The complete high strength friction grip principle. Advantages of high strength bolts high strength friction grip. What is the difference between normal bolts and high. The guidelines for use of high strength friction grip bolts hsfg on bridges on indian railways was issued in june2012. The frictional resistance is effective outside the hole and therefore lesser load is transmitted through the net section. They consist of fasteners that capture and join other parts, and are secured with the mating of screw threads there are two main types of bolted joint designs. Those requirements are similar to those for the hsfg bolts that have been used in. Bs 439511969 metric high strength large hexagon head bolts. The bolts are tightened to a shank tension so that the transverse load across the joint is resisted by the friction between the plated rather than the bolt shanks shear strength. These bolts should be tightened to their proof loads and require hardened washers to distribute the load under the bolt heads. High strength friction grip bolts and nuts are made from highergrade steel, and are torqued to transfer loads by friction between the steel members. High strength structural bolts high strength friction grip. What is the difference between normal bolts and high friction. The use of hsfg boltsnutswashers in structural steel works.
Quickly find suppliers of screws, bolts, fasteners and fixing elements listed by productcategory. Higher grade bolts and nuts and general trade washers 2. A highstrength bolt which is tightened with a calibrated torsion wrench. Due to the tension in the bolt, the interface between the plies steel members in a joint cannot move relative to each other because of the friction resistance. They normally consist of high tensile strength bolts and nuts with washers. Advantages of high strength bolts high strength friction. To view the content of other pages click on the transfer. High strength friction grip bolts and nuts kwikfast. Hsfg friction grip bolts and nuts high strength friction.
Specification for structural joints using astm a325 or. Are washers necessary for proper operation of bolts. These bolts rely on the shear resistance of the bolt and the bearing resistance of the connected plates to establish the load path. Research design and standards organization, lucknow.
This can be either a manual wrench or power tool fitted with a torque cutout that must. There has been need to modify certain provisions to ensure smooth. High strength friction grip fasteners hex bolts with large. Frictiongrip bolt article about frictiongrip bolt by the. In this video i have explained the shear capacity of high strength friction grip hsfg bolts along with one solved example. Bolts which are of high tensile strength used in conjunction with high strength nuts and hardened steel washers in structural steelwork. Aug 11, 2015 we are the manufacturer of high tensile bolts in india. Full list of suppliers of high strength friction grip fasteners worldwide. The term high strength friction grip bolts relates to bolts of high tensle steel, used in conjunct10n with high tensile steel nuts and hardened steel washers, which are tightened to a predetermined shank tension in order that the clamping force thus provided will transfer loads in the connected members by friction between the parts. High strength structural assemblies for preloading these were previously referred to as high strength friction grip bolts hsfg. High strength friction grip bolts and nuts tubecon. Steel washers of hard steel or carburized steel are provided as shown in fig1.
With the help of our indepth domain proficiency, we are occupied in offering our valuable clientele a broad range of high strengthfriction grip bolts. Pdf according to nzs 3404, high strength friction grip hsfg. Because of the clamping action, load is transmitted by friction only and the bolts are not subjected to shear and bearing. We are the manufacturer of high tensile bolts in india. Unbrako high strength structural bolts, nuts and washers in friction grip joints.
Research design and standards organization, lucknow report no. The basic rules for their use are laid out in bs 4604 and bs 5950, by the steel construction institute sci and the british constructional steelwork association bcsa, and the developing european structural standards. Bolted connections i version ii 33 5 high strength friction grip bolts hsfg provide extremely efficient connections and perform well under fluctuatingfatigue load conditions. All bsi british standards available online in electronic and print formats. Guidelines for use of high strength friction grip hsfg. Specification for structural joints using astm a325 or a490 bolts. What are the advantages of using high strength friction grip. Traditionally such connections have been known in the uk as high strength friction grip hsfg connections. The international standards organisation designation for bolts, also followed in india, is given by grade x. One option for substitute for rivets, namely high strength friction grip hsfg bolts is covered in these guidelines. Dimensions in the nominal size range 16 mm to 33 mm inclusive and mechanical properties are specified with details of tests, inspection procedure and marking. Pdf determination of the required partturn of the nut with. If the link fails, the document cannot be downloaded, please click on the broken link to let us know. Highest grade friction grip hsfg bolt loading capacities.
Pdf the high strength friction grip property class 8. Bs43951 specification for high strength friction grip bolts and associated nuts and washers for structural engineering. The free encyclopedia for uk steel construction information. Bs43951 specification for high strength friction grip. Isi handbook for structural engineers part 4 use of high strength friction grip bolts number of amendments. The tensile stress area a t is obtained from standards.
The main advantages of hsfg bolted connections are their greater stiffness and. When the joint is assembled the contact surfaces must be free from dust, oil. General grade includes all amendments and changes through reaffirmation notice, february 2007. Their high strength is achieved through quenching and tempering processes or by alloying steel. Manufacturer of high strength structural bolts high strength friction grip bolt, high strength structural bolt, astm a325 nut and astm a325 bolt offered by dadu precision fasteners private limited, bhiwadi, rajasthan. General grade frictiongrip bolts, bolts, nuts, threaded fasteners, threaded components, washers, hexagonalhead fasteners, construction systems parts, hightensile steels, steels, chemical composition, sampling methods, dimensions, threads, thread pitch, chamfered. The european law 20096ce regulates the use of cookies. In this nomenclature, x indicates onetenth of the minimum ultimate tensile strength of the bolt in. Research design and standards organization, lucknow report. Unit 3, crittall road, witham, essex, cm8 3dr main sales. In the uk, the use of tcbs as friction grip bolts gives rise to difficulties in. General grade friction grip bolts, bolts, nuts, threaded fasteners, threaded components, washers, hexagonalhead fasteners, construction systems parts, high tensile steels, steels, chemical composition, sampling methods, dimensions, threads, thread pitch, chamfered.
Highstrength structural bolting assemblies for preloading part 8. Bolts which transfer load by friction are known as high strength friction grip. What is the difference between normal bolts and high friction grip bolts. The improved and complete instruction manual for installing. High frictional resistances is developed providing a high static strength the joint. Highstrength structural bolting assemblies for licensed.
Specification for structural joints using highstrength bolts. Specification for structural joints using astm a325 or a490 bolts, june 23, 2000. Tension control bolts, grade s10t, in friction grip connections. The bolts are tightened to a shank tension so that the transverse load across the joint is resisted by the friction between. General grade amd 1841 amd 2198 withdrawn publication year 1969 document status. Hsfg bolts what you need to know about hsfg standards. Variability of installed tension and potential resulting effects on the frictiontype connections behaviour conference paper pdf. Here is some useful information relating to high strength friction grip bolts. It is important to ensure that these bolts are correctly used if satisfactory results are to be obtained. Hsfg bolts are high strength structural bolts which have been tightened such as to induce predefined tension in the bolt shank. Recommendations giving guidance in the use of this form of fastener are given in bs 46041. The bolts are tightened to a specified minimum shank tension so that transverse loads are transferred across the joint by friction between.
For the direct tension calibration, the bolts were tested in a universal. Hsfg bolts high strength friction grip they make use of friction. High strength friction grip bolts hsfg bolts are high strength structural bolts which have been tightened such as to induce tension in the bolt shank. The length of free thread above the nut or adaptor between nut or adaptor and head of bolt shall be between half and one 4395. Frictiongrip bolt article about frictiongrip bolt by. Once tightened, the bolts will remain tight and maintain the permanent strength of the joint. Since that time the council has published fourteen successive editions.
High strength structural fasteners in friction grip joints are ideal for use on timebound projects. Bolted joints are one of the most common elements in construction and machine design. Impala bolt and nut high strength friction grip bolts. Manufacturer of high strength structural bolts high strength friction grip bolt, high strength structural bolt, astm a325 nut and astm a325 bolt offered by dadu. Guidelines for use of high strength friction grip hsfg bolts on bridges on indian railways 1. High strength friction grip hsfg bolts are well established as economical and efficient devices for connecting structural steel. The extension of the bolt shall be measured, at its true centre line, with a suitable instrument.
Through finite element analysis fea and experimental study, the mechanical behavior including slipload. Defines requirements for the use of high strength friction grip bolts of the general grade, as specified in bs 43951, in friction grip connections in structural steelwork which complies with the requirements of bs 4492. This is a new field for indian railways and lots of issues have been raised by the users, designers and field engineers. Since the bolts were tested at the same grip as existed7in the joint, the loadelongation curves obtained from the torque. High strength structural bolts high strength friction. Highstrength structural bolting assemblies for licensed copy. Over the conventional methods of riveting or welding, they offer the followingadvantages.
The introduction of high strength steels has increased the types and grades of bolt available to the designer. Specification for structural joints using highstrength bolts december 31, 2009 supersedes the june 30, 2004 specification for structural joints using astm a325 or a490 bolts. Assembly of structural joints using high tensile steel bolts, was published in january 1951. High strength friction grip hsfg bolts design of steel. Bs 460411970 specification for the use of high strength friction grip bolts in structural steelwork metric series part1 general. Care should be taken that the specified bolts and nuts are not mixed with ungraded bolts that may be on site for other purposes. High strength bolted friction grip hsfg joints are widely used in steel bridges. Jul 12, 2017 in this video i have explained the shear capacity of high strength friction grip hsfg bolts along with one solved example. High strength friction grip bolts sometimes abbreviated to hsfg bolts. Highstrength structural bolting assemblies for preloading. Hsfg supports the weight by clamping the plates so tightly together. Is it desirable to use concrete of very high strength i. Prepared by rcsc committee 15specifications and approved by the research council on structural connections. Approximate masses of ordinary bolts, nuts and washers.
Use of high strength friction grip bolts in structural steelwork. The free unloaded bolt threaded portion beyond the nut is the only part of. Preloaded bolts are seldom used in buildings, where fatigue and slip in service are less critical. Pdf finite element analysis and experimental study on. What are the differences between rock dowels and rock bolts. Select a product to see suppliers, manufacturers, distributors, technical data for high strength friction grip fasteners, hex bolts with large width across flats for high strength strctural bolting, hex nuts for high strength structural bolting, plain washers for steel sctructures chamfered, square. Supersedes the june 3, 1994lrfd specification for structural joints using astm a325 or a490 bolts and the june 3, 1994 asd specification for structural joints using astm a325 or a490 bolts. This handbook is based on and requires reference to the following publications issued by lsi. However, they may be used where oversized or slotted holes are used to increase tolerances during assembly. The use of high strength structural fasteners in friction grip joints has. A high strength bolt which is tightened with a calibrated torsion wrench.
Determination of the required partturn of the nut with respect to the number of free threads under the loaded face of the nut in fully tensioned high strength friction grip property class 8. Hsfg stands for high strength friction grip also hamburger sozialforschungsgesellschaft e. The use of international standards that affect the design of. High strength bolt these bolts are called friction grip bolts. Effect of surface coatings and exposure on slip behavior of bolted joints james h. High strength friction grip fasteners hex bolts with. What are the advantages of using high strength friction. Do inclined rock bolts perform better than rock bolts normal to joints. Legally binding document step out from the old to the newjawaharlal nehru invent a new india using knowledge. Direct tension and torque tension calibrations were performed on each lot of bolts.