Transformation of Socialist Realistic Residential Architecture into a Contemporary Sustainable Housing Habitat—General Approach and the Case Study

This article deals with the problem of multi-family housing implemented in the 1950s in Poland. Buildings from this period are located in the central districts of cities, and are well-connected and equipped with service infrastructure, but due to the small size of these flats, their low standard and poor technical condition, they are not sufficiently attractive for middle-class people and developing families. The consequence of this is the social selection of residents and the disappearance of neighborly relations. In this article, the authors present a balance sheet of the shortcomings and advantages of these buildings, and against the background of contemporary requirements for housing, resulting from the theory of sustainable development, they indicate possible directions for modernization. Detailed solutions are presented for a specific housing complex located in Rzeszów. The development of flat roofs and the introduction of functions integrating the community of residents are the significant elements of the project. Due to the fact that the functional layouts of stories, the structure of buildings, and to a large extent the spatial arrangement of residential complexes were unified in the 1950s throughout the whole country, the presented concept may serve as inspiration for similar projects undertaken in any other city in Poland.

The Benefit of Horizontal Photovoltaic Panels in Reducing Wind Loads on a Membrane Roofing System on a Flat Roof

The present paper proposes a measure for improving the wind-resistant performance of photovoltaic systems and mechanically attached single-ply membrane roofing systems installed on flat roofs by combining them together. Mechanically attached single-ply membrane roofing systems are often used in Japan. These roofing systems are often damaged by strong winds, because they are very sensitive to wind action. Recently, photovoltaic (PV) systems placed on flat roofs have become popular. They are also often damaged by strong winds directed onto the underside, which cause large wind forces onto the PV panels. For improving the wind resistance of these systems, we proposed to install PV panels horizontally with gaps between them. Such an installation may decrease the wind forces on the PV panels due to the pressure equalization effect as well as on the waterproofing membrane due to the shielding effect of the PV panels. This paper discusses the validity of such an idea. The pressure on the bottom surface of a PV panel, called the “layer pressure” here, was evaluated by a numerical simulation based on the unsteady Bernoulli equation. In the simulation, the time history of the external pressure coefficients, measured at many points on the roof in a wind tunnel, was employed. It was found that the wind forces, both on the PV panels and on the roofing system, were significantly reduced. The reduction was large near the roof’s corner, where large suction pressures were induced in oblique winds. Thus, the proposed method improved the wind resistance of both systems significantly.

Quantification of existing rooftop PV hourly generation capacity and validation against measurement data

The spatio-temporal patterns of the existing rooftop photovoltaic (PV) production can provide valuable insights for the design of effective strategies for PV integration at large scale. In this work, we quantify the hourly production of existing rooftop PV installations by combining two large-scale methods, for detecting rooftop solar panels and for estimating their hourly PV generation, which are both applicable at the Swiss national scale. A validation against measured data of PV installations from 16 roofs in the Swiss Canton of Aargau shows that the existing PV area is detected accurately, while the hourly profiles overestimate the PV production, with higher errors in winter than in summer. These errors result in a mean overestimation of the annual PV production by 16%, assuming a triangular panel placement at low tilt (15°) on flat roofs.

Minimization of a point thermal bridge by a roof restraint system holder

Roof restraint systems are designed for flat roofs for safe maintenance and repairs. By anchoring them, considerable point thermal bridges are created, which can also lead to condensation in the roof cladding. We deal in this work with the design of minimization of these point thermal bridges.

INVESTIGATION OF TECHNOLOGICAL PARAMETERS OF THE DEVICE AND REPAIR OF THE BASES OF FLAT ROOFING

In the practice of modern construction, light concretes of low thermal conductivity are used as a thermal insulation layer of enclosing structures. In particular, they are used for insulation of flat roofs of buildings for various purposes. One of their effective methods of thermal insulation is the use of polystyrene concrete of low average density and thermal conductivity directly in building conditions. Studies have established the rational selection of the composition of this type of concrete for the device of a monolithic thermal insulation layer, the resource support of the technological process, including the mechanization of work and qualification requirements for performers. The improvement of organizational and technological solutions of flat roofs based on the choice of rational parameters of technological processes and operations ensures a reduction in the complexity, duration and cost of work on the construction site.

Wind-Induced Dynamic Behavior of Mechanically Attached Single-Ply Membrane Roofing Systems Installed on Flat Roofs

The present paper investigates the wind-induced dynamic behavior of a mechanically attached single-ply membrane roofing system installed on flat roofs of middle-rise and high-rise buildings with or without parapets. First, the wind pressure distributions on the roof were measured in a turbulent boundary layer. The results indicate that the parapets affect the wind pressure distributions significantly. Very large peak suctions are induced near the windward corner of the roof in an oblique wind in the case of a building without parapets. Then, we have developed a test method for evaluating the wind-resistant performance of the roofing system using three Pressure Loading Actuators (PLAs) and a chamber to which a full-scale specimen is attached. In the experiments, the chamber was divided into three spaces by using thin silicon sheets. The PLAs generated different fluctuating pressures in these spaces using the time history of wind pressure coefficients measured at three points near the windward corner of the roof in an oblique wind. We measured the membrane deformations and the wind forces acting on the fasteners connecting the membrane with the structural substrate. The results indicate that horizontal forces nearly equal to or larger than the vertical ones are generated on the fasteners, which may cause pulling out of fasters more easily. The failure mode was found to be different from that obtained from a ramped pressure loading test. We have also developed a model of finite element analysis, which was validated by an experiment. The results of analysis for a wide area of roofing system indicate that relatively large horizontal forces may be generated on the fasteners in the field region of the roof for buildings with parapets.

State of Conservation of Concrete Heritage Buildings: A European Screening

Historic concrete buildings are at risk. Limited knowledge of concrete technology until the 1960s led to more sensitive buildings than modern concrete buildings. In addition, the lack of sensibility regarding their heritage value and insufficient protection is leading to remorseless demolition. Still, concrete has proved to be a resilient material that can last over a century with proper care. There is not yet an estimation of the status of historic concrete buildings in Europe. Until now, a few attempts have been done to secondarily, and subjectively, gauge their conservation status. This paper is the result of a joint investigation studying forty-eight historic concrete buildings distributed in four countries. They were surveyed by expert teams according to a predefined methodology. The study aims to identify recurrent damages and parameters affecting the conservation state. It also aims to serve as the first trial for an objective and measurable methodology, to apply it with a statistically significant number of cases. Damages related to the corrosion of reinforcement and moisture-related processes were the most recurrent. The use of plasters, flat roofs, and structural façade walls show a positive effect in protecting the concrete. The state of conservation has a great variability across countries.