Revista de Ingeniería Civil y Ambiental

Navigation lock is a structure in the waterway provided to create a safe navigation passage between two water pools which are not at the same level. The reason for difference in water levels can be natural such as tidal variations or can be manmade such as construction of dam or barrage across the river. The main components of Navigation lock comprise of approach channels, lock pit, filling/emptying arrangement. Design of lock depends on lockage time, water level variations, Lock capacity requirements, design vessel size. filling/emptying system shall be designed to work under gravity flow without any pumping requirements. Filling/emptying system is chosen to get appropriate filling/ emptying time. The optimum time for filling and emptying is generally kept between 8.0-10.0 minutes. The size of filling culverts are so computed to attain the optimum time for filling/emptying. Every lock is unique in terms of its geology, location, size, requirements and water level differences. Here typical design aspects of a navigational Lock in inland waterway have been described.

In this study the biodegradation of five biocides such as Isoproturon (IP), Octyl-isothiazolinone (OIT), Terbutryn (TB), Cybutryne, Irgarol (IRG) and Tebuconazole (TBU) in raw wastewater have been investigated. The laboratory experiment was performed under three conditions as aerobic, anaerobic and aerobic with substrate (molasses). The biocides concentration was detected using High Pressure Liquid Chromatography coupled with Mass Spectrometer (HPLC-MS). This was conducted to quantify the biodegradation of biocides in wastewater. Under these three conditions investigated Isoproturon (IP) had no clear degradation. Octyl-isothiazolinone (OIT) is significantly biodegraded in all three conditions. Terbutryn (TB), Cybutryne, Irgarol (IRG) and Tebuconazole (TBU), investigated are slowly biodegradable. From the experiment, it is observed that aerobic with substrate condition is most suitable for biodegradation of the selected biocides.

The use of fiber-reinforced polymer (FRP) as a reinforcing agent in concrete structures has created an increased interest in recent years. However, the behavior of such members in fire is still relatively unknown. This is the main reason limiting the widespread use of FRP in buildings. A reliable model is needed to aid designers towards the prediction of failure time of FRP reinforced concrete structures exposed to fire based on the service moment. Therefore, the main of goal of this paper is to develop a model that can predict the failure time of FRP reinforced concrete structures exposed to fire based on the moment capacity. American Concrete Institute (ACI) design codes designated for the flexural and shear strength of reinforced concrete were used as a basis for creating this model. Failure time of FRP reinforced structure under fire was obtained from literature. The moment capacity of the literature structure was calculated and was used to predict the failure time using our model. It was found that our model predicted the failure time within 20% of the time obtained from literature.

Twelve simply-supported steel fiber reinforced concrete (SFRC) wide beams without conventional stirrups were tested to investigate their shear behavior. The flexure mode of failure was secured for all of the specimens to allow for shear mode of failure. The variables were fiber volumetric ratio, concrete compressive strength, longitudinal reinforcement ratio and shear span-to-depth ratio. Eight tested beams were steel fiber reinforced concrete wide beams and four beams were reinforced concrete wide beams without steel fiber for comparison purposes. End-hooked steel fibers of volumetric ratio ranging from 0% to 1.25% were used in the specimens. All beams were tested under four-point loading to investigate their behavior in shear, cracking pattern, ultimate capacity and ductility. Test results showed that the shear cracking, the ultimate shear strength and ductility increased with increasing fiber volumetric ratio, decreasing shear span to depth ratio, increasing concrete compressive strength and increasing longitudinal reinforcement ratio. The using of a dose of 0.75% fiber content in the wide beams without shear stirrups was adequate to achieve the ultimate resistance that is the same as the conventional RC wide beam with conventional stirrups. Evaluation of the ultimate shear strength of the SFRC wide beams based on previous models is presented.

It is vital that Bangladesh decouples its economy from the harmful environmental outcomes of the economic growth pathway it is pursuing currently. So it is significant that green growth is pursued with the aim of unlocking Bangladesh from its unsustainable development pathway to more sustainable as well as an inclusive one through the application of strategic environmental assessment (SEA). The article seeks to emphasize the role of SEAs could play in supporting the green growth in Bangladesh. The paper addresses the environmental assessment and overview of SEA in Bangladesh. It explores the enabling factors for SEA and challenges of SEA. The empirical basis for the paper, has drawn on experiences gained from a recent practice of SEA to support green growth in different sector of different country. With the aim of the green growth, promote the use of SEA in the national and sector development plans and strategies, as well as in decisions and actions relating to environmental goods and services. Bangladesh as an effective environmental assessment system with the application of SEA is still faraway reaching but through increasing awareness, learning and research, donor pressure and proper initiative by government it is achievable.