An approach for failure analysis of composite bridge deck systems with openings

Zhao, Lei,Karbhari, Vistasp M. Techno-Press 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.20 No.1

Design details pertaining to the connection between some recently developed fiber reinforced polymer (FRP) composite deck systems and the supporting girders require openings through cells of the deck. This significantly changes the stress distribution in these components. As a result, the conventional assumptions that deck designs are controlled by their stiffness, and not strength, needs a closer examination. This paper proposes an analytical method to investigate the stress states and failure mechanisms using a type of "global-local" modeling perspective, incorporating classical lamination theory and first ply failure criterion with use of appropriate stress concentration factors around the cutouts. The use of a "smeared-stress" approach is presented as a potential means of simplifying certain FRP specific complexities, while still enabling prediction of overall failure.

Tensile response of steel/CFRP adhesive bonds for the rehabilitation of civil structures

Matta, F.,Karbhari, Vistasp M.,Vitaliani, Renato Techno-Press 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.20 No.5

There is a growing need for the development and implementation of new methods for the rapid and cost-effective rehabilitation of deteriorating steel structural components to offset the drawbacks related to welding and/or bolting in the field. Carbon fiber reinforced polymer (CFRP) composites provide a potential alternative as externally bonded patches for strengthening and repair of metallic structural members for building and bridge systems. This paper describes results of an investigation of tensile and fatigue response of steel/CFRP joints simulating scenarios of strengthening and crack-patching. It is shown that appropriately designed schemes, even when fabricated with levels of inaccuracy as could be expected in the field, can provide significant strain relief and load transfer capability. A simplified elasto-plastic closed form solution for stress analysis is presented, and validated experimentally. It is shown that the bond development length remains constant in the linear range, whereas it increases as the adhesive is deformed plastically. Fatigue resistance is shown to be at least comparable with the requirements for welded cover plates without attendant decreases in stiffness and strength.

Design approach for a FRP structural formwork based steel-free modular bridge system

Cheng, Lijuan,Karbhari, Vistasp M. Techno-Press 2006 Structural Engineering and Mechanics, An Int'l Jou Vol.24 No.5

The paper presents results of parametric studies, and an overall approach for the design of a modular bridge system which incorporates a steel-reinforcement free concrete slab cast on top of carbon FRP stiffened deck panels which act as both structural formwork and flexural reinforcement, spanning between hollow box type FRP girders. Results of the parametric studies are highlighted to elucidate important relationships between critical configurational parameters and empirical equations based on numerical studies are presented. Results are discussed at the level of the individual deck and girder components, and as a slab-on-girder bridge system. An overall design methodology for the components and bridge system including critical performance checks is also presented.

Tensile response of steel/CFRP adhesive bonds for the rehabilitation of civil structures

F. Matta,Vistasp M. Karbhari,Renato Vitaliani? 국제구조공학회 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.20 No.5

An approach for failure analysis of composite bridge deck systems with openings

Lei Zhao,Vistasp M. Karbhari 국제구조공학회 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.20 No.1

Design details pertaining to the connection between some recently developed fiber reinforced polymer (FRP) composite deck systems and the supporting girders require openings through cells of the deck. This significantly changes the stress distribution in these components. As a result, the conventional assumptions that deck designs are controlled by their stiffness, and not strength, needs a closer examination. This paper proposes an analytical method to investigate the stress states and failure mechanisms using a type of “global-local” modeling perspective, incorporating classical lamination theory and first ply failure criterion with use of appropriate stress concentration factors around the cutouts. The use of a “smeared-stress” approach is presented as a potential means of simplifying certain FRP specific complexities, while still enabling prediction of overall failure.

Adaptation of New Institutional Theory in Shariah Governance Practice, Structure and Process

Md. Kausar ALAM,Yusuf KARBHARI,Md. Mizanur RAHMAN 한국유통과학회 2021 Asian Journal of Business Environment (AJBE) Vol.11 No.1

Purpose: The study aims to delineate Shariah Governance Framework (SGF) by applying the components of New Institutional Theory (NIT) to provide an understanding of how Islamic banks theoretically influence Shariah Governance (SG) practice, structure, and process. Design/methodology/approach: As it is a conceptual paper, this paper has prepared based on an analytical approach to show how such institutions could provide a more effective system concerning the contents, procedures, and practices for the multiple users in the SG process of Islamic banks. Findings: The paper critically explores the adoption of NIT to develop SGF with its existing practice, structure, and procedure. Utilizing NIT, a proposed theoretical framework has developed for exploring the SG through its major components, i.e., 'isomorphism' and 'legitimacy'. It is stated that NIT can offer a useful framework by which homogenous structures, comprising guidelines, standards, and practices become recognized and authorized as a satisfactory standard corporate exercise. Thus, the proposed theoretical framework would be beneficial in understanding and exploring the SGF. Conclusion: The application of this SGF could help to justify the key dimensions of NIT with its overall formation, function, and practices that might also help to attain legitimacy.

Macroeconomics Factors That Discriminate Sovereign Rating Changes

( Soh Wei Chee ),( Cheng Fan Fah ),( Annuar Nasir ),( Yusuf Karbhari ) 한국EU학회 2019 Asia-Pacific Journal of EU Studies Vol.17 No.2

The objective of this study is to determine the link between economics factors and sovereign rating changes. The economic factors are expected to significantly affect the sovereign rating and hence the rating changes. The history of sovereign credit crisis has proven that it was detrimental and costly to one country and transmits to global economy through the globalized financial markets. The falling sovereign rating of the PIIGS- Portugal, Italy, Ireland, Greece and Spain slowdown the economic growth of Euro zone. In worst case of sovereign debt crisis, the debt would be defaulted which will be the last thing to be expected by the investors because the debt default will cause the international capital flight as the investors will divest their capital away. The currency system will collapse; local currency of a country will depreciate sharply with hiking inflation that will course the country to suffer from high cost of living and rising unemployment. The research question is how macroeconomics factors affect the rating changes. Due to the latest events happening in the world economy; the information on sovereign rating changes was now sufficiently available. This study used discriminant analysis for all sovereign changes from 2000 to 2012 (12 years) from 53 countries, where no study has been done. The results identified two macroeconomics factors that discriminate the upgrade and downgrade of the sovereign rating changes. The two discriminate factors are External debt/GDP and the foreign reserves/GDP. External debt/GDP indicate the percentage of debt over the amount of GDP held by one country. This factor represents the long run solvency of one country by taking GDP per capita as the measurement of income. Hence, the smaller the ratio, the more capable a country is in paying the medium or long-term debt. The Foreign reserves/GDP is the foreign currency deposit and bond held by the central bank with obligation of currency stability. This factor is the percentage of foreign reserve over GDP. These findings are plausible as both measured the health of the financial system for a country.