Concrete Floor Slabs Research Articles

Analiza životnog ciklusa aramiranobetonske ploče kroz tri scenarija gospodarenja otpadom

This paper presents a life cycle analysis (LCA) of a reinforced concrete floor slab with special emphasis on the end of life (EoL). Three EoL waste management scenarios were presented: Scenario I (current situation of construction and demolition waste management in the Republic of Croatia), Scenario II (100% landfilling of construction and demolition waste), and Scenario III (complete recycling of construction and demolition waste). The aim of this study is to demonstrate the environmental benefits of recycling in terms of sustainable construction and to determine the phases in the life of reinforced concrete floor slabs that have the greatest negative impact on the environment. From the analysis, the largest negative contribution to the environmental impacts is in the production phase, which includes the supply of raw materials, their processing, and the transportation of products to the concrete and reinforcement plants. EoL analysis showed that the manner in which construction and demolition waste is managed has a significant impact on the values of the impact categories of human toxicity (HTP), freshwater and marine aquatic ecotoxicity (FAETP and MAETP), terrestrial ecotoxicity (TETP), and eutrophication (EP). Conducting an LCA focusing on the EoL is critical, as it can provide valuable insights into the environmental impacts of the disposal phase and help develop strategies for sustainable waste management.

Finding Patterns of Construction Systems in Low-Income Housing for Thermal and Energy Performance Evaluation through Cluster Analysis

Energy consumption in buildings depends on many factors, including envelope materials. This paper aims to propose a method based on cluster analysis for finding reference models based on actual construction systems of low-income housing. Such reference models can be used in future thermal and energy performance studies. Data on the envelope composition of a sample of 106 dwellings were obtained through a field survey in Florianópolis, southern Brazil. Cluster analyses were performed to group similar materials and construction systems together, and therefore, a reference model was obtained for each cluster. Computer simulations and hypothesis tests were performed to verify whether the reference models represented the sample. Three reference models were obtained from the cluster analysis. Cluster 1 comprised houses with ceramic-brick walls, concrete floor, and concrete slabs. Cluster 2 comprised houses with ceramic-brick walls, concrete floor, ceramic tiles, and wooden ceilings. Cluster 3 comprised houses with wooden walls, wooden floor, cement tiles, and wooden ceilings. Cluster 1 performed better than the other clusters in the cold season (mean degree-hour was 1299 for cooling and 1361 for heating in the reference model). Cluster 2 performed better the other clusters over the hot season (mean degree-hour was 1014 for cooling and 1451 for heating). Cluster 3 showed the worst performance (mean degree-hour was 3793 for cooling and 2988 for heating). Thus, the hypothesis tests have shown that the three reference models differ from each other and can represent their clusters properly. Cluster analysis was a practical and objective method for obtaining reference models.

Stress and shear of steel reinforced floors with prefabricated units and steel beams

Steel-reinforced concrete floors with prefabricated reinforced concrete slabs are industrial quickly erectable structures. The use of such structures makes it possible to reduce construction time, save metal, obtain efficient structures without beam projecting up to 20 m for loads produced by buildings and car parks. Codes and foreign norms do not include prefabricated reinforced concrete floor slabs in the operation of combined structures, as designers try to avoid complex connections (welding, bolts) during construction. Of obvious interest is the inclusion of precast slabs in the operation of combined steel and reinforced concrete beam as well as grouted joints between steel and slabs in the absence of additional anchors and connections.Experimental results of structural models and 6×10 m floors with precast slabs are considered to identify the concrete shear. The effective shear deformation up to 0.5 mm is detected even without additional anchors. Simplest anchors significantly increase the joint operation of cast concrete and steel profile. The operation mechanism is determined for steel-concrete and steelconcrete-anchor contact zones, and respective diagrams are plotted for numerical calculations.Floor testing shows that the use of the simplest joining, cast reinforced concrete combining steel and precast elements involves precast slabs at a distance from the beam axis of at least two thicknesses of the floor for two different ways of the beam support.Numerical modelling, including the contact zone operation, shows good agreement with the experimental data. It is recommended to clarify the width of compressed concrete flange in normative documents for the structural analysis.

Large-scale shaking table tests of a six-story floor-by-floor assembled CFS frame-framing shear wall structure

To study the seismic performance of a proposed multi-story floor-by-floor assembled structure using cold-formed steel (CFS) frame with square columns and double-channel beams connected by novel joints, and CFS framing walls as shear walls, shake table tests were conducted on a 2:3 scaled six-story CFS frame-framing shear wall structure (CFSF-FSWS) using bidirectional seismic inputs. A prefabricated concrete floor slab was proposed utilizing the channel section beams as the molds during prefabricating processes. The CFS framing shear walls were designed with various configurations researched before: framed or trussed skeleton, single or double side sheathing, flat or corrugated steel sheathing sheet. The observed damages, dynamic properties, seismic responses and failure mechanisms of the CFSF-FSWS under different peak ground accelerations (PGAs) were analyzed. The CFS frame carried gravity load, and the horizontal earthquakes were mainly resisted by CFS framing shear walls. The results indicated a good deformation capacity and seismic performance of the CFSF-FSWS building. The damping ratio of the test model gradually increased with the accumulation of damage, varying between 3.30%∼6.95%. After all seismic loading, the CFS frame remained intact and the damages were concentrated on the CFS framing shear walls, achieving the design objective of “separated gravity and lateral resisting systems”.

Impact of falling debris on reinforced concrete slab

The work is devoted to the analysis of one of the possible limit states, for which the scenario is the collapse of the floor over a remote column, as a result of which a general collapse of the rancake-type collapse occurs. An approximate method of assessing the progressive collapse of a reinforced concrete floor slab of a multi-story building, which will receive an impact from falling fragments of failed structures, is proposed. The technique's underpinning is the dynamic analysis of a simplified module of motion, the form of which is assumed to be similar to that used in the theory of limit equilibrium. It is assumed that the elastic work of the plate has little effect on the final value of the deformation that occurs in the casting in the form of linear plastic hinges. Part of the kinetic energy of the falling debris is transferred to the plate that receives the impact, it is theoretically as in the classical case the completeness of the plastic impact. The resulting differential equation of motion is integrated in a closed form. The use of the proposed technique is demonstrated with the help of an illustrative example.

Experimental Study on Flexural Behavior of the Composite Bottom Slab of the Stiffened Steel Truss

In order to study the influence of rib size on the flexural performance of the new reinforced truss concrete composite floor slab, two precast reinforced concrete floor slabs and one ordinary reinforced truss composite floor slab were designed and manufactured for flexural performance tests. The failure mode of the concrete slab under uniform load was analyzed, and the influence of rib size on the flexural capacity of the floor slab was studied. The results show that the stiffening of the steel truss composite slab can significantly improve the stiffness of the precast slab and effectively solve the problem of excessive deflection of the precast slab during construction. On the basis of the experimental study, the influence of the top chord steel bar diameter, concrete rib height and rib width on the short-term stiffness of the floor is deeply analyzed by using the finite element refined modeling. The results show that the diameter of the top chord reinforcement and the width of the concrete rib are positively related to the stiffness of the composite slab, and the height of the concrete rib has little effect on the initial stiffness of the precast slab, which mainly plays a role in the later stage.

Critical collapse deformation of 3-D steel frame with composite floor system

Determination of the CCD (critical collapse deformation) for frame structures is crucial to calculate their final collapse resistance due to a column loss. This paper studies the CCD of 3-D (three-dimensional) steel frame structure in an interior column loss. The work presented in this paper is an extension of previous work by authors on two-dimensional (2-D) steel frame, by further introducing the effects of concrete floor slab. The fracture of steel is considered by Bai-Wierzbicki model, in which the effects of Lode angle and stress triaxiality on fracture of steel are accounted for. The Bai-Wierzbicki model is imported into software ABAQUS by a user-defined subroutine. The CCDs of 2-D steel frame, 3-D steel bare frame, and 3-D steel frame with floor slab due to an interior column loss are compared. The effects of beam span, beam height, slab thickness, and slab aspect ratio on the CCD of 3-D steel frame are studied. For steel frame with different slab span-to-thickness ratios, explicit calculation formulae are established to calculate the CCD of steel frame. It is found that due to the existence of floor slab, the CCD of steel frame is significantly reduced. A larger span-to-depth ratio for steel beam ensures a greater CCD of steel frame. For a certain slab span-to-thickness ratio, the CCD-to-depth ratio of steel beam is almost linear against the span-to-depth ratio of steel beam. Moreover, the CCD of steel frame increases when the slab aspect ratio increases.

Finite Element Analysis of the Bearing Capacity of Beamless Floor Slabs under Punching, Taking into Account the Design Parameters of the Contacting Elements

Static calculations of experimental models in an elastic formulation were carried out, and the regularities connecting the dependences of forces in the calculated cross-section of punching out from the main structural parameters of contacting elements (reinforced concrete slabs and pylons) and from the used concrete class were revealed. This article concerns the safety issues of reinforced concrete slabs under punching with different ratios and combinations of pylon and slab thickness parameters, as well as concrete strength. The objectives of the research are consideration of the fracture pattern of reinforced concrete monolithic slabs due to punching shear; comparative analysis of modern normative calculation methods and flat reinforced concrete slabs due to static punching shear; finite element modelling and analysis of the punching shear calculation results for reinforced concrete floor slabs; and the force distribution over the area of the contacting elements-saw and floor slab. The practical significance of the results lies in the use of the obtained forces in the contacting elements for the calculation and design of reliable structures of beamless floor slabs.

Material and Environmental Aspects of Concrete Flooring in Cold Climate

Dehydration of concrete floor slabs is a critical step to ensure that the flooring material adheres properly and that there is no moisture-related damage to the floor after installation. Dehydration in a cold climate is often a slow process, which can have a big impact on the overall duration of the construction project, and corresponding measures are often taken to accelerate the drying process, especially in constructions exposed to a cold climate. One common method, typically used to accelerate dehydration in cold weather, is to introduce internal heating cables into the slab. This method reduces the dehydration time, but may not be the best solution from a sustainability perspective. This paper presents a concept study of concrete flooring in a cold climate from a cradle to practical completion perspective. The study focused on the environmental and material aspects of the dehydration of concrete floors in a cast-in-place house. This paper showed that concretes with high water-cement ratios, which are typically preferred due to their low CO2 emissions, may require measures for accelerated dehydration, which ultimately results in a higher environmental impact. The importance of environmental studies is also highlighted to fully understand the environmental aspects of construction.

Evaluation of the dynamic response for scaled models of shaped concrete floor slabs

The dynamic response of building structures is an essential design consideration in building acoustics. However, building design is increasingly driven by sustainability goals. Floors can be optimized to reduce material consumption and corresponding carbon emissions, yet geometric changes may cause sound insulation and vibration problems. Although the dynamic performance of traditional floors is well established, the performance of non-traditional shapes is less understood. Before trusting the results of building simulations encompassing optimized floors, the dynamic results should first be validated experimentally. This paper details a numerical finite element analysis method to ascertain the dynamic response of four shaped concrete slabs, with experimental modal analysis used to validate the numerical results. The material properties in the numerical model are updated to match the experimental results. The findings support a computational framework for determining the dynamic response of shaped structures that can then be implemented in future large-scale building models.

Experimental study on Glass Fibre Reinforced Gypsum-Reinforced concrete floor slab systems

Glass Fibre Reinforced Gypsum (GFRG) panels, with the cavities filled with reinforced concrete (RC), are being used as load-bearing walls in Australia, India and other Asian countries. The same GFRG panels can be placed horizontally for use as floor and roof slabs, with every third cavity filled with RC and provided with a screed concrete topping. Such GFRG-RC composite slabs are being increasingly used in India, with the structural design done conservatively (as RC ribbed one-way slabs), ignoring the contribution of GFRG and possible two-way action. This paper reports experimental and theoretical studies carried out on GFRG-RC slab specimens, 3 m × 3 m in plan and 174 mm thick, to explore the contribution of GFRG to flexural strength and stiffness. It is established that the contribution is quite significant, and this can be taken advantage of in the structural design. Further, it is shown that provision of joints in the GFRG does not adversely affect the performance of the composite slab.

PERBANDINGAN ANALISIS STRUKTUR PELAT LANTAI BETON KONVENSIONAL DAN PELAT LANTAI HASILPERHITUNGAN SOFTWARE SAP 2000 (MENARA USM)

The floor slab is designed to behave as a diaphragm during an earthquake (Ultimate limit states). Floor slabs are designed in such a way that deflection and vibration are within serviceability limit states. The criteria for the maximum plate deflection are used according to SNI 2847-2019.
 The analysis carried out is to compare the work of conventional concrete floor slabs and floor slabs as a result of the output analysis from the SAP 2000 software. The goal to be achieved in this study is to analyze the structure of conventional concrete slabs with the results of computer software to obtain the difference in plate reinforcement spacing so that it will be obtained optimal distance. From the conclusions of the research that has been carried out, it is obtained that conventional concrete floor slabs are narrower than the results of the spacing of the reinforcement from the software results, for the SAP output the spacing is more tenuous. Based on these results, for the selection of reinforcement spacing, it is recommended to use the smallest spacing. obtained by Manual analysis is at moment 11 of Mu = 11.109 kNm with a diameter used for Ø 10-100 mm reinforcement, while analysis with SAP 2000 software is obtained at moment 11 for M11 = 9.876 kN.m with a diameter used for plain reinforcement Ø10-150 .Based on the plate moment obtained by Manual analysis is at moment 22 of Mu = 7.454 kNm with a diameter used for reinforcement Ø 10-150 mm, while analysis with SAP 2000 software is obtained at moment 22 of Mu = 6.507 kN.m with a diameter used plain reinforcement Ø10-200.

ИДЕНТИФИКАЦИЯ ПАРАМЕТРОВ КУСОЧНО-ЛИНЕЙНОЙ ФУНКЦИИ РИСКА МЕТОДОМ АНТИРОБАСТНОГО ОЦЕНИВАНИЯ

The article reviews literature on identification methods for parameters of regression models, including those based on Chebyshev metrics. The publications contain data on the development of an algorithm for the unambiguous definition of Chebyshev projection; a new method that combines Minkowskian distance and Chebyshev distance, with both being used as a similarity measure in the clustering process when grouping data; generalizations of particular goal setting for curves and surface fitting to the data observed or calculated as a result of replacing least squares with the Chebyshev norm; and integral estimates of the anthropogenic transformation of the territory using multidimensional statistical methods. Using the anti-robust method of estimation, the authors have developed a method to estimate unknown parameters of a regression piecewise linear risk function, whose aim is to solve a linear Boolean programming problem. The risk function of the dynamics of the price per square meter of living space of dwellings in the housing market in the Russian Federation is built using the least modules method and the anti-robust estimation method. Average pricing for silicate wall blocks, concrete floor slabs, and ready-mixed concrete are used as independent factors in the model. Both versions of the models built describe the dynamics of the output indicator profoundly, as evidenced by the high values of adequacy criteria, and therefore can efficiently solve the forecasting problems. It has been established that the number of maximum module errors of the risk model approximation is equal to three, i. e. the number of independent variables, when applying the anti-robust method.

Tests of reinforced concrete floor slab with initial crack

This study presents the results of the examination of precast reinforced concrete floor slab with initial crack of continuous rectangular cross-section with nominal dimensions 6380*3230 mm and a height of 160 mm. The slab was manufactured in the factory during summer. Concrete curing took place in natural conditions without the use of heat and humidity treatment. The slab has an initial crack that appeared before the test, located in the middle of the span in the direction of the channel-former in the layer of concrete with minimum thickness. Information on the testing procedure is presented, the results of calculations and full-scale tests are given. The analysis of the slab deformation dependence diagram on the load value is carried out. The conformity of crack resistance, stiffness and load-carrying capacity of a slab with an initial crack to the normative requirements has been checked, and the theoretical and experimental results have been compared. The influence of the initial crack in the slab on its stiffness and crack resistance has been established.

A Method of Evaluating the Destruction of a Reinforced Concrete Hollow Core Slab for Ensuring Fire Resistance

Fire tests of reinforced concrete floor slabs do not allow the detection of the onset of the boundary state due to loss of entirety because blocks are installed on the unheated surface to reproduce the design load. This prevents the formation of cracks through which toxic combustion products, smoke, and temperature spread can penetrate. Determining a building structure’s actual fire resistance limit was fixed at the onset of any fire resistance boundary state. It was proven that calculation methods for fire resistance assessment have significant advantages over experimental methods. To reduce the number of finite elements for a rational calculation of the fire resistance assessment of a reinforced concrete hollow core slab, a geometric model of 1/4 of this structure was built. The possibility of visualizing the studied structure at full scale was realized when obtaining the calculation results. The stress-strain state of the studied structure was evaluated based on the thermal and mechanical loading results applied to the reinforced concrete hollow core slab. Thus, the work’s objective was achieved based on the calculation experiments’ results. A methodology was developed for calculating the destruction of a reinforced concrete hollow core slab while assessing its fire resistance. Scientific fundamentals for determining the onset of the boundary state of loss of entirety were developed. The proposed methodology allowed for a reliable assessment of the fire resistance of such structures.

TESTING OF HOLLOW-CORE END NOTCHED FLOOR SLAB

This paper examines the test results of a hollow-core reinforced concrete prestressed end-notched floor slab of formwork formation subjected to uniformly distributed load.
 The research of the end-notched slab was carrying out in the testing hall of the State Enterprise "State Research Institute of Building Structures" according to the procedure of standard DSTU B B.2.6-7.
 Vertical uniformly distributed load was applied to the end-notched slab with cross-rails and support fixtures for loading, with hydraulic jacks and pumping station equipped with force meter.
 The end-notched slab was subjected to step-by-step loading with load steps of 100 kgf/m2.
 Inspection of the surface of the end-notched slab in the test area, with recording in the register of measurement results of displacements and potential damages was carried out after every loading step.
 Vertical displacements of the end-notched slab corners were measured with four clock type indicators ICH-10. Vertical displacements of the middle slab span were measured with two deflectometers 6PAO. The middle span deflection of the end-notched slab was calculated considering corner displacements.
 Based on the results of research, it was established that before applying the load of 800 kg/m2 there were not detected cracks the opening width of which exceeded the limit values.
 The loss of loadbearing capacity of the end-notched slab was detected after the load of 1280 kgf/m2, which which exceeded the design load by 1.6 times. The end-notched slab collapsed due to loss of shear resistance.
 According to the test results, it was established that hollow-core reinforced concrete prestressed end-notched floor slab meets the requirements of strength, stiffness and crack resistance.

Finite element analysis of floor slabs by means of visual programming in SAPFIR-3D

To calculate analytical model of buildings and receive stress-strain state results, triangulation of structural elements is required. Great attention should be paid to reinforced concrete multi-span floor slabs at the joints with vertical elements. Due to unevenness and complexity in form, the finite element mesh of slab in such places can become more concentrated, which leads to an increase in stress values and inadequately elements design. To prevent such negative consequences and create an even mesh all over the slab, additional mesh generation in such places is required. To simplify such problem and reduce human costs, adjustment of finite element (FE) mesh can be obtained by means of visual programming. The purpose of this paper is to obtain and compare the results of finite element analysis (FEA) of reinforced concrete floor slab in residential building and to adjust generated mesh at the joints with vertical elements by means of visual programming in SAPFIR-3D. The scientific and practical importance of the work stands in the describing of the method of adjustment of FE mesh generation of floor slabs at the joints with vertical elements by means of visual programming. The results of the research are based on the results of calculation in programming complexes SAPFIR-3D and LIRA-SAPR, also analysis of literary sources and practical experience of the authors. The article revealed the possibility usage of visual programming to adjust FE mesh of floor slab with aim to simplify its shape at the joints with vertical structural elements. There is considered method and options for visual programming in the SAPFIR-3D. In this paper, results of the 8-storey skeleton reinforced concrete residential building with basement, have been analyzed and compared. The practical importance of the results of this paper lies in the presentation of the proposed method to adjust FE mesh of floor slab by means of visual programming.

PELAKSANAAN PEKERJAAN PLAT LANTAI DENGAN BETON PRECAST PADA PROYEK PENATAAN GGM TAHAP 1

Abstract
 The building structure is one of the most important elements in a building construction. So the selection of the right implementation method is very important to be able to get the best and maximum results. Replacing conventional methods to become more modern is one of the efforts that can be done by managers. As in the implementation of the skywalk work, it also uses a more modern method, namely by applying a precast concrete system to the floor slab.
 The purpose of this study: (1) to know and understand how to carry out the work of preparing/installing precast concrete floor slabs. (2) knowing and understanding how to carry out precast concrete connection work. From this it will be known the method of implementation, the stages of implementation carried out, the specifications of the precast concrete used, as well as the types and specifications of the heavy equipment used.The results of this study are: the implementation stage starting from the mobilization of materials, preparation work, HCS work and the last stage is the connection stage. The precast used are: Width 1,200 mm, Length 3,720 mm, Weight 932.14 kg. The iron used in the connection is D10 in size.
 Keywords: Precast concrete, Implementation Method, floor slab

ANALISIS PERBANDINGAN BIAYA DAN WAKTU PEKERJAAN PELAT BETON KONVENSIONAL DENGAN PANEL BETON

The New Classroom of Galuh University is a 2-storey building that uses concrete floor panel slab construction. The use of the concrete floor panel slabs is due to insufficient road access to the location to use ready mix cast concrete and to streamline project implementation time. The purpose of this study is to find out how much the cost and time comparison of the work of conventional concrete floor slabs and concrete floor panels is. This research was conducted in the new classroom building of Galuh University. The results of data analysis show that the budget required for conventional concrete floor slab work in Galuh University's New Classroom Building is Rp. 368,160,000.00,- with the price for 1 m3 is Rp. 4,613,524.65,-. And the budget needed for the floor panel slab work on the Galuh University New Classroom Building is Rp. 359,100,000.00,- with the price for 1 m3 is Rp. 4,500,000,000.00,-. Based on the price comparison, concrete floor slabs are about 2.46% more efficient than conventional concrete slabs. This is because there is a price difference of Rp. 9,060,000.00,-. The work time needed to complete the Conventional Floor Plate work is 27 days and the work time needed to complete the Floor Panel Plate work is 21 Days. Based on the comparison of work time, Floor panel plates are 22.22% more efficient for work time.

Experimental and theoretical analysis on truss construction robot: Automatic grasping and hoisting of concrete composite floor slab

AbstractThe development of various construction robots can significantly reduce the construction labor intensity and risk. We present an experimental task of a truss construction robot, including automatic grasping and hoist positioning of concrete composite floor slab. And, a control strategy matching the construction robot is proposed to solve the following problems: (a) Due to the widespread manufacturing errors of building components, the position deviation of diagonal web reinforcement on concrete composite floor slab may cause grasping failure. (b) The chaotic surface of the floor slab seriously affects the recognition accuracy of the grasping target. (c) The large mass and inertia of heavy‐duty hanger and concrete composite floor slab make it difficult for robot to achieve accurate positioning under eccentric load condition. The machine vision recognition system ensures that if the diagonal web reinforcement is detected more than half of the grasping path, the grapple hook can change the grasping path independently to prevent it from colliding with the offset diagonal web reinforcement. An anticollision and grasping path planning method based on machine vision is proposed to improve the success rate and efficiency of automatic grasping. The mean value of proportional speed and proportional position is introduced as the evaluation speed and evaluation position of driving wheel to improve the accuracy of multiwheel synchronization. Moreover, we analyzed the robot performance from actual grasping and hoist positioning process of the concrete composite floor slab. The experimental results show that the robot has a good performance on the automatic grasping and hoisting of the concrete composite floor slab.