Modal analysis and ambient vibration measurements on Mila-Algeria cable stayed bridge

Kibboua, Abderrahmane,Farsi, Mohamed Naboussi,Chatelain, Jean-Luc,Guillier, Bertrand,Bechtoula, Hakim,Mehani, Youcef Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.2

The seismic response analysis of an existing bridge needs a mathematical model that can be calibrated with measured dynamic characteristics. These characteristics are the periods and the associated mode shapes of vibration and the modal damping coefficients. This paper deals with the measurements and the interpretation of the results of ambient vibration tests done on a newly erected cable stayed bridge across the Oued Dib River at Mila city in Algeria. The signal analysis of ambient vibration records will permit to determine the dynamic characteristics of the bridge. On the other hand, a 3-D model of the bridge is developed in order to assess the frequencies and the associated modes of vibration. This information will be necessary in the planning of the test on the site (locations of the sensors, frequencies to be measured and the associated mode shapes of vibration). The frequencies predicted by the finite element model are compared with those measured during full-scale ambient vibration measurements of the bridge. In the same way, the modal damping coefficients obtained by the random decrement method are compared to those of similar bridges.

Analytical fragility curves for typical Algerian reinforced concrete bridge piers

Kibboua, Abderrahmane,Naili, Mounir,Benouar, Djillali,Kehila, Fouad Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.39 No.3

This paper illustrates the results of a seismic vulnerability study aimed to derive the fragility curves for typical Algerian reinforced concrete bridge piers using an analytical approach. Fragility curves express the probability of exceeding a certain damage state for a given ground motion intensity (e.g., PGA). In this respect, a set of 41 worldwide accelerometer records from which, 21 Algerian strong motion records are included, have been used in a non-linear dynamic response analyses to assess the damage indices expressed in terms of the bridge displacement ductility, the ultimate ductility, the cyclic loading factor and the cumulative energy ductility. Combining the damage indices defined for 5 damage rank with the ground motion indices, the fragility curves for the bridge piers were derived assuming a lognormal distribution.

Analytical fragility curves for typical Algerian reinforced concrete bridge piers

Abderrahmane Kibboua,Mounir Naili,Djillali Benouar,Fouad Kehila 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.39 No.3

This paper illustrates the results of a seismic vulnerability study aimed to derive the fragility curves for typical Algerian reinforced concrete bridge piers using an analytical approach. Fragility curves express the probability of exceeding a certain damage state for a given ground motion intensity (e.g.,PGA). In this respect, a set of 41 worldwide accelerometer records from which, 21 Algerian strong motion records are included, have been used in a non-linear dynamic response analyses to assess the damage indices expressed in terms of the bridge displacement ductility, the ultimate ductility, the cyclic loading factor and the cumulative energy ductility. Combining the damage indices defined for 5 damage rank with the ground motion indices, the fragility curves for the bridge piers were derived assuming a lognormal distribution.

Modal analysis and ambient vibration measurements on Mila-Algeria cable stayed bridge

Abderrahmane Kibboua,Mohamed Naboussi Farsi,Jean-Luc Chatelain,Bertrand Guillier,Hakim Bechtoula,Youcef Mehani 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.2

The seismic response analysis of an existing bridge needs a mathematical model that can be calibrated with measured dynamic characteristics. These characteristics are the periods and the associated mode shapes of vibration and the modal damping coefficients. This paper deals with the measurements and the interpretation of the results of ambient vibration tests done on a newly erected cable stayed bridge across the Oued Dib River at Mila city in Algeria. The signal analysis of ambient vibration records will permit to determine the dynamic characteristics of the bridge. On the other hand, a 3-D model of the bridge is developed in order to assess the frequencies and the associated modes of vibration. This information will be necessary in the planning of the test on the site (locations of the sensors, frequencies to be measured and the associated mode shapes of vibration). The frequencies predicted by the finite element model are compared with those measured during full-scale ambient vibration measurements of the bridge. In the same way, the modal damping coefficients obtained by the random decrement method are compared to those of similar bridges.

Seismic assessment of a R/C strategic existing building

Mehani, Youcef,Kibboua, Abderrahmane Techno-Press 2007 Structural Engineering and Mechanics, An Int'l Jou Vol.26 No.6

Algeria is a country with a high seismic activity. During the last decade, many destructive earthquakes occurred, particularly in the northern part, causing enormous losses in human lives, buildings and equipments. In order to reduce this risk in the capital and avoid serious damages to the strategic existing buildings, the government decided to invest into seismic upgrade, strengthening and retrofitting of these buildings. In doing so, seismic vulnerability study of this category of buildings has been considered. Structural analysis is performed on the basis of site investigation (inspection of the building, collecting data, materials, general conditions of the building, etc), and existing drawings (architectural plans, structural design, etc). The aim of these seismic vulnerability studies is to develop guidelines and a methodology for rehabilitation of existing buildings. This paper will provide insight to the vulnerability assessment and strengthening of the telecommunication centre, according to the new code RPA 99/version 2003. Both, static equivalent method and non linear dynamic analysis are performed in this study.

Assessment of seismic fragility curves for existing RC buildings in Algiers after the 2003 Boumerdes earthquake

Mehani, Youcef,Bechtoula, Hakim,Kibboua, Abderrahmane,Naili, Mounir Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.46 No.6

The main purpose of this paper is to develop seismic fragility curves for existing reinforced concrete, RC, buildings based on the post earthquake field survey and the seismic performance using capacity design. Existing RC buildings constitute approximately 65% of the total stock in Algiers. This type of buildings, RC, was widely used in the past and chosen as the structural type for the future construction program of more than 2 millions apartments all over Algeria. These buildings, suffered moderate to extensive damage after the 2003 Boumerdes earthquake, on May 21st. The determination of analytical seismic fragility curves for low-rise and mid-rise existing RC buildings was carried out based on the consistent and complete post earthquake survey after that event. The information on the damaged existing RC buildings was investigated and evaluated by experts. Thirty four (34) communes (districts) of fifty seven (57), the most populated and affected by earthquake damage were considered in this study. Utilizing the field observed damage data and the Japanese Seismic Index Methodology, based on the capacity design method. Seismic fragility curves were developed for those buildings with a large number data in order to get a statistically significant sample size. According to the construction period and the code design, four types of existing RC buildings were considered. Buildings designed with pre-code (very poor structural behavior before 1955), Buildings designed with low code (poor structural behavior, between 1955-1981), buildings designed with medium code (moderate structural behavior, between 1981-1999) and buildings designed with high code (good structural behavior, after 1999).

Damage Quantification of Steel Moment Resisting Frames using Ductility Parameters

Youcef Mehani,Hakim Bechtoula,Abderrahmane Kibboua,Mounir Naili 대한토목학회 2013 KSCE Journal of Civil Engineering Vol.17 No.6

The aim of a well designed construction in a seismic area is to avoid the collapse of buildings during major earthquakes. Up to now, this damage is expressed by the absence of plastic collapse, which takes into account the notion of the cinematic ductility in terms of demand and capacity. The ductility capacity must satisfy a certain level imposed by codes, without considering the duration of the strong motion and thus, number of plastic incursions and the fatigue phenomenon effects in the dissipative zones of the structure. Analytical investigation was carried out for six steel moment resisting frames with different dynamic parameters, subjected to six earthquakes with various characteristics. In total, thirty six cases were studied with a non linear dynamic analysis to assess the factors that affect the damage distribution of structures. Hereafter, the main results of this analysis are presented.

Assessment of seismic fragility curves for existing RC buildings in Algiers after the 2003 Boumerdes earthquake

Youcef Mehani,Hakim Bechtoula,Abderrahmane Kibboua,Mounir Naili 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.46 No.6

The main purpose of this paper is to develop seismic fragility curves for existing reinforced concrete, RC, buildings based on the post earthquake field survey and the seismic performance using capacity design. Existing RC buildings constitute approximately 65% of the total stock in Algiers. This type of buildings, RC, was widely used in the past and chosen as the structural type for the future construction program of more than 2 millions apartments all over Algeria. These buildings, suffered moderate to extensive damage after the 2003 Boumerdes earthquake, on May 21st. The determination of analytical seismic fragility curves for low-rise and mid-rise existing RC buildings was carried out based on the consistent and complete post earthquake survey after that event. The information on the damaged existing RC buildings was investigated and evaluated by experts. Thirty four (34) communes (districts) of fifty seven (57), the most populated and affected by earthquake damage were considered in this study. Utilizing the field observed damage data and the Japanese Seismic Index Methodology, based on the capacity design method. Seismic fragility curves were developed for those buildings with a large number data in order to get a statistically significant sample size. According to the construction period and the code design, four types of existing RC buildings were considered. Buildings designed with pre-code (very poor structural behavior before 1955), Buildings designed with low code (poor structural behavior, between 1955-1981), buildings designed with medium code (moderate structural behavior, between 1981-1999) and buildings designed with high code (good structural behavior, after 1999).