181 research outputs found
Experimental investigation of effective modulus of elasticity and shear modulus of brick masonry wall under lateral load
No full textThe primary objective of this research program was to investigate the effective modulus of elasticity and shear modulus of brick masonry walls under lateral load, and to to justify using the Jaeger and Mufti method to calculate the effective modulus of elasticity and shear modulus of brick masonry walls. The experimental program involved the testing of three unreinforced brick masonry walls under in-plane and vertical loads. Linear Variable Differential Transducers were used to record the horizontal and vertical displacements of the walls. The experimental results were used to evaluate the modulus of elasticity and the shear modulus of walls under flexure. The experimental results were compared to the finite element analysis results. It was found that the finite element analysis yields similar results to the experimental results. It was also found that the Jaeger and Mufti method to calculate effective modulus of elasticity and shear modulus of brick masonry walls is effective for design purposes.May 201
Financial Development, Economic Growth, and Poverty Reduction
No full textThe frequent failure of financial liberalisation efforts in developing countries, and the serious damage which recent financial crises have imposed on these economies, have led to renewed attempts to understand the relationships between financial sector development, economic growth and poverty reduction, and to provide a more robust intellectual foundation on which to design efficient and pro-poor financial sector policies for developing countries. The paper examines the contribution that financial sector development can make to poverty reduction in developing countries. The linkages between financial and economic growth, and between economic growth and poverty reduction, are considered, and some preliminary empirical evidence is presented on these linkages. The paper goes on to argue that financial market imperfections are a key constraint on pro-poor growth, and that public policy directed at the correction of these financial market failures is needed to ensure that financial development contributes effectively to growth and poverty reduction. The final part of the paper examines in some detail the role of financial regulation and supervision policy as a key area for public intervention directed at enhancing the financial sector’s contribution to poverty reduction.
Dynamic monitoring of a prestressed concrete girder by mean of fibre optic bragg grating sensors
No full textRational analysis of empirically designed bridge decks using PUNCHED
No full textReinforced concrete bridge deck slabs make up a significant portion of bridges worldwide and are designed to efficiently withstand traffic loads. The empirical design method, specified in the Canadian Highway Bridge Design Code (CHBDC), uses the inherent arching action in these slabs to provide strength and durability. The PUNCH program was developed to analyze externally restrained steel-free bridge deck slabs, but it cannot analyze directly deck slabs with embedded reinforcement.
This research focuses on modifying the PUNCH program to enable the analysis of internally reinforced deck slabs by introducing the concept of equivalent diameter for embedded reinforcement. The study investigates how the axial stiffness of steel-concrete composites changes under varying loads and integrates these findings into the modified program, PUNCHED. The enhanced program accounts for equivalent diameters to accurately model reinforced concrete deck slabs under different loading conditions. Validation using experimental data from multiple studies confirms that PUNCHED reliably predicts both load-deflection behavior and ultimate failure loads.
The findings demonstrate that the modified PUNCHED program provides a dependable tool for engineers to evaluate the performance of reinforced concrete deck slabs. By bridging the gap between empirical design and analytical modeling, this research contributes to more precise and effective analysis of bridge deck slabs.The project was funded by Research Manitoba
Identifier: Innovation Proof-of-Concept Grant
Project title: Developing software based on the empirical evidence to rationalise design provisions of the Canadian
Highway Bridge Design Code (CHBDC) of reinforced concrete deck slab
project number 5275
CharleenOctober 202
Options for enhancing network-wide annual average daily truck volume estimates
No full textThis research presents two projects that investigate options for enhancing network-wide annual average daily truck traffic volume estimates. Annual average daily traffic (AADT) and annual average daily truck traffic (AADTT) are valuable traffic statistics that are required for safety, planning, operation, design, and environmental applications. However, it is challenging to obtain estimates of AADT and AADTT across Canada’s vast highway network due to resource limitations. It is even more difficult to obtain annual average estimates of traffic volumes by specific classes of trucks, which are used for applications such as mechanistic-empirical pavement design, bridge evaluation, and asset management.
The first research project investigates how annual average daily truck volumes can be enhanced by improving traffic count sampling strategies and technologies. To help determine the count duration needed to obtain a sufficient sample of vehicle volumes by class, the study uses continuous classification count data to simulate short-duration counts of 1 to 8 days. The change in the variability of the simulated count volumes with duration was used as an indicator of the accuracy of the AADTT estimates they would produce. The results showed that at most sites, a 7-day count of trucks could reach the same level of variability as a 1-day count of total traffic. In terms of reductions in count variability, there tended to be diminishing returns beyond a 2-day or 3-day count of total traffic and beyond a 6-day count of truck traffic.
The second research project assesses the use of commercially available probe-based data products for truck volume estimation. The study evaluates the accuracy of total traffic and truck traffic estimates obtained from the third-party data provider StreetLight Data by comparing them to volume estimates from conventional traffic counts. This work contributes new knowledge by being the first evaluation of StreetLight Data’s medium-duty and heavy-duty truck indices in North America. The findings indicated that the probe-based AADT and heavy-duty AADTT estimates had the highest and lowest accuracy, respectively. Further, it was found that probe-based AADT and AADTT estimates were reasonably similar to the estimates obtained from short-duration counts with mean absolute percent differences of approximately 25%.National Research Council Canada, International Road Dynamics, Inc., Institute of Transportation Engineers Canada, Transportation Association of Canada, Canadian Transportation Research ForumOctober 202
Rationalization of the empirical design method for reinforced bridge deck slab
No full textAbstract
The empirical design of reinforced concrete bridge deck slabs of girder bridges, referred to as only ‘deck slabs,’ is the most efficient design method because it recognizes the inherent arching action that exists in these slabs. Because of the arching action, the deck slabs fail in a punching shear mode under much higher wheel loads than the loads that would make them fail in bending; it is noted that failure in bending assumes the absence of the arching action. The Canadian Highway Bridge Design Code provides specifications for the empirical design of deck slabs. As the term ‘empirical design’ implies, this method is based on experimental evidence rather than analytical methods. A computer program, PUNCH, based on an analytical method, was developed to analyze the failure loads of externally restrained deck slabs, also referred to as ‘steel-free deck slabs,’ which do not contain embedded reinforcement for strength. In this program, it is assumed that the transverse confinement to deck slabs is provided by steel straps lying outside the deck slabs. Thus, this program only models the behavior of externally reinforced bridge deck slabs accurately.
For internally reinforced bridge deck slabs, the stress-deformation behavior of steel in concrete is investigated in experimental evidence on concrete prisms, each with an embedded central steel bar, which has confirmed that when these prisms are subjected to tensile forces through the steel bars, the axial stiffness of the composite prisms is initially much larger than that of the bare steel bar, and decreases nonlinearly with the increase in the magnitude of tensile force. A reinforced concrete prism can thus be conceptually replaced by a hypothetical equivalent steel bar, the diameter of which is larger than that of the bare steel bar and decreases with the increase in the magnitude of the tensile force.
This thesis attempts to modify the program PUNCH to analyze deck slabs with embedded steel bars by replacing the bars with hypothetical equivalent steel bars that lie outside the concrete.
The first part of the research work involves the establishment of the changing equivalent diameter of the composite concrete prisms under gradually increasing tensile forces. This research was conducted through non-linear finite element analysis, the results of which were compared favorably with available experimental results.
The second part of the research was first to modify the PUNCH program to include variable axial stiffness of the external restraint and then to use the modified program to analyze a large number of deck slabs with variable external stiffness represented by hypothetical steel bars of varying equivalent diameters. The accuracy of the results has been established by comparing its results with those from available experimental tests, some of which were failure tests. Predictions from the modified PUNCH have confirmed that most reinforced concrete deck slabs never fail under wheel loads of even the heaviest commercial trucks traveling on highways. The modified PUNCH program is now called PUNCH.ED, can be used with confidence for predicting not only the failure loads of deck slabs but also their load-deflection behavior under smaller; loads.October 202
- …
