Ambient vibration based seismic evaluation of isolated Gülburnu highway bridge

This paper describes ambient vibration based seismic evaluation procedure of an isolated highway bridge. The procedure includes finite element modeling, ambient vibration testing, finite element model updating and time history analysis. Gülburnu Highway Bridge located on the Giresun–Espiye state highway is selected as a case study. Three dimensional finite element model of the bridge is created by SAP2000 software to determine the dynamic characteristics analytically. Since input force is not measured, Operational Modal Analysis is applied to identify dynamic characteristics. Enhanced Frequency Domain Decomposition and Stochastic Subspace Identification methods are used to obtain experimental dynamic characteristics. Analytical and experimental dynamic characteristic are compared with each other and finite element model of the bridge is updated by changing of material properties to reduce the differences between the results. Analytical model of the bridge after model updating is analyzed using 1992 Erzincan earthquake record to determine the seismic behavior. EW, NS and UP components of the ground motion are applied to the bridge at the longitudinal, transverse and vertical directions, respectively. It is demonstrated that the ambient vibration measurements are enough to identify the most significant modes of highway bridges. Maximum differences between the natural frequencies are reduced averagely from 9% to 2% by model updating. It is seen from the earthquake analyses that friction pendulum isolators are very effective in reducing the displacements and internal forces.     

Widespread overspill from a saline density‐current channel and its interaction with topography on the south‐west Black Sea shelf

Seaward of the Bosphorus Strait, the south‐west Black Sea shelf is dominated by the world's largest channel network maintained by a quasi‐continuous saline (ca 35 → 31 psu) underflow. Calculations indicate that >85% of the initial discharge of ca 10⁴ m³s^?1 spills overbank before the shelf edge. This paper documents interaction of the overspill with sea bed topography using multibeam bathymetry, echo‐sounder images of the water column, conductivity–temperature–depth profiles and sediment cores. Overbank spill is widespread, particularly through crevasse channels and on the middle shelf where confinement by channel banks is negligible. Towards the outer shelf, the wind‐driven Rim Current advects mud along the shelf, contributing to levée successions and deposition on stoss sides of elongate transverse ridges. Echo‐sounder profiles reveal metre‐scale eddies over megaflutes, and breaking lee waves and internal hydraulic jumps over ridges. Megaflutes reach 600 m long and 7 m deep, yet form where the underflow, outside the flute, is no thicker than ca 2 to 5 m. Two types of elongate seaward‐facing ridges are recognized. Type 1 ridges, 2 to 5 m high, consist of bivalve‐rich muddy sand in low‐angle (3·5° to 6°) cross‐sets created by the underflow. Type 2 ridges, ca 5 m high, have crests up to 2 km long and a buried wedge‐shaped foundation (the ‘ridge‐core’) comprised of facies similar to Type 1 ridges. These ridge‐cores are blanketed on the landward side by stratified muds, and are capped by obliquely oriented ribs supporting a diverse benthic community. This facies distribution is interpreted to result from stoss‐side and lee‐side velocity and turbulence fluctuations induced by internal hydraulic jumps and breaking lee waves in overspilling portions of the underflow. Experimental results published by W.H. Snyder and co‐workers effectively explain ridge evolution and flow across the ridges, and therefore can be applied with confidence to less easily studied deep‐marine settings swept by turbidity currents.     

Monitoring deformations on engineering structures in Kozlu Hard Coal Basin

Underground coal mining activities in Kozlu Hard Coal Basin have reached a level affecting ground layers inside the mining seams and the surface just above the mining operations, causing movements in vicinity of the basin. The movements emerge as collapsing in vertical direction and as sliding, curling and bending in horizontal direction and are termed mining subsidence since they exhibit themselves in ground layers and on earth surfaces in mining environments. These mining-induced movements cause damages and destructions on structures inside and on the surface of mining grounds, and the dimensions of these damages depend upon quality of structures and magnitude of movements. In order to contribute toward a solution to these problems and to mitigate the effects arising during and after mining activities, one should identify and investigate damage prone movements and determine the movement–time relationship. Therefore, it is immensely important to observe, investigate, and measure these movements in regions where mining activities take place. This study focuses on the surface movement-related deformations on the engineering structures in the basin such as Kozlu Seaport and some part of the Zonguldak-Kozlu Road. For this reason, subsidence monitoring points were established on the engineering structures in the basin in a geodetic network concept, and three periods of precise leveling and static GPS observations were conducted. Analyzing these two types of geodetic observations, active and residual subsidence effects were determined for both Kozlu Seaport and the Road nearby.     

Structural damages of the May 19, 2011, Kütahya–Simav earthquake in Turkey

Reconnaissance observations are presented on the building damage caused by the May 19, 2011, Kütahya–Simav earthquake in Western Turkey as well as an overview of strong ground motion data recorded during the earthquake is given. According to Disaster and Emergency Management Presidency of Turkey, the magnitude of the earthquake is 5.7 in local magnitude scale. Although the earthquake can be regarded as a moderate event when considering its magnitude and strong motion recordings, it caused excessive structural damage to buildings in Simav district and several villages in the near vicinity. During the field investigation, different types of structural damage were observed mainly in the reinforced concrete frame buildings with infill walls and masonry buildings with various types of construction materials. Observed damage resulted from several deficiencies in structural and non-structural components of the buildings. Poor construction materials and workmanship, non-conforming earthquake-resistant design and construction techniques and non-ductile detailing are the main reasons for such an extensive damage, as observed in many past earthquakes in Turkey.     

Interpretation of gravity anomalies to delineate some structural features of Biga and Gelibolu peninsulas,and their surroundings (north-west Turkey)

On the basis of gravity data, derived anomaly traces were presented for the interpretation of some shallow structural features of Biga and Gelibolu peninsulas. Since building general understanding of subtle details about subsurface geology is of great importance considering that the study area is tectonically important, some advanced data processing techniques were implemented to gravity anomalies in a detailed manner. The procedures were performed using a MATLAB-based software package (Gravity and Magnetic Interpretation – GMINTERP). First, a finite element method was utilised to produce the residual data-set which is expected to reflect short wavelength anomalies arising from shallower geological structures, and thereafter some derivative-based algorithms were executed to analyse the residual data. The general anomaly patterns obtained from the applications clearly corresponded to the well-known surface geology map of the study area. Derivative-based anomaly maps put forward some findings about the existence of an old caldera structure in the western part of the Biga Peninsula. Additionally, abrupt lateral changes in anomaly amplitudes indicated the presence of some major structural discontinuities. Thus, findings yielded to make significant geological interpretations that might be important for further investigations. This study also showed that GMINTERP software package proved useful in assisting geological interpretation using geophysical potential field data-sets.     

Relatedness between contemporary and subfossil cladoceran assemblages in Turkish lakes

Cladocerans are valuable indicators of environmental change in lakes. Their fossils provide information on past changes in lake environments. However, few studies have quantitatively examined the relationships between contemporary and sub-fossil cladoceran assemblages and no investigations are available from Mediterranean lakes where salinity, eutrophication and top-down control of large-bodied cladocerans are known to be important. Here we compared contemporary Cladocera assemblages, sampled in summer, from both littoral and pelagic zones, with their sub-fossil remains from surface sediment samples from 40 Turkish, mainly shallow, lakes. A total of 20 and 27 taxa were recorded in the contemporary and surface sediment samples, respectively. Procrustes rotation was applied to both the principal components analysis (PCA) and redundancy analysis (RDA) ordinations in order to explore the relationship between the cladoceran community and the environmental variables. Procrustes rotation analysis based on PCA showed a significant accord between both littoral and combined pelagic–littoral contemporary and sedimentary assemblages. RDA ordinations indicated that a similar proportion of variance was explained by environmental variation for the contemporary and fossil Cladocera data. Total phosphorus and salinity were significant explanatory variables for the contemporary assemblage, whereas salinity emerged as the only significant variable for the sedimentary assemblage. The residuals from the Procrustes rotation identified a number of lakes with a high degree of dissimilarity between modern and sub-fossil assemblages. Analysis showed that high salinity, deep water and high macrophyte abundance were linked to a lower accord between contemporary and sedimentary assemblages. This low accord was, generally the result of poor representation of some salinity tolerant, pelagic and macrophyte-associated taxa in the contemporary samples. This study provides further confirmation that there is a robust relationship between samples of modern cladoceran assemblages and their sedimentary remains. Thus, sub-fossil cladoceran assemblages from sediment cores can be used with confidence to track long-term changes in this environmentally sensitive group and in Mediterranean lakes, subjected to large inter-annual variation in water level, salinity and nutrients.     

Response Surface Modeling of Cu(II) Removal from Electroplating Waste by Adsorption: Application of Box–Behnken Experimental Design

The use of kaolinite‐based clay minerals as a low‐cost natural adsorbent for the removal of Cu(II) from electroplating waste leachate was studied. Batch experiments were conducted to determine the effects of varying adsorbent loading, initial pH, adsorbent dosage, and contact time. Box–Behnken design with three variables like initial pH, adsorbent dosage, and contact time at three different levels was studied to identify a significant correlation between the effects of these variables to the amount of Cu(II) adsorbed. The methodology identifies the principal experimental variables, which have the greatest effect on the adsorption process. After optimizing the input variables by using Simplex algorithm, the adsorption of Cu(II) was maximal (99.9% with a maximum (positive) standard deviation of 9.4) at pH 6.24, adsorbent dosage of 0.83 g L^?1, and contact time of 97 min, respectively. Furthermore, the experimental values are in good agreement with predicted values, the correlation coefficient and adjusted correlation coefficients were found to be 0.96 and 0.87, respectively.     

Treatability of Dye Solutions Containing Disperse Dyes by Fenton and Fenton‐Solar Light Oxidation Processes

This study attempts to explore the possibility of treating dye solutions containing Disperse Yellow 119 and Disperse Red 167 by Fenton and Fenton under solar‐light oxidation processes. Experiments were conducted to examine the effects of various operating conditions on the performance of the treatment systems. The Fenton results showed that 98.6% spectral absorption coefficient (SAC) and 90.8% chemical oxygen demand (COD) removals were proved at pH 3, 50 mg/L Fe²⁺, and 75 mg/L H₂O₂, 15 min oxidation time for Disperse Yellow 119. After 40 min solar irradiation time during Fenton process the SAC removal was 99.1%. COD reduction of about 98.3% was observed at the same time. It was also obtained as 97.8% SAC and 97.7% COD removal with pH 3, 75 mg/L Fe²⁺, 100 mg/L H₂O₂, and 25 min oxidation time for Disperse Red 167 at this optimum conditions. For Disperse Red 167 during Fenton under solar light process, after 40 min of solar irradiation time the SAC and COD reduction were obtained 99.3 and 98.4%, respectively.     

Physical parameters of some close binaries: ET Boo,V1123 Tau,V1191 Cyg,V1073 Cyg and V357 Peg

With the aim of providing new and up-to-date absolute parameters of some close binary systems, new BVR CCD photometry was carried out at the Ankara University Observatory (AUG) for five eclipsing binaries, ET Boo, V1123 Tau, V1191 Cyg, V1073 Cyg and V357 Peg between April, 2007 and October, 2008. In this paper, we present the orbital solutions for these systems obtained by simultaneous light and radial velocity curve analyses. Extensive orbital solution and absolute parameters for ET Boo system were given for the first time through this study. According to the analyses, ET Boo is a detached binary while the parameters of four remaining systems are consistent with the nature of contact binaries. The evolutionary status of the components of these systems are also discussed by referring to their absolute parameters found in this study.