Civil Engineering

Permanent URI for this collectionhttps://hdl.handle.net/10679/312

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Now showing 1 - 20 of 127

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Evaluation of code provisions for seismic performance of unachored liquid storage tanks
(2017) Erkmen, Bülent; Civil Engineering; ERKMEN, Bülent
Seismic performance of two unanchored liquid-storage tanks with tank diameter of 24.5 m and 36 m and operating liquid height of 12.2 m and 20.0 m, respectively were investigated using Coupled Eulerian-Lagrangian (CEL) and mechanical spring-mass analogy nonlinear finite element computational methods. The CEL approach includes the effects of higher modes of liquid vibration (sloshing), liquid breaking effects, and liquid-structure interaction during seismic loading. The modern seismic design provisions for liquid-storage tanks, on the other hand, are based on a mechanical spring-mass analogy. This approach neglects the higher vibration modes for the sloshing water, liquid-structure interaction, and effects of tank base uplift on seismic performance. For the tanks, base uplift histories were computed with both modeling approaches through nonlinear time history analysis performed using five recorded earthquake acceleration data. The uplift histories were compared to evaluate the adequacy of code seismic design provisions for unanchored tanks, and to determine whether the mechanical spring-mass analogy can be used to predict seismic performance of unanchored tanks. Analysis results show that the traditional mechanical spring-mass analogy, which is the basis for the current seismic design provisions, does not capture tank uplift history and its effects on dynamic loads. This approach underpredicts the total numbers of tank uplifts during seismic loading. The maximum tank base uplift computed using mechanical spring-mass analogy had an average error between 22% and 58 % for each tank. The results show that there is a need to developed a modify version of the traditional mechanical spring-mass analogy to be used for predicting seismic performance of unanchored liquid-storage tanks.
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Effect of flexural demands in the leaner columns on the column buckling strength
(Earthquake Engineering Research Institute, 2018) Özçelik, Ahmet Yiğit; Clayton, P. M.; Civil Engineering; ÖZÇELİK, Ahmet Yiğit
Leaner columns of steel frames are typically designed for axial load only and they are assumed not to contribute to the lateral stiffness of the system; however, a recent study revealed that under seismic loading leaner columns underwent significant flexural demands due to differential interstory drift demands along the building height that were not observed when traditional design methods were adopted. A parametric numerical study is conducted to quantify the reduction in column buckling strength due to these flexural demands that are not considered in design. An empirical column buckling strength reduction factor that accounts for the reduction in the column buckling strength due to flexural demands is proposed. This reduction factor can be easily implemented with traditional design approaches without considering the flexural demands in the leaner columns explicitly.
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Tension field inclination angle in steel plate shear walls with beam- connected web plates
(National Technical University of Athens, 2019) Özçelik, Ahmet Yiğit; Clayton, P.; Civil Engineering; ÖZÇELİK, Ahmet Yiğit
Steel plate shear walls (SPSWs) are an efficient lateral force-resisting system with thin infill plates, main elements resisting the lateral force, connected to beams and columns on all four edges. Upon lateral loading, thin infill plates (also known as web plates) buckle almost immediately; however, the lateral stiffness and lateral strength of SPSWs are maintained due to a mechanism called tension field action. Steel plate shear walls with beam-connected web plates (B- SPSWs) are an alternative SPSW configuration where the web plates are detached from columns and connected to beams only. As opposed to conventional SPSWs where the full tension field is observed, a partial tension field is developed in the web plates of B-SPSWs due to the difference in connectivity which alters the system behavior significantly. As SPSWs are typically modeled using simplified strip models in which the accurate determination of the tension field inclination angle is of paramount importance, an analytical study is undertaken to quantify the partial tension field inclination angle. Using validated finite element models, beam-connected web plate behavior is characterized, and an equation is proposed for the partial tension field inclination angle.
Open Access
A new embankment construction method through the analysis of possible failure mechanisms in soft soils
(International Society for Soil Mechanics and Geotechnical Engineering, 2019) Arama, Z. A.; Çinicioğlu, Safiye Feyza; Civil Engineering; ÇİNİCİOĞLU, Safiye Feyza
A new method to analyze the failure behavior of embankments on soft soils is proposed in this paper. The proposed method is based on the evaluation of stability considerations applied on a possible mechanism which can be initiated by embankment loading. The developed procedure is applied on a successive set of failure mechanisms that extend towards depth starting from the surface. The envisaged mechanism is made up of concentric half circles starting from the toe of the embankment and spreading towards the deeper soils. By partitioning the circular strips by a slip fan system originating from the center of concentric circles a system of collapse mechanism partitioned to produce finite elements is created. Available stress values at each element are found by applying the rules of the lower bound plasticity solution. Once the stresses and the dimensions of the constructed mechanism are defined stability calculations are made to find the critical depth that will result in failure for any desired embankment height. Moreover safety factors mobilized at lower depths can be calculated. © The authors and IGS: All rights reserved, 2019.
Open Access
Two-part bio-based self-healing repair agent for cement-based mortar
(International Center for Numerical Methods in Engineering, 2020) Tezer, Mustafa Mert; Bundur, Zeynep Başaran; Civil Engineering; BUNDUR, Zeynep Başaran; Tezer, Mustafa Mert
Factors affecting durability of concrete structures are generally associated with each other. Due to its brittle nature, concrete can crack under stress and these cracks are one of the main reasons for a decrease in service life in concrete structures. Therefore, it is crucial to detect and recover microcracks, then to repair them as they were developed to wider cracks. Recent research in the field of concrete materials suggested that it might be possible to develop a smart cement-based material that is capable of remediate cracks by triggering biogenic calcium carbonate (CaCO3) precipitaton. This paper summarizes a study undertaken to investigate the self-healing efficiency of Sporosarcina pasteurii (S. pasteurii) cells immobilized on both diatomaceous earth and pumice, to remediate flexural cracks on mortar in early ages (28 days after mixing). To obtain a two-phase bio additive, half of the minerals were saturated with a nutrient medium consisting of urea, corn-steep liqueur(CSL) and calcium acetate and the cells with immobilized to the other half without nutrients. Screening of the healing process was done with ultrasonic pulse velocity (UPV) testing and stereomicroscopy. With this approach, the cracks on mortar surface were sealed and the water absorption capacity of the so-called self-healed mortar decreased compared to its counterpart cracked mortar samples.
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Site response analysis in performance based approach
(Elsevier, 2024-03) Ansal, Mustafa Atilla; Tönük, G.; Sadegzadeh, Shima; Civil Engineering; ANSAL, Mustafa Atilla
A performance based approach for site response analysis requires a probabilistic approach accounting for the observed variability in soil stratification and engineering properties of the soil layers. The major variability in site-specific response analysis arises from the uncertainties induced by the (a) local seismic hazard assessment, (b) selection and scaling of the hazard compatible input earthquake time histories, (c) soil stratification and engineering properties of encountered soil and rock layers, and (d) method of site response analysis. Even though the uncertainties related to first item, local seismic hazard assessment, has primary importance on the outcome of the site-specific response analyses, the discussion in this article focuses on the possible uncertainties in selection and scaling of the hazard compatible input earthquake time histories, soil stratification, thickness, type and their engineering properties, depth of ground water table and bedrock and properties of the engineering bedrock. One alternative may be to conduct site response analyses for large number of soil profiles generated by Monte Carlo simulations using relatively large number of hazard compatible acceleration time histories to assess probabilistic performance based design acceleration spectra and acceleration time histories calculated on the ground surface with respect to different performance levels. A remaining issue may be considered as the variability induced by 1D, 2D, and 3D site response analysis.
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Automated flow rate control of extrusion for 3D concrete printing incorporating rheological parameters
(Elsevier, 2024-04) Ahi, Oğulcan; Ertunç, Özgür; Bundur, Zeynep Başaran; Bebek, Özkan; Civil Engineering; Mechanical Engineering; ERTUNÇ, Özgür; BUNDUR, Zeynep Başaran; BEBEK, Özkan; Ahi, Oğulcan
The use of inline quality assessment technologies is of great importance in meeting the consistent extrusion requirements of 3D concrete printing (3DCP) applications. This paper presents a system to regulate extrusion speed and maintain the flow rate at a target value during 3DCP processes. The system is based on a new equation that combines printing parameters and the material's rheological properties in the printing process. The proposed control strategy is designed to effectively function with various cement-based mixtures. Validation tests demonstrate that the proposed system can maintain an instantaneous flow rate within a certain range and eventually achieve a constant flow rate. During operation, the flow rate is consistently maintained around the targeted value with an average error rate of 6.7 percent. The flow rate control mechanism shows promise as a reliable and efficient solution for achieving precise and constant flow rates, regardless of the cement mix design used.
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Feature extraction for enhancing data-driven urban building energy models
(European Council on Computing in Construction (EC3), 2023) Bolluk, Muhammed Said; Seyis, Senem; Aydoğan, Reyhan; Computer Science; Civil Engineering; KAZAZOĞLU, Senem Seyis; AYDOĞAN, Reyhan; Bolluk, Muhammed Said
Building energy demand assessment plays a crucial role in designing energy-efficient building stocks. However, most studies adopting a data-driven approach feel the deficiency of datasets with building-specific information in building energy consumption estimation. Hence, the research objective of this study is to extract new features within the climate, demographic, and building use type categories and increase the accuracy of a non-parametric regression model that estimates the energy consumption of a building stock in Seattle. The results show that adding new features to the original dataset from the building use type category increased the regression results with a 6.8% less error and a 30.8% higher R2 Score. Therefore, this study shows that building energy consumption estimation can be enhanced via new feature extraction equipped with domain knowledge.
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Preface
(Springer, 2023) Atalar, C.; Çinicioğlu, Safiye Feyza; Civil Engineering; ÇİNİCİOĞLU, Safiye Feyza
N/A
Open Access
Soil liquefaction and effects on structures; case study in Adıyaman-Gölbaşı after the 06 Feb 2023 earthquakes in Türkiye
(2023-11) Ecemis, N.; Karaman, M.; Valizadeh, Hadi; Dönmez, C.; Dalgıç, K. D.; Civil Engineering; VALIZADEH, Hadı
On 06 FEB 2023, two earthquakes occurred southeast of Türkiye; Kahramanmaraş-Pazarcık (Mw=7.8) and Kahramanmaraş-Elbistan (Mw=7.6). These earthquakes caused devastating effects in 11 cities in eastern Turkey and northern Syria. This study presents the post-earthquake discoveries in three liq-uefied areas during earthquakes and four buildings in these liquefied areas in the Gölbaşı District of Adıyaman City. First, an important role of post-earthquake piezocone penetration test (CPTu) in the characterization of subsur-face conditions and assessment of liquefaction hazard is presented. Then, the ef-fect of soil liquefaction on the performance of the buildings in these regions during the earthquake was investigated. These structures consist of 3- to 6-storys on raft foundations and exhibited various structural performances. Based on the interim findings from these areas, potential factors that cause moderate to severe damage to buildings were examined, and preliminary information on the relationship between soil properties, and the performance of buildings with shallow foundations in liquefied soil is presented.
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A comparison study between 1D and 3D site response analyses based on observed earthquake acceleration records…
(National Technical University of Athens, 2023) Shamekhi, Shima; Ansal, Mustafa Atilla; Civil Engineering; ANSAL, Mustafa Atilla; Shamekhi, Shima
The characteristics of the site conditions have a very significant influence on the variation of building damage during earthquakes, thus, it is essential to evaluate and analyse the effects of site conditions. One option is to conduct site-specific response analysis to calculate the response of the soil layers by using estimated acceleration records on rock outcrop, shear wave velocity profiles, shear modulus reduction, and damping ratio curves as inputs for the encountered soil layers. The objective of the present work is to evaluate the necessity of 3D site response analysis based on the comparison among the peak ground and spectral accelerations recorded by Istanbul Rapid Response Network and Istanbul vertical array stations during the Mw=6.5 24/05/2014 Gökçeada and Ml=5.7 26/09/2019 Silivri earthquakes with the calculated accelerations by 1D and 3D site response analyses. The shear wave velocity profiles determined based on in-situ geophysical and geotechnical measurements and laboratory tests within the Istanbul Microzonation Project are revaluated adopting an optimization scheme to obtain the best fits between the recorded and calculated accelerations by 1D site response analysis. These modified shear wave velocity profiles are later used for 3D site response analyses performed taking into consideration the three components of the recorded acceleration time histories in all three directions at the bedrock level to model peak ground and spectral accelerations on the ground surface.
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Characterization of site amplification by a parametric study
(Taylor & Francis, 2023) Fercan, N. O.; Şafak, E.; Ansal, Mustafa Atilla; Civil Engineering; ANSAL, Mustafa Atilla
The reliability of Vs30 and the performance of alternative time averaged shear wave velocities (Vsz) and shear wave travel times (Ttz) at various depths, z, were investigated for the estimation of site amplification and fundamental frequency (f 0) characterization by considering the linear and nonlinear soil behavior. The study revealed that alternative parameters performed better than Vs30 and the best performing z parameters changed by switching from convex to concave theoretical profiles and by increasing ground motions. For a practical usage in site investigations, guidelines to estimate nonlinear soil amplification factor and fundamental frequency from the linear ones were presented.
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Multi-criteria decision-making model for risk management in modular construction projects
(Taylor & Francis, 2024) Khodabocus, Sabah Fatima; Seyis, Senem; Civil Engineering; KAZAZOĞLU, Senem Seyis; Khodabocus, Sabah Fatima
The modular sector needs a precise guide to determine the most efficient risk management approaches. The main research objective of this study is to develop a multi-criteria decision-making model to find the most efficient risk management approach according to the relevant risk criteria. The risk criteria and risk management approaches for modular construction projects were also identified and classified within this scope. A systematic literature review, semi-structured interviews, and open-ended questionnaires were performed for identification and classification purposes. For ranking and quantifying the identified risks and risk approaches, as well as developing the decision-making model, the Delphi method and the Analytical Hierarchy Process (AHP) were conducted. A two-round Delphi method, with eleven experts, was conducted to achieve efficient performance scores of the identified risk management approaches. The percentage standard deviation decreased, Relative Importance Index (RII), Cronbach’s alpha, and Kendall’s coefficient of concordance (Kendall’s W) were calculated to ensure the outputs’ reliability, validity, and agreement level. The AHP method opted to quantify the Delphi method outputs, solve the multi-criteria decision-making process, and develop the multi-criteria decision-making model for risk management of modular construction projects. Triangulation results show that the critical risk categories are supply chain, health and safety, stakeholders, and governmental support. Lean principles such as the Last Planner System, Value Stream Mapping, Just in Time, and Kaizen are top-rated risk management approaches. This research’s novelty is identifying and analyzing crucial risk categories, providing the relevant risk management approaches ranked according to efficiency performance, and presenting a decision-making model as a guideline for risk management of modular construction projects.
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Probabilistic seismic microzonation for ground shaking intensity, a case study in Türkiye
(Springer, 2023-10) Tönük, G.; Ansal, Mustafa Atilla; Civil Engineering; ANSAL, Mustafa Atilla
The purpose of seismic microzonation is to estimate earthquake characteristics on the ground surface based on a probabilistic approach to mitigate earthquake damage in the foreseeable future for the new buildings, as well as for the existing building stock. The probabilistic analysis and related results are very important from an engineering perspective since the nature of the problem can only be dealt with in a probabilistic manner. The uncertainties associated with these analyses may be large due to the uncertainties in source characteristics, soil profile, soil properties, and building inventory. At this stage, the probability distribution of the related earthquake parameters on the ground surface may be determined based on hazard-compatible input acceleration-time histories, site profiles, and dynamic soil properties. One option, the variability in earthquake source and path effects may be considered using a large number of acceleration records compatible with the site-dependent earthquake hazard. Likewise, large numbers of soil profiles may be used to account for the site-condition variability. The seismic microzonation methodology is proposed based on the probabilistic assessment of these factors involved in site response analysis. The second important issue in seismic microzonation procedure is the selection of microzonation parameters. The purpose being mitigation of structural damage, it is possible to adopt earthquake parameters like cumulative average velocity (CAV) or Housner intensity (HI) that was observed to have better correlation with building damage after earthquakes. A seismic microzonation procedure will be developed with respect to ground shaking intensity considering probabilistic values of the cumulative average velocity (CAV) or Housner intensity (HI).
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Safety performance functions for Two-Lane urban arterial segments
(Elsevier, 2023-11) Bartın, Bekir Oğuz; Ozbay, K.; Xu, C.; Civil Engineering; BARTIN, Bekir Oğuz
This paper presents the calibration and development process of the safety performance function for the undivided two-lane urban and suburban arterial segments in New Jersey. Data requirements, the availability of required data, and the data processing and extraction methods are presented, along with detailed results of the calibration and development process. Negative binomial, Poisson, zero-inflated Poisson and Hurdle models were generated using the development database. The best model fit was based on likelihood ratio test, AIC and BIC statistics, Vuong test and rootograms. The test database was used to calculate the calibration factor for U2 segments. The predictions of the location-specific count models were then evaluated and compared to those of calibrated Highway Safety Manual model, using the test dataset. The validation test results showed that the negative binomial and hurdle models exhibited better performance in terms of absolute residuals and absolute Pearson residual statistics. This paper also shows the impact of crash location information on analyses results, and underlines that efforts made to manually extract the missing required data can easily be offset by the inaccuracies in crash frequency databases, and the thresholds used to identify intersection related crashes.
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Estimating roadway horizontal alignment from geographic information systems data: An artificial neural network–based approach
(ASCE, 2023-11-01) Bartın, Bekir Oğuz; Jami, Mojibulrahman; Ozbay, K.; Civil Engineering; BARTIN, Bekir Oğuz; Jami, Mojibulrahman
Estimating horizontal alignment using discretized roadway data points, such as GIS maps, is complicated because the number of curved and tangent segments and their start and end points are not known a priori. This study proposes a two-step approach: The first step estimates the number and type of segments and their start and end points using an artificial neural network (ANN)-based approach. The second step estimates the segment-related attributes such as radii and length by circular curve-fitting. The novelty of this study lies in the simplicity of the input vector to the ANN model, which contains only the latitude and longitude readings of a point and those of its neighboring points. Training and test data were comprised of points extracted from curved and tangent segments of random horizontal alignments, generated synthetically using a computer programming code. The proposed approach was evaluated and compared with other available methods presented in the literature using real roadway horizontal alignment data from one freeway and one rural roadway with a total length of 47 km and 65 curved segments. The analysis results indicated that the proposed approach outperforms other approaches in terms of estimation performance, particularly when the roadway follows a winding alignment.
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Designing redundant cable-driven parallel robots for additive manufacturing using end-effector compliance index
(IEEE, 2023) Kara, Burhan; Qureshi, Muhammad Sarmad; Bundur, Zeynep Başaran; Bebek, Özkan; Civil Engineering; Mechanical Engineering; BUNDUR, Zeynep Başaran; BEBEK, Özkan; Kara, Burhan; Qureshi, Muhammad Sarmad
This paper presents a methodology for optimizing cable anchor points for cable-driven parallel robots (CDPRs) for specific additive manufacturing tasks. Much of a CDPR's workspace is generally not used for printing tasks. The unused workspace of the CDPR can be sacrificed to gain greater control to fulfill the printing task. In this paper, the CDPR is designed for a specific task to achieve the best printing results. To find the optimum robot size, the stiffness of the end-effector and mean cable tension are analyzed. The end-effector compliance index (ECI) is proposed to assess the stiffness of the end-effector within the workspace. The ECI uses cable directions to determine the compliance of a given robot pose. From simulation results, a relation to get optimum CDPR frame size is achieved for both suspended and constrained type CDPRs. The proposed method can be used to design low-cost cable-driven robots for additive manufacturing.
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A suite of broadband physics-based ground motion simulations for the Istanbul region
(Wiley, 2023-04) Zhang, W.; Crempien, J. G. F.; Kurtuluş, Aslı; Chen, P.-Y.; Arduino, P.; Taciroglu, E.; Civil Engineering; KURTULUŞ, Asli
Physics-based earthquake ground motion simulations (GMS) have acquired significant growth over the last two decades, mainly due to the explosive developments of high-performance computing techniques and resources. These techniques benefit high/medium seismicity regions such as the city of Istanbul, which presents insufficient historical ground motion data to properly estimate seismic hazard and risk. We circumvent this reality with the aid of the Texas Advanced Computing Center (TACC) facilities to perform a suite of 57 high-fidelity broadband (8–12 Hz) large-scale physics-based GMS for a region in Istanbul, Turkey. This paper focuses on the details of simulated GMS: (i) validation of the GMS approach against recorded ground motions produced by the 2019 (Formula presented.) Silivri earthquake; (ii) characteristics of 57 different source models, which aim to consider the uncertainties of many fault rupture features, including the length and width, dip, strike, and rake angles of considered fault planes, as well as hypocenter locations and earthquake magnitudes ranging between (Formula presented.) 6.5 and 7.2; (iii) high-resolution topography and bathymetry and seismic data that are incorporated into all GMS; (iv) simulation results, such as PGAs and PGVs versus (Formula presented.) and distances to fault ruptures ((Formula presented.)), of 2912 surface stations for all 57 GMS. More importantly, this research provides a massive database of displacement, velocity and acceleration time histories in all three directions over more than 20,000 stations at both surface and bedrock levels. Such site-specific high-density and -frequency simulated ground motions can notably contribute to the seismic risk assessment of this region and many other applications.
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Regional-scale seismic fragility, loss, and resilience assessment using physics-based simulated ground motions: An application to istanbul
(Wiley, 2023-05) Zhang, W.; Chen, P. Y.; Crempien, J. G. F.; Kurtuluş, Aslı; Arduino, P.; Taciroglu, E.; Civil Engineering; KURTULUŞ, Asli
Using results from 57 large-scale physics-based fault-rupture and wave propagation simulations, this research aims to evaluate the seismic risk, loss, and resilience of more than 16,000 reinforced concrete buildings in the Zeytinburnu district of Istanbul, Turkey. For each building and under each earthquake scenario, the spatially varying site-specific simulated ground motions were used for performing three-dimensional nonlinear time-history analyses. The resulting structural responses—such as peak story drift ratios (PSDR) and peak floor accelerations (PFAs)—were utilized to conduct three region-scale tasks: (i) building- and site-specific seismic fragility analysis for both structural and nonstructural components of each building; (ii) intensity-based seismic loss assessment using the FEMA P58 methodology and Monte Carlo simulations; and (iii) resilience evaluation based on the expected time of recovery predicted through FEMA P58. Moreover, both inertial and kinematic soil–structure interaction (SSI) effects were considered using a substructuring method for all three tasks. Site-specific soil properties were utilized to compute the coefficients of soil springs and dashpots, as well as the foundation input motions. The SSI effects were investigated by comparing the fragility, loss, and resilience indices obtained with and without considering SSI.
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Implementing artificial neural network-based gap acceptance models in the simulation model of a traffic circle in SUMO
(Sage, 2023-12) Bagheri, Mohammad; Bartın, Bekir Oğuz; Ozbay, K.; Civil Engineering; BARTIN, Bekir Oğuz; Bagheri, Mohammad
The impact of various operational and design alternatives at roundabouts and traffic circles can be evaluated using microscopic simulation tools. Most microscopic simulation software utilizes default underlying models for this purpose, which may not be generalized to specific facilities. Since the effectiveness of traffic operations at traffic circles and roundabouts is highly affected by the gap rejection-acceptance behavior of drivers, it is essential to accurately model drivers' gap acceptance behavior using location-specific data. The objective of this paper was to evaluate the feasibility of implementing an artificial neural network (ANN)-based gap acceptance model in SUMO, using its application programming interface. A traffic circle in New Jersey was chosen as a case study. Separate ANN models for one stop-controlled and two yield-controlled intersections were trained based on the collected ground truth data. The output of the ANN-based model was then compared with that of the SUMO model, which was calibrated by modifying the default gap acceptance parameters to match the field data. Based on the results of the analyses it was concluded that the advantage of the ANN-based model lies not only in the accuracy of the selected output variables in comparison to the observed field values, but also in the realistic vehicle crossings at the uncontrolled intersections in the simulation model.

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