Dissertations/Theses - Department of Civil Engineering

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Author: search.filters.author.Aminul Islam, Md.Has files: Yes

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    Dynamic behaviour of unreinforced masonry building
    (Department of Civil Engineering, CE , BUET, 2018-12-17) Aminul Islam, Md.; Ahsan, Dr. Raquib
    Unreinforced masonry (URM) buildings represent a large portion of the buildings stock around the world and in Bangladesh. During the construction of those buildings very little or no seismic design requirements are considered. Recent earthquakes e.g. Gorkha earthquake in 2015 have shown that many such buildings are seismically vulnerable; therefore, the demand for dynamic analysis and upgrading strategies of these buildings has become increasingly stronger in the last few years. Moreover, no dynamic test on unreinforced masonry building made by Bangladeshi indigenous material is done yet. Therefore, the objective of this study is to understand the dynamic behavior of a typical unreinforced masonry (URM) building of Bangladesh. For this purpose, a half-scale URM room having dimension of 6' x 5' (length x width) with 5' height and 2.5'' wall thickness, were built using M2 type mortar (c:s=1:4) and half-scale brick units. Time history of Imperial Valley Earthquake was chosen as an input motion because pre-dominant frequency (5Hz) of Scaled Imperial Valley earthquake is close to the model's pre-dominent frequency (6Hz). The URM model was tested as reference specimen. Then, the reference specimen was retrofitted on all faces using 18 gauge wire mesh (12mm x 12mm (1/2'' x 1/2'') opening), which is locally available and retested again. The tests were conducted on a uni-directional earthquake simulator. The tests show that wire mesh may be used as a retrofitting material for URM buildings. The retrofitting measure decreased the specimens’ lateral deflection by a factor of 4.3 to 4.8 times compared to the reference (URM) specimen for different intensities of earthquake. In addition, the upgrading enhanced the cracking resistance and the energy dissipation of the upgraded specimen. The upgraded specimen is able to undergo 1.42 times more acceleration than reference specimen. Lateral load of the reference model is compared with the prescribed shear force (capacity) as per Bangladesh National Building Code (BNBC 1993). The reference model failed after reaching the capacity. Therefore, the code is conservative in terms of lateral load resistance capacity.
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    Assessment of rural transport accessibility in Bangladesh
    (Department of Civil Engineering, 2017-04-19) Aminul Islam, Md.; Shamsul Hoque, Dr. Md.
    ABSTRACT This research paper has been prepared to estimate rural transport accessibility index to help decision makers integrate transport interventions into poverty reduction programs and to develop the relationships between rural accessibility improvement and socio-economic parameters of Bangladesh. In order to achieve the objectives of this research, at first road transport network of Bangladesh was collected from Roads and Highways Department (RHD) and Local Government Engineering Department (LGED). The district administrative area boundary was collected from LGED. Then the demographic and socio-economic data of sixty-four (64) districts of Bangladesh was collected from Bangladesh Bureau of Statistics (BBS). The road network and administrative boundary data are in the form of GIS environment. The districts demographic statistics are in the form of tabular data. After collecting the data, the analyses were done using GIS software and Microsoft Excel Analysis Toolpack (e.g. Data Analysis Tool, Data Solver Tool). Rural Transport Accessibility was estimated by ArcGIS-ArcMap. From the analysis, rural transport accessibility index of sixty-four (64) districts of Bangladesh has been estimated considering only the paved road transport (motorable all the year round) network across the country. Then the estimated accessibility value has been compared with the poverty incidence and with other socio-economic parameters to establish a relation among them. At the bottom line, a district ranking was prepared to prioritize the budget allocation in physical infrastructure that will seek help the policy maker to foster poverty free and equitable development vision of Bangladesh. Moreover, Data Envelopment Analysis (DEA) and Correlation Analysis were carried out to establish the priority ranking setting the target to minimize the objective function (in this case poverty incidence) and to investigate the correlation (if exists any) among the accessibility to the poverty incidence and socio-economic parameters.
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    Influence of span to depth ratio on the shear strength of reinforced concrete deep beam
    (Department of Civil Engineering, 1997-12) Aminul Islam, Md.; Bosunia, Dr. M. Shamim Z.
    A total of twenty five brick aggregate reinforced concrete deep beams have been tested in this study in order to investigate the influence of span to depth ratio on the shear strength of reinforced concrete deep beam. The test beams were single span and simply supported type. The beams were divided into five series according to their span to depth ratio (LID = 1 to 5). The first beam of each series was designed and detailed as per the recommendations of ACI Building Code (ACI 318-89). In the other four beams of each series, the amount of either flexural or horizontal web reinforcement or both were changed in relation to those of first beam of the corresponding series. All the beams were tested under single concentrated loading at mid span. The effects of different web steel arrangement and span/depth ratio on cracking load, ultimate load, crack patterns and modes of failure were investigated. It was observed in the study that the amount of both flexural and horizontal web reinforcements influenced the diagonal cracking load and the ultimate load capacity of test beams to some extent. It was also found that the change in the amount of either the vertical or the horizontal web reinforcement alone could not bring a significant change in the load carrying capacity of test beams. After comparing the observed initial cracking stress with that of by de Cossio(9), Kabir(7) and Rashid(10) , it was found that the observed initial cracking stress was very close to the stress calculated by de Cossio(9). It was also observed that the shear strength capacity of the deep beam having LID ratio five was very close to the shear capacity of ordinary rectangular beam of similar size. In general the ACI 318-89 recommendations regarding the ultimate strength of deep beams were observed to be conservative. Some available formulae (e.g. ACI 318-89, Ray & Reddy and Ramkrishnan & Ananthanarayana) were used to estimate the ultimate load in shear of deep reinforced concrete beams. It was shown that all the three formulae can be used efficiently to determine the ultimate shear strength of deep beams but these formulae need some modifications as proposed by Kabir(7) and Rashid(10).