Thesis published in Dept. of C.E. http://103.99.128.19:8080/xmlui/handle/123456789/12 2026-04-19T10:37:12Z 2026-04-19T10:37:12Z Hossain, Md. Imran http://103.99.128.19:8080/xmlui/handle/123456789/459 2025-09-08T04:59:30Z 2023-09-20T00:00:00Z

Title: PERFORMANCE EVALUATION OF NDTS IN PREDICTING COMPRESSIVE STRENGTH OF CONCRETE Authors: Hossain, Md. Imran Abstract: Accurate prediction of concrete compressive strength is imperative for investigating the in-situ concrete quality. To avoid destructive testing, developing reliable predictive models for concrete compressive strength using nondestructive tests (NDTs) is an active area of research. However, many of the developed models are dependent on calibration and/or concrete past history (e.g. mixture proportion, curing history, concrete mechanical properties, etc.), which limits their utility for in-situ predictions. The main objective of the study to establish a relationship between NDT test results with the compressive strength of the structures. This study developed predictive models for concrete compressive strength. In this study, concrete cylinders were casted with strength varied from 15 to 60 MPa. Ultrasonic pulse velocity (UPV) and rebound hammer (RH) tests were performed on 90 concrete cylindrical samples and 90 concrete core cylindrical samples. After that, compressive strengths were determined using destructive testing on 90 cylinders and 90 core cylinders. The rebound number at 7 days shows the concrete quality varied from fair to good for C15 to C60 grade of Concrete for both cylinder and core cylinder. For similar grade of concretes, the rebound number at 28 and 90 days shows the concrete quality varied from good to excellent. The UPV test results show that the concrete quality varied from very good to excellent for both cylinder and core cylinder. It is found that the strength obtained from rebound hammer and core cutting is well comparable with cylinder crushing strength. RH strength is found lower than the cylinder compressive strength for all grade of concrete by an amount of about 3% to 8%. Whereas, core strength is found lower than the cylinder compressive strength by an amount of about 8% to 11% for all grade of concrete. Finally, predictive equations were developed at 7, 28 and 90 days age of concrete cylinder and concrete core based on NDT results. Description: A Master of Science thesis from the Department of Civil Engineering

2023-09-20T00:00:00Z Masum, Md. Mehedi Hassan http://103.99.128.19:8080/xmlui/handle/123456789/458 2025-09-08T04:58:36Z 2023-05-18T00:00:00Z

Title: Modeling of LIDs in Context of Sustainable Urban Drainage System Authors: Masum, Md. Mehedi Hassan Abstract: Urban cities in developing countries often suffered from water logging induced by stormwater runoff due to the underperformance of their existing drainage networks, influenced by changed land use and climate, with an inappropriate solid waste management system and the absence of wastewater networks. Although traditional drainage design is seen as accommodating runoff volume, runoff quality and drainage design amenities are often overlooked. Therefore, a drainage network constructed with conventional methods failed to address sustainability aspects that give equal importance to quantity, quality, and amenity. In this context, sustainable urban drainage systems, or low impact development (LID), open the windows of drainage design by integrating all the above aspects with cost-effectiveness. Although several studies on the quantity, quality, and amenity of drainage networks exist on separate scales, an integration of all of these along with cost-effective implementation is yet to be studied in detail. The aim of the study is to evaluate the performance of LID components, including quantity, quality, and amenity aspects, at a watershed scale under different climatic scenarios in the context of stormwater management using the Chaktai-Rajakhali watershed, which serves as significant stormwater drainage outlets for Chattogram city. The Personal Computer Storm Water Management Model (PCSWMM) software was used to simulate the rainfall-runoff and runoff quality derived from three different LID scenarios (S2-S4) addressing sources to the destination of runoff through the canal. Basic statistical analyses including principal component analysis (PCA) were performed using Statistical Package for the Social Sciences (SPSS v. 23). In addition, Sustainable Technologies Evaluation Program (STEP), a life cycle costing tool v. 3.0., has been used to evaluate the cost-effectiveness of proposed LIDs. The study revealed that the incorporation of LIDs into drainage systems can reduce peak discharge by 14% to 60% with an increase in lag time to peak flow of 30 to 105 minutes in comparison to the scenario without LID implementation. Based on runoff quality in existing or no LIDs, the event mean concentrations (EMC) of TSS, TN, TP, Zn, BOD, and COD in various land uses such as residential, industrial, commercial, and institutional were found to range from 275–1085 mg/L, 2.2–7.3 mg/L, 0.33–1.14 mg/L, 0.02-0.19 mg/L, 21–71 mg/L, and 57–201 mg/L, respectively. Moreover, the incorporation of LID techniques, while incorporating the proposed LIDs, exhibits a substantial reduction of pollutants’ amount in runoff ranging from 23 to 80%, depending on the LIDs choices. Considering the cost of installation, operation, and maintenance of proposed LIDs, it has been found that the LCA values of different LIDs vary in a wide range of 15 to 1252 US$ per square meter. While a single LID is not found to provide an effective solution (S2: vegetative swale), the S4 (combination of S2 and S4) appeared to be the most effective, followed by S2 and S3 in terms of quantity, quality, and amenity. It is hoped that the outcomes of this study can be a wakeup call to adopt sustainable urban drainage for addressing multiple benefits in future drainage design and to assist engineers, architect and city planners to manage stormwater runoff in effective ways. Description: An M.Sc Thesis of Civil Engineering Department

2023-05-18T00:00:00Z Das, Sanjoy http://103.99.128.19:8080/xmlui/handle/123456789/455 2025-09-08T04:49:14Z 2023-06-25T00:00:00Z

Title: A PARAMETRIC EVALUATION OF BURIED PIPELINE SUBJECTED TO SEISMIC EXCITATIONS Authors: Das, Sanjoy Abstract: Buried pipelines, usually carrying essential facilities, are generally known as lifeline facilities and are considered one of the most susceptible structures under seismic action. Considerable research has been conducted addressing the response of buried pipes under fault rupture and permanent ground deformation. However, research on the response of buried pipes under seismic action is seldom found in technical writings. A three-dimensional numerical analysis has been performed in this research using a FEM based software, Abaqus 6.14 to focus on the insight response of buried pipe considering potential parameters under real seismic excitation. Shell element has been used to define the pipe model, while soils have been modeled by solid elements. The interface between soil and pipeline has been modeled by penalty friction to ascertain a realistic soil-pipe interaction. The vertical time history of the 1940 El Centro Earthquake has been used for this study, and the model has been validated with an experimental study in a static case, and a similar response has been observed that implicitly justifies the accuracy of the model. The seismic response of buried ductile iron pipe under seismic excitation portrays higher displacement, and significant stress has been observed. The maximum pipe response due to seismic excitations was noticed at the mid-span along the crest line of the pipe. Accounting for the finite model, the response of pipes under different boundary conditions has been studied to clutch the overall response of pipelines under different constraints. Furthermore, a parametric study has been carried out to comprehensively examine the sensitivity of different parameters such as burial depth, and aspect ratio (D/t); embedment ratio (h/D), Soil-pipe interface friction co-efficient, pipe end-restraint conditions, soil characteristics (Dry density, Modulus of elasticity, Friction angle, Poisson’s ratio), Traffic load, operational water pressure, Unidirectional Seismic excitation on the seismic response of straight buried pipes. The observed maximum vertical spatial displacement, deformation, von Mises stress, plastic strain, etc., are graphically depicted to analyze the seismic behavior of the buried pipeline. Significant response has been noticed at shallow burial depths in the parametric analysis, and both the burial depth and boundary conditions have been found as critical parameters in the response of pipes under seismic action. The increase in embedment ratio (h/D) from 1 to 5 by up to 5 times, decreases pipe displacement, stress and strain by 28.7 %, 1.3 % and 23.2 % respectively. The maximum displacement and stress magnitude generated in thepipe increases by up to 2.87 % and 34.9 % respectively for hinge support; also, it increases by up to 2.83 % and 34.9 % respectively for fixed support with respect to roller support. The observed plastic strain in the pipe was 90.1% lower (roller); 53.1 % higher (hinge); 45.9 % higher (fixed) than the minimum elongation (10%) of DI pipe. In addition, soil properties and induced traffic load contribute substantially to the deformation of buried pipes. The maximum displacement, stress and strain developed in the pipe decreased by up to 59.2%, 84% and 100% respectively, due to an increase in soil density (from 1700 to 2160 kg/m3 by 1.27 times), the modulus of elasticity (from 19 to 96 MPa by ~5 times) of soil, the Poisson’s ratio (from 0.2 to 0.45 by 2.25 times) of soil and the friction angle (from 30º to 45º by 1.5 times) of the soil. The greatest displacement and stress values occurred in the pipe considering the traffic load (1100 kPa) on the soil significantly increased by 135.7% and dramatically increased by (1326 %) respectively compared to the no traffic load case. The observed plastic strain in the pipe due to traffic load was 90 % lower than the minimum elongation (10%) of DI pipe. Overall, numerical results demonstrate that these influencing factors can impact the seismic behaviors of the buried pipeline to different degrees and cannot be neglected in the seismic analysis. In a nutshell, this research can be used as a direction for further research to provide a comprehensive guideline for the design, safety evaluation, and protection of buried pipelines crossing seismic areas. Description: An M.Sc Thesis of Civil Engineering Department

2023-06-25T00:00:00Z Raihan, Muhammad Tanveer http://103.99.128.19:8080/xmlui/handle/123456789/454 2025-09-08T04:48:04Z 2023-06-25T00:00:00Z

Title: Properties of Roller Compacted Concrete (RCC) using Steel Slag (SS) Aggregate Authors: Raihan, Muhammad Tanveer Abstract: The selection of construction material for a specific application primarily depends on its ability to withstand the applied load. Roller Compacted Concrete (RCC), typically used for pavement construction, is a stiff, zero-slump concrete placed and compacted carefully using a vibratory roller. Its prime advantages include high construction speed, low cost, and better performance with minimum maintenance. The concept of sustainable construction materials always guides us to reduce the pressure on natural resources and optimized the use of construction materials. Steel slag (SS) is a byproduct produced during steel purification from scrap materials. This study incorporated SS in RCC production to reduce stockpiling and improve sustainability in the construction sector by using a byproduct/waste material replacing natural aggregates. The experimental works include the evaluation of the physical, chemical & mechanical properties of steel slag aggregate. Initially, Vebe consistency and then compressive, tensile and flexure strength characteristics of RCC incorporating different compositions (viz. 10%, 20%, 30%, 40%, and 50%) of SS was evaluated. From the soil compaction approach, the mix proportion was determined using the obtained optimum moisture content and maximum dry density of the mixture. Two different strength class samples were prepared with different cement content viz. 13% and 14%. The results were compared with the strength characteristics of RCC prepared with natural (control) and SS aggregates. The experimental results showed that up to 30% replacement of SS gives results compared to conventional RCC with natural aggregate. Furthermore, with this replacement rate, there is no need to trade off strength for economic gains. Description: An Master of Engineering Thesis of Civil Engineering Department

2023-06-25T00:00:00Z