• According to aftershock which happens once in a while in Bam, there is need to use springy washers in order to close all nuts and thus prevent bolts unclenching by these shakes.

Figure: sample of appropriate nuts and bolts and washer which are used in Bam steel skeletons

Figure: sample of applied nuts and bolts with washer

• Regard that only steel beams which are placed inside of the concrete must not have color cover in favor of provide more consistence while remaining structure elements must have color cover.

Figure: steel skeleton samples which sections related to concrete are not colored correctly.

• Bracing connection plates and end of each beams must be colored after final installation and wrenching unless they are not buried in concrete
• For making the process more simple, foundation bolts are covered by grease before starting pouring concrete.

Figure: bolts of column plate which are smeared with concrete due to inappropriate performance and not consideration of required provisions will prevent correct installation of steel skeleton and adjustment of column plate.

Based on what tenth subject of national building regulations provided for designing nuts and bolts of steel skeleton, there are three kind of nuts including common nuts, high resistance nuts and medium resistance nuts which have respectively resistance of 5,6 and 4,6 for common nuts and 10,9 for high resistance iron nuts and steel nuts with medium resistance by 8,8 grade in steel  skeleton. These numbers represent value of flooding stress and rupture stress of the nut. For example in 8,8 grade, first 8 is minimum final resistance of nut equals to 8000Kg, and second 8 is flooding stress in steel  skeleton equals to 8000 which it will be 6400 Kg/cm. X0.08 din standard has focus on half- screw thread din931 nut and din933 is Stud Bolt nut in nuts and bolts of steel  skeleton. These nuts can be provided by 5,6 and 8,8 and 10,9 grade and be appropriate for bearing connections in steel  skeleton. A bolt that is used in meta skeleton is recognized by din934 while din6914 is produced only with 10,9 grade which their tensile strength of these nuts is 10000 kg/cm and tensile stress is 9000 kg/cm which proved that they have high resistance in steel  skeleton and they are applied in frictional connections. It must be considered that these nuts have a few screw thread and bigger cleat implying that they are suitable for screw. Allowable bolt for these steel structures are din6915 and their washer is din6916but ASTM standard is in three kind for six corner nuts od steel skeleton which are respectively   ASTM A307, ASTM A325 and ASTM A490.

Advantageousness of steel nuts and bolts skeleton

• Construction and installation speed rather than concrete and welded structures
• High quality of structure performance
• High resistance against fire
• Using new methods of welding and cutting based on regulation og steel structures welding according to AWSD1.1

Advantages of composite roof of steel deck

• Elimination of casting
• Possibility of pouring concrete into all roofs in one time
• 20 to 30 percent saving in consuming steel of structure skeleton
• 15 to 20 percent saving in using roof concrete
• 40 percent lighter that block and beam roof and 22 percent lighter than traditional composite roof
• Least roof quake
• Reduction of foundation dimensions
• 75 percent reduction in secondary beams
• 30 percent reduction in construction cost

hangar advantageous

• Providing strength according to design need
• Possibility of avoiding innate deflects of beam sheet structures in bents
• Possibility of design and implementation of structures with very considerable dimensions
• Lighter foundation in compare to structures similar to beam sheet structures
• Considerable lightness of structure
• High security against to factors of environmental destructive such as earthquake (due to proportion of strength to high weight)
• High flexibility
• Ability of structure implementation with variable forms
• Possibility of using different materials in bent construction

High strength

Resistance of concrete and steel structures is high. Resistance rate of sections in large spans of hangar and high-rise buildings especially buildings that are located on feeble grounds is very important.
Durability

Durability of structures is acceptable and confirmed by engineering system.

Quick implementation

Foundation implementation and stiffening of building only in three days

Balanced material resistance

Steel materials are the same in pressure and tension while in shear issue they have resistance near to tension and pressure. Thus it is possible to change loads condition without destruction. It means that in conversion of compression force into tensile force nothing special happens. In reinforced concrete structures, resistance of concrete is good in pressure but it is low in tension and shear so if regions under possibility of tensile force are not reinforced, they produce crack and destruction.

Simple condition of construction and installation

Providing structure section in workshop and its installation in different conditions is enforceable with necessary provisions.

Material waste

By providing steel construction materials from our workshop, material waste is lower than providing concrete materials.

Increasing quality of construction skeleton

Increasing quality of construction skeleton causes construction of precast steel sections with high quality because of controls before, during and after structure implementation, and complete control of materials and quality control system located in construction complex from dimensional point and welding.

Complete reversibility of materials

Complete reversibility of steel structures materials provides possibility of using them again and again specially in nuts and bolts skeletons.

Hangar kinds:

• One span hangar live ˄
• A hangar with two or more spans with common column like ˄ ˄ or ˄ ˄ ˄ or ˄ ˄ ˄ ˄
• Arched hangar (in this type all rafters have certain arch)
• Full arched hangar (in this type rafters and columns both have arches)
• Polygon hangar

Since designing bent needs accurate professional work and includes important points and requirements, ignoring them leads increase of cost and decrease of economic profit while  causes irreparable incidence due to decrease of strength and stability of the structure.

Important points in bent design
Loading dead load, snow load and asymmetrical load

Lateral hangar loading including wind and earthquake

Regional coefficient, behavior and its importance in hangar implementation

Opening and length of hangar

Curtailment seam

Calculation of effective length

Percent of bent roof slope

Appropriate cover of bent roof (sandwich panel or galvanized sheet and Hexagonal wire netting

Allowable stress of soil and ground kind

Displacement control method

Designing connections and base plate for bent

Design of crane supporting beam

Design of purlin by software

Design of sag rod

Providing a design with least sheet waste

Providing pamphlet for complete calculation of hangar
design codes:

For wind force loading: Iran 519 code

For earth quack loading: Iran 2800 code

For designing steel structures: American AISC code

For designing concrete sections: Iran concrete code (Aba)

For steel structures weld: American AWS code

Construction and installation of hangar

Clearly construction and installation of bent is professional issue. It firstly sounds very easy but in fact it is very difficult. Hence, there are rare technical teams and companies that proceed for secure construction of hangar. Cutting, montage, welding and coloring (specially color type according to humid regions, bent installation (tune up and regulating hangar frames) is very critical and there is need to be accurate about on time lateral bracing of hangar because one weakness point of hangar structure is its low stability against lateral forces, while it is controlled by lateral bracing, implementation time is very important.

Controlling elements quality against local forces and stiffener appliance is a guide line for true selectin of non- prismatic sections according to hangar application including column, purlin, strut, wall post, wind bracing, sagrod, nuts and bolts and canopy.

Cutting and drilling step

Before construction of different components of hangar, by (SHOP DRAWING)^*, the sheet is cut in workshop location by guillotine and then it is montaged and welded finally required drilling are performed.

* SHOP DRAWING: they are plans that have accurate details of a column or rafter including thickness, numbers, length, width and other required characteristic for constructing section. These plans are provided from main and early plans. In order to provide mentioned plans we should be very careful because each mistake cause high cost.

Verification and color

Before coloration, elements are monitored and approved by engineers and in case of need they are sent to sand blast and they are prepared for coloration before cleansing. In this step, two or three layer are put on columns and beams and other steel elements. Number and color type are available in technical properties and plans.

Coloring is not allowed by brush and it should be performed by spray gun.

Sand blasts are operations that spray silica sand on the element with high pressure so in addition to cleansing rusting prepares surface for coloration. All steel elements are sand blast before color. Important point in sand blast operation is that excess is not allowed because causes erosion of steel layers and get thinner.

Transportation and installation

After coloration, transportation and installation are next steps in which constructed sections are transported from construction location to installation place (seller ground) and installer groups are transmitted to hangar installation place. Installation are performed by heavy cranes.

In this step we should pay attention that the frame is completely installed because in case of not installation of rafters and columns there is possibility of columns reversal due to columns height.

Steel frame system has main role in tolerating different loads including live loads, snow, earthquake, and crane loads in industrial buildings. Steel frame system is commonly composed of elements with variable sections with rigid connections. These elements are impacted by axial force, sheer force and bending anchorage.
Hangar vertical bracing

Hangar roof bracing

Hangar layers

Compression- Longitudinal elements of hangar roof

Hangar layers

Loads enforced on industrial building roofs by layers are transmitted to main inclined frames. Layers are designed and implemented in a way beams with simple spans or length equivalent to frame intervals in salon length or they are designed as consistent beams. Layers section is I form. It is recommended that maximum allowable displacement of layers by dead loads and snow load is less than spot length 200/1.

Cover of hangar roof

Z plaque of hangar

Hangar flange

In order to avoid lateral and torsional buckling, compression flange of main frame beam must keep in required intervals and along with lateral side on frame plate.

9) Hangar Anchor rod

Transverse anchor rod connects layers in certain intervals to each other. Anchor rods which implement perpendicular to layers extension to roof of inclined frame have three main functions:

• They tolerate repulsive force along with inclined surface.
• Layers prevent lateral torsional buckling of pressure flange.
• Torsional span around weak axial reduces layer side view

Due to mainly industrial application, hangar is different in design. Especially when frames are different in these structures and they are inclined while span s are larger than other structures. Due to largeness of beams and columns dimensions, existing profiles cannot be used in market and they must be made which are called sheet beam.

Design of industrial hangar

Designing hangar is a professional and very accurate job while ignoring many factors that are important in their design can be so costly hence its construction will be under questioned and it may have reverse result and weaken strength and stability of the structure. For designing a hangar following information are needed:

• Snow load and wind force on hangar
• Lateral height of hangar
• Regarded roof slop and calculation of hangar crown height
• Transverse span length of hangar
• longitudinal span length and numbers of longitudinal frames of hangar

Is crane considered as a tool in designing hangar or not?

Roof cover

By mentioned information and considered dimensions we start to design a hangar which consequently it converts into enforceable plans for construction however construction of hangar sounds simple but it is very difficult and specific engineering teams are for designing these structures. Montage, tuning up, and regulating hangar frames is very sensitive. Thus hangar lateral bracing must be implemented quickly and simultaneously because it is one drawbacks of structure stability against lateral forces however this is completely managed by lateral bracings however its implementation is very time consuming.

سالن های سوله می تواند تا دهنه حدود 60 متر تولید شود و معمولا دهنه های سالنهای مورد نیاز از 10 متر تا 25 متر با یک قاب ساده می باشد و متوسط دهنه در صنایع 20 متر وارتفاع معمول 6 متر می باشد.
مشخصات اجزا سوله
اجزا اصلی یک قاب فلزی پیش ساخته عمدتاً عبارتند از
ستون (column)
رفتر
والپست ( (wall post)
پرلین یا (z (purlin)
تیر کرین crane Beem)
میل مهار یا سگراد( agrode )
بولت (Bolt)
بادبندها : سقفی و دورتادور (Brace)
کف ستون (Base plate)
قوطی( Box)
تیر (Beem)
آبچکان
تکیه گاه جرثقیل یا براکت
مراحل اجرای پروژه سوله سازی
مراحل کلی پروژه سوله سازی پس از قبول سفارش ساخت عبارتند از :
طراحی سوله
ساخت سوله
نصب سوله
ساخت سوله
ساخت و مونتاژ تمام قطعات اسکلت فلزی در داخل کارخانه انجام می شود. ساخت شامل :برشکاری ، مونتاژ اولیه ، جوش اولیه ، مونتاژ نهایی ، جوش نهایی ، تمیزکاری و رنگ
نصب سوله

نصب اسکلت فلزی در محل مورد نظر صورت می گیرد. علاوه بر قطعات اصلی ساخته شده برخی قطعات دیگر مثل پیچ و مهره می بایستی به محل حمل شده، سپس به کمک جرثقیل و تیر و ابزار لازم عمل نصب و تنظیم نهایی صورت پذیرد.سوله به دلیل کاربرد عمدتا صنعتی از نظر طراحی با سایر سازه ها متفاوت است خصوصا آنکه قاب ها در این نوع سازه ها کاملا متفاوت بوده و دارای شیب می باشند و دهانه¬ ها نیز نسبت به سایر سازه ها بزرگتر است. به دلیل بزرگ بودن ابعاد تیرها و ستون ها، جهت اجرای این سازه نمی توان از پروفیل¬های موجود در بازار استفاده نمود و باید اقدام به ساخت آنها کرد که اصطلاحا به آن تیر ورق می¬ گویند .
مواد اولیه مورد نیاز ساخت سوله
ورق فولاد ST37 با ضخامت های 6، 8، 10، 12، 15، 20 ، 25 و 30 میلیمتر.
انواع مقاطع مختلف فولاد به شکل پروفیل مثل زد، نبشی، میله گرد، قوطی ، ناودونی و تیر آهن
انواع الکترود و سیم جوش
رنگ، ضد زنگ، حلال
انواع پیچ و مهره
بولت
روش برآورد مواد اولیه ساخت سوله
برآورد وزن الکترود سوله
در اسکلت فلزی مصرف الکترود بین 8/1 تا 5/2 در صد وزن ورق به کار رفته است و میزان 2 % به عنوان نرم به کار می رود.
محاسبه رنگ سوله
مساحت ورق مورد مصرف برای سالن های مورد نظر به شرح زیر است. در ان محاسبات سطح زد، ، نبش، پروفیل و میل گرد ها برآورد نشده بلکه فقط سطح ورق ها برآورد گردیده است. به ازای هر متر مربع به احتساب ضایعات 3/0 لیتر بر متر مربع رنگ ضد زنگ مصرف می شود و تقریبا همان میزان حلال – البته حلال برای شستشوی دست و وسائل نقاشی نیز به کار می رود.
برآورد وزن و قیمت سوله های هر پروژه به آیتم های زیر بستگی دارد
عرض یا دهانه سالن
ارتفاع سالن ( از کنار و در تاج )
طول سالن
بار برف منطقه
سایر بارها مانند جرثقیل ، طبقات داخل سالن ، سقف کاذب
مشترک بودن پایه با سوله های جانبی
سوله های صنعتی

از قابهای صنعتی به صورت یک و یا چند دهانه و عموما یک طبقه با سقف های شیبدار برای پوشش دهانه های بزرگ در کارخانه های صنعتی، کشاورزی،انبارها ، تعمیر گاهها و…. استفاده می شود.در سالهای نه چندان دور برای پوشش دهانه های بزرگ در ساختمان های مورد اشاره از سازه هایی به صورت خرپا استفاده می شد . لیکن امروزه استفاده از قابها با مقطع متغیر و اتصالات ممان گیر در ساخت سازه های صنعتی بسیار متداول است.استفاده از اعضا با مقطع متغیر در قابهای صنعتی شیب دار این امکان را فراهم می کند که در محل هایی که دارای لنگر خمشی زیادتری هستند ممان اینرسی بیشتر و در نتیجه اساس مقطع بزرگتری وجود داشته باشد سطح مقطع قابهای صنعتی عموما به شکل I هستند که در آنها ابعاد بال در طول یک عضو ثابت ولی ارتفاع جان بسته به اندتزه لنگر خمشی عضو متغیر در نظر گرفته می شود.به قابهای صنعتی با مقطع متغیر “سوله ” نیز گفته می شود که در کشور ما کارخانجات متعدد وجود دارند که قابهای صنعتی به شکل سوله را برای دهانه های گوناگون محاسبه ،طراحی واجرا می کنند .با توجه به پیشرفت فن جوشکاری بیشتر اتصالات در کارخانجات سوله سازی به صورت جوش اجرا می شود و عمدتا مونتاژ و اجرای سوله در محل مورد استفاده توسط اتصالات پیچی در نظر گرفته می شود.

طراحی اسکلت فلزی بر اساس استاندارد 519 سازمان برنامه می باشد. لذا ابعاد، دهنه، ارتفاع ، طول، بار برف، سرعت وزش باد، شیب سقف ، نوع پوشش سقف و فاصله بین قابها از عوامل تعیین کننده محاسبه می باشند. همین طور بار زنده و مرده جرثقیل و از طرفی مواد اولیه موجود یا قابل دسترس باعث برخی تغییرات در ابعاد می شود.
طراحی سوله
نقشه های اجرائی و نقشه های جزئیات و اجزا محصول در مورد اسکلت می بایستی در مورد هر قرار داد بطور جداگانه تهیه گردد و دستور ساخت صادر شود. بازرسی فنی و کنترل مرغوبیت نیز به عهده نمایندگان طراحی است.طراحی می تواند توسط افراد شرکت با کمک نرم افزار Safe، Etabsو Sap2000 صورت پذیرد و یا در برخی موارد توسط افراد متخصص و یا شرکت های مشاوره انجام گیرد. نقشه های اجرائی فونداسیون ها نیز توسط طراحان شرکت تهیه و برای اجرای آن به خریدار تحویل می گردد. – طبق استاندارد سازمان برنامه برای شیب تا 20 در صد در ایران میزان بار برف به چهار بخش تقسیم می شود: 25، 90، 150 و 200 کیلوگرم بر متر مربع. اکثریت سفارشات برای بار برف 150 کیلوگرم بر متر مربع فرض شده است. بر اساس استاندارد سازمان برنامه فشار باد در مناطق مختلف ایران تا حدود 92 کیلوگرم بر متر مربع نمایش داده شده است.

دستگاه جوش زیر پودری: جوش زیرپودری یکی از فرایند های جوشکاری قوسی است که در ان نوک الکترود داخل پودری از مواد معدنی ویژه قرار می گیرد و قوس در زیر این پودر در امتداد مسیر جوشکاری تشکیل می شود . اتصال دو فلز به یکدیگر بدون اعمال فشار بوده و ماده پر کننده از ذوب الکترود سیم جوش و یا پودر فلزی تامین می شود.