Top PDF Experimental Investigation of the Seismic Response of Bridge Bearings

Experimental Investigation of the Seismic Response of Bridge Bearings

Experimental Investigation of the Seismic Response of Bridge Bearings

16. Abstract The Illinois Department of Transportation (IDOT) commonly uses elastomeric bearings to accommodate thermal deformations in bridges. These bearings also present an opportunity to achieve a structural response similar to isolation during seismic events. IDOT has been developing an earthquake resisting system (ERS) to leverage the displacement capacity available at typical bearings in order to provide seismic protection to substructures of typical bridges. The research program described in this report was conducted to validate and calibrate IDOT’s current implementation of design practice for the ERS, based on experiments conducted on typical full-size bearing specimens, as well as computational models capturing full bridge response. The overall final report is divided into two volumes. This first volume describes the experimental program and presents results and conclusions obtained from the bearing and retainer tests. The experiments described in this volume provide data to characterize force-displacement relationships for common bearing types used in Illinois. The testing program comprised approximately 60 individual tests on some 26 bearing assemblies and components (i.e., retainers). The testing program included (1) Type I elastomeric bearings, consisting of a steel-reinforced elastomeric block vulcanized to a thick top plate; (2) Type II elastomeric bearings, distinct from Type I bearings with a steel bottom plate vulcanized to the bottom of the elastomeric block, and a flat sliding layer with polytetrafluoroethylene (PTFE) and stainless steel mating surfaces between the elastomer and the superstructure; and (3) low-profile fixed bearings. Tests conducted to simulate transverse bridge motion also included stiffened L-shaped retainers, consistent with standard IDOT practice. Tests were conducted using monotonic and cyclic displacement protocols, at compression loads corresponding to a range of elastomer compression stresses from 200 to 800 psi. Peak displacements from initial position ranged from 7-1/2 in. to 12-1/2 in., depending on bearing size. Test rates were generally quasi-static, but increased velocities up to 4 in./sec were used for bearings with PTFE and for a subset of other elastomeric bearings. On the basis of all of the experimental findings, bearing fuse force capacities have been determined, and appropriate shear stiffness and friction coefficient values for seismic response have been characterized and bracketed.
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Seismic response of Cfs strap-braced stud walls: Experimental investigation

Seismic response of Cfs strap-braced stud walls: Experimental investigation

The development of light weight steel structures in seismic area as Italy requires the upgrading of National Codes. To this end, in the last years a theoretical and experimental study was undertaken at the University of Naples within the Italian research project RELUIS-DPC 2010-2013. The study focused on "all-steel design" solutions and investigated the seismic behaviour of strap-braced stud walls. Three typical wall configurations were defined according to both elastic and dissipative design criteria for three different seismic scenarios. The lateral in-plane inelastic behaviour of these systems was evaluated by twelve tests performed on full-scale Cold-formed strap-braced stud wall specimens with dimensions 2400 x 2700 m subjected to monotonic and reversed cyclic loading protocols. The experimental campaign was completed with seventeen tests on materials, eight shear tests on elementary steel connections and twenty-eight shear tests on strap-framing connection systems. This paper provides the main outcomes of the experimental investigation. Furthermore, the design prescriptions, with particular reference to the behaviour factor and the capacity design rules for these systems, have been proved on the basis of experimental results.
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Ultimate shear performance and friction sliding response of laminated elastomeric bridge bearings

Ultimate shear performance and friction sliding response of laminated elastomeric bridge bearings

However, research on the ultimate failure state and the energy dissipation due to friction sliding is insufficient. Stanton and Roeder [8] suggested that the maximum shear deformation of elastomeric bearings was 75 % in normal design conditions. Schrage [9] studied the sliding property of the elastomeric bearing on the concrete surface. Mori [10] found that the ultimate shear deformation of the elastomeric bearing without being fixed to the two sides could reach 150-225 %. Filipov [11] discussed the effect of the bearing sliding friction on the seismic performance of bridges. Based on the principle of quasi isolation, J. S. Steelman et al. [12, 13] proposed the sliding friction mechanical model of elastomeric bearings during an earthquake and analyzed the effect of the bearing sliding on the seismic performance of bridges. Buckle et al. [14] studied the stability of elastomeric bearings under high shear deformation and analyzed the effect of shear deformation on the vertical critical bearing capacity of the bearing. Li Jianzhong et al. [15, 16] proposed the effective control method of the bridge superstructure displacement and discussed the seismic factors affecting the sliding of the elastomeric bearing. Wang Dongsheng et al. [17, 18] analyzed the effect of the bearing frictional sliding on the seismic response of simple supported girder bridges. Xie Xu et al. [19] studied the effect of bearing failure on the seismic response of the restrainer in bridges. Wang Junjie et al. [20] proposed the restoring mechanism model considering the failure process of bearings and analyzed the effect of the bearing damage on the seismic response of continuous girder bridges.
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Numerical and Experimental Investigation of the Seismic Performance of Steel Concentrically Braced Frame Structures

Numerical and Experimental Investigation of the Seismic Performance of Steel Concentrically Braced Frame Structures

Lifetime performance metrics have been calculated using ten NLTHAs at eight intensity levels. While this combination of analyses and intensity levels was shown to give acceptably accurate performance metrics for a two-storey structure, it is possible that more analyses are required to achieve the same level of accuracy for the taller building frames. Specifically, a more analyses are likely to provide a better prediction of inelastic response under high intensity earthquakes. However, because of the higher weighting of more frequent, less intense events in lifetime performance assessment, the impact on lifetime performance metrics is likely to be minimal. Similarly, collapse fragility functions were developed from a limited-suite analysis method involving only ten ground motion records at a limited number of intensity levels. It is generally accepted in literature that more robust collapse fragility functions can be developed from more comprehensive IDA type analysis using in the order of 40 ground motion records, with more sophisticated methods of selecting analysis intensity levels (Vamvatsikos and Cornell, 2002). Also, as discussed, the definition of collapse can impact the collapse fragility functions calculated. Furthermore, no deteriorating components were employed in the structural model and the lateral stiffness contribution of gravity framing elements is not accounted for in the modelling process, which can lead to conservative predictions of collapse and losses at high intensity levels (Hwang and Lignos, 2017a). However, even with this conservative approach, the impact of collapse on overall lifetime losses was found to be minimal, suggesting that more elaborate structural and seismic response modelling procedures are not necessary for lifetime loss assessment.
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Investigation of Seismic Behavior of V-Shaped Bridge with Memory Alloy Separator in Earthquake Orientation -Affected Joints

Investigation of Seismic Behavior of V-Shaped Bridge with Memory Alloy Separator in Earthquake Orientation -Affected Joints

are a new design approach to reduce the impact of earthquakes on structures. This means that to reduce the seismic demand on the structure, its capacity will be increased, thereby preventing the collapse of the structure and reducing human damages. In this research, a method has been developed that incorporates all the important features of the general design method presented in the Ashto regulations . Numerical investigation of this method demonstrates the considerable satisfaction of the assumptions used in it and confirms the initial design approach of the separated bridges when the elastic column performance is expected [4]. It can also be said for elastomeric separators, the flexibility of elastomeric seismic separator bearings, the main period lengthens the seismically separated buildings and bridges and reduces earthquake forces at the superstructure. Although, this decrease may be associated with large horizontal displacements of the separators, but lateral flexibility plus horizontal displacements results in a significant reduction of the critical buckling load capacity of the elastomeric separators [5 - 9]. Eröz and Disruchiz in 2013 [10] investigated the seismic performance of friction pendulum support (FPS) as representative of sliding separator supports and Lead Rubber Bearing (LRB) as representative of elastomeric supports.
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EXPERIMENTAL INVESTIGATION ON R.C BUILDINGS OF SEISMIC BEHAVIOR UNDER SIGNIFICANCE OF FLUCTUATING FREQUENCY

EXPERIMENTAL INVESTIGATION ON R.C BUILDINGS OF SEISMIC BEHAVIOR UNDER SIGNIFICANCE OF FLUCTUATING FREQUENCY

In linear dynamic analysis, the response of the building to the ground motion is computed in the time domain, and all phase information is thus preserved. Just linear properties are considered. Analytical result of the equation of motion for a one degree of freedom system is normally not conceivable if the external force or ground acceleration changes randomly with time, or if the system is not linear. [35]. Such issues could be handled by numerical time-stepping techniques to integrate differential equations.

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Experimental Evaluation of Seismic Residual Performance for Deteriorated Rubber Bearings in Highway Bridges

Experimental Evaluation of Seismic Residual Performance for Deteriorated Rubber Bearings in Highway Bridges

Thus the performance assessment of deteriorated rubber bearings has emerged as an important research issue. Attention to this problem is also raised by several cases of severe damage to rubber bearings including rubber rupture found after the 2011 Great East Japan Earthquake [2][3]. In the preceding study by the authors, deteriorated elastomeric bearings with natural rubber (ring plate type laminated elastomeric bearings, also known as “ring bearings”) were taken out from an actual bridge site, and a series of shear loading tests were conducted. As the results, quantitative evaluation of the aging deterioration in the reduction of load bearing capacity as well as the change of their stiffness is obtained [4].
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Investigation of the structural response of the groot Olifants River bridge to seismic excitation.

Investigation of the structural response of the groot Olifants River bridge to seismic excitation.

39 5.1 Conclusion The end span from the three spans of the Groot Olifants River bridge located in the Mpumalanga province was modelled and analysed to study the structural behaviour of the bridge when subjected to seismic loads, as well as the feasibility of increasing the applied axle load on the bridge to accommodate the new 44D locomotives in accordance with the requirements set out by the South African freight railway owner. The study revealed that although the Groot Olifants river bridge was not designed for seismic loads, it adheres to the structural requirements as set out in the bridge code and TMH7 clause 3.10.2 for the assessment of bridges using the static method of analysis as discussed in chapter two of this dissertation. The reason for the good structural response when the Groot Olifants river bridge superstructure is subjected to the design response spectrum is not necessarily as a result of good seismic code specifications in the old design code used for the design of this bridge, but rather an indirect effect resulting from the simplicity of the design and the use of large factors of safety as recommended in the old design code. The Groot Olifants river bridge is, however, susceptible to seismic events with a high excitation acceleration such as that of the 0.29 Irpinia earthquake. For the Irpinia earthquake ground motion acceleration (0.29), the Groot Olifants river bridge responds well to the excitation in the Z direction but oscillates excessively due to the excitation in the X and Y directions. This has a large potential of causing the bridge to become unstable, leading to failure. When subject to a high ground acceleration from an earthquake, the maximum tensile strength in some of the critical members are exceeded by as much as 40%. This suggests a high probability of failure. From the transient structural analysis, it is concluded that the Groot Olifants river bridge is not capable of resisting seismic loads from large intensity earthquakes with magnitudes between 6.0 - 6.87 as predicted by Visser & Kijko (2010).
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An Efficient Vertical Seismic Response of a Precast Segmental Bridge Superstructure: A Study

An Efficient Vertical Seismic Response of a Precast Segmental Bridge Superstructure: A Study

Nevertheless, it is able to be inferred that metallic bridge superstructures are liable to damage even for the duration of low-to-moderateshaking, and appear to be greater fragile than structural concretesuperstructures in this regard if not designed well. Typicalharm consists of unseated girders and screw-ups in connections,bearings, pass-frames, and growth joints. In some instances ~appreciably in the course of the Kobe earthquake! Predominant gravity load-sportingparticipants have failed, brought on in a few times by way of the failure ofadditives somewhere else inside the superstructure ~a bearing, as an example!.It may also, therefore, be argued that the recognition loved by using steelbridges is because of the reality that very few steel bridges weresubjected to robust floor movement, and the absence of disintegratingmay be due to a lack of exposure as opposed to the inherent potentialof metallic bridges. Supporting this view is the statement that harm at some stage in low-to-moderate shaking shows a degree of fragility inmetal bridges not visible in structural concrete superstructures. It is crucial to word on this argument that seismic layoutspecs for bridges within the United States do no longer require thespecific design of bridge superstructures ~concrete or metallic! Forearthquake masses. The assumption is made that a superstructurethat is designed for out-of-aircraft gravity hundreds has enoughstrength, by default, to withstand in-plane earthquake loads. This assumption appears to be justified for structural concrete superstructures, that are heavier and stiffer than their steel opposite numbers but can be unfounded for positive styles of steel superstructures,including trusses or slab-and-girder superstructures, both of whichmay be flexible in-aircraft.
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Seismic performance of an unreinforced masonry building: An experimental investigation

Seismic performance of an unreinforced masonry building: An experimental investigation

Before starting the shakings in the longitudinal direction and after each earthquake record excitation in the transverse direction, white-noise tests were conducted to assess the dynamic characteristics of the model building. The white-noise excitation, which consisted of a wide band motion (0.1-30 Hz), was developed using a random function to acquire acceleration records which have approximately the same power spectrum over the frequency range. Tables 2a and 2b present the complete sequence of excitations (including white-noise) and their scaled PGA values for the longitudinal and transverse directions, respectively. It can be seen that except for the El-Centro record in the longitudinal direction, all ground excitations were applied in a sequence of increasing severity (i.e. PGA). Through this loading protocol, the response of URM buildings to different levels of seismic hazard could be inferred, which is in principle similar to the multi-level seismic performance assessment (MSPA) concept [17] except that the rigorous probabilistic earthquake record selection process [18] was not followed.
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An Experimental Investigation on Failure Modes of Piping Components under Excessive Seismic Load

An Experimental Investigation on Failure Modes of Piping Components under Excessive Seismic Load

acceleration (9.0m/s 2 ), but the collapse failure did not occur even in this case. One reason of such result is thought due to a large hysteresis damping under the elastic-plastic region. Figure 4 shows the relation between the maximum input acceleration and the response amplification ratio under the sinusoidal wave input. Here, the response amplification ratio is determined as the ratio of the response acceleration to the input acceleration. The labels in the graph legend, SLE01~SLE05, are the specimens' names. As shown in Fig.4, the amplification ratios were remarkably reduced as the input acceleration level increased. The specimens exceeded the elastic region in these excitations, and it is considered that the large hysteresis damping due to the plastic deformation affected the dynamic response behavior of the specimens. The reversing characteristics of the input motion may also work so as not to cause collapse failure. The experimental results showed that the fatigue failure would be most likely to occur on steel pipes though the reversing dynamic load is up to 20 times larger than the primary stress intensity limitation, and the collapse failure is unlikely to occur.
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EXPERIMENTAL INVESTIGATION INTO THE SEISMIC PERFORMANCE OF HALF- SCALE FULLY PRECAST BRIDGE BENT INCORPORATING EMULATIVE SOLUTION

EXPERIMENTAL INVESTIGATION INTO THE SEISMIC PERFORMANCE OF HALF- SCALE FULLY PRECAST BRIDGE BENT INCORPORATING EMULATIVE SOLUTION

General background on ABC from different nations around the world has been summarized in (Palermo and Mashal, 2012) [1]. Over the past several years, there has been increasing attention given to ABC. A notable example is research into standardized precast substructure systems by (Billington et al., 1999) [2]. There has also been significant interest into ABC by the United States Departments of Transportation including Washington (Khaleghi, 2010) [3], Texas (Ralls et al., 2004) [4], Utah (Burkett et al., 2004) [5] and The Federal Highway Administration (U.S. FHWA, 2011) [6]. However, using precast concrete in regions of high seismicity has been limited mainly due to concerns regarding the performance of connections between the precast components. Lessons from past earthquakes have shown vulnerability of the precast connections in high seismicity (Buckle, 1994) [7]. Therefore, application of ABC in high seismicity requires appropriate solutions proven by experimental testing.
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Characterization of the Cyclic Behavior of Corroded Steel Bridge Bearings and their Influence on Seismic Bridge Performance.

Characterization of the Cyclic Behavior of Corroded Steel Bridge Bearings and their Influence on Seismic Bridge Performance.

Past studies (Kayser 1988, Park 1999, and Czarnecki 2006) have shown that for steel highway bridges, the most prevalent corrosion pattern is general or uniform corrosion. The effect of general corrosion on steel highway bridges is section loss resulting in possible degradation in stiffness, strength, and functionality of a component and change in the friction coefficient between contact materials. Prediction of the rate of corrosion of steel is difficult due to the stochastic nature of corrosion, the lack of quantifiable statistical data, and the effect of local conditions which has led to the use of empirical formulas to predict corrosion rates of steel bridges (Czarnecki and Nowak 2008). Section loss of steel members or components can be accounted for by considering corrosion penetration depth across the steel section. Proposed by Townsend and Zoccola (1982) based on the data from an extensive test program on corrosion of weathering steel, Equation 5-1 characterizes corrosion loss for steel, where C represents the average corrosion penetration (μm) after t years of exposure, A is the corrosion penetration (μm) after one year of exposure, B is a coefficient determined from regression analysis of experimental data, and t is the number of years of exposure. More information regarding this equation and its constants is available in Komp (1987).
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Experimental Investigation on Seismic Retrofitting of RCC Structures

Experimental Investigation on Seismic Retrofitting of RCC Structures

and vulnerable zone of a Reinforced Concrete (RC) moment resisting structure subjected to seismic loads. During an earthquake, the global response of the structure is mainly governed by the behavior of the joints. If the joints behave in a ductile manner, the global behavior generally will be ductile, whereas if the joints behave in a brittle fashion then the structure will display a brittle behavior. The joints of old and non-seismically detailed structures are more vulnerable and behave poorly under the earthquakes compared to the joints of new and seismically detailed structures. Therefore, the joints of such old structures require retrofitting in order to deliver better performance during earthquakes.. This paper reports a experimental investigations carried out for seismic retrofitting of RC beam-column joints using concrete jacketing. The seismic rehabilitation process aims to improve seismic performance and correct the deficiencies by increasing strength, stiffness or deformation capacity and improving connections. The present study focuses on the behavior of reinforced concrete beam-columns strengthened using concrete jacketing subjected to cyclic loading
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Dynamic response of long-span continuous curved box girder bridge under seismic excitation

Dynamic response of long-span continuous curved box girder bridge under seismic excitation

The aforementioned researches have improved dynamic investigation of curved box girder bridges. However, for the dynamic characteristics, most of the concerned researches obtained the self-vibration characteristics of a box girder by energy variation principle and acquired the dynamic characteristics through solving high order differential equations, which consequently leads to a complicated calculation. Furthermore, most of the concerned research objects were straight box girder for simplicity rather than the curved box girder. As for seismic response, the current research efforts lie within the qualitative analysis of the seismic response of curved bridge by finite element method and experimental method, whilst there is a lack of quantitative calculation in the theory. Therefore, this paper attempts to provide a quantitative analysis to fill the theoretical blank in this filed. The element stiffness matrix, mass matrix and earthquake mass matrix of the thin-walled box girder are proposed in present work. The characteristic equations and D’Alembert vibration equation of a curved box girder bridge are deduced by assembling element matrix. Furthermore, eigenvalue function and Newmark-β method are used through MATLAB to solve the characteristic equation and seismic response of box girder bridges. 2. Element matrix
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Parametric Investigation On The Seismic Response Of Voided And Solid Flat Slab Systems

Parametric Investigation On The Seismic Response Of Voided And Solid Flat Slab Systems

Flat slab systems give immense freedom to architects and engineers in the luxury of designing. In a traditional reinforced concrete slab span, the bottom portion will be in tension the top portion will be in compression, and the middle portion will effectively work only as a bridge holding the top and bottom portions together. Since the lateral load resistance of the slab column connection system is small, flat slabs are often designed only for gravity loads, while the seismic force is resisted by shear walls. Even though slabs and columns are not required to share the lateral forces, these deforms with rest of the structure under seismic excitation. The concern is that under such deformations, the slab column system should not lose its vertical load capacity. In order to ensure this, the idea of voided concrete has been investigated since the
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A numerical investigation on the fire response of a steel girder bridge

A numerical investigation on the fire response of a steel girder bridge

Bridges are a critical component of the transportation system whose loss can result in important social and economical consequences (e.g. [1,2]). While a lot of attention has been paid to understanding and predicting the effects on bridges of accidental extreme load events such as earthquakes, winds, scour, and ship collisions (e.g. [3, 4]), fire hazard has got very little consideration as proved by recent literature reviews ([5, 6]). However bridge fires are a major concern for two important reasons. First, traffic on bridges damaged by fire is usually hard to detour and affects the traffic quality in the region. For example, the collapse of two spans of the MacArthur Maze in Oakland, USA on April 29th 2007 due to a fire resulted in repairs and rebuilding operations costing more than US $9 million [7]. In addition, the closure of the Maze was estimated to have a total economic impact to the San Francisco Bay Area of $6 million dollars a day [8]. Secondly, bridge fires are a real threat as shown by data of a voluntary bridge failure survey, which was responded by the departments of transportation of 18 US states [9]. This survey was conducted in 2011 and collected data related to 1746 bridge failures. Although the vast majority of bridges (1001) collapsed for hydraulic reasons (scour, flood) and 520 collapsed due to collision, overload, or deterioration, 54 bridge collapses were due to fire, and only 19 collapses were due to earthquake (seismic states like California participated in the survey).
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Seismic Study of Application of Lead Rubber Bearings in Kutai Kartanegara Steel Arch Bridge

Seismic Study of Application of Lead Rubber Bearings in Kutai Kartanegara Steel Arch Bridge

Abstract— The basic concept of the application of base isolation is by extending the natural period of the structure in order to provide lower seismic acceleration. The paper focuses on the investigation of the application of lead-rubber bearings (LRBs) instead of pot bearings in a new Kutai Kartanegara steel arch bridge located in East Kalimantan province. Even though the bridge is known located in Seismic Zone 1 (the zone with the least seismic risk as per SNI 2833-2013), the study was extended for other higher risk seismic zones, namely Seismic Zones 2, 3, and 4. With the aid of Midas software, the analyses of the bridge structures were carried out and it can be concluded that the higher the seismic risk, the more effective the use of LRBs in dissipating the earthquake energy before transmitting to the bridge superstructure. The reductions of seismic base shears obtained from the analyses were between 23.10 and 44.67 percent and 17.07 and 31.47 percent in the longitudinal and transverse directions, respectively. However, the application of LRBs has a consequence of increasing the horizontal displacements of the bridge, which can be solved by introducing either larger expansion joints or passive dampers. In order to validate the seismic responses, the bridge was analyzed using Time History Analysis (THA) by imposing seven earthquake ground motions, which were scaled to a spectral design of Padang as a requirement by the Indonesian code.
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Seismic Performance of Bridge Bearings Using Shape Memory Alloy  A Review

Seismic Performance of Bridge Bearings Using Shape Memory Alloy A Review

Large proportions of the population in the world lives in seismic hazard regions are at risk from earthquakes of varying severity and frequency of occurrence. Every year earthquakes cause significant loss of life and damage to property. Progress in design and assessment methods of civil structures traditionally followed major earthquakes, whenever the need of improving the safety level of engineering structures became evident. When it was realized in the 1950s and 1960s that structures can survive levels of response accelerations apparently exceeding the ultimate strength level, concept of ductility was formalized and began to be adopted, attributing to the structures the capacity of deforming in elastically without significant strength loss, thus surviving high level earthquakes. It was also understood that a general improvement of the structural response could be obtained by modifying the structural dynamic characteristics and dissipating the seismic energy during the earthquakes.
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Seismic Design of a Prestressed Concrete Bridge

Seismic Design of a Prestressed Concrete Bridge

Today's structural analysis software programs like CSi Bridge can automatically calculate most of the loads that affect any structure. Nonetheless, before modeling, dead and live loads are determined manually beforehand in order to obtain prestressing force and number of strands. In this section, these required preliminary data which is used during modeling will be calculated based on AASHTO LRFD Bridge Design Specifications (AASHTO, 2012) and PCI Bridge Design Manuel, 3 rd Edition.

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