Journal of Earthquake Engineering

An important record of ground motion from a M6.4 earthquake occurring on May 1, 2003, at epicentral and fault distances of about 12 and 9 km, respectively, was obtained at a station near the city of Bingöl, Turkey. The maximum peak ground values of 0.55g and 36 cm/s are among the largest ground-motion amplitudes recorded in Turkey. From simulations and comparisons with ground motions from other earthquakes of comparable magnitude, we conclude that the ground motion over a range of frequencies is unusually high. Site response may be responsible for the elevated ground motion, as suggested from analysis of numerous aftershock recordings from the same station. The mainshock motions have some interesting seismological features, including ramps between the P- and S-wave that are probably due to near- and intermediate-field elastic motions and strong polarisation oriented at about 39 degrees to the fault (and therefore not in the fault-normal direction). Simulations of motions from an extended rupture explain these features. The N10E component shows a high-amplitude spectral acceleration at a period of 0.15 seconds resulting in a site specific design spectrum that significantly overestimates the actual strength and displacement demands of the record. The pulse signal in the N10E component affects the inelastic spectral displacement and increases the inelastic displacement demand with respect to elastic demand for very long periods.

Thessaly, Central Greece, like most of the Aegean realm is characterized by a diffuse seismic activity. Both instrumental and historic data are revised and, with few exceptions, this information substantiates that the local seismicity is characterised by a shallow seismogenic depth that can generate important destructions though distributed to limited areas. However, historical sources like diaries and church books or, for more recent events, newspapers are almost completely lacking before the 17th century. On the other hand, recent palaeoseismological surveys carried out along some of the active faults of Eastern Thessaly clearly document the occurrence of past earthquakes during latest Pleistocene and Holocene times. The present research is an attempt of partially filling the gap of our knowledge on the seismicity of the area. At this regard, we followed the methodological approaches of the Historical Seismology and the Archaeoseismology. In particular, we focused our investigations on the interpretation of both direct and indirect evidences issued from Greek inscriptions, monuments and settlements of Ancient and Byzantine times. Special emphasis is given to the recently discovered Great Theatre of Larissa that shows important evidences of seismically induced damages. We analyse all this information with the intention of reconstructing the late Holocene seismic evolution of the northeastern sector of Thessaly, while the final aim of this article is the seismic hazard assessment of this region, whose major urban centre is Larissa that represents the third town of Greece.

Error propagation for the direct and improved implementations of the subfamily of HHT-α method with favourable numerical dissipation is studied herein for a pseudodynamic test. Analytical results show that the direct implementation of the subfamily of HHT-α method is inappropriate for the pseudodynamic testing although it possesses desired numerical dissipation. However, it is found that the error propagation of high frequency responses can be effectively suppressed by numerical dissipation for the improved implementation of this subfamily of integration methods. Furthermore, the error amplification factor for the improved implementation highly depends on the number of remaining time steps to be performed and the spectral radius of the amplification matrix. In fact, a small spectral radius and/or a large number of remaining time steps will lead to a small error amplification factor. This means an error introduced in an early time step will contribute less to the cumulative error at the end of the test as compared to an error introduced in a later time step.

Different aspects of spectral analysis for site response evaluation are investigated in this study. The segmental cross-spectrum is proposed in spectral analysis of earthquake ground motions. The performance of segmental cross-spectrum in contrast with the conventional methods is investigated through the mathematical modelling, numerical analysis and application to earthquake data recorded at Chiba and Shinfuji downhole arrays in Japan. In analysis of earthquake data, the soil amplification function is identified using both uphole/downhole (U/D) and H/V spectral ratios. The advantage of segmental cross-spectrum is assessed by comparing identified amplification functions using different spectral methods and theoretical soil response. The reliability of site response estimations obtained by H/V spectral ratio using segmental cross- and Fourier spectra is also examined by means of cross-validation with the U/D spectral ratio of earthquake motion and theoretical soil response. Furthermore, the application of segmental cross-spectrum in nonlinear soil response is examined by comparing the amplification function of weak and strong motions for both methods. The results validate the advantage of segmental cross-spectrum in both linear and nonlinear soil response, particularly, when it used with H/V technique.

An overview of the Pseudo-dynamic (PsD) testing of a 3D reinforced concrete frame is described. The role of pre-test analysis in leading the test preparation and execution is presented through actual situations such as (i) the necessity and detailed procedure of the pre-test condition assessment, (ii) estimation of actuator force, displacement and rotation demands during the test and (iii) determination of mass (water tanks) magnitude and location to fulfil the test requirements. Comparison of analytical and experimental results is presented in addition to the description of observed damage inflicted on the structure. Finally, the effect of fixed-end rotation due to bond-slip in the reinforced concrete columns on the results obtained is discussed.

A continuous damage model and different simplified numerical strategies are proposed to simulate the behaviour of reinforced concrete (R/C) walls subjected to earthquake ground motions. For 2D modelling of R/C walls controlled primarily by bending, an Euler multilayered beam element is adopted. For 3D problems, a multifibre Timoshenko beam element having higher order interpolation functions has been developed. Finally, for walls with a small slenderness ratio we use the Equivalent Reinforced Concrete model. For each case, comparison with experimental results of R/C walls tested on shaking table or reaction wall shows the advantages but also the limitations of the approach.