Search

The construction industry in many developing countries is considered the main engine for economic growth. Quantification of the resilience of the construction industry in developing economies is essential for stakeholders and decision makers. Many researchers have attempted to quantify the construction industry's resilience in the context of developed economies; however, there is lack of established measures of such quantification in developing countries. This paper proposes a framework for the composition of an index that quantifies the resilience of the construction industry in developing countries. The proposed framework is demonstrated in the context of three developing countries: Rwanda, Egypt, and Turkey. The index is composed of measures such as the construction value added to a country's gross domestic product (GDP) and employment in construction. Principal Component Analysis (PCA) is utilized for weighting and aggregation of the individual variables. Studying the causal relationship between construction growth and economic development from 1971 to 2022, results show that construction growth leads to economic development in each of the three countries. Results of the proposed index values indicate that the construction industry in each of the three countries demonstrated increased resilience by sustaining both its outputs and its employment generation aspect in the two years following the coronavirus pandemic in 2019. Quantification of the construction industry's resilience in countries where the construction growth leads to the economic growth would provide a crucial insight for stakeholders and decision makers. [ABSTRACT FROM AUTHOR]

A new realm in spatial planning defies administrative boundaries and adopts larger territories than cities, which encompasses city clusters where cities can both compete and cooperate rather than compete as individual entities. In that regard, various approaches to the delineation of functional regions and "mega" regions have been proposed in time, based on population and employment, the urban landscape, or the interactions between regions in terms of intracity travel or migration flows. This paper proposes a methodology to delineate functional regions as well as megaregions based on the pattern of intercity freight flows and a composite economic indicator, exemplified by a case study of Turkey. A four-step delineation method is proposed in which population and trips are used initially to rank the cities and their hinterlands. Second, hierarchical clustering is carried out to delineate new clusters based on flows, and the resulting clusters are used to delineate functional regions for regional planning purposes. Third, a composite economic indicator (income and wealth index, IWI) is employed to refine and finalize the boundaries, thus ensuring the functional zones' homogeneity as economic clusters. In the last step, megaregions are pinpointed based on the cities of the functional regions using two criteria: IWI (≥0.4089) and GDP (TRY ≥18.3 million) in 2015. The defined regions represent a new geographical scale in regional planning that can aid the central government in addressing leading regional issues: for example, prioritizing governmental investments that are subsidized by national funds aimed at the alleviation of regional inequalities. A future study may focus on the effect of regional economic inequalities on internal migration flows. [ABSTRACT FROM AUTHOR]

Following the proclamation of the Republic of Turkey in 1923, one of the most important urban planning and architectural projects of Mustafa Kemal Atatürk's national program was the establishment and development of a new capital city called Ankara. During these formative years, Ankara underwent a major program of architectural urbanism and modernism that visually set the young republic apart from its recent Ottoman past. This paper will attempt to examine historical precedents in capital city planning via a cross-country analysis to that of Ankara; however, it will also highlight the extant literature and contribute to the argument that Ankara provides a unique experience in modernism, urbanism, and especially nation-building in the 20th century. Although Turkey's political and national direction has taken a new course in the early 21st century, the Kemalist strategy in communicating national identity and nation-building continues to be emulated and communicated in state-sponsored architecture in Ankara. [ABSTRACT FROM AUTHOR]

Turkey, which is a country with rapid population growth, has a housing problem with low-income groups, that particularly emerged due to urbanization. Different solutions have been used in an attempt to solve this problem, within the scope of social housing policies that the local or central governments have produced. However, social housing policies have been insufficient to solve the rapidly changing housing problem due to the social, political, and economic dynamics of Turkey. Some social housing policies have succeeded; however, some have accelerated the formation of illegal settlements. Although the most important component of this multidimensional process is generally the government, actors, such as users, architects, and construction companies, whose expectations and effects are different from each other are the components of the process. It is uncommon for the user to have a say in the design, or production, or both of a house. This is true for Turkey and many countries worldwide. This paper aims to achieve a centralized view of the production of housing for low-income groups in Turkey, which is quite complicated and problematic; and to draw attention to the potential of user participation that has not previously had a place in this process and to open the issue to discussion. First, a literature review will be conducted that focuses on discourses in the late 1960s and early 1970s, where user participation in low-cost housing production was on the agenda. Later, to revise the existing large framework in the context of Turkey, social housing policies that were developed by the governments to solve the housing demands of low-income groups will be briefly reviewed. Finally, the effect of user participation in the process of social housing for low-income groups in Turkey will be discussed through the best practices believed to be from three practical experiments. The aim is to raise awareness about user participation in low-cost housing production in Turkey which is not currently on the agenda. [ABSTRACT FROM AUTHOR]

Construction is considered as one of the highly fragmented, inefficient, and low-performing industries. Enterprise resource planning (ERP) systems have been used to overcome such problems. However, due to a number of technical and organizational barriers, ERP implementation is very challenging. The major objective of the research reported in this paper is to explore the critical success factors (CSFs) of ERP implementation in the construction industry in developing countries. In this respect, based on an extensive literature review, 14 CSFs were identified and a questionnaire survey was conducted to analyze the role of those CSFs on the performance of ERP implementation. The data is collected from 90 construction firms from Turkey. The statistical analysis results show that top management support and commitment, clear goals and objectives, project team competence, effectiveness of the project leader, and cooperation between team members are the most significant drivers of success. Factor analysis was also employed on the data and the findings suggest three dimensions, namely (1) human factors, (2) organization, and (3) technology. Findings of the research reported in this paper are expected to help senior managers and consultants implement ERP systems in construction firms in an effective manner. [ABSTRACT FROM AUTHOR]

The significant damage observed during recent earthquakes resulting from liquefaction of shallow saturated soil deposits beneath structures has illustrated the need for further research in the area of liquefaction-induced ground movement effects. This study used the shake table facility at the University of California, San Diego to evaluate the liquefaction-induced settlement of a shallow foundation founded on top of liquefiable ground conditions. To study the seismic performance of a shallow rigid foundation, two large-scale shake table tests were conducted using different input motions with varying peak accelerations. The experimental model comprised three soil layers and included a shallow foundation seated over an unsaturated crust layer underlain by saturated loose and dense layers. The model ground was based on similar subsurface ground conditions observed in recent earthquakes in New Zealand, Japan, and Turkey. The seismic response of the model foundation and the soil was captured through intensive instrumentation. The main purpose of this study was to better understand the contributing mechanisms in liquefaction-induced settlement of buildings during strong shaking. Results from this series of tests were used to explore different liquefaction mitigation countermeasures; this study served as a baseline for two follow-on shake table tests which are not discussed in this paper. Detailed discussions of the excess pore-water pressure generation and dissipation, and its effect on the contributing mechanisms of liquefaction-induced settlement are presented, along with the application of standardized cumulative absolute velocity as an intensity measure to estimate the amount of liquefaction-induced settlement. The flow velocity calculation due to hydraulic transient gradient indicated an upward flow in the loose layer, which explains the observed sand ejecta. Measured and estimated foundation settlements were compared using simplified procedures. The observed foundation settlement generally was higher than the estimated settlement. This series of large-scale shake table tests provides a unique benchmark for calibration of numerical models, and simplified procedures to reliably estimate liquefaction-induced building settlements. Future mitigation tests can be evaluated using the results of this baseline experimental study. [ABSTRACT FROM AUTHOR]

The aim of this paper is to present the field investigation and performance assessment of the mosques and minarets constructed around the cities of Elaziğ and Malatya and their surrounding districts shortly after the earthquake (magnitude of MW=6.5–6.8 according to different institutions) that occurred at 8:55 p.m. local time on Friday January 24, 2020, in the Sivrice township of Elazığ, located in the southwest of the Eastern Anatolia region of Turkey. Mosques and minarets are special structures affected by earthquakes as other buildings too. Two types of mosques and minarets constructed using masonry and reinforced concrete constructional materials and technologies were investigated. A total of 20 mosques with minarets having either a masonry or reinforced concrete carrier system were extensively examined. It is concluded that a significant part of the collapsed and damaged mosques and minarets did not receive adequate engineering services and/or were constructed without following national guidelines. Also, it is thought that the absence of any codes or guidelines for these special structures is a major deficiency and leaves engineers in a difficult position during the design phase. [ABSTRACT FROM AUTHOR]

This paper aims to define trends and dominant modes in annual instantaneous maximum flows (AIMF) covering the period 1961–2014 from 10 gauge stations located in different river basins in Turkey. To achieve this aim, discrete wavelet transform (DWT) and additive wavelet transform (AWT) in conjunction with the Mann-Kendall (MK) test are used and compared for the first time. Moreover, global wavelet spectrum (GWS) is employed to test the significance of the most effective periodic components. The sequential MK test is also used to determine the start or change points of trend in AIMF series. From the MK trend results, five stations showed a statistically significant (at a 5% level) negative trend for AIMF series and short-term periodic components (2 and 4 years) were found to be the most effective components, which are responsible for producing a real trend founded on the data series. The GWS analysis indicated that the most dominant components identified are significant. In addition, the MK- z values of the most effective periods derived from AWT generally showed a better agreement with MK- z value of original time series with higher correlation coefficient compared to those of DWT. The sequential MK graphs of the AWT-based time series also produced a better harmony with the sequential MK of the original data. Finally, the results showed AWT coupled with the MK provided a very efficient and accurate analysis for defining the most effective modes in the AIMF series and can be successfully used in any hydrological time series. [ABSTRACT FROM AUTHOR]

This paper presents a study of the hydrodynamic stability of a submerged floating pipeline (SFP) under regular waves. Generally, pipelines submerged in water are constructed as the seabed type, using the immersed method. However, in the Turkey and Cyprus Project, which was completed in 2015, pipelines that traverse water depths of up to 1,500 m were constructed using the suspended method for offshore crossings to ensure economic feasibility. This study investigated the behavior and response characteristics of submerged floating pipelines using the buoyancy to weight ratio, the tendon anchoring method, and the wave incidence angle by finite-element analysis. When the influence of the waves increases as the SFP approaches the free surface, the SFP has large deformation due to the material properties of the pipe. Installed depth was very important because the effect of wave for SFP decreases according to increasing of the water depth. The proposed analysis method produced good results. It can be applied as an evaluation of global behavior in the design phase. [ABSTRACT FROM AUTHOR]

This paper presents a study of liquefaction-induced lateral ground displacements along the coast of Izmit Bay during the 1999 Kocaeli (Izmit)-Turkey earthquake. The paper discusses: (1) observed ground displacements after the earthquake, (2) the results of field investigations by means of borings and in situ index tests, including standard penetration tests, static cone penetration tests, and piezocone tests, (3) analyses of expected lateral displacements using two empirical models and one semiempirical model, and (4) comparisons between observed and calculated lateral ground movements. The three models provide inconsistent predictions of observed lateral ground displacements, with one method overpredicting and two methods both overpredicting and underpredicting observed lateral ground displacements by large amounts. Thus, it appears that there is a need for improved engineering tools for prediction of small to moderately significant lateral ground displacements (lateral displacements of approximately 0.1-2.5 m) at soil sites with similar ground characteristics to the case history sites presented herein. [ABSTRACT FROM AUTHOR]

The paper investigates the structural performance of a seven-story reinforced concrete (RC) building that collapsed during the Van (Turkey) earthquake on October 23, 2011, using nonlinear static and dynamic methods. The selected RC building has two blocks and was designed according to the Turkish Earthquake Code (TEC) in 1975. The site investigation included sections and steel detailing and soil and concrete properties taken after the earthquake. The pushover and nonlinear time history analyses of the building were completed using the existing plan and test and observation data. It is concluded that the building collapses both analysis types. [ABSTRACT FROM AUTHOR]

During the past several decades, many studies illustrated the importance of socioeconomic factors on interregional migration in different countries. Interregional migration has had an immense impact on Turkey's population dynamics after the 1950s. This study aims at investigating the patterns of interregional migration in Turkey during the period of 2008 to 2010 using a hierarchical cluster analysis. First, the paper gives background information about interregional migration by providing the ratios of immigration and emigration with respect to the population and the characteristics of the regions between 2007 and 2010. Second, interregional immigration and emigration flows are investigated by the use of a hierarchical clustering analysis with different linkage techniques, e.g., single, complete, average, and others, which determine how the distance between two clusters should be defined to represent actual partitioning. Then, the best partitioning of the regions is selected based on a popular internal or unsupervised criterion, called cophenetic correlation. According to the results obtained by the single linkage that yielded the highest cophenetic correlation, the country's largest city, Istanbul, dominates the largest cluster of the country consisting of the regions from east to west both immigration and emigration flows. These analyses have shed light on the complex relationship of the interregional migration in Turkey. Regional inequalities can be overcome first by understanding this complex relationship of the interregional migration in the country. Then, under a national strategic development plan, public investments can be directed more to, and private investments can be encouraged in, underdeveloped regions via the tool of economic subsidies in order to create economic sustainability across the regions throughout the country. [ABSTRACT FROM AUTHOR]

The aim of this paper is to propose a decision support tool for contractors before the bidding stage to quantify the probability of delay in construction projects in Turkey by using the relative importance index (RII) method incorporated into fuzzy logic. For this purpose, 83 delay factors were identified, categorized into 9 major groups through a detailed literature review process as well as interviews with experts from the construction industry. The relative importance of these delay factors and groups was quantified by using the relative importance index method. The ranking of the factors and groups was demonstrated according to their level of effect on delay. A delay assessment model was proposed using the fuzzy set theory by taking into account the delay factors characterized in construction projects. The assessment model was developed using a commercial software product. The proposed methodology was tested in a real case study; and the probability of the delay of the project was evaluated by means of the assessment model after the required inputs were entered into the software. The factors and groups that contribute most to the probability of delays were discussed depending on the case study results. The assessment model results were found to be satisfactory. Finally, some recommendations were made in order to minimize and control delays in construction projects. [ABSTRACT FROM AUTHOR]

The 2023 Türkiye-Syria earthquake sequence is one of the biggest disasters Türkiye has ever encountered. The loss of lives and properties by the earthquake indicates that the country was not prepared for such a level of disaster. Moving forward, it is critical for Türkiye to prioritize effective disaster recovery efforts and foster a culture of disaster resilience. Disaster recovery is a multifaceted, complex issue that requires effective planning, coordination, well-defined objectives, and community support to succeed. The present study focuses on proposing a recovery framework for affected areas in Türkiye based on a review of existing recovery mechanisms as well as lessons learned from previous recovery efforts in Türkiye and in Chile, Japan, and Nepal. It also includes the outcomes of focused ground discussions and field interviews conducted during the post-2015 earthquake recovery phase in Nepal and during the 2023 reconnaissance study in Türkiye. This study underscores the significance of implementing the "leave no one behind" principle of the Sustainable Development Goals (SDGs) alongside community participation, strong institutional leadership, quality-focused reconstruction, capacity building, building code enforcement, and retrofitting as essential components of an effective and comprehensive recovery strategy. The study serves as a valuable resource for policymakers, decision makers, development partners, and various stakeholders engaged in the recovery process. [ABSTRACT FROM AUTHOR]

Drought forecasting is a critical aspect of water resource management, where droughts have substantial economic and environmental impacts. This study employs a Monte Carlo–based approach, complemented by statistical distribution fitting and trend analysis, to forecast future streamflows on long-narrow type drainage basins. Therefore, the Kızılırmak River Basin in Turkey, which is a long and narrow type, has been selected to test the suggested method. Historical data are used to determine the best-fitting distributions, ensuring reliability in the selection of future streamflow scenarios also using trend analysis. The study reveals valuable insights into potential drought occurrences over the next 25 years, aiding decision makers in implementing water management strategies. Based on the analysis results, it is expected that the drought frequency is increased up to 64.7%. Drought severity is classified into different categories, offering an understanding of drought characteristics. The findings contribute to effective water resource planning by aiming the assessment of future hydrological droughts. [ABSTRACT FROM AUTHOR]

Lean construction is the term that corresponds to the reflection of the production system developed at the Toyota Corporation (automotive industry) on the construction industry. Turkish contractors constitute a large portion of the local economy and are important global actors in contracting business. Lean construction-based research and practice, as a production management-based approach for increasing the effectiveness and efficiency of the construction industry, are scarce among Turkish contractors. This paper presents the results of a questionnaire prepared to predict the lean conformance levels of Turkish contractors and discusses the results. The comparative strengths and weaknesses of Turkish contractors for a lean construction initiative are highlighted. The findings that are presented in this paper can be used as a starting point to disseminate the research and practice in lean construction among Turkish contractors in the future. A similar kind of research can be repeated to compare the lean conformance levels in different countries and to evaluate the lean construction programs at different companies after the introduction of lean construction. [ABSTRACT FROM AUTHOR]

Construction delays are common in construction industry and create major concerns for project performance. Construction delays are caused by many factors. The aim of this paper is to identify delay factors on construction projects and analyze these factors with the relative importance index method. For this purpose, 83 different delay factors were identified, categorized into nine major groups, and visualized by the Ishikawa (fishbone) diagram through detailed literature review and interviews with experts from the construction industry. The relative importances of these delay factors were quantified by the relative importance index method. The ranking of the factors and groups were demonstrated according to their importance level on delay. According to the case study results, the factors and groups contributing the most to delays (those needing attention) were discussed, and some recommendations were made to minimize and control delays in construction projects. [ABSTRACT FROM AUTHOR]

Urban transformation projects are discussed in terms of the level of realization of the aim targeted by the actors. Neglect of transparency in the project phases and insufficient participation of all actors give rise to problems that cause resistance of the actors, provoke social disturbances, and hinder implementation. To minimize these problems, this paper presents a method for objective evaluation of multiactor projects that encompasses questioning the achievement level of the initial project aims set by the project actors. For this process, this study used the analytic hierarchy process in two case studies, both in Istanbul, Turkey. As a result, the method and principle in this paper can provide a theoretical method to measure and supervise the multiactor project's success in a way that more consistently realizes the transparency and accordance of the actors. To ensure a 60% achievement rate among all actors, or at least ensure a healthy settlement structure and preserve and renew the historic and cultural sites and local architecture, taking measures against natural disaster risks and improving urban living standards should be realized in these case studies. [ABSTRACT FROM AUTHOR]

The built environments of metropolitan areas are rapidly changing in response to urban development dynamics. The nature of the urban built environment continues to be influenced by the conflicting interests and expectations of various entities involved in the process of development planning and implementation. The formulation and implementation of urban development plans in Turkey is guided by the statutory provisions of the country's planning system. This process has led to piecemeal implementation through partial plans and plan amendments in metropolitan areas. This article attempts to determine how the private sector in metropoles in Turkey shaped the built environment in Turkey after 1980. Influence of neo-liberal policies and a partial planning approach set by a free-market economy instead of a comprehensive planning approach shaped urban space. As a capital, the urban development of Ankara has mostly been shaped by partial planning approaches and implementations and uncontrolled developments, especially on the southwest axis of the city's metropolitan area. For this reason, one of the largest settlement of southwest Ankara is the Angora Settlement, which has been selected as the case study. Examining the entities who play a part in the urban development process is important to control its consequences. In this article, the case of Angora Settlement is used to question the planning process and entities in the development of urban built environments, and studies this settlement to identify and question which entities determine the components of the built environment in the urban development process. In particular, this paper captures the dominance of the structural interests of the private sector in shaping Angora's land use pattern, which is important because it reveals the uncontrolled growth dynamics in developing countries. [ABSTRACT FROM AUTHOR]

Transportation-disadvantaged groups have been defined in previous studies as those who are low income earners, are family dependent, have limited access to private motor vehicles and public transport services, and are obliged to spend relatively more time and money on their trips. Additionally the disabled, young, and elderly are commonly considered to be among the transportation-disadvantaged. Although generally this definition seems correct, it is not specific enough to become a universal definition that could apply to all urban contexts. This paper investigates whether perceptions of travel difficulty vary as does the definition of transportation-disadvantaged in socioculturally different urban contexts. For this investigation, the writers undertake a series of statistical analyses in a case study of Yamaga, Japan, and compare the findings with a previous case study, in which the same methodology, hypothesis, and assumptions were applied to a culturally and demographically different settlement in Aydin, Turkey. After comparing the findings observed in Aydin with the statistical analysis results in Yamaga, this paper reveals that there can be no detailed, universal definition of the transportation-disadvantaged. The writers conclude that the characteristics of the transportation-disadvantaged are not globally identical, and policies and solutions that work in one locality may not have the same results in another sociocultural context. [ABSTRACT FROM AUTHOR]

It is important to find a tool to be found that is capable of fulfilling specific functions (such as land assembly, self-finance, the protection of social capital, with results obtainable within a certain time) in approaches related to the renewal of urban built-up areas. This paper discusses whether land readjustment (LR) can be such a tool by analyzing whether it performs better than traditional urban renewal processes in Turkey, and whether LR may be an instrument in different contexts of renewal. This paper focuses on three built-up housing areas with different characteristics, and is based on the results of two different questionnaire surveys. The first survey was conducted in municipalities in both metropolitan areas and large cities in Turkey and covered specific urban renewal projects. The second survey was distributed to residents from some renewal project areas including three built-up housing areas with different characteristics in Istanbul. All discussions contribute to an improved understanding of the potential of the LR method as a tool for urban renewal projects. [ABSTRACT FROM AUTHOR]

Following the 1999 Marmara earthquakes, urban regeneration has gained particular importance in redevelopment of housing areas particularly in historical districts of Istanbul. Local governments, upon new roles and responsibilities regarding postdisaster conditions as well as the changing global trends, called for innovative planning approaches which involve the community. In this respect, some questions are raised in the planning agenda: While performing the new roles, what kind of institutional changes should local governments experience? How should local community be involved in this process? The paper considers the conditions of spatial and community change in realizing urban regeneration as a collaborative action through the case study of Matra—Regeneration of Istanbul Metropolitan Area (Matra REGIMA) project which highlights the fundamental capacity building requirement for both local government practitioners and the community in order to achieve the necessary actions. Consequently, this study highlights the strengths and limitations of the capacity building program applied in Zeytinburnu toward implications for future collaborative actions within urban regeneration schemes. [ABSTRACT FROM AUTHOR]

This paper presents the analytical modeling, modal testing, and finite-element model updating for a two-span masonry arch bridge. An Ottoman masonry arch bridge built in the 19th century and located at Camlihemsin, Rize, Turkey is selected as an example. Analytical modal analysis is performed on the developed 3D finite-element model of the bridge to obtain dynamic characteristics. The ambient vibration tests are conducted under natural excitation such as human walking. The operational modal analysis is carried out using peak picking method in the frequency domain and stochastic subspace identification method in the time domain, and dynamic characteristics (natural frequencies, mode shapes, and damping ratios) are determined experimentally. Finite-element model of the bridge is updated to minimize the differences between analytically and experimentally estimated dynamic characteristics by changing boundary conditions. At the end of the study, maximum differences in the natural frequencies are reduced on average from 18 to 7% and a good agreement is found between analytical and experimental dynamic characteristics after finite-element model updating. [ABSTRACT FROM AUTHOR]

The heuristic method is one of the methods used for the scheduling of resource-constrained projects. This method is commonly used in programming the projects with high number of activities and resources such as construction investments. This paper investigates the effectiveness of three heuristic method priority rules applied in the resource scheduling of ten Turkish housing estate projects which were scheduled according to three preselected priority rules [maximum remaining path length (MRPL), latest finish time (LFT), and minimum slack time (MNSLCK)] in resource-constrained conditions. The performance of each priority rule was evaluated in relation to the duration of the project. The results revealed that MRPL priority reduced the project duration to minimum in six projects, whereas LFT priority yielded the best duration results in three projects and MNSLCK priority in only one project. [ABSTRACT FROM AUTHOR]

This paper describes an arch type steel footbridge, its analytical modeling, modal testing, finite-element model updating, and dynamic analysis. A modern steel footbridge which has an arch type structural system and is located on the Karadeniz coast road in Trabzon, Turkey is selected as an application. An analytical modal analysis is performed on the developed three-dimensional finite-element model of footbridge to provide analytical frequencies and mode shapes. Field ambient vibration tests on the footbridge deck under natural excitation such as human walking and traffic loads are conducted. The output-only modal parameter identification is carried out by using peak picking of the average normalized power spectral densities in the frequency domain and stochastic subspace identification in the time domain, and dynamic characteristics such as natural frequencies, mode shapes, and damping ratios are determined. The finite-element model of the footbridge is updated to minimize the differences between analytically and experimentally estimated modal properties by changing some uncertain modeling parameters such as material properties. Dynamic analyses of the footbridge before and after finite-element model updating are performed using the 1992 Erzincan earthquake record. At the end of the study, maximum differences in the natural frequencies are reduced from 22 to only 5% and good agreement is found between analytical and experimental dynamic characteristics such as natural frequencies and mode shapes by model updating. Also, maximum displacements and principal stresses before and after model updating are compared with each other. [ABSTRACT FROM AUTHOR]

This paper presents one of the most comprehensive tests conducted about the real-time kinematics (RTK) and continuously operating reference stations (CORS) network using instruments from three global positioning system (GPS) manufacturers (Leica, Topcon, and Trimble). The test was carried out between August and October 2006 in the Marmara Region of Turkey as part of the research project for establishing RTK CORS network covering all of Turkey. Three GPS networks (NET-120, NET-90, and NET-60) were designed, each consisting of six CORS points: with interstation distances of 120, 90, and 60 km, respectively. Leica, Trimble, and Topcon directly participated in the tests, each company contributing a 2 week effort. RTK surveys were compiled at check points (previously known points) and new points were generally selected in built-up areas. Flachen Korrectur parameter—Spatial correction parameters, virtual reference stations, pseudoreference stations, and master auxiliary concept techniques were used for RTK positioning. Postprocessing by network solution software was also used at check points. The results of network-based RTK and postprocessing were found to be successful at each net, the main exception being the difficulties encountered by one of the firms participating at NET-120. Results are discussed in the paper. [ABSTRACT FROM AUTHOR]

In this paper, preliminary support design of a tunnel was analyzed by numerical and empirical approaches. The case study for this analysis is a tunnel to be constructed on the Bilecik-Istanbul roadway in Turkey. The rock mass properties of the tunnel route and design support recommendations were obtained by using an empirical approach. The rock mass properties obtained from the empirical method were used as input parameters for the numerical analysis. The empirical and numerical results, in terms of support design, were evaluated. It was seen that the numerical analysis results supported by empirical values were logical and reliable. [ABSTRACT FROM AUTHOR]

Transportation models have not been adequate in addressing severe long-term urban transportation problems that transportation disadvantaged groups overwhelmingly encounter, and the negative impacts of transportation on the disadvantaged have not been effectively considered in the modeling studies. Therefore this paper aims to develop a transportation modeling approach in order to understand the travel patterns of the transportation disadvantaged, and help in developing policies to solve the problems of the disadvantaged. Effectiveness of this approach is tested in a pilot study in Aydin, Turkey. After determining disadvantaged groups by a series of spatial and statistical analyses, the approach is integrated with a travel demand model. The model is run for both disadvantaged and nondisadvantaged populations to examine the differences between their travel behaviors. The findings of the pilot study reveal that almost two thirds of the population is disadvantaged, and this modeling approach could be particularly useful in disadvantage-sensitive planning studies to deploy relevant land use and transportation policies for disadvantaged groups. [ABSTRACT FROM AUTHOR]

The article comments on the study about the subsurface characterization at ground failure sites in Adapazari, Turkey during the Kocaeli earthquake that hit the place in August 1999. It was reported that during the study, sporadic boils were observed at a few of the case sites and were classified as silty sand with few exceptions. The sand layers are generally deeper and appear to be too dense and an explanation states that the sediment ejecta could have been carried to the surface by the liquefied loose sand.

Computer aided design (CAD) technology is one of the most influential information technology (IT) innovations of the last four decades. This paper studies the factors that influence the spread of this important IT innovation in the context of the Turkish architectural design practice. It builds on the innovation diffusion theory which proposes that internal (i.e., copying behaviors of others) and external influence (i.e., complying with clients’ requirements, changes in government regulations, demand conditions, and consulting firms’ suggestions) factors drive diffusion of an innovation. The paper empirically tests the propositions of innovation diffusion theory by using three mathematical models: The internal influence model, the external influence model, and the mixed influence model. Research findings point out that the mixed influence model has the highest exploratory power. They show that the diffusion of CAD technology in architectural design practice is primarily driven by internal rather than external influence factors. This study is of importance to researchers because this is the first application of the influence models to the study of the diffusion of CAD technology in architectural design practice. It is also of relevance to design practitioners since the findings should provide a useful guide in their decision to adopt or not to adopt CAD technology. [ABSTRACT FROM AUTHOR]

Ground failure in Adapazari, Turkey during the 1999 Kocaeli earthquake was severe. Hundreds of structures settled, slid, tilted, and collapsed due in part to liquefaction and ground softening. Ground failure was more severe adjacent to and under buildings. The soils that led to severe building damage were generally low plasticity silts. In this paper, the results of a comprehensive investigation of the soils of Adapazari, which included cone penetration test (CPT) profiles followed by borings with standard penetration tests (SPTs) and soil index tests, are presented. The effects of subsurface conditions on the occurrence of ground failure and its resulting effect on building performance are explored through representative case histories. CPT- and SPT-based liquefaction triggering procedures adequately identified soils that liquefied if the clay-size criterion of the Chinese criteria was disregarded. The CPT was able to identify thin seams of loose liquefiable silt, and the SPT (with retrieved samples) allowed for reliable evaluation of the liquefaction susceptibility of fine-grained soils. A well-documented database of in situ and index testing is now available for incorporating in future CPT- and SPT-based liquefaction triggering correlations. [ABSTRACT FROM AUTHOR]

Whether extensively planned or not, all companies have a strategic perspective which is analogous to the personality of an individual. However, a clear strategic perspective is a must to achieve strategic integration that further leads to competitive advantage. In order to define a strategic perspective, four determinants should be put together: objectives, strategies; competencies; and competitive rules. There are two way linkages among objectives, strategies, and competencies that are affected from competitive forces acting on the market and these interrelations change with respect to company characteristics like size, age, major client, etc. The objective of this paper is to propose a conceptual framework for the analysis of a strategic perspective and present results of a questionnaire carried out to explore the strategic perspectives of Turkish contractors. Objectives, strategies, and competencies of Turkish contractors are analyzed together with competitive rules prevailing in the Turkish construction industry. The determinants of strategic perspective can further be used as a guide for setting a strategic agenda for construction companies with different characteristics and operating in different submarkets. [ABSTRACT FROM AUTHOR]

The stability and structural performance of aged structures under extreme events are rarely investigated. The severe deterioration in current condition of aged bridges can trigger premature failures under regular floods or even mild earthquakes. A reliable bridge inspection program is required for condition assessment. Currently, Turkey, a seismically active country, does not have a regular bridge inspection program or management systems. This deficiency was highlighted by the collapse of the Caycuma Bridge in 2012, killing 15 people during a regular flood event. The main contribution of this paper is to identify the need for in-depth investigation of aging bridges by integration of bridge inspection data with bridge seismic fragility curves and to address the seismic vulnerability of these bridges with a high level of scour. In this scope, one of the inspected bridges has been selected to determine the loss of seismic load resistance attributable to floods. The investigation has included use of newly developed bridge fragility curves for Turkey and advanced nonlinear analysis. [ABSTRACT FROM AUTHOR]

This paper conducts a catchment-scale analysis of extreme rainfall events of the reference (1961-1990) and three future climate periods (2013-2039, 2040-2070, and 2071-2100) for Rize Province, Turkey. The extreme value theory (EVT) is applied to analyze observational and projected extreme rainfall data including regional climate model (RCM) outputs guided by two general circulation models (GCM) under SRES-A2 and RCP8.5 greenhouse gas scenarios. A new rapid and effective bias correction method is also developed and applied to adjust the climate models simulations. The EVT analysis results demonstrated significant differences between the model runs for both the reference and future periods with considerable spatial variability in rainfall extremes. Based upon the assembled mean results, approximately a 30% decrease in the median value of extreme rainfall events is projected over the study region for the near future, 2013-2039, and middle of the century. This change dramatically decreases to 15% of its historic value at the end of the century. The results from the implemented GCM-RCM combinations revealed that more intense rainfalls are produced by the combination forced by the RCP8.5 scenario. In addition, the results from goodness-of-fit tests among different distribution models showed that general extreme value distribution can be used appropriately to characterize the behavior of projected extreme rainfalls over the study region. [ABSTRACT FROM AUTHOR]

All over the world, governments, policy makers, and practitioners are searching for proper routes and corridors to invest transportation infrastructures such as new railways, highways, and multimodal ways. Although it is one of the important steps of development, finding a suitable route for new transport infrastructure is a complicated and conflicting task for of various reasons. Possible social and environmental impacts on society and increasing cost and technical pressures on decision makers are some of these reasons. Taking into consideration aspects of different evaluation criteria, a geographic information system (GIS)-based multicriteria solution approach is proposed in this study. Potential high-speed rail (HSR) routes in Turkey are considered as a case study. After gathering and processing the related GIS data, weights are assigned to each criterion by using the fuzzy analytic hierarchy process in order to indicate their relative importance. Then, the additive ratio assessment method is applied to carry out the multicriteria (13 technical, social, and demographic criteria) evaluation and selection of the suitable alternatives (among 20 HSR routes) under given circumstances. It was found that the corridor from the west part of Turkey (from İzmir and Manisa) to the Marmara region (Kocaeli and İstanbul) had the highest priority, followed by the corridor from Ankara to Kayseri. HSR trains could potentially reduce the journey times to Kocaeli and İstanbul from İzmir and Manisa, as compared with driving, by 46% and 45%, respectively. The results of this study can be used to evaluate potential HSR corridors/routes or similar transport infrastructures in other countries. [ABSTRACT FROM AUTHOR]

In the last 30 years, there have been various findings related to the effects of construction investments––especially housing investments––on the economic development of urban areas. However, the impact of public housing investments on economic development in rapidly and dynamically developing countries with high housing demand has not been sufficiently discussed. This article presents an examination of the impact of housing production as a public housing investment on the economic development of provinces at the macro level through the case of Turkey. In the study, we analyzed the impact of public housing investments on the economic development of the provinces in Turkey between 2004 and 2018. Since 2004, Turkey has pursued a policy of increasing public housing investments, and for this purpose, the structure of the Toplu Konut İdaresi Başkanlığı (TOKI––the Mass Housing Authority), which is a strong and autonomous centralized public institution, has changed. Despite the increase in public housing investment at the country level as a result of this policy, the effect of public housing investment on economic growth at the provincial level has not been determined. In this study, panel data analysis methods were applied, regression analyses were conducted, and the findings were evaluated. The findings of the analyses showed that, although housing investments (private sector) have had an impact on the development of the provinces at the macro level, public housing investment and production have not played a decisive role in the economic development of the provinces. [ABSTRACT FROM AUTHOR]

A civil engineer who lacks motivation, may perform poorly in making decisions, which may in turn negatively affect the performance of a construction project. This study extends knowledge about individual-level motivation among civil engineers and the relationship between the motivation of civil engineers and their demographics (i.e., age, marital status, education, work experience, type of company, project value). A questionnaire survey was administered to Turkish civil engineers in order to collect data on their personal demographics and their perceptions of the importance of different motivators. The case of Turkey is investigated because a large number of Turkish contractors are major players in international markets. This paper argues that there are statistically significant differences in the perception of some motivators by civil engineers based on their demographics and that different individuals need to be motivated by different motivators. The study demonstrates the existence of a relationship between demographics and motivators, an area that is mostly ignored in the motivation literature. Higher executives in the construction industry, who understand this relationship, may be able to motivate their engineers individually rather than using blanket motivators for all engineers. [ABSTRACT FROM AUTHOR]

This study argues that businesses, as principal units of both the economy and the urban environment, show different performances in the postdisaster period that in turn affect the community-level recovery. To this end, the paper examines the long-term recovery process of businesses through empirical research in Adapazari, Turkey, which was greatly challenged by the 1999 earthquake. A total of 232 respondent firms there were selected through stratified random sampling. Data were gathered via questionnaire designed to identify the factors that determined their success during the recovery process. It is hypothesized that the recovery performance of businesses is affected by a number of factors that are categorized thus: internal factors, response capacity, and the extent of damage within the business recovery model. The findings of the study indicate that business recovery is associated positively with operating in the finance, insurance, and real estate (FIRE) sector, but negatively correlated with operating in the trade and service sectors, and with variables expressing the states of being financially in trouble and taking more damage. A policy frame is provided for the integration of business recovery into community recovery by focusing on the predictors of business vulnerability and loss. [ABSTRACT FROM AUTHOR]

Sustainability has become a major concern for the construction industry. There has been a growing emphasis on green buildings in the last decade. Renovation is critical in terms of improving the energy efficiency of the building stock. In this paper, the green building certification process of existing buildings in developing countries is investigated. A qualitative case study methodology has been employed to gain a better understanding of the critical success factors of the greening and certification process. In this respect, six leadership in energy and environmental design (LEED)-certified projects in Turkey are examined. A framework is used to analyze the components of this process, including the drivers, resources, green implementations, barriers, enablers, benefits, and impacts. Unavailability of approved materials, poor design of the buildings, and difficulties with the documentation process have been major barriers. The barriers have been overcome through the commitment of the owners, top management support, and collaborative working among project parties. The findings of this study are expected to guide construction professionals in certifying existing buildings in an effective manner. Similar studies may be conducted for existing buildings in different countries, where different regulations and conditions exist. The proposed framework can also be employed to investigate the certification process of new construction projects. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to determine the radiological hazard level of various commercial scrap piles in Turkey. Samples were taken from metal scrap yards near the city of Istanbul, Turkey. In this study, radioactivity measurements were carried out on these samples. The activities of , , , and were determined in the laboratory by gamma-ray spectrometry. The highest , , , and activities were found to be 8,735, 465, 524, and , respectively, in residues of technologically enhanced, naturally occurring radioactive material (TENORM) scraps. Radiation doses due to gamma exposure and radon emanation from residues were determined. Site-specific test results were determined to be less than the exemption limits for external radiation. According to these results, external radiation doses were less than for workers. The main factors due to radon inhalation were based on measured effective radium content, mass, and areal exhalation rates as well as the radon emanation power. [ABSTRACT FROM AUTHOR]

The article presents a commentary of the article "Liquefaction-Induced Lateral Spreading at Izmit Bay During the Kocaeli (Izmit)-Turkey Earthquake," by K. Onder Cetin, T. Leslie Youd, Raymond B. Seed, Jonathan D. Bray, Jonathan P. Stewart, H. Turan Durgunoglu, W. Lettis and M. Tolga Yilmaz. It aims to argue that the soil liquefaction had to be validated to be necessarily involved for the reported ground deformations to occur for each case at the outset since the applicability of the methodologies tested depends on this factor. It also identifies the mechanisms contributing to the observed deformations.

Current national occupational safety and health (OSH) initiatives follow reactive approaches, i.e., if it breaks, fix it. Existing accounts, however, failed to improve national OSH performances substantially, which imposes the need for an in-depth and proactive (fix it so it will not break) investigation of national occupational fatality risks. Despite many studies examining the fatality risk of workers based on project-, company-, and/or behavior-related factors, the role of national conditions on the countrywide fatality risk of workers has not been explored. The present research leverages the national statistics of Turkey to examine their influence on construction workers' fatality risk through a machine learning–based prediction model. Several widely used machine learning methods were adopted for determining whether the upcoming month poses a significant fatality risk for construction workers or not based on national statistics of the previous month. According to analysis results, the gradient boosting decision tree algorithm yielded the highest prediction performance in terms of f1-score. The recently developed game theory–based Shapley Additive Explanations (SHAP) algorithm was used to identify whether and how national conditions affect countrywide fatality risk of construction workers. Findings illustrate that the share of the construction sector in employment, market demand, and labor shortage are the most significant national factors in determining the fatality risk. SHAP summary and SHAP dependence plots are further presented to provide decision makers with a clearer understanding of hidden relationships between fatality risk and national conditions. In addition, a framework that can be practically used by policy makers and governmental authorities is developed to help minimize national occupational fatality risk. Overall, predicting national fatality risk in the industry and identifying the national precursors of occupational fatalities contribute to the development of macrolevel safety improvements based on country-specific conditions. [ABSTRACT FROM AUTHOR]

This paper investigates the multicenter development course of Istanbul based upon urban travel patterns in the city. The spatial distribution of population and employment between 1970 and 2000 illustrated a decentralizing trend in the urban structure. Hierarchical clustering analysis was used to determine relatively homogenous groups of interactions and to explain the interaction patterns among the districts. The results of the study supported the multicenter development at the lower level on both continents (Asia and Europe), and at the upper level between the continents. Determination of efficient locations of new subcenters was suggested for further research. [ABSTRACT FROM AUTHOR]

The Berke Arch Dam is the highest arch dam constructed in Turkey. The dam height is 201 m, and the crest length is 270 m. This paper describes the Berke Arch Dam, its finite-element modeling, ambient vibration testing, finite-element model calibration, and earthquake behavior before and after model calibration. First, three-dimensional (3D) models of dam-reservoir-foundation interaction were developed to obtain analytical dynamic characteristics, such as natural frequencies and mode shapes using the Ansys finite-element program. In the analyses, reservoir water was represented by a Lagrangian approach. Then, ambient vibration tests were conducted on the dam on 4 days in May 2009 to obtain experimental dynamic characteristics. In ambient vibration tests, the sensitive accelerometers were placed on several points on the arch dam, and signals were collected from accelerometers. The enhanced frequency domain decomposition technique was used in the extraction of experimental natural frequencies, mode shapes, and damping ratios. After that, 3D finite-element models of the Berke Arch Dam were calibrated using ambient vibration test results. Finally, earthquake behaviors of initial and calibrated models of the Berke Arch Dam were obtained using the Adana-Ceyhan Earthquake in 1998. It was observed that model calibration affects the results considerably. [ABSTRACT FROM AUTHOR]

The Bosphorus Strait is a typical example of a narrow sea strait and, in general, has a two-layer flow structure. Driven by the water level difference between the Black Sea (north) and the Sea of Marmara (south), a lighter upper layer flows from north to south. A denser lower layer flow is caused by the density difference between the adjacent seas and flows in the opposite direction. In this study, the three-dimensional (3D) flow structure of the Bosphorus strait was modeled using the MIKE 3 hydrodynamic numerical code. Selecting the drag coefficient , buoyancy parameter , and turbulence Prandtl number as calibration parameters, the model was calibrated using genetic algorithms with available current measurements at three different depths for one given location. The root-mean-square errors of the calibrated model were calculated to be 0.266, 0.201, and 0.163 m/s at the depths considered, respectively. The model was also validated temporally, for four different time periods and spatially, at another location in the strait. The validated models show good overall agreement with the field measurements. This paper is also relevant to determining the hydrodynamic design criteria of marine structures, and safe marine navigation in the waterway will be considered. [ABSTRACT FROM AUTHOR]

Water quality monitoring network design is an iterative procedure, where an existing network should be reassessed from time to time on the basis of changing environmental demands and objectives in water quality management. In recent years, the economic and financial constraints faced by monitoring agencies have led to the initiation of network reduction procedures in the space domain (i.e., the reduction of the number of stations within a network). In this regard, the dynamic programming approach (DPA) can be effectively used to determine which monitoring sites are to be preserved when the network is consolidated for a fixed number of stations. However, previous studies on the use of the DPA methodology in network redesign have not yet resolved two basic questions: (1) what is the required (optimum) number of stations to be retained in the network to best represent the basin? and (2) how many subbasins should be selected when segregating the basin into smaller units as foreseen by DPA? Accordingly, the primary objective of this paper is to modify the DPA approach to determine the optimum number of stations to be retained when consolidating a monitoring network. In previous studies, the selection of subbasins in DPA was realized basically by subjective approaches based on general experiences of the designers so that the secondary objective of the study is to expand the capabilities of DPA by utilizing a more systematic approach to subbasin identification. The previously mentioned modifications to the DPA methodology are demonstrated in the case of a water quality monitoring network in Gediz River basin along the Aegean coast of Turkey. The results obtained indicate that DPA can also be an effective tool in optimizing the number of stations to be retained in a monitoring network. [ABSTRACT FROM AUTHOR]

Forecasting streamflow is extremely significant in hydrological studies to optimize the operation of water resources systems. Upper Euphrates Basin, which is located in eastern Turkey, is a snow-dominated basin and its runoff is largely affected by snowmelt. Snowmelt is an important water resource to many aspects of hydrology, including water supply, flood control, and erosion. Selection of a suitable tool was necessary to assess potential impacts of climate change on the hydrological cycle of this region. Hydrologic models are useful tools for the prediction of runoffs and interactions among hydrological variables within the hydrologic cycle. Because of limited data availability, lumped conceptual hydrological models are often used instead of distributed hydrological models. To assess the accuracy of lumped conceptual hydrological models, this paper presents simulation results of snowmelt runoffs of Upper Euphrates Basin by using two models that use the temperature index approach to calculate snowmelt process. The Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) and Large Basin Runoff Model (LBRM) were used for this purpose. [ABSTRACT FROM AUTHOR]

This study establishes the chemical properties of blended cement pastes to understand the effect of marble and brick powders on cement chemical properties. Thus, this paper extends knowledge of construction material handling and practices. Marble and brick powder and CEM I 42.5N cement clinker have been used as materials in this work. Blended cements have been prepared with the addition of CEM I 42.5N cement clinker for marble or brick powder at the ratios of 6, 20, 21, and 35%. CEM I 42.5N cement has been used as reference cement. A total of 24 cement paste samples were mixed with blended cements and reference cements according to the Turkish standard EN 196-1, and they waited in water for 7, 28, and 90 days. The chemical properties of blended and reference cement pastes were determined through the Turkish standard EN 196-2, known as wet analysis, at the 7th, 28th, and 90th days of the curing period after they were dried and ground in the laboratory. The results show that the chemical properties of cement pastes could be enhanced with the industrial wastes that have been stored on agricultural land instead. [ABSTRACT FROM AUTHOR]

The emergence of the effective management of knowledge resources as a key factor in gaining and sustaining competitive advantage presents new challenges to construction firms. Evaluating knowledge management practices is considered one of the most important challenges facing firms in today's business environment. This paper proposes a model for evaluating the knowledge management practices of construction firms. The proposed model incorporates knowledge management concepts and multilayer perceptron (MLP) neural networks to construct an importance-comparative performance analysis (ICPA) map, a simple visual tool that can provide powerful diagnostic information to executives of construction firms. The model evaluates a firm's knowledge management practices, identifies its competitive advantages and disadvantages in each knowledge management practice, and sets priorities for managerial actions to improve knowledge management practices. A real-world case study was conducted by administering a survey to 105 construction firms operating in Turkey and is presented to illustrate the implementation and utility of the proposed model. The case study findings provided preliminary support for the validity of the proposed model. [ABSTRACT FROM AUTHOR]

Urban populations in Turkey have been growing steadily since the 1950s. As such, adequately supplying development parcels for the growing population is one of the most important responsibilities of the local governments, primarily by preparing and implementing development plans. The tools most widely used in this implementation include expropriation, voluntary application and land readjustment (LR). LR provides efficient implementations both for government and landowners when compared to expropriation and voluntary application. However, Turkish LR bears a number of weaknesses that must be addressed in order to facilitate widespread use. This paper discusses the importance of the LR method in implementation of the development plans in Turkey. Furthermore, it introduces Turkish LR method, including its primary principles and implementation phases. It concludes with the strengths and weaknesses of the method and such proposals as encouraging voluntary LR applications, providing landowners' participation in the projects, carrying out the projects based on the value instead of the area, introducing legal sanctions to provide developments after the LR implementations, constructing a web-based platform to share the experiences gained in different projects, and using Geographical Information System technologies to improve overall implementation of the LR projects. [ABSTRACT FROM AUTHOR]