Fabrication involves operations of sawing, shearing, punching, grinding, bending, drilling and welding to the steel in order that it should be appropriate for undergoing these processes while not an impairment to its required properties. It should possess reliable and predictable strength in order that structures could also be safely designed to hold the required hundreds. The larger capability is achieved by redistribution of forces and stress in a very continuous structure, and by the contribution of the complete cross-section at yield stress to resist the applied bending.
For structural steels, these values ought to be a minimum of eighteen per cent and one. Usually, they provide all leading dimensions of the structure including alignments, levels, clearances, member size and show steelwork in associate degree assembled kind.
Sometimes, especially for buildings, connections don't seem to be indicated and must be designed by the storyteller to forces shown on the engineer's drawings requiring the submission of calculations to the engineer for approval. For major structures like bridges, the engineer's drawings typically clarify connections as well as sizes of all bolts and welds. Most example drawings of typical structures enclosed during this manual are outlined as the engineer's drawings.
Engineer's drawings deliver the goods the subsequent purposes:. Most contracts typically involve revisions at some stage thanks to the employer's amended necessities or thanks to sudden circumstances like variable ground conditions. Tags BOOK. House plan autocad House plan autocad drawing download. Staad pro manual download pdf staad pro tutorial download. College building estimation and costing estimation of a building with plan.
College building estimation and costing estimation of a building with a plan scroll down and download pdf Building Estimation Introduction This occurs because nonmetallic manganese sulphides and manganese silica inclusions which occur in steel making become extended into thin planar type elements after rolling.
In this respect the 1. In general this is not of great is sometimes used in the workshop. However, when its generic sense means the assembly of bolt, nut and large welds are made such that a fusion boundary runs appropriate washer.
Bolts in clearance holes should be used parallel to the planar inclusion, the phenomenon of lamellar except where absolute precision is necessary.
Black bolts tearing can result. Such tearing is initiated and propagated the term for an untensioned bolt in a clearance hole 2 or by the considerable contractile stress across the thickness of 3 mm larger than the bolt dependent upon diameter can the plate generated by the weld on cooling. This has a significant effect on the number of High-strength friction grip HSFG bolts should be used in different bolt lengths required. Although the new European standards have been published, their adoption by the industry has not occurred.
Bolt If bolts of different grade or type are to be used on the same manufacturers continue to produce bolts, nuts and washers project then it is wise to use different diameters. This will in compliance with the existing British standards. It is for overcome any possible errors at the erection stage and this reason that the technical information relating to prevent incorrect grades of bolt being used in the holes.
For bolting in this manual refers generally to the relevant example a typical arrangement would be: British standard. All grade 4. All grade 8. Bolt manu- and the second is one tenth of the percentage of the ratio facturers have been supplying fully threaded bolts for some of minimum yield stress to minimum ultimate stress.
The They are ordinary bolts in every respect except that the yield stress is obtained by multiplying the two figures shank is threaded for virtually its full length. For higher tensile products that a more rationalised and limited range of bolt lengths where the yield point is not clearly defined, the stress at a can be used.
It may be said that if a friction grip bolt does not the bolt ultimate strength to which it is matched, e. It is permissible to remote. The bolt remains in a state of virtually constant use a higher strength grade nut than the matching bolt tension throughout its working life. This is most useful for number and grade It nuts since grade 10 does not appear in the British Standard also ensures that nuts do not become loose with risk of bolt series. To minimise risk of thread stripping at high loads, loss during the life of the structure, thus reducing the need BS high strength friction grip bolts are matched with for continual inspection.
Mechanical properties for general grade HSFG bolts to 1. Although not normally recom- A pre-stress of approximately 70 per cent of ultimate load is mended, grade 8.
This enables shear loads to be transferred by friction between the interfaces and makes HSFG bolts may be tightened by three methods, viz: for rigid connections resistant to movement and fatigue. HSFG bolts thus possess the attributes possessed by rivets, 1 Torque control which welding and bolts displaced during the early s. It is normally fitted under the standard bolt head with the bolt via the nut thread.
On tightening, the gap The stress compounded from these two forces is at its reduces as the protrusions depress and when the specified maximum when tightening is being completed. Removal of gap usually 0. Assembly is shown in the elastic recovery of the parts causes an immediate figure 1. Figures 1. Steel is affected by atmospheric corrosion and normally requires a degree of protection, which is no problem but requires careful assessment UNDER NUT depending upon: Figure 1.
Aggressiveness of environment 1. However a typical split is shown in Table 1. Maintenance schedule Method of fabrication and erection Aesthetics. It should be remembered that for corrosion to occur air and moisture both need to be present.
Thus, permanently Table 1. Similarly the internal surfaces of Total 35 65 hollow sections do not corrode provided complete sealing is achieved to prevent continuing entry of moist air. There is a wide selection of protective systems available, and that used should adequately protect the steel at the It may be seen that the materials element comprising most economic cost. Detailing has an important influence rolled steel from the mills, bolts, welding consumables, on the life of protective treatment.
In particular details paint and so on is significant, but constitutes considerably should avoid the entrapment of moisture and dirt between less in proportion than the workmanship. This is why the profiles or elements especially for external structures.
Pro- details which allow easy and therefore less costly fabri- vided that the ends are sealed by welding, then hollow cation and erection. Minimum material content is impor- sections do not require treatment internally. For large tant in that designs should be efficient, but more relevant internally stiffened hollow members which contain internal is the correct selection of structural type and fabrication stiffening such as box girder bridges and pontoons needing details.
The use of automated fabrication methods has future inspection, it is usual to provide an internal pro- enabled economies to be made in overall costs of steel- tective treatment system. Access manholes should be work, but this can only be realised fully if details are used sealed by covers with gaskets to prevent ingress of moisture which permit tolerance see section 1.
For consuming and therefore costly rectification procedures immersed structures such as pontoons which are inacces- are avoided at site. Often if site completion is delayed then sible for maintenance, corrosion prevention by cathodic severe penalties are imposed on the steel contractor and protection may be appropriate. Adequate preparation of the steel surface is of the utmost For this reason one of the purposes of this manual is to importance before application of any protective system.
For However, articles which are larger than the bath external environments it is especially essential that all dimensions can by arrangement sometimes be gal- millscale is removed which forms when the hot surface of vanized by double-dipping. Although generally it is rolled steel reacts with air to form an oxide.
If not removed preferable to process work in a single dip, the cor- it will eventually become detached through corrosion. Blast rosion protection afforded through double-dipping is cleaning is widely used to prepare surfaces, and other no different from that provided in a single dip. Sizes processes such as hand cleaning are less effective although of articles which can be double-dipped should always acceptable in mild environments.
Various national stan- be agreed with the galvanizers. By using double- dards for the quality of surface finish achieved by blast dipping UK galvanizing companies can now handle lengths up to Paint coats are normally stepped back at 30 mm intervals, with the first coat taken 10 to 15 mm inside the joint perimeter. For non friction bolted joints the first two workshop coats should be applied to the interfaces. Where a decorative systems: or gloss finish is required then another system of overcoating must be used.
Welded members, especially overcoated. As an residual stress and may need to be straightened. Hot alternative, consideration can be given to use of dip galvanizing is especially suitable for piece-small electro-plated bolts, degreased after tightening fol- fabrications which may be vulnerable to handling lowed by etch priming and painting as for the adja- damage, such as when despatched overseas. Examples are towers or lattice girders with bolted site 3 Surfaces in contact with concrete should be free of aluminium spray give a durable coating more resis- cent surfaces.
Indicative UK maximum single dip sizes length, depth, width of assemblies are: Lifting cleats should be provided for large fabricahandling damage. In some situations it would be advisable to 7. Flush fixings e. Weld access Unsafe practice re-entrant corner 2 corners not necessary Access for welding difficult same thickness where possible Small plate quantities Fixing difficult without excessive site rework 6 thick 10 thick Uneconomic Welds may be inferior Uneconomic 8 thick taper washers Sloping or skew connection Direction change of plates Figure 1.
The number of coats given is indicative. A different number of coats may be necessary depending upon the method of application in order to comply with the dry film thickness specified. Time indicated is approximate period in years to first major maintenance. The time will be subject to variation depending upon the micro-climate around the structure.
Maintenance may need to be more frequent for decorative appearance. Standards of surface preparation quality and finish should relate to cleanliness e. No maintenance up to 12 years Minor maintenance from 12 years Major maintenance after 20 years. Environments: Location of structures.
Notes to Table 1. Usually they give all leading dimensions of the structure including alignments, levels, clearances, member size and show steelwork in an assembled form. Sometimes, especially for buildings, connections are not indicated and must be designed by the fabricator to forces shown on the engineer's drawings requiring submission of calculations to the engineer for approval.
For major structures such as bridges the engineer's drawings usually give details of connections including sizes of all bolts and welds. Most example drawings of typical structures included in this manual can be defined as engineer's drawings. Engineer's drawings achieve the following purposes: 1 Basis of engineer's cost estimate before tenders are invited. Most contracts usually involve revisions at some stage due to the employer's amended requirements or due to unexpected circumstances such as variable ground conditions.
Usually each member is shown fabricated as it will be delivered on site. Workshop drawings of members must include reference dimensions to main grid lines to facilitate cross referencing and checking.
This is difficult to undertake without the possibility of errors if members are drawn only in isolation. All extra welds or joints necessary to make up member lengths must be included on workshop drawings. Marking plans must form part of a set of workshop drawings to ensure correct assembly and to assist planning for production, site delivery and erection.
A General Arrangement drawing is often also required giving overall setting out including holding down bolt locations from which workshop drawing lengths, skews and connections have been derived. Often the engineer's drawings are inadequate for this purpose because only salient details and overall geometry will have been defined.
Workshop drawings must detail camber geometry for girders so as to counteract where required and justified dead load deflection, including the correct inclinations of bearing stiffeners.
For site welded connections the workshop drawings must include all temporary welding restraints for attachment and joint root gap dimensions allowing for predicted weld shrinkage.
Each member must be allocated a mark number. A requirement of most contracts is that work- Reference should be made to Chapter 6 Computer Aided shop drawings are submitted to the engineer for approval, Detailing for a review of the increasing use of CAD by but that the contractor remains responsible for any errors or engineers and steelwork contractors to improve their effi- omissions. Most responsible engineers nevertheless carry out ciency and minimise costly errors in their workshop fabri- a detailed check of the workshop drawings and point out any cation processes and site construction activities.
In this way any undesirable details are hopefully discovered before fabrication and the chance of error is reduced. Usually a marked copy is returned to the 1. Once approved the workshop drawings should for the design and construction of steelwork are as sum- be correctly regarded as contract drawings. In the structural Eurocodes, cer- Loading tain safety related numerical values such as partial safety factors are only indicative.
The values to be used in practice have been left to be fixed by the national authorities in each country and published in the relevant National Application Document NAD. The NAD also specifies the loading codes to be used for steel structures constructed in the UK, pending the availability of harmonised European loading information in the Eurocodes.
It also includes additional recommendations to enable the relevant Eurocode to be used for the design of structures in the UK. The relevant NAD should always be consulted for buildings to be constructed in any other country. Different design criteria may need to be applied for example in the cases of varied loadings, earthquake effects, temperature range and so on. In this manual any load capacities give are in the terms of BS ultimate strength i. They 1. The revised Part 12 published in is a Code for the design of hot rolled sections in buildings.
A guide is available26 giving member design capacities, together with those for bolts and welds. BS Part 52 deals with cold formed sections. BS uses the limit state concept in which various limiting states are considered under factored loads. The main limit states are: by Table 1. If a working load multiplied by the load factors from Table 1. As an approximation a working load can be multiplied by an averaged load factor of say 1.
The transition from BS to EC3 is inevitably a slow process and for the present, at least, both these two design standards will be used by UK designers. Ultimate limit state Serviceability limit state Strength i. It is adopted by the main UK highway and assessment of material strengths are different so that any railway bridge authorities. It has been widely accepted in capacities given in this book, where applicable to bridges, other countries and used as a model for other Codes. The should not be used other than as a rough guide.
In particular the intensity of highway loading is Part 2: Steel Bridges24 sets out the principles for the design increased to reflect the higher proportion of heavy com- of most types of steel road and railway bridges as well as mercial vehicles using UK highways since publication of the giving design rules for the steel parts of composite bridges. For the design of steel and concrete composite bridges ENV Eurocode 4: Part will provide the future design BS uses a limit state concept similar to BS Many rules.
Like building structures, the transition from BS of the strength formulae are similar but there are addi- to EC3: Part 2 and EC4: Part 2 is inevitably a slow process tional clauses dealing with, for example, longitudinally and for the present, at least, all of these design standards stiffened girders, continuous composite beams and fatigue. Present day draughting practice is a mix of traditional drawing board methods and computer aided detailing systems.
Whichever methods are used individual companies will have particular requirements suited to their own operation, but the guidance given here is intended to reflect good practice. Certain conventions such as welding symbols are established by a standard or other code and should be used wherever possible. Faint guide lines should be used and trainee detailers and engineers should be taught to practise the art of printing which, if neatly executed, increases user confidence.
Experienced detailers merely use a straight edge placed below the line when lettering. The minimum size is 2. Stencils should not be necessary but may be used for view of drawing titles which should be underlined. Underlining of other lettering should not be done except where special emphasis is required. Punctuation marks should not be used unless 2. Drawing sheet sizes should be standardised. Typical sizes used are shown in Table 2. Table 2. All drawings must contain a title block including company 2.
Dimension lines should be thin but full lines stopped just short of the detail. Dimension figures should be placed immediately above the dimension line and near its centre. The figures should be parallel to the line, arranged so that they can be read from the bottom or right hand side of the drawing. Dimensions should normally be given in millimetres and accurate to the nearest whole millimetre.
Notes should, as far as possible, all be in the notes column. Figure 2. Third angle projection should be used whenever possible 2. With this convention each view is so it in the adjacent view. A Figure 2. Scales should be noted in the title block, and not normally repeated in views. Beams, girders, columns and bracings should preferably be drawn true scale, but may excep- letter see figure 2.
The sec- When detailing columns from a floor plan two main views, A tion depth and details and other connections must be viewed from the bottom and B from the right of the plan, drawn to scale and in their correct relative positions. A must always be given.
If necessary, auxiliary views must be series of sections through a member should be to the same added to give the details on the other sides, see figure 2. Whenever possible columns should be detailed vertically on the drawing, but often it will be more efficient to draw For bracing systems, lattice girders and trusses a con- horizontally in which case the base end must be at the right venient practice is to draw the layout of the centre lines of hand side of the drawing with view A at the bottom and members to one scale and superimpose details to a larger view B at the top.
If columns are detailed vertically the scale at intersection points and connections. Auxiliary views are Holes in flanges must be dimensioned from centre-line of drawn as necessary. An example of a typical column detail web. Rolled steel angles RSA , channels, etc. When detailing a beam from a floor plan, the beam must always be viewed from the bottom or right of the plan. If a beam connects to a seating, end connections must be 2.
On columns the mark should be located on the lower end of the shaft on the flange facing north or east. On vertical bracings the mark should be located at the lower end.
Typical anchorage detail pocket and grouting information and ensure it does not damage finish or final appearance. Hand' are simply pairs or one right hand and one left hand.
A simple illustration of this is the human hand. The left hand is opposite hand to the right hand and vice-versa. Any steelwork item must always be opposite handed about a longitudinal centre or datum line and never from end to end. Erection marks are usually placed at the east or north end of an item and opposite handing does not alter this.
The erection mark must stay in the position shown on the drawing, i. If to be left in place, they shall be positioned such that they are totally enclosed by 30 mm minimum grout cover. The spaces to be grouted shall be clear of all debris and free water. It shall be placed by approved means such that the spaces around HD bolts and beneath the baseplate are completely filled. In particular cases it bolts shall be of sufficient size and strength.
They shall may be necessary to draw weld cross sections to enlarged be designed so that they prevent pull-out failure. The scale showing butt weld edge preparations such as for concrete into which HD bolts are anchored shall be complex joints including cruciform type. Usual practice is reinforced with sufficient overlap and anchorage for workshop butt weld preparations to be shown on sepa- length so that uplift forces are properly transmitted.
Site welds should be detailed on drawings with the dimensions taking into account allowances for weld 2. Space should be allowed around the weld It is economic to use abbreviations in using space eco- whenever possible so as to allow downhand welding to be nomically on drawings. A list of suitable abbreviations is used. Load capacities for total reaction from 2 incom- members are contained in the Design Guide to BS ing beams sharing the same and from other literature as given in the Further Reading.
Capacities of bolts and welds to BS are included in Tables 3. The capacities must be compared with factored loads to BS The tables indicate whether bolt shear, a To a perimeter column size 6 6 97 UC, of grade S steel via its flange.
The range of coverage sided connection with another beam having the same is listed at the foot of this page. Capacity cannot be increased by thicker webbed beam because bolt shear governs because value is not in italics.
So try grade 8. These capacities must be compared with factored loads to BS Baseplate thickness is derived to BS clause 4.
From Table 3. N8 type using grade 8. Worked example Question The following example illustrates use of Table 3. A 6 6 97 UC column carries a factored vertical From Table 3. Select a baseplate size.
Table 3. See figure 3. X 50 nom. Thickness mm Shear at 0. The dimensional information on standard sections is given by permission of Corus pre- s m d1 d e viously British Steel. These sections are widely used in d2 many other countries. All plated to BS Part 1. Ordering example Bolts M24 size 80 mm long, grade 8. With standard nut grade 8. All cadmium plated. It is permissible to use a higher strength grade nut than the matching bolt number.
Grade Bolt length l normally available in 5 mm increments up to mm length and 10 mm increments thereafter. Notes to Table 4. BS covers black bolts of grades 4. BS covers precision bolts in grades 4. Tolerances are closer and the maximum dimensions here quoted are slightly reduced. Sizes M16, M20, M24 and M27 up to This may be required where the design does not allow the threaded portions across a shear plane.
Bolt length l normally available in 5 mm increments up to 80 mm length and in 10 mm increments thereafter. Commonly used sizes are underlined. Non-preferred sizes shown in brackets. Preferred larger diameters are M42, M56 and M D 2 d to the nearest 2 mm above. To BS Table 4. Root d Distance 2 2. Minimum desirable pitch for HSFG bolts based on 2 mm clearance between socket and bolt head. See figure illustrating face clearances.
The deflections on the larger spans should be checked and stiffeners used if found to be necessary. Extreme fibre stress : The above safe loads include the weight of the plate.
To avoid excessive deflection, stiffeners should be used for spans over 1. Other specifications by arrangement. Lengths up to 10, mm can be supplied for plate 6 mm thick and over.
M12 40 mm min. H min. Double V ground flat 8 Double V partial pen. Weld preparations should not be detailed on engineers drawings but are required on workshop drawings.
L 2 mm max. For an exact width in a band eg mm in to mm please refer for precise length available if required. Notes 1. Not available Typical Qualities These show the principles of some of the types of see Further Reading, Design, 10 , 11 and 12 produced connection commonly used. A typical workshop drawing of a roof lattice These books provide details of standardised simple and girder is included in figures 5.
Frame must be erected braced. All welds 6 fillet both sides of all joints UOS. All hollow sections to be sealed by welding.
All bolts M20 4. All holes 22 dia. Figure 5. For fabrication works with templating facility this detail not necessary. UB UB sealant sealant screed screed 75 min. Civil and structural engineers were one of the first groups to make use of computers. The ability to harness the In the early days much computer draughting development computer's vast power of arithmetic made matrix methods was undertaken by large companies who produced and of structural analysis a practical proposition.
Virtually no early beginning a whole range of computer programs and interaction could take place between these individual associated software have been developed to deal with most systems, principally due to the inconsistent computer lan- aspects of analysis and design. In the early days the use of guage adopted by each company. Also most of these sys- the computer to produce drawings, while possible, did not tems were driven by the company's mainframe computer receive much widespread attention.
But now the use of which lacked sufficient memory, and because other soft- computers for design and draughting can be said to have ware was used alongside accounts, purchasing, etc. Computer draughting systems have been available as commercial products since the s.
Most of the early With the evolution of the PC from a non-graphical low spec systems were developed by the electronics industry to computer to the modern high-speed graphics workstation meet its own needs in the production of printed and inte- the power and the capabilities have developed to put very grated circuits.
To the civil and structural engineer these sophisticated tools in the hands of the detailer. However, they formed the basis for the subsequent developments of systems more suited to construction. Within a steel struc- The use of the computer to produce drawings differs in ture, connections will often comprise several intersecting many ways from its use in analysis, design and other members, originating from any number of different direc- numeric activities, and computer draughting is sub- tions.
The tasks of resolving such geometry into sound stantially different from the traditional manual method. The equipment now used typically consists of a visual dis- Traditionally, skilled draughtsmen with many years of play unit or monitor and the computer processor drive detailing experience have been required. A keyboard and mouse complete the equipment. Add-on peri- The constructional steelwork industry has experienced pherals might include plotters and scanners.
While the enormous economic and technological upheavals in recent input to and output from a draughting system are in years. In order to remain competitive, steelwork con- graphical form, the computer's own representation of a tractors have turned to new technologies in order to drawing is as a mathematical model. The steelwork structure is modelled in 3-D, steelwork fabricators.
The draughtsman does not in fact draw, instead he models. In building design, the principal means of communicating However, he is still a draughtsman, as the 3-D modelling design intent is the drawing, whether it is a sketch, a system is his new tool and it will require his input and concept design or a construction document.
The tradi- detailing knowledge. Each item is detailed independently steelwork, bolts, welds, etc. It may contain any information whatso- elements fit together. It is difficult to standardise details ever about any element within the structure. The steel on a contract divided between several draughtsmen. All structure actually exists, perfectly to scale, inside the material lists, bolt lists and computer numerical control computer.
At any stage of the construction of the 3-D CNC programs must be produced manually by interpret- model, detailed drawings, listings or any other information ing the detailed drawings. There are many potential may be produced completely automatically by the system. Once created, the database of information can be utilised by other parts of the software, to generate data in different The first CAD systems were effectively electronic drawing ways such as detail drawings, general arrangements, boards, allowing the user to create lines, circles, text and materials lists, numerical control NC data, etc.
The dimensions which duplicated the manual process, with the steelwork contractor knows that if the data i. In 2-D is correct, then all the subsequent data will also be correct, CAD, basic facilities such as move, copy, rotate, delete, so there is no need to check the drawings for dimensional etc. Some 2-D CAD accuracy. The 3-D model is the central source of all infor- systems may have several parametric routines and libraries mation, as shown in figure 6.
These will assist the manual detailing process and enable better standardisation. However, each item is still detailed independently and will generally require the same substantial checking as manual draughting.
Most packages now have some sort of graphi- material requirements estimating crude 3-D model commercial 3-D drawings, drawings,G. The fabricator can then use the resultant steel model with the detailed model returned to the standard steel connection library — macros structural analysis member design packages detailed 3-D model interactive modelling for non-standard connection details engineer for checking and monitoring purposes.
The relative ease of use and cost-effectiveness of 2-D systems means that they are still a valid solution, particularly for alldrawings drawings—-G.
In addition to the All steelwork structures are created within a 3-D frame- required to be carried out on the member, for example work of vertical grids and horizontal datum levels. The cutting a member to a plane such as a rafter to the face of draughtsman will input these into the 3-D model, in a stanchion or cutting out parts of members to create accordance with the architect's or consulting engineer's openings or notches.
The draughtsman must be able to general arrangement drawings. In The sizes of the principal members in a structure will addition, it must be possible to save interactively modelled generally have been determined by an engineer. In addi- details to a library, so that they may be reused on any tion, end reactions are often supplied to the fabricator for particular contract.
There are generally two levels in this hierarchy. The supplied. This can have significant benefits with com- planning of fabrication and delivery to site; it could be a plicated setting-out problems. And if you have any technical questions about structural steel design or construction, be sure to contact the AISC Steel Solutions Center.
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