Floor System Research Articles

Optimization of CO2 Emission of the Composite Floor System via Metaheuristics Algorithm

Optimization of CO2 Emission of the Composite Floor System via Metaheuristics Algorithm

Optimum design of a composite floor system considering environmental and economic impacts

Abstract The composite floor system, composed of steel deck and concrete slab, generates more efficient and economical structures. On the other hand, the design of this type of structure has a high complexity level due to the consideration of several variables. In this respect, the objective of this paper is to present the formulation of the optimization problem for a composite floor system (steel and concrete) considering such environmental as economic impacts. To formulate the optimization problem, the reduction of environmental impact was adopted as an objective function - assuming the CO2 emission and the finance cost as parameters. The restrictions were taken by the limiting states imposed in standard NBR 8800:2008. The computer program was developed via Matlab R2016a and the optimization process was carried out using the Genetic Algorithm toolbox existing in this platform. Two application examples of the formulation at hand are presented: the first from the literature and the second from an existing building - in both situations the influences of different concrete compressive characteristic strengths were analyzed. The results of the optimization problem show a reduction in geometry and, consequently, in its weight. The solution found by the program reduces by up to 17.70% of CO2 emissions and 17.47% of the finance cost. When was applying different concrete compressive strengths, the optimal solution for environmental impact did not get the lowest cost. In general, the steel deck formwork obtained the highest percentage of environmental impact, while the beams and girders, with the same shape configuration, had the highest finance cost. Therefore, it is shown that the optimal design solution to CO2 emissions is not always the better solution for the finance cost.

Finite element analysis of RC beams with and without openings

In this research article, the finite element analysis of RC beams has been analyzed using the ABAQUS program. FEA was performed to investigate the flexural behavior of the beams with various structural configurations. The non-linear finite element method was also used to study the structural behavior. The study of the design of reinforced concrete beams with and without opening will help to pass service ducts and MEP lines through the structural zone of floor systems. The purpose of this research study is to reduce the beams self-weight as well as the overall structure. The main parameters of the paper are the presence of the main bar, the size of openings, the position of openings, and the types of openings. The specimens taken for these analytical studies are 9 sets of squares, circular and hexagonal opening beams each provided with a steel pipe at the opening. The openings at the beams are placed at the length of l/4, l/3, and l/2m for every set of beams. The size of the openings is 50 mm and 75 mm. The static loading behavior of the beam was obtained using ABAQUS. Analytical results of the beams with and without openings of various sizes and locations were compared. It was found that plastic hinges and shear cracks can be reduced by providing the opening with steel pipes on the beams.

Investigations on geometrical modifications for profiled decking of composite slabs

Steel – concrete composite slabs are used in the construction of floor decks in composite structures. The benefit of composite element is that the properties of each material can be combined to form a single unit that can perform better than its constituent parts. Thus, the composite construction makes use of the benefits of both steel and concrete. Composite decking works together with the concrete fill to make a stiff, light weight economical floor system. It provides bond between the steel and concrete. If used, it stabilizes the building as a whole by acting as a diaphragm to transfer wind loads to the walls and columns. Steel decking stabilizes beams against lateral torsional buckling during construction. This paper discusses about the strengthening technique of profiled decking, evaluating the results in terms of load carrying capacity, stiffness and deflection by numerical analysis. The numerical analysis is done using commercially available software. Experimental investigations are also carried out to study the performance of strengthened composite slab as floor slabs. Results show that stiffened composite slabs with clamped support improves the slab performance by controlling deflection.

Performance analysis of the different radiant floor cooling systems in the office building in Shandong province, China

Radiant cooling systems have good application prospects. A variety of composite radiative cooling systems have been proposed to save energy, but few studies have focused on comparing the performance of different radiant floor cooling systems. This study compares the cooling performance operating conditions of a floor radiant system with direct ground cooling and conventional radiant cooling systems. In addition to the comfort conditions required by the standard, Jinan, Shandong also studied the low risk of condensation on the floor surface. At the same time, the energy consumption of different radiative cooling systems is compared and the potential of the system is analyzed. Preliminary results found a 26% reduction in energy consumption for system operation compared to conventional radiant cooling systems. Although the radiant floor system using the ground direct cooling system does not reduce energy consumption when the water tank is turned on for energy storage at night, the electricity cost is reduced due to the peak and valley electricity price at night. The research will provide architects and engineers with more efficient and energy-efficient technologies that reduce carbon emission.

Experimental Study On Operating Characteristic For Combined Radiant Floor And Fan Coil Cooling System In Under Low Temperature And High Humidity

The combined radiant floor and fan coil cooling (RFCAFC) system is widely used due to its high comfort and large energy saving potential. In this study, as an example, the combined RFCAFC system was studied in a high humidity environment in Jinan, Shandong Province, China. Days with similar outdoor meteorological conditions were grouped, and the comfort level and other evaluation indicators. The RFCAFC had good energy efficiency and comfort when the room was in a high humidity environment. This study showed that the radiant floor surface temperature uniformity coefficient (S) fluctuated between 0.7 and 1.0. The proportion of the total cooling capacity contributed by fan coil cooling under low temperature and high humidity (LH) is 68.0%. The combined cooling system used the LH operating strategy, the PMV value fluctuated from 0.12 to 0.49. Based on this study, the following recommendations for the combined cooling system can be made: (1) When the outdoor humidity is high, the radiant floor system should be turned on early to provide cooling capacity. (2) The operation strategy of the combined cooling system must be able to respond in real time to changes in outdoor meteorological conditions to prevent discomfort in times of extreme heat or humidity.

SURVEILLANCE OF BLOOD PARASITES OF NATURALLY-GROWN SMALL RUMINANTS IN SELECTED PROVINCE OF REGION 02

This study aimed to determine the epidemiology and surveillance of blood parasites of naturally-grown small ruminants in selected province of Region 02. Descriptive method through a survey questionnaire and a blood parasite examination was employed. Survey showed that, there were 23 naturally-grown small ruminant farms located at Districts II and III in Cagayan province. Anaplasma spp. and Babesia spp. were the species of blood parasite identified. Test of difference showed that presence of blood parasites was significant with sex of the naturally-grown small ruminants and between Districts. Further, test of relationship showed that types of housing, fence, floor, breeding, and feeding system were significant of the naturally - grown small ruminant farms. Thus, it concludes that the type of management practiced by the farmers results in the present of blood parasite.

Mortise-and-tenon joinery for modern timber construction: Quantifying the embodied carbon of an alternative structural connection

The mass timber industry offers a compelling pathway for low-carbon structural systems in buildings, replacing carbon-intensive materials like concrete and steel with sustainably forested wood. However, conventional structural connections in mass timber construction are largely made of metallic materials, such as screws, nails, and plates. In contrast, joinery, or geometrically interlocking all-timber connections, is globally prevalent in historic timber construction. This paper investigates the potential of applying joinery, specifically the “Nuki” mortise-and-tenon joinery connection, to contemporary mass timber construction from perspectives of structural behavior and carbon savings. Considering single spans supporting one-way cross-laminated timber (CLT) floor systems at the mid-rise residential scale, carbon savings ranging from 7 to 40% are possible at the beam-joint scale by using Nuki joints instead of steel concealed beam hangers, a more conventional mass timber connection. While these savings are smaller at the building scale, the paper nevertheless demonstrates a methodology and results for quantitatively comparing the scale of savings achieved by implementing this historic but contemporarily alternative connection type.

Prevalence of non-infectious claw disorders in Egyptian dairy farms in relation to the flooring system

Lameness is one of the most prevalent and costly maladies affecting dairy cattle. It has been ranked as the third after mastitis and reproductive failure. One of the leading causes of lameness is corium tissue damage and hence claw horn lesions development. Flooring system was found to have an impact on the development of such lesions. Therefore, the objective of the present study was to study the effect of flooring system on the development of four non-infectious claw disorders in Egyptian dairy farms. Another objective was to study the effect of claw disorders on reproductive performance and total milk production. Four dairy herds with earthen floor (n=2) and desert floor (n=2) from Ash-Sharkia and Ismailia Provinces were included in this study. Results revealed that the prevalence of white line disease (WLD) was the highest among recorded lesions in earthen floor farms (2.7%) followed by sole ulcer (SU) 2.1% and sole abscess (SA) 1.7% then vertical wall fissures (VWF) 1.6%. While in the desert floor farms, VWF and SA were reported in 0.8% of animals followed by WLD and SU in 0.4% and 0.3% of animals, respectively. The non-infectious claw disorders were detected mainly in hindlimbs in earthen floor farms when compared to forelimbs (6.6% and 1.5%, respectively) while in the desert floor farms were nearly equal for the forelimbs (1.1%) and hindlimbs (1.2%). In conclusion, the animals housed in earthen floor farms were more susceptible to non-infectious claw disorders than those housed in desert floor.

Efficiency of prestressed concrete joist reinforced by CFRP: Experimentation and analytical verification

AbstractIn this paper, the bending behavior of prestressed concrete joists strengthened by fiber‐reinforced polymer (FRP) laminates is described. An experimental investigation on 18 large‐scale beams is conducted, allowing determination of the strengthening influence of FRP in the general behavior of prestressed joists. The mechanical parameters considered in the study are the ultimate and elastics loads and the deflection or initial stiffness of joists. The analytical verification is done to calculate the design load values of the floor system. The results indicate that the application of FRP laminates significantly increases the response of prestressed concrete joists.

Rational horizontal tying force method for practical robustness design of building structures

This paper presents a rational method for the horizontal tying of multi-storey building structures aimed at robustness design and the mitigation of progressive collapse. Unlike current prescriptive tying force approaches, the new method benefits from i) a rational association with local damage scenarios consisting of the sudden loss of a column or a load-bearing wall, ii) the explicit consideration of the system ductility limit and dynamic amplification, iii) the systematic combination of various types of loading and sources of tying, and iv) supplementary methods for assessing the interaction of the affected floor system with the surrounding structure. Importantly, these relative benefits are still realised within a practical application framework that is comparable in simplicity to prescriptive tying rules, making the proposed tying method suitable for codification and as a replacement for prescriptive tying force requirements in the next generation of robustness design codes. Following a detailed exposition of the method formulation and parameters, the paper presents several studies which demonstrate the effectiveness of the proposed tying force method, concluding with an example that illustrates its application to a typical reinforced concrete floor system.

Shear connection of prefabricated ultra-lightweight concrete slab systems (PUSSTM)

This paper reports a detailed computational study of a recently developed novel steel–concrete composite flooring system (PUSS) with two different types of shear connectors: (i) web-welded shear stud connectors (WWSS), and (ii) web-welded shear stud with dowels (WWSS with dowels). In addition, different types of concrete, (normal and lightweight,) are used. A nonlinear FE model is developed and validated against two sets of full-scale push-out tests of the novel steel–concrete composite flooring system reported in a companion paper. The FE model replicated the experimentally determined failure loads, ultimate slips, and observed failure modes. Parametric studies are conducted to obtain the failure loads and ultimate slips of these PUSS untis with different types of concrete: normal weight concrete, light weight concrete and ultra light weight concrete (NWC, LWC and ULWC), and various diameters and heights of shear connectors (WWSS, WWSS with dowels). The concrete strength varied between 20 N/mm2 to 35 N/mm2, the shear connectors’ diameter varied between 16 mm, 19 mm, 20 mm and 22 mm, and the height of the shear studs between 75 mm and 100 mm. In conclusion, load-slip curves obtained from the FE parametric studies demonstrated that FE models with same diameter of shear connectors can result to different slip stiffnesses, while the failure loads and slips varied with the concrete strengths. The slip results were also compared with different shear connection systems’ dimensions at concrete strengths of 20, 30 and 35 N/mm2.

Assessment of the Pelvic Floor and Associated Musculoskeletal System: Guide for Medical Practitioners.

This study aimed to assist practitioners in performing an accurate assessment of the external and internal pelvic musculoskeletal (MSK) systems to improve appropriate diagnosis and referral of patients with pelvic floor disorders or pelvic pain and to improve understanding of physical therapy (PT) treatment principles, thereby improving communication between practitioners and encouraging a multidisciplinary approach. A referenced review of the anatomy of the pelvic floor muscles, pelvis, and surrounding structures, followed by a detailed assessment of anatomy, posture, and gait, is presented. A thorough description of PT assessment and treatment is included with clinical relevance. When proper assessments are routinely performed, MSK conditions can be recognized, allowing for prompt and appropriate referrals to PT. Assessment and treatment by qualified physical therapists are integral to pelvic health care. After efficient medical assessment, MSK dysfunction can be addressed expeditiously, thereby avoiding further decline. Left unaddressed, pelvic dysfunction may become chronic. We propose a guide for MSK assessment of the pelvis and associated structures that can be used for both clinical and research purposes. This guide is designed for health care providers caring for women with pelvic floor disorders, including physicians, advanced practice providers, and nurses. This guide serves to improve communication among multidisciplinary practitioners to refine MSK assessment and treatment approaches and thereby advance clinical care and research.

Hybrid posttensioned rocking (HPR) frame buildings: Low-damage vs low-loss paradox

The 2010-11 Canterbury Earthquake Sequence inflicted seismic losses worth more than $40B, which is about 25% of the GDP of New Zealand (as per 2011 data). More than 80% of these losses were insured, which comprised of more than $10B covered by the Earthquake Commission (a New Zealand crown entity providing insurance to residential property owners) and more than $22B (comprising of roughly equal split between domestic and commercial claims) by private insurers [1]. The scale of financial impact has been perceived to be disproportionately large given the building regulatory regime in New Zealand is relatively stringent and the earthquakes and aftershocks were of moderate magnitude. As it is well known that some of the major faults spread in the Wellington region and the subduction boundary passing through the centre of New Zealand can generate much bigger earthquakes (upwards of magnitude 8), people are left pondering whether New Zealand is able to cope with the financial impact of larger earthquakes. This fearful realisation gradually led to people being dissatisfied with merely life-safe buildings and demanding more resilient buildings that meet the objectives of performance based design; i.e. suffer less damage, incur less loss, and can remain functional after earthquakes.
 In light of the extensive building damage resulting in high financial loss in recent earthquakes, practicing engineers and researchers in New Zealand have been advocating for revising the current design approach to improve performance of new structures and infrastructure in future earthquakes [2-5]. As a result, large proportion of buildings constructed in the last decade (including those built to replace earthquake-damaged buildings) have shied away from the traditional damage-friendly ductile structural systems and instead adopted one of the new and emerging structural systems claimed to be “low-damage”. In many cases, the adopted structural systems are not covered by existing design standards and are approved as alternate solutions through expert peer review. The “low-damage” attribute of most structural systems has been validated by component (or sub-assembly) level experimental tests, but their interactions with other building components and implications of their use in buildings have not been rigorously scrutinised. Hence, the rushed adoption of some of these systems in buildings can surprise the engineering community in future earthquakes with mismatch between the expected and real performances of the buildings; akin to what New Zealand engineering fraternity is currently going through due to realisation of poor seismic performance of precast hollow-core flooring system that has been widely used in New Zealand buildings without rigorous scrutiny.
 One such “low-damage” structural system is precast post-tensioned rocking frames with supplemental energy dissipaters. This paper summarises the development of this structural system, critically reviews the literature reporting the seismic performance of this system, and qualitatively evaluates system-level implications of its use in buildings. This paper is intended to better inform engineers of the likely seismic performance of buildings with this structural system so that they can optimise its benefits by giving due consideration to its effect on other building components.

Finite Element Modelling for Structural Performance of Slim Floors in Fire and Influence of Protection Materials

Slim floor systems are very common nowadays and various types are currently being used for the construction of high-rise buildings and car parks. Concrete in slim floor beams encases the steel beam section which helps to improve their fire resistance. Despite their higher fire resistance, several fire protection materials like intumescent coatings are often used to achieve a higher fire resistance where desired. The thermal properties and behaviour of various intumescent coating materials were previously studied through experimental investigations. This paper presents finite element analyses to simulate the response of unprotected and protected slim floor beams in fire using different simulation tools. For this purpose, fire tests conducted on unprotected slim floor beams and intumescent coating materials are modelled using research and commercial software. Results from the analyses are compared and verified with the available test data. These validated models are later combined to study the behaviour of protected slim floor beams in fire. Results from the study show that the research and the commercial software replicate the behaviour of slim floor beams and protection materials with good accuracy. Due to the presence of the intumescent coating, the protected slim floor beams displayed a better fire resistance as the temperature of the steel part remained below 400 °C even after 60-min of standard heating. The protected slim floor beams continued to support the external loads even after 120 min of heating.

Effects of Wall-to-Wall Supported Ceilings on Impact Sound Insulation for Use in Residential Buildings

In Korean residential buildings, floor impact sounds were reduced over the past few decades mainly through a floating floor system. However, ceiling constructions for impact sound reduction have not been applied actively because of a lack of useful information. This study focuses on the effects of wall-to-wall supported ceilings (WSC), which are designed with construction discontinuities between concrete slabs and ceilings, and the damping caused by porous absorbers for impact sound insulation. To examine the impact sound insulation according to ceiling conditions, measurements were performed in 25 floor–ceiling assemblies. The results indicate that ceiling treatment is mostly useful in reducing the floor impact sound. The floor impact sound owing to the WSC decreased by 2–7 dB and 2–8 dB in terms of the single number quantity for the tapping machine and rubber balls, respectively, compared with representative existing housing constructions wherein ceilings were attached on wooden sticks. Furthermore, the reduction effect of the WSC appeared to be more profound when it was applied to the floor–ceiling assembly with poor impact sound insulation. Thus, the WSC can be used to enhance the impact of sound insulation of existing housings without major repairs of floor structural layers.

Finite Element Analysis of Dynamic Characteristics and Bending Stiffness for Cross Laminated Timber Floor Panels with and without Openings

The aim of this paper is to present numerical investigations of dynamic characteristics and bending stiffness for cross laminated timber floor panels with and without service openings. Five-layer panels with the outer layers oriented in the longitudinal direction of the panel have been analyzed. In order to explore the full potential of this floor system using a limited number of measurements and structural tests, models based on the finite element method have been proposed, validated against experimental results and then used to investigate the effect of opening position in the floor on main structural performance parameters. The results showed that, when the need for additional service opening appears, a slight decrease of the main structural characteristics of the cross laminated timber floor panels is achievable with an adequate geometrical position of the opening in the floor.

An innovative resource‐efficient timber‐concrete‐composite ceiling system: Feasibility and environmental performance

AbstractTimber‐concrete composite (TCC) ceilings build on the idea of making use of the advantageous properties of both materials symbiotically. While concrete, as the upper layer, is used to absorb the compression forces, wood is used in the lower layer to absorb the tensile forces. Many systems have been developed with special attention paid to solutions with both a continuous concrete and wood layer. This article introduces a new system developed with the primary focus set on the most efficient material use by introducing a free space between the concrete and the wood layer using special vault shaped moldings. The first part of the paper contains an introduction including a short overview of different embodiments of TCC floor systems. The second part focuses on the design of the new system and gives an overview of the estimated structural performance. In the third part the environmental performance of the new system is discussed in comparison to chosen existing systems focusing at the the whole life‐cycle including a re‐use (A‐D).

Mass, Direct Cost and Energy Life-Cycle Cost Optimization of Steel-Concrete Composite Floor Structures

This paper presents a study showing the optimization of the mass, direct (self-manufacturing) costs, and energy life-cycle costs of composite floor structures composed of a reinforced concrete slab and steel I-beams. In a multi-parametric study, mixed-integer non-linear programming (MINLP) optimizations are carried out for different design parameters, such as different loads, spans, concrete and steel classes, welded, IPE and HEA steel profiles, and different energy consumption cases. Different objective functions of the composite structure are defined for optimization, such as mass, direct cost, and energy life-cycle cost objective functions. Moreover, three different energy consumption cases are proposed for the energy life-cycle cost objective: an energy efficient case (50 kWh/m2), an energy inefficient case (100 kWh/m2), and a high energy consumption case (200 kWh/m2). In each optimization, the objective function of the structure is subjected to the design, load, resistance, and deflection (in)equality constraints defined in accordance with Eurocode specifications. The optimal results calculated with different criteria are then compared to obtain competitive composite designs. Comparative diagrams have been developed to determine the competitive spans of composite floor structures with three different types of steel I beam: those made of welded sections and those made of IPE or HEA sections, respectively. The paper also answers the question of how different objective functions affect the amount of the calculated costs and masses of the structures. It has been established that the higher (more wasteful) the energy consumption case is, the lower the obtained masses of the composite floor structures are. In cases with higher energy consumption, the energy life-cycle costs are several times higher than the costs determined in direct cost optimization. At the end of the paper, a recommended optimal design for a composite floor system is presented that has been developed on the multi-parametric energy life-cycle cost optimization, where the energy efficient case is considered. An engineer or researcher can use the recommendations presented here to find a suitable optimal composite structure design for a desired span and uniformly imposed load.

Methods for the vibration analysis of reinforced concrete precast one-way joist slab floor systems under human walking

An assessment of analytical methods for the vibration analysis of reinforced concrete (RC) precast one-way joist slab floor systems under human walking is presented. This study consists of a comparative analysis between analytical, numerical and experimental results. Firstly, an assessment of an existing analytical method for such evaluations is done, since it has not been validated. Subsequently, an efficient finite element model for the vibration analysis of this type of floor system under human walking is proposed. In the experimental program, two slabs specimens were tested under free and forced vibration . One test specimen was done in a laboratory and the other test in an apartment building of confined masonry. Ambient vibration tests were carried out to determine natural frequencies, and forced vibration tests to compute peak accelerations under people walking as induced loads. The experimental results were used as a reference for assessing the analytical and numerical results. It is observed that, in some cases, the analytical procedure underestimates the peak acceleration of the floor systems, while the numerical models yield satisfactory results, which are in agreement with experimental findings. In the assessment of the response of the two specimens with the current serviceability criteria for vertical vibrations, resultant accelerations are greater that permissible acceleration. Consequently, people may experience annoyance and discomfort in this type of floor system under vibrations caused by human walking. • An experimental, analytical and numerical dynamic investigation of two reinforced concrete precast one-way joist slabs with different boundary conditions is developed. • Vibration tests on two reinforced concrete precast one-way joist slabs with two different human-induced excitations are performed. • A practical modelling technique to accurately and efficiently simulate reinforced concrete precast one-way joist slabs under human-induced vibrations is proposed. • An analytical method is evaluated for the analysis of reinforced concrete precast one-way joist slabs under human walking.