Numerical Modeling of RC Bridges for Seismic Risk Analysis

2016 ◽  
pp. 457-481
Author(s):  
Pedro Silva Delgado ◽  
António Arêde ◽  
Nelson Vila Pouca ◽  
Aníbal Costa
Keyword(s):  
Seismic Response ◽  
Seismic Vulnerability ◽  
Seismic Analysis ◽  
Plastic Hinge ◽  
Probabilistic Approach ◽  
Damage Model ◽  
Experimental Tests ◽  
Concrete Bridges ◽  
Seismic Risk Analysis ◽  
Hinge Model

The main purpose of this chapter is to present numerical methodologies with different complexities in order to simulate the seismic response of bridges and then use the results for the safety assessment with one probabilistic approach. The numerical simulations are carried out using three different methodologies: (i) plastic hinge model, (ii) fiber model and (iii) damage model. Seismic response of bridges is based on a simplified plane model, with easy practical application and involving reduced calculation efforts while maintaining adequate accuracy. The evaluation of seismic vulnerability is carried out through the failure probability quantification involving a non-linear transformation of the seismic action in its structural effects. The applicability of the proposed methodologies is then illustrated in the seismic analysis of two reinforced concrete bridges, involving a series of experimental tests and numerical analysis, providing an excellent set of results for comparison and global calibration.

Basic Seismic Response Capability of Hospitals in Lima, Peru

2018 ◽  
Vol 13 (02) ◽  
pp. 138-143 ◽  
Author(s):  
Nicola Liguori ◽  
Nicola Tarque ◽  
Celso Bambaren ◽  
Sandra Santa-Cruz ◽  
Juan Palomino ◽  
...  
Keyword(s):  
Seismic Response ◽  
Seismic Event ◽  
Seismic Vulnerability ◽  
Operational Performance ◽  
Seismic Risk Analysis ◽  
Existing Structures ◽  
Operational Level ◽  
Low Performance ◽  
Essential Resource ◽  
Response Capability

AbstractObjectiveThe objective of the study was to research the basic seismic response capability (BSRC) of hospitals in Lima Metropolitana. A large number of wounded could be registered in case of an earthquake; therefore, operational hospitals are necessary to cure the injured. The study focused on the operational performance of the hospitals, autonomies of essential resources such as power, water, medical gases, and medicine, in addition to the availability of emergency communication system and ambulances.MethodsData by a probabilistic seismic risk analysis have been used to assess the operational level of the hospitals. Subsequently, availability of an essential resource has been combined with the immediately operational hospitals to evaluate the BSRC of the health facilities.ResultsForty-one of Lima’s hospitals have been analyzed for a seismic event with 72-100 years of a return period. Three hospitals (7.3%) were capable to work in a self-sufficient manner for 72 hours, another three (7.3%) for 24 hours, and one (2.4%) for 12 hours.ConclusionResults showed a low performance of the hospitals in case of an earthquake. The issue is due to the high seismic vulnerability of the existing structures. Given the importance of Lima city in Peru, structural and nonstructural retrofitting plans should be implemented to improve the preparedness of the health system in case of an emergency. (Disaster Med Public Health Preparedness. 2019;13:138–143)

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.

scholarly journals Multi-Stripe Seismic Assessment of Precast Industrial Buildings With Cladding Panels

2021 ◽  
Vol 7 ◽  
Author(s):  
Krunal Gajera ◽  
Bruno Dal Lago ◽  
Luca Capacci ◽  
Fabio Biondini
Keyword(s):  
Seismic Response ◽  
Seismic Vulnerability ◽  
Probabilistic Approach ◽  
Frame Structure ◽  
Industrial Building ◽  
Lumped Mass ◽  
Limit States ◽  
Empirical Observation ◽  
Industrial Buildings ◽  
Cladding Panels

Following the empirical observation of widespread collapses of cladding panel connections of precast industrial buildings under recent seismic events, new design solutions have been developed in the framework of the European project SAFECLADDING, including isostatic systems effectively decoupling the seismic response of frame structure and cladding panels. The present paper is aimed at evaluating the seismic response and vulnerability of precast frame structures employing pendulum, cantilever, and rocking cladding connection systems. Within the framework of the research project RINTC–Implicit seismic risk of code-conforming structures funded by the Italian Civil Protection Department within the ReLUIS program, the seismic performance of a typical precast industrial building has been assessed with a probabilistic approach based on the results of static and multi-stripe dynamic non-linear analyses. The seismic vulnerability assessment of each structural system has been carried out with reference to life safety and damage limit states considering three sites of increasing seismic hazard in Italy. The effect of distributed panel mass modeling vs. more common lumped mass modeling has been analyzed and critically commented based on the results of demand over capacity (D/C) ratios. Moreover, biaxial seismic D/C ratios have been evaluated for realistic strong hinge connections for cladding panels.

SEISMIC VULNERABILITY ASSESSMENT FOR SAN FRANCISCO TEMPLE IN MORELIA, MEXICO

2019 ◽  
Vol 3 (Special Issue on First SACEE'19) ◽  
pp. 207-2016
Author(s):  
Guillermo Martinez ◽  
David Castillo ◽  
José Jara ◽  
Bertha Olmos
Keyword(s):  
San Francisco ◽  
Seismic Vulnerability ◽  
Seismic Analysis ◽  
Three Dimensional ◽  
Middle Part ◽  
Seismic Demands ◽  
Modeling And Analysis ◽  
Seismic Records ◽  
Cracking Pattern ◽  
The Temple

This paper presents a first approximation of the seismic vulnerability of a sixteenth century building which is part of the historical center of Morelia, Mexico. The city was declared World Heritage by United Nations Educational, Scientific and Cultural Organization in 1991. The modeling and analysis of the building was carried out using a three-dimensional elastic tetrahedral finite elements model which was subjected to probabilistic seismic demands with recurrences of 500 yrs and 1000 yrs in addition to real seismic records. The model was able to correctly identify cracking pattern in different parts of the temple due to gravitational forces. High seismic vulnerability of the arched window and the walls of the middle part of the bell tower of the temple was indicated by the seismic analysis of the model.

Behavior of Structures Using Simple Plastic Hinge Theory

1994 ◽  
Author(s):  
Ramakrishnan Maruthayappan ◽  
Hamid M. Lankarani
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Cantilever Beam ◽  
Reliable Method ◽  
Plastic Hinge ◽  
Element Model ◽  
Finite Element Models ◽  
Computational Program ◽  
Hinge Model ◽  
The Impact

Abstract The behavior of structures under the impact or crash situations demands an efficient modeling of the system for its behavior to be predicted close to practical situations. The various formulations that are possible to model such systems are spring mass models, finite element models and plastic hinge models. Of these three techniques, the plastic hinge theory offers a more accurate model compared to the spring mass formulation and is much simpler than the finite element models. Therefore, it is desired to model the structure using plastic hinges and to use a computational program to predict the behavior of structures. In this paper, the behavior of some simple structures, ranging from an elementary cantilever beam to a torque box are predicted. It is also shown that the plastic hinge theory is a reliable method by comparing the results obtained from a plastic hinge model of an aviation seat structure with that obtained from a finite element model.

Numerical Investigation of Ductile Fracture in Pipelines Under Complex Loading Using a Phenomenological Damage Model

2021 ◽  
Author(s):  
Iago S. Santos ◽  
Diego F. B. Sarzosa
Keyword(s):  
Ductile Fracture ◽  
Mechanical Response ◽  
Numerical Study ◽  
Damage Model ◽  
Stress Triaxiality ◽  
Numerical Procedure ◽  
Complex Loading ◽  
Experimental Tests ◽  
Compact Tension ◽  
Axial Tensile

Abstract This paper presents a numerical study on pipes ductile fracture mechanical response using a phenomenological computational damage model. The damage is controlled by an initiation criterion dependent on the stress triaxiality and the Lode angle parameter, and a post-initiation damage law to eliminate each finite element from the mesh. Experimental tests were carried out to calibrate the elastoplastic response, damage parameters and validate the FEM models. The tested geometries were round bars having smooth and notched cross-section, flat notched specimens under axial tensile loads, and fracture toughness tests in deeply cracked bending specimens SE(B) and compact tension samples C(T). The calibrated numerical procedure was applied to execute a parametric study in pipes with circumferential surface cracks subjected to tensile and internal pressure loads simultaneously. The effects of the variation of geometric parameters and the load applications on the pipes strain capacity were investigated. The influence of longitudinal misalignment between adjacent pipes was also investigated.

Seismic Vulnerability of Existing RC Buildings and Influence of the Decoupling of the Effective Masonry Panels from the Structural Frames

2012 ◽  
Vol 268-270 ◽  
pp. 646-655
Author(s):  
Fabio de Angelis ◽  
Donato Cancellara
Keyword(s):  
Reinforced Concrete ◽  
Seismic Vulnerability ◽  
Seismic Analysis ◽  
Effective Interaction ◽  
Collapse Mechanism ◽  
Limit States ◽  
Capacity Curves ◽  
Masonry Infills ◽  
N2 Method ◽  
Structural Frame

In the present work we discuss on the seismic vulnerability of reinforced concrete existing buildings. In particular we consider a reinforced concrete building originally designed for only gravitational loads and located in a zone recently defined at seismic risk. According to the Italian seismic code NTC 2008 a displacement based approach is adopted and the N2-method is considered for the nonlinear seismic analysis. In the analysis all the masonry infill panels in effective interaction with the structural frame are considered for the nonlinear modeling of the structure. The influence of the effective masonry infills on the seismic response of the structure is analyzed and it is discussed how the effect of the masonry infills irregularly located within the building can give rise to a worsening of the seismic performance of the structure. It is shown that in the present case a not uniform positioning of the masonry infills within the building can give rise to a fragile structural behavior in the collapse mechanism. Furthermore a comparative analysis is performed by considering both the structure with the effective masonry infills and the bare structural frame. For these two structures a pushover analysis is performed, the relative capacity curves are derived and it is shown that fragile collapse mechanisms can occur depending on the irregular positioning of the effective masonry infills. Accordingly it is discussed how in the present case a decoupling of the effective masonry infills from the structural frame can give rise to a smoother response of the capacity curves. For the examined case of an obsolete building with irregular positioning of the masonry panels, the choice of decoupling the effective masonry panels from the structural frame may facilitate the retrofitting strategies for the achievement of the proper safety factors at the examined limit states.

Lateral Behavior of Precast Segmental UHPC Bridge Columns Based on the Equivalent Plastic-Hinge Model

2019 ◽  
Vol 24 (3) ◽  
pp. 04018124 ◽  
Author(s):  
Zhen Wang ◽  
Jingquan Wang ◽  
Yuchuan Tang ◽  
Yufeng Gao ◽  
Jian Zhang
Keyword(s):  
Plastic Hinge ◽  
Bridge Columns ◽  
Hinge Model ◽  
Lateral Behavior

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.

Characterisation of Fracture and HAC Resistance of an Individual Microstructural Constituent with Micro-Cantilever Testing

2016 ◽  
Vol 713 ◽  
pp. 66-69
Author(s):  
Walter Costin ◽  
Olivier Lavigne ◽  
Andrei G. Kotousov
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Plastic Hinge ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Ferrous Alloys ◽  
Microstructural Constituent ◽  
Macro Scale ◽  
Micro Cantilever ◽  
Hinge Model

This paper focuses on the application of miniaturized fracture tests to evaluate the fracture and hydrogen assisted cracking (HAC) resistance of a selected microstructural constituent (acicular ferrite, AF) which only occurs in microscopic material volumes. Site-specific Focused Ion Beam (FIB) micro-machining was used to fabricate sharply notched micro-cantilevers into a region fully constituting of AF. The micro-cantilevers were subsequently tested under uncharged and hydrogen charged conditions with a nanoindenter. The load displacement curves were recorded and analysed with a simplified plastic hinge model for the uncharged specimen, as AF demonstrated an essentially ductile behaviour. The simplified model assisted with FE simulations provided values of the critical plastic crack tip opening displacement (CTOD). A value of the conditional fracture toughness was thereby determined as 12.1 MPa m1/2. With LEFM, a threshold stress intensity factor, Kth, to initiate hydrogen crack propagation in AF was found to range between 1.56 MPa m1/2 and 4.36 MPa m1/2. All these values were significantly below the corresponding values reported for various ferrous alloys in standard macro-tests. This finding indicates that the fracture and HAC resistance at the micro-scale could be very different than at the macro-scale as not all fracture toughening mechanisms may be activated at this scale level.

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