scholarly journals SEISMIC VULNERABILITY OF REINFORCED CONCRETE BRIDGES IN PAKISTAN

2022 ◽  
Vol 28 (2) ◽  
pp. 93-105
Author(s):  
Muhammad Khalid Hafiz ◽  
Qaiser-uz-Zaman Khan ◽  
Sohaib Ahmad
Keyword(s):  
Seismic Hazard ◽  
Seismic Vulnerability ◽  
Seismic Hazard Assessment ◽  
Highway Bridges ◽  
Concrete Bridges ◽  
Seismic Retrofitting ◽  
Seismic Zone ◽  
Code Of Practice ◽  
Recent Earthquakes ◽  
Existing Bridges

Different researchers have performed seismic hazard assessment studies for Pakistan using faults sources which differ from Building Code of Pakistan (BCP 2007) with diverse standard deviations. The results of seismic hazard studies indicate that BCP requires gross revision considering micro and macro level investigations. The recent earthquakes in Pakistan also damaged bridge structures and some studies have been conducted by different researchers to investigate capacity of existing bridges. The most of bridge stock in Pakistan has been designed assuming seismic loads as 2%, 4% and 6% of dead loads following West Pakistan Code of Practice for Highway Bridges. The capacity of eight selected real bridges, two from each seismic zone 2A, 2B, 3 & 4 is checked against BCP demands. Static and dynamic analyses were performed and the piers were checked for elastic limits. It is established that piers are on lower side in capacity and the bridges in zone 2A are generally less vulnerable. Whereas the bridges in zone 2B, 3 and 4 are vulnerable from medium to very high level. Hence, an in-depth analytical vulnerability study of bridge stock particularly in high-risk zone needs to be conducted on priority and appropriate seismic retrofitting schemes need to be proposed.

scholarly journals A hybrid model for mapping simplified seismic response via a GIS-metamodel approach

2014 ◽  
Vol 14 (7) ◽  
pp. 1703-1718 ◽  
Author(s):  
G. Grelle ◽  
L. Bonito ◽  
P. Revellino ◽  
L. Guerriero ◽  
F. M. Guadagno
Keyword(s):  
Seismic Hazard ◽  
Seismic Response ◽  
Hybrid Model ◽  
Computational Models ◽  
Site Response ◽  
Seismic Hazard Assessment ◽  
Physical Parameters ◽  
Seismic Zone ◽  
Acceleration Response ◽  
Good Correspondence

Abstract. In earthquake-prone areas, site seismic response due to lithostratigraphic sequence plays a key role in seismic hazard assessment. A hybrid model, consisting of GIS and metamodel (model of model) procedures, was introduced aimed at estimating the 1-D spatial seismic site response in accordance with spatial variability of sediment parameters. Inputs and outputs are provided and processed by means of an appropriate GIS model, named GIS Cubic Model (GCM). This consists of a block-layered parametric structure aimed at resolving a predicted metamodel by means of pixel to pixel vertical computing. The metamodel, opportunely calibrated, is able to emulate the classic shape of the spectral acceleration response in relation to the main physical parameters that characterize the spectrum itself. Therefore, via the GCM structure and the metamodel, the hybrid model provides maps of normalized acceleration response spectra. The hybrid model was applied and tested on the built-up area of the San Giorgio del Sannio village, located in a high-risk seismic zone of southern Italy. Efficiency tests showed a good correspondence between the spectral values resulting from the proposed approach and the 1-D physical computational models. Supported by lithology and geophysical data and corresponding accurate interpretation regarding modelling, the hybrid model can be an efficient tool in assessing urban planning seismic hazard/risk.

scholarly journals Tectonic styles of expected earthquakes in Italy as an input for seismic hazard modeling

2020 ◽  
Author(s):  
Silvia Pondrelli ◽  
Francesco Visini ◽  
Andrea Rovida ◽  
Vera D'Amico ◽  
Bruno Pace ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Seismic Moment ◽  
Outer Part ◽  
Seismic Hazard Assessment ◽  
Source Model ◽  
Probabilistic Seismic Hazard Assessment ◽  
Seismic Zone ◽  
Moment Tensors ◽  
Area Source ◽  
Tectonic Style

Abstract. Tectonic styles and distributions of nodal planes are an essential input for probabilistic seismic hazard assessment. As a part of a recent elaboration of a new seismic hazard model for Italy, we adopted a cascade criteria approach to parametrize the tectonic style of expected earthquake ruptures and their uncertainty in an area-based seismicity model. Using available or recomputed seismic moment tensors for relevant seismic events (Mw starting from 4.5), first arrival focal mechanisms for less recent earthquakes, and also geological data on past activated faults, we collected a database for the last ~ 100 yrs gathering a thousand of data all over the Italian peninsula and regions around it. The adopted procedure consists, in each seismic zone, of separating the available seismic moment tensors in the three main tectonic styles, making summation within each group, identifying possible nodal plane(s) taking into account the different percentages of tectonic styles and including, where necessary, total or partial random source contributions. Referring to the used area source model, for several seismic zones we obtained robust results, e.g. along the southern Apennines we expect future earthquakes to be mostly extensional, although in the outer part of the chain strike-slip events are possible. In the Northern part of the Apennines we also expect different tectonic styles for different hypocentral depths. In zones characterized by a low seismic moment release, the possible tectonic style of future earthquakes is less clear and it has been represented using different combination (total or partial) of random sources.

scholarly journals A detailed seismic zonation model for shallow earthquakes in the broader Aegean area

2013 ◽  
Vol 1 (6) ◽  
pp. 6719-6784 ◽  
Author(s):  
D. A. Vamvakaris ◽  
C. B. Papazachos ◽  
C. Papaioannou ◽  
E. M. Scordilis ◽  
G. F. Karakaisis
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Active Faults ◽  
Seismic Hazard Assessment ◽  
Maximum Magnitude ◽  
Seismic Zone ◽  
Seismic Zonation ◽  
Aegean Area ◽  
Seismic Zones ◽  
Shallow Earthquakes

Abstract. In the present work we present an effort to define a new seismic zonation model of area type sources for the broader Aegean area, which can be readily used for seismic hazard assessment. The definition of this model is based not only on seismicity information but incorporates all available seismotectonic and neotectonic information available for the study area, in an attempt to define zones which show not only a rather homogeneous seismicity release but also exhibit similar active faulting characteristics. For this reason, all available seismological information such as fault plane solutions and the corresponding kinematic axes have been incorporated in the analysis, as well as information about active tectonics, such as seismic and active faults. Moreover, various morphotectonic features (e.g. relief, coastline) were also considered. Finally, a revised seismic catalogue is employed and earthquake epicentres since historical times (550 BC–2008) are considered, in order to define areas of common seismotectonic characteristics, that could constitute a discrete seismic zone. A new revised model of 113 earthquake seismic zones of shallow earthquakes for the broader Aegean area is finally proposed. Using the proposed zonation model, a detailed study is performed for the catalogue completeness for the recent instrumental period. Using the defined completeness information, seismicity parameters (such as G–R values) for the 113 new seismic zones have been calculated, and their spatial distribution was also examined. The spatial variation of the obtained b values shows an excellent correlation with the geotectonic setting in the area, in good agreement with previous studies. Moreover, a quantitative estimation of seismicity is performed in terms of the mean return period, Tm, of large (M ≥ 6.0) earthquakes, as well as the most frequent maximum magnitude, Mt, for a typical time period (T = 50 yr), revealing significant spatial variations of seismicity levels within the study area. The new proposed seismic zonation model and its parameters can be readily employed for seismic hazard assessment for the broader Aegean area.

scholarly journals Style of faulting of expected earthquakes in Italy as an input for seismic hazard modeling

2020 ◽  
Vol 20 (12) ◽  
pp. 3577-3592
Author(s):  
Silvia Pondrelli ◽  
Francesco Visini ◽  
Andrea Rovida ◽  
Vera D'Amico ◽  
Bruno Pace ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Seismic Moment ◽  
Outer Part ◽  
Seismic Hazard Assessment ◽  
Source Model ◽  
Probabilistic Seismic Hazard Assessment ◽  
Seismic Zone ◽  
Moment Tensors ◽  
Area Source ◽  
Seismic Moment Release

Abstract. The style of faulting and distributions of nodal planes are essential input for probabilistic seismic hazard assessment. As part of a recent elaboration of a new seismic hazard model for Italy, we defined criteria to parameterize the styles of faulting of expected earthquake ruptures and to evaluate their representativeness in an area-based seismicity model. Using available seismic moment tensors for relevant seismic events (Mw≥4.5), first arrival focal mechanisms for less recent earthquakes, and also geological data on past activated faults, we collected a database for the last ∼100 years by gathering a thousand data points for the Italian peninsula and regions around it. In this dataset, we adopted a procedure that consists, in each seismic zone, of separating the available seismic moment tensors into the three main tectonic styles, making a summation within each group, identifying possible nodal plane(s), taking into account the different percentages of styles of faulting, and including where necessary total or partial (even in terms of tectonic style) random source contributions. Referring to the area source model used, for several seismic zones we obtained robust results; e.g., along the central and southern Apennines we expect future earthquakes to be mostly extensional, although in the outer part of the chain reverse and strike-slip events are possible. In the northern part of the Apennines we expect different styles of faulting for different hypocentral depths. In zones characterized by a low seismic moment release, the possible style of faulting of future earthquakes is less clear and it has been represented using different combinations of random sources. The robustness of our results is confirmed when compared with recent relevant earthquakes occurring in Italy.

Seismic Vulnerability Evaluation of Bridges in Memphis and Shelby County, Tennessee

1993 ◽  
Vol 9 (4) ◽  
pp. 803-816 ◽  
Author(s):  
S. Pezeshk ◽  
T. S. Chang ◽  
K. C. Yiak ◽  
H. T. Kung
Keyword(s):  
Seismic Vulnerability ◽  
Seismic Retrofitting ◽  
Screening Procedure ◽  
Seismic Zone ◽  
Structural Elements ◽  
Seismic Evaluation ◽  
Earthquake Preparedness ◽  
Vulnerability Evaluation ◽  
Earthquake Loss ◽  
Shelby County

The focus of this paper is to develop a screening procedure to obtain information and assess vulnerability of bridges located in the New Madrid seismic zone (NMSZ). This screening methodology includes structural elements, site, foundation, and importance of the bridge. An inventory of the river-crossing bridges in Memphis and Shelby County is made using the developed screening procedure; potentially hazardous bridges that require further detailed seismic evaluation and/or immediate seismic retrofitting are identified. The results of this study are important for future maintenance and improvement, earthquake loss estimates, seismic hazard/risk reduction, and earthquake preparedness/rescue plans for river-crossing bridges in the NMSZ.

Probabilistic Seismic Hazard Assessment of Sudan and Its Vicinity

2001 ◽  
Vol 17 (3) ◽  
pp. 399-415 ◽  
Author(s):  
Jamal A. Abdalla ◽  
Yahia E-A. Mohamedzein ◽  
A. Abdel Wahab
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Activity ◽  
Probabilistic Approach ◽  
Seismic Hazard Assessment ◽  
Seismic Source ◽  
Probabilistic Seismic Hazard Assessment ◽  
Seismic Zone ◽  
Ground Acceleration ◽  
Grid Points

This paper presents seismic hazard assessment and seismic zoning of Sudan and its vicinity based on probabilistic approach. The area studied lies between 22° E- 45° E and 0° - 24° N. Tectonics of Sudan and its vicinity is first reviewed. An updated NOAA catalogue, containing both historical and instrumental events and covering the period from 700 A.D. to 1993 is then used. Seismic source regions are modeled and relationships between earthquake magnitude and earthquake frequency are established. A modified attenuation relation is used. Seismic hazard assessment is then carried out for 60 km interval grid points. Seismic hazard maps of the studied area based on peak ground acceleration (PGA) for 10% probability of exceedance for time-spans of 50, 100, 200 and 250 years are presented. The results showed that the PGA ranges from 0.02g for low seismic activity regions to around 0.62g for high seismic activity regions. A seismic zone map is also shown for 475 years return period.

scholarly journals Influence of using Micropiles as Retrofitting Method for Bridge Shallow Footing: Numerical Study

2021 ◽  
Vol 10 (4) ◽  
pp. 186-190
Author(s):  
Hassan. A. Abas ◽  
M.A. Ismaeil
Keyword(s):  
Seismic Hazard ◽  
Significant Influence ◽  
Numerical Study ◽  
Deformation Characteristic ◽  
Seismic Loading ◽  
Seismic Retrofitting ◽  
Before And After ◽  
Existing Bridges ◽  
Plaxis 3D ◽  
Shallow Footing

Seismic retrofitting of the existing bridges, which was not properly constructed for seismic loading, is necessary. This paper examines and evaluates the effect of using micropiles as retrofitting method to improve seismic performance for bridge shallow footing. Numerical simulations using Plaxis-3D have been performed to study the effect of using micropiles to mitigate the seismic hazard and enhance the deformation characteristic of bridge shallow footing. Displacement and acceleration induced by seismic loading before and after retrofitting were assessed and compared. The results showed a significant influence of the micropiles on the control of the displacement and acceleration during the seismic period

scholarly journals Seismisitas di Wilayah Jawa Tengah dan Sekitarnya Berdasarkan Hasil Relokasi Hiposenter dari Empat Jaringan Seismik Menggunakan Model Kecepatan 3-D

EKSPLORIUM ◽  
2020 ◽  
Vol 41 (1) ◽  
pp. 61
Author(s):  
Mohamad Ramdhan ◽  
Priyobudi Priyobudi ◽  
Said Kristyawan ◽  
Andry Syaly Sembiring
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Velocity Model ◽  
Columnar Structure ◽  
Seismic Zone ◽  
Earthquake Parameters ◽  
Central Java ◽  
Hypocenter Relocation ◽  
Tectonic Study

ABSTRAK Relokasi hiposenter merupakan suatu metode yang digunakan untuk mendapatkan parameter-parameter gempa yang presisi. Parameter-parameter tersebut digunakan untuk studi tektonik lanjut seperti seismic hazard assessment pada suatu area. Penggunan model kecepatan 3-D secara teori akan memberikan hasil yang lebih baik dibandingkan dengan model 1-D karena model kecepatan di bawah permukaan bumi lebih mendekati model 3-D. Sebanyak 767 event gempa yang direkam oleh jaringan seismik DOMERAPI, MERAMEX, BMKG, dan BPPTKG digunakan pada penelitian ini. Gempa-gempa tersebut direlokasi dengan model kecepatan 3-D dan dianalisis untuk studi seismotektonik di wilayah Jawa Tengah dan sekitarnya. Hasil relokasi hiposenter menggunakan model kecepatan 3-D berhasil mendeteksi sejumlah fitur tektonik secara lebih jelas seperti struktur kolom yang berkaitan dengan Struktur backthrust di selatan Kebumen. Penampang vertikal arah barat-timur yang melewati Sesar Opak mengindikasikan arah dip bidang sesarnya ke arah timur. Zona seismik ganda yang terdeteksi pada studi sebelumnya tidak bisa teridentifikasi dengan baik pada studi ini. Sejumlah gempa volcano-tectonic (VT) berkaitan dengan aktivitas magma dangkal Gunung Merapi terdeteksi juga dengan jelas pada studi ini.ABSTRACT Hypocenter relocation is a method used to get precise earthquake parameters. They will be useful for an advanced tectonic study like seismic hazard assessment in an area. The hypocenter relocation using a 3-D velocity model will theoretically obtain better results than a 1-D velocity model because the earth subsurface model is closed with a 3-D model. Some 767 earthquakes recorded by DOMERAPI, MERAMEX, BMKG, and BPPTKG networks used in this research. They were relocated by using a 3-D velocity model and analyzed for seismotectonic study in Central Java area and its surroundings. The result of hypocenter relocation using a 3-D velocity model is successfully detecting some tectonic features more clearly like columnar structure related to the backthrust structure at the south of Kebumen. The west-east vertical cross-section crossing the Opak fault indicates the dip of the fault plane is directing to the east. This study could not identify the double seismic zone, which was detected by the previous research. Some volcano-tectonic (VT) earthquakes related to the shallow magma activity of Mount Merapi also are detected clearly in this study.

scholarly journals Impact of Plastic Hinge Properties on Capacity Curve of Reinforced Concrete Bridges

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Nasim Shatarat ◽  
Mutasem Shehadeh ◽  
Mohammad Naser
Keyword(s):  
Plastic Hinge ◽  
Pushover Analysis ◽  
Highway Bridges ◽  
Concrete Bridges ◽  
Nonlinear Behaviour ◽  
Nonlinear Properties ◽  
Capacity Curves ◽  
Finite Element Software ◽  
Existing Bridges ◽  
Hinge Model

Pushover analysis is becoming recently the most practical tool for nonlinear analysis of regular and irregular highway bridges. The nonlinear behaviour of structural elements in this type of analysis can be modeled through automated-hinge or user-defined hinge models. The nonlinear properties of the user-defined hinge model for existing highway bridges can be determined in accordance with the recommendations of the Seismic Retrofit Manual by the Federal Highway Administration (FHWA-SRM). Finite element software such as the software SAP2000 offers a simpler and easier approach to determine the nonlinear hinge properties through the automated-hinge model which are determined automatically from the member material and cross section properties. However, the uncertainties in using the automated-hinge model in place of user-defined hinge model have never been addressed, especially for existing and widened bridges. In response to this need, pushover analysis was carried out for four old highway bridges, of which two were widened using the same superstructure but with more attention to seismic detailing requirements. The results of the analyses showed noticeable differences in the capacity curves obtained utilizing the user-defined and automated-hinge models. The study recommends that bridge design manuals clearly ask bridge designers to evaluate the deformation capacities of existing bridges and widened bridges using user-defined hinge model that is determined in accordance with the provisions of the FHWA-SRM.

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