Seismic design optimization of multi–storey steel–concrete composite buildings

This work presents a structural optimization framework for the seismic design of multi–storey composite buildings, which have steel HEB-columns fully encased in concrete, steel IPE-beams and steel L-bracings. The objective function minimized is the total cost of materials (steel, concrete) used in the structure. Based on Eurocodes 3 and 4, capacity checks are specified for individual members. Seismic system behavior is controlled through lateral deflection and fundamental period constraints, which are evaluated using nonlinear pushover and eigenvalue analyses. The optimization problem is solved with a discrete Evolution Strategies algorithm, which delivers cost-effective solutions and reveals attributes of optimal structural designs

Structural optimization in steel structures, algorithms and applications

L'abstract è presente nell'allegato / the abstract is in the attachmen

Hybrid cold-formed steel structural systems for buildings

Cold-formed steel (CFS) shear walls or strap-braced walls are the primary lateral load resisting components in light-weight steel framed (LSF) structures. Despite the increasing demand on the application of CFS systems in mid-rise construction, the relatively low lateral load resistance capacity of these systems has remained one of the major obstacles for further growth, as this low resistance becomes problematic in their use in cyclonic wind regions or highly seismic zones. In this thesis, in order to address this issue, a new Hybrid CFS wall composed of CFS open sections and square hollow sections (SHS) is developed and investigated. The proposed hybrid system is suitable for light-weight steel structures for mid- to high-rise construction, due to its satisfactory lateral load resistance. The thesis presented provides the results of the study which contains experimental and numerical investigation as outlined in the following. In the first stage of this study, a comprehensive literature review was conducted to reveal the existing gaps in the previous studies on CFS structures under lateral loads. In the second stage, a series of full-scale experimental tests were performed on seventeen hybrid CFS wall panels in order to investigate their lateral performance, shear resistance, failure modes and energy absorption. In the third stage of this thesis, a comprehensive study was performed on the theories and applications of the numerical models for analysis of the lateral behaviour of CFS wall systems during the past several decades, and all existing numerical methods for simulating the behaviour of CFS shear walls were accordingly classified. In stage four of this study, proposed hybrid wall panel was further developed, and twenty new wall configurations were evaluated using non-linear finite element analysis, aiming to further investigate the seismic performance of CFS hybrid walls. Finally, in the last stage, a sustainability analysis was performed which could be of interest to all stakeholders including owners, builders and investors, when assessing the potential use of hybrid CFS systems, in particular for mid-rise buildings

Sustainable Structural Design for High-Performance Buildings and Infrastructures

Exceptional design loads on buildings and structures may have different causes, including high-strain natural hazards, man-made attacks and accidents, and extreme operational conditions. All of these aspects can be critical for specific structural typologies and/or materials that are particularly sensitive. Dedicated and refined methods are thus required for design, analysis, and maintenance under structures’ expected lifetimes. Major challenges are related to the structural typology and material properties. Further issues are related to the need for the mitigation or retrofitting of existing structures, or from the optimal and safe design of innovative materials/systems. Finally, in some cases, no design recommendations are available, and thus experimental investigations can have a key role in the overall process. For this SI, we have invited scientists to focus on the recent advancements and trends in the sustainable design of high-performance buildings and structures. Special attention has been given to materials and systems, but also to buildings and infrastructures that can be subjected to extreme design loads. This can be the case of exceptional natural events or unfavorable ambient conditions. The assessment of hazard and risk associated with structures and civil infrastructure systems is important for the preservation and protection of built environments. New procedures, methods, and more precise rules for safety design and the protection of sustainable structures are, however, needed

A Proposal for a Three Detector Short-Baseline Neutrino Oscillation Program in the Fermilab Booster Neutrino Beam

A Short-Baseline Neutrino (SBN) physics program of three LAr-TPC detectors located along the Booster Neutrino Beam (BNB) at Fermilab is presented. This new SBN Program will deliver a rich and compelling physics opportunity, including the ability to resolve a class of experimental anomalies in neutrino physics and to perform the most sensitive search to date for sterile neutrinos at the eV mass-scale through both appearance and disappearance oscillation channels. Using data sets of 6.6e20 protons on target (P.O.T.) in the LAr1-ND and ICARUS T600 detectors plus 13.2e20 P.O.T. in the MicroBooNE detector, we estimate that a search for muon neutrino to electron neutrino appearance can be performed with ~5 sigma sensitivity for the LSND allowed (99% C.L.) parameter region. In this proposal for the SBN Program, we describe the physics analysis, the conceptual design of the LAr1-ND detector, the design and refurbishment of the T600 detector, the necessary infrastructure required to execute the program, and a possible reconfiguration of the BNB target and horn system to improve its performance for oscillation searches.Comment: 209 pages, 129 figure