2016 8 27 nbsp 0183 32 rigidity of joints no slip in service no loosening of bolts due to vibrations better fatigue performance tolerance for fabrication erection because of the use of clearance holes familiarity within industry With minimal disadvantages disadvantages quoted by some designers are difficulty of ensuring that all bolts are adequately pre loaded 2002 8 30 nbsp 0183 32 Anchor rods may be configured to provide anchorage into concrete by means of a head threading with a nut on the end a hook or by swaging The term anchor bolt when used with ASTM A307 grade C A325 or A490 material however only describes the first option for the following reasons These specifications include heading requirements for galvanized non pretensioned anchor rods corresponds to detail ategory E however the fatigue threshold is much greater than other ategory E details Therefore in the case of anchor rods a threshold of 13 lightpolebase com 7000 psi is recommended per Anchor bolts repair and replacement More often anchor bolts break from too little tightening than too much We fix broken and loosened anchor bolts couple them with new sections or if necessary replace them with new proper ones We check the material strength of the bolts and the specified torque to ensure that the fastening load of Multiple types of truss brackets of unique design are incorporated in the various systems which also include tensioning tie rods and anchor bolts The truss bracket components are designed so that a minimum or no force couples are exhibited when the tie rods employed are tightened down in their interconnection between associated truss brackets

Accepted procedures for fully tensioning high strength bolts can be found in the RCSC Specification Section 8 2 see also 6 6 3 If torque is to be used as in the calibrated wrench method as described in the RCSC Specification Section 8 2 2 it must be calibrated on a daily basis for the lot diameter and condition of bolts being installed for anchor rods The ASTM F1554 anchor rods are available in three grades of 36 55 and 105 ksi minimum yield stress material and are available in specified lengths with threading lengths as specified ASTM A449 is a general material standard that is2012 3 9 nbsp 0183 32 From API 686 Recommended Practices for Machinery Installation and Installation Design 2009 Annex B Table B 1 it uses pretension stress 30ksi almost 70 of ASTM F1554 Grade 36 A307 or A36 anchor rod material capacity phi futa 0 75 58ksi 43 5ksianchor rod setting procedures and tolerances The impor tance of the accurate placement of anchor rods cannot be over emphasized This is the one of the key components to safely erecting and accurately plumbing the building The material in this Guide is2021 2 12 nbsp 0183 32 Pretensioning the rod can improve it s fatigue life but anchor rods can effectively be pretensioned only against steel Even when tensioning 55 ksi rod 24 in long it only takes concrete creep shrinkage of 0 05 in to relieve all pretension

Example Red Bull Arena in Leipzig 320 BESISTA M45 and M68 tension rods were pretensioned at a height of up to 56m at low cost in a short time and without incident The cross members are assembled and secured 2004 11 19 nbsp 0183 32 A325 is not an appropriate material for anchors Properly use A307 A36 or F1554 These would probably not be pretensioned Properly designed anchor bolts need to be embedded adequately into the concrete quot Adequately embedded quot means that the anchorage will not fail before the anchor bolt material itself fails L Incline length of cone V Volume of cone right angle cone 1 3 R 178 h S Rock shear resistance multiplied by the rock cone interface surface area FS Factor of Safety 5 for a 2 1 Safety Factor Y Unit Weight of rock approx 150 pcf dry U Ultimate tensile strength of anchor rod O Cone Angle View Applications of Pretensioned Anchor Rods in Industrial Facilities pdf from CIVE 3337 at University of Houston 9 5 5 59 161 4 5 53 357211863 BECHTEL Engineering Design Guide Vibration Sensitive Structures pdf University of Houston CIVEThis paper provides a brief overview of the current state of the practice regarding pretensioned anchor rods and reviews selected recent pretensioned anchor rod applications in

Anchors and Inserts ASTM A36 structural steel plates and shapes ASTM A153 or ASTM A123 hot dipped galvanized finish Non metallic Shrinkage Resistant Grout Proprietary pre mixed non metallic non corrosive non staining product containing selected silica sands Portland cement shrinkage compensating agents plasticizing and water reducing agents complying with CRD pretensioned system after resin anchor end bent for anchor hole in Drill 1 1 4 quot 211 in end bent resin 2 Drilled anchor holes beam grout 2 Cast anchor holes in and grout installed with resin 2 Resin Anchor Systems Placement and Partial Width 8 8 SealantApplications of pretensioned anchor rods are less common and generally limited to certain industrial facilities This paper provides a brief overview of the current state of the practice regarding pretensioned anchor rods and reviews selected recent pretensioned anchor rod applications in power industry facilities If you choose to require pretensioned anchor rods you would need to define how much pretension is required how that pre tension is to be achieved and how that pretension is to be maintained against such factors as creep in the concrete and the variations in 2009 4 27 nbsp 0183 32 Pre tensioned Anchor Rods A Few Questions 1 I have seen recommendations in the past not to pre tension rods with yield strength below 60 70 Ksi I basically understand that there are concerns with pre tensioning mild steel rods but would like to see more specific information on these concerns 2

Prestressed concrete anchors are often used for resisting cyclic or dynamic loading caused by wind or seismic events They are also used to limit or restrict structural movement due to anchor steel elongation Common applications for prestressed concrete anchors are tower anchoring foundation repair and heavy machinery tie down 2019 1 17 nbsp 0183 32 Pretensioned anchorage material The materials used for making the pretensioned ancho rage specimens in this study mainly include anchor rods anchorage agents concrete steel tubes pallets nuts and steel cylinders The bolt with a diameter of 20 mm is2003 6 10 nbsp 0183 32 RE Pretensioned Anchor Rods Ingenuity Structural 10 Jun 03 20 43 I am not familar with Taro s reference quot Anchorage of Steel Building Components to Concrete quot by Marsh and Burdette AISC Engineering Journal Q1 1985 but the DIRECT addition of the pretension force and the applied external tension would be incorrect IMO anchoring system The adhesive bonds to the dust and the dust is bonded to nothing 5 Using an anchor which does not have the capacity for the job A particular anchor may be adequate on a horizontal surface but totally inadequate when used on a 6 DETAN Rod Systems are used for structural bracing tension and compression where an architectural or aesthetic quality is desired Available in high strength carbon and stainless steels DETAN has a vast range of rod diameters and lengths making it suitable for limitless applications Engineering support provided throughout the design phase

Tags: