Published online on May 2018
Prof. Raftoyiannis, Assistant Editor of the International Journal of Bridge Engineering suffered, while teaching, a severe stroke, which eventually, after a period of two months, cut the thread of his life, in his early fifties. Ioannis Raftoyiannis obtained his Diploma in Civil Engineering from the National Technical University of Athens (NTUA) in 1987, the MSc in 1991 and his PhD from the University of West Virginia of USA on the Stability of Structures, Composite Materials and Computational Mechanics. In 2003 he was elected Assistant Professor, in 2007 Associate and in 2013 Deputy Professor of the School of Civil Engineering of NTUA. As a member of the staff of the School taught several courses on the subjects of Steel Structures, Steel Bridges, Light Metal Structures, Composite Materials and Static and Dynamic Stability of Structures. He published over 100 papers in journals and conference proceedings. He has received more 350 citations according to the Scopus database. Ioannis Raftoyiannis was a true Scholar with a gentle and peaceful character. He will be missed a great deal by the so many friends, colleagues, and students.
A. Abisheik, R. Sathyanarayan Sridhar
Abstract: This paper performs the static analysis which is commonly known as Pushover analysis. This had been used for seismic analysis of high-rise buildings to determine ultimate load and deflection capability of structure. Particularly in bridges the seismic analysis is carried out by using nonlinear dynamic analysis and nonlinear static analysis. Under nonlinear static analysis Capacity spectrum method and N2 method has been used widely for the high-rise buildings. The main aim of the paper is to imply the concepts of Capacity spectrum method and N2 method of seismic analysis in T-beam Bridge. This is achieved by modelling, analysing the T-beam Bridge in CSiBridge and SAP2000 software and comparing the output from both the software and verify the concepts of analysis with the code provision.
International Journal of Bridge Engineering, Vol. 6, No. 1, 2018: pp. 01-07
Shiraz Shahid, Irshad Ahmad, Muhammad Adeel Arshad
Abstract: Bridges in Pakistan are mostly designed to the local Class A loading having eight axles; weighing 543kN; and 18.9m in length. The objective of this research is to check the adequacy of Class A loading, as permissible axle loads are quite high locally. Numerous moving load analyses were conducted for simple spans from 6m to 50m. Calculations were performed for single and two-lane loaded bridges. Results were tabulated by comparing the maximum effects due to legal trucks with those of Class A loading. The results raised a concern as they revealed the inadequacies of Class A loading. For a single vehicle per lane, the critical case was of the shorter spans where bending moment and shear of legal trucks were 24% and 16% higher than Class A loading, respectively. With multiple vehicles per lane the results further deteriorated for Class A loading. The critical case was of the longer spans where both bending moment and shear of legal trucks were 58% and 55% higher than Class A loading, respectively. It was concluded that Class A loading is not representative of the domestic truck loading, legally operational over the highway bridges of Pakistan. Based on the permissible axle loads, a vehicular live load model for Pakistan is proposed.
International Journal of Bridge Engineering, Vol. 6, No. 1, 2018: pp. 09-22
C.C. Spyrakos, I.G. Raftoyiannis, Ch. Mouzakis
Abstract: Heavy traffic road bridges in Greece are mostly designed to the 60/30 class loading – DIN1072 with two three-axle trucks weighing 60t and 30t and 6.0m in length each. The objective of this research is to assess the adequacy of an existing multi-spam concrete bridge for tram passage where the axle loads are quite high locally. Numerical analysis is conducted for three representative single spans. Results are tabulated by comparing the maximum effects due to the tram loading with those of 60/30 class loading. The results raised a concern as they revealed some inadequacies of the load model 1 of Eurocode 1 part 2 and the tram in comparison with 60/30 class loading. Extensive field measurements and laboratory testing, as well as analytical work is performed to assess the condition of the superstructure and propose a strengthening scheme.
International Journal of Bridge Engineering, Vol. 6, No. 1, 2018: pp. 23-34
Cameron Takemori, Jeffrey A. Laman
Abstract:In many parts of the world, rural communities are separated from basic needs by streams, rivers and frequently flooded pedestrian routes. Low cost and lightweight, pedestrian suspension bridges are a solution to provide a safe travel route. Pedestrian suspension bridges are typically low mass, low stiffness, and marginally damped, resulting in the structure being susceptible to a significant dynamic response to pedestrian loading. Pedestrians often walk at a pace corresponding to suspension bridge modal frequencies, causing bridge resonance and pedestrian discomfort and unease due to the high accelerations, velocities, and displacements. A pedestrian suspension bridge possesses several modal frequencies in the vertical plane, the lateral plane, and combinations of the two. The present parametric study was completed utilizing numerical simulations to determine the dynamic response of selected pedestrian suspension bridges focusing on the influence of tuned mass dampers on the dynamic response. Four geometries and three mass ratios of tuned mass dampers were evaluated for effectiveness. The present study determined that: 1) lateral tuned mass dampers control the vertical dynamic response more effectively than vertical dampers; and 2) vertical dampers control the lateral dynamic response more effectively than lateral dampers.
International Journal of Bridge Engineering, Vol. 6, No. 1, 2018: pp. 35-62
Imad-Eldin Mahmoud Mahdi, Osama Mohammed Elmardi Suleiman
Abstract: In this study, the effect of the end conditions of cross-ply laminated composite deck beams (CLCB) on their non-dimensional natural frequencies of free vibration was investigated. The problem is analyzed and solved using the energy approach which is formulated by a finite element model. In that model, a three-noded element with three degrees of freedom at each node is assumed. Numerical results were verified by comparisons with other relevant works. The end conditions of beams are: 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 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. 6, No. 1, 2018: pp. 63-72
Abstract:This paper presents the planned design for a new steel road bridge in the Tenagi valley, Kavala, Greece. The plans are for a single span steel truss trough bridge with a span of 67 m over an irrigation channel. The new bridge will replace an existing reinforced concrete one that is no longer in service due to excessive rotation of its single pier and deck failure. The major challenge associated with the design of the new bridge is the poor soil characteristics in the region. The soil is composed of peat to a depth of over 200 m. Optimization of the type, shape, and size of the bridge superstructure is critical in order to minimize soil intervention. In this article, the effects of several types of deck (a reinforced concrete deck, a fiber reinforced polymer deck, and a steel deck are considered) on the weight of the steel truss are examined. Shape optimization of the truss is conducted with the truss height as a variable. Beyond minimizing the weight of the bridge, soil improvement techniques such as deep soil mixing and the preloading of embankments must also be implemented to minimize settlement and increase the bearing capacity of the soil.
International Journal of Bridge Engineering, Vol. 6, No. 1, 2018: pp. 73-90
Theodore G. Konstantakopoulos, George T. Michaltsos
Abstract: The present work studies the behavior of a suspended arch bridge under the action of concentrated or distributed moving loads, proposing a mathematical model for the problem. The studied suspended arch bridge has a dense arrangement of cables, while the described method can easily be extended in the case of a sparse arrangement of cables. A 2D model is considered for the study of the bridge, while the theoretical formulation, is based on a continuum approach that has been used in the literature to analyze such bridges. Finally the obtained equations are solved using the Laplace Transform.
International Journal of Bridge Engineering, Vol. 6, No. 1, 2018: pp. 91-105