Floor Slabs Research Articles

Experimental and Theoretical Studies on the Vibration Serviceability of Composite HCS Floors with RC Topping

Composite hollow–core slab floor with reinforced concrete topping (i.e. CHFT) is relatively new, which can be applied to various long-span structures. However, these systems are typically lightweight and exhibit low damping, posing potential serviceability concerns related to human vibrations. This paper presents a comprehensive vibration test on a 9[Formula: see text]m-long CHFT system. Natural frequencies, damping ratios, and mode shapes of the floor system were obtained through modal tests. The peak acceleration, root–mean–square acceleration, maximum transient vibration value, and perception factor of the floor under heel-drop excitation were obtained through the perceived vibration test and were checked against the available design codes and standards. Sensitivity studies using the finite element method were made to investigate the vibration performance of the CHFT system. Analytical formulas for the fundamental frequency and peak acceleration were derived, which are therefore suggested for practical use. Additionally, an approach for evaluating the vibration serviceability of CHFTs is described.

Simulation and Deformation Analysis of Construction Process of Large Eccentric Frame‐Core Tube Structure

ABSTRACTThe large eccentric frame‐core tube structure may generate nonnegligible horizontal deformation in the eccentric direction during the construction process, which should be given due attention. The construction process of a 388‐m‐high super high‐rise structure was simulated with the effects of concrete properties and construction processes. The reinforcement effect of steel bar in reinforced concrete shear wall and the hoop effect of steel tube in concrete filled steel tube (CFST) columns were considered by using the two‐cell simulation method, respectively. The accuracy of the finite element model was effectively verified based on the measured data under different construction process. The results show that the construction process has a large influence on both the vertical and horizontal deformation. The measures of construction leveling effectively reduce the vertical and horizontal deformation of super high‐rise structures, which is important for controlling the structural deformation. The proportion of creep‐shrinkage deformation in the total deformation is large. In this case, the proportion of creep‐shrinkage deformation in the shear wall is 45% to 50%, whereas it is about 30% in the frame columns. The eccentricity caused by floor slab gravity will be mitigated if the construction of the frame slab lags behind the construction of the steel frame, which is beneficial to the control of the horizontal structural deformation. After construction completion, the deformation caused by nonload factors is limited compared to the deformation caused by live loads.

The failure of partition walls resulted from excessive deflection of the prestressed ribbed floor slab

The failure of partition walls resulted from excessive deflection of the prestressed ribbed floor slab

Study on the structural behavior and reinforcement design of openings in subway station floor slabs

This paper investigates the structural behavior of openings in subway station floor slabs through model experiments and finite element simulation. The study analyzes the effects of the opening's aspect ratio, dimensions, and position on the stress characteristics of various structural components. Based on the stress levels and failure characteristics at different locations in the station structure, three reinforcement schemes are proposed: adding corner fillets, installing buttress columns, and adding ring beams. Comparative analysis with the original structure's internal forces and displacement patterns reveals the effectiveness of each reinforcement scheme. The results show that openings reduce the moment of inertia of the floor slab cross-section, weakening the slab's stiffness and making the area around the openings and slab-column joints prone to local damage. Increasing the aspect ratio of the opening, enlarging its dimensions, or closely arranging multiple openings diagonally reduces the local load-bearing capacity of the structure. Adding corner fillets can reduce the maximum equivalent stress in the slab by more than 15 %, alleviating stress concentration caused by the openings. Buttress columns and ring beams increase the stiffness of the side walls, distribute the lateral forces causing wall bending moments, and enhance the structure's resistance to lateral displacement.

Experimental insights into the seismic behaviour of flanged URM walls

Considerable attention has been given to understanding and modelling the seismic response of unreinforced masonry piers with rectangular cross-sections. However, the seismic performance of load-bearing masonry walls with flanges, commonly found in actual building configurations, remains less explored. This study investigates the behaviour of flanged walls through cyclic quasi-static tests on four full-scale C-shaped specimens comprising two primary seismic-resistant walls (webs) interconnected by a single flange. The construction of the specimens varied: two were built using standard solid calcium-silicate bricks with general-purpose mortar, while the other two utilised large-sized calcium-silicate blocks with tongue-and-groove interlocks and a thin layer of cement-based adhesive mortar. All specimens were subjected to cyclic horizontal loading parallel to the webs under consistent overburden load and double-fixed boundary conditions. The primary variable in testing the two walls of each type was the number of cyclic loading repetitions. This paper initially describes the key characteristics of the wall specimens, including geometry, construction details, and mechanical properties. Subsequently, it details the instrumentation plan and test protocol, and summarises the major observations from the tests, illustrating damage evolution and hysteretic force-displacement response. The results highlight the effect of the flange on initial stiffness and lateral force resistance, as well as the influence of block type and loading repetitions on failure mode, displacement capacity, and energy dissipation. Additionally, the study demonstrates the impact of floor slab uplift due to in-plane rocking of the webs on the top boundary conditions and the out-of-plane stability of the flange.

Realistic modelling of contributions by floor slabs in the earthquake safety assessment of buildings

ABSTRACT The conventional structural design of buildings often neglects the significant contributions of the coupling action of the floor slabs, potentially leading to unsafe designs against seismic actions. The interaction between reinforced concrete (RC) frames and shear walls, especially through slabs, plays a crucial role in the structure’s behaviour under seismic loading. In Australian construction, where wall-type systems are prevalent, it is essential to understand the complex interactions between coupled walls and columns facilitated by slabs. This study addresses this issue by proposing an innovative strain-based model, validated through finite element analysis. The proposed model, when compared with existing simplified models, demonstrates superior accuracy and effectiveness. This innovative approach not only enhances our understanding of seismic behaviour but also offers a straightforward solution that can be easily implemented in practice. Key findings reveal that slab interaction increases material strain and inelastic force capacity while reducing displacement capacity, particularly affecting smaller elements like gravity load-carrying columns. This improved understanding can lead to more effective strategies for enhancing the seismic resilience of RC buildings.

Experimental and numerical studies on seismic performance of a novel lead viscoelastic coupling beam

Replaceable coupling beams (RCBs) with different types of dampers have gained significant attention in coupled shear walls for enhancing seismic performances in high-rise buildings, showing superior advantages to conventional reinforced concrete coupling beams (RCCBs). Recently, the authors proposed the hybrid lead viscoelastic damper (HLVD), and its basic mechanical behaviors were experimentally studied. This paper used the HLVD as a replaceable fuse and installed it in the coupling beam to form a new RCB, i.e., lead viscoelastic coupling beam (LVCB). To examine the seismic performance of the LVCB, experimental and numerical studies were carried out in the present study. Quasi-static tests were conducted to comparatively investigate the seismic performances of the RCCB and LVCB. The experimental findings revealed that the RCCB experienced shear failure with severe pinching behaviors under cyclic loadings, while the LVCB exhibited a resilient behavior, showing favorable energy dissipation capacity with a ductile deformation capacity exceeding a rotation angle of 0.04 rad. The LVCB also demonstrated excellent recoverability in repeatability tests, proving its merit for maintaining post-earthquake functionality. Numerical simulations indicated that adjusting the lead rods of the LVCB could conveniently enhance the load-carrying capacity and energy dissipation capacity of the LVCB. The isolated floor slab was recommended as a low-damage control solution for the LVCB to facilitate post-earthquake replacement.

Metode Pelaksanaan Pekerjaan Struktur Balok dan Pelat Lantai 2 Pembangunan Gelanggang Generasi Muda Majalengka

Beams and Floor Plates are a very important construction structure in a building. In carrying out work on floor slabs and beams, a method is needed to complete the work in the field. Especially when facing obstacles caused by field conditions that do not match previous expectations. For this reason, applying construction implementation methods that are appropriate to field conditions will be very helpful in the process of completing construction projects. Research on the construction method for the beam and floor slab construction was carried out at the Majalengka Young Generation Center construction. The casting method for the beams and floor slabs is conventional using ready mix concrete with a slump test value of 12 ± 2. From the results of the research on the construction implementation method for the Majalengka Young Generation Arena, it was found that: beam and floor plate work includes, preparatory work includes measuring work, scaffolding installation and formwork installation, then there is reinforcement/reinforcing work, namely steel fabrication in the project area, then there is work Casting the beams and floor plates using a tower crane. Next, maintenance work is carried out on the concrete mixture during the drying process, namely by watering according to regulations.

How to combine different types of prefabricated components in a building to reduce construction costs and carbon emissions?

In the context of industrialized construction and carbon emission reduction globally, prefabrication has gained considerable attention. However, most studies cared the carbon emissions and construction costs from the perspective of a whole prefabricated building rather than the prefabricated components. It makes it difficult to understand the role of prefabricated components play and make improvements from the prefabricated components level. To fill this gap, this study proposes a model to optimize the selection and combination of prefabricated components in a building project to simultaneously reduce the construction costs and carbon emissions. Six common component types were considered: shear wall, beam, floor slab, stair, balcony, and air-conditioning slab. Their costs and carbon emissions were quantified when adopting prefabrication and cast-in-situ technologies. To obtain the optimal solution, we developed an improved multi-objective mayfly algorithm (IMOMA), which incorporates enhanced circle chaos mapping and a global best guiding strategy to generate Pareto solution sets. The performance of IMOMA was evaluated using the Zitzler-Deb-Thiele series test functions, demonstrating its advantages in convergence, diversity, and comprehensive performance through metrics such as generation distance, diversity metric Δ, and inverse generational distance. A case study validated the effectiveness of this proposed method, demonstrating an average reduction of 9.05% in total construction costs and 8.04% in carbon emissions when compared to the initial scheme. Further study revealed that different prefabrication rates correspond to different optimal components combination schemes, with different trends in the costs and carbon emission curves as the prefabrication rate increases. Additionally, carbon trading policies influence the components combination, with construction costs reduced by 10.88% at a carbon trading price of 42.80 CNY/t CO2eq. This study provides valuable guidance for general contractors to design optimal component combinations and for governments to promote the sustainable development of prefabricated construction.

THE INFLUENCE OF CHLORIDE IONS CONTENT ON THE MECHANICAL PROPERTIES OF CONCRETE

This paper presents an analysis of the effect of concrete salinity on the splitting tensile strength of specimens taken directly from the HC-500 floor slab and the flexural and compressive strength and the value of the modulus of elasticity of specimens made under laboratory conditions from lightweight concrete and ordinary concrete. The tests were carried out in two variants: in the first, chloride ions were introduced into the concrete by the migration method and in the second, as an additive introduced directly with the batch water. The analysis showed that the additive can affect certain mechanical properties of concrete both favorably and unfavorably. The results indicate that it is important to examine the issue of the influence of salinity on concrete’s mechanical properties. This knowledge can be applied to the modeling of damage in reinforced concrete structures resulting from exposure to chloride-rich environments.

RESULTS OF THE TECHNICAL INSPECTION OF A MULTI-STORY RESIDENTIAL BUILDING DAMAGED AS A RESULT OF A ROCKET IMPACT

The article presents the results of the examination of the technical condition of part of the construction structures of the building damaged as a result of a missile strike, the determination of the characteristics and classification of their defects and damage, the provision of conclusions and recommendations regarding the correction of the life cycle and further safe and reliable operation of the building. As part of the study, the object of the survey was a monolithic 22-story residential building with a basement (ATP) floor and a complex configuration in plan. The structural scheme of the complex is a monolithic reinforced concrete frame with stiffening cores. The stability and rigidity of the frame is ensured by diaphragms of stiffness in the form of reinforced concrete walls, elevator-stair nodes and rigid nodes connecting pylons and horizontal disks of monolithic reinforced concrete floor slabs. During the examination, visual and instrumental methods of research were performed. Before the field work, measures were taken to collect design and archival information about the research object. Instrumental studies to determine the actual concrete strength of reinforced concrete frame elements and to determine the diameter, protective layer and pitch of the working rods of the reinforcing frames of the load-bearing elements were carried out by non-destructive methods. The calculation model of the spatial scheme of the structure of the frame of the residential building, taking into account the damage, was made in the subsystem (PS) "COMPOSITION" of the software complex (PC) "MONOMAH CAD". The result of the survey is conclusions and recommendations, which indicate the specifics of damage and types of defects, destruction and debris in various structural elements that were discovered during the survey. The general technical condition of the residential building is classified as emergency. As for the recommendations, two options for carrying out repair and restoration works were provided. The first option is to restore the plan-elevation position of the building, the design marks of vertical and horizontal structures and the unloading of overloaded structures, to be performed with the help of an automatic hydraulic complex. The second option is the arrangement of temporary strengthening of emergency structures with the help of a metal space frame, without restoring the planned height position of the residential building.

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.

Research on Train-Induced Vibration of High-Speed Railway Station with Different Structural Forms.

Elevated stations are integral components of urban rail transit systems, significantly impacting passengers' travel experience and the operational efficiency of the transportation system. However, current elevated station designs often do not sufficiently consider the structural dynamic response under various operating conditions. This oversight can limit the operational efficiency of the stations and pose potential safety hazards. Addressing this issue, this study establishes a vehicle-bridge-station spatial coupling vibration simulation model utilizing the self-developed software GSAP V1.0, focusing on integrated station-bridge and combined station-bridge elevated station designs. The simulation results are meticulously compared with field data to ensure the fidelity of the model. Analyzing the dynamic response of the station in relation to train parameters reveals significant insights. Notably, under similar travel conditions, integrated stations exhibit lower vertical acceleration in the rail-bearing layer compared to combined stations, while the vertical acceleration patterns at the platform and hall layers demonstrate contrasting behaviors. At lower speeds, the vertical acceleration at the station concourse level is comparable for both station types, yet integrated stations exhibit notably higher platform-level acceleration. Conversely, under high-speed conditions, integrated stations show increased vertical acceleration at the platform and hall levels compared to combined stations, particularly under unloaded double-line working conditions, indicating a superior dynamic performance of combined stations in complex operational scenarios. However, challenges such as increased station height due to bridge box girder maintenance, track layer waterproofing, and track girder support maintenance exist for combined stations, warranting comprehensive evaluation for station selection. Further analysis of integrated station-bridge structures reveals that adjustments in the floor slab thickness at the rail-bearing and platform levels significantly reduce dynamic responses, whereas increasing the rail beam height notably diminishes displacement responses. Conversely, alterations in the waiting hall floor slab thickness and frame column cross-sections exhibit a minimal impact on the station dynamics. Overall, optimizing structural dimensions can effectively mitigate dynamic responses, offering valuable insights for station design and operation.

Design of a Six-Story Teaching Building: A Comprehensive Approach to Safety and Structural Efficiency

This paper describes teaching building design. The project, designed for the teaching building, prioritizes safety in its main structure, a reinforced concrete frame with six floors above ground. The story heights are 4.2m, 3.9m, 3.9m, 3.9m, 3.9m and 3.9m, respectively, and the building's total height is 27.6m. The construction site category is classified as type II, and the first group's seismic fortification intensity is 7 degrees. The process includes architectural design, structural design, and PKPM checking calculation. Architectural design mainly consists of a general description. The plan, elevation, section, and draft of the corresponding building are drawn according to the relevant information and requirements provided by the design task book. Structural design mainly includes load statistics, calculation of internal force and displacement of the frame, a combination of internal force, and calculation of staircase, slab roof, floor slab and frame structure. The calculation of displacement, internal force, and reinforcement of the whole frame structure is carried. Out using PKPM. In the course of architectural design, safety is a paramount consideration, in line with the principles of safety, applicability, beauty, economy, and energy-saving requirements, referring to national standards and relevant materials, and strictly following the requirements of relevant architectural design standards, the design of each link is not only a comprehensive scientific consideration of its own but also a related discussion with teachers, as detailed in the construction plan. The frame structure is adopted,in this structural type. It mainly includes structure layout and calculation sketch determination, load calculation, internal force calculation, internal force combination, main beam section design, and reinforcement calculation, frame column section design and reinforcement calculation, secondary beam section design and reinforcement calculation, floor and roof design, staircase design etc. Among them, the D-value method is used to calculate the internal force of the structure under horizontal load, and the distribution method is used to calculate the internal force of the structure under vertical load (dead load and live load).

Water proofing performance assessment of hydrophobic agent-based Portland cement concrete: A multi-dimensional experiment approach

Heavy rainfall led to excessive water infiltration and saturation in the concrete surfaces, resulting the dampness. This can adversely affect the aesthetical view, durability and strength of the concrete over time. However, hydrophobic cement is a specialized type of cement that has been developed to exhibit resistance to water penetration in the cement composite, which enhance the durability of concrete structure. In this research, hydrophobic Portland cement concrete (HPCC) specimens were assessed considering the mechanical strength properties, water absorption by different methods, and microscopic observations of hydration products. It was revealed that the compressive strength (CS) of HPCC concrete achieved around 28.7 MPa and 35.6 MPa at 7d and 28d, respectively having water to cement (W/C) proportion 0.45. The splitting tensile strength of HPCC samples having W/C 0.45 also found around 1.98 MPa and 2.43 MPa at 7d and 28d, respectively which values were higher as compared to control OPC specimens. In addition, HPCC concrete specimens showed capillary water absorption at 90d for 1D, 4D and 6D about 0.25 %, 0.36 %, and 0.39 %, respectively which was lower than that of PCC concrete samples. Moreover, the HPCC concrete plate specimens shown significantly lower water penetration by static vertical water pressure, for example concrete plate having 100 mm thickness presented around 2.6 mm water absorption depth at 90days. Furthermore, very few micro-pores were observed by SEM (scanning electron microscopy) in the microstructures of HPCC, whereas micro-cracks were not visible in the focus area. However, the findings might be applied in the construction sectors to protect the exterior building walls, roof floor slabs and plastering the concrete surfaces from dampness.

Identifying the evolution of through cracks in iron-reinforced hollow slabs under the influence of a standard fire temperature mode

The object of this study is the fire resistance of reinforced concrete hollow slabs at the onset of the limit state of loss of integrity. The problem of accurate modeling of the formation and development of cracks in concrete was investigated. The paper reports an analysis of the results of the stress-strain state of a reinforced concrete hollow slab during fire exposure for devising a method for evaluating the fire resistance of such structures upon the onset of the limit state of loss of integrity. According to EN 1992-1-2, the determination of fire resistance of structures is provided by calculation methods, however, there is no such procedure for reinforced concrete hollow slabs. Many scientific works offer refined methods for evaluating only the loss of load-bearing and heat-insulating capabilities, leaving aside the issue of loss of integrity. Thus, this can lead to a biased evaluation of reinforced concrete hollow floor slabs according to the criterion of the limit state of loss of integrity, which in turn can put under a threat to the fire safety of buildings, which threatens the life and health of people. According to the results of the calculation, a parameter has been determined, according to which the onset of the limit state of fire resistance, in particular, the loss of integrity, was established. Summarizing the damage distributions, it was assumed that in the case of reaching the critical plastic deformation of 2.5e-3 in concrete finite elements, they are excluded from the general set of finite elements. Thus, in the case of the formation of through cracks, the removal of finite elements is taken as a parameter to identify the onset of the limit state of loss of integrity. According to the results of the computational experiment, it was established that through cracks in a fragment of a reinforced concrete hollow slab are formed in 44 min. According to the results of the research, the method of evaluating the fire resistance of such structures based on the onset of the limit state of loss of integrity has been substantiated. Such a method could be applied during design, which provides an opportunity to determine the limit of fire resistance in reinforced concrete hollow slabs

Research on New Method for Safety Testing of Steel Structures—Combining 3D Laser Scanning Technology with FEA

This paper introduces a novel approach to assessing structural safety, specifically aimed at evaluating the safety of existing structures. Firstly, a point cloud model of the existing commercial complex was captured utilizing three-dimensional (3D) laser scanning technology. Subsequently, an intelligent method for identifying holes within the point cloud model was proposed, built upon a YOLO v5-based framework, to ascertain the dimensions and locations of holes within the commercial complex. Secondly, Poisson surface reconstruction, coupled with partially self-developed algorithms, was employed to reconstruct the surface of the structure, facilitating the three-dimensional geometric reconstruction of the commercial complex. Lastly, a finite element model of the framed structure with holes was established using the reconstructed 3D model, and a safety analysis was conducted. The research findings reveal that the YOLO v5-based intelligent hole identification method significantly enhances the level of intelligence in point cloud data processing, reducing manual intervention time and boosting operational efficiency. Furthermore, through Poisson surface reconstruction and the self-developed algorithms, we have successfully achieved automated surface reconstruction, where the resulting geometric model accurately reflects the dimensional information of the commercial complex. Additionally, the maximum uniformly distributed surface load that the floor slabs within the framed structure with holes can withstand should not exceed 17.7 kN/m2, and its vertical deformation resistance stiffness is approximately 71.6% of that of a frame without holes.

Collapse behavior of fully prefabricated composite frames with segmented PC floor slabs in a middle column removal scenario

Fully prefabricated steel-concrete composite (PSCC) structures come into being when precast concrete (PC) floor slabs are used to replace cast-in-situ concrete slabs, which possess the advantages of time-saving and convenient construction without or with less cast-in-situ concrete. However, segmented PC slabs decrease the integrity of composite frames and enhance the collapse risk under extreme incidents. To investigate the collapse behavior of fully PSCC frames, a reduced-scale PSCC frame substructure with segmented PC slabs was designed and tested under the monotonic load in a middle-column-removal scenario. The test results show that PC slabs near the middle column were severely crushed during the collapse; and the fracture of the girder was observed at the large deformation stage, originating from a bolt hole in the upper girder flange nearest to one side column and the weld connecting the girder with the other side column. The steel girder sections adjacent to the gaps between adjacent PC slabs presented superior continuity in stress when the segmented PC slabs were connected with steel splice plates (SSP). Meanwhile, both flexural and catenary actions in the composite beams provide the collapse resistance, and the contribution of the catenary action in the beams to the collapse resistance should be prudently considered due to the local buckling of the steel girders. Parametric analysis referring to the test was performed in the finite element (FE) method. Numerical results indicate that connecting the adjacent PC slabs with SSPs could alleviate or eliminate the fluctuation of the bending moments in the girder sections around the gaps. PSCC frames with segmented PC slabs usually present two typical collapse failure modes, the primary difference of which lies in whether limited plastic regions appear in the steel girder sections near the gaps. A simplified theoretical method was presented to decouple the contribution of the collapse-resisting mechanisms to the collapse resistance, and the analysis showed that catenary action provided 81.0 % ∼ 93.4 % of the total collapse resistance at the ultimate collapse stage.

Modeling a poiseuille flow through a rectangular pipe in a floor slab (PSD)

This study was devoted to the modeling of a laminar fluid flow in a pipe of the rectangular section located in a floor slab. This theme was raised because of its relevance in the large business sector as well as in the areas of energy saving and storage at the residential scale. The equations of motion quantity and heat transport are the classical equations of forced convection. However, to describe the movement amount within the heating slab pipeline, Prandtl simplified model was most appropriate. In addition, this model retains the most important terms for a laminar regime flow. In addition, the modeling of fluid flow conservation in the pipeline was taken into account in the equation system. To achieve the above-mentioned objective, a numerical resolution was made for the system resolution of the Navier-Stokes equations that govern this fluid flow. These equations were discretized by an implicit finite difference method. The system of algebraic equations as well as obtained was solved by the algorithm of Gauss and the algorithm of Thomas. The results obtained such as: the evolution of the fluid velocity profile within the slab according to pipeline to the Reynolds number variation, the fluid temperature have clearly demonstrated the Poiseuille effect on fluid flow. Moreover, the stabilization of the Gauss algorithm and the Thomas algorithm in this numerical modeling was well verified against the tricks that were taken into consideration. The result of this study was that Thomas algorithm and Gauss algorithm are the best in this type of numerical modeling.

Flexural performance of innovative thin-walled steel–timber composite floor slabs

A floor slab carries and distributes the floor load in a structure and is an important component that affects overall structural performance. Therefore, it is important to investigate the mechanical properties of such materials. In this study, flexural performance tests under static load are conducted for an innovative thin-walled steel–timber composite floor slab, and the failure mode, bearing capacity, stiffness, deflection, and strain development are investigated. The results show that the floor slab can be quickly assembled using self-tapping and wood screws and exhibits good flexural performance. Using ABAQUS finite-element software, the effects of the oriented-strand board (OSB) thickness, thin-walled–steel-plate height, steel strength, and boundary conditions on the flexural performance of composite floor slabs are investigated. Furthermore, based on the EN1995–1-1 code and equal-section conversion principle, the simplified beam-unit model is established for the theoretical calculation of the composite floor slab. The effective bending stiffness is calculated by considering the influence of the slip modulus of the connector, and the stress distribution law of the section is analysed. The results provide a reliable design basis and reference for the application of thin-walled steel–timber composite floor slabs in engineering practice.