Construction Of Ceilings Research Articles

Study of Innovative Connector for Steel–Concrete Composite Structures

The paper presents an analysis of the innovative connector for manufacturing a steel–concrete composite beam. The connector consists of a corrugated metal sheet in the shape of a dovetail and shot nails. The nails are shot through the sheet fold into the flange of the steel I-section. Experimental studies of push-out tests were carried out. The conducted tests proved that the proposed solution can be applied as the fastener for steel–concrete composite beams for the construction of ceilings in utility public buildings with small beam’s span. Considering the criteria presented in the Eurocode 4 standard and the results of the experiments, it was proven that all analyzed types of fasteners are ductile. The connector made of sheet with a thickness of 1.00 mm and 2 nails is characterized by a breaking load of 30.83 kN. The load-bearing capacity of the fastener can be adjusted by changing the corrugated sheet thickness and changing the number of nails shot in the single fold of the sheet.

The characteristic design of ceiling

The ceiling as part of the building functions to protect the utility and structure of the room from user visual. Moreover, it protects the user from getting affected by the problems of utility that may occur during the use of the building. The ceiling creates a complete room interior design. In considering those aspects, the ceiling needs to be designed and constructed properly according to the need and type of room. This research aims to identify the characteristics of the design and construction of ceilings. The method is a literature review and study field on various buildings. Data of design is drawn with the computer design program AutoCAD for the main concept. The result shows that the characteristics of the ceiling can be classified based on Support utility such as sprinkler, Cooling system, the material used, Type of ceiling, and ceiling height. Further research needs to consider the local influence on the design and construction system of ceilings.

Protection and Management of the Destroyed Heritage in the Old City of Mosul, Northern Iraq

Mosul has been freed from the clutches of terrorists since 2018, yet the city remains in serious need of reconstruction and redevelopment. The current study attempts to determine whether the fragments of damaged structures can be used in the reconstruction of the old city of Mosul, as well as its economic, cultural, and civilizational feasibility. Old-heritage materials have been categorized into four primary categories, which can be used to avoid confusion while disposing of them. The first category includes antique art elements such as struts, gypsum arches, door frames, and windows, the majority of which were less than 200 years old. The second category included items that were more than 200 years old and were discovered in a few locations, including the Great Mosque of Al-Nuri and the Al-Tahera Church. The third category consists of irregularly shaped stone building materials that were extensively employed in the construction of home walls and ceilings and have survived their engineering characteristics for decades. There are two primary types of stone building materials: limestone and gypsum stone. Finally, plaster, a once-common binder, produced enormous quantities of recyclable materials as well as the new mortar that might be utilized in rebuilding. These significant old-heritage materials went unnoticed and were handled haphazardly. Many of them were removed by massive bulldozers, resulting in the dilemma of their destruction and the search for places to discard them. Recycling these old-heritage materials, according to the study, will help to preserve the irreplaceable artifacts embossed with magnificent ornamentation, sketches, and inscriptions. Obtaining antiquities buried beneath these structures that could be 800 years old or older. Taking advantage of low-cost, high-economic-feasibility building materials and abandoning the idea of destroying and discarding them, which costs a lot of money and pollutes the environment. The geotechnical assessment of categories 1, 3, and 4 revealed that they are recyclable. Category 1 showed that the percentage of damage caused by nature does not exceed 1% and 7% as a result of the war. In categories 3 and 4, the proportion of natural damage caused by weathering does not exceed 1%, while the percentage of natural damage caused by war does not exceed 3%.

Seismic damage thresholds and design methods for two-elevation continuous ceiling systems

The rise-up part of a two-elevation suspended ceiling system, where the ceiling height of two adjacent space or rooms differs due to the usage plan, frequently sustains damage under earthquakes. In current construction practice, the rise-up part in ceilings is temporarily reinforced for construction by the judgment of subcontractors without an engineering design. Thus, this paper addresses seismic damage thresholds and proposes a design method for suspended two-elevation continuous ceiling systems, aiming to provide a rationale for the construction of two-elevation ceilings. First, the vulnerable parts of the ceiling system are examined in a shake table test, where three primary damage patterns are observed. Fragility curves and communications with engineers of a ceiling company indicate a condition of “drift between two elevations ≥1/100” as a threshold for judging a repair need. The analytical model of the rise-up part and the overall two-elevation ceiling are then built to investigate the effects of clearance around ceiling edges, the mass ratio of higher to lower elevation, the distance between TPBBs, and the specification of suspension bars on the seismic behavior of two-elevation ceiling systems. Finally, a design method for two-elevation ceiling systems, including the design flowchart and examples, is proposed.

The Dilemma of Balancing Design for Impact Sound with Environmental Performance in Wood Ceiling Systems—A Building Physics Perspective

Due to the high consumption of resources and energy in the construction sector, the development of resource-efficient and sustainable construction solutions is gaining increasing attention. The awareness of sustainability and resource conservation results in the interest of using natural and renewable materials in contemporary architecture. Timber construction methods offer both constructive and ecological potential for sustainable solutions. From a building physics perspective, the acoustic performance of lightweight buildings, such as those made of timber, presents a challenge. Even if standard requirements are met, the increased low-frequency sound transmission typical for light-weight construction can cause discomfort and is already the subject of questions in building physics, which are currently increasingly extending to timber construction. Within the framework of a holistic approach, this paper compares the problem of acoustic properties, design optimizations and the ecological properties of timber-frame and solid timber construction components. The comparison with heavy materials, such as concrete, shows the relation of acoustic optimization with the change of the environmental profile. In order to establish the interaction between acoustic quality of wooden ceiling constructions and their ecological characteristics, this article aims to demonstrate the potential of materials used in the building sector under ecological aspects considering a life cycle analysis.

English title is no available.

This study considers the urban characteristics of the old city of Fallujah and the impact of the prevailing climatic characteristics on its construction. In particular this study focuses on the suitability of the construction methods and materials for a desert region characterized by high temperatures and a lack of rain. The researcher relied on the analytical and descriptive methodology to reach the research objective. This study concludes that the bot arid conditions encouraged the construction of converging residential dwellings and narrow, twisted streets, designed to produce the largest area of shadows and thereby reduce the air temperature in these areas. The same purpose also contributed to the height of roofs and the selection of building materials used in the construction of walls and ceilings, as well as the distribution of spaces within the housing units.
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Hygrothermal performance of cold ventilated attics above different horizontal ceiling constructions: Full-scale test building

It is often assumed that reduced heat flux to a ventilated attic reduces the temperature and thereby increases the relative humidity. Consequently, the importance of having a tight air and vapour barrier in the ceiling becomes more important with increased insulation. Therefore, in Denmark, the recommendation is to have a tight vapour barrier when re-insulating ceilings against cold ventilated attics to a total of 150-mm insulation material. The recommendation is independent of the insulation material’s hygroscopic properties or the indoor moisture level. The aim of this project was to test the relevance of the recommendation through testing in a full-scale test building (7 × 22 m) with a series of six different ceilings with or without a vapour barrier and variation in the insulation material comprising insulation thickness and its hygroscopic properties. The examination was performed with a controlled indoor climate after an European humidity classes 1–3 and a natural outdoor climate. The study showed very little differences in temperature and relative humidity in the cold ventilated attics, while the humidity class of the indoor climate significantly affects the absolute moisture content in the attic. However, the climate in the attic did not cause mould growth in the test sections, even for humidity class 3. Consequently, in the test building the thickness or hygroscopic properties of the insulation material did not have a significant effect on the moisture level in attics and did not determine whether a vapour barrier should be installed. In this study with the given climate, a vapour barrier is unnecessary in well-ventilated attics if the ceiling is airtight.

Hygrothermal performance of cold ventilated attics above different horizontal ceiling constructions – Field survey

To save energy ceilings towards a ventilated cold attic space are normally insulated. In Denmark the insulation material thickness and type varies but the common used insulation material type is mineral wool or cellulose-based insulation. Furthermore, some attics have vapour barriers, whereas others do not or only have poorly sealed vapour barriers. The effect of these variations on the humidity conditions in cold ventilated attics was investigated in preparation for evaluating the existing recommendations on when and how to add additional insulation to ventilated attics to reduce energy consumption. The investigation has been done by examining and measuring the relative humidity and temperature for at least one year in 34 attics in inhabited single-family houses. In addition, outdoor and indoor temperatures and relative humidity were measured. The results were divided into different groups based on the vapour barrier type, amount of insulation, and insulation material type. Most of the attics were ventilated according to the Danish recommendations. Contrary to the expectations, the thickness of insulation material had no effect on the temperature or relative humidity in the attic. The type of insulation material or the presence of a vapour barrier also did not have any noticeable effect. Apparently, the air change rate (ACH) is more important than the investigated parameters. Combined with previously published results from controlled full-scale experiments, the results from this study are valuable input to new recommendations on how to apply additional insulation in existing ventilated attics.

Features of the Work of Monolithic Flat Floor Slabs Under Construction

The formwork for the construction of monolithic flat ceilings is traditionally carried out by installing supports in spans, in areas where the greatest deflections develop. The installation of temporary supports in the stage of erection changes the design scheme of the plates: zones of negative moments appear in the zone above the additional supports. When concrete reaches the ultimate tensile stresses in the upper zone, cracks appear that can significantly affect the strength and deformation properties of the structure in operation. This work is aimed at revealing the features of the work of plates in the manufacturing stage, their effect on the strength and deformability of the overlapping and the establishment of the optimal location of temporary formwork supports. The object of the study was a cell of a non-beam overlap, measuring 6×9m, the stress-strain state of which was analysed with the help of the Scad program for various arrangements of temporary supports. The plots of the dependence of the influence of the amount of reinforcement in the slab at the time of cracks formation are obtained, as well as the effect of the concrete transfer strength at the time of crack formation. According to the results of the research, the most acceptable options for installing temporary support elements are proposed, which cause the minimum values of negative moments. The results of the article can be used in practice in the construction of monolithic ceilings.

Bending Resistance of Metal-Concrete Composite Beams in a Natural Fire

In this paper, the bending resistance of three metal-concrete composite beams was compared in real car fires in an open car park. Steel and concrete composite beams are often used for the construction of ceilings in multi-storey car parks. The authors made an attempt to evaluate how the replacement of a non-alloy steel girder with a stainless steel or aluminium alloy girder affects the bending resistance of a composite beam under fire conditions. The analysed beams were not fire-protected. They consisted of a concrete slab and a girder made of: non-alloy (<i>carbon</i>) S235J2 (1.0117) steel, X6CrNiMoTi17- 12-2 (1.4571) stainless steel, and AW-6061 T6 (EN AW-Al Mg1SiCu) aluminium alloy.

Coupled heat transfers in a three cavity hollow block subjected to an incident solar flux: Effect of heat conductivity

Hollow blocks or bricks are widely used due to the good thermal insulation, lightweight, and acoustic insulation etc. In this paper, we present a numerical study of heat transfers coupled by natural convection and radiation conduction through a hollow block with three cavities used for the construction of ceilings of buildings. This hollow block is subjected to an incident solar flux and exchanging heat with the air ambient. The governing equations of the mathematical model used for the simulation are discretized by the finite volume method and solved by the SIMPLE algorithm. The main objective of this simulation is to study, in steady state, the effect of the thermal conductivity of the solid partitions on heat flux through this hollow block. The results are presented in terms of streamlines, the isotherms, temperature profiles on the actives surfaces and the obtained global heat flux.

Development of a cellulose-based insulating composite material for green buildings: Case of treated organic waste (paper, cardboard, hash)

Buildings are responsible for 36% of the final energy consumption in Morocco [1-2], and a reduction of this energy consumption of buildings is a priority for the kingdom in order to reach its energy saving goals. One of the most effective actions to reduce energy consumption is the selection and development of innovative and efficient building materials [3]. In this work, we present an experimental study of the effect of adding treated organic waste (paper, cardboard, hash) on mechanical and thermal properties of cement and clay bricks. Thermal conductivity, specific heat and mechanical resistance were investigated in terms of content and size additives. Soaking time and drying temperature were also taken into account. The results reveal that thermal conductivity decreases as well in the case of the paper-cement mixture as that of the paper-clay and seems to stabilize around 40%. In the case of the composite paper-cement, it is found that, for an additives quantity exceeding 15%, the compressive strength exceeds the standard for the hollow non-load bearing masonry. However, the case of paper-clay mixture seems to give more interesting results, related to the compressive strength, for a mass composition of 15% in paper. Given the positive results achieved, it seems possible to use these composites for the construction of walls, ceilings and roofs of housing while minimizing the energy consumption of the building.

Field measurements of moisture variation in cold ventilated attics with different ceiling constructions

Adding insulation material on ceilings against cold ventilated attics is one of the most straightforward tasks of adding insulation. Theoretically, a higher amount of insulation in the attic decreases the temperature and consequently the capability of removing infiltrated indoor humid air. Field measurements of the moisture balance in 20 cold ventilated attics with different amounts of insulation material were analysed. Results show that the amount of insulation material has no decisive effect on temperature in the attic during winter. The moisture level during winter was generally just below the threshold for mould growth.

PCM cooling ceilings in the Energy Efficiency Center – Regeneration behaviour of two different system designs

The regeneration behaviour of two different cooling ceilings with PCM was monitored and analysed with two different methods an analysis of the measured PCM temperatures as well as an analysis of the measured heat fluxes into and out of the PCM modules. The temperatures and heat fluxes then were compared to the measured enthalpy curves of the PCM. Both analysis methods determined the solid fraction of PCM after the regeneration period and yielded very similar results. While the PCM in the cooling ceiling system with the PCM on top of the water pipes was completely liquid only during 5% of the investigated days after the daily heat absorption from the room, the PCM in the cooling ceiling system with the PCM below the water pipes was completely liquid during more than 60% of the investigated days. The regeneration results reflect this differing starting behaviour with typical solid fractions of 90–100% for ceiling type PCM on top and only 80–95% for ceiling type PCM at the bottom. However, since both values are quite high the regeneration behaviour of both PCM cooling ceiling constructions must be considered as very good.

Characteristics of hemp fabric reinforced nanoclay–cement nanocomposites

Cement eco-nanocomposites reinforced with hemp fabric (HF) and nanoclay platelets (Cloisite 30B) are fabricated and investigated in terms of X-ray diffraction, scanning electron microscopy, physical and mechanical properties. Results indicated that the mechanical properties generally increased as a result of the addition of nanoclay into the cement matrix with HF. An optimum replacement of ordinary Portland cement with 1wt% nanoclay decreased the porosity and also significantly increased the density, flexural strength and fracture toughness of HF-reinforced nanocomposite. The microstructural results indicate that the nanoclay behaves not only as a filler to improve the microstructure, but also as an activator to promote the pozzolanic reaction and thus improved the adhesion with hemp fabric. The failure micromechanisms and energy dissipative processes in HF-reinforced cement composite and HF-reinforced nanocomposite are discussed in terms of microstructural observations. These cement eco-nanocomposites can provide new insights for the development of new ‘environmental-friendly nanomaterials’ for building applications such as the construction of sandwich panels, ceilings and roofs.

Determination of the emissions of volatile organic compounds from oriented strand boards and evaluation by the German AgBB scheme

There has been an increasing use of oriented strand boards (OSBs) for the construction of floors, ceilings and walls of buildings. In Germany and other European countries, OSBs are mainly produced from pine wood ( Pinus sylvestris). In response to complaints about the odour and irritation of mucous membranes in connection with the use of OSBs, samples of OSBs were bought from do-it-yourself stores to test their volatile organic compound (VOC) emissions by using emission test chambers. The boards emitted predominantly monoterpenes, aldehydes, acids and acetone. Aldehydes are generated during the production process by the oxidation of unsaturated fatty acids such as linoleic acid. Pine wood, compared with other wood species, contains more unsaturated fatty acids. Of the six acquired OSBs, four boards from three manufacturers would not meet the requirements of the German AgBB (Ausschuss zur gesundheitlichen Bewertung von Bauprodukten, Committee for Health Evaluation of Building Products), mainly because of the emissions of unsaturated aldehydes. These compounds have low LCI values (lowest concentration of interest) and are therefore problematic substances based on a health-related evaluation of building products according to the AgBB scheme.

Calculation of radon diffusion coefficient and diffusion length for different building construction materials

The diffusion of radon in dwellings is a process determined by the radon concentration gradient across the building material structure between the radon source and the surrounding air, and can be a significant contributor to indoor radon inflow. Radon can originate from the deeply buried deposit beneath homes and can migrate to the surface of earth. Radon emanates to the surfaces mainly by diffusion processes from the point of origin following α-decay of 226Ra in underground soil and building materials used, in the construction of floors, walls, and ceilings. In the present study radon diffusion through some building materials viz. coarse sand and stone dust of different grain size has been carried out using LR-115 type II solid-state nuclear track detectors (SSNTDs). The radon diffusion coefficients and diffusion lengths through these building construction materials have been calculated. The effect of grain size on radon diffusion through these building materials shows the decrease in radon diffusion with decrease in grain size.

Aspects of the Construction of Prehistoric Stállo-Foundations and Stállo-Buildings

The so-called stállo-foundations are the most prominent ancient monuments in the mountain areas of Sweden. On the basis of archaeological, historical and ethnological evidence, this paper discusses the type of construction likely to be associated with stállo-foundations dating to the Viking Age. It is argued, in contrast to most accepted ideas, that the stállo-foundations represent the remains of permanent hut dwellings. It is suggested that these huts were built from mountain birch and birch bark, on a bow-pole framework. The surrounding embankments and sunken floors, typical features of the foundations, allowed the construction of low-angled ceilings. This structural design would have enabled the buildings to withstand strong winds and the weight of lying snow, as well as increasing heat retention. In contrast to previous suggestions, that the stállo-sites were inhabited during the summer, we suggest that they were used during the winter. We also suggest that the stállo-foundations represent a system of reindeer herding in which the mountain ridges in the west and areas in Norway were used throughout the year.

Radon diffusion studies through some building materials: Effect of grain size

Radon appears mainly by diffusion processes from the point of origin following α -decay of 226Ra in underground soil and building materials used, in the construction of floors, walls, and ceilings. The diffusion of radon in dwellings is a process determined by the radon concentration gradient across the building material structure between the radon source and the surrounding air, and can be a significant contributor to indoor radon inflow. In the present study radon diffusion through some building materials, viz., soil, sand, fly ash, cement, etc. has been carried out using LR-115 type II solid-state nuclear track detectors (SSNTDs). The radon diffusion coefficients and diffusion lengths through these building construction materials have been calculated. As the rate of radon inflow is dependent upon the porosity and grain size of the materials also, therefore, the effects of grain size on radon diffusion through some of these materials have also been studied. For these studies the materials with different grain sizes, viz. 50, 100, 200 μ m were used. The results indicate that the radon diffusion through these materials decreases with decrease in grain size.

Les origines médiévales d’une technique de charpente : la poutre armée

An inventory of medieval carpentry works has now been conducted for several years in the Middle Rhône Valley. Among the various types of frameworks then in use, the use of trussed beams for the construction of ceilings in the region appears as an original mode of timber framing. The first part of the study deals with this technique through modern treatises on carpentry and writings going back to the Quattrocento. Then follows a technical analysis of the trussed beam in Provence from data provided by texts, the archaeological study of the remains of the Hôtel de Rascas in Avignon and the dendrochronological analysis of woods. A badly known aspect of the architecture of Provence is thus revealed in the light of these data.