Published online on September 2019
Peyman Beiranvand, Mohammad Hossein Naseri fard, Hamid Reza Ashrafi, Majid Pouraminian
Abstract: Concrete encased steel composite columns have been extensively used in construction owing to that they utilize the most favorable properties of both of constituent materials, ductility, large energy-absorption capacity, and good structural fire behavior. This paper presents a nonlinear 3-D finite element by numerical simulations using ABAQUS software model for eccentrically loaded concrete encased steel composite columns .The model accounted for the interface between the steel section and concrete. It different column dimensions, different structural steel sizes, different concrete strengths, and different structural steel yield stresses by columns with were investigated in a this study.
International Journal of Bridge Engineering, Vol. 7, No. 2, 2019: pp. 1-14
Theodore G. Konstantakopoulos
Abstract: This paper leads with the phenomenon of the bouncing of a vehicle due to an irregularity being on a road or on a bridge-deck. Attention is focused on the determination of the critical velocity for which the vehicle loses touch with the road’s or the bridge-deck’s surface following a missile’s orbit and then striking on the road or the bridge during landing. If the vehicle moves with a velocity greater than the above critical one, we determine the corresponding time (and thus the point of the bridge) at which touch is lost. Afterwards, we determine also the landing point of the vehicle.
International Journal of Bridge Engineering, Vol. 7, No. 2, 2019: pp. 15-29
Ali Moeini-Korbekandi, Alireza Ghari-Ghoran, Hamidreza Heydari-Noughabi
Abstract: Sudden changing in the track vertical stiffness along the railway track increases the dynamic loads in this place. Culverts and bridges are one of the places that railway track stiffness changes suddenly. Sudden and uneven changing of vertical stiffness between the culverts and tracks increases dynamic load, asymmetric deformations, failure of the track components and maintenance costs. One of the methods to solve the above problems is to build an approach slab in the adjacency of culverts and bridges. In the present study, the behavior of railway track adjacent to culverts with approach slab has been evaluated according to different supporting conditions (weak and rigid subgrades). For this purpose, a 3D finite element model of railway track and culvert with approach slab is built, and then different sensitivities on the geometric dimensions of approach slab (including thickness, length and slope) are analyzed. Results show that the most appropriate railway track behavior in different subgrades occurs with the construction an approach slab with the length of 4m, the thickness of 30cm and the slope of 2.5%. Finally, based on static analysis, a proper slab in the adjacency of culverts decreases rail and ballast vertical displacement about 18% and 24% respectively and based on dynamic analysis, dynamic stress in the subgrade layer, dynamic vertical displacement of the rail and the ballast and vertical acceleration of the rail decrease 48%, 23% ,22% and 25% respectively. Also the performance of slab in the weak subgrade is better than to the rigid subgrade.
International Journal of Bridge Engineering, Vol. 7, No. 2, 2019: pp. 31-52
Ali Vatanshenas, Arian Aghelfard, Davood Sharif Bajestany, Behnam Tavakoli Moghadam
Abstract: In this study the performance of two box girder bridges under near-field earthquakes was investigated. Lateral responses of two continuous span bridges were compared under two cases: with lead rubber bearings (LRB) and with rigid connections between the superstructure and substructure. Lead rubber bearings are one of the most popular seismic isolators which are used in a variety of structures such as buildings and bridges. Fifteen isolators were installed under the deck of the isolated bridge. It was observed that the superstructure received less acceleration when the bridge was equipped with lead rubber bearing isolators. There was a significant difference between the isolated and non-isolated structures in terms of base shear force and the isolated bridge showed better performance under near-filed earthquakes. This suitable performance of the isolated structure was due to the proper hysteric behavior of the lead rubber bearings.
International Journal of Bridge Engineering, Vol. 7, No. 2, 2019: pp. 53-64