Transfer of tensile forces from reinforcing steel into the surrounding concrete affects the behavior of reinforced concrete members. This transfer relies on the bond action between the steel and the concrete. Under monotonic loading the part of bond strength due to chemical adhesion is easily exhausted and bearing against the lugs is the primary load-transfer mechanism at loads near the ultimate. These stresses cause internal cracking of concrete at the steel-concrete interface. This paper deals with the finite element modeling of the bond-slip and its application due to internal cracking of the first layer of concrete surrounding the bar and the bending and/ or cracking of the small concrete teeth near the bar lugs. A previously proposed constitutive steel stress-bond slip relation by Mirza and Houde (1979) was used in finite element analysis of reinforced concrete shear wall specimens and the results were presented.

The road authorities aim roads that are resistant, with less maintenance, with high traffic security, with long life and economic. It is difficult to have an economic pavement construction on the subgrade with weak bearing capacity. In this study the effect of the cement stabilization on the weak subgrade and pavement costs has been studied. For this purpose the California Bearing Ratio (CBR) of a weak subgrade that has been stabilized with 4% - 16% cement have been determined. The effect of the increase in the CBR on the pavement costs has been determined thanks to MATLAB program by considering thousands of alternatives. Consequently, the optimum cement content between the decrease on the pavement costs with increase on subgrade’ CBR value and the additional costs spent to increase the CBR value has been determined.

In this study, the effect of expanded polystyrene (EPS) buffers on lateral stresses and deflections of model retaining walls with various flexibility values were investigated. For this purpose, 0.7 m high model walls were instrumented and 1-g model tests were performed in laboratory environment. In the first group of tests, the wall models retain only granular cohesionless backfill whereas in the second and third group of tests, EPS deformable buffers of two different thicknesses were installed between the wall and granular backfill. Tests were repeated for four different wall thicknesses and results were discussed comparatively. As wall flexibility increases, there is a decrease in the load reduction pattern of the buffer. On the other hand, utilization of geofoam buffers with flexible cantilever walls still provides substantial decrease in wall thrust and deflections thus leading to more economical retaining structure design. The lateral earth pressure coefficients determined through model tests were compared to those calculated from Coulomb’s theory for active lateral earth stresses. A graph is provided for the estimation of lateral earth pressure coefficients for various combinations of wall flexibilities and buffer characteristics.

In this paper, the natural frequencies of the axial-loaded Timoshenko multiple-step beam carrying multiple elastic-supported rigid bars are calculated. At first, the coefficient matrices for the elastic-supported rigid bars, the step change in cross-section, left-end support and right-end support of the multiple-step beam are derived. Next, the numerical assembly technique is used to establish the overall coefficient matrix for the whole vibrating system. Finally, equating the overall coefficient matrix to zero one determines the natural frequencies of the system. The natural frequencies of the beams by using secant method for the different values of axial force are presented in tables.

In this research some aggregate samples obtaining from Göller region was examined to investigate the usability of limestone as highway materials. For this reason, three quarries including Gümüþgün quarry at the north part of Isparta, Çine at the south part of Burdur and Daðbeli at the north part of Antalya city are visited and the relevant samples are collected. Sieve test, lose density test, specific gravity and water absorption test, freezethaw test, micro-Deval test and aggregate impact value test conducted on the collected samples in the laboratory. Further, Proktor compaction and CBR test applied on the mixtures accrued with dense graded aggregates. As a result of study, it is concluded aggregate samples collected from there different quarries having reliable physical and mechanical properties to be used as highway base and sub-base material. However, aggregate extracted from Daðbeli quarry would be better to use in the mild climate regions instead of cold and severe weather regions. On the other hand, Gümüþgün aggregate that is abrasion resistant and strength properties indicates higher values than others so it may also be used as a hot mix asphalt aggregate.

In this study, effect of changing of the shear wall ratio to interstorey drift in multistory reinforced concrete buildings with flat slab with continuous drop panel depending on the local site classes is investigated. For that purpose, an R/C frame structure and three shear wall frame structures with different shear wall ratio which have 7 and 9 stories are designed. These structures are analyzed according to response spectrum analysis in Turkish earthquake code for four local site classes. According to the analysis results, interstorey drifts are determined and are compared with boundary values in the earthquake code. According to obtained results, it is seen that, values of interstory drifts lie below limit values for 7 storey models which have 1 % shear wall and 9 storey models which have 1.5 % shear wall. In analysis SAP 2000 structural analysis program is used.

In this study, modeling with time series analysis was done method by using date of monthly road traffic accidents (RTAs) occurred between1977-2006. According to results of analysis and date in period of this study, it was determined that ARIMA(4,1,4) was the best model. In the study monthly accident number are forecasted by appropriate model for 2006: 1-2007: 12 periods. Regression curve is drawn by using the estimated and actual number of RTAs and the correlation coefficient (r = 0.9163) were determined. A strong positive relationship was determined between estimated values and actual values. In addition, the success measure of ARIMA(4,1,4) model was identified by calculating value of root mean square errors (RMSE). It was determined that occur up to a traffic accident in December, October and November, at least a traffic accident in February, March and April