menu of choices between finished wood types or ceramic tiles versus todays extensive multipage menu of manufactured flooring types. Hhere the design calls for a framed floor, the resulting platform is where the framer will construct and stand that floors walls (interior and exterior load bearing walls and space5dividing, non5load bearing partitions). -dditional framed floors and their walls may then be erected to a general maximum of four in wood framed construction. *here will be no framed floor in the case of a single5level structure with a concrete floor known as a slab on grade.citation needed #tairs between floors are framed by installing three %=T5stepped stringers attached to wall structures and then placing the hori/ontal treads and vertical risers (usually about $' of each for an 15ft. ceiling) upon the planes formed by the stringers. - framed roof is an assembly of rafters and wall5ties supported by the top storys walls. refabricated and site5built trussed rafters are also used along with the more common stick framing method. Trusses are engineered to redistribute tension away from wall5tie members and the ceiling members. *he roof members are covered with sheathing or strapping to form the roof deck for the finish roofing material. citation needed 6loor joists can be engineered lumber (trussed, ;5joist, etc.), conserving resources with increased rigidity and value. *hey are semi5custom manufactured to allow access for runs of plumbing, A-!, etc. and some 'common-needs' forms are pre5manufactured as semi5mass5 produced standard products made on a per order basis, like roofing trusses. #uch products have a post5order lead time from several weeks to several months.
Eouble framing is a style of framing used in some areas to reduce heat loss and air infiltration. *wo walls are built around the perimeter of the building with a small gap in between. *he inner wall carries the structural load of the building and is constructed as described above. *he exterior wall is not load bearing and can be constructed using lighter materials. ;nsulation is installed in the entire space between the outside edge of the exterior wall and the inside edge of the interior wall. *he si/e of the gap depends upon how much insulation is desired. *he vapor barrier is installed on the outside of the inner wall, rather than between the studs and drywall of a standard framed structure. *his increases its effectiveness as it is not perforated by electrical and plumbing connections.
Gaterialsedit +ight5frame materials are most often wood or rectangular steel tubes or !5channels. Hood pieces are typically connected with nails or screws< steel pieces are connected with nuts and bolts. referred species for linear structural members are softwoods such as spruce, pine and fir . +ight frame material dimensions range from :1 mm by 1% mm ($.& in by :.& in< i.e., a two5by5four ) to & cm by := cm (two5by5twelve inches) at the cross5section, and lengths ranging from 7.& m (1.7 ft) for walls to 2 m (7: ft) or more for joists and rafters. 8ecently, architects have begun experimenting with pre5cut modular aluminum framing to reduce on5site construction costs. citation needed Hall panels built of studs are interrupted by sections that provide rough openings for doors and windows. @penings are typically spanned by a header or lintel that bears the weight of structure above the opening. eaders are usually built to rest on trimmers, also called jacks. -reas around windows are defined by a sill beneath the window, and cripples, which are shorter studs that span the area from the bottom plate to the sill and sometimes from the top of the window to a header, or from a header to a top plate. Eiagonal bracings made of wood or steel provide shear (hori/ontal strength) as do panels of sheeting nailed to studs, sills and headers. citation needed
+ight5gauge metal stud framing
Hall sections usually include a bottom plate which is secured to the structure of a floor, and one, or more often two top plates that tie walls together and provide a bearing for structures above the wall. Hood or steel floor frames usually include a rim joist around the perimeter of a system of floor joists, and often include bridging material near the center of a span to prevent lateral buckling of the spanning members. ;n two5story construction, openings are left in the floor system for a stairwell, in which stair risers and treads are most often attached to squared faces cut into sloping stair stringers. citation needed ;nterior wall coverings in light5frame construction typically include wallboard, lath and plaster or decorative wood paneling.citation needed Bxterior finishes for walls and ceilings often include plywood or composite sheathing, brick or stone veneers, and various stucco finishes. !avities between studs, usually placed '=F9= cm ($9F7' in) apart, are usually filled with insulation materials, such as fiberglass batting, or cellulose filling sometimes made of recycled newsprint treated with boron additives for fire prevention and vermin control. citation needed ;n natural building, straw bales, cob and adobe may be used for both exterior and interior walls. *he part of a structural building that goes diagonally across a wall is called a *5bar. ;t stops the walls from collapsing in gusty winds. citation needed
8oofsedit Main article !oof 8oofs are usually built to provide a sloping surface intended to shed rain or snow, with slopes ranging from $ cm of rise per $& cm (less than an inch per linear foot) of rafter length, to steep slopes of more than 7 cm per cm (two feet per foot) of rafter length. - light5frame structure built mostly inside sloping walls comprising a roof is called an -5frame. 8oofs are most often citation needed covered with shingles made of asphalt, fiberglass and small gravel coating, but a wide range of materials are used. Golten tar is often used to waterproof flatter roofs, but newer materials include rubber and synthetic materials. #teel panels are popular roof coverings in some areas, preferred for their durability. #late or tile roofs offer more historic coverings for light5frame roofs. +ight5frame methods allow easy construction of unique roof designs. ip roofs, which slope toward walls on all sides and are joined at hip rafters that span from corners to a ridge. Aalleys
