In this study, experimental and numerical investigations were conducted to examine the time-dependent creep and earthquake performance of the historical Plaka stone bridge, which was constructed in 1866 in Arta, Greece. During the original construction of the bridge in 1866, Khorasan mortar with an egg white additive was used between the stone elements. Furthermore, when the bridge underwent restoration in 2015, Khorasan mortar with an eggshell additive was employed between the stone elements. Consequently, two distinct 3D finite-difference models were developed for this study. In the first bridge model, egg white was used in the Khorasan mortar, replacing water at various proportions of 0%, 25%, 50%, 75%, and 100%. In contrast, for the second model, eggshell was incorporated into the Khorasan mixture at percentages of 25%, 50%, 75%, and 100%, relative to the lime amount. Subsequently, the mortars were subjected to curing periods of 1 day, 7 days, and 28 days, and their mechanical properties were determined through unconfined compression strength experiments. Taking into account the determined strengths of the mortars, the kn and ks stiffness values of the interface elements between the stone elements and Khorasan mortar were calculated. In the 3D model, each stone element was individually represented, resulting in a total of 1,849,274 stone elements being utilized. Non-reflecting boundary conditions were applied to the edge boundaries of the bridge model, and the Burger creep and Mohr–Coulomb material models was employed for time-dependent creep and seismic analyses, respectively. Subsequently, time-dependent creep analyses were conducted on the bridge, and seismic events that occurred in the region where the bridge was located were simulated to assess their impact. Based on the results of the time-dependent creep and seismic analyses, we observed that the use of 50% eggshell-mixed Khorasan mortar between the stone elements had a positive influence on the earthquake and creep behaviors of both restored and yet-to-be-restored historical bridges.
Stabilizing of soils can be done with physical, chemical and hydraulic methods. Chemical stabilization is one of the most widely used method among them. In this study, low plasticity Çatalağzı clayey soil is chosen as a research material. F type of fly ash are used as a chemical additive. Soil is mixed with various amount (0%, 10%, 20% and 30%) of fly ash. Index tests (hydrometer, specific gravity, liquid limit, plastic limit and standard compaction) were performed on clayey soil. Then samples prepared with optimum water content obtained from standard compaction test were exposed to unconfined compressive strength (UCS), moisture condition value (MCV) and California bearing ratio (CBR) tests. Curing time are selected as 0, 7 and 28 days for UCS test. Curing for CBR test includes 28 days air curing and 4 days full soaking. MCV has no curing time. Addition of fly ash increase the UCS of untreated soil. UCS of samples for S10FA, S20FA and S30FA having 7 day of curing time is 1.46, 1.51 and 1.53 times of the Çatalağzı clay of having no curing time. Rate of increase in UCS gets slow down after 7 days. MCV of S10FA is 18.3 while it is 12.2 for Çatalağzı clay which means 50% increase. Fly ash content after 10% have no significant change and even decrease slightly. CBR values are increased with an addition of fly ash also. It has been concluded that this type of fly ash increases the engineering performance of untreated clay but it is not suitable to be a subgrade for highway when taking into account of CBR value
In this paper, the three-dimensional (3D) seismic plastic damage performance of the Ermenek Arch Dam (220 m), which was built in Karaman, Turkey, in 2009, is investigated by including different gallery spaces. 3D modeling of the dam is performed using the finite-difference method, and four various gallery spaces are added to the dam model considering their original oval geometries. WIPP-Drucker (WD) material model is utilized for the dam’s concrete material in creep and seismic damage analyses. Moreover, the Mohr–Coulomb material model is utilized for the foundation. Quiet nonreflecting and free-field boundary conditions are taken into account in the earthquake analyses, and reflecting (fix) boundary condition is used in the factor of safety (FOS) analyses in order to minimize the reflection of earthquake waves at the boundaries. First, the FOS analyses of the Ermenek Dam are performed considering the WD material model, and the optimum mesh space is determined according to FOS analyses. Then, 3D earthquake analyses are performed for 10 important strong ground motions that occurred in Kahramanmaraş, Hatay, Malatya, and Gaziantep in 2023. As a result of the FOS analyses, it is suggested that the mesh length of arch dams should not be chosen randomly while performing the earthquake analyses, and the FOS analyses of arch dams should be carried out using the WD material model before choosing the mesh space. Besides, it is concluded that selected ground motions for seismic analyses have created significant plastic damage around the galleries of the Ermenek Arch Dam, and gallery spaces are of great importance for the seismic plastic damage behavior of arch dams.
Khorasan mortar, a traditional, durable, and environmentally friendly building material, has been utilized for centuries in the Khorasan region of Türkiye. Its composition, which is based on natural hydraulic lime, imparts exceptional strength, breathability, and workability, making it suitable for diverse construction projects. Consequently, investigating the mechanical properties of Khorasan mortar, specifically its interaction with stone elements in historical buildings, in various mixing ratios, can provide valuable insights into the preservation and future of these architectural treasures. This study focuses on researching Khorasan mortar as a material of interest, utilizing brick ballast, lime, standard sand, water, and egg white, with a particular emphasis on egg white-stabilized Khorasan mortar. Four different water contents (70%, 80%, 90%, and 100%) were carefully selected, based on the dry mass of the egg white, to prepare a total of 12 samples (three identical samples for each water content) for testing. Prior to testing, the samples were cured for seven days in a desiccator. Unconfined compression strength tests were conducted, and axial strain-stress graphs were plotted to determine the unconfined compression strength (UCS) of the mixtures. The results revealed that the mixtures containing 80% water content exhibited the highest UCS values, while the samples with 90% and 100% water content demonstrated similar UCS values. The minimum UCS was approximately 0.518 times the maximum value, suggesting the importance of optimizing the water amount in Khorasan mortar formulations.
In the present study, the bearing capacities of coarse graded soils beneath the strip foundations were calculated by means of analytical and numerical methods. First all necessary geotechnical properties of the soil were achieved at seven different relative density values of the soil in terms of correlations between friction angle () and dry density (d). Second, 63 bearing capacity analyses of strip foundation systems were conducted by changing the soil parameters and the width of the foundations with analytical and finite element methods (FEM). The Mohr-Coulomb, elastic-plastic, model was chosen for this research. Although explicit analytic solutions were obtained without any difficulty, FEM provided only the load-deformation response at the base of the footing from the models. Because of that, some prediction methods were used to evaluate and find the bearing capacity of the soils beneath the foundation from the load-deformation responses. The results of analytic and numerical analyses of strip foundation laying on loose soil models gave very similar values. Although, very similar bearing capacity values of the foundations laying on dense soil models were calculated from the analytical methods, the results of numerical methods were very divergent and scattered at the same conditions. The reason for this is due to some limitations of the elastic-plastic model and prediction methods.
Shallow strip footings are essential to carry loads from structures. Load bearing capacity factors can be calculated both by the field tests (plate load test) and numerically. Bearing capacity factors are the main parameters that affect the bearing capacity of any foundations. Nγ, one of these factors, have significant impact. Increase in internal frictional angle (ϕ), causes enhance the Nγ value. However, after ϕ value reaches 30°, dramatic increase is observed. This make the bearing capacity values complicated. In this study, strip foundation on surface resting on sandy soils were designed with a Geostudio 2012 software. Various foundation width (1, 1.25, 1.5, 1.75 and 2 m) and internal friction angle (29°, 31°, 33°, 35°, 37°, 39°, and 41°) was selected. Bearing capacity values were calculated with both numerical (software) and analytical methods. After, Nγ values of analytical methods were compared to results obtained from software. Results indicate that, Biarez 1961 has the average Nγ values while Terzaghi (1943) and Michalowski (1997) have the maximum. Nγ value obtained from numerical analysis (finite element method) increased with an increase in foundation width also. Values from finite element method is average of other analytical methods when B = 1.25 m, while Nγ values of numerical methods are the biggest when B = 2 m.
