Bridge Structures - Volume 8, issue 3-4

Authors: Mahmoud, Khaled M.

Article Type: Other

DOI: 10.3233/BRS-130047

Citation: Bridge Structures, vol. 8, no. 3-4, pp. 91-91, 2012

Authors: Granata, M.F. | Margiotta, P. | Arici, M. | Recupero, A.

Article Type: Research Article

Abstract: A cable-stayed bridge is built by following a construction sequence of different subsequent stages that imply changes of the geometric configuration, restraints and consequently stress and strain patterns. A study is presented about stay stressing sequences in cable-stayed bridges with composite deck for the case of construction made by the cantilever method. Initial cable forces are found through partial elastic schemes of construction stages. Different stay stressing procedures are implemented and a comparison between them is proposed in order to evaluate the differences in terms of deformed shape and internal force distribution of the deck and the pylon. Results can …be useful to give practical suggestions to designers, when they have to deal with stay stressing sequences of composite cable-stayed bridges. Show more

Keywords: Cable-stayed bridge, composite section, stays, stressing sequence, pretension

DOI: 10.3233/BRS-120044

Citation: Bridge Structures, vol. 8, no. 3-4, pp. 93-106, 2012

Authors: Nikolaou, S. | Lacy, H.S.

Article Type: Research Article

Abstract: The densely populated corridor along the Atlantic coast between Boston and the capital of Washington, DC is home to many important bridges in the country. The regional geology is very old, tracing the history of the earth, with bedrock formed more than a billion years ago and surface geology that is very complex and variable. A thorough understanding of the local geologic and tectonic environment is essential to bridge foundation design, which has evolved tremendously from the underwater hand excavation of the caisson foundations of the Brooklyn Bridge to the sophisticated design of the new Woodrow Wilson Bridge. The paper …presents local issues of subsurface conditions, seismic hazard, foundation solutions of old and new bridges, and retrofit schemes for seismic protection of historical bridges based on experience collected over more than a century from Mueser Rutledge Consulting Engineers. Show more

Keywords: Geology of Eastern United States, Fall Line, seismic design, pneumatic caissons, soil structure interaction

DOI: 10.3233/BRS-120043

Citation: Bridge Structures, vol. 8, no. 3-4, pp. 107-119, 2012

Authors: Garapati, S.H. | Kaw, A.

Article Type: Research Article

Abstract: Assembly procedures for assembling steel fulcra of simple-trunnion bascule bridges by heating the girder with heating coils instead of dipping an already stressed trunnion-hub assembly in liquid nitrogen are studied for decreasing the likelihood of failure by cracking and yielding. In the assembly procedure called AP3-A, only the girder is heated to shrink-fit the trunnion-hub assembly in the girder. This assembly procedure AP3-A is found to be infeasible because the girder fails by yielding if heating is expected to be completed in a reasonable amount of time. An alternative assembly procedure called AP3-B is suggested for shrink-fitting where the heating …of the girder is combined with cooling the trunnion-hub assembly in dry-ice/alcohol mixture. This assembly procedure AP3-B is found to be feasible. A complete design of experiments study is conducted on AP3-B to find the influence of parameters like hub radial thickness, and radial interference at trunnion-hub interface on the design parameter of critical crack length – a measure of likelihood of fracture. Critical crack lengths during the assembly procedure AP3-B are quantitatively compared with currently used assembly procedures. The results of this work suggest that increasing the hub radial thickness decreases the likelihood of fracture significantly. For hubs with large radial thickness, heating the girder combined with cooling the trunnion-hub in dry-ice/alcohol mixture (AP3-B) is recommended but for hubs with high radial thickness, multistage cooling of the trunnion-hub assembly in dry-ice/alcohol mixture followed by dipping in liquid nitrogen (AP1- multistage cooling) is recommended. Show more

Keywords: Assembly, bridge design, bridge assembly, bascule bridge, stress analysis, design of experiments, fracture, finite element analysis, shrink-fitting, heating, heating coils, steel fulcra, steel fulcrum

DOI: 10.3233/BRS-120046

Citation: Bridge Structures, vol. 8, no. 3-4, pp. 121-133, 2012

Authors: Yilmaz, Taner | Caner, Alp

Article Type: Research Article

Abstract: Displacement capacity verification analysis is usually used to evaluate the level of displacement at which structural elements reach their inelastic deformation capacities. In engineering practice, a modified version of displacement capacity analysis is used in the seismic performance assessment of bridge structures as an alternative to ductility and drift based approaches. In this seismic performance evaluation for a given target damage level, top bent displacement demand should not exceed a certain fraction of displacement capacity under safety evaluation earthquake level. A limited amount of study is available in the literature addressing the limiting values used in setting target damage levels. …Furthermore, prediction of seismic response of structures over flexible foundations is not an easy task due to the complexities involved in the soil-structure interaction. The focus of this study is to investigate target damage levels by defining a relationship between displacement capacity to demand ratio and strain based damage levels for seismic performance assessment of two column reinforced concrete bridge bents over flexible foundations. Show more

Keywords: CE Database Subject Headings, seismic, bridge, design, displacement, damage

DOI: 10.3233/BRS-120045

Citation: Bridge Structures, vol. 8, no. 3-4, pp. 135-146, 2012

Article Type: Other

Citation: Bridge Structures, vol. 8, no. 3-4, pp. 147-147, 2012

Article Type: Other

Citation: Bridge Structures, vol. 8, no. 3-4, pp. 149-149, 2012