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Item A COMPARATIVE STUDY ON RESOURCE LEVELING CAPABILITIES OF COMMERCIAL PROJECT MANAGEMENT SOFTWARE PACKAGES FOR PROJECTS WITH RESOURCE CONSTRAINTS(2022-01-14) Hussein Farooq Albayati, Noor; Aminbakhsh, SamanIn construction project management the critical path method (CPM) is the most commonly used technique for project scheduling. Although this technique provides many advantages for project managers, it cannot efficiently deal with the allocation of the resources. Therefore, other techniques have been introduced to address resource allocation requirements of the projects. Of these techniques, Resource Leveling aims to minimize the fluctuation in resource usage histograms obtained by CPM without violating the resource constraints, while securing the shortest CPM duration. Resource leveling is vital for effective utilization of project resources (e.g., manpower, machinery, and equipment) as it helps precluding intermittent usage of the resources. Keeping the resource usage at a relatively constant level would result in a decrease in the overall project cost as the additional costs required to demobilize and remobilize the resources will be minimized. The main objective of this study is to analyze effectiveness and efficiency of the most widely used commercial project management software packages in solving resource leveling problems with constrained resources. To this end, the most recent versions – as per the date of this study – of three software packages, namely, Microsoft Project Professional 2019, Primavera P6 Professional 2019, and Asta Powerproject version 15.0.01.489 are examined. The performance of the practiced software are evaluated based on thirteen different priority rules over a set of problem instances available in the literature. The practiced problems include 640 instances providing a diverse combination of network complexity, activity number, and resource type number. Results obtained by the software are also compared with the solutions provided by the Serial Scheduling Scheme – a heuristic method. The findings of the leveling process reveal while all the three software packages manage to provide comparable results, Asta PowerProject transpire to be the all-round best performing method while Primavera sports the fastest leveling module. This study also sheds light on the challenges and practical hurdles to utilization of the aforementioned software for resource leveling purposes.Item A META-HEURISTIC FOR THE DISCRETE TIME-COST-QUALITY TRADE-OFF PROBLEM WITH GENERALIZED PRECEDENCE RELATIONSHIPS(2022-01-14) Abdulsattar, Abdulrahman M.; Aminbakhsh, SamanBuilding projects can certainly be considered as one of the most crucial elements that contributes greatly to economic growth of a nation. They facilitate developments in other industries too by providing appropriate working spaces and the means for mobilization of resources (e.g., office building, hospitals, schools, highways). Through unique public or private bids, the governments and stakeholders aim to achieve reasonable prices for such projects with minimum possible makespans and the best quality. Evidently, weighing the available offers and coming up with an optimal decision can pose challenges for the decision-makers. In this regard, generation of a tool that helps decision-makers strike a proper balance among the conflicting project objectives (i.e., time, cost, and quality) is imperative. To this end, this study proposes a method which assists in selection of the best compromise choices among the options available for each of the project activities. In addition to time and cost, the proposed method is designed to bring the quality aspect into the equation as well. To quantify the quality, a value referring to the weighted importance and performance of each activity is used. The proposed method is based on a slightly modified Genetic Algorithm (GA) that incorporates the domination concept for selection of the best solutions out of the potential candidates. The GA-based method is capable of handling unlimited number of precedence relationships for each activity and above all, it is able to capture and unravel any type of logical relationship. This very feature significantly improves the practical relevance of this research as parallelization of activities is a common practice in real-life projects. Planners by benefitting from the various types of relationships (i.e., Start-to-Start, Start-to-Finish, Finish-to-Start, and Finish-to Finish) and the concept of lag time frequently introduce parallelization into the network. Overlapped activities, in turn, help reduce the unwanted idle times and speed up the project significantly. In order to demonstrate the application and to evaluate the effectiveness of the proposed model, it is used for solution of three different Time-Cost-Quality (TCQ) tradeoff problems, two of which are generated within the context of this thesis. The practiced instances include a small benchmark TCQ problem with 18 activities taken from the literature in addition to more complex 29- and 63-activity TCQ problems produced herein based on existing 29- and 63-activity time-cost tradeoff problems, respectively. The obtained results reveal both the effectiveness of the proposed model and the possibility to be used by the planners amidst making arduous decisions.Item A STUDY ON MODELING SOIL-STRUCTURE INTERACTION EFFECTS IN BUILDINGS(2022-02-14) Al-dayyeni, Nawaf Hani Muslim; Sönmez, ErtanSoil-structure interaction is usually not considered in the design of most buildings in civil engineering practice. Based on the assumption that these effects reduce the base shear (and the overall earthquake load) for most building structures and soil conditions due to period lengthening, omission of soil-structure effects is in general considered to be conservative and the buildings are designed as fixed base structures. This assumption does not hold for certain building structures and soil conditions (e.g., massive structures, tall buildings, and structures on soft soil). In this thesis, soil-structure interaction effects in buildings are studied using relatively simple models prepared by a general-purpose structural analysis software (SAP2000). A symmetrical, 6-story, 6-bay reinforced concrete moment resisting frame is considered for both two-dimensional (2D) and three-dimensional (3D) building models. Seismic responses of three different building structures (with varying dynamic characteristics) on three different homogeneous, elastic soil mediums are computed and compared with the responses of the corresponding fixed base models. Soil-structure interaction effects are modeled by two approaches: (i) using soil springs representing the soil impedance functions (substructure method), and (ii) modeling the soil medium directly along with the structure and the foundation (direct analysis method). Two types of foundation are considered in the models: footing foundation (i.e., isolated footings) and raft foundation. ASCE 7-10 acceleration response spectra are determined based on the soil properties and used to examine the seismic response of the models considered. A limited study is also performed by time-history analyses using an actual earthquake ground acceleration record (1940 El Centro). Analyses of 2D and 3D models showed the well-known period lengthening effect of soil-structure interaction clearly. The results of this study indicate that spring models based on soil impedance functions that are widely used in practice lead to a lesser period lengthening effect compared to direct models. Similarly, by examining the base shear, story displacement, story drift, and foundation settlement results, it is observed that the soil-structure interaction effects were more significant in the direct models compared to the spring models.Item AN INVESTIGATION FOR THE RESIDUAL STRENGTH OF REMOULDED CLAY SPECIMENS RECOVERED FROM ORDUKÖY LANDSLIDE IN NORTHERN TURKEY(2017-01-07) Mekael, Ahmad; Akış, Ebru; Yılmaz, M. TolgaLandslides are among the frequent natural disasters in Turkey. In order to take effective remedial measures for active landslides, their mechanism should be accurately modeled for analyses. The uncertainty regarding the residual shear strength on failure plane is a significant issue to be solved for a reliable model. The residual shear strength can be measured by multi-reversal direct shear tests and ring shear tests in laboratories, and by vane tests on the sites of landslides. In the scope of this study, the residual shear strength of remoulded clay specimens recovered from a landslide in Sinop Province of Turkey is investigated by the multi-reversal direct shear test results. Atterberg limits for clay specimens are LL=64, PI=43 and clay fraction in the specimens is 59.5%. A big consolidation box has been built to reduce the total time necessary for consolidation before shearing, and to solve the issues relevant to squeezing the very soft remoulded clay in direct shear box, and to prepare uniform specimens for testing. Multi-reversal direct shear tests on consolidated specimens were run with shearing rates ranging from 0.0007 mm/min to 0.024 mm/min. The number of shearing cycles was ranging from 5 to 9. The set of normal stress included the figures 51.1, 102.2, and 204.4 kPa. The rate effect on residual shear strength was observed in the tests, and a number of preliminary observations on this effect was explained for consideration in future testing studies. In this study, the residual friction angle is supposed to be the secant friction angle (c=0) during mobilization of residual strength. The secant friction angle is estimated to be ranging from 11.7° to 13.2° . The limitations of this study are criticized. The estimated range of angle of residual strength was observed to be reasonably consistent with empirical relationships presented in literature and with the figures estimated according to the limit-equilibrium analyses of the landslide.Item AN INVESTIGATION OF DRAINED SHEAR STRENGTH OF OVERCONSOLIDATED HIGH PLASTICITY CLAYS(2022-01-13) Yaşar, İrem; Akış, Ebru; Yılmaz, M. TolgaIn the design and analyses of geotechnical structures, drained or undrained shear strength parameters of the clays are used depending on the drainage conditions. In short term, such as during rapid construction of embankments or foundation on clays or at the end of construction of excavation in clay the undrained shear strength parameters should be used. Whereas, when the excess pore water pressure is completely dissipated, the analysis can be carried out in terms of effective stresses. Therefore, the drained shear parameters are used in the design of foundations, retaining structures and slope stability analyses. In this thesis, experiments are conducted to investigate the drained shear strength parameters of remolded high plastic clays (CH) which are collected from the Atılım University campus. Atterberg limits and the clay fraction of the soil samples are determined as LL= 62%, PI= 36% and CF=46%, respectively. In this research, there are two different experimental studies to investigate the shear strength parameters by using direct shear tests, since then they are the most widely used laboratory tests to determine these parameters. In the first test series, the drying effect on the peak and residual shear strength parameters is investigated by using multi-reversal direct shear tests with a newly developed resistance system. In the first part of these tests, a normally consolidated high plastic clay sample at the liquid limit is prepared and multireversal direct shear tests are conducted at 0.035mm/min shearing rate under 300 kPa. The soil sample is heated to dry out before shearing. The peak and residual shear strength determined by tests on wet samples are compared with those of dry samples. It is seen that the water content effect on the peak and residual shear strength that have been already reported in the literature is observed in the first multi-reversal direct shear tests. A decrease in water content results in an increase in peak and residual strength values. In the second part, multi-reversal tests under 200 kPa normal stress are performed on a lightly overconsolidated (OCR=1.5) soil sample at a slower rate (0.0035mm/min) but after residual strength is reached, the soil specimen heated and sheared one more time to investigate the change in residual shear strength. It is seen that the decrease in water content of the soil that has been reached to the residual state does not affect the residual shear strength of the soil. In the second test series, drained direct shear tests are performed on soil samples having different OCR values to predict an empirical correlation between drained shear strength of overconsolidated and normally consolidated clays. The direct shear tests are conducted on soil samples that are prepared at OCR=1, 2, 4 and 7 under normal stresses 50 kPa, 100 kPa and 200 kPa and the shearing rate of these tests are set as to 0.0018mm/min. The test results are evaluated and the prediction equation is presented.Item AN INVESTIGATION ON THE MECHANICAL PROPERTIES AND BEHAVIOR OF EXPANDED POLYSTYRENE (EPS) GEOFOAM(2022-01-24) Güven, Güral; Akış, EbruExpanded polystyrene (EPS) geofoam blocks have been used for various purposes in civil engineering applications. The initial elastic modulus and compressive strength are considered to be the two most significant engineering properties of these materials for modeling and design. In the first part of this study, unconfined compression tests on EPS geofoam samples having different shapes (cubic or disc), dimensions (50 mm, 100 mm and 300 mm for cubic samples and diameters of 50 mm, 65 mm and 100 mm with different aspect ratios for disc samples) and densities (14, 22 and 26 kg/m3 ) are performed to determine initial elastic modulus and compressive strength. 356 unconfined compression tests with different loading rates are performed. In the second part, 294 of the test results obtained in the first part are used to predict the initial elastic modulus and the compressive strength of EPS geofoam by using regression analysis. Predicted strength values at 5% strain (σ5) and 10% strain (σ10) were excellently correlated with real values by higher than 0.96 R2 values for both cubic and disc samples. The R2 value is 0.94 for initial modulus of elasticity (𝐸𝑖 ), strength values at 1% strain (σ1) for cubic samples whereas the figure is 0.76 for disc samples. To predict reliable 𝐸𝑖 and σ1 values for disc specimens between effecting parameters, a previously developed ANN (artificial neural network) algorithm is used. The rest of the test results are used to compare the results of predicted figures from the regression analyses and ANN algorithm. ANN algorithm successfully predicted the initial modulus of elasticity (𝐸𝑖 ), the strength values at 1% strain (σ1) outputs with R2 values of 0.9874 and 0.9876 respectively.Item ANALYTICAL INVESTIGATION OF MULTI-LAYER COMPOSITE TUBES SUBJECT TO PRESSURE(2010-01-27) ATLI, Ahmet; AKIŞ, TolgaThe aim of this study is to present an analytical approach for the stress analysis of multi-layer composite tubes under internal and external pressure. The expressions of stresses and displacements for single, two and three-layer tubes are obtained and the critical cases of yielding are examined using Tresca’s and von Mises yield criterion. The analytical solutions are checked numerically for different material sets and the stress and displacement distributions are obtained. It is found that yielding begins at the inner surface of the single layer tubes under internal or external pressure. For the two-layer tubes, yielding may begin at the inner surface of the inner or outer tubes or simultaneously at both locations. For the three layer tubes different cases of yielding may occur depending on the material properties. In the study, the conditions for these various yielding cases are thoroughly examined.Item BEHAVIOR OF BOLTED TENSION SPLICE CONNECTIONS IN STEEL LATTICE OVERHEAD TRANSMISSION LINE TOWERS(2014-11-06) ŞEN, Gökmen; AKIŞ, Tolga; BARAN, ErayBehavior of bolted splice connections in steel lattice overhead transmission line towers under tensile loads was experimentally studied. Seven specimens with each of them having a different connection detail were tested. The main parameters used in the testing program were the number of bolts used in the connection, presence of connection reinforcement angles, and the number and geometry of filler plates used between the main members. Main aim of the study was to gain a better understanding of the load-flow mechanism in the connection. The specimens were observed to exhibit similar response, which includes an initial linear behavior followed by a yielding portion and a secondary linear portion that continues until net section fracture of the upper main member. The measured load capacities of specimens were compared to the predicted capacity corresponding to the net section fracture of the upper main member. The measured and predicted capacities were observed to agree acceptably well with each other. Based on the experimental results, the redundant members in the connection were identified and recommendations were provided in order to simplify the connection geometry by eliminating the redundant members.Item BEHAVIOR OF HIGH STRENGTH SHEAR CONNECTORS EMBEDDED IN CONCRETE(2022-02-14) WARDI, ADIL HADI WARDI; Tunç, Gökhan; Ibraheem, KhalilThe push-out sample consists of a small part of steel column. It is linked to a concrete wall through its both sides by connectors resisting shear force. The slip between the wall and the steel is measured at changing load increments or displacements. In this thesis, the structural behavior of three different types of shear connectors (Headed stud, L-shaped, and Channel) with ordinary and high strength steel properties embedded in different types of concrete (ordinary concrete, high strength concrete, and reactive powder concrete) was studied. The objective of this study was to investigate the behavior of selected shear connectors to determine the mechanical properties of different types of concrete and study the shear stiffness of shear connectors by conducting a total of 36 push-out tests specimens. In these test specimens, three types of shear connectors, headed stud, L – shaped and channel types of connectors, with two types of bond, welded and epoxy, were used. The results of this study indicated that reactive powder concrete increased mechanical properties of concrete as the concrete age increased. The specimens, OCHW, HCHW and RCHW generated the best shear force values for normal weight, high strength, and reactive powder concrete, respectively (The first letter is used to define the type of concrete: “O” is for ordinary, “H” is for high strength and “R” is for reactive powder concrete. The second letter is used to describe the type of shear connector, “C” is for channel connecter. The third letter is used to define the steel type for shear connector, “H” is for high strength steel. The fourth and the last one is used for the type of connections between the studs and the steel plate, “W” is for Welding).thesis.listelement.badge BEHAVIOR OF PIN CONNECTIONS UNDER AXIAL LOAD(2023-01-27) YAHYA, Mustafa Ahmed; SÖNMEZ, ErtanPin connections are commonly used in engineering structures due to their simplic ity and ease of construction. Although their structural behavior and design is rel atively simple, the stress distribution due to the mechanics of two contact surfaces is actually quite complex. In design codes, the geometry of the pin connections is typically restricted by some empirical equations without any detailed information on their development. In this thesis, the behavior of pin connections under axial load is investigated by analyzing parametric finite element models and studying the effects of pin-to-hole diameter ratio, eccentricity of the hole (in axial direction), and bend ing of the pin. The contact interaction between the pin and the plate is modeled by face-to-face penalty contact formulation. The contact between the pin and the plate is assumed to be frictionless. The accuracy of models is checked via mesh sensitiv ity analyses and comparison to analytical solutions given by Hertz for non-conformal cylindrical contacts and by Persson for conformal cylindrical contact. Based on the results of analyses performed in this study, it is found that all three parameters (i.e., pin-to-hole diameter ratio, eccentricity of the hole and bending of the pin) can have significant effects on stress concentration in pin connections. Although two-dimensional models are useful in preliminary assessment and model verification, they ignore through-thickness effects that may be significant in some cases; therefore, three-dimensional models provide more accurate representation of stress distribution in the pin connections. The analyses also confirm that the analytical solutions of both Hertz and Persson gave reasonable results for smaller contact angles when pin bending effect is not present while Hertz’s solution deviates significantly from the results of finite element models with neat-fit pin having a more conformal contact surface with larger contact angles (i.e., total contact angles higher than 40◦ ).Item COMPARISON OF DIFFERENT LOAD PATTERNS FOR PERFORMANCE BASED SEISMIC RESPONSE OF BUILDINGS(2022-01-21) AL-oda, Hasan Ali Hani; Sönmez, ErtanModern seismic codes are increasingly using performance-based design methods that employ nonlinear static (pushover) and dynamic (response history) analyses to determine more realistic behavior of structures under earthquake loads. Nonlinear analysis methods consider the inelastic behavior including strength and stiffness degradation and the dynamic characteristics of the structures. Although the advancements in computer processing power have made both nonlinear static and dynamic analyses more accessible to the practicing engineers, relative simplicity of pushover analyses have made them more popular in engineering practice. In this thesis, different lateral load patterns commonly used in seismic pushover analysis are examined and their effects on the global behavior and the performance of building structures are compared. Buildings are assumed to be made of reinforced concrete. Three different building heights (3-, 7-, and 10-story) and two different layouts (regular square layout and irregular L-shape layout with re-entrant corner) are considered. Effects of infill walls are also studied for buildings with regular layout. Seismic responses of the buildings are computed using SAP2000 software by four different analysis methods: (i) linear static analysis using equivalent lateral force (ELF) method, (ii) linear response history analysis (RHA), (iii) nonlinear static (pushover) analysis, and (iv) nonlinear response history analysis. In nonlinear analyses, lumped plastic hinges at the frame element ends are employed. M3 hinges are used in beam elements and P-M2-M3 hinges are used in column elements. Hinge properties are determined in accordance with FEMA-356. Seismic loads are calculated assuming buildings were at a location having a Site Class B (rock) based on ASCE 7- 10. For response history analyses, scaled acceleration records of 1940 El Centro earthquake are used. Limited studies are also performed to investigate application of fiber hinges, softer soil conditions (Site Class C), and effects of infill walls in the 7- story building model with regular layout. Three different pushover lateral load patterns that are based on uniform acceleration (UA), fundamental mode (FM) and the method of modal combination (MMC) are considered. For each analysis method and pushover lateral load patterns, various response parameters (including performance points, story displacements, story drifts, plastic hinge locations, etc.) are computed for all models and compared with the results of other cases. The results have indicated that MMC lateral load pattern in general have better agreement with nonlinear response history analysis results compared to the other load patterns. MMC has the advantage of being a relatively simple method to establish a force pattern that includes the effects of higher modes by combination of multiple mode shapes. From comparison of the results for buildings with regular and irregular layouts, it is observed that all three load patterns give somewhat similar pushover results in regular 3-story buildings and the differences in the results become more pronounced as the number of stories (or building height) increases and when the building layout is irregular. Since the higher modes have a greater contribution to the dynamic response in irregular buildings and taller buildings, the differences between the pushover and nonlinear RHA results increase in these buildings. MMC load pattern is considered to be a more appropriate choice as it gives more accurate and reliable results due to consideration of higher modes. FM load pattern leads to higher story displacements and drifts in regular buildings and lower story displacements and drifts in irregular buildings except the 3-story building. MMC load pattern usually leads to similar or lower story displacements and drifts in all cases when compared to UA load pattern. Presence of infill walls have increased the pushover capacities of the regular buildings, increasing the base shear about 15-25 % and decreasing the corresponding roof displacement about 20-30 % at the performance point.Item COMPARISON OF HYDROLOGIC AND HYDRAULIC FLOOD ROUTING, A CASE STUDY ON THE TIGRIS RIVER(2022-01-25) Alani, Ruaa Adnan Mohammed Saeed; Yılmaz, Meriç; Karim, Ibtisam RaheemThis study deals with channel flood routing problem with two approaches: hydrologic and hydraulic flood routing using software programs HEC-HMS and HEC-RAS, respectively. For the comparison of these methods and software, a case study is carried out on a 158 km long reach on the Tigris River, between Al Shargat and Samarra Dam. With the observed inflow hydrograph of the flood event in the spring of 2019 as an input to both software, the routed outflow hydrograph is predicted. The peak discharge of the observed, HEC-HMS, and HEC-RAS outflows are obtained as 6437.00 m3 /s, 6538.70 m3 /s, and 6600.29 m3 /s, respectively. The translation of the HEC-HMS and HEC-RAS outflow hydrographs are estimated exactly the same as the observed outflow. The differences in the observed and estimated peak discharges are related with the lack of detailed data in HEC-HMS and added levees in HEC-RAS to prevent overflowing to floodplain in the study area. The observed and estimated outflow are found to be in good linear relation considering their coefficient of determination values close to 1.Item COMPRESSIVE AND TENSILE BEHAVIORS OF STEEL FIBER REINFORCED CONCRETE(2015-06-26) ABDUSSALAM, Alfadhil. A. Gheit. Alfadhil; MERTOL, Halit Cenan; BARAN, EraySteel fiber reinforced concrete (SFRC) is a concrete mixture containing discontinuous, discrete steel fibers that are randomly dispersed and uniformly distributed. The quality and quantity of steel fibers influence the mechanical properties of concrete. It is in general accepted that the addition of steel fibers significantly increases tensile toughness and ductility, also slightly enhances the compressive strength. The benefits of using steel fibers become apparent after concrete cracking because the tensile stress is then redistributed to fibers. The objective of this study is to investigate the compressive and tensile behavior of steel fibers in reinforced concrete by conducting an experimental program consisting of load testing on various specimens made from conventional concrete (CC) and steel fiber reinforced concrete (SFRC). Test series consisted of cylindrical compression (100×200 and 150×300 mm) and prismatic modulus of rupture (150×150×600 mm) specimens. Tensile tests on reinforcing bars surrounded by prismatic concrete specimens were also performed. The variables used in these tests were lengths (500, 1000, and 1500 mm) and cross sectional dimensions (60×60, 100×100,150×150, 200×200 mm) of the prismatic concrete specimens around reinforcing bar. Load-deflection behaviors were obtained and evaluated to develop the compressive and tensile stress-strain relationships of SFRC. Experimental load-deflection relationships obtained from modulus of rupture tests were compared to the predicted load-deflection curves determined using compressive and tensile stress-strain curves obtained in this research. Also the stress-strain relationships available in the literature were used predict the behavior.Item DETERMINATION OF THE OPTIMUM SHEAR WALL AREA TO FLOOR AREA RATIO FOR REINFORCED CONCRETE BUILDINGS(2022-02-14) Al-Ageedi, Mustafa Khalid Abdullah; Tunç, GökhanDue to the abundance and severity of earthquakes, there is an urgent need to study the seismic analysis and design of buildings. In this thesis, a structural analysis was conducted to determine the optimum ratio of shear wall areas in a reinforced concrete building. For this purpose, a total of 20 models were generated with varying building and wall dimensions. Twenty and thirty story buildings were selected to understand the effect of varying building heights on their structural behavior. A parametric study on shear wall areas was conducted using different shear wall area to floor area ratios. Building models, therefore, included no wall and some walls with 0.5%, 1% and 1.5% area ratios applied in both x and y directions. Each of these models were subjected to response spectrum analysis using the forces generated according to 2019 dated Turkish Earthquake Code (TEC 19) and 2016 dated American Building Code (ASCE 7-16). The buildings were assumed to be all office buildings located in a severe seismic zone, Avcilar, Istanbul. The thirty story building due to its total height had to be considered tall as per the requirements in TEC 19. The additional requirements were also included in the analysis to understand the impact of tall buildings on optimum shear wall determination. The following parameters were investigated for the optimum shear wall area to floor area ratio: (a) building periods, (b) base shear and shear force resisted by all shear walls, and (c) deflection and story drifts. The results indicated that the ratio of shear wall equal to 1.5% produces the optimum solution.Item DEVELOPMENT OF STEEL-CONCRETE HYBRID CONNECTIONS FOR PRECAST CONCRETE MOMENT-RESISTING FRAMES(2013-06-21) KURTOĞLU, Metin; BARAN, Eray; BARAN, MehmetHybrid beam-column connection details to be used in precast concrete moment resisting frames were developed in this study. Experimental part of the study included testing of fourteen precast concrete beam-column connection specimens utilizing the proposed hybrid connections and two monolithic beam-column connection specimens under reversed cyclic loading. Strength, stiffness, energy dissipation capacity and ductility characteristics of the specimens were examined by evaluating the test results. The effect of various parameters including the geometry of steel connection components, amount of bolt pretension to be used at the connection region, method of anchoring the connection components in beam elements, and the detailing of beam reinforcement near the connection region on the behavior of the beam-column connection region was investigated. After producing useful experimental evidence, further analytical studies were conducted in an attempt to study the behavior of typical precast concrete structural systems made of moment resisting frames under lateral load effects. Within this context, finite element models of three- and five-story planar frames were prepared and lateral nonlinear static pushover analyses were conducted on these models. The experimental and analytical studies revealed that the proposed hybrid precast concrete beam-column connection details offer the potential of providing a performance comparable to their monolithic counterparts.Item DYNAMIC AND STATIC ANALYSES OF THE OIL AND GAS PIPELINES(2014-07-09) HASSAN, Marwan Adil; SARI, Yasin DursunIn this study, a numerical calculation on interaction between soil and steel pipelines was performed. Properties of soil and pipe may cause significant effects on the movements of buried pipelines. To improve the understanding of the behavior of buried pipelines subjected to dynamic and static loading, different oil and gas pipes have been considered in this study. Earthquake load of magnitude 5.4 with time shaking of 10 sec and surface loads (50, 100, 150 and 200 kPa) have been used. To simulate numerically this effects, 2D finite element method PLAXIS is performed. The results are discussed and fitted by univariate linear and non-linear analysis. Some influential factors such as soil types (clay, loose and dense sand), soil layers (one, two and three soil layers), underground water table, static water loads (of height 20m above soil), burying depth, pipe diameter and pipe thickness are discussed in details. Based on the results, it can be concluded that these factors are important items on pipeline displacement for both static and dynamic loads. Some significant comparisons and conclusions are drawn.Item EFFECT OF WATER CONTENT ON THE STRENGTH PROPERTIES OF KUFA LIMESTONE QUARRY(2022-01-26) AL-SALIHI, ALI FAROOQ MOHAMMED SALIH; Özgenoğlu, Abdurrahim; Al-Adilee, Amjad Ibrahim FadhilWater content has a negative effect on both physical and mechanical properties of rock materials and rock masses. The influence of water on the mechanical behavior of rocks can be problematic for the stability of rock mass in different civil and mining structures. The main objective of this thesis is to investigate the effect of water content on uniaxial compressive strength and indirect tensile strength of limestone of Kufa quarry. This thesis also relates the uniaxial compressive strength to indirect tensile strength test to use indirect strength tests to estimate the strength of specimens as a function of degree of saturation to use it in design and classification purposes of Kufa quarry limestone in Iraq. Furthermore, meaningful relationships between degree of saturation of specimens with uniaxial compressive strength, deformability parameters, and both of point load strength index and Brazilian test were developed. One hundred and twenty five specimens collected from the same zone in Kufa quarry limestone in Iraq were prepared for some mechanical tests according to American Society for Testing Materials (ASTM). Their physical properties were determined (bulk density, porosity, and specific gravity) and tested under uniaxial compressive, point load, and indirect tensile tests for different degree of saturations (0%, 25%, 50%, 75%, and fully saturated).According to the results a significant decrease was observed in strength test results and modulus of elasticity with an increase in water content. The maximum decreases in uniaxial compressive strength, point load strength index, Brazilian test, average and tangent modulus of elasticity were determined as 33%, 80%, 75%, 87% and 74% respectively for fully saturated specimens.Empirical equations developed as correlations between the uniaxial compressive strength and tensile strength, point load strength index, and modulus of elasticity under the five degrees of saturation. Another correlation obtained between the degree of saturation with compressive strength, tensile strength, point load strength index, also the modulus of elasticity. As well as a correlation between tensile strength and point load strength index were developed. Point load strength index has a better correlation with uniaxial compressive strength than Brazilian tensile strength. The correlation between point load strength index and Brazilian tensile strength was not good.Item ENHANCING CIVIL ENGINEERING EDUCATION USING ACTIVE LEARNING TECHNIQUES(2013-08-14) ÇALIŞKAN, Nihan Tuğba; MERTOL, Halit CenanIn the last few decades the civil engineering prefession has rapidly developed to be able to adapt to changing conditions in various areas worldwide. Besides, the 21st century students are also completely different from the students who lived in the 20th century. The advances in technology have a great influence on these students. They don’t know the life before computer, cell phones etc. The traditional educational methods containing passive teaching methods no longer work for current students. Most of the students in this century are active learners and active teaching methods should be used to be able to get good performance from these students. In this study computer games, hands-on-practices, experiments, laboratory works used as active teaching methods and applied on different courses such as Statics, Dynamics, Strength of Materials, and Fundamentals of Reinforced Concrete, and the change in students’ performance is evaluated.Item EVALUATION OF ENHANCED PUSHOVER ANALYSIS PROCEDURES FOR REGULAR AND IRREGULAR REINFORCED CONCRETE BUILDINGS(2022-01-14) ELSHARIDA, Mohamed; MERTOL, Halit CenanAn important aspect of performance-based design methodologies can be regarded as the accuracy of predictions of seismic demands parameters. Making improvements to this aspect of the design-based methodologies is undeniably desirable. Recently, several Enhanced Pushover Analysis (EPA) procedures that take into account the influence of higher modes have been proposed. As most of these procedures have been applied to regular building frames; there remains a need to verify the efficiency of such procedures on the evaluation of irregular building frames. The EPA procedures, namely the Consecutive Modal Pushover (CMP), Dynamic Load Pattern (DLP), and Single‐Run Multimode Pushover (SMP), have been applied to regular steel moment resisting frames in literature. The purpose of this study is to comparatively assess the efficiency and capability of these EPA procedures to estimate the seismic demands of twelve regular and irregular special reinforced concrete (RC) moment-resisting frames having various number of stories (4, 8, 12, 16, 20, and 24). The structural responses given by the EPA methods are then compared with the benchmark results achieved from the Nonlinear Time History Analysis (NLTHA). For the sake of comparison, the conventional pushover analyses based on the first-mode and uniform lateral load pattern are also demonstrated. The results indicate that the DLP and CMP methods can predict the seismic demands of regular and irregular buildings with a higher level of accuracy than the SMP procedure. Consequently, the DLP and CMP procedures were found to be better alternatives for obtaining practically reasonable estimations of seismic demands of building frames where the influence of higher modes is significant.Item EVALUATION OF MODIFIED AND EXTENDED PUSHOVER METHODS FOR RC BUILDINGS HAVING SETBACK IRREGULARITY(2022-09-12) HASAN, Ghadeer; MERTOL, Halit CenanIrregular configurations of reinforced concrete buildings were frequently identified as one of the main causes of failures during previous earthquakes. The setback irregularity which occurs due to abrupt reduction of the lateral dimension of the building at specific levels of elevation may be catastrophic for buildings having various heights. Engineers are more likely to adopt simplified nonlinear static analytical procedures such as pushover analysis when evaluating the seismic performance of reinforced concrete buildings due to its ease in application. The use of conventional pushover analysis methods provides acceptable results low-rise buildings. However, these methods do not provide sufficient results for mid- and high rise buildings whose behavior under seismic actions is not only governed by the fundamental mode shape. To overcome this problem, some advanced methods considering the effects of higher mode shapes were proposed by various researchers. However, the applicability of these methods to three dimensional high-rise buildings having setback irregularity was not addressed in the literature. In this study, a total of 6 mid- and high-rise building models having setback irregularity at various locations were analyzed using nonlinear pushover analysis methods namely the Inverted Triangular Lateral Load Pattern (TLP) according to ASCE 7-22, First Modal Shape Lateral Load Pattern (FLP), Uniform Lateral Load Pattern (ULP), Modified Upper Bound Method (MUB), and Extended Upper Bound Method (EUB), to evaluate the applicability of these methods. The results obtained using these methods were compared to the Nonlinear Time History Analysis Method (NLTHA) which provided benchmark solutions to the problems. Three of the building models had 6 stories and the other three had 12 stories. The story heights of the models were all 4.5 m at the ground story and 3.2 m for the rest of the stories. All models had four bays in both plan view directions with a typical length of 6 m each. One model of each height level was a regular building and used for comparison purposes. Other two models of each height level had setback irregularity in various locations of the elevation in one direction. The results were assessed for seismic demand variables such as lateral displacements, interstory drift ratios, and plastic hinge rotations. The EUB method also provided more accurate results of interstory drift ratios of all irregular building models compared to those of the conventional pushover analysis procedures (TLP, FLP, and ULP). Conventional pushover methods were not sufficient to predict the plastic hinge rotations at the upper stories of the 6 and 12 story building models, whereas the EUB method provided reasonable estimates of these plastic hinge rotationsfor irregular buildings.