Abstract

A study of the variation in axial loads on columns of braced bays along earthquake is presented. Studied columns belong to regular building of 10-, 14- and 18- stories structured with moment-resisting ductile braced steel frames in a chevron configuration. Subject buildings were analyzed under 10 artificial records which were scaled according to the design spectrum for soft soils. The results were compared with published methodologies to estimate the design axial load in columns. Based on the results, a methodology for estimating the design axial load in columns of moment-resisting braced frames is proposed. 

Abstract

The use of steel poles as support structures for lines in Mexico has increased in the last 30 years, mainly due to the increase in urban and suburban sprawl that demand less right of way for this type of infrastructure and less space for their foundations. To fulfill these requirements, numerous studies have been carried out related to dielectric sizing, optimization of the distance between phases to reduce electrical losses, wind hazard associated with the cable-insulator-hardware-structure-foundation system, structural design criteria based on reliability, natural-scale mechanical tests, among others. This article presents some reflections related to the different stages of the design of metal poles for transmission lines, from input data to structural designs, following the criteria of the Mexican electrical industry for a 230 kV pole, 2 circuits, located in Mexicali, B.C.

Abstract

Arch structure is a widely used and important structure type all over the World. Due to its beautiful form and large spanning capacity, arch structure is widely used in bridges, tunnels and other buildings. Recently, the large span space arch structure has a stage of development. The defects of arch structure, such as connection, material, fatigue, stress concentration and welding, will directly affect the safety of these kind of structures. The study of the evolution of the damage in arches is a topic of interest since the antiquity. A well-done structural design should always account for the evolution of the damage in time, in particular if it can bring to a change in the static behaviour of the structure itself under different loading conditions. In this paper, a model for the calculation of localized damaged in arch structures is presented. In particular, using an analytical solution for the computation of the displacements field and the consequent internal actions of very general shapes with variable curvature and tapered cross-section, the damage is modelled by localized depletion of the cross-sectional properties (inertia) in the different points along the arch axis. Moreover, the depleted parameters are the crosssection and the bending stiffness of the arch. The model is applied to the study different configurations of the damage (localization of plastic hinges or different pattern of defects) and to consider the evolution of the damage in time.

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