The report summarizes an investigation of the behavior of bearing stiffeners for corrugated web igirders, and. In angular contact bearings the external forces f act. Stiffener layout design for plate structures by growing. Additionally to en 199315 design rules a simplified design procedure for transverse stiffeners is proposed that includes second order effects and all relevant loadings. All the standard hotrolled shapes in the manual, the webs are compact. The contact lines are the generatrices of the pressure cone apex. For plate girders, bearing stiffeners are required to be placed on the webs at all bearing locations and at all locations supporting concentrated loads.
Or see table 1 for web stiffener size requirements approx. Stiffener requirements for plate girders, ms thesis. Therefore the scope of work area 4 covers corrugated web girder bearing stiffeners and field splices. Lrfd steel girder superstructure design example miscellaneous steel design example design step 5 table of contents design step 5.
Girder strength could be substantially increased by the r use of stiffeners. From the inspiration of branching systems in nature, this paper suggests a new and direct topology optimization method for the generation of stiffener layout patterns for plate structures by introducing the growing and branching tree model. Click on a datetime to view the file as it appeared at that time. In the calculation of the stressed area, the load may be assumed distributed over the distance. Other bearing designs are often better on one specific attribute, but worse in. If k12 and k are satisfied, and r is in compression, stiffeners must be provided to prevent local web. Requirements on the tribological properties and the knowledge of influences by the bearing environment help to select the proper norglidematerial. Transverse stiffeners must satisfy stiffness and strength requirements. The details of an end bearing stiffener are shown in figure p10. When flanges or moment connection plates for end connections of.
The width of each stiffener plus half the thickness of the column web should not be less than onethird the width of the flange or momentconnection plate delivering the concentrated force. Rolling element bearing stiffness matrix determination. There is no analytical solution giving the bearing stiffness. The fluid lubricant forms a film between the sliding surfaces so that there is no contact between solid components. This model captures the timedependent characteristics of t\ he bearing contact due to the orbital motion of the rolling elements. Design and behavior of bearing stiffeners and splice plates used for corrugated web girders by tameka clarke a thesis presented to the graduate and research committee. These checks relate specifically to the design of column web doubler plates or transverse stiffeners for the column flange also known as continuity plates. Lusas user manual, 1986, finite element analysis ltd.
An explanation of plate girder design in the lrfd specification will include. Having decided that bearing stiffeners are to be provided, to verify the design of bearing stiffeners, determine the effective stiffener section in accordance with en 199315 clause 9. Compressive bearing stiffeners are to be provided in pairs and be full depth of the member. Bearing stiffness calculation is usually done using an iterative algorithm such as newtonraphson, because the contact angle depends on the loading. Transverse web stiffeners and shear moment interaction for. The in uence of bearing sti ness on the vibration properties of statically overdetermined gearboxes m. Apr 10, 2016 restraint against torsional rotation at supports in these beams can be provided by web or flange cleats or bearing stiffeners acting in conjunction with the bearing of the beam or lateral end frames or external supports providng lateral restraint to the compression flanges at the ends, or they can be built into walls 49. The aisi and csa design documents require a bearing stiffener when ht of the web of a flexural member exceeds 200, and design provisions are provided.
Design should be made for compression force due to bearing and moment. Journal bearing design, lubrication and operation for enhanced performance gregory f simmons issn. However, there are some practical problems with the current requirements. Rn, local lateral bracing shall be provided at the tension flange or either a pair of transverse stiffeners or a doubler plate, extending at least onehalf the depth of the web, shall be provided adjacent to the concentrated.
However, the recommendations of this design guide are based on. Bearing stiffeners the details of an end bearing stiff. The primary reference for the design of these stiffeners is aisc design guide. The rules for stiffener design in en 199315 are thus no longer consistent with the rotated stress field theory and lead to a greater. Probabilistic analyses are performed to calculate the mean, standard deviation and probability density function of the bearing performance measures. A sliding bearing typically uses a lubricant to reduce friction between the sliding surfaces. Chanical power transmission, antifriction bearing design. Tapered roller bearings can withstand high accelerations and decelerations. Based on extensive fem simulations, criteria for preventing undesirable. Roller bearing design pdf the roller bearing part numbering system is designed to identify the important basic features of the bear ing while providing a unique part number. They are differentiated by the applied load and the location of the gap between the slightly undersized stiffener and the top or bottom flange.
In design of bearing, the initial value of k is chosen to be. Bearing is defined by websters to be a support or supporting part a bearing is a component that allows for relative motion between parts your skeleton is the central structure that supports your body your bodys joints are bearings that allow different parts to move bearings can have many forms, but only two types. Note that multileg stiffeners must be split into separate effective cross sections and the loads divided between them. The bearing resistance is limited by crushing of the concrete hawkins, 1968a,b. Performing organization name and address hdr engineering, inc. Design of bearing stiffeners mcgrawhill education access. End post and load bearing stiffeners shape, size and thickness end post and load bearing stiffener minimum requirements design as a load bearing column. Current theoretical bearing models differ in their stiffness estimates because of different model assumptions. Thus, the contact between ball and race is of finite size and has finite pressure. A stud or track section as a bearing stiffener will be. This condition is not met by any of the bearing stiffeners in common use today. Aug 29, 2017 plummer block or pedestal bearing it is a split type of bearing.
Web stiffeners in plate girders have been designed successfully for more than 100 years. At end supports, if bearing stiffeners are to be provided, then a decision has to be made as to whether to provide a rigid end post, as shown in en 199315, figures 5. Transverse stiffeners for compressive concentrated loads. However, the design bases and assumptions according to different codes and proposals differ widely, and this has an important effect on web thicknesspanel size optimisation, and hence on the weight of the stiffened web. The basis of current design formulations for transverse stiffeners are compared with the.
If necessary, the pivot point has to be modified accordingly. The influence of bearing stiffness on the vibration. This design example is targeted at bridge owners and bridge engineers who have been tasked with. Practically, the mating or contact surface can be made of any steel or plastic. Design and behavior of bearing stiffeners and splice plates. Stiffener requirements for plate girders, june 1968. For the case of compressive concentrated loads, the bearing stiffeners and beam web are treated as built up columns. The effective section of the transverse stiffener includes an effective width of plate equal to 30et. A practical guide for solving vibration problems in bearings pdf file for free from our online. This type of bearing is used for higher speeds, heavy loads and large sizes.
Design of bearing stiffeners in cold formed steel csections. Design of crankshaft main bearings under uncertainty. Aerospace design guide 6 aerospace design guide frequently supplied with integral gears on their outer rings, spherical roller bearings are the preferred choice when operating conditions include heavy loads and difficulties with housing alignment or shaft deflection. Steel bridge design handbook bearing design volume 15.
Cast iron pedestal or block with a sole brass or gunmetal or phosphorusbronze brasses, bushes or steps made in two halves. Bearing stiffeners are required to resist the bearing reactions and other concentrated loads, either in the final state or during construction. Aashto manual for condition evaluation of bridges, section 6. Bearing stiffeners and field splices for corrugated web. When a beam or column is supported by concrete or masonry, or. Plummer block or pedestal bearing it is a split type of bearing. This means that no element in the stiffener can be subject to effective width reductions up to the design stress level. Sep 16, 2014 a simple way to estimate bearing stiffness, machine design, vol. The purpose of this paper is to provide with an analytical expression of ball bearing stiffness, for a preloaded paired bearing.
The pressure cone apex is that point on the bearing axis where the contact lines of an angular contact bearing, i. Bearing plates are used to transfer concentrated compressive forces between two structural elements. Design of stiffeners in eurocode 3 part bridge engineering. A rigid end post will benefit the shear resistance as calculated by en 199315 clause 5. The design requirements for these stiffeners is found in scm j10. Bearing stiffeners are required in a plate girder when a concentrated load, applied to either the top or bottom flange, exceeds the local yielding, crippling. Check bearing stiffener requirement webs with concentarted forces when the required strength of the web exceeds. Situations when bearing stiffeners are required see figure asd01. The growth technique begins with the growing of ground baby stiffeners around a given set of seeds.
When a beam supports are large concentrated load from a supported element, such as a column. A shaft and bushing bearing is known as a journal bearing. Finite element analysis fea of the stressstrain state. Bolte zar faculty of mechanical engineering, university of ljubljana, a sker ceva 6, ljubljana, slovenia. The goal of this study is to evaluate a tapered roller bearing that supports the differential housing of an automotive manual transmission. The clearance of all main bearings and the oil viscosity comprise the random design variables.
Plate girder shear and flexural strengthening design. There are two basic design criteria for bearing stiffeners. Pren 19931 design of concrete structures and pren 19931 design of steel structures, solve the same problem of the bearing resistance of concrete loaded by a steel plate. Simple and versatile dynamic model of spherical roller bearing. Lrfd steel girder superstructure design example lrfd.
Design and behavior of bearing stiffeners and splice plates used for corrugated web girders tameka clarke. In this study, a finite elementcontact mechanics model is developed for rolling element bearings with the focus of obtaining accurate bearing s\ tiffness for a wide range of bearing types and parameters. Stiffeners form prompts the user for information that is represented by the following input items. A reliabilitybased design optimization rbdo study is also. A numerical method is developed to determine the full bearing stiffness matrix corresponding to two radial, one axial, and two angular coordinates. A simple way to estimate bearing stiffness, machine design, vol. This kind of bearings are known as fluid film bearings. Design to ec3 part 15 nanyang technological university. Stiffeners required by the preceding equations should comply with the following additional criteria.
Design and behavior of bearing stiffeners and splice. Design of stiffeners under loads as per aisc guidelines, the combined effect of forces from moment and shear should be considered while designing fasteners or welds for end connections of girders, beams, and trusses. Bearings catalogs and cad drawings services nsk global. Two types of stiffeners are commonly used, namely, transverse vertical stiffeners and longitudinal horizontal stiffeners. For a rolled beam, bearing stiffeners are required at a concentrated load if the stress f a, ksi mpa, at the toe of the web fillet exceeds f a 0. Intermediate stiffeners shape, size and thickness intermediate stiffener general requirements effective cross section direct and shear stress verifications end post and load bearing stiffeners shape, size and thickness end post and load bearing stiffener minimum requirements design as a load bearing column. Although older riveted girders in the uk may have a rigid end post end detail, more recent uk practice has not.
Restraint against torsional rotation at supports in these beams can be provided by web or flange cleats or bearing stiffeners acting in conjunction with the bearing of the beam or lateral end frames or external supports providng lateral restraint to the compression flanges at the ends, or they can be built into walls 49. The resistance of the effective crosssection of the load bearing stiffener should also be checked at a position close to the loaded flange. R n, local lateral bracing shall be provided at the tension flange or either a pair of transverse stiffeners or a doubler plate, extending at least. Plate girder design using lrfd university of maryland.
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