Floor Construction Research Articles

Impact noise calculations of CLT constructions using finite element

Cross-laminated timber (CLT) consists of multiple glued layers of wood, which have perpendicular orientation with respect to adjacent layers, and it has become an important building material due to its light weight, strength, and sustainability. One problem with CLT constructions is the impact noise, which for a bare CLT floor is poor. There thus is a need for calculation tools that can predict impact noise level of such floor constructions. For composed constructions, finite element is a flexible and usable tool. However, to simulate real measurement scenarios, the force produced by the ISO tapping machine then needs to be estimated. This paper revisits this estimation and performs calculations of the impact noise level of a CLT floor, and compares this with measured results.

Extending the frequency range of ISO 717-2 - a look at options and issues

In 2019, the Norwegian Standard NS 8175, which defines requirements for sound insulation in Norwegian buildings, was revised to include low frequency spectrum adaption terms for new dwellings. This change affects the applicability of measurements of weighted improvement of impact sound insulation, delta Lw, as the spectrum for calculating delta Lw, given in ISO 717-2, is limited downwards to 100 Hz. For a floating floor construction, this means that floors with a resonance frequency well below 100 Hz, and correspondingly a relatively high delta Lw, will be overrated in the sense that the measured delta Lw will be unaffected by the poor low frequency performance of the floating floor. To properly address this increased focus on low frequencies, an extended range spectrum is needed. In the work leading to this paper, a selection of extended range values for the reference heavyweight floor have been suggested, starting with a linear extrapolation of the values given in ISO 717-2. Data from laboratory measurements of delta Lw for floating floors have then been used to investigate the suitability of the suggested values. The results are summarised and discussed in this paper.

АЛЬТЕРНАТИВНОЕ ИСПОЛЬЗОВАНИЕ НЕСУЩИХ ЭЛЕМЕНТОВ ИНВЕНТАРНЫХ ОПАЛУБОЧНЫХ СИСТЕМ ПРИ МОНТАЖЕ И ДЕМОНТАЖЕ ЖЕЛЕЗОБЕТОННЫХ ПЕРЕКРЫТИЙ

The paper substantiates the expediency of using widespread load-bearing racks, frame systems and beams for the construction of formwork monolithic floors of multi-storey civil construction in other types of construction work in prefabricated monolithic construction and reconstruction of civil facilities. Examples and descriptions of organizational and technological schemes for the construction of prefabricated monolithic frames with the use of inventory spatial frames and racks of adjustable length with glued wooden beams, mainly from well-known Doka and PERI companies, as supporting elements for the organization of alignment and temporary fixing of hollow floor slabs during their installation. Examples of the use of the same bearing elements of formwork systems in projects of reconstruction and liquidation of multi-storey civil facilities are presented. In these cases, they were intended to ensure the stability of the reconstructed parts of buildings during their separation and extraction according to the intended parts. For this purpose, the schemes of using diamond cutting technologies of reinforced concrete structures patented by the authors in reconstruction projects of civil buildings in the Crimea are shown. Subject of research: technological equipment for the production of construction, installation and reconstruction works to ensure their efficiency and safety using beams, frames and racks of inventory formwork systems of monolithic and prefabricated reinforced concrete floors. Materials and methods: analysis of the state of the issue according to literary and patent sources, justification of expediency and modeling of technology and organization of construction, installation and reconstruction works at specific civil facilities in Crimea, assessment of economic efficiency, industrial and environmental safety of the proposed innovations. Results: organizational and technological schemes for the installation of temporary supporting and regulating systems for the installation and dismantling of reinforced concrete floors made up of inventory elements of industrial formwork systems of both domestic and foreign origin are reasonably presented. The technological and economic efficiency, as well as the technical and environmental expediency of innovations for reasons of life safety are shown. Conclusions. The expediency of using elements of inventory formwork systems of monolithic floors to create temporary supporting structures from them during the installation and dismantling of reinforced concrete floors is shown. Examples of such applications are presented when installing ceilings of prefabricated monolithic frames of specific civil facilities, as well as diamond cutting of similar structures during their reconstruction or liquidation.

Effects of Macro Fibers on Crack Opening Reduction in Fiber Reinforced Concrete Overlays.

Macro fibers have been extensively used in the construction of various concrete structures, including bridges, dams, tunnels, industrial floors, and pavements. However, their effectiveness in reducing crack opening widths in concrete pavements has not been fully explored. This study aims to delineate the role of fibers by identifying the optimal types and volumes for effectively controlling cracks in concrete pavement structures, particularly in thin overlays. The research investigates how different fiber types, such as synthetic and steel, and their respective volumes can mitigate crack propagation in concrete overlays. Additionally, it evaluates the performance of fiber-reinforced concrete overlays compared to conventional dowel bar systems in terms of crack width reduction and overall pavement durability. The findings aim to provide specific design criteria for incorporating macro fibers in concrete overlays to enhance structural integrity and longevity.

Influence of Polymer Fibre Reinforcement on Concrete Anchor Breakout Failure Capacity.

With the increasing use of fibre-reinforced concrete, e.g., in industrial floor and tunnel construction, the associated fastening technology in this material has increasingly become the focus of scientific attention in recent years. Over 25 years ago, design and assessment guidelines for anchoring systems in reinforced concrete were established, which have since evolved into comprehensive regulatory standards. However, these standards only address plain and rebar-reinforced concrete as anchoring bases, neglecting fibre-reinforced concrete. The design of anchorage systems in fibre-reinforced concrete has not yet been standardised. Recent studies and product certifications accounting for steel fibre reinforcement are now seeing their way to publication, supported by a fair amount of scientific research studies. This paper aims to elucidate the effects of polymer fibre reinforcement in this application through a systematic investigation. Experimental studies were conducted to evaluate the system's load-bearing behaviour failing with concrete breakouts under tensile loading. By incorporating the determined material properties of polymer fibre-reinforced concrete and their mathematical interpretation, alternative model proposals are presented to assess concrete breakout resistance. The addition of polymer fibres significantly improves the load-bearing capacity and ductility of concrete under tensile loads, transforming its quasi-brittle response into a more ductile behaviour. Although the fibres had a minor impact on overall material strength, their influence on the tensile capacity of the anchors reveal a 15-20% increase in load resistance and up to a doubling of the failure displacements.

Airborne acoustic assessment of impact-resistant fitness flooring systems

Fitness facilities in residential and mixed-used commercial buildings introduce important acoustic design challenges that must be considered in a building. Cardio activities such as running on treadmills, group classes for high intensity training, and weight training areas introduce high levels of unwanted noise and vibration into a building structure. Isolated floor constructions are generally coordinated and implemented during design but are not practical when buildings are completed and occupied. Impact-resistant fitness flooring systems are typically explored and installed as an alternate approach to reduce the transmission of impact noise and vibration. Non-standardized field airborne noise measurements of weight drops were conducted on an existing gym and on four possible impact-resistant fitness flooring upgrades to assess the reduction of impact noise levels in the offices located below the gym. The measurements were also compared to the HVAC background noise levels to observe the increase above background conditions and provide a subjective evaluation. The results of the measurements show that impact-resistant fitness flooring systems provide a noticeable reduction of impact noise, compared to standard fitness flooring systems. The results also show that impact-resistant fitness flooring systems that include specialty engineered shock pads as a base layer provide a significant reduction of impact noise levels.

Recovering the Historical Construction and Materials of Erik Gunnar Asplund’s Stockholm Public Library

This work presents the first detailed study of the construction and materials of the Stockholm Public Library. As the building undergoes a rare period of maintenance and renovation, the floors and walls of the library are examined from three perspectives. First, using available but limited archival documents and plans; second, with non-destructive ground-penetrating radar measurements; and finally, through on-site surveys during local interventions for the maintenance and renovation process. The ensuing results emphasize the complementary nature of this combined research approach in recovering lost or forgotten construction details and further reveal several important findings. In the case of the unique wall finishing of the library’s rotunda, multiple layers of lime mortar, each varying in thickness and coarseness, were used to build up and craft the relief-like interior wall surface. With the use of in-situ aerated concrete and prefabricated Solomite panels in the library’s 1931–32 floor construction, a material connection between Asplund and the broader modern movement in architecture is further highlighted. At first glance, these construction-related findings seem to reinforce the common architectural narrative of the library as a transitional project between neoclassicism and modernism. At the same time, however, the library’s separate periods of construction of 1925–28 and 1931–32 and their distinct materials can be seen as a continuity of construction culture, with the innovative use of local raw materials related to the Swedish landscape.

Estimate the impact of deep excavation construction in high-rise buildings on neighboring structures

The estimation of diaphragm wall displacements and soil movement around the deep excavation of a high-rise building during the construction of basement floors plays a crucial role in limiting risks that may cause damages to human lives and property during the construction process. This study proposes the use of Finite Element Analysis (FEA) to accurately predict the behavior of soil and diaphragm walls in deep excavations of high-rise buildings. The model is based on advanced soil models and considers the interaction between diaphragm walls and soil, enabling the prediction of adverse impacts during the construction process, as well as negative effects on adjacent buildings. Additionally, the study will analyze and highlight the primary parameters that negatively impact the excavation process and neighboring constructions.

Practical experience of installing an artificial base for industrial floors

The installation of artificial foundations for industrial buildings and constructions (industrial floors) is becoming more and more relevant in modern construction, as the number of satisfactory sites for development is decreasing, territories with complex geological and hydrogeological conditions are increasingly being used. A high-quality installation of an artificial base should ensure the durability, strength and stability of the structure. When preparing the site and arranging the artificial base, it is necessary to take into account such important factors as the type of soil, the level of groundwater, the expected load on the floor and the type of floor covering. Compliance with the requirements of regulatory and technical documentation, the use of quality materials and professional execution of work are critical for the successful construction of industrial floors. As part of the study, an overview and detailed description of the process of installing an artificial base for industrial floors was carried out on the example of a real construction, a warehouse complex with an area of 35,000 m² in the south-western outskirts of the city of Kyiv. The article highlights that the foundation installation process includes two main stages: site preparation and creation of artificial foundation layers. The preparation of the site includes cleaning and planning of the territory, removing and removing the fertile layer of soil, conducting engineering and geological studies and implementing measures for the engineering protection of the territory. The arrangement of the artificial base includes the compaction of the existing soil layers, the creation of new artificial base layers and their mechanical compaction in combination with the reinforcement of the layers with geosynthetics materials (geogrids). This study emphasizes the importance of a comprehensive approach to site preparation and artificial base installation, which allows for reliable and long-term operation of industrial floors, minimizing the risks of deformation and damage.

Hysteretic Performance Analysis of Prefabricated Steel-Concrete Composite Edge Joints Considering Floor Composite Effects

ABSTRACT This study conducts quasi-static tests and finite element (FE) analysis by using ABAQUS software to examine the effects of floor combination effect (FCE) on the seismic behavior of a novel type of prefabricated steel-concrete composite (PSCC) exterior joints. This analysis assesses PSCC exterior joints featuring bolted-welded hybrid connections, focusing on their seismic performance under the influence of FCE. The variables in this research include floor construction parameters, axial compression ratio (n), and core area concrete (CAC). The results indicated that these variables, particularly the floor construction parameters, n, and CAC, significantly influence stress distribution and magnitude within the joint core area (JCA) and the floor slab. Although the floor construction parameters exert a minor effect on seismic performance, increasing n markedly enhances the joints’ load-bearing and energy dissipation capacities. However, it also makes the joints more susceptible to brittle failure. Optimal bearing capacity and ductility for energy dissipation are achieved when n equals 0.3. In addition, CAC substantially increases the initial stiffness (IS) and bearing capacity, with a peak increase in bearing capacity of approximately 18% and an IS enhancement of around 25%. However, rising CAC strength has a relatively minor impact on seismic performance.

Dating mortars and bricks of Santalla de Bóveda Monument (Lugo, NW Spain)

Santalla de Bóveda Monument (Lugo, NW Spain) is a small semi-buried building, under the Bóveda parish church, built in the 18th century, with an apsidal quadrangular floor plan, which was divided into three naves, a small vaulted apse and a rectangular floor plan vaulted, where paintings depicting birds and plant elements have been well preserved. The monument has aroused great interest since its discovery, but its chronology and functionality has always been the subject of controversy. Several hypotheses have suggested that the monument was built in the Roman period and some others around the 5h, 8th or 9th century AD. However, any direct evidence or absolute age has been provided until today. The stratigraphic analysis of the building suggests five constructive phases. Bricks and mortars of all phases were sampling to perform absolute dating techniques and to get a precise and accurate chronology. Radiocarbon dating of mortars and Optically Stimulated Luminescence (OSL) dating of bricks and mortars have been used to this purpose. A total of 34 samples were taken, being 20 used for luminescence (mortars and quartz aggregates) and 15 used for 14C ages (charcoal fragments of lime mortars). 5 brick samples were also dated by Thermoluminescence (TL). The obtained ages have allowed, for the first time, stablishing an accurate and precise chronology being the first phase assigned to the 4th Century AD. Alterations of the building and the vault paintings were performed in the early 7th century, while the construction of the second floor and occasional repairs were performed during the 10th-12th centuries.

Evaluation of platelet-rich fibrin versus collagen membrane for enhancing healing of secondary grafted alveolar cleft: a randomised controlled trial

The purpose of this study was to compare the efficiency of using autologous platelet-rich fibrin versus a resorbable collagen membrane in secondary alveolar bone grafting. Patients were randomly allocated to the three treatment groups: Group 1 - twelve children in whom the nasal layers of the alveolar clefts were repaired using autologous platelet-rich fibrin with autogenous chin bone; Group 2 - twelve children in whom the nasal layers of the alveolar clefts were repaired using bovine collagen membrane type I (Colla-D) with autogenous chin bone; and Group 3 - twelve children in whom the bony alveolar clefts were grafted with autogenous chin bone after construction of a watertight nasal floor had been completed. The study population comprised 36 patients with alveolar clefts, ranging in age from seven to 12 years. At the last follow-up period all groups had stable healing conditions and good radiological outcomes in terms of the alveolar bone height bordering the teeth (both mesially and distally) and the incorporation of grafting material with the surrounding bone. The use of either a PRF membrane and a collagen membrane as an interpositional layer between the nasal layer and the autogenous chin bone graft enhanced bone formation and density in alveolar clefts compared with the control group.

Damage detection of lightweight concrete dual systems reinforced with GFRP bars considering various building heights and earthquake intensities

Because of their distinct mechanical, rheological, and physical features, lightweight concrete and glass fiber reinforced polymers (GFRP) bars have a significant growth in the modern building sectors over the past decade. Minimizing subsequent quake damages, particularly in multistory residential or administrative RC structures, is a key concern for governments in earthquake zones. The dual frame-wall system is among the most appropriate structural systems for resisting seismic loads in multistory concrete structures. Therefore, this research aims to quantify the seismic damage of multistory dual frame-wall systems with varying heights of 12, 20, and 25 stories under mild, medium, and severe earthquake intensities. The inelastic damage analysis of RC buildings program is utilized to nonlinearly analyze 54 cases containing various materials such as normal concrete, lightweight concrete, steel reinforcement bars, and GFRP bars. Using lightweight concrete with half the density of normal concrete and pure linear-elastic GFRP bars in floor construction will significantly decrease the geometric nonlinearity effect created by the load-displacement (P-Δ) effect and dissipate a large amount of the kinetic energy generated by seismic excitation, resulting in a significant reduction in post-earthquake damage. When compared to the normal concrete, using lightweight concrete in floor construction reduced the mean story damage index by 14–20% as the building's height increased, while reinforcing these floors with GFRP bars resulted in substantial decreases in the overall damage index, reaching about 57–68% when both building's heights and seismic excitation intensities were considered.

Efficiency of Pile Foundation in the Construction of Basement Floors of Structures on Collapsible Soil

Efficiency of Pile Foundation in the Construction of Basement Floors of Structures on Collapsible Soil

Seismic Retrofit of Concrete Buildings Damaged by Corrosion: A Case Study in Southern Italy

A case study of a building in southern Italy, subjected to high degradation by corrosion and waiting to be assessed for retrofit interventions, is presented. The owner required modifications to the building configuration, including a new layout of the floors and retrofitting for a high level of seismic load. A double strategy of an assessment and retrofit was carried out: dynamic linear and static non-linear analyses were performed, and the results were compared. Afterwards, a global strategy of mass and stiffness redistribution was implemented together with different retrofit interventions on the foundations, columns, and beams of the framed structure, such as reinforced concrete and steel jacketing, the application of FRP plates and fabrics, new steel elements, and steel–concrete composite floors. The results of the intervention are discussed and the implications of corrosion on the structures are explored. From the results obtained, it is possible to see how the use of different techniques for strengthening and passive seismic protection strategy can allow engineers to obtain the result of structural adaptation to earthquakes with low-cost interventions. The widespread adoption of steel jackets, coupled with the construction of floors using a steel–concrete composite structure, grants a good confinement of the beam–column r.c. joints, together with the overall strengthening of the existing structure. The adoption of CFRP wrapping at the lower edge of the beams implies a limited increase in thickness and the limited interventions of partial demolition from the existing structural members. A critical review of the steel jacketing aspects in terms of bending and shear strengthening is reported by considering this technique in the form of a steel exoskeleton containing the damaged concrete structure, by confining concrete elements, and by increasing the performance for both gravitational and seismic loads.

Composite Delta Beam for Slim Floor Construction

Abstract: The structural behaviour of the composite Flush Beam for slim floor as a whole has been investigated. The deformation behaviour of the structural members Steel beams with trapezoidal cross-sections and specially punched webs were developed as composite beams in slim floors. The estimation of the flexural stiffness and bending capacity of composite slim beams is rather complicated, because the influence of many factors should be taken into account. These factors include variable section dimensions, Profile of the beam, stiffness of the beam and interaction between steel and concrete. In this paper, analytical investigations have been conducted to investigate the deflection behaviour of Flush beam specimens under monotonic loading. A design procedure is developed for composite slim floor Flush beams based on cross-sectional analysis and the flexural properties of the slim floor beams are evaluated. From the analytical investigation it was found that the deflection of delta beam is 48% less than the conventional I-beam More over the stiffness of the Delta beam is 49.8% higher than the I-beam

Properties of Fine-Grained Cement Composites, with a Special Emphasis on Cement Screeds in Floor Constructions

Through experimental research and theoretical analysis, this study primarily aimed to compare the behavior of cement screeds made in a traditional manner with those made with the addition of microreinforcement. The study also explored the possibility of using electrofilter ash as a component of screeds, examining the advantages and disadvantages of partial substitution of cement with fly ash. The contribution of this article is the experimental research on the characteristics of fresh and hardened cement composites, as well as the parameters influencing the structure and behavior of cement screeds during their use. It has been determined that by using electrofilter ash as a partial replacement for cement, satisfactory values of physical–mechanical and deformation characteristics of fine-grained cement composite can be achieved. Through analysis of the obtained results and influential parameters of these composites, the optimal design approach has been explored. This relevant information could potentially provide reliable recommendations to designers and contractors for the production of quality and durable cement screeds.

Evaluating the measurement of the velocity level difference for building constructions which combine Type A and Type B elements

The standard ISO 12354 outlines a method of predicting the transmission of structure-borne noise in buildings based on data measured in a laboratory or in the field, measured in part according to the standard ISO 10848. The ISO 10848 standard describes procedures for the measurement of both the normalized flanking level difference and the velocity level difference of flanking paths through different building constructions and the junctions between them. Both the normalized flanking level difference and the velocity level difference were measured for a hybrid construction of a cross-lamented timber floor (Type A element) connected to lightweight timber walls (Type B elements) in the National Research Council Canada’s four room flanking facility. The predicted normalized level differences are compared against the measured values to evaluate the prediction method for constructions that mix Type A and Type B elements.

Bowling alleys in residential buildings—Noise control and measurements

In the competitive world of residential development, developers are striving to construct residential buildings that will be more desirable to occupants by providing a diverse range of amenity spaces, such as a bowling alley. Understandably, noise concerns from the addition of bowling alleys in residential buildings were raised during the design stage of various projects. To address the issues, a jack-up floating floor system was proposed for the bowling alley to mitigate the noise impact from the pin setting machine, initial ball impact on the bowling alley lanes, rolling on the lanes, and ball impact with the pins. Apparent Impact insulation class (AIIC) and heel drop testing were completed at various stages during the floating floor construction to confirm the impact sound isolation performance of the floating floor system. Testing results concluded that the implemented floating floor system reduced impact noise significantly and satisfactory sound levels resulted in the closest occupied spaces.

Reuse of cut concrete slabs in new buildings for circular ultra-low-carbon floor designs

The study explores an original idea that responds to the urgent need to reduce the detrimental environmental impacts of load-bearing floor construction in new buildings by reusing saw-cut reinforced concrete (RC) pieces salvaged from soon-to-be demolished structures. Cutting and reusing large RC pieces rather than crushing them to rubble is an untapped emerging circular construction method with a high potential for reducing waste generation, natural resource consumption, and upfront greenhouse gas emissions. Through an iterative design and analytical process, the study demonstrates how discarded cast-in-place RC floors can be cut and reused to build new low-carbon, little-extractive, load-bearing building floors. The study provides two new floor design solutions that valorise frequently discarded construction components (reinforced concrete slabs and steel profiles), combining construction technologies already used by the industry. The parametric design of 20′280 combinations of donor and receiver structures and their environmental analysis through Life-Cycle Assessment show that the new floor systems have shallow detrimental environmental impacts, with a reduction of upfront greenhouse gas emissions averaging 80 % compared to conventional practice. Floor-system solutions as low as 5 kgCO2e/m2 have been obtained. Structural assessments additionally show that flat slabs that are currently demolished meet the structural requirements at the preliminary design stage for reuse in new office or housing buildings. In particular, thanks to mandatory minimum reinforcement, 18-cm thick or thicker flat slabs built in Switzerland after 1956 and spanning up to 4 m are expected to be technically reusable as-is over their entire span. Overall, this study sets up a new benchmark for innovative floor systems with minimum environmental impacts and calls for considering soon-to-be demolished RC structures as mines of valuable construction components.