The most important aspects of the design, seismic damage evaluation and safety assessment of structures with low ductility like waffle slabs buildings or flat beams framed buildings are examined in this work. These reinforced concrete structural typologies are the most used in Spain for new buildings but many seismic codes do not recommend them in seismic areas. Their expected seismic performance and safety are evaluated herein by means of incremental non linear structural analysis (pushover analysis) and incremental dynamic analysis which provides capacity curves allowing evaluating their seismic behavior. The seismic hazard is described by means of the reduced 5% damped elastic response spectrum of the Spanish seismic design code. The most important results of the study are the fragility curves calculated for the mentioned building types, which allow obtaining the probability of different damage states of the structures as well as damage probability matrices. The results, which show high vulnerability of the studied low ductility building classes, are compared with those corresponding to ductile framed structures.
The codes used in seismic design of waffled-slab floors buildings (WSFB), such as the Spanish NCSE-02 earthquake-resistant design code, assign them restricted ductility, utilise linear structural analysis based on modal analysis, but also consider the structural ductility concept. Uncertainties arise whenever these codes are applied to the special case of buildings with waffled-slab floors, the ductility of which is doubtful. In many cases, during earthquakes, buildings with restricted ductility are unable to reach the ductility values assumed in the design process, although they may exhibit adequate values of overstrength. This paper therefore studies typical WSFB by applying static incremental non-linear analysis procedures (pushover analysis) in order to calculate their actual structural ductility and overstrength values. Fragility curves corresponding to different damage states and damage probability matrices are also calculated and compared with those of momentresisting frame buildings (MRFB) in order to obtain useful conclusions for earthquake resistant design. One of the most relevant conclusions of this article is that the use of a better confinement and of ductile steel can only improve the seismic behaviour of MRFB but not that of WSFB.
Structural engineering companies (SECs) currently have a series of deficiencies that hinder their processes and interactions, decreasing their productivity, lacking collaborative and interconnected processes, not including current work methodologies such as building information modeling (BIM). e BIM methodology seeks to integrate processes and professionals involved in engineering tasks by working on platforms with coordinated and intelligent 3D virtual models. BIM has great potential for structural engineering companies (SEC) and solves their most salient problems. is paper defines a methodology to implement BIM in the SEC, focused on solving the complexities of the design phase, those that make the implementation of BIM in these offices a nontrivial task. Characterized by the optimization of resources, flexibility, and adaptability, the methodology proposed for BIM implementation within SEC clearly and objectively identifies the resources and expectations of the organizations, sets out the requirements necessary to develop the BIM methodology, and provides practical and technical recommendations for planning and monitoring the implementation.
The main objective of this study is to propose a methodology for building a parametric linear model of flexible multibody systems (FMS) for control design. This new method uses a combined finite element (FE)–state-space approach based on component mode synthesis and a double-port approach. The proposed scheme offers the advantage of an automatic assembly of substructures, preserving the elastic dynamic behavior of the whole system. Substructures are connected following the double-port approach for considering the dynamic coupling among them, i.e., dynamic coupling is expressed through the transfer of accelerations and loads at the connection points. The proposed model allows the evaluation of arbitrary boundary conditions among substructures. In addition, parametric variations can be included in the model for integrated control/structure design purposes. The method can be applied to combinations of chainlike or/and starlike flexible systems, and it has been validated through its comparison with the assumed modes method (AMM) in the case of a rotatory spacecraft and with a nonlinear model of a two-link flexible arm.
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