-
An Experimental Study of Shear Stress Distribution in a Compound Meandering Channel
Abdullah Al Amin,
S. M. Khan,
Ashraf-ul-Islam
Issue:
Volume 1, Issue 1, July 2013
Pages:
1-5
Received:
20 May 2013
Published:
10 June 2013
Abstract: Naturally river flow can be characterized as compound meandering channel in which the shear stress characteristics are quite intricate. Reliable investigation of shear stress distribution in a compound meandering channel is essential in solving a variety of river hydraulics and engineering problems, designing stable channels and bank protection, understanding the mechanism of sediment transport. A laboratory experiment has been conducted in a compound meandering channel with symmetric cross-sections having floodplain width ratio of 1, 1.67, 2.33, 3 and depth ratio of 0.20, 0.30, 0.35, 0.40 using the large-scale open air facility in the Department of Water Resources Engineering, Bangladesh University of Engineering and Technology (BUET), Dhaka, Bangladesh. Point velocity data have been collected using an ADV (Acoustic Doppler Velocity Meter) for different depth and width ratio at different locations of a compound meandering channel. Shear stress is calculated from the Prandtl-Von Karman Universal Velocity Distribution Law. The laboratory experimental investigation reveals that shear stress increases with the increase of depth and width ratio and low magnitude of boundary shear is observed in the outer bend as compare to the inner bend in a compound meandering channel.
Abstract: Naturally river flow can be characterized as compound meandering channel in which the shear stress characteristics are quite intricate. Reliable investigation of shear stress distribution in a compound meandering channel is essential in solving a variety of river hydraulics and engineering problems, designing stable channels and bank protection, un...
Show More
-
Suitability of Pre-Perforated Post-Reinforced Baked Clay Beam Panels for Low Cost Housing
Abdul Aziz Ansari,
Nadeem-ul-Karim Bhatti,
Muhammad Aslam Bhutto
Issue:
Volume 1, Issue 1, July 2013
Pages:
6-15
Abstract: Systematic research is being carried out since last more than one decade to prove the validity, method and materials for construction of locally available alternatives as low-cast systems for the sake of swift erection of buildings at relatively affordable cast of construction, where the pre-cast post-reinforced panels are used for erection of buildings without sacrificing the strength and durability of the buildings. One of the most universally available materials of construction since immemorial times is the earth itself, particularly in the plain areas (Pakistan) where the soil is fertile and the availability of best combination of clay and sand is not problematic. In this paper the authors present the details of systematic research which has been carried out to prove that if pre-perforated post-reinforced baked clay beams are employed for pre-cast construction, the economy could be achieved by up to 30 % without sacrificing strength, durability and stability of construction. Initially soil was dug from 25 sites at a depth of 4 ft. Their physical properties were determined. The presence of various salts and their proportion were also found. A very large number of cubes were cast with clay as major material and percentage of pit-sand (silica) as major parameter. The results of preliminary study in terms of shrinkage, specific gravity, crushing strength, tensile strength, poison’s ratio, and modulus of elasticity of baked clay specimen and the best possible combination of clay and pit-sand were obtained. The material was then compacted by applying compression. Fifty two beams with 70% clay and 30% pit-sand, 20 percent water and 4.5 N/mm2 compacting force were cast, dried, baked, post-reinforced, grouted with cement and hill-sand slurry with the ratio of 1:1 for proper bond between steel bars and surrounding baked clay were tested with point load, UDL and various boundary conditions including roller support, plate support and complete end-fixity. Full details are presented in the following section.
Abstract: Systematic research is being carried out since last more than one decade to prove the validity, method and materials for construction of locally available alternatives as low-cast systems for the sake of swift erection of buildings at relatively affordable cast of construction, where the pre-cast post-reinforced panels are used for erection of buil...
Show More
-
Hybrid Fibre Optic Sensor Network for Real-time High Temperature Performance Monitoring of Steel Structures
Issue:
Volume 1, Issue 1, July 2013
Pages:
16-23
Received:
22 May 2013
Published:
20 June 2013
Abstract: In and post a fire event, an accurate and real-time evaluation and monitoring of a structure’s performance can assist firefighters for efficient survivor rescuing, which significantly improve the fire rescuing safety both for fire fighters and the trapped survivors. However, due to the lack of durable sensors, the structural performance of steel structures in fire conditions is challenging to be evaluated in real time, especially when the associated civil structures are in a large scale. In this paper, a fiber optic sensor network is developed and used to monitor the structural performance of the steel structures in high temperature environments. The fiber optic sensor network has the capacity of real-time large strain measurement up to 12% and temperature of up to 700ºC simultaneously. The capability of large strain measurement up to 12% enables the sensor system to monitor the strain distribution of steel structures during fire events in real time. An one-story one-bay steel frame (A36 steel) is used as an example in this paper to perform the structural performance assessment of steel structures in high temperature using the developed sensor network. The simulated fire tests were performed using high temperature furnace through gradual temperature increase from room temperature to 800 °C at a rate of 10 °C/min. The evaluated fiber optic sensor network consists of two long period fiber grating (LPFG) temperature sensors, five movable extrinsic Fabry-Perot interferometric (EFPI) large strain sensors, and two hybrid EFPI/LPFG sensors, which were distributed along the steel frame inside and around the heating zone of the frame. Experimental results demonstrated that the developed sensor network effectively monitored the plastic hinge formation and failure mode of the steel frame, approving the feasibility of the sensor network for steel structure evaluation in high temperature environments.
Abstract: In and post a fire event, an accurate and real-time evaluation and monitoring of a structure’s performance can assist firefighters for efficient survivor rescuing, which significantly improve the fire rescuing safety both for fire fighters and the trapped survivors. However, due to the lack of durable sensors, the structural performance of steel st...
Show More
-
Assessing the Sustainability of Existing Buildings Using the Analytic Hierarchy Process
Lucio V. Rosa,
Assed N. Haddad
Issue:
Volume 1, Issue 1, July 2013
Pages:
24-30
Received:
28 May 2013
Published:
20 June 2013
Abstract: Relative concepts of sustainability are more and more influenced by societies around the world. The construction industry, especially for building construction development, is being accused of promoting environmental impacts that range from excess use of resources to pollution generation. This paper present an application of the sustainability concept applied to buildings, as well as, a contribution to the development of practices, methodology and tools for evaluation of already existing buildings. In order to achieve that, this study will detail how current systems to evaluate building performance operate, and how can we improve them. The Analytic Hierarchy Process (AHP), a multi-criteria method, is used as a tool to investigate the relative importance of the criteria, sub-criteria and families of indicators established by the researcher and interested parties, and adjust the proposed system to the local culture. AHP usage allowed a deeper insight into the problem.
Abstract: Relative concepts of sustainability are more and more influenced by societies around the world. The construction industry, especially for building construction development, is being accused of promoting environmental impacts that range from excess use of resources to pollution generation. This paper present an application of the sustainability conc...
Show More
-
Hydrodynamic Characteristics of Expanded Channels with their Applications----the State-of-the-Art
Issue:
Volume 1, Issue 1, July 2013
Pages:
31-40
Received:
21 May 2013
Published:
30 June 2013
Abstract: In this study, analytical-statistical solutions of the characteristics in gradually and abruptly expanded channel flows, such as velocity profile, turbulent shear stress profile and profiles of turbulent kinetic energy, energy dissipation rate, and dispersion coefficient are derived. Then, the comparisons of the analytical results are made with the results of 2-DH with depth-averaged numerical model solution and some experimental results.Good trends and agreements are obtained, and the expanding angletakes an important and relevant role on the main effect of these hydrodynamic items. The quasi-3D flow situation due to the downstream abruptly contracted channel with the upstream abruptly expanded channel is also shown and discussed. In this paper, the new contributions, ideas, clarifications and applications that resulted after the paper was given are presented.
Abstract: In this study, analytical-statistical solutions of the characteristics in gradually and abruptly expanded channel flows, such as velocity profile, turbulent shear stress profile and profiles of turbulent kinetic energy, energy dissipation rate, and dispersion coefficient are derived. Then, the comparisons of the analytical results are made with the...
Show More
-
Detection Spacing of DSRC-Based Data Collection System for Real-Time Highway Travel Time Estimation
Sang Cheal Byun,
Suhyeon Kim,
Min Heon Kim,
Sang Wook Han
Issue:
Volume 1, Issue 1, July 2013
Pages:
41-48
Received:
29 May 2013
Published:
30 June 2013
Abstract: A DSRC (Dedicated Short-Range Communication)-based traffic data collection system has been introduced to enhance the accuracy of real-time traffic information. However, due to the lack of studies for the DSRC system on interrupted flow condition, there is no installation guideline of DSRC RSEs on the national highways in Korea. This study presented an appropriate spacing of DSRC RSEs for the national highways based on the accuracy of traffic information and the required minimum sample size. By analyzing the field data collected on the national highways, the optimal spacing of DSRC RSEs was selected for each type of road. According to the result, the optimal spacing for controlled-access highway was different from that for multi-lane road and urban and suburban arterial. It implies that detection spacing should be determined considering the type of road. These results would be utilized as a guideline for installing DSRC RSEs on the national highways.
Abstract: A DSRC (Dedicated Short-Range Communication)-based traffic data collection system has been introduced to enhance the accuracy of real-time traffic information. However, due to the lack of studies for the DSRC system on interrupted flow condition, there is no installation guideline of DSRC RSEs on the national highways in Korea. This study presented...
Show More
