1 2/2013 ANCHOR BOLTS INSTRUCTIONS FOR USE - Threaded rebars ATP, AHP, AJP - Threaded high strength steel bolts ALP-L, ALP-P, AMP ATP AHP ALP-L ALP-P AMP Eurocode design according to EN (2005) & EN (2004) Certified Finnish product manual (NA: FIN)
2 ANSTAR OY, Erstantie 2, FIN Villähde page 2 CONTENTS Page 1 PRODUCT DESCRIPTION MATERIALS AND STRUCTURE PRODUCT RANGE MATERIALS MANUFACTURING QUALITY CONTROL DIMENSIONS ATP and AHP rebar bolts ALP anchor bolts AMP anchor bolts CAPACITIES BASIS OF DESIGN BOLT CAPACITIES COMBINED LOADINGS THE USE OF ANCHOR BOLTS RESTRICTIONS DESIGN PRINCIPLES PLACING OF BOLTS Minimum bolt edge distances for normal forces Minimum bolt centre to centre distances for normal forces Minimum bolt edge distances for shear force ADDITIONAL REINFORCEMENT Connection reinforcing principle Column to column joint Placing short stud head anchor bolts in slabs or low foundations Placing short stud head anchors in a foundation column Placing rebar bolts in a foundation column Placing AMP bolts in a column ADDITIONAL CLAUSES FOR T40 REBAR CORRECTION OF CAPACITY VALUES Change of concrete strength Small edge distance Small centre to centre distance Durability and concrete cover INSTALLATION FORMING A BOLT GROUP BOLT ASSEMBLY AND TOLERANCES BENDING AND WELDING OF BOLTS COLUMN INSTALLATION SAFETY PRECAUTIONS INSTALLATION CONTROL Instructions for bolt assembly Instructions for column installation Download free from ColJoint design program for bolt/column shoe connection
3 ANSTAR OY, Erstantie 2, FIN Villähde page 3 1 PRODUCT DESCRIPTION The anchor bolt transfers forces acting in the bar direction to foundation or lower column by rebar bond or by stud head anchoring. Connection shear force is transferred to the concrete structure by the concrete edge pressure acting on the bolt shaft. 2 MATERIALS AND STRUCTURE 2.1 Product range The anchor bolt product range include following bolt types: ATP AHP ALP-L ALP-P AMP, -M Short rebar bolt with stud head anchor Rebar bolt with straight bonding rebar Short high strength anchor bolt with stud head anchors High strength anchor bolt with straight rebars Standard bolt for moment stiff connection between precast beam and column Beside the bolt the standard delivery contains 2 nuts and 2 round washers. For the AMP bolt lower nut and washer can be replaced with a round threaded steel plate. 2.2 Materials Rebar T16-T32 SFS 1215 (EN 10080) A500HW (B500B), f y = 500 N/mm² Rebar T40 NS B500NC ALP thread High strength steel f y = 700 N/mm² Imacro M, Ovako f u = N/mm² Nut DIN 934 Grade m8 ATP, AHP Grade m10 ALP, AMP Washer EN Grade S235JR+AR 2.3 Manufacturing Method of manufacturing Rebars and bolt materials are mechanically cut Anchors are MAG welded with a robot or by hand to high strength steel bolt. Weld class C EN-ISO Threads M16-M52 are rolled and M60 is cut. Anchoring stud is hot forged and air cooled. Surface treatment options: 1) Black steel with lightly oiled thread is standard supply 2) Hot dip galvanizing according to EN ISO 1461 including also nuts and washers - ATP and AHP bolts are galvanized troughout - threaded part of ALP and AMP bolt is galvanized before welding black anchors Manufacturing tolerances Total bolt length Length of thread Metric thread ISO ± 10 mm +5,-0 mm 6g 2.4 Quality control The quality control follows the requirements set by the Finnish Code of Building Regulations. Anstar column shoes are certified by the Finnish Concrete Assosiation according to Eurocode and the exter-
4 ANSTAR OY, Erstantie 2, FIN Villähde page 4 nal quality control of manufacture is provided by Inspecta Sertifiointi Oy. 2.5 Dimensions ATP and AHP rebar bolts ATP and AHP rebar bolts are used to join columns to foundations in connections transferring normal forces, shear forces and bending moments. ATP bolts are used in connections where short anchoring lengths are needed, such as in slabs and short foundation columns. AHP bolts can be used in foundations where there is enough space for straight rebar anchoring. K Ø T S ATP K L Ø D washer AHP L Fig. 1. ATP and AHP foundation bolts Table 1. Dimensions of ATP and AHP anchor bolts (order AHP with desired L) Type L other lengths K A s M Ø D S T weight mm in stock mm mm 2 mm mm mm mm mm kg ATP M16 T ,7 ATP M20 T ,2 ATP M24 T ,2 ATP M30 T ,3 ATP M39 T ,0 AHP M16 T ,5 AHP , 2000, 2500, M20 T ,7 AHP , 2000, 2500, M24 T ,8 AHP , 2500, M30 T ,2 AHP M39 T ,6 Also available as hot-dip galvanized. Table 2 and figure 2. Rebar lap length l 0,min (EC2) for bolt tensile force concrete strength C25/30 C32/40 bond condition 1 1,0 1,0 1,0 1,0 0,7 concrete cover 2 0,7 1,0 0,7 1,0 1,0 percentage 6 1,5 1,5 1,5 1,5 1,5 AHP AHP AHP AHP AHP l 0,min
5 ANSTAR OY, Erstantie 2, FIN Villähde page ALP anchor bolts ALP anchor bolts are used to join columns to foundations in connections transferring normal forces, shear forces and bending moments. ALP-L bolts are used in connections where short anchoring lengths are needed, such as in slabs and short foundation columns. ALP-P bolts can be used in foundations where there is enough space for straight rebar anchoring. K 50 Ø ALP22L,..., -52L ALP60L ALP-L K 50 L Ø D D ALP36P ALP39P ALP45P ALP52P ALP60P ALP22P ALP27P ALP-P L D D Fig. 3. ALP anchor bolts Table 3. Dimensions of ALP anchor bolts Type L K A s M Ø D S T weight mm mm mm 2 mm mm mm mm mm kg ALP22L M22 3T ,6 ALP27L M27 3T ,0 ALP30L M30 3T ,7 ALP36L M36 3T ,0 ALP39L M39 3T ,6 ALP45L M45 3T ,5 ALP52L M52 3T ,2 ALP60L M60 4T ,6 ALP22P M22 3T ,6 ALP27P M27 3T ,7 ALP30P M30 3T ,0 ALP36P M36 4T ,8 ALP39P M39 4T ,7 ALP45P M45 4T ,6 ALP52P M52 4T ,3 ALP60P M60 4T ,0 Also available as hot-dip galvanized (only threaded bar not anchors) L = Total length of bolt K = Length of thread K j = Area of threaded cross-section M = Metric thread size Ø = Amount and diameter of rebars D = Combined anchor space needed S = Washer diameter T = Washer thickness
6 ANSTAR OY, Erstantie 2, FIN Villähde page AMP anchor bolts AMP anchor bolts are used in moment stiff precast beam-to-column connections. Bolt dimensions have been designed for limited embedment space in concrete column. AMP bolts can also be used in connections where short anchoring lengths are needed, such as slabs and short foundation columns to transfer normal forces, shear forces and bending moments. AMP-M bolts are used to connect two precast beams facing opposite sides of the column. Product code is AMP-M-L (for example AMP52M-1480). AMP AMP-M K 50 U A Ø K 50 Column width Ø 50 K B L L Fig. 4. AMP anchor bolts Table 4. Dimensions of AMP anchor bolts Type L K A s M A B Ø U S weight mm mm mm 2 mm mm mm mm mm mm kg AMP M T ,5 AMP M T ,8 AMP M T ,7 AMP M T ,3 AMP M T ,8 AMP36M-L M T AMP39M-L M T AMP45M-L M T AMP52M-L M T AMP60M-L M T L = Total length of bolt K = Length of thread K j = Area of threaded cross-section M = Metric thread size A = Length of anchor plate B = Width of anchor plate Ø = Diameter of rebars U = Anchor plate distance from thread S = Washer diameter
7 ANSTAR OY, Erstantie 2, FIN Villähde page 7 3 CAPACITIES 3.1 Basis of design The anchor bolts have been designed according to: Tension: - EN :2005 Design of Steel Structures, General rules - EN :2005 Design of Steel Structures, Joints Tension resistance has been calculated with M2 = 1,25 (NA: FIN) - EN :2004 Design of Concrete Structures, General rules Shear: - Elastically embedded bolt with edge distance 10Ø according to De Beer A slightly conservative capacity compared to CEN/TS :2009 chapter 6.3, suitable for anchoring machinery (smaller displacements in serviceability limit state) 3.2 Bolt capacities The anchor bolts have been designed for tension and compression capacities calculated from the thread cross-section (EN : 3.6). The bolt capacity is the same as the capacity for corresponding column shoe. Table 5. Design capacities for rebar bolts. Concrete C25/30. Bolt Normal force Shear force Corresponding good bond, 2 = 0,7 N Rd [kn] V Rd [kn] column shoe ATP16 AHP APK16 ATP20 AHP APK20 ATP24 AHP APK24 ATP30 AHP APK30 ATP39 AHP AK39 Table 6. Design capacities for high strength steel bolts. Concrete C25/30. Bolt Normal force Shear force Corresponding good bond, 2 = 0,7 N Rd [kn] V Rd [kn] column shoe ALP22L,-P APK24 ALP27L,-P APK30 ALP30L,-P APK33 ALP36L,-P AMP36, -M APK36 ALP39L,-P AMP39, -M APK39 ALP45L,-P AMP45, -M APK45 ALP52L,-P AMP52, -M APK52 ALP60L,-P AMP60, -M APK Combined loadings For combined tension and shear loads the following equation should be satisfied: (N Ed / N Rd ) 1,5 + (V Ed / V Rd ) 1,5 1,0 N Ed = Design tension load N Rd = Tension capacity V Ed = Design shear load V Rd = Shear capacity
8 ANSTAR OY, Erstantie 2, FIN Villähde page 8 4 THE USE OF ANCHOR BOLTS 4.1 Restrictions Anchor bolt capacities have been determined for static loads. When designing dynamic actions larger load safety factors should be used and the connection system should be analysed for each case. Using capacity values require that the minimum centre to centre and edge distances as well as reinforcement instructions for transferring bolt loads to concrete are followed. Impact ductility properties of ALP and AMP bolt material enables normal usage to - 40 C. 4.2 Design principles In grouted joints bolts usually transfer only tension loads, while shear load is transferred by friction (EN : 6.2.2). In ungrouted joints (installation) all loads will be carried by slender bolts. Shear loads are bending the threaded bolts and the compression side will determine the bolt size needed. Compression load acting on a bolt (symmetrical bolt group) N Edp = N Ed / n + M Ed / (0,5 * H * n) N Ed M Ed H n joint design compression load joint design bending load bolt c/c distance amount of joint bolts M Ed N Ed M Bolt bending moment caused by shear load Q Ed M QEd = 0,5 * Q Ed * (G + M) / n G Q Ed G M n joint design shear load grout thickness (mm) thread size (mm) amount of joint bolts Moment resistance M Rd = 1,5 * f y * W x / 1,1 = 0,192 * f y * A s 1,5 H A s thread cross-section f y = 500 MPa (rebars) f y = 640 MPa (high strength steel) N Edp Combined action N Edp / N Rd + M QEd / M Rd < 1,0 Fig. 5. Joint design before grouting
9 ANSTAR OY, Erstantie 2, FIN Villähde page Placing of bolts Minimum bolt edge distances for normal forces AHP and ALP-P bolts The bolts require only an ordinary concrete cover thickness to the surface of the concrete structure according to EC2 chapter 4. ATP, ALP-L and AMP bolts The bolt minimum edge distances are determined for the stud head anchor Minimum bolt centre to centre distances for normal forces AHP and ALP-P bolts The bolts are placed according to requirements for lap spliced rebars. ATP, ALP-L and AMP bolts Bolt minimum centre to centre distances are determined for the stud head anchors. Table 7. Minimum edge and centre to centre distances for stud head anchors Bolt Minimum distance [mm] e 1 e 2 e 3 e 4 ATP ATP ATP ATP ATP A c1 ATP ALP-L A c1 ALP22L ALP27L ALP30L ALP36L ALP39L ALP45L ALP52L ALP60L e1 e2 e 1 AMP e 2 AMP AMP AMP AMP AMP A c1 e 1 e 2 A c1 e 3 e Minimum bolt edge distances for shear force The bolt minimum edge distance for shear force is 10*Ø, if the shear force is transferred directly to concrete. If the edge distance is smaller the whole bolt shear force should be transferred using additional stirrups or U-bent rebars.
10 ANSTAR OY, Erstantie 2, FIN Villähde page Additional reinforcement Connection reinforcing principle always require reinforcement of foundation and column so, that tension, compression and shear forces can be transferred to surrounding concrete. Following chapters describe some recommended reinforcing principles Column to column joint AHP bolts join precast concrete columns with steel shoes. The reinforcement should be designed according to following instructions, see figure Bolt tension and compression forces are transferred to the column by using a single main reinforcement bar corresponding to bolt or by using two smaller main reinforcement bars, the lap length of which must correspond to the bolt length. (see table 2) 2. All shear forces are transferred with the stirrup reinforcement A qt. 3. Transverse stirrups A st must be placed in both ends of the bolt according to EC2 section These stirrups are given in table 9. AHP A qt + Ast Ast Fig. 6. Reinforcing principle for column top Placing short stud head anchor bolts in slabs or low foundations Tension load Concrete cone failure is resisted by surface reinforcement or when needed with additional bent bars A rt. Compression load if H min 5*M if H min < 5*M no additional reinforcement is needed U-links or stirrups A pt should transfer the whole action N d use AMP bolts ATP ALP-L M A rt Apt H min Fig. 7. Placing ATP or ALP-L bolts into a slab
11 ANSTAR OY, Erstantie 2, FIN Villähde page Placing short stud head anchors in a foundation column Stud head bolts can also be placed into foundation columns. The reinforcement of the columns should be designed in the following manner: 1. Tension forces acting in the bolt should be transferred to the foundation by using main rebars bent as U-stirrups, which are anchored to the slab lower surface. The anchorage length of straight rebars is not usually long enough. 2. The bolt requires stirrup reinforcement A qt in the top of the foundation column to transfer shear forces, see figure Stirrups A vt for taking splitting forces should be placed above the stud heads according to figure 8. Ordinary stirrup reinforcement should be added to this stirrup area. Fig. 8. Placing ATP or ALP-L bolts in a foundation column ATP ALP-L A qt A vt Table 8. Splitting stirrups A vt for short bolts and additional stirrups A st for long bolts Bolt Splitting stirrups Bolt Additional stirrups A vt example A st example ATP16 19 mm² 1T8 AHP16 70 mm² 2T8 ATP20 29 mm² 1T8 AHP mm² 3T6 ATP24 40 mm² 1T8 AHP mm² 4T8 ATP30 67 mm² 2T8 AHP mm² 5T8 ATP mm² 3T8 AHP mm² 5T10 ALP22L 51 mm² 1T8 ALP22P 60 mm² 2T8 ALP27L 76 mm² 2T8 ALP27P 101 mm² 3T8 ALP30L 88 mm² 2T8 ALP30P 101 mm² 3T8 ALP36L 135 mm² 3T8 ALP36P 101 mm² 3T8 ALP39L 161 mm² 4T8 ALP39P 157 mm² 4T8 ALP45L 216 mm² 6T8 ALP45P 157 mm² 4T8 ALP52L 290 mm² 6T8 ALP52P 245 mm² 5T8 ALP60L 386 mm² 5T10 ALP60P 402 mm² 6T Placing rebar bolts in a foundation column AHP and ALP-P anchor bolts can be placed in foundation columns where there is enough height. Tension forces acting in the bolts are transferred to the foundation with main rebars, which are anchored to lower surface of foundation. The reinforcement is placed in the following way, see figure 9. AHP: The anchorage length of the AHP bolts have been determined so, that straight rebars with same size placed in the column corners transfer the bolt loads. ALP-P: ALP-P bolts are anchored for full tension force with rebars of the same size as in the bolt. If rebars with larger diameters than the bolt anchor bars are used the lap length should be checked.
12 ANSTAR OY, Erstantie 2, FIN Villähde page 12 To transfer bolt shear forces a stirrup reinforcement A qt should be placed in top of the foundation column. Addition stirrups A st should be placed in the lap ends, see table 8. ALP-P A qt + A st A st Fig. 9. Placing ALP-P bolts in a foundation column Placing AMP bolts in a column AMP anchor bolts have been designed for moment stiff connection between precast beam and column. The rectangular anchor plate transfers compression loads to the concrete on front side of the column. The stud heads transfer tension loads to the opposite side. The longer side of the anchor plate is placed vertically in the column, this way the bolt can be placed close to the column edge. H Tension zone B Reinforcement for shear forces L A E ET D K Compression zone F F Fig. 10. Placing AMP bolts in a column Table 9. Minimum bolt distances in a rigid column-to-beam connection Bolt A F L D K E ET H min B min mm mm mm mm mm mm mm mm mm AET AMP AMP AMP AMP AMP A = Bolt distance from bracket F = Minimum edge distance to column side L = Total length D = Embedment length into column K = Length of visible thread E = Distance from surface of beam assembly plates ET = Minimum concrete cover for stud head H = Minimum rectangular column height B = Minimum rectangular column width
13 ANSTAR OY, Erstantie 2, FIN Villähde page Additional clauses for T40 rebar The bolt AHP39 based on rebar T40 concrete bond can be used in following conditions (EC2 chapter 8.8): 1. Use bundled rebars 2T32 or 3T25 in lap joints or consider a lower stress level. 2. Stirrups are always used as confining reinforcement 3. Additional reinforcement and crack control must be considered in each case. 4.6 Correction of capacity values Change of concrete strength The capacity values of the anchor bolts can be corrected in relation to concrete grade in the following way: Normal force capacity For lower concrete grade C20/25 the capacities should be corrected by multiplying with 0,83. Instead of reducing capacities for AHP bolts with Lmin you can choose a longer stock size bolt, e.g. AHP Shear force capacity Bolt shear force capacities can be modified for both lower and higher concrete grades than C25/30 with correction factor n: n = f ck / 25 where f ck is the characteristic compressive cylinder strength for concrete used Small edge distance If ATP, ALP-L and AMP bolts are placed closer to the structure s edge than required in section 4.2, the bolt capacity values should be reduced in the following manner. Normal force With minimum edge distance the bolt normal force capacity is taken as 100. When bolt centre is at the edge of the structure this value is 0. Any values in between can be linearly interpolated. The bolt may not be placed closer to edge than concrete cover required for stud head. Shear force The use of full bolt shear capacity requires a minimum edge distance 10*Ø. If a smaller edge distance is used, all shear forces should be transferred to concrete by stirrups. With adequate reinforcement there is no need to reduce the bolt shear capacity Small centre to centre distance If ATP, ALP-L and AMP bolts are placed closer to each other than the required minimum centre to centre distance, the bolt capacity values should be reduced in the following manner: Normal force With minimum distance from each other the combined tension capacity is taken as 100. When the bolt centres overlap this value is 50. Any values in between can be linearly interpolated. Shear force There is no need for correction. All shear forces are anchored with stirrup reinforcement.
14 ANSTAR OY, Erstantie 2, FIN Villähde page Durability and concrete cover The durability of the concrete joint with anchor bolt and steel shoe is designed according to EC2 chapter 4. The same exposure class is chosen for joint as for column and foundation structure if there is no special need to use a higher class. Check structural fire design when needed. Concrete cover of anchors The nominal concrete cover of anchor bars and anchor plates are determined according to exposure class related to environmental conditions. Concrete cover of threads The concrete cover and protection of threaded part including nuts and washers is determined according to exposure class: Exposure class X0 - In dry and warm conditions visible steel parts are painted if they can be maintained later. - Without maintainability the steel parts are covered with a required concrete cover. Exposure classes XC1 and XC3 - All bolt parts are covered with a required concrete layer and the leakage of water into the connection is prevented by structural solutions. - In cold and humid conditions bolts are hot-dip galvanized. Exposure classes XC2, XD4, XD, XS and XF - The use of anchor bolts in these environmental conditions should always be checked. The steel parts must in all circumstances be covered with a non cracking concrete layer. The leakage of water into the connection has to be prevented by structural solutions. 5 INSTALLATION 5.1 Forming a bolt group The anchor bolts are concreted into a bolt group by using an AAK assembly frame. With the frame it is easy to secure the right bolt positions, it also protects the threads during concrete casting. A rectangular assembly frame with four bolts can be ordered by using product code AAK-M- H*B, where M is thread size and H*B are bolt centre to centre distances. H B Fig 11. AAK assembly frame
15 ANSTAR OY, Erstantie 2, FIN Villähde page Bolt assembly and tolerances When using APK column shoes the anchor bolts should be assembled in the foundation concrete according to height levels given in figure 12 and table 10. Also in other applications the bolt height levels may not differ more than the allowable tolerance, so that full bolt capacities can be used. Table 10. Bolt height levels with APK steel shoes Bolt corresponding A G torque size column shoe mm mm Nm AHP16 APK AHP20 APK AHP24 APK AHP30 APK AHP39 AK ALP22 APK ALP27 APK ALP30 APK ALP36 APK ALP39 APK ALP45 APK ALP52 APK ALP60 APK A G Fig 12. Bolt height level A = Bolt height level from concrete E = Grouting thickness under column The bolts are cast into concrete with following tolerances: Height tolerance ± 20 mm Maximum allowable bolt inclination L/100 Bolt hole clearance in column shoe M16-M30 ± 5 mm M36-M60 ± 7 mm When assembly tolerances are exceeded please ask further instructions from project s structural designer. 5.3 Bending and welding of bolts When needed, straight rebars can be bended at site (not the threaded part). When bending rebars the requirements concerning bending radius and working temperatures should be followed. Lap lengths to main reinforcement should be checked for the bent bolt. It is recommended that no load carrying fixings are welded to the rebars without consulting the structural designer. 5.4 Column installation Column installation is started by levelling the upper surface of lower washers to correspond to the planned bottom level of the precast column. The column is lifted to its place and the upper nuts are tightened. The column is levelled into an upright position by adjusting the bolt nuts. The nut housings have been designed for DIN 7444 slugging wrenches. Tightening torque values are given in table 11. The values correspond to 40 % of rebar and 20 % of high strength steel bar yield strength. The bolts are locked with double nut or by breaking the thread above the nut. The given torque is not enough for cyclic compressiontension loaded bolts.
16 ANSTAR OY, Erstantie 2, FIN Villähde page 16 The grouting of the column shoe and the nut housings is done according to grout manufacturer s instructions. The grout concrete should be non-shrinking and correspond to the column concrete strength. 5.5 Safety precautions The anchor bolt threads are to be protected during and after concrete casting. The bolts may not be loaded before the concrete has achieved its design strength if the plans do not specify anything else. When installing columns the working order and the assembly supporting plan should be followed. Grouting of the connection should be done according to the installation schedule and the grouting concrete should reach the planned strength before upper structures can be assembled onto the column. 5.6 Installation control Instructions for bolt assembly Before casting ensure that bolt and frame according to plan (type, dimensions) are used and that steel parts are not damaged ensure that the bolt group position in the formwork corresponds to given tolerances ensure that bolt height level corresponds to given tolerances ensure that the additional reinforcement has been installed see that the bolt group is tightly fixed to formwork see that the bolt threads are protected until column installation. After casting check that bolt positions are in accordance with given tolerances write a measurement report Instructions for column installation The column erection is done according to designer s installation plan. The assembly controller should check the following: installation order supports and bracings during installation tightening of nuts joint grouting schedule and grouting instructions