Published online on May 2019
Imad-Eldin Mahmoud Mahdi, Osama Mohammed Elmardi Suleiman Khayal
Abstract: In this study, the effects of both lamination scheme and boundary conditions on the natural frequencies of free vibration of laminated composite beams were investigated. The problem is analyzed and solved using the energy approach which is formulated by a finite element model. Lamination schemes for symmetric and non-symmetric laminated beams were studied. Six boundary conditions are considered; clamped _free (CF), hinged _hinged (HH), clamped _clamped (CC), hinged _clamped (HC), hinged _free (HF), free _free (FF). Each beam has either movable ends or immovable ends. It is found that both symmetrically and anti-symmetrically laminated beams of similar size and end conditions have equal natural frequencies which, generally, decrease as the angle of orientation increases. Also, It is found that the more constrained beams have the higher values of natural frequencies of transverse vibration. However, the free-free and hinged-free beams are found to have the highest frequencies of transverse vibration amongst all beams although they look less constrained. This behavior is due to the fact that the first mode of the two beams is equal zero (rigid body motion), and replaced by the second mode to be the fundamental mode. The values of the natural frequencies of longitudinal modes are found to be the same for all beams with movable ends since they are generated by longitudinal movements only. But for immovable ends, the clamped-free and hinged-free beams have equal frequencies in longitudinal vibration, and those of the other beams are also the same.
International Journal of Bridge Engineering, Vol. 7, No. 1, 2019: pp. 01-12
Bishal Bhusal, Khet Raj Dahal, Rajendra Raj Sharma, Krishna Raj Adhikari
Abstract: The aim of this study was to find out the quality of bridges using non-destructive tests. The study was conducted during the period from December 2017 to February 2018. Intensive literature survey was the technique of this study. There are several techniques to monitor the structure of bridges like condition assessment through visual inspection along with non-destructive test (NDT). This paper focuses on condition assessment along with standard testing procedure of NDT. It also describes the sequence of operation for obtaining accuracy as well as the problem associated during the test. The study found that the bridges are not so safe due to various problems such as presence of black cotton soil, scouring of the sand in the bridge pier, problem in expansion joints like wear and tear, in bearing like rusting, in Parapet wall like hitting by vehicles, minor and moderate cracks due to degrade in quality of concrete, and default designs.
International Journal of Bridge Engineering, Vol. 7, No. 1, 2019: pp. 13-24
Justin Johnson, R.K.Tripathi
Abstract: AASHTO LRFD is a standard for design of bridge structures, which has been used by many countries due to its rational results. IRC 112-2011 is a recently launched standard for the design of concrete bridge structures based on the limit state approach. By designing a deck slab with both the standards, a comparison can be drawn on the basis of strength and economy of the section. This study intends to compare the design capacity of the slab deck using IRC 112-2011 and AASHTO LRFD. In this study a two lane deck slab of 8.7m wide has been considered. The analysis has been done in STAAD Beava software. It has been concluded that the section designed with AASHTO LRFD will have more strength than with IRC 112-2011.
International Journal of Bridge Engineering, Vol. 7, No. 1, 2019: pp. 25-32
Raghav Sundria, R.K.Tripathi
Abstract: Reinforced concrete slab bridge is a common choice for small span bridge. In order to provide greater speed and more safety for present day traffic requirement highways should be as straight as possible. This requirement, along with other requirement for fixing alignment of bridge is mainly responsible of provision of skew bridges. The effect of a skew angle on simple-span reinforced concrete bridges is presented in this paper using the finite-element method. In this paper different span bridges having different width and skewness are studied. For comparison 96 bridge slab models are prepared and their response have been calculated for class A vehicular loadings according to IRC-6: 2014. Maximum value of longitudinal moment, Transverse Moment. Torsional Moment and shear forces of skew bridge are compared with straight bridge of that span. It has been found from this study that maximum longitudinal moment decreases as skewness increase while maximum transverse moment increase as skewness increases for any span. Maximum torsional moment and shear force always increase as skewness of bridge increases.
International Journal of Bridge Engineering, Vol. 7, No. 1, 2019: pp. 33-40