The development of reliable earthquake mitigation plans and seismic risk management procedures can only be based on the establishment of comprehensive earthquake hazard and loss
scenarios. Two cities, Grevena (Greece) and Duzce (Turkey), were used as case studies in order to apply a comprehensive methodology for the vulnerability and loss assessment of lifelines. The methodology has the following distinctive phases: detailed inventory, identification of the typology of each component and system, evaluation of the probabilistic seismic hazard, geotechnical zonation, ground response analysis and estimation of the spatial distribution of seismic motion for different seismic scenarios, vulnerability analysis of the exposed elements at risk. Estimating adequate earthquake scenarios for different mean return periods, and selecting appropriate vulnerability functions, expected damages of the water and waste water systems in Duzce and of the roadway network and waste water system of Grevena are estimated and discussed; comparisons with observed earthquake damages are also made in the case of Duzce, proving the reliability and the efficiency of the proposed methodology. The results of the present study constitute a sound basis for the development of efficient loss scenarios for lifelines and infrastructure
facilities in seismic prone areas. The first part of this paper, concerning the estimation of the seismic ground motions, has been utilized in the companion paper by Kappos et al. (2010) in the same journal.
site effects; seismic scenarios; microzonation; lifelines; infrastructures; vulnerability; Grevena; Duzce
Kyriazis D. Pitilakis, Anastasios I. Anastasiadis, Kalliopi G. Kakderi, Maria V. Manakou, Dimitra K. Manou, Maria N. Alexoudi, Stavroula D. Fotopoulou, Sotiris A. Argyroudis and Kostas G. Senetakis: Aristotle University, Department of Civil Engineering, Research Unit of Geotechnical Earthquake Engineering and Soil Dynamics, 54124, Thessaloniki, Greece
This paper investigates the applicability of newly developed Cu-Al-Mn shape memory alloy (SMA) bars to retrofitting of historical masonry constructions by performing quasi-static tests of half-scale brick walls subjected to cyclic out-of-plane flexure. Problems associated with conventional steel reinforcing bars lie in pinching, or degradation of stiffness and strength under cyclic loading, and in their inability to restrain residual deformations in structures during and after intense earthquakes. This paper attempts to resolve the problems by applying newly developed Cu-Al-Mn SMA bars, characterized by
large recovery strain, low material cost, and high machinability, as partial replacements for steel bars.
Three types of brick wall specimens, unreinforced, steel reinforced, and SMA reinforced specimens are prepared. The specimens are subjected to quasi-static cyclic loading up to rotation angle enough to cause yielding of reinforcing bars. Corresponding nonlinear finite element models are developed to simulate the experimental observations. It was found from the experimental and numerical results that both the steel reinforced and SMA reinforced specimens showed substantial increment in strength and ductility as
compared to the unreinforced specimen. The steel reinforced specimen showed pinching and significant residual elongation in reinforcing bars while the SMA reinforced specimen did not. Both the experimental and numerical observations demonstrate the superiority of Cu-Al-Mn SMA bars to conventional steel reinforcing bars in retrofitting historical masonry constructions.
unreinforced masonry; superelasticity; Cu-Al-Mn shape memory alloy; steel reinforcement; out-of-plane flexure; finite element modeling.
Kshitij C. Shrestha and Yoshikazu Araki: Dept. of Architecture and Architectural Engineering, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo, Kyoto 615-8540, Japan
Takuya Nagae: E-Defense, National Research Institute for Earth Science and Disaster Prevention, Shinjimicho, Miki, Hyogo 673-0515, Japan
Toshihiro Omori, Yuji Sutou, Ryosuke Kainuma and Kiyohito Ishida: Dept. of Materials Science, Graduate School of Engineering, Tohoku University, Aoba-yama 6-6-02, Sendai 980-8579, Japan
An evaluation is presented of the response of a 3-storey R/C structure during the destructive Lefkada earthquake of 14/08/2003. Key aspects of the event include: (1) the unusually strong levels of ground motion (PGA = 0.48 g, SAmax = 2.2 g) recorded approximately 10 km from fault, in downtown Lefkada; (2) the surprisingly low structural damage in the area; (3) the very soft soil conditions (Vs,max = 150 m/s). Structural, geotechnical and seismological aspects of the earthquake are discussed. The study focuses on a 3-storey building, an elongated structure of rectangular plan supported on strip footings, that suffered severe column damage in the longitudinal direction, yet minor damage in the transverse one.
Detailed spectral and time-history analyses highlight the interplay of soil, foundation and superstructure in
modifying seismic demand in the two orthogonal directions of the building. It is shown that soil-structure
interaction may affect inelastic seismic response and alter the dynamic behavior even for relatively flexible systems such as the structure at hand.
This paper develops a probabilistic methodology for the seismic reliability analysis of structures with random properties. The earthquake loading is assumed to be described in terms of response spectra. The proposed methodology takes advantage of the response spectra and thus does not require explicit dynamic analysis of the actual structure. Uncertainties in the structural properties (e.g. member cross-sections, modulus of elasticity, member strengths, mass and damping) as well as in the seismic load (due to uncertainty associated with the earthquake load specification) are considered. The structural reliability is estimated by determining the failure probability or the reliability index associated
with a performance function that defines safe and unsafe domains. The structural failure is estimated using a performance function that evaluates whether the maximum displacement has been exceeded. Numerical illustrations of reliability analysis of elastic and elastic-plastic single-story frame structures are presented first. The extension of the proposed method to elastic multi-degree-of-freedom uncertain structures is also studied and a solved example is provided.
structural reliability; uncertainty; random damping; Monte Carlo Simulation; FORM; earthquake loads; response spectrum.
Abbas Moustafa: Department of Civil Engineering, Minia University, Minia 61111, Egypt
Sankaran Mahadevan: Department of Civil & Environmental Engineering, Vanderbilt University, Nashville, TN 37235, USA
The seismic design of a two-storey precast reinforced-concrete building structure equipped with viscous dampers is presented in this paper with twofold purpose. The first goal is to verify the applicability of a practical procedure for the identification of the mechanical characteristics of the viscous dampers which allow to achieve target performance levels, originally proposed by the authors for moment-resisting building frames, also with reference to