Investigating the performance of isolation systems in. It was invented by william robinson, a new zealander. The second type of elastomeric bearings is lead rubber bearings lrb. The typical hysteresis loop of a lead rubber bearing can be modelled as bilinear. Both dynamic and static friction coefficients are estimated with high accuracy by utilizing a newly proposed effective surface pressure. Effectiveness of lead rubber base isolators, for seismic. As discussed on page 1029, the surface finish is critical. Techstar offers a wide range of products that accommodate these movements and loads and maximize the performance of the bridge structure. Fundamentals of the recycling of leadacid batteries therefore, recyclers have to be aware that batteries in hard rubber casing and pvcseparator will come in with battery scrap. The paper focuses on the investigation of application of lead rubber bearings lrbs instead of pot bearings in a new kutai kartanegara steel arch bridge located in east kalimantan province. In story 1 of model 2 the point displacement in xx direction is increased by 87% when compared to model 1, in story 6 of.
The shearstrain amplitudes of the testing were 1%, 10%, 20%, and the maximum number of the cycles for each level of amplitude was 4000000, 59000, and 17000, respectively. The performance of the hesarak bridge constructed in karaj city, iran with two isolation systems. Rubber bearing type linksupport element is used to model nonlinear behavior of lead rubber bearing in this study. A comprehensive methodology for the design of leadrubber isolation bearing has been proposed and discussed in detail. This paper presents the design methodology of lead rubber bearing used for seismic isolation of bridges. Dynamic properties of lead rubber bearings and its seismic. Seismic base isolation, also known as base isolation or base isolation system, is one of the most popular means of protecting a structure against earthquake forces. Maurer lead rubber bearings mlrb are devices for seismic isolation, see brochure maurer earthquake protection systems, pages 10 and 11. To illustrate this, a design of leadrubber bearing at abutments and piers of a three span bridge has been included. A wide variety of lead rubber bearing options are available to you, there are 1,143 suppliers who sells lead rubber bearing on, mainly located in asia. The seismic response analyses of piers isolated by lrb in axial direction of the bridge are carried out under the excitations of seven earthquake waves.
A steel column is subjected to a combination of loads only the main axial load university of washington, seattle cee 220 spring 2017. Modeling of lead rubber bearings via 3d basis, sap2000. Lead rubber bearing or lrb is a type of base isolation employing a heavy damping. It is very soft laterally but very stiff vertically. Seismic study of application of lead rubber bearings in. Robinson wh, tucker ag 1983 test results for leadrubber bearings for the william m. Depending on the type of battery, its size and design, the material composition of a starter battery varies. For one of the test configurations, the building was seismically isolated by a hybrid system of lead. The lead core can not only bear the heavy load and horizontal force, but also absorb energy through plastic deformation of hysteresis damping.
The frictional devices are classified into three types. Lead rubber bearing lrb system to a stochastic earthquake. The top countries of suppliers are vietnam, china, and taiwan, china, from which the percentage of lead rubber bearing supply is. Dynamic isolation systems dis is the leader in the seismic isolation of bridges and buildings. They consist of a steel reinforced elastomer bearing chloroprene caoutchouc or natural caoutchouc with additional lead core. Using the minimization of the maximum energy absorption level of the upper structure subjected to an. Nuclear power plants with isolation systems require seismic probabilistic safety assessments, for which the seismic fragility of the structures, systems, and components. A lead rubber bearing is a much larger laminated bearing manufactured from layers of rubber which are sandwiched together with layers of steel and in the middle of the bearing there will be a solid lead plug.
For nonlinear rubber bearing, bilinear forcedeformation properties including. The combined system may not be desirable because two different isolator types are used in an application with only eight bearings. Clayton building, toe toe bridge, and waiotukupuna bridge. For leadcore can dissipate seismic energy and increase stiffness under load simultaneously, and most of the requirements of the seismic. Lastolrb lead rubber bearings can be used in the construction of new structures, or to enhance an existing structures strength and resistance to seismic forces. Top and bottom of the lrb is fitted with steel plates, which are used to attach bearing to building through. Effect of lead rubber bearing characteristics on the response of seismicisolated bridges article pdf available in ksce journal of civil engineering 123. Ninety percent of our isolators have an energy dissipating lead core. Vertical stiffness of elastomeric and leadrubber seismic. Under normal conditions, they function as regular deformation bearings, and are thus particularly suitable for structures with limited space availability, where the installation of. It is an important component of seismic isolation bearing. It is important that point displacements at bottom stories must be increased after providing lead rubber bearing at base.
The material property of the rubber has been studied in order to improve the reliability of the finite element model of a lead rubber bearing lrb which is a typical base isolator. No need to provide nonlinear property of isolator in rsa, it is needed in fna. The lead rubber bearings and sliding bearings are most commonly employed base isolators for buildings of medium height. Techstar products are specifically designed for each individual bridge, thus optimizing the product application. Design and characteristics of high damping natural rubber. The scientific research continues and a new how to cite this paper.
Home engineering spreadsheets lead rubber bearing properties in sap2000. This base isolation system provides the combined features of vertical load support, horizontal flexibility, restoring force, and damping in a single unit. Heavy damping mechanism incorporated in vibration control technologies and, particularly, in base isolation devices, is often considered a valuable source of suppressing vibrations thus enhancing a buildings seismic performance. Lead rubber bearing for seismic bridge and building.
They can also be purchased as specific bearing elements with features such as slit surfaces that allow them to be more easily pressed into a hole to snap in place. Research paper excel spreadsheet for design of lead rubber. Leadrubber bearings lrbs have one or more lead plugs that are inserted into holes in a lowdamping natural rubber bearing to increase the damping capacity. Instead of using traditional bearings like ptfepot bearing lrb is found to be effective in high seismic region and it is used in many developed countries. Even though the bridge is known located in seismic zone 1 the zone with the least seismic risk as per rsni 2833201x, the study was extended for other.
Base isolation of residential building using lead rubber. Bilinear model proposal for seismic analysis using triple. Studies on the application of the lead rubber bearing lrb isolation system to nuclear power plants are being carried out as one of the measures to improve seismic performance. Based on the finite element program sap2000, 120 models of eight different piers with different leadrubber bearings lrb are established. Lead rubber bearings isosism lrb the isosism lrb isolators consist of alternate layers of rubber and vulcanised reinforcement steel plates of limited thickness and a central lead core. Lead rubber bearing, also called lead core rubber bearing, lnr rubber bearing, has similar structure with high damping rubber bearing. Application of lead rubber isolation systems in the. The elastomer bearings, also referred to as deformation bearings, respond to displacements with elastic recentering forces. In chamfer recessed in rubber l bearing sc sb beveled sole plate plan section aa fixed pot bearing girder flange beveled sole plate piston brass sealing ring elastomeric disc pot. A study on the seismic isolation systems of bridges with. Fundamentals of the recycling of lead acid batteries. Lead core rubber bearings lrb lead core rubber bearings lrb consists of a laminated rubber and steel bearing with steel flange plates for mounting to the structure.
Structural isolation service high density rubber bearing. Pdf effect of lead rubber bearing characteristics on the. In this study, lead rubber isolation system is developed to mitigate the vibration of fixed jacket offshore platforms. It is beyond the ability of sap2000 to model the temperaturedependent behavior. Seismic retrofit of piers supported on battered piles. Lead rubber bearings a leadrubber bearing is formed of a lead plug forcefitted into a preformed hole in an elastomeric bearing. Dmitri kopeliovich lead based alloys are still widely used as overlay materials mainly in copper based trimetal bearings. Isolation bearings, seismic isolators, isolation in india, isolation, base isolation,seismic isolation,dynamic isolation systems,dis,konrad eriksen,bridge retrofit,historic building retrofit,earthquake. From this background, fatigue characteristics of a lead rubber bearing lrb under repeated smallamplitude were evaluated by cyclic loading tests of scaled models. Typically, the diameter of the lead core is limited to onethird of the. Lead rubber bearing lrb is a new type of earthquakeresistance rubber bearings, formed by inserting leadcore into ordinary laminated rubber bearing, vertical supporting, horizontal displacement and hysteretic damping are hung in single unit together. Optimum design of leadrubber bearing system under the non. A lead rubber bearing is formed of a lead plug force fitted into a preformed hole in an elastomeric bearing. Small displacements are absorbed by the rubber itself, while large displacements cause the rubber bearing to slide on the plate.
Large strain nonlinear model of lead rubber bearings for. Linear bearing, low damping rubber bearing, lead rubber bearing, flat sliding bearing, double and triple frictional pendulum bearings are some of the isolator types that can be modeled using the available features in sap2000. More than 250 buildings and bridges are protected from earthquakes by dis seismic isolators. This isolation system is composed of eight lead rubber bearings as isolators. Lead rubber bearing properties in sap2000 input your data in input sheet and get outputs in sap2000 sheet. Triple friction pendulum bearing element in opensees duration. Leadrubber bearings with emphasis on their implementation. Research paper excel spreadsheet for design of lead. Typical leadrubber bearing courtesy dis the energy dissipation capacity, or damping, is governed by the plastic deformation capacity of the lead core. Table 1 compares an old type of battery in hard rubber. The parameters d 1, f 1, d 2, and f 2 that define the bilinear curve are given in the following tables per each standard lrb. The lead core provides rigidity under service loads and energy dissipation under high lateral loads.
Top and bottom steel plates, thicker than the internal shims, are used to accommodate mounting hardware. In this implementation, the linear shear spring has been replaced by a bilinear spring to represent the nonlinear behavior observed in elastomeric and leadrubber bearings ryan et. Twospring model of an isolation bearing in the undeformed and deformed configuration. It is a collection of structural elements which should substantially decouple a superstructure from its substructure resting on a shaking ground thus protecting a building or nonbuilding structures integrity. All bridges are different and require special attention to the movements and loads that apply.
They allow the isolation of the structure by a proper selection of the horizontal stiffness and they can dissipate energy up to 30% damping due, to the high. The authors also observed that laminated rubber bearings. Study on the impact of leadrubber bearing parameters on. The calculations of seismic responses of the piers with and without isolation are implemented by using. This paper investigates the influence of isolation systems on the seismic behavior of urban reinforce concrete bridge.
Ideally the surface has only valleys which act to trap pools of lubricant and no peaks which act as file teeth. He earned a masters at the ardmore school of engineering, then a phd in physical metallurgy at the university of illinois. The damping ratio required at the design displacement can be achieved by adjusting the size of the lead core. It is composed of laminated rubber bearing and lead core. Products seismic isolator for buildings bridgestone. Maurer lead rubber bearings mlrb are devices for seismic isolation. Design analysis of leadrubber isolation system this case study is developed as an alternative to the combined leadrubber and elastomeric bearing isolation system constatinou, et al. Instead of using traditional bearings like ptfepot bearing lrb is found to be effective in high seismic region. We used two parameters to develop an optimization method for bearing design. Design and characteristics of high damping natural rubber bearings for base isolation.
The test results show that the torsional behavior of the lead rubber bearing component in bi. However in many applications the alloys containing toxic lead are replaced with new developed leadfree materials. Bearing is one of the important components of bridges. The performance checks and testing requirements of this type of bearings are also highlighted. The natural rubber bearings show a linear behavior in shear up to shear strains above 100%, and have damping in the range of 23% of critical. The rubber compounds normally used in the production of lrb are characterised by an effective dynamic shear modulus g. Rubber bearing,natural rubber bearings,industrial rubber. William henry robinson qso 2 october 1938 17 august 2011 was a new zealand scientist and seismic engineer who invented the lead rubber bearing seismic isolation device.
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