http://103.99.128.19:8080/xmlui/handle/123456789/91 DEM Sun, 13 Sep 2026 04:02:06 GMT 2026-09-13T04:02:06Z http://103.99.128.19:8080/xmlui/handle/123456789/580 Title: PROBABILISTIC LIFE-CYCLE COST ASSESSMENT OF STAINLESS STEEL REINFORCED CONCRETE BRIDGE GIRDER UNDER MULTIPLE HAZARDS Authors: Islam, Tauhidul; ID:, 18MDEM009P Abstract: Reinforced concrete (RC) bridges are considered as the most important node for the transportation networks which play very crucial role in sustainable economic development of any nation. However, performance of reinforced concrete bridge with ordinary rebar under multiple hazards is found to be deteriorated severely. In order to maintain the performance of the bridge over a threshold value, regular inspection and maintenance actions are required to ensure their continuous service leading to higher lifetime cost. In addition to the increase in lifetime cost, the inspection and maintenance activities may also tremendously raise the indirect costs to the users due to traffic delays and loss of productivity. Furthermore, the inspection and maintenance activities may also hinder the continuous traffic movement over the bridge and the consequences in negative impact on environment and social life. Although, use of stainless steel rebar in constructing RC girder will increase construction cost, however, it will reduce the necessity of inspection and repair activities leading to lower lifetime cost. The higher construction cost of SS-RC bridge will be completely outweighed by incentives obtained from the lower repair and maintenance costs after a certain time referred as pay-off time (tpay-off) for stainless steel reinforcement economic viability which primarily depends on severity of airborne chloride hazard, price of SS rebar, and design service life of the bridge. The key purpose of this study is to determine tpay-off for SS rebar economic viability by determining the time required to obtain identical life cycle cost (LCC) value of SS- and CS-RC bridges. To fulfil this objective, two holistic flowcharts were developed to determine tpay-off for SS rebar cost efficiency. Furthermore, the proposed approach was illustrated using an RC bridge girder considering different coastal marine environments in 20 cities in Japan and the variation in SS price. The findings will assist transportation officials in deciding on selecting rebar type and cost of SS rebar to construct sustainable bridge with a nominal lifetime cost. Description: A Master of Science (M.Sc) Thesis in Disaster Engineering and Management (DEM) Department at Chittagong University of Engineering and Technology (CUET). Thu, 23 Jan 2025 00:00:00 GMT http://103.99.128.19:8080/xmlui/handle/123456789/580 2025-01-23T00:00:00Z http://103.99.128.19:8080/xmlui/handle/123456789/579 Title: Evaluation of Draft Dhaka Structure Plan (2016-2035) Regarding Drainage and Flood Management: A Case study on Turag River and Its Contributory Area Authors: Hoque, Shahnawaz; ID:, 14MSDEE007P Abstract: Turag river is an upper tributary of the Buriganga River and flows beside the western side of Dhaka, the capital of Bangladesh. Turag river and its flood plain plays a dominant role in flood management of Dhaka city as it assists to save Dhaka city from flooding by containing excessive flood water during inundation. From the very past, Turag and its tributaries are enriched with biodiversity and ecological resources and have provided enormous ecosystem services and functions to the society. Like other areas of Bangladesh, the settlement and livelihood pattern of people especially the farmers and fishermen community of Turag river floodplain are adjusted with the deltaic conditions of Bangladesh. But the lives and livelihood and the settlement of the local community are about to extinct now. Encroachment and pollution and of Turag river-flood plain ecosystem have damaged the socio-economic and ecological harmony of the region. Recognizing the importance of restoring the original character of Turag river, Department of Environment (DoE) of Bangladesh declared Turag river as „ecologically critical area‟ in 2009. The High court division of Bangladesh in 2019 passed an order by declaring Turag river a „living entity‟ and directed concerned authorities to save it from extinction and revive its original character. Conventional flood management strategies/ practices consider flood protection as their only goal but multiple ecosystem benefits/socio-ecological dimensions of flood management approaches are overlooked. In this context, there was an urgent need to critically evaluate the policies/proposals of Dhaka Structure plan (2016-2035) and Dhaka Detailed Area Plan (2022-2035) regarding drainage and flood management of Turag river and its contributory areas from multiple ecosystem benefit approach. This study attempted to understand the status of socio-ecological considerations of flood management approaches in the study area. This study also performed hydrologic and hydrodynamic analysis through mathematical modeling to understand the hydrologic and hydraulic process of the study area and then flood mapping analysis was done to understand the impact of development pattern on the flooding pattern of the study area. Finally, the policies/proposals of Dhaka Structure plan (2016-2035) and Dhaka Detailed Area Plan (2022-2035) regarding drainage and flood management of the study area were evaluated with the output derived from the socio-ecological, hydrologic and hydrodynamic analysis. The Dhaka Structure Plan (2016-2035), the strategic plan for Dhaka prepared by RAJUK, has been approved by the Inter-ministerial Steering Committee of government dated 20 November, 2016 but gazette notification has not yet been published by the government. So, in the title of the thesis, the term „Draft‟ before Dhaka Structure Plan (2016-2035) has been used. However, vi before publishing gazette notification of the plan, the gazette notification for the next tier of the plan, i.e. the Dhaka Detailed Area Plan (DAP, 2022-2035), a detailed or local plan prepared by RAJUK, has already been published dated 23 August, 2022 following approval of the government of Bangladesh. From the field investigation, it is observed that insecurity in land ownership/ tenure rights due to threat of forced eviction is the root cause for conversion of flood plains/agricultural lands to non-agricultural uses in the region. This study finds that the percentage of amount of main flood flow zone is almost same for flood map of study model and DAP (2022-2035). But, the connectivity network, position and alignment of main flood flow zone in flood map of the study model is different from those in flood map of DAP (2022-2035) and Dhaka Structure Plan (2016-2035). Besides this, for extreme flooding event (1988), the percentage of inundation extent in study model is different from that of the DAP (2022-2035) for different flood depths. There may be some differences because boundary condition and catchment extent of model for hydrodynamic analysis are different for study model and DAP (2022-2035) although existing DEM is same for both DAP (2022-2035) and study model. This study also finds that in the flood map of DAP (2022-2035), the main flood flow zone is not connected in some areas and the position and alignment of main flood zone have been shifted in some areas from Dhaka Structure Plan (2016-2035) and Dhaka Detailed Area Plan (2010-2015). But, both in Dhaka Structure Plan (2016-2035) and Dhaka Detailed Area Plan (2010-2015), the flow path of main flood flow zone is continuous. It is observed that the flood map in DAP (2022 2035) is prepared by hydrodynamic analysis based on the existing/latest available DEM (year 2014, updated in year 2018), but no oldest available DEM is used for analysis. As existing development pattern is unplanned and existing DEM only reflects the existing scenario, so in DAP (2022-2035), flooding pattern in main flood flow zone based on existing DEM reflected the existing unplanned development pattern which is the main reason for discontinuity and shifting of the position and alignment of the main flood flow zone from the previous plan. Disconnected and changing pattern of flood plains act against conservation of flood plains and can‟t deliver their ecosystem services and functions. So, it is high time to restore the original character of Turag river-flood plain ecosystem so that maximum benefits/values can be captured from the restored ecosystem services and functions. Description: A Master of Science (M.Sc) Thesis in Disaster Engineering and Management (DEM) Department at Chittagong University of Engineering and Technology (CUET). Wed, 18 Dec 2024 00:00:00 GMT http://103.99.128.19:8080/xmlui/handle/123456789/579 2024-12-18T00:00:00Z http://103.99.128.19:8080/xmlui/handle/123456789/563 Title: Vulnerability Assessment of Typical Residential Buildings of Chattogram City Corporation with Post Seismic Hazard Consideration Authors: Adnan, Md. Ridwan Alam Abstract: The seismic hazard map of Bangladesh shows that the northern and eastern regions of Bangladesh are particularly susceptible to seismic hazards. There is a high risk that a moderate to strong earthquake may result in widespread damage especially in the densely populated urban set up of Bangladesh. Being the second largest metropolis in Bangladesh, Chattogram has been built up to accommodate fast-growing population of Bangladesh. In this project, building data is collected by conducting Rapid Visual Screening (RVS) survey in a typical residential area of the city. Commonly used methods of RVS is used to collect general information of typical reinforced concrete buildings of the study area and an assessment of seismic vulnerability of the buildings is done with emphasis given post seismic hazard consideration as well. A comparative analysis of the results using FEMA 154, FEMA 310 and ASCE 41-13 RVS methods show that there exist significant problems of seismic vulnerability of buildings in the study area in relation to building parameters such as load path discontinuity, soft stories, weak brick joints, horizontal and vertical plan irregularities, strong beams/weak columns, diaphragm discontinuity etc. The results of FEMA 154 RVS method indicates that 35% of the buildings of the area fall below a cut-off vulnerability score of 2. With an average 49% percent of non-compliance of building vulnerability parameters of FEMA 310, an average or relative score of vulnerability score of 2.1 is calculated. The results of these two RVS methods seem to be an underestimate of the conditions of seismic vulnerability considering the poor conditions of buildings observed during the field study. When compared to the results of average 60% non-compliance of building vulnerability parameters of the ASCE 41-13 checklist, the relative score of seismic vulnerability of 1.9 better represents the observed poor conditions of buildings‟ physical conditions. According to FEMA 154, the percentage of buildings with cut-off score less than 2 is high in areas with insufficient width of roads which is indicative of the fact of narrow exit pathways or insufficient evacuation facilities during emergency situations. A few guidelines of BNBC regulations may be considered important considerations for mitigation of risks of post seismic hazards. Therefore, RVS checklists of parameters may need inclusive considerations of some additional parameters in the checklist of building vulnerability parameters such as front road width, electric and gas lines distance, built purpose and rescue facility etc. which are required to ensure earthquake resilient residential infrastructures and urban seismic resilience. Description: A Master of Science (M.Sc) Thesis in Disaster Engineering and Management (DEM) Department at Chittagong University of Engineering and Technology (CUET). Mon, 10 Mar 2025 00:00:00 GMT http://103.99.128.19:8080/xmlui/handle/123456789/563 2025-03-10T00:00:00Z http://103.99.128.19:8080/xmlui/handle/123456789/551 Title: Damage Prognosis of Aging Reinforced Concrete Structures through Visual Screening and Rebound Hammer Test Authors: Patwary, Mohammed Mahmudur Rahman Abstract: Periodic monitoring of concrete quality of Reinforced Concrete (RC) structure is essential for maintaining structural performance, ensuring regulatory compliance and continuously tracking many different causes of quality deterioration processes to ensure serviceability of aging RC structures. In this research, visual inspection of an aging RC building of Chattogram is performed according to an ACI protocol. The findings of visual screening are indicative of significant deterioration of concrete strength over the period of 40 years’ service life of the building. A non-destructive rebound hammer test (RHT) is conducted on different RC elements and results of in-situ concrete strength of the building indicates an average 13% reduction from reference strength. Current concrete compressive strengths of two other selected buildings of Chattogram are also indicative of high inconsistency between their field test results and audit records of strength. One of the major objectives of this research is, therefore, aimed at establishing reliable basis of RHT data for estimating in-situ concrete strength of RC structures. A comparative analysis of time variable strengths is performed for three laboratory scale RC beam specimens cast with two concrete strengths, 20 MPa and 22 MPa. The concrete compressive strengths determined by RHT tests of the beams is well correlated by empirical expressions of time variation of strength, and the empirical laws can be used to provide a reliable estimate of strength by 3% to 4% less than reference strengths. A selected RC structure is modelled for 3D pushover analysis considering design strength of concrete of 4 ksi and also with a randomly chosen 30% reduction of concrete strength. A comparative evaluation of their capacity curve shows that the maximum capacity of RC structure with concrete strength of 2.5 ksi is substantially low as compared to the same structure modelled with baseline strength of 4.0 ksi. The degradation of concrete strength is shown to have significantly reduced global capacity of the structure. There is also increased numbers of plastic hinges formed in the structure modeled with concrete of 2.5 ksi, particularly beyond the Collapse Prevention (CP) state of the capacity curve. A simply supported RC beam is also modelled to assess other associated effects of concrete strength degradation on crack formation and propagation. The accumulation of fracture strain and formation of cracks are more concentrated near the failure zone of the RC beam modelled with lower strength of concrete. Description: A Master of Science (M.Sc) Thesis in Disaster Engineering and Management (DEM) Department at Chittagong University of Engineering and Technology (CUET). Sun, 12 Jan 2025 00:00:00 GMT http://103.99.128.19:8080/xmlui/handle/123456789/551 2025-01-12T00:00:00Z