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The present test summaries present the experimental research carried out at the “Politehnica” University of Timisoara, Romania, with the scope of investigating the influence of different column web stiffening solutions on the performance of beam-to-column joints of moment-resisting steel frames. The response parameters, such as resistance, rigidity, and ductility have been monitored. Five different types of panel web stiffening are compared in regard to a reference test. A quasilinear relationship between the moment capacity and the total shear area of the web panel resulted from the experimental tests. The initial rigidity has increased nonproportionally with the same parameter. The investigation of the failure modes proved that fragile failures have been obtained for the specimens with web reinforcement. [ABSTRACT FROM AUTHOR]

Summarizes the results of the full-scale tests on beam-to-column joints, carried out within the experimental program of the COPERNICUS European research project at the Politehnica University of Timisoara, Romania. Test specimens and experimental setup; Data processing; Results and discussion.

The paper presents the outcomes of an experimental program developed and carried out with the aim of characterizing the behavior of two types of moment-resisting joints in multistory frames of concrete-filled high-strength steel rectangular hollow section (RHS) columns and mild carbon steel beams. The paper describes the design approach and displays the specific detailing for the two joint typologies: with reduced beam section (RBS) and with cover plates (CP). In spite of the various past and recent studies which were focused on the evaluation of full-strength welded beam-to-concrete-filled-tube (CFT) column joints, particular design procedures are missing at the European level. The objectives of the current research were to (1) development a design procedure for welded beam-to-CF-RHS joints, (2) experimental validation of the of the design procedure, and (3) assessment of the seismic performance. The monotonic and cyclic tests evidenced a good conception and design of the RBS and CP joints. In particular, the current study proved the feasibility of using higher steel grades in columns and joint components, and the use of an external diaphragm for the transfer the loads from the beam to the side walls of the RHS steel tube. The seismic performance of the joints was proved adequate, the joints sustaining rotation capacities larger than the 40 mrad at the significant damage performance level. [ABSTRACT FROM AUTHOR]

The paper presents the outcome of a finite-element numerical investigation program developed and carried out in connection to a set of experimental investigations performed on welded beam-to-column joints, with columns realized as concrete-filled tubes (CFT) with rectangular hollow sections (RHS). The current study was aimed to calibrate a set of numerical models, to conduct a parametric study, and to validate the proposed design procedure. Joint models were calibrated, and additional parameters were investigated numerically, such as: influence of the concrete core, influence of the axial force in the column, response of one-way and two-way joints. It was shown that (1) the influence of concrete core was proved to be low for the single sided RBS or CP joint assemblies, but significant corresponding to joints with strengthened beam, (2) the response of the joint assembly was not affected by the presence of the axial compression force in the column, and (3) the connection solution with external diaphragms was characterized by an adequate response considering one-way and two-way joints. The current study evidenced a good conception and design of the reduced beam section (RBS) and cover plate (CP) joints. In particular, the study proved the feasibility of using higher steel grades in columns and joint components, and the use of an external diaphragm for the transfer the loads from the beam to the side walls of the rectangular hollow section (RHS) steel tube. [ABSTRACT FROM AUTHOR]

Quite similar large-panel prefabrication technologies were used for residential buildings in East-Europe and some countries in Northern- Europe, e.g. Finland. Even if technologically similar, the fate of the building stocks is different in the two regions, with buildings functioning sustainably in Finland. Hence, one could adapt the maintenance and renovation experiences to the building stock in other countries, creating opportunities for communities and business. The paper presents technological, economical, and institutional/policy aspects in the two environments, and discusses them in the larger framework of European sustainability targets. For major renovation, as targeted in the paper, methods of change management should be applied, entailing thoughtful planning and sensitive implementation and above all, consultation/involvement of the people affected. If the presented interventions would be used in a systematic and planned way, improvements can be achieved for social sustainability targets like e.g. adaptability and visual comfort, while maintaining the safety and security. Finally, the limitations of the approach in light of the institutional setting and ownership structure are discussed, highlighting how different ownership models are favoring or hindering major retrofit interventions. The paper offers ways on strengthening the role of key stakeholders to support major renovation interventions on the panel building stock. [ABSTRACT FROM AUTHOR]

The building sector continues to register a significant rise in energy demand and environmental impact, notably in developing countries. A considerable proportion of this energy is required during the operational phase of buildings for interior heating and cooling, leading to a necessity of building performance improvement. A holistic approach in building design and construction represents a step to moderate construction costs in conjunction with reduced long-term operating costs and a low impact on the environment. The present paper presents an experimental evaluation of the energy efficiency of a building under real climate conditions; the building, which represents a holistically designed modular laboratory, is located in a moderate continental temperate climate, characteristic of the south-eastern part of the Pannonian Depression, with some sub-Mediterranean influences. Considerations for the holistic design of the building, including multi-object optimization and integrated design with a high regard for technology and operational life are described. The paper provides a genuine overview of the energy efficiency response of the building during six months of operational use through a monitored energy management system. The energetic analysis presented in the paper represents an intermediary stage as not all the energetic users were installed nor all the energetic suppliers. However, the results showed a reliable thermal response in the behaviour of recycled-PET thermal wadding used as insulation material in the building and for the intermediary stage in which the building has only secondary energy users, the energetic balance proves its efficiency, keeping the buffer stock of energy high values over 90%. [ABSTRACT FROM AUTHOR]

An important segment of the Romanian urban population, similar to other Eastern European countries, lives in collective residential apartment buildings made using large prefabricated concrete panels. Most of these structures were built between 1960 and 1989 and present major issues concerning aesthetical aspects, lack of internal space, problems related to thermal comfort and, last but not least, weak energy efficiency. The presence of flat roofing system, generally with hydrothermal faults, represents an additional problem which leads to deficient living conditions of the last-storey inhabitants in many cases. Besides other ways of improving the conditions of such apartment houses, the over-roofing is welcome in order to both increase the habitable area and provide adequate roofing for the building. This article presents three types of over-roofing structural solutions, in two solutions, based on intensive use of steel, using (1) hot-rolled steel profiles, (2) rectangular hollow sections and (3) cold-formed steel profiles, respectively. In order to determine the optimum over-roofing system, the study analyses the structural design possibilities and particularly the connection between the new and old structural elements. [ABSTRACT FROM AUTHOR]