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SEISMIC EVALUATION OF PADMA MULTIPURPOSE BRIDGE PIER USING RESPONSE SPECTRUM ANALYSIS
Abstract
The Padma Multipurpose Bridge (PMB) is a dream infrastructure to connect the southwest to northern and eastern regions of Bangladesh. It is considered one of the most challenging engineering projects in the world in terms of concept, design, management, and construction. In this study, a 3D Finite Element (FE) model of the actual PMB has been developed using a commercial computer package. Since the bridge is composed of seven repetitive (6x150m) 900mm modules made of composite steel warren truss, the FE model is idealized for a single module six-span continuous straight module. The superstructure of the bridge is separated from the substructure by the Friction Pendulum Bearing (FPB). Accounting loads from all possible sources, HL-93 vehicular live load is considered for the upper deck and Dedicated Freight Corridor (DFC) loadings are assumed for the railway where wagon loads are combined from different locomotives. To achieve accurate soil-structure interaction, p-y soil spring following API guideline was adopted to conform flexible support system. The bridge's displacement responses have been evaluated for the 475, 975, and 2475-year return periods for Service Level, Design Basis, and the Maximum Credible Earthquake (MCE), respectively.
... Evaluating Performance-based damage states of the pier using a displacement-based design approach may illustrate the accurate pier responses and hence potential repair and retrofitting Ahmed, 2020, Ahmed et al., 2021) strategy after the seismic event . Recently, a study on the seismic evaluation of the Padma Multi-purpose bridge pier shows that the seismic demand of the bridge pier is only 36% of its capacity for an earthquake return period of 2475 yrs (Ahmed & Moniruzzaman, 2022). However, the dynamic response of the padma bridge pier or bridge superstructures due to the seismic event or moving train has not been investigated yet. ...
... Evaluating Performance-based damage states of the pier using a displacement-based design approach may illustrate the accurate pier responses and hence potential repair and retrofitting (Mahmud and , Ahmed et al., 2021 strategy after the seismic event (Farzana and Ahmed, 2022). Recently, a study on the seismic evaluation of the Padma Multi-purpose bridge pier shows that the seismic demand of the bridge pier is only 36% of its capacity for an earthquake return period of 2475 yrs (Ahmed & Moniruzzaman, 2022). However, the dynamic response of the padma bridge pier or bridge superstructures due to the seismic event or moving train has not been investigated yet. ...
Padma Multipurpose Bridge (PMB) is one of the most important projects in the history of Bangladesh due to its regional importance, economic benefit, and primary connectivity of one-third population of the country. The bridge is 6.15km long, connecting the ends of Mawa and Janjira in Bangladesh. The entire project is challenging to construct and complex in design as it contains both four-lane highways and train tracks supported by a double-deck composite warren truss. In this study, the dynamic response of the truss due to the moving train has been analyzed using the Moving Element Method (MEM). In this process, a separate finite element model has been developed using Finite Element (FE) program to convert the double deck truss into an equivalent beam. Analysis has been conducted for a series of different load cases, converging to the most realistic case where the actual train parameters are considered. Parametric studies have been carried out to determine the dynamic responses of the bridge with varying pier spacing and speed of the train. The most optimal solution has been discussed with the effect of the vibration of the train acting on the multipurpose Padma bridge. The bridge's dynamic amplification factor (DAF) at a design speed of below 100km/hr is found 1.05. The parametric study shows that the critical train speed for the PMB is 1400km/hr resulting in the bridge resonance with a DAF of 18. It is also evident that with the increase of pier spacing the resonance of the bridge is expected to occur at a relatively lower speed.
One of the major aspects of retrofitting or strengthening of existing concrete structures is to install rebars using chemical adhesives. In a view to lighten the disturbance of existing structures by reducing the number of holes, high strength rebars (80 grade; nominal yield strength of 550 MPa) are more preferable for repairing and strengthening structural components. Here, a total of 108 specimens were prepared to evaluate the performance of post-installed high strength deformed rebar (PIHSDR) in concrete using pull-out tests. Test parameters included concrete compressive strength (f'c) rebar diameter, embedment length of rebar into concrete and concrete cover to rebar diameter ratio (c/db) to investigate the bond behaviors of PIHSDR at the epoxy-concrete interface. Bond stress-slip relationships for PIHSDR were obtained, investigated, and hence compared with previous research and available codes. It was observed that most of the specimens showed concrete rapture, splitting, or rebar rapture failure and none of them showed pull-out failure which indicates that the epoxy resins are very much effective as bonding chemicals for retrofitting concrete structures in the steel-concrete interface. Besides, regression analyses were performed using the experimental data to obtain a closed-form equation for predicting the bond strength for PIHSDR. The predicted bond strengths were observed close to the actual test data with a high coefficient of determination (R2 = 0.99) and very low root mean square error (0.078).
The Summary results from a series of field experiments at a test site in Greece are presented, involving an in situ instrumented bridgepier model built on realistic foundation conditions, to study the dynamic behavior of structure-foundation-soil system. It was attempted to link the variation of its dynamic characteristics to certain changes in its structural system, including the development of structural damage. This measured response was next utilized to validate numerical tools capable of predicting influences arising from such structural changes as well as from soil-foundation interaction. This bridge-pier model was supported on soft soil deposits allowing the study of structure-foundation-soil interaction effects during low-to-medium intensity artificial excitations. The in situ experiments provided measurements that were used to verify fundamental analytical solutions for soil-structure interaction. They were also used to validate numerical simulations that were developed to predict the response of the studied structure and thus, back-evaluate modeling assumptions. The obtained accuracy of the numerical predictions must be partly attributed to sound knowledge of the mechanical properties of the pier model and of the soil, not necessarily the case in all practical applications. It is evident that more complex finite-element models can improve the quality of the prediction only in cases where their parameters can be defined equally well. A special study further focused on the radiation of the waves generated by the vibration of the bridge-pier model through the soil medium. It is deemed that this comprehensive experimental investigation of soil-structure interaction provides measurements of the system response and enhances our understanding of the physical phenomenon as a whole. (C) 2014 American Society of Civil Engineers.
Appropriate seismic assessment of reinforced concrete bridges is an important challenge in structural engineering in consideration
of the number and relevance of bridges built without applying advanced codes of practice and of the strategic role of transportation
networks in modern economy. This paper focuses on some relevant aspects of the damage development and collapse modes of hollow
piers, as commonly designed in the past. The following aspects have been considered: absence of confinement, inadequate shear
strength, shifting of the critical section, insufficient length of lap splices. A series of experimental tests has been designed
and performed; the capacity of predicting appropriate results of formulations recommended in codes of practice or proposed
in recent research documents has been checked comparing experimental and analytical results.
Many concrete bridges around the world have passed their service life and are at high risk of collapse, especially in active seismic regions. This is particularly true in many developing and underdeveloped countries, where deficient construction and underpreparedness would result in a major catastrophe should a major seismic event occur. Thus, there lies a need to introduce an efficient, cost-effective, and readily available method of bridge rehabilitation. In this study, steel-reinforced grout (SRG) jacketing is used as a seismic strengthening technique for reinforced concrete bridge piers. Two bridge piers, one seismically damaged and one seismically deficient, were jacketed with SRG and then tested to observe their seismic response. The findings from the experimental program revealed that SRG jacketing can reha-bilitate/repair a damaged bridge pier, and restore its flexural capacity, energy dissipation capacity, and ductility. While strengthening a seismically deficient pier, results showed that the flexural capacity and energy dissipation capacity could be improved, and ductility could be enhanced.
Stainless steel is getting popularity worldwide to build corrosion-resistant and sustainable structures in adverse environmental conditions. The structural deterioration due to corrosion and frequent repairing cost is a major problem to use carbon steel in bridges. Development of structural performance levels and corresponding limit states under seismic hazard are considered to be basic criteria for performance-based seismic design (PBSD). This paper aims to determine performance-based damage states for stainless steel (SS) reinforced concrete bridge pier by performing nonlinear static pushover analysis (NSPA) with incremental lateral loading. Different damage states are developed corresponding to the performance levels such as yielding, cracking, spalling and crushing for SS reinforced concrete bridge pier and compared with that of carbon steel-reinforced concrete bridge pier. Parametric studies have been conducted to investigate the influences of longitudinal reinforcement ratio, yield strength of steel and concrete compressive strength on the structural properties of SS reinforced piers. It is observed from this study that the post-earthquake functionality of SS reinforced bridge pier is improved in terms of ductility, energy absorption capacity compared to that made from conventional carbon steel.
The Gulf of Bohai has a huge area of floating ice in winter each year, and when seawater freezes, significant uncertainties are introduced in the offshore structural design. In this study, a complete bridge analysis model is proposed to investigate the dynamic responses of offshore bridges in the Bohai Sea subjected to stochastic ice loads by floating sea ice. Based on a real stochastic ice load spectrum, a simulation methodology to generate the stochastic ice load process is proposed. The soil resistance is modelled utilising the American Petroleum Institute-based cyclic p-y, t-z, and Q-z springs. A dynamic analysis is conducted in the time domain utilising the finite element method and considering stochastic ice loads. The influences of undrained soil strength and water depth on the dynamic behaviours of the bridge are systematically investigated. The results show that the dynamic responses of bridges in deep water are much larger than those in shallow water, and the soil–structure interaction (SSI) can substantially affect the structural vibrations. The result from the method can also be used to identify the most critical condition for bridge design under ice loads.
The 6⋅15-km-long Padma road and rail bridge will become a landmark structure in Bangladesh and one of the largest river crossings in the world. The design encountered significant engineering challenges, particularly from the hostile site conditions and the merciless forces of nature. During the monsoon season the Padma River becomes fast flowing, and is susceptible to deep scour, demanding deep, piled foundations. The bridge site is also in an area of considerable seismic activity, leading to significant seismic loads being exerted on the structure. In the design, extensive engineering studies were conducted, advanced computational analyses were employed and innovative engineering solutions were developed to ensure that the bridge will be able to survive the challenges of nature in its long design working life. The project has accumulated a significant body of knowledge in seismic-resilient and scour-tolerant design, and it has advanced understanding of bridge behaviour in conditions of severe earthquake and deep riverbed scour.
The present paper proposes equivalent stiffness and energy dissipation properties of reinforced concrete hollow bridge piers
to be used in the context of response spectrum performance based assessment and design. The work is carried out by performing
parametric numerical analysis using a 2D fibre model calibrated against experimental results and by varying the longitudinal
steel reinforcement ratio, height over width ratio, normalised axial force, level of confinement and concrete class of a rectangular
hollow section reinforced with Tempcore B500C steel. The results of the analysis are given in the form of charts and closed
form expressions for the yield curvature and moment, ultimate ductility, post yielding stiffness ratio and energy dissipated
of the section, and are translated to the member level through the plastic hinge length approach. Likewise, the parameters
of a Takeda model derived from the parametric analysis are given for use in nonlinear time history analysis.
KeywordsBridge pier hollow section-Performance based design-Equivalent stiffness-Equivalent damping-Plastic hinge length-Takeda model
Performance based seismic analysis of stainless steel reinforced concrete bridge pier using damping ductility relationship
- K Farzana
- K Ahmed
Farzana, K. & Ahmed, K. (2020). Performance based seismic
analysis of stainless steel reinforced concrete bridge pier
using damping ductility relationship. IABSE-JSCE Joint
Conference on Advances in Bridge Engineering-IV August
26-27, 2020, Dhaka, Bangladesh. 115-122.