SIMULATION TECHNIQUES FOR COLLAPSE ANALYSIS OF RC BRIDGE UNDER STRONG EARTHQUAKE
Author: Li-min Sun , Xing-peng Yu and Cen Zhou | Size: 640 KB | Format:PDF | Quality:Unspecified | Publisher: 4th International Conference on Earthquake Engineering Taipei, Taiwan October 12-13, 2006 | Year: 2006 | pages: 13
Collapse analysis is becoming increasingly significant as the performance-based design is being gradually adopted in the seismic design of bridges. To deal with the strong nonlinearity and large deformation of the structure, dynamic simulation methods were introduced in this paper. Some
simulation techniques were used to realize the fracture of structural member; and the contact and impact of broken reinforced concrete member with each other were also taken into consideration in the methods. The simulation of the whole collapse process of Cypress Double-deck Viaduct in 1989 Loma Prieta was performed with the above method. The analysis results agree well with the damage observed in site and this indicated that the simulation method and techniques proposed is capable to be utilized for collapse analysis of RC bridges. With simulation results of collapse analysis, failure modes and potential collapse mechanism of RC bridge under strong earthquake can be illustrated. A new double-deck viaduct with Y type pier was built in Shanghai recently. Its upper deck is urban arterial highway and the lower deck is urban light railway system. With the proposed simulation techniques, the response of this viaduct under earthquake was analyzed and the simulation results were verified by a pseudo-dynamic test with this bridge. With the analysis result, the seismic vulnerability of the double-deck viaduct was assessed and suggestion was proposed to improve the seismic
performance of bridge. Many high pier RC bridges are been constructed crossing deep valleys at mountain areas in the western China, where the geotechnical condition is more complicated and the earthquake is more active. To
verify the seismic response performance and to predict the damage mechanism of a high pier bridge under strong earthquake, a high pier RC at a typical mountain area was investigated as an example. The bridge is a multi-span continuous frame structure with high piers. Its deck consists of two parallel separate girders with curve. In this simulation, first, detail nonlinear analysis for bridge elements those
might be heavily damaged during earthquake were analyzed using advanced elasto-plastic constitutive model. Then, based on that, a simplified constitutive model were established for the collapse analysis of the whole bridge. The methodology and results of the simulation in this paper are expected to be helpful for the seismic design and analysis of RC bridge.
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NONLINEAR SEISMIC ANALYSIS OF QUASI-ISOLATION SYSTEMS FOR EARTHQUAKE PROTECTION OF BRIDGES
Author: EVGUENI T. FILIPOV | Size: 7.8 MB | Format:PDF | Quality:Unspecified | Publisher: University of Illinois at Urbana-Champaign, 2012 | Year: 2012 | pages: 275
Quasi-isolation is a modern bridge seismic design philosophy where nonlinearity is permitted to occur in specific bearing components such that forces transferred into the
substructure are reduced and isolation is achieved by sliding of the bearings. The system is a pragmatic approach for providing earthquake resilient bridges in locations such as the eastern
and central United States, as well as in many locations around the world where there is significant earthquake risk at long recurrence periods. Such a seismic risk does not typically
justify the design of a rigorous classical isolation system, but instead, a low-complexity, low-cost quasi-isolation approach could provide significant mitigation of earthquake effects. The proposed system employs a set of fixed bearings at one intermediate substructure, and all other substructures are instrumented with isolation bearings that permit thermal expansion such as elastomeric bearings with an elastomer-concrete sliding interface or elastomeric bearings with a PTFE (Teflon) to stainless steel sliding interface. L-shaped steel side retainers are placed in the transverse direction of the elastomeric bearings, and along with the low-profile fixed bearings, these components prevent bridge movement during service oading, but break-off and permit sliding at high earthquake loads.
NONLINEAR SEISMIC ANALYSIS OF QUASI-ISOLATION SYSTEMS FOR EARTHQUAKE PROTECTION OF BRIDGES
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Performance Based Earthquake Engineer ing: Application to an Actual Bridge-Foundation-Ground System
Author: Joel P. Conteb , Yuyi Zhang | Size: 1 MB | Format:PDF | Quality:Unspecified | Publisher: 12th Italian National Conference on Earthquake Engineering, Pisa, Italy, June 10-14, 2007 | Year: 2007 | pages: 18
Performance-based earthquake engineering (PBEE) is emerging as the next-generation design and evaluation
framework under which new and existing structures will be analyzed for seismic adequacy. This paper presents
the application of the PBEE methodology developed at the Pacific Earthquake Engineering Research
(PEER) Center to the Humboldt Bay Middle Channel (HBMC) Bridge modeled and analyzed as a nonlinear
soil-foundation-structure interaction (SFSI) system. The HBMCB, with precast and prestressed concrete Igirders
and cast-in-place concrete slabs, is fairly representative of older AASHTO-Caltrans girder bridges. It
is supported on pile groups in soils potentially vulnerable to liquefaction during an earthquake, which could
induce lateral spreading and permanent soil deformations.
This paper presents the nonlinear finite element model of the bridge-foundation-ground (BFG) system used in
this study and then focuses on the several analytical steps of the PEER PBEE methodology as applied to this
bridge. This methodology integrates in a probabilistic framework seismic hazard analysis, seismic demand
analysis, capacity analysis, reliability/damage analysis, and loss analysis. Several potential failure mechanisms
of the HBMC Bridge are considered: flexural failure of bridge piers, failure of shear key(s), and unseating.
For each failure mechanism, several limit/damage-states measuring the stage of formation of the mechanism
are defined. The seismic reliability against these limit-states is evaluated in terms of mean annual
rate/frequency of exceedance or, alternatively, return period. As outcome of seismic loss analysis, the seismic
loss hazard curve expresses the mean annual frequency of exceeding any total annual seismic repair/
replacement cost. The paper presents selective results illustrating the various steps of the PEER PBEE
methodology as applied to the HBMC Bridge
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This paper presents seismic analysis of a three-span deck girder bridge. A finite element model to analyze the deck girder bridge has been developed by using finite element software called ANSYS. The entire work has been carried out in two steps. In the first step, a three dimensional model of the bridge has been subjected to equivalent static earthquake loading by following AASHTO guideline. In the second step, Response
Spectrum analysis has been performed. Then the design forces and moments at the column bases of the bridge are obtained by using the above two methods. Finally a comparative study of the design values has been performed between those two methods mentioned above. From the entire study it has been found that the magnitude of the axial forces are almost same in those two methods but the design moments and shear forces
vary significantly. In case of design moment, the result found from response spectrum method (RSM) is about
1.74 times of the design value obtained by equivalent static force method (ESFM). Therefore it can be said that there is a possibility of achieving under design of the bridge if follows the ESFM. Based on overall findings, it can be suggested that the response spectrum method should be performed for seismic load analysis of the bridge to achieve a safer design.
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The collapse of the Showa Bridge during the 1964 Niigata earthquake features in many publications as an iconic example of the detrimental effects of liquefaction. It was generally believed that lateral spreading was the cause of failure of the bridge. This hypothesis is based on the reliable eye witness that the bridge failed 1 to 2 minutes after the earthquake started which clearly ruled out the possibility that inertia (during the initial strong shaking) was the contributor to the collapse. Bhattacharya (2003), Bhattacharya and Bolton (2004), Bhattacharya et al (2005) reanalyzed the bridge and showed that the lateral spreading hypothesis cannot explain the failure of the bridge. The aim of this short paper is to collate the research carried out on this subject and reach conclusions based on analytical studies and quantitative analysis.
It is being recognised that precise quantitative analysis can be difficult due to lack of instrumented data. However, as
engineers, we need to carry out order-of-magnitude calculations to discard various failure hypotheses.
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THE EARTHQUAKE RESPONSE OF BRIDGE PILE FOUNDATIONS TO LIQUEFACTION INDUCED LATERAL SPREAD DISPLACEMENT DEMA NDS
Author: Sharid Khan Amiri | Size: 23.4 MB | Format:PDF | Quality:Unspecified | Publisher: UNIVERSITY OF SOUTHERN CALIFORNIA | Year: 2008 | pages: 417
The earthquake response of various types of pile foundations supporting a variety of bridge structures to liquefaction induced lateral spread displacement demands is analyzed using the concepts of pile ductility and pile pinning. The soil/pile model uses the stress-strain response of reinforced concrete and ste
el, incorporating both the axial and lateral loads for structural elements, and p-y curvesto represent interface elements to assess the pile response during earthquake
induced lateral spread displacement demands.
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Damage of Bridges in 2008 Wenchuan, China, Earthquake
Author: Kazuhiko KAWASHIMA , Yoshikazu TAKAHASHI , Hanbin GE , Zhishen WU and Jiandong ZHANG | Size: 2 MB | Format:PDF | Quality:Unspecified | Publisher: Reconnaissance Report on Damage of Bridges in 2008 Wenchuan, China, Earthquake, Journal of Earthquake Engineering, Vol. 13, pp.956-998, 2009. | Year: 2009 | pages: 20
This is a reconnaissance report on the damage to bridges during the 2008 Wenchuan, China, earthquake.
Site investigation was conducted by the authors on August 10-14, 2008. Presented is a detailed discussion of
the damage to twelve bridges as well as possible damage mechanisms. Characteristics of two near-field
ground accelerations and Chinese seismic bridge design practices are also presented. An investigation of the
damage finds insufficient intensity of seismic design force, inadequate structural detailing for enhancing the
ductility capacity and an absence of unseating prevention devices.
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Lessons Learned from Seismic Collapse Assessment of Buildings for Evaluation of Bridge Structures
Author: Abbie B. Liel and Curt B. Haselton | Size: 219 KB | Format:PDF | Quality:Unspecified | pages: 12
Due to recent advancements in performance-based earthquake engineering methods, in modeling of complex nonlinear structural behavior, and in characterization of earthquake ground motions, it is becoming possible to directly simulate earthquakeinduced structural collapse. These simulations can be used to develop probabilistic descriptions of structures’ seismic collapse risk. This paper first summarizes recent
developments in assessment of seismic collapse risks for building structures, which apply nonlinear time-history analyses to predict when structural collapse occurs. In the second part, the discussion focuses on how the lessons learned from these building collapse risk assessments can be applied to predicting the seismic collapse risk of bridge structures. The paper proposes extending current assessments of bridge
seismic performance (which typically focus on prediction of structural damage prior to collapse) to include robust assessments seismic collapse safety. Key issues for
structural collapse assessment relate to ground motion scaling and spectral shape, creation of nonlinear structural simulation models (differing in certain critical characteristics from models used to predict pre-collapse response), and incorporating
uncertainties in ground motions and structural modeling.
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Behavior&Analysis and Design of Steel work Elements
Author: Dr.Sayed Bahaa Machaly- Prof. of steel structure - Faculty of Engineering | Size: 21.02 MB | Format:PDF | Quality:Scanner | Year: 2008 | pages: 762 | ISBN: 9772335498
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EARTHQUAKE TIP Learning Earthquake Design and Construction
Author: C. V. R. MURTY | Size: 16 MB | Format:PDF | Quality:Unspecified | Publisher: National Information Center of Earthquake Engineering Indian Institute of Technology Kanpur Kanpur 208016 | pages: 55
The Republic Day earthquake of 26 January 2001 in Gujarat clearly demonstrated the earthquake vulnerability profile of our country. It created a considerable interest amongst the professionals
associated with construction activities in any form, as well as the non-professionals regarding the earthquake safety issues. While the subject of earthquake engineering has its own sophistication and a lot of new research is being conducted in this very important subject, it is also important to widely disseminate the basic concepts of earthquake resistant constructions through simple language. With this objective, the Indian Institute of Technology Kanpur (IITK) and the Building Materials and Technology Promotion Council (BMTPC), a constituent of the Ministry of Urban Development & Poverty Alleviation, Government of India, launched the IITK-BMTPC Series on Earthquake Tips in early 2002. Professor C. V. R. Murty was requested to take up the daunting task of expressing difficult concepts in very simple language, which he has very ably done.
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