Floor Structure Research Articles

An innovation in the method of assessing the fire resistance of a reinforced concrete girderless ceiling of a building

The article presents a new method for assessing the fire resistance of monolithic girderless non-accumulating floors of buildings and structures. The essence of the method lies in the fact that thermal (fire) tests of the floor are carried out without destruction, according to a set of single indicators of the quality of working fittings and structural concrete of continuous slabs. The use of the method makes it possible to determine the fire resistance of an uncut reinforced concrete slab of a girderless ceiling of a building without full-scale fire exposure, increases the reliability of statistical quality control and non-destructive testing, reduces economic costs.

Internal septa of the maxillary sinus and their significance in the planning of endodontic interventions, sinus lifting and dental implantation using a collagen matrix scaffold

INTRODUCTION. The study of the structure of the septa in the area of the maxillary sinus floor is important when planning implantation and sinus lifting operations. The height, number and location of the septa can affect the course of the sinus lifting operation. The aim is to study the structure of the maxillary sinus septa, their height, size, localization in order to prevent complications during surgical interventions.MATERIAL AND METHODS. The article analyzes CBCT data from 444 patients for the presence of septa in the area of the lower wall of the maxillary sinus. The subjects were divided into two groups: with the presence of premolars and molars (288 CBCT) and with the absence of at least one chewing tooth (156 CBCT). A study of 48 passportized skulls was conducted, the anterior wall of the maxillary sinus was sawed out, the structure of the sinus floor and septa was studied in detail. The ratio of the volume of compact and spongy bone substance in the premolar and molar areas was also measured.RESULTS. The obtained research data allowed us to obtain new information about the number of septa in the case of a complete dentition and partial tooth loss. Due to changes in the processes of sinus pneumatization, the number of septa increases with partial tooth loss. Their presence increases the risk of perforation of the Schneiderian membrane during sinus lift surgery, including the use of scaffolds based on a collagen matrix. However, when installing an implant in the base of the septum, its stability can be ensured, since the septa are some kind of buttresses of the maxillary bone. The ratio of the volume of spongy and compact bone substance in the premolar and molar area changes with age.CONCLUSION. The study found that the presence of coronal septa can cause complications of sinus lift surgery in the form of perforation of the Schneiderian membrane. At the same time, septa, being buttresses of the maxillary bone, can serve as a basis for installing an implant. With partial loss of teeth, the number of coronal septa increases. With age, the ratio of spongy and compact bone substance changes, towards a decrease in the volume of trabecular and an increase in the volume of compact bone.

Conservation of Waterlogged Wooden Structures from the Late Bronze Age at İnönü Cave (Türkiye)

ABSTRACT During the excavations carried out in the İnönü Cave, located within the Western Black Sea region of Türkiye, four separate floor structures made of wood, dating back to the Late Bronze Age (1436-1123 Cal BCE), were unearthed. The way the corners of the structures are connected shows that the structures were built with the çantı or bell technique, a traditional nail-less wooden architectural form of the Black Sea region. Thanks to the wet and stable environmental conditions within the cave, the wooden floors have survived and are well preserved from the Late Bronze Age to the present day. This study presents the details of the conservation practices developed and deployed in order to ensure that the wooden floors are well protected and remain available for study in the short and medium term.

A machine learning framework for seismic risk assessment of industrial equipment

The paper aims to propose a novel machine learning framework for seismic risk assessment of industrial facilities. In this respect, a compound artificial neural network model is employed, which is based on two different artificial neural network models in series. The first artificial neural network is a regression model employed to generate samples of a vector-valued intensity measure. The second one is a classification model that is used to predict structural damage, starting from the outcomes of the first artificial neural network model. The datasets used for training and validation of the two artificial neural networks are based on hazard-consistent accelerograms and numerical analyses that are performed with an efficient finite element model of the structure. The methodology entails a preliminary feature selection phase for the identification of the aforementioned vector-valued of intensity measures that better classifies the damage/no-damage condition of the structure. This phase is implemented through the principal component analysis method. Subsequently, the Metropolis–Hastings algorithm is used to generate samples of a selected intensity measure, feeding the first ANN model. In turn, the chosen features are used as input parameters of the second ANN model to generate samples of damage/no-damage events. Using the two ANN in series, the mean annual frequency of exceeding a specific limit state is derived. The proposed framework is validated using a typical multi-storey steel frame, focusing on the seismic risk assessment of a vertical storage tank located at the first floor of the primary structure. The proposed method exhibits some clear advantages of combining numerical models with ANN techniques, mainly related to: a reduced computational time; the avoidance of any prior information on the probabilistic model of fragility curves; and the use of model-driven data.

Biofeedback efficacy for outlet dysfunction constipation: Clinical outcomes and predictors of response by a limited approach.

Functional defecation disorders (FDD) are a common etiology of refractory chronic constipation (CC). FDD diagnosis (dyssynergic defecation [DD] and inadequate defecatory propulsion [IDP]), requires diagnostic tests including anorectal manometry (ARM) and balloon expulsion test (BET). Biofeedback (BF) is the treatment of choice for DD. The aims of our study were to evaluate: the outcome of BF in a group of constipated patients with defecatory disorders of any etiology; the efficacy of two simple diagnostic tools in predicting BF outcome in the short-term. One hundred and thirty-one refractory CC patients failing the BET underwent BF therapy. Before BF, all patients underwent the following: ARM. Straining questionnaire. The answers were: "belly muscles"; "anal muscles"; "both"; "Don't know/No answer." Digital rectal examination augmented by abdominal palpation on straining (augmented-DRE). The BF therapist was blinded to ARM, straining questionnaire, and augmented-DRE results. Eighty-one patients responded to BF. Gender, age, and IBS-C showed no significant impact on BF response. Both DD and IDP responded equally to BF, while the rate of response in patients with isolated structural pelvic floor abnormalities was lower (p < 0.001). The answer "anal muscles" to straining questionnaire showed a strong association with BF response (p < 0.001). A lack in abdominal contraction and in anal relaxation on augmented-DRE were strongly associated with BF response (p < 0.01). Absence of manual maneuvers to facilitate defecation was associated with BF response (p < 0.001). BF is the therapy of choice for refractory constipation due to FDD of any etiology, inducing both clinical and anorectal physiology improvement in the short term. Comorbid IBS-C did not affect outcome while symptomatic isolated pelvic floor abnormalities appeared refractory to behavior treatment. The straining questionnaire and augmented-DRE outcomes showed a strong correlation with BF response and can be implemented in clinical practice to improve the management of constipated patients by prompting early referral to BF.

Shaking table test and numerical simulation of rocking wall frame structure considering dynamic soil-structure interaction

This study investigates the seismic response of a rocking wall frame structure considering dynamic soil-structure interaction (DSSI) through shaking table tests. A comparison with conventional frame structures and structures with fixed-base foundations is made to examine the influence of DSSI effects on various aspects including structural damage distribution, dynamic characteristics, and floor responses. Test results indicate that the presence of a rocking wall reduces structural responses across different site conditions, although the reduction is less significant under soft soil conditions compared to fixed-base foundation conditions. Overall, DSSI diminishes the mitigating effect of the rocking wall on the maximum structural response. Furthermore, a three-dimensional finite element model of the shaking table test is established. The numerical model employs the equivalent linear method to simulate the soil's nonlinear behavior and incorporates the concept of the rocking wall. Comparative analysis between experimental and simulated results demonstrates that the model effectively predicts the dynamic response of the rocking wall frame structure in DSSI systems.

Seismic isolation design of high-rise shear wall structures in high-intensity areas

Taking a shear wall structure in a high-intensity area of 20 floors as an example, the seismic reduction scheme of the structure was determined, and the Etabs software was used to conduct time history analysis on the seismic and non-seismic structures. The floor shear force, overturning moment, and short-term surface pressure of the isolation support were obtained. The results showed that under frequent earthquake action, the average maximum floor shear force in the X direction of the isolated upper structure was only about 28 % of that of the non-isolated structure. The maximum inter story shear ratio was 0.34, and the maximum floor shear force in the Y direction was only about 25 % of that of the non-isolated structure. The maximum inter story shear ratio was 0.31. The average maximum overturning moment of the upper structure in the X direction after isolation is about 30 % of that of the non-isolated structure. The maximum overturning moment ratio is 0.36, and the average overturning moment of the maximum floor in the Y direction is about 22 % of that of the non-isolated structure. The maximum overturning moment ratio is 0.26. Under rare earthquake action, the maximum inter story displacement angles in the X and Y directions of each floor of the seismic isolation structure are 1/302 and 1/446, respectively. The maximum surface pressure value of the isolation bearing under rare earthquake is 28.9 MPa, the minimum surface pressure value is 5.58 MPa, and the maximum displacement is 579 mm, which meets the requirements of the specifications. Overall, the seismic performance of the seismic isolation structure is good, and the isolation scheme is feasible.

The effect of stacking sequences on energy absorption in axial crushing of CFRP stanchions for the cargo floor structure of airplanes

One of the remaining challenges for advancing the wide application of composite materials is to further improve the mechanical properties of composites. The fiber/matrix damage phenomenon produced by the composite model under axial loading has been observed through the establishment of a numerical model of composite damage. Axial crush tests have been performed on C-type carbon fiber reinforced polymers (CFRP) stanchions for the cargo floor structure of transport category airplanes using a finite element approach. The failure morphology and crashworthiness parameters of the specimens with different fiber layups have been recorded, and the effects of fiber orientation and angle of entrapment on the crashworthiness of the composites have been investigated. The present study demonstrates that the crashworthiness of composites can be effectively improved by fiber orientation design. Appropriate addition of 45° layer and 90° layer can effectively improve the crashworthiness of C-type CFRP laminates, and the performance of the two-angle and spiral laminates design is improved by 26% and 19%, respectively.

Reduction in Floor Impact Noise Using Resilient Pads Composed of Machining Scraps.

Floor impact noise is a significant social concern to secure a quiescent living space for multi-story building residents in South Korea. The floating floor, consisting of a concrete structure on resilient pads, is a specifically designed system to minimize noise transmission. This floating structure employs polymeric pads as the resilient materials. In this study, we investigated the utilization of helically shaped machining scraps as a resilient material for an alternative approach to floor noise reduction. The dynamic elastic modulus and loss factor of the scrap pads were measured using the vibration test method. The scrap pads exhibited a low dynamic elastic modulus and a high loss factor compared to the polymeric pads. Heavyweight impact sound experiments in an actual building were conducted to evaluate the noise reduction performance. The proposed pads showed excellent performance on the reduction in the structure-borne vibration of the concrete slab and resulting sound generation. The analytical model was used to simulate the response of the floating floor structure, enabling a parametric study to examine the effects of the resilient layer viscoelastic properties. Both experimental and analytical evidence confirmed that the proposed scrap pads contribute to the development of sustainable solutions for the minimization of floor impact noise.

Clinical value of transperineal ultrasound in evaluating the effects of different delivery methods on the primipara pelvic floor structure and function

To evaluate the effects of different delivery methods on the pelvic floor structure and function among primiparas by transperineal ultrasound, with a view to providing guidance for early postpartum intervention. Primiparas who underwent postpartum examination with transperineal ultrasound were recruited. Subjects were divided according to mode of delivery (vaginal and cesarean delivery). General information (including age, pre-pregnancy BMI and neonatal weight) were collected, and transperineal ultrasound was performed to measure such indicators as the levator hiatus areas in resting, constrictive anal and maximum Valsalva states, the posterior vesicourethral angles and distances between vesical neck and posterior inferior margin of pubic symphysis in resting and maximum Valsalva states, as well as the vesical neck mobility and urethral rotation angle in maximum Valsalva state. The inter-group differences in ultrasound indicators between the resting and Valsalva states were compared to analyze the postpartum incidences of pelvic floor dysfunctions like stress urinary incontinence, urethral funnel formation, bladder prolapse and uterine prolapse in primiparas. The levator hiatus areas in resting, constrictive anal and maximum Valsalva states were all larger in the vaginal delivery group than in the cesarean delivery group (P < 0.05). Compared to the cesarean delivery group, the vaginal delivery group exhibited larger posterior vesicourethral angles in resting and maximum Valsalva states (P < 0.05). The distances between vesical neck and posterior inferior margin of pubic symphysis were greater in the cesarean delivery group than in the vaginal delivery group at both resting and maximum Valsalva, with that at maximum Valsalva showing significant inter-group difference (P < 0.05). The vaginal delivery group exhibited greater vesical neck mobility and urethral rotation angle at maximum Valsalva compared to the cesarean delivery group (P < 0.05). The incidences of stress urinary incontinence, urethral funnel formation, bladder prolapse and uterine prolapse were all higher in the vaginal delivery group than in the cesarean delivery group, with the stress urinary incontinence and bladder prolapse incidences showing significant inter-group differences (P < 0.05). With transperineal ultrasound, various pelvic floor indicators of primiparas can be clearly measured and, through these ultrasound indicators, the effects of different delivery methods on the pelvic floor function can be evaluated, which is conducive to early clinical detection and intervention of postpartum pelvic floor dysfunctions, thus facilitating the early postpartum treatment.

Study of the Micro-Vibration Response and Related Vibration Isolation of Complex Traffic Load-Induced Experimental Buildings

In view of the high-sensitivity vibration effect of precision instrument laboratory buildings under the influence of surrounding traffic loads, field micro-vibration tests under various working conditions were carried out based on actual projects. Combined with numerical simulation, measured data served as input loads to simulate the vibration effect of various traffic loads on the floor of a building structure, and the structural vibration laws under the comprehensive action of various loads were analyzed. The vibration isolation effect of the isolation ditch on the oblique orthogonal load was investigated according to the corresponding safety index. The results show that the main frequency components of the site vibration frequency caused by various traffic loads are approximately 25 Hz and that the root-mean-square speed value is stable below VC-E, which meets the design requirements. Under the comprehensive action of multiple loads, the site structure will produce a vibration amplification effect, which is obvious when all types of loads are distributed symmetrically and the curve distribution is controlled by load factors with large amplitudes. The isolation effect of a small isolation ditch is best when it is located close to the source and the building. The depth of the isolation ditch must be greater than the maximum depth of the source to achieve better results, and the width has little influence. The effect of a small isolation trench on vertical vibration is poor, and the oblique orthogonal triaxial load has a counteracting effect on the vertical component. Thus, additional structural vibration isolation measures are needed. The research results provide a reference for engineering vibration isolation, damping measures, and structural design.

Pelvic floor status during pregnancy as a predictor of pelvic dysfunction and birth outcome

This literature review presents an analysis of a number of studies that examined the association between pelvic floor health during pregnancy and the development of pelvic dysfunction and birth outcomes. These studies consistently demonstrated that changes in pelvic floor structure and function during pregnancy are associated with an increased risk of developing pelvic disorders such as urinary incontinence and pelvic organ prolapse. Besides, certain pelvic floor characteristics, such as muscle strength, tone, and stretching ability, have been identified as potential predictors of pelvic floor dysfunction during pregnancy and prolonged second-stage labor. The data collected suggest that pelvic floor assessment during pregnancy may provide valuable prognostic information about birth outcomes. Understanding these relationships may lead to improved prenatal care strategies and interventions to optimize pelvic floor function and reduce the incidence of adverse birth outcomes. Further research is required to clarify the specific parameters for evaluating pelvic floor changes that are most indicative of pelvic organ dysfunction and adverse birth outcomes, as well as to assess the efficacy of preventive interventions.

Fitness club adjacent to a quiet corporate office - Prototypes

There is a demand for fitness clubs in hotels, residential, and corporate buildings - sometimes adjacent to sensitive spaces. Activities involving weight drops and spinning bikes, among others, cause dynamic forces in the structure that propagate through the building's structure and radiate airborne sound. There is an effort by acousticians worldwide to establish a standardized method for measuring and rating the noise radiated by gyms into adjacent areas. This article describes the construction of a gym over a corporate office, occupying an area of 2100 m2 each. The gym's floor structure is a concrete and steel deck, and the office below has low sound levels. The goal of making gym activity inaudible in the office is undoable in practice. We tested several prototypes to arrive at a double insulation system with a floating slab with natural rubber mounts. A system of dynamic dampers was installed to reduce the movement of the floating slab with the dynamic excitation above it. The results of the prototype were auspicious. This paper presents the measurements of the natural frequency of the structure and the floating slab, the transmissibility of the system, and the differences in vibratory velocity from the floating floor to the structure.

Weight minimization of train floors with acoustic and structural constraints

For high-speed trains, high noise levels are generated in the bogie from wheel-rail contact and aero-acoustic sources. Manufacturers try to minimize the floor transmission to the interior, e.g. by applying damping layers or by other measures. For vehicle noise control measures, the goal is often to achieve the sound reduction needed at lowest possible mass. Here, an optimization scheme is applied to minimize the mass of an extruded floor panel. Constraints are defined by limiting the maximum local floor deflection from passenger loads according to EN 12663-1 and the A-weighted interior sound level. Recognizing the periodic nature of the floor structure, a Finite Element model of a single periodic cell is set up, using periodic boundary conditions and the floor sound reduction is determined using a Statistical Energy Analysis approach. An analytic beam model is applied to determine the floor deflection from the passenger load. Design solutions meeting the constraints with the smallest possible mass are sought. Starting with a floor structure with 23.3 kg/m2, a final design with 18.0 kg/m2 is reached. In addition, the transmitted sound through the floor is reduced by 8 dBA. Convergence from different starting points is verified.

Experimental investigation of the sound absorption characteristics of unconsolidated granular materials

In the context of a wider research project investigating the use of Granular Material (GM) within floor and wall structures to increase their sound insulation, this study presents the sound absorption coefficient (SAC) measurements of different thicknesses for a range of GM. A primary aim has been to extend the understanding of the behaviour of GM layers in absorbing the propagated incident sound wave. Equally important has been an assessment of what GM could be sourced from waste and be acceptable for use in buildings from the point of view of fire insulation, handleability, economy, etc. Samples of GM were placed in an 88mm diameter vertical impedance tube and SACs measured up to 2kHz. The results show the effect GM's different structure (size and shape), bulk volume, and mechanical characteristics have on the range and value of the SAC. These determine the extent to which GM could be a replacement for traditional sound absorption materials.

Comparative analysis of the heavy-weight floor impact noises using different types of EVA resilient materials

The present study aims to improve the floor impact noises using various shapes of EVA resilient materials in composite floor structures. In order to this, three different types of EVA resilient materials were used including flat plate, deck plate type and cavity type of EVA boards. All the composite structure consisted of PP panel, PET and EVA resilient materials with a total depth from 30mm to 40mm. Total of 9 specimens were made for floor impact sound measurements. All the floor impact sound measurements were done at the recognized testing authority using bang machine. The values of L'I,Fmax,AW were deduced from every measurements. As a result, among the various types EVA resilient materials, most high performances were drawn when cavity type of EVA resilient material was used. It was shown that the average L'I,Fmax,AW value of cavity type was 46dB while 47dB for deck plate type, 48dB for flat plate were measured in average. It can be recognized that the good performance of cavity type EVA materials is caused by the both air layer gap beneath EVA board and air cavity inside the EVA board as well as the low dynamic elastic modulus of EVA.

Comparative study of different programs for sound insulation calculations

Engineering programs for calculating sound insulation in wooden buildings are a shortage, especially when it comes to wooden structures. There are some possibilities today to calculate field values using commercial programs following ISO 12354. However, detailed calculations for each construction part are sometimes crucial to optimize correctly, specifically for CLT or wood beam structures since they are far more complex than traditional concrete structures. Now, some programs are available on the market to calculate sound insulation for CLT structures. StoraEnso offers "Calculatis" online for free, and Marshall Day Acoustics provides "Insul 10". In short, the company Sonusoft will release a software called "Acoulatis". These three programs have slightly different approaches, and their capability to calculate various wall and floor structures differs. Nevertheless, the different programs are all limited to walls or floors construction parts, e.g. the outcome is Rw and Ln,w including spectrum adaptation terms, e.g. junctions are not included. In this paper, a comparison is made using the three different programs, including comparisons to measured values when available.

Impact sound insulation performance of floor coverings in a heavyweight reference floor with a floating floor

This study investigates the impact sound reduction performance of floor coverings used on the heavyweight standard floor of a floating floor structure in comparison with bare slab testbeds through on-site experiments. The laboratory performance evaluation of floor coverings designates only a bare slab between 100 mm and 160 mm as the heavyweight reference floor according to Annex C in ISO 10140-5. However, the recent expansion of over-floor heating systems has led to an increased need for understanding the impact sound reduction performance of floor coverings on floating floors, to enhance occupants' thermal comfort. In this study, it was measured the heavyweight and lightweight floor impact sound reduction levels of various floor covering test specimens in testbeds with different thicknesses of bare slabs and actual apartment houses with floating floors applied. The reduction rate for each frequency band was determined before and after installing floor coverings including single number quantity in accordance with ISO 717-2. Additionally, the impact of heavyweight reference floor conditions on quantifying the sound performance of floor coverings was discussed.

Inelastic acceleration ratios for nonstructural components

Non-Structural Components (NSCs) include all the elements that are part of structures but are not typically designed to resist the loads acting on the structures. In recent major earthquakes, the seismic design of NSCs has proved to be a key feature to assure suitable performance of structures. The accelerations experienced on the floors of structures are much higher than those at ground level, and therefore, NSCs located at these levels are highly susceptible to experiencing inelastic responses. However, relatively few studies have investigated the inelastic response of NSCs. Specifically, the inelastic absolute acceleration ratio (IAR) of NSCs is an important inelastic design parameter that has been the subject of little investigation. Therefore, this research aims to investigate the inelastic response of NSCs through its IARs by using seven elastic buildings of three different structural systems and three different sets of far-field seismic ground records. The inelastic response of the NSC is characterized by the yield strength reduction coefficient (R). The results of the study were used to develop an equation for estimating the characteristic period of ground IARs. In general, the characteristic period is equal to the fundamental period of the structure for the floor IARs and floor Inelastic Displacement Ratios (IDRs). In addition, the results helped to identify that the convergence values of the IARs mainly depend on the R factor and the damping ratio of the NSC and show consistency in both the ground IARs and the floor IARs. Furthermore, the trends of the floor IDRs are more unstable and less predictable than those of the IARs. An improved equation for predicting both ground and floor IARs is also proposed.

A novel pelvic magnetic resonance imaging measurement for pelvic organ prolapse evaluation

BackgroundPelvic magnetic resonance imaging has been proven effective for quantifying the extent of prolapse. The pubococcygeal line is used universally as a reference line in measuring pelvic organ prolapse, however, it focuses solely on three lowest points in the anterior, middle, and posterior pelvic compartments, without taking into account other pelvic floor structures and their interactions. ObjectivesThis study aimed to introduce and validate the area under the pubococcygeal line, a novel measurement method for evaluating pelvic organ prolapse, to examine its correlation with clinical Pelvic Organ Prolapse Quantification staging, and assess its reliability across different raters. Study DesignThis study recruited 225 women who underwent evaluations involving both magnetic resonance imaging measurements and clinical Pelvic Organ Prolapse Quantification staging. A comprehensive statistical approach involving descriptive analysis, correlation analysis, reliability assessment, and ordinal logistic regression analysis was adopted to evaluate the applicability and reliability of the area under the pubococcygeal line measurement. ResultsAnalysis of participant characteristics across different POP-Q stages revealed a significant association between increased values of the area under the pubococcygeal line and severity of Pelvic Organ Prolapse Quantification staging. Correlation analysis was performed to identify and quantify the strength of the associations between the variables. The area under the pubococcygeal line showed a strong positive correlation with Pelvic Organ Prolapse Quantification stages (Spearman's r = 0.878, p < 0.001), outperforming the pubococcygeal line grades (Spearman's r = 0.777, p < 0.001). Reliability assessments yielded excellent intra- and inter-rater reliability, with intraclass correlation coefficient values of 0.980 and 0.906, respectively. Ordinal logistic regression analysis was used to determine the association between these variables and POP severity, highlighting significant associations between the area under the pubococcygeal line and Pelvic Organ Prolapse Quantification stages. ConclusionThe area under the pubococcygeal line measurement method is a novel and comprehensive magnetic resonance imaging technique for evaluating pelvic organ prolapse. This method strongly correlates with clinical Pelvic Organ Prolapse Quantification stages and exhibits excellent intra- and inter-rater reliability, holding a potential for enhanced diagnostic accuracy, optimized treatment strategies, and improved patient outcomes.