Rebar arrangement and construction carryout

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Rebar arrangement and construction carryout

  1. 1. Section 1 REBAR ARRANGEMENT &CONSTRUCTION CARRYOUT
  2. 2. 1. Understanding of Drawing1) Examination of drawing When construction contract is completed, the contents of the drawings are surveyed and checked before construction work. Although it is a rule to survey the drawings right from the 1st page, it is common to check the scale and the number of floors of the building and then plan, elevation, exterior appearance, lines and windows of the building . Not only orientation, precautions and specifications, but front elevation, rear side elevation, right side elevation, left side elevation, partial development, partial section, and detail section, etc should be also looked over to be reminded in the construction site. As construction work progresses , present work should be checked and compared with instructions on the drawings , and an entire understanding of drawings should be preceded before the next step. Plan, structural plan, foundation, section, etc are checked if there is any suspicious portion because all the drawings are not made by only 1 person. There is also necessity of discussion when there is any question or changes in the work. In order to make smooth and steady progress of the work, a lot of time and repeated practice are required. In case of small scale of construction , it is progressed from the ground to the upper floor in general , however there is no determined rule.
  3. 3. As construction work is not a simple one but rather complicated, it is difficult orimpossible to explain all of the construction methods satisfactorily in written or spokenwords alone. Clear understanding of basic knowledge is quite helpful. Plan of reinforcement should be drawn before reinforcement , however , when thescale of construction is large , plan of reinforcement is given in advance or shopreinforcement are also available . Although the trend has been to increase the usage of shop reinforcement for thesmooth progress in the crowded city , field reinforcement is explained in this book dueto the necessity of prompt applications in the field and its convenience. Every reinforcement has its own rule , however it could be changed when necessaryunder the permission of supervisor. For example , hooks at the tip of stirrup could be changed from Figure 1 to Figure 2. Figure 1 Figure 2
  4. 4. 2)What is drawing? Drawings are used in every industrial field with the development of industries. Although their types and applications are different, there are agreed rules that are called IPC(International Graphic Code), accepted by everyone in each field. Specified rules and standards with reference to symbols, numbers, lines and letters are adapted to drawings to help everyone understand what they mean. When one begins to construct a building, one should carefully consider the implications of drawings. In this book, plan of reinforcement is briefed to help the workers understand them more easily. Drawings of construction work are grouped roughly as civil engineering and architecture. Although there are some differences, all the contents could be understood since they are all in accordance with IPC mentioned above.3) Classification of drawing Shop Drawing Drawings that suggest overall dimensions of each member with symbols, numbers and lines for the construction work Detailed Drawing Detailed drawings that describe shapes , types and dimensions of each element for the bar-fabrication
  5. 5. Understanding of DrawingDrawings are in their own sequence beginning with the title and contents on the 1stpage.Structure drawing of Rebar is for this case.There are several types of drawings which include machinery, electricity,sanitation, fire protection, communication, etc according to the type of work andthere are details as follows.A) Construction i. Building layout ii. Elevation iii. Plane figure iv. Cross Section v. Part Detailed drawingB) Structure i. Drawing of column center ii. Plane figure of structure iii. Drawing of stairway and slab rebar arrangement iv. List of pillar , beam and retaining walls v. Detailed drawing of rahmen rebar arrangementC) In general, the order of drawing is in a sequence mentioned above, and all the drawings are in scale.Scale (All the units in "mm")Among several types of rulers used in drawings, scale is indispensable.There are many types of scale. Among them 300mm scale is frequently used.It has carved line in the middle of each side, colored red, blue and black todistinguish its scale.Scale in red ,
  6. 6. Scale in blue , Blue Red Scale in black , Black Other different scales are available like ,4) Usage of symbol General symbol Description Symbol Indication Symbol Length L Distance of Rebar Rebar indication Diameter of Rebar High density Area A No. of Rebar No. of cross section Volume V Part cross section No. of drawing (Civil engineering, Architecture, Structure) Radius R No. of cross section Part detailed No. of drawing drawing (Civil engineering, Architecture, Structure) Main entrance Level EL. 0.0000 Sub entrance indication(Plane) Level indication Scale S 1/200 (elevation, cross EL. 0.0000 section) Finish No of layer & Serial No. of Member Member Symbol per part of structure Structural plane No. per layer
  7. 7. Drawing SymbolSymbol Description Symbol Description B Bottom T Top N.F. Near Face F.F. Far Face E.F. Each Face E.W. Each way B.O.F Bottom of Foundation T.O.C Top of Concrete T.O.F Top of Foundation E.J. Expansion Joint Ab Size of a rebar( ) C.J. Construction Joint fck Strength of Concrete(kgf/ ) fy Resistance strength of rebar(kgf/ ) Compression strength of concrete per Available resistance power of fcu(t) fe date(kgf/ ) ground(tonf/ ) Nominal diameter of deformed Available resistance power per D(db) Fp rebar(mm) pile(tonf/ ) C L Center Line & And H Height @ Distance THK. Thickness W WidthCONC. Concrete TYP. Typical N.T.S Not to Scale ST’L Steel EL. Elevation Level FL. Floor Level
  8. 8. 2. Characteristic of Rebar Throughout the reinforcement work, reinforcing bar strongly bonds to mixed concrete and this makes floor, wall and other members very strong. In other words, reinforcement is a bar that is embedded in the mixed concrete to make a member strong. Bar and concrete have low thermal expansion coefficients, 1 10-5 , and therefore have little thermal deformation or failure, cooperatively strengthening members.1) Production process of rebar Ingot : made from melted iron ore and pig iron Billet : made from hot-rolled ingot Reinforcing bar : manufactured per type by hot-roll process from the purchased billet Type Symbol Resistance Point (kgf/mm2) Classification SD 30A over 30 Green(D:General type) SD 30B 30 ~ 40 White(D:General type) Deformed SD 35 35 ~ 45 Red(HD:Density type) Rebar SD 40 40 ~ 52 Yellow(HD:Density type) SD 50 50 ~ 64 Black(HD:Density type) p.s.) KS Symbol of Deformed Rebar : indicate as SD300, SD350, SD400, SD500 In SD400, S is steel, D is Deformed Bar, 40 indicates that resistance point is over 40kgf/mm2(=400N/mm2=4,000kgf/cm2).
  9. 9. 2) Classification of rebar Regular bars : The length of one strip is 8,000mm by KS(Korean Standard). Each bundle has almost same weight. (basis of 1-2 ton) Irregular bars : Irregular bars that are made of leftovers or nonuniform bars. Reinforcing bars that are mainly used in the construction site are SD40 high strength steel and SD30A mild steel, Each bar is colored yellow(HD) and green(D) respectively in order to identify them. Mild steel usually used as processed goods such as hoop , stirrup , etc. Type Symbol Classification SD 30A Green(D) Deformed SD 40 Yellow(HD) Bar SD 50 Black p.s.) SD:Steel Deformed3) Type & Weight of rebar If the worker in the construction site prepare the bars more than needed, there might be rust on the surface of the rebar. To prevent oxidation of the bar, it is advised to prepare moderate amount of the bars. When you need to pile the bars near the construction site, they should be classified and piled on the big gravels to make the ventilation easy. And also cover the stocked bars to avoid humidity. There are usually two types of deformed steel used in the construction work. SD30A(mild bar) - normal strength bar, has green-colored end SD 40(high tension bar) - high strength bar, has yellow-colored end
  10. 10. Size, Weight of Deformed Bar(8m) (KS D3504) Content 1tonf 2tonf nominal diameter Per each Per meter 1tonf 2tonf Type Q’ty per Q’ty per (D)mm (kgf) (kgf) (kgf) (kgf) HD10 210 420 9.53 4.48 0. 56 941 1,882 HD13 120 240 12.7 7.96 0.995 955 1,910 HD16 75 150 15.9 12.48 1.56 936 1,872 HD19 56 112 19.1 18 2.25 1,008 2,016 HD22 41 82 22.2 24.32 3.04 997 1,994 HD25 32 64 25.4 31.84 3.98 1,019 2,038 HD29 25 50 28.6 40.32 5.04 1,008 2,016 HD32 20 40 31.8 49.84 6.23 997 1,9944) Weight limit of rebar Weight limit Size of Rebar Remark 1 each 1 ton Less Than D10 - 0.8% 7.0% Sampling of test piece and D10 ~ D16 6.0% 5.0% calculation of weight limit D16 ~ D29 5.0% 4.0% should be in accordance with KS D3504 More Than D29 4.0% 3.5%
  11. 11. 3. Calculation for unit weight of Rebar1) Unit weight Unit weight is the weight of bar per 1m. FYI, the basic value in drawing and the length of rebar is “mm”. When calculating unit weight, you must convert into “m” from “mm”. Unit weight per rebar type Rebar Size Unit Weight Rebar Size Unit Weight HD10 0.56 f/m HD25 3.98 f/m HD13 0.995 f/m HD29 5.04 f/m HD16 1.56 f/m HD32 6.23 f/m HD19 2.25 f/m HD35 7.51 f/m HD22 3.04 f/m HD38 8.95 f/m Basic unit conversion 1ton = 1,000kgf 1kgf = 1,000gf 1m = 100cm 1cm = 10mm2) Calculation of length(L) in model
  12. 12. 4. Criterion of Rebar arrangement1) Rebar coating It means the shortest distance to the surface of concrete to cover rebar surface. Rebar coating thickness of each part must be considered in the period of plan after considering durability, refractory, safety in structure endurance & errors in construction carry-out. There are examples of coating case as ground criterion for all construction without segmenting the case of ground and also the case of foundation regularly. By the effect of CO2, humidity, acid gas, there will be going on of neutralization step by step from the surface of concrete. If the coating is small, its speed to arrive rebar will be faster . If so, the rust will expand, the adhesion of concrete coating will drop, white phenomenon will exist, senility of structure body will facilitate. (Unit:mm) Rebar Size Minimum Classification coating/thickness Remark Concrete pouring under water Foundation All rebar 100 Concrete burying under ground forever Foundation All rebar 80 after land pouring concrete adjoined Wall, pillar over HD29 60 Concrete part to expose to outdoor Beam (outside exposure below HD25 50 air and to adjoin land directly beam) Slab(foundation slab) below HD16 40 over HD35 40 Slab, Wall, Under Flooring below HD35 20 Concrete part not to adjoin land and Tiehoop outdoor air Beam, Pillar Stirrup 40 Spiral rebar Shell, Member All rebar 20 Note : “direct exposure to the air of outdoor” means the case of direct exposure of climate change and humidity change.
  13. 13. < Independent < Pile < Pillar > foundation > foundation > Coating thickness 80 Coating Hoop Coatingthickness 80 thickness 50 Cushion Coating Lean Concrete thickness 40 Lean Concrete < Beam > < Wall & Slab > Coating thickness 20 Wall Stirrup Coating Slab thickness Coating thickness In Shear wall, the arrangement of rebar should be to the inside of vertical rebar. Regarding wall, horizontal rebar should be arranged to the outside of vertical rebar. Regarding outside wall in underground which compressed by the land, more arranged rebar should be arranged to the outside after comparing the arrangement quantity between vertical rebar and horizontal rebar.
  14. 14. 2) Rebar distance Classification Net Distance Distance Over 1.5 times of nominal diameter Deformed Over 1.25 times of max. size of thick aggregate. rebar Net distance Over high value in 25mm3) Type of tying Regarding the working of tying , there are folded tying(lap splice) , compressed tying(welded splice) , mechanical spiral tying(mechanical splice). But compressed tying(welded splice) , mechanical spiral tying(mechanical splice) have to be effected over 125% of resistance strength(fy) in plan criterion. Folded tying (lap splice) It is tying method to fold the fixed length from end part to new tying part by using regular rope currently.
  15. 15. Folded tying(lap splice) The value in ( ) is the case of upper part rebar. Concrete Tying length of deformed rebar to be Tying length Rebar Rebar extended of deformed Strength Type Size rebar to be (kgf/Cm2) A Class Tying A Class Tying compressed Under D19 31.5d (41.0d) 41.0d (53.3d) 210 Over D22 39.3d (51.1d) 51.1d (66.4d) SD30 Under D19 29.4d (38.2d) 38.2d (49.7d) 240 21.6d(fy=3,000 ) Over D22 36.8d (47.8d) 47.8d (62.2d) Under D19 27.8d (36.1d) 36.1d (47.0d) 270 Over D22 34.7d (45.1d) 45.1d (58.6d) Under HD19 42.0d (54.6d) 54.6d (71.0d) 210 Over HD22 52.4d (68.1d) 68.1d (88.5d) SD40 Under HD19 39.2d (51.0d) 51.0d (66.2d) 240 28.8d(fy=4,000 ) Over HD22 49.1d (63.8d) 63.8d (83.0d) Under HD19 37.0d (48.1d) 48.1d (62.5d) 270 Over HD22 46.3d (60.2d) 60.2d (78.2d) 1. The length of folded tying of rebars which have different diameter must over high value between the fixed length of high diameter rebar and the folded tying length of low diameter rebar . 2. The tying position must be placed to low stress / to compressed stress of concrete. 3. By the criterion of concrete structure plan , it is mentioned that it is available for folded tying in case of D29~D35 rebar. However, you have to check in advance the problem such as the net distance of rebar is not secured and also the tying length will be exaggerated if you apply folded tying of thick rebar. Generally, there are more advantageous case by using mechanical tying instead of folded tying in case of over D29 rebar. A class tying : must be zigzag(rotation) tying arrangement and arranged rebar quantity is over 2 times of required rebar quantity which defined in total block of tying part and also under 50% of rebar tying quantity within required folded length. B class tying : it is available for the tying of anti-earthquake plan and generally it is applicable to all construction site. Regarding SD500 , you must apply 1.25times of B class tying. Regarding beam main bar tying , you must apply B class tying if you dont mention tying position specially. But, you can apply A class tying if you want to tying the compressed part of concrete. (the compressed part of concrete : upper part main bar places near center part of span, lower part main bar places near pillar)
  16. 16. The tying length of wall vertical length is available around 40db of under HD19 especially.Example of folded tying(lab splice) Folded tying of vertical rebar in case the distance of rebar arrangement is different Tying Length of Tension bar(Ls) Tying Length of Tension bar(Ls) Slab upper Slab upper part part Fixed length of Tension bar Vertical Wall rebar S : Distance of Rebar Ls : Tying length of Tension bar Folded tying of horizontal rebar Example) Length of folded tying to be extended of vertical & horizontal rebar Diameter Length Tying Length of Tension bar(Ls)
  17. 17. Compressed tying(welded splice)It is the tying method to compress through heat-treatment end to end by usingmachinery.As shown in figure(A) , place 2 bars 3mm away , heat up both of the ends by usingmechanical equipment and add pressure to weld splice them figure(B), usuallyavailable for all bars.Mechanical spiral tying(mechanical splice).As the mechanical splice method , it is rebar tying method to connect the spiralpart with nut & coupling by cutting screw by expanding the end of rebar over theregular size. (A) Connect Nut (C) Move Coupler (B) Connect Coupler (D) Move Nut
  18. 18. 4) Fixing and tying In order to effect the adequate resistance strength of rebar, it is essential to obtain the enough adhesion strength with concrete. The more you increase the net distance & coating thickness of rebar, the larger of adhesion strength. Fixing length is the buried length in concrete to effect the adequate resistance strength of rebar and fix the length with the criterion of max. stress point of appropriate rebar. The fixing and tying length of rebar is changing by the strength of material and type of rebar arrangement , etc. i. It will be lengthen by using HD(high density) rebar.(SD40 is 1.33times of SD30A) ii. It will be shorten by using HD concrete.(inverse proportion from square root of concrete strength) iii. It will be shorten if net distance and coating thickness of rebar increase. iv. It will be shorten by the restriction effect if it is surrounded by stirrup and tie hoop. Caution : If the fixing and tying length of rebar will be shorten , the resistance strength of rebar will be reduced as long as the shortened length. Also, in case the heavy binding of splice part of rebar needlessly sometimes, binding has only the role to prevent the movement of rebar when pouring concrete and also no relation to adhesion strength of rebar. (the tensile of a D25 rebar is 5.04 4.0=20.16tonf) If the position of extended rebar for the tying of poured concrete is wrong, it is available for bending of splice with the angle of under if error is trivial but you need to take additional action to increase the section of additional material if error is over that angle. In case slab or wall rebar will be cutted by temporary exit such as material pick-up exit, etc, you must extend the rebar which is over the length of splice to both ends of exit. If width of exit is narrow or the length of rebar extended is shorten , the length of splice will be shorten when pouring exit concrete later.
  19. 19. Calculation of bar length What should be added to original length : splice length, fixed length Splice length : extra length to lap the bars Splice length Fixed length Fixed length : developed length when the bar is fixed Method to calculate fixed length Fixed length of rebar which has fixed length of 90 Standard hook standard hook tension bar fixed length of tension bar- In case of fixing to neighbor beam - - In case of fixing to end pillar - Tension bar and compression bar tension bar : The main usage is tension bar because rebar is reinforced material to reinforce the tension of weak point of concrete. compression bar : the rebar to be arranged in addition to increase the resistance strength in concrete material and it is mainly applicable to the pillar of high building to cover the compression. Refer to the diagram (#22 page) for tying & fixing per rebar diameter Compression Tension
  20. 20. 5) Form of fixed beam When arranging beam, the marked on drawing as bending bar is mainly Japanese method of rebar arrangement. Our standard will be cut-bar instead of bending bar(Japanese method) . The length to extend to reverse side from max. Stress point of fixed length. Hook should place over the center of pillar. Fixed length is fixed length of tension upper bar. In case of fixing with standard hook, fixed length of rebar which has standard hook will be applied. If not, fixed length of tension bar will be applied. is generally fixed length of lower compression bar and it is available of fixation if it is extended to pillar over 15cm without hook.
  21. 21. 6) Example of fixed length per rebar diameter Fixed length of tensile rebar Fixed length of tensile rebar in slab(SD 400) (unit:mm) Str en 24N/ 27N/ 30N/ 35N/ 40N/ Remark gth Rebar 240kgf/ 270kgf/ 300kgf/ 350kgf/ 400kgf/ 300 300 300 300 300 400 380 360 330 310 540 510 490 450 420 730 680 650 600 560 When using SD500 rebar(fy=500N/ =5,000kgf/ ), apply 1.25 times Fixed length of tensile rebar in foundation, pillar, beam, wall(SD400) (unit:mm) 24N/ 27N/ 30N/ 35N/ 40N/ St re 240kgf/ 270kgf/ 300kgf/ 350kgf/ 400kgf/ ng th Rebar General bar Upper bar General bar Upper bar General bar Upper bar General bar Upper bar General bar Upper bar HD10 400 510 370 490 360 460 330 430 310 400 HD13 510 670 490 630 460 600 430 550 400 520 HD16 630 820 600 770 570 730 520 680 490 640 HD19 750 970 710 920 670 870 620 810 580 760 HD22 1080 1410 1020 1330 970 1260 900 1170 840 1090 HD25 1230 1600 1160 1510 1100 1430 1020 1320 950 1240 HD29 1430 1850 1350 1750 1280 1660 1180 1540 1110 1440 HD32 1570 2050 1480 1930 1410 1830 1300 1690 1220 1590 When using SD500 rebar(fy=500N/ =5,000kgf/ ), apply 1.25 times
  22. 22. Fixed length of compression bar Fixed length of compression bar(SD400) (unit:mm) Str en 24N/ 27N/ 30N/ 35N/ 40N/ 50N/ gt Rebar h 240kgf/ 270kgf/ 300kgf/ 350kgf/ 400kgf/ 500kgf/ HD10 210 200 200 200 200 200 HD13 270 260 240 230 210 210 HD16 340 300 300 280 260 260 HD19 400 370 360 330 310 310 HD22 460 430 410 380 360 360 HD25 520 490 460 430 400 400 HD29 600 570 540 500 470 470 HD32 670 630 600 550 520 520 When using SD500 rebar(fy=500N/ =5,000kgf/ ), apply 1.25 times7) Example of splice length per rebar diameter 1) Classification of tension splice A class tying : must be zigzag(rotation) tying arrangement and arranged rebar quantity is over 2 times of required rebar quantity which defined in total block of tying part and also under 50% of rebar tying quantity within required folded length. B class tying : it is available for the tying of anti-earthquake plan and generally it is applicable to all construction site. Actual arranged rebar requirement Max. splice % within folded splice length Required rebar Q’ty 50% 50% 2 2 2) Upper bar : horizontal rebar without concrete harded over 300mm under splice part and fixed length 3) The rebar with folded splice without contacting directly each other in bending material must not depart over little value between 150mm or 1/5 of folded splice length.
  23. 23. A class splice length of tension rebarSplice length of slab(SD400) (unit:mm) Str en 24N/ 27N/ 30N/ 35N/ 40N/ Remark gthRebar 240kgf/ 270kgf/ 300kgf/ 350kgf/ 400kgf/ HD10 300 300 300 300 300 HD13 400 380 360 330 310 HD16 540 510 490 450 420 HD19 730 680 650 600 560 When using SD500 rebar(fy=500N/ =5,000kgf/ ), apply 1.25 timesA class splice length of foundation, pillar, beam, wall(SD400) (unit:mm) St 24N/ 27N/ 30N/ 35N/ 40N/ ren gth 240kgf/ 270kgf/ 300kgf/ 350kgf/ 400kgf/Rebar General bar Upper bar General bar Upper bar General bar Upper bar General bar Upper bar General bar Upper bar HD10 400 510 370 490 360 460 330 430 310 400 HD13 510 670 490 630 460 600 430 550 400 520 HD16 630 820 600 770 570 730 520 680 490 640 HD19 750 970 710 920 670 870 620 810 580 760 HD22 1080 1410 1020 1330 970 1260 900 1170 840 1090 HD25 1230 1600 1160 1510 1100 1430 1020 1320 950 1240 HD29 1430 1850 1350 1750 1280 1660 1180 1540 1110 1440 HD32 1570 2050 1480 1930 1410 1830 1300 1690 1220 1590 When using SD500 rebar(fy=500N/ =5,000kgf/ ), apply 1.25 times B class splice length of tension rebar It is available for the tying of anti-earthquake plan and generally it is applicable to all construction sites.B class splice length of slab(SD400) (unit:mm) Str en 24N/ 27N/ 30N/ 35N/ 40N/ Remark gtRebar h 240kgf/ 270kgf/ 300kgf/ 350kgf/ 400kgf/ HD10 390 390 390 390 390 HD13 520 490 470 430 410 HD16 700 660 630 580 550 HD19 940 890 840 780 730 When using SD500 rebar(fy=500N/ =5,000kgf/ ), apply 1.25 times
  24. 24. B class splice length of foundation, pillar, beam, wall(SD400) (unit:mm) St 24N/ 27N/ 30N/ 35N/ 40N/ ren gth 240kgf/ 270kgf/ 300kgf/ 350kgf/ 400kgf/Rebar General bar Upper bar General bar Upper bar General bar Upper bar General bar Upper bar General bar Upper bar HD10 510 670 490 630 460 600 430 550 400 520 HD13 670 870 630 820 600 780 550 720 520 670 HD16 820 1070 770 1000 730 950 680 880 640 830 HD19 970 1260 920 1190 870 1130 810 1050 760 980 HD22 1410 1830 1330 1720 1260 1640 1170 1510 1090 1420 HD25 1600 2080 1510 1960 1430 1860 1320 1720 1240 1610 HD29 1850 2410 1750 2270 1660 2150 1540 2000 1440 1870 HD32 using SD500 rebar(fy=500N/ When 2050 2650 1930 2510 =5,000kgf/ ), apply 1.25 times1590 1830 2380 1690 2200 2060 Splice length of compression rebarStrength fck = 21N/ = 70N/ (210kgf/ - 700kgf/ ) Rebar SD400 (fy=400N/ =4,000kgf/ ) SD500 (fy=500N/ =5,000kgf/ ) HD10 300 410 HD13 380 540 HD16 470 660 HD19 550 780 HD22 640 910 HD25 720 1030 HD29 840 1190 HD32 930 1320
  25. 25. Fixed length of tension bar which has standard hook fy=400N/ (4,000kgf/ ) fixed length of tension bar (diameter) tension (diameter) mindestroyed section of concrete tension 3db HD10 ~ HD25 or 4db HD29 ~ HD35 5db over HD38 Str en 24N/ 27N/ 30N/ 35N/ 40N/ 50N/ gt Rebar h 240kgf/ 270kgf/ 300kgf/ 350kgf/ 400kgf/ 500kgf/ HD10 210 200 200 200 200 200 HD13 270 260 240 230 210 210 HD16 340 300 300 280 260 260 HD19 400 370 360 330 310 310 HD22 460 430 410 380 360 360 HD25 520 490 460 430 400 400 HD29 600 570 540 500 470 470 HD32 670 630 600 550 520 520 When using SD500 rebar(fy=500N/ =5,000kgf/ ), apply 1.25 times. Fixed length and splice length of binded rebars. Increase the fixed length and splice length of binded rebars as follows. a) 3pcs binded rebars : increase 20% b) 4pcs binded rebars : increase 33% The splice of each rebar must not duplicated
  26. 26. 5. Criterion of Rebar bend-processing1) Bending of main bar and leftover length (unit:mm) fixed roller center pole fixed roller center pole Drawing (over 12d) (4d or over 60mm) Rebar Roller min. radius Leftover length Rebar size diameter Condition A Condition B Condition C HD10 9.53 30 120 60 HD13 12.7 3d 40 160 60 HD16 15.9 50 190 70 HD19 19.1 60 230 80 12d 4d HD22 22.2 3d 70 270 90 HD25 25.4 80 310 110 HD29 28.6 120 350 120 4d HD32 31.8 130 390 130
  27. 27. 2) Bending of stirrup, hoop and leftover length (unit:mm) fixed roller center pole fixed roller center pole Drawing Rebar Roller min. radius Leftover length Rebar size diameter Condition A Condition B Condition C HD10 9.53 20 60 60 HD13 12.7 2d 30 6d 80 80 HD16 15.9 35 100 6d 100 or HD19 19.1 60 120 60mm 120 HD22 22.2 3d 70 12d 280 140 HD25 25.4 80 320 1603) Rebar processing form Rebar s hook(one-side, both-sides) one-side both-sides
  28. 28. U type Closed typeTransformational closed type
  29. 29. 4) Slope dimension of rebar processing(hunch) 100 140 120 370 520 430 640 910 740 910 1290 1050 110 160 130 380 540 440 650 920 750 920 1300 1060 120 170 140 390 550 450 660 930 760 930 1320 1070 130 180 150 400 570 460 670 950 770 940 1330 1090 140 200 160 410 580 470 680 960 790 950 1340 1100 150 210 170 420 590 490 690 980 800 960 1360 1110 160 230 190 430 610 500 700 990 810 970 1370 1120 170 240 200 440 620 510 710 1000 820 980 1390 1130 180 260 210 450 640 520 720 1020 830 990 1400 1140 190 270 220 460 650 530 730 1030 840 1000 1410 1150 200 280 230 470 670 540 740 1050 850 1010 1430 1170 210 300 240 480 680 550 750 1060 870 1020 1440 1180 220 310 250 490 690 570 760 1080 880 1030 1460 1190 230 330 270 500 710 580 770 1090 890 1040 1470 1200 240 340 280 510 720 590 780 1100 900 1050 1490 1210 250 350 290 520 740 600 790 1120 910 1060 1500 1220 260 370 300 530 750 610 800 1130 920 1070 1510 1240 270 380 310 540 760 620 810 1150 940 1080 1530 1250 280 400 320 550 780 640 820 1160 950 1090 1540 1260 290 410 340 560 790 650 830 1170 960 1100 1560 1270 300 420 350 570 810 660 840 1190 970 1110 1570 1280 310 440 360 580 820 670 850 1200 980 1120 1580 1290 320 450 370 590 830 680 860 1220 990 1130 1600 1300 330 470 380 600 850 690 870 1230 1000 1140 1610 1320 340 480 390 610 860 700 880 1240 1020 1150 1630 1330 350 500 400 620 880 720 890 1260 1030 360 510 420 630 890 730 900 1270 1040
  30. 30. 6. Tying method of Rebar When tying the bars, the hook is used in Korea and Japan. While in other countries, the wrench is used. Tying the bars requires many times of practice. All the places that two bars meet are recommended to tie. However, it is usually accepted to skip all other crossing point in case of light-loaded bars. There are several types of binding the bars such as cross tie, Saddle tie with twist, wall tie and double string tie, etc.1) Cross tie Ties to fix the stirrup onto beam ties to prevent hoop from slipping down2) Double string tie Same procedure when you use hook to tie the bars mostly used in Asian countries applicable to many construction sites such as wall, slab, etc. You must tie different tying each bars.
  31. 31. 3) Saddle tie with twist Ties the bars in high beam or wall to fix them firmly or to avoid twisting off4) Wall tie - The same procedures as saddle tie with twist and tie it as the method of right picture - Ties the bars that extend from the wall to keep the required positions and distances between them5) References Every crossing point of the bars at the bottom span should be tied, and wound more than 3 times. When tying the bars at the top span, tie the bar changing the tying direction(one time to left and next to the right) When tying the bars in a slab, you may skip every other, but it is better to wind the hoop before tying the bars. It is advised to wind the hoop 3 times at the important crossing point. There are several kinds of ties, and in construction works, #20 tie is normally used in folded state.
  32. 32. 7. Bar support , Spacer Bar support is usually to hold the location of placed bars, and spacer maintains the cover depth of a member as intended. In addition, they also prevent dispersions of located bars due to high impacts and undesirable vibrations. Especially in reinforced concrete, cover depth, which is one of the important factors for durability, should be seriously considered. Undoubtedly, bar support and spacer should be strong or even stronger enough to to support the bar and endure high impacts When metal is used to reinforcement, spacer must have special rust protection on the portions nearest the face of the concrete by attaching pvc cap. Part Type Q’ty & Layout Remark Area : 4m2 - 8EA By calculation if Mat Foundation 16m2 - 20EA thickness is over 1,500 Foundation Bar Space - around 1.5m Install to top span, Beam (Closer than 1.5m at the end) bottom span, sides At the 1st tie hoop in the top span In the middle of pillar in the middle Pillar span less than 1.0m of pillar width 2EA More than 1.0m of pillar width 3EA Steel Reinforcement At the first tie hoop in the top span Wall & 1.5m from the top in the mid span Basement Concrete material Transverse spacing 1.5m Outside Wall Within 1.5m at the end At the top and the Bar Space - around 1.5m bottom except side Beam beam (Closer than 1.5m at the end) Also on the sides in the side beam Bar 1pc(1.3/m2) per width by long, Slab each 1m at the top & bottom bar
  33. 33. 8. Conventional processing work tools Once the construction work is initiated, reinforcement needs to be manufactured, several different tools are used depending on the type of work.1) Types of conventional tools. Bending die : die to bend the bar on Bender : bends the bars Hammer : adds force to cut the bar Lower cutting blade Upper cutting blade Mat plate to fix the cutbar Various types of bar bender and bar cutter are available(see Chapter.3)2) Preparation before reinforcement of rebar work Fabricate the bar bending die (The height should be about 850mm). Prepare the power cable to connect the bending machine and binding machine Prepare chalk or other writing instrument to mark the dimension. Prepare the tools and bending die.
  34. 34. <Bending Table> Bending Pin Bending Plate <Manual Bender> Prepare per rebar size <Mat> <Low cutting blade> <Upper cutting blade> <Manual Cutter><Hammer>
  35. 35. 3) Tools needed if assembling does a. Measuring tape ~ measures the dimension b. Hook ~ a tool to tie the bar(usually used in Korea and Japan). Wrench is used in Europe and South-East Asia c. Conventional shearing machine ~ cuts a bundle of binding wires to bind the bars in a beam, a pillar(divide to half) or a slab(divide to 3parts) d. Plumb ~ using to assemble the pillar bar vertically e. Bar-tying hook ~ ties #8 wire <Measuring tape> <Plumb> <Inch Ruler> <Bar-tying hook> Tools mentioned above are rather old type ones, and newly developed tools are in the construction site now.
  36. 36. 9. Point of conventional processing work1) Marking the bending point (example : D10~D13 stirrup , hoop) Mark the bending point on the bending die. Be sure to nail the bending panel on the bending die to fix it firmly. Nail Processed dimension Bar back- stopper pin Working point Keep the 1.5d of tolerance from the working point (in case of D10, keep the 15mm of tolerance)2) Determining the location of the manual bender Be careful Make space +20mm width from the bending start pin. The space of working point must over 20mm than using rebar. The position of bender must have space of 20mm from working point to bender using to head of handle. (install within eye shot)
  37. 37. 3) Processing Bend the bar a little more than intended angle. Make sure that there is 20mm of distance between the tip of bender and bending point. The distance between these two points should be neither too far nor too close for high bending accuracy. With your left hand, gently push the bender outward to bend the bar, while you grab the bar with your right hand to fix it firmly.4) Posture and position of foot It is recommended that bending direction should be from right to left. The left hand that pushes outward to bend the bar should be at the level of your belt. Your right foot just turns the direction, while your left foot moves quickly to bending direction(Weight shift along bending direction)
  38. 38. 5) Currently using machinery General Bender TYB-D35 Mobile Cutter TYC-D29A
  39. 39. 10. Calculation of the quantity of Rebar material1) Extra of rebar In case of deformed bar, extra is 3% in general when including fixed & splice length of rebar, however, it is proportional to bar size. 16mm or larger : more than 5% extra 3% of 100ton is 100 0.03 = 3ton Rebar calculation included extra 3-8% after calculating fixing & splice. Therefore, those works will prevent from the reason of illegal construction practices with correct quantity & regular position carryout of construction by calculating bar-list with shop drawing. If rebar will be processed in rebar processing factory , basically extra is as follows. In construction work 3%, in engineering work 6%, support work 3~4%. You have to consider the economical efficiency and construction carryout efficiency in site after analyzing in advance about extra percentage per rebar size by the criterion per construction carryout area.
  40. 40. 2) Base plate(Footing) <Example : 1> <Example-1> In 2000 2000 foundation, shown as above, requirement of bar includes 20pcs HD22 bars of 1,840mm (80(cover depth) 2(both ends) = 160mm is extracted from 2,000(original length of foundation), 2pcs D19 assist bars of 2,601mm(1,840) 1,414 ( 2 ), diagonal direction) and 4pcs short diagonal bars(2 bars in each diagonal direction) of 2,318mm(1,640(200mm is extracted from main bar length 1,840mm) 1,414 ( 2 ). HD22 1,840mm 20(foundation) = 36,800mm Weight = 36.8m(36,800mm) 3.04(unit weight) = 111.872kgf HD19 2,600mm(long bar) 2 = 5,200mm Weight = 5.20m(5,200mm) 2.25(unit weight) = 11.700kgf HD19 2,310mm(short bar) 4 = 9,240mm Weight = 9.24mm(9,240mm) 2.25(unit weight) = 20.79kgf Actual requirement of bar is HD22 = 111.872kgf HD19 = (11.700kgf+20.79kgf) = 32.49kgf LOSS(left bar strip) : The original length of bar before cutoff is usually 8,000mm. In case of above, 4pcs 1,840mm bars are produced and 640mm of bar strip is left. 5 bars are needed for foundation, hence 640 5 = 3,200mm of bar strip is left. Its net weight is 3.20m(3,200mm) 3.04(unit weight) = 9.72kg. Actual requirement of bar is 8m 3.04(unit weight) 5 bars = 121.6kg
  41. 41. <Example : 2> What is the weight of D10 8m bar? 0.56kg 8m = 4.48kg How many D13 bars(8m criterion) in 2ton? 2,000kg (0.995kgX8m) = 251EA(standard is 240EA) Arrangement in foundation (base plate F) ( All the unit in drawing should be in mm) HD16 rebar 200mm space HD19 rebar 300mm space HD13 reinforcement bar 3EA HD16 = 2,000-(80(cover depth) 2(both ends)) = 1,840 (cutoff dimension) HD19 = 3,000-(80(cover depth) 2(both ends)) = 2,840 (cutoff dimension) HD13 = 1840 +2840 = 1840 1840+2840 2840 = 3,383 (cutoff dimension) (Note. x = x x, 10 = 10 10 = 100)Here, multiply unit weight and number, then net weight of bar is HD16 = 1.84m(1,840mm) 1.56kg = 2.87kg 2,840 @200 = 14.2 14 14+1 = 15EA 87kg 2. 15 = 43.05kg
  42. 42. HD19 = 2.84m 2.25kg = 6.39kg 1,840 @300 = 6.13 6 6+1 = 7EA 6.40kg 7 = 43.73kg HD13 = 3.38m(3,380mm) 0.995kg = 3.36kg Weight = 3.36kg assist bar(3+3) = 20.16kg Among 6 assist bars, two(2) of them in 3,380mm and the other(4) in 12,320mm (4x3,080mm : 300mm shorter) Net weight is 43.05+44.73+21.60 = 109.38kg and add 5% extra, hence 114.84kg isrequired.
  43. 43. 3) Base(footing) and pillar As various footing types like continues footing, single footing and mat footing, there are many shapes of footing, that is, triangle, right triangle, square, rectangle, pentagon, circle, multi-layer plate, etc. In this book triangle shape footing and single reinforcement footing are dealt with. In case of footing shown left cover depth, the type of bar and the size of bar should be considered. HD22@200 In addition, the reinforcement at footing-pillar junction should be included here. HD19-6EA Before bar cutoff, the size of C1, HD22@200 the area of main reinforcement, the size of hoop and the spacing of F1 plane stirrup are all considered consulting cover50 the bar list. Calculation : cover80 Footing shown left is in contact with soil, hence cover depth is 80mm at each end(80 2 = 160 at both ends). Section 160mm is extracted from footing length 2,000mm, and this(1,840mm) is divided with spacing 200mm. D10@300 Then 10 reinforcement(at every 9 spacing +1 at the end) is required D10@300 upper part, lower part @150 here. HD22-8EA Now reinforcement is in two directions and therefore we need 20 reinforcements.
  44. 44. 4) Pillar Similar to footing, there are many shapes of pillar, that is, triangle, right triangle, square, rectangle, pentagon. circle, etc. The worker is recommended to earn a lot of working experience. Calculation of pillar In calculation, tie hoop, stirrup, main bars in column and the others should be included here. D10@300 First extract cover depth from hoop size D10@300 (400mm), and cover depth in the basement upper part, lower part @150 and above the ground should be different. HD22-8EA Net length cover depth 400 - (40+40) = 320 (dimension) 4(4sides) 1,280 + 100mm of hook then, cutoff length is 1,380mm. Since net length of hook is 100mm, only 100mm of extra length is added here. If the bar size is D10, one end is hooked in circular, so 2 times of bar diameter (20mm) is extracted here, As 5 hooks are needed and hook length is 100mm at each end(200mm in total), 80mm is extracted from 100mm. Then this 80mm is added to produce 200mm of hook length.
  45. 45. 5) Calculation of main rebar If you will carry-out with 8,000mm rebar including both fixed length(anchor) from total length of 1 span , you just add the splice length from rebar diameter to use. Example) Total length 62,000mm + both fixed length(anchor) 1,000mm = Gross Total 63,000mm. When using HD19 rebar, splice length is 19 40d = 760mm. Rebar 8,000mm - splice length 760mm = 7,240mm. Gross Total 63,000mm 7,240mm = 8.7 piece (long bar 8piece & rest 5,080mm) Above splice length is 5,080mm including anchor. You can calculate it as above , but you have to carry-out the splice position as soon as closely by calculating several methods if spice position is not fit well.<Sample of processing> END CENTER long bar processing splice rebar long bar outside end end top-bar center top-bar in span end top-bar center top-bar in span outside end
  46. 46. 6) Calculation of top rebar Please refer to the method in construction site as follows because it is very difficult to explain in theory. If 1 span is 8,000mm, 4,000mm will be center part and add 40times(40d) + rebar thickness is the length of top rebar in center part & end. You cut as 4,000mm +760mm = 4,760mm. When assembling current processing status , center part is from beam to upper part rebar splice position and end is lower part rebar splice position if splice rebar 2 pcs 4,580mm + long bar processed 1pc as upper part rebar and splice rebar 1pc 4,580mm + long bar processed 2pcs as lower part rebar will be used. And so, you assemble it mutually crossed and upper part is 2 bar from 3 bar from splice position.7) Calculation of hoop If pillar size is width 400mm length 500mm, actual processing size is 320mm, 420mm except cover 40mm each(both 80mm). When processing hook by hand, it will be included 40mm from total length. When using Taeyeons bending machine, it will be included 50mm from total length . coating thickness 40 process size Cut size : (420 2)+(320 2)+50 = 1,530mm Example of hoop usage : To avoid wrong bending of main bar and to restrict inner concrete , you maintain the space and no problem to assemble with 135 hoop at one side.
  47. 47. 8) Calculation of stirrup If beam size is length 500mm , actual processing size is 420mm , 420mm except cover 40mm each(both 80mm). If beam size is width 300mm , actual processing size is 220mm , 220mm except cover 40mm each(both 80mm). Including hoop 50mm , you can use Taeyeons bending machine. END CENTER Process size Cut size : (420 2)+(220+50(hook)=1,100mm Example of stirrup usage : To surround tension & compression bar and to restrict inner concrete , you maintain the space and bend with over 135 as stirrup end length. Taeyeon bending machine will be processed 90 or 135 with free by manufacturing of special tool & electric circuit.9) Fact of processing According to rebar thickness and to bending angle , 2 times of rebar thickness will be used because of bending by circle of bending part than the length per actual straight line. <Tolerance of rebar process size> Drawing Item Symbol Tolerance( ) stirrup, tie hoop A, B 5 below HD25 A, B 15 main bar over HD29 A, B 20 length after processing - 20
  48. 48. 10) Changed size if it bent 1 angle per specification When bending 1 angle, rebar D10 will be increased by 2cm each. When bending 1 angle, rebar D13 will be increased by 2cm each. When bending 1 angle, rebar D16 will be increased by 3cm each. When bending 1 angle, rebar D22~25 will be increased by 5~6cm each. Because bending part will be bent like R type, rebar will be less used per rebar diameter. Regarding processed rebar, it will be less used also by measuring with outside diameter size. If actual cut size is D10, (42 2)+(32+8(hook)) = 124cm Note) Process size must be outside diameter size of processed rebar.11) Tolerance of processed size Item Tolerance( ) stirrup, tie hoop, spiral rebar 5 processed size under D25 of deformed bar 15 others D19~D41 of deformed bar 20 total length after processing 20
  49. 49. 11. Foundation(Base) rebar arrangement1) Foundation(base) work In foundation work, the lean concrete underneath the footing concrete, is very important. Without it, constuction site, on which a building will be raised up, it would not be clean and stable disturbing construction work. Be sure to make lean concrete working mat having at least 50mm of thickness. If F.L. of lean concrete is not fit, there are difficulty in fix S.L.2) The height of spacer Bar spacer is used to maintain the arranged bar balanced. When arranging the bars or flooring, stones and bricks can not be used to support them. You have to prepare spacer in advance because there are high possibility of unbalance when using stones or bricks to level the ground. (in case of spacer height lean concrete top is 60mm) < Cover thickness of rebar > part to not contact land part to contact land over 80mm of cover thickness in foundation rebar over 50mm of cover thickness than pile head on base concretelean concrete
  50. 50. The reason that the top of piles is embedded into foundation is that , in case of an earthquake , the pile causes bending fracture. Especially , when the ground is unstable , there should be specified directions on the drawings.(in case pile cover bending moment & compresssion or cover tension properly only) 6-D13(circular arrangement) PC Steel wire 2 times of pile diameter Fillup CON’C HOOP D13@150 4 (foundation CON’C) Hole closure PC or PHC PILE3) Independent Foundation(Single Footing) Usually in double footing and floating foundation , remained bar length is bent up and down to splice them together as depicted below. However, the remaining parts of the bar can be cut off to reinforce the foundation. <In case of securing splice length> <In case of not securing splice length> when securing In case of below splice length splice length standard hook
  51. 51. 4) Foundation(base) pillar tie hoop The main purpose of the tie hoop is to restrain the transverse load in order to relieve vertical load into pillar. Even though foundation concrete has capacity to support the loads from the pillars, tie hoops help main bars be fixed at which they should be and it is important job. <Before reinforcement> <After reinforcement> main bar tie hoop should be pillar @300 distance per slab the drawing regulation, tying footing MAT bottom tie hoop lean concrete spacer pillar The tie hoops at the bottom hold the bars of the pillar in lean concrete and marking on the mould form is compared with drawing to ascertain the center of the pillars. <Foundation plate> pillar location marking eccentric The outer pillar must check main bar line.5) Foundation(base) upper-support(Wooma) rebar - Foundation thickness : below T=1,000mm for HD16, over T=1,000mm for HD19 space should be @1000-@1500
  52. 52. 12. Pillar rebar arrangement1) Indication of pillar(C) Main bar drawing - It indicates the length of span by the criterion of pillar and wall, etc. and indicates the position of pillar & wall. <Example> C - pillar BC1 - #1 underground pillar 1C1 - #1 first-story pillar 500 500 - actual size of concrete 8-HD19 - 8pcs of HD19mm rebar D10 @250 - install per 250mm of HOOP distance D10 @250 - install per 250mm of DIA HOOP distance Be careful of this point if there are rebar quantitys differences according to pillar assembly x0, x1 or y0,y1 direction.
  53. 53. 2) Indication of floor 2SL(upper concrete) 2FL(upper part’s closing condition) 1) GL - GROUND LEVEL 2) FL - FLOOR LEVEL Height of floor (ground level per floor) 3) SL - SLAB LEVEL (upper part of structure per floor)
  54. 54. 3) Sequence of pillar assembling < Stand the same to diagonal direction if each side is even. > < Stand the same to all directions if each side is odd. > < Stand the same to one direction if each side is even & odd. >
  55. 55. 4) Tying method of pillar Even the tiny little requirement for the construction should be taken into consideration. Keep the pillar reinforcements vertically and splice the bars 3 times. Upper and lower parts of the reinforcements should be cross-tied. When tying the corner of tie hoop, it is better to wind the tying wires changing directions up and down to let it not to be hung down. It is also recommended that worker wind the tying wires at least one time in advance to hold the main bar to its original position. main bar tie bar Tie bar for assisting pillar should be at every distance to install tie hoop . Diamond type General type
  56. 56. Bind the tie hoops clockwise(as shown below) and spacing at the top and bottom levels of vertical reinforcement should be within of hoop spacing beginning at 50mm from the bottom of the floor.5) Position of pillar tying In pillar bar slice, follow the instructions on drawings in order to splice them adequately, that is, if not, the length of reinforcement is not fit for column with the reason that usual 8,000mm bar is cut into two 4,000mm bars to splice. good location of splice available location of splice bad location of splice [Note] It is desirable that reinforcing bar should be in a variety of sizes, but 8m bar is usually available in the market. In other words, if you need a bar other than 8m in size, you should give a customer- order for it, which does not go well with economical strategy. Reinforcing bars from D10~D16 do not have much problem in using them as reinforcement for slabs or bearing walls. We have some advantages here. Bar loss and the frequency of splice will be decreased if using bars of 8m ~ 12m length by mixing.
  57. 57. Splice of pillar and pillar under 75 over 75 max. 150 Dowel rebar splice fixing max. slope max. 150 splice/ fixed length of tension bar slope rebar splice using dowel rebar6) Cross assembling of pillar and beam(only for outer pillar) Dont fill up tie hoop to assemble beam the crossed part of pillar & beam. In this case , there are difficulty in carrying out the construction but you must fill up tie hoop of outside. Especially, you should prevent from the protruded main bar by filling up tie hoop on outer pillar and edge pillar. pillar pillar tie hoop from current carry-out beam rebar arrangement of construction
  58. 58. In case over 600mm of pillar size , you should fill up support tie hoop by shopdrawing.You should get rid of support tie hoop in order to workers entrance to pillar tubeto connect #8 wire for working of pillar outer appearance.After this, the worker should not forget to bind the assist wire before he gets out.In case the splice length for pillar splice is shorter than required, be sure to destroythe concrete to maintain splice length but it is impossible possibility to executeactually.Therefore, you should check the availability of welding splice, compressed splice,mechanical splice.
  59. 59. 7) Correction of pillar Bend the bar gently at a very low level Pillar correction angle should not exceed of overall angle Heat should not be added to correct the main bar because it makes the strength of rebar, just destroy the part that needs correction and bend it of overall angle. Destroy the part that needs correction and modify it. These are 2 cases of correction depending on correction angle. When the correction grade is low If corrected angle is about , insert the bar into pillar after bending. Bending after concrete work. When the correction grade is higher than , change the bending angle to and cover the pillar as thin as possible. Increase to minimum pillar thickness Pillar rebar protruded to outside.
  60. 60. 8) Detailed drawing of pillar and beam rahmen(arrangement) Dont apply compression splice length except pure compression material. Regarding bending material , apply B class splice for tying near max. stress point and apply A class splice for the rest block. A class tension splice fixed length main head A class tension splice 2nd floor HO The fixation of upper bar calculates fixed length from the main bar bend area of pillar’s upper part, not from the inside of pillar space 1st floor HO When the beam is arranged, the bottom bar should be all tied, and the stirrup upper binding supported by spacer should be tied 2,3 times tightly. tension splice (over B class splice length) tension splice
  61. 61. Apply to anti-earthquake slab rebar beam lower part barmax. max. In case all plane of In case some plane of pillar has beam pillar have beam (ground outside pillar) Lo max. size of pillar section So 8db(main bar) Lc/6 24db(hoop bar) 45 1/2(min size of pillar section) 30
  62. 62. 13. Beam rebar arrangement1) Principle of beam rebar arrangement Calculate the size and depth of beams according to the drawing and arrange them in a suggested order, that is, exterior beams and big beams(G) & deep beams first and then binding small beams(B beams) later. Supervisor has to check if the bar used at the top span meets the requirement on the drawing. Shorter bar than required might be used to save cost when the span is longer than 8,000mm, the bar standard. The bar might deflect from undesirable vibration when placing concrete if the double reinforcement or top end bar are tied with tying wires. To prevent this, 3 pieces of stirrups are used to tie the bars at the top and as many pieces to place double-leg bar & top bar on the bottom bar. <The height will be changed by th rebar size> Stirrup:end support(S.T.) Center support(S.T.) Cap tie bar should carry out 1 by 1 at least. The 1st stirrup should be arranged with the space 50mm from the perimeter of side pillar. 1st stirrup 1st stirrup arrangement beside arrangement beside of pillar’s main bar of big beam main bar big beam @/2 or under 50mm from side pillar @/2 or under 100mm from side big beam
  63. 63. The splice for upper part rebar of beams end and lower part rebar of beams center apply tension splice length. <Main bar arrangement> middle/ middle/ big value big value min min or continuance min or continuance <Distance of stirrup> end center end end center Apply the above except the case of marking separately on beam chart. S1-S4 : stirrup distance2) Types of stirrup <a> Open type - beam without cap tie bar - beam to be arranged by front end without twisting - beam without anti-earthquake plan <b> Closed type slab on both sides slab on one-side no slab on both sides
  64. 64. distance of member splice against total over 30cm over 45cm - beam with front end and twist - in case of anti-earthquake plan3) Position of beam tying(splice) Splice location : diagonal line Calculation of bender When bent bars are used to reinforce beams, bending point of the bar is usually calculated as distance from the center of the pillar. However, it is formal to divide it into 4 parts from the end of beam reinforcement to the other end. wall girder pillar
  65. 65. An example for processing Anchorage(fixed) bars are classified as the top bars and the bottom bars, when the former have tensile loads and the later have compression loads. Therefore, the top bars and bottom bars set fixed splice length with same method because it has difficulty in working separately for processing and assembling.(criterion of concrete structure plan) In a real construction, 40d is used for both of them for convenience sake. Cover depth of beams Stirrup with spacer should be tied several times. Pay attention when arranging reinforcements in order to have enough cover depth. X beam spacer cover Y beam thickness 40 height 40 Y beam X beam4) Bending position of bender (classification of tension & compression) Tension fixation Tension bent bar fixation A class tension splice A class tension splice (Top floor) penetration of bent bar top bar bent bar (General floor) Using the bent bars in beams is Japanese style, while cutoff bar is now in common.
  66. 66. 5) Beam rebar arrangement(CUT TYPE) In case of beam 0.3L or 0.3L1 0.3L or 0.3L1 big value big value In case of girder 0.3L or 0.3L1 0.3L or 0.3L1 big value big value standard hook fixed length Note 1) * : apply general bars splice length(A class splice) as standard splice length & fixed length of rebar(22page 6)) for above size 2) ** : fixed as standard hook form about center part bottom bars 25% 3) splice length according to splice position of rebar arrangement - tying on upper part rebar(beam) block : apply A class tension rebar splice tying except upper part rebar(beam) block : apply B class tension rebar splice - tying on lower part rebar(beam) block : apply A class tension rebar splice tying except lower part rebar(beam) block : apply B class tension rebar splice
  67. 67. 6) Beam rebar arrangement by using stepped pulley The types of step are classified as planar step, elevated step, step in material according to their shapes. In each case, arrangement is in vertical or in horizontal. If the worker has no choice but to bend the bar, bend it at low grade. When the mid span of a beam has steps as shown below left, the bar might be necessarily bent, which is quite undesirable. The load tends to straightly pass through. If pulled out, the bar does not straighten as it looks. Far from straightening, it will break or fracture. Needless to say, it is recommended that the worker cut the bars and arrange them separately, as depicted below. breakable due to the tension tension fixed length tension fixed length Wrong method Correct method
  68. 68. 7) Hunch beam Bend the bars at the bottom in a hunch former and anchor them onto the pillar. Bend a half of the bars at the bottom to let the anchorage length penetrate the pillar and anchor near the hunch point. One size bigger stirrup should be used at the hunch point. S.T. one size bigger stirrup stirrup8) Pillar-holding rebar (Butterfly stitching rebar/Stirrup closing rebar) As few drawing gives direction on pillar-holding rebar, it is common to use it at every third stirrup. If not, all junctions of pillar-holding rebar should be confined per every stirrup. <butterfly stitching rebar> processing (current) (revised) Better if one end hooked 135
  69. 69. 9) Symbol of beam Continuous end of beam Center of beam Exterior of beam Interior of beam Outside of beam center top bar : HD22-2 end stirrup:arrange 200mm distance-D10 upper part : HD22-3 lower part bar : end top bar : HD22-2 HD22-3 center stirrup-arrange 250mm distance-D10 support bar : HD13-2EA EXT(exterior) CENT(center) END(end) 400 500(stirrup process size : 320 420) tension splice (B class splice) stirrup : arrange 200mm distance-D10 upper part bar : HD22-3EA support bar : HD22-3EA lower part bar : HD22-3EA END(end) CENT(center) 300 500(stirrup process size : 220 420)
  70. 70. 10) Detailed drawing of beam rahmen(arrangement) horizontal rebar : HD10@200(arrange 200mm distance-D10) vertical rebar : HD10@200(arrange 200mm distance-D10) END(end) CENT(center) 400 500(stirrup process size : 320 420) tension splice hoop : arrange 250mm distance-D10 support big bar : arrange 250mm distance-D10 400 400(hoop process size : 320 320) main bar : 10-HD19 tension splice (B class splice) Each floor bottom structure plane figure symbol & beam chart symbol
  71. 71. You should check pillar size & rebar Q’ty per each floor, and also arrange afterchecking rebar Q’ty & drawing of outer pillar’s front and side.

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