Types Of Slabs Research Articles

EVALUATION OF STRUCTURE USING VARIETY OF SLAB TYPE UNDER PERFORMANCE-BASED DESIGN: CASE STUDY COMMON WORKING SPACE IN SURABAYA

Improvement of the current construction of midrise to high-rise building in Surabaya relatively needs to be evaluated, especially for compact office building area, it is very challenging to have an optimal space to the structural system with facilitate a satisfactory capacity performance. This paper makes a comparative study of the effectivity of structural plate structure in the compact office building between conventional slab (M1), waffle slab (M2) and flat slab (M3). A typical 5-story reinforced concrete building structure is selected as a case study within 6 m symmetrically span for each model. The proposed method used in this study is based on empirical analysis followed by numerical evaluation using SAP2000. The step initiated by deriving an optimal alternative of various type of slab. This study aims to emphasize the benefits to the functionality of the structural system which more efficient in term of structural capacity and its performance. As the result, M1 and M3 offer a similar behaviour due to the reinforcement and design performance with high slab deformation compared to the M2. M2 present a lower slab deflection under the supported of waffle element with the result almost twice smaller than M1 and M3.

Experimental Study on Flexural Behavior of RC–UHPC Slabs with EPS Lightweight Concrete Core

This paper presents an experimental investigation that focuses on the flexural behavior of an innovative reinforced concrete–ultra-high performance concrete slab with an expanded polystyrene lightweight concrete core. This type of slab is proposed to serve the semi-precast solution, in which the bottom layer is ultra-high performance concrete working as a formwork during the construction of semi-precast slab, the expanded polystyrene lightweight concrete layer is used for the reduction of structure self-weight, and the top layer is normal concrete designed to withstand compressive stress when the slab is loaded. Two similar large-scale specimens with dimensions of 6200 mm × 1000 mm × 210 mm were fabricated and tested under four-point bending conditions to investigate the flexural behavior of composite slab. Test results indicated that three different layers of materials can work effectively together without separation. The bottom ultra-high performance concrete layer leads to the high ductility of the slab and has a good effect in limiting the widening of the crack width by forming other cracks. According to design code ACI 544.4R, a modified distribution stress diagram on the composite section was proposed and proven to be suitable for the prediction of flexural strength of the composite section with an error of 3.4% compared to the experimental result. The effect of the ultra-high performance concrete layer on the flexural strength of the composite slab was clearly demonstrated, and for the case in this study, the ultra-high performance concrete layer improves the flexural strength of the slab by about 11.5%.

PERBANDINGAN FLAT SLAB DENGAN PELAT KONVENSIONAL TERHADAP PENGARUH BEBAN LATERAL

Construction development in Indonesia continues to experience massive growth, especially in technology and innovation. In high-rise buildings, many structural developments have various forms of structural design. A new type of slab used in Indonesia has emerged in recent years: the flat slab. A flat slab is a reinforced concrete construction supported directly by columns without beams. By not using beams, it has the advantage of reducing floor height, faster implementation time, and more economical implementation costs. This research will redesign the structure of a 9-storey hospital building in Kudus with a flat slab structural system and then compare it with a conventional slab structural system using the ETABS and Spcoloumn programs. The earthquake load used refers to the PUSKIM website. This study compares both structural systems' structural period, inter-story deviation, and fundamental earthquake force. From the comparison between the flat slab structural system and the conventional plate, it was obtained that the value of the vibrating period of the flat slab structural system was 11.82% greater in the X direction and 12.82% in the Y direction than the conventional plate structural system. The inter-story deviation of the flat slab is 26.86% greater for the X direction and 28.87% for the Y direction than the conventional slab structural system. The mass (weight) of the flat slab structural system is 8.37% greater than that of the conventional slab structural system. The primary earthquake force of the flat slab is 8.36% greater for the X direction and 8.4% for the Y direction than the conventional slab structural system. So, it can be concluded that a flat slab is less efficient in resisting lateral loads than conventional slabs.

Anion redox as a means to derive layered manganese oxychalcogenides with exotic intergrowth structures

Topochemistry enables step-by-step conversions of solid-state materials often leading to metastable structures that retain initial structural motifs. Recent advances in this field revealed many examples where relatively bulky anionic constituents were actively involved in redox reactions during (de)intercalation processes. Such reactions are often accompanied by anion-anion bond formation, which heralds possibilities to design novel structure types disparate from known precursors, in a controlled manner. Here we present the multistep conversion of layered oxychalcogenides Sr2MnO2Cu1.5Ch2 (Ch = S, Se) into Cu-deintercalated phases where antifluorite type [Cu1.5Ch2]2.5- slabs collapsed into two-dimensional arrays of chalcogen dimers. The collapse of the chalcogenide layers on deintercalation led to various stacking types of Sr2MnO2Ch2 slabs, which formed polychalcogenide structures unattainable by conventional high-temperature syntheses. Anion-redox topochemistry is demonstrated to be of interest not only for electrochemical applications but also as a means to design complex layered architectures.

Seismic Analysis of a Multi-Storey Building with Different Types of Slabs

Earthquake plays an influential role in the analysis and design of structures. Unless the structures are designed and constructed to withstand seismic forces, failure cannot be avoided. Buildings can be made seismically sound with proper structure design, detailing and construction practice. The configuration of a building is very much important for the seismic performance of buildings. The important aspects that affect the seismic configuration of a building are overall geometry and structural system. This parameter varies in their behaviour in the flat slab, waffle slab and conventional slab. Therefore introducing different types of slabs becomes very crucial for a structural engineer when it comes to better performance of RC structure. The objective of this paper is to study the seismic behaviour of multi-storeyed buildings with different types of slab systems. The study is done by considering the varying number of stories i.e. low-rise, mid-rise and high-rise buildings. The study aims to find an effective slab system for both regular and irregular structures. The different types of slabs considered are flat plate system, flat slab with drop system and waffle slab system which is compared with the conventional slab system. Seismic assessment using response spectrum analysis is done. For low-rise to high-rise buildings, the seismic behaviour of the waffle slab is more effective.

EVALUASI KAPASITAS STRUKTUR EKSISTING LANTAI JEMBATAN PADA JEMBATAN TYPE PILE SLAB DI RUAS JALAN TOL JORR W1 KEBON JERUK

This research a study transverse cracking that occurred on the floor structure of the pile slab type bridge located at JORR W1 Kebon Jeruk toll road. The purpose of this study was to evaluate the capacity of the bridge floor structure that had damaged by cracks and weather its remains are in a safe condition or not. The research method is carried out by analyzing the calculation of loading that occurred in an actual condition that had cracked by modeling on structural analysis program with standard SNI 1725:2016 and actual loads that acted on the structure, then evaluating the moment capacity of the structure based on installed reinforcement and evaluating deflection from inspection results based permissible deflection. From the results of the analysis, it was found that the structure experienced a moment failure due to the actual load with a load magnitude of 18,07 tons, the moment due to the actual load on the negative moment region was 34,47 tons.m and the positive moment region was 37,46 tons.m, compared to the moment capacity of structure successively which was 25,52 tons.m and 29,16 tons.m. However, for the results of the analysis of the standard load of 11,25 tons, the moment capacity of the structure was able to withstand the ultimate moment due to the reactor load successively being 22,82 tons.m and 24,37 tons.m, whereas for the deflection test results of 0,46 mm remained in a safe condition without exceeding the L/800 permit deflection of 4,76 mm. Based on the results of the analysis, it can be concluded that the structure is overloaded and in the future, the structural ability must be improved and it is necessary to strengthen the bridge floor structure to be able to increase the capacity of the structure so that it can withstand the working load.

Experimental and numerical investigation of punching behavior of two-way RC slab with different opening locations and sizes strengthened with CFRP strip

Flat slabs are widely used due to their advantages. However, punching collapse is a situation that should not be ignored during the design as a risk in this type of slab. The openings left around the column or opened later for various reasons negatively affect the punching strength of the slabs. Within the scope of the study, a total of nineteen flat slabs were produced to investigate this negative effect and to eliminate it with an appropriate strengthening method. In the study, the size and position of the two square-section openings adjacent to the column (around the column) were chosen as variables. In addition, identically produced slab test specimens with openings were strengthened with fan-type anchors and CFRP strips. Applied strengthening technique aimed to catch the punching strength of the reference test specimen without opening and, if possible, exceed this value by preventing the punching behavior that occurs in the slabs with openings, as mentioned in the first part of the study. It was determined that the anchored CFRP strips increased the load-carrying capacity of the opening test specimens by 50% on average. Energy dissipation capacity, initial stiffness, maximum bearing capacity, strain behavior of CFRP strips, failure modes, and crack distributions were interpreted using obtained experimental data. The specimens were modeled with the ABAQUS and numerically analyzed, and in the last step, the numerical results were interpreted by comparing them with experimental results.

Applicability Evaluation of Energy Slabs Installed in an Underground Parking Lot

A floor slab of buildings can be used as a ground heat exchanger by equipping heat exchange pipes with a horizontal layout, namely energy slabs. The thermal performance of conventional energy slabs is relatively low due to the interference with the ambient air temperature. This fatal drawback can be overcome by installing energy slabs in an underground parking lot, where the influence of ambient air is not significant. This study experimentally investigated the applicability of two types of energy slabs (floor type and wall type), which were constructed on the basement slab in an underground parking lot. In particular, an aerogel-type thermal insulation layer was fabricated in each energy slab to isolate it from the ambient air along with enhancing the structural stability against automobiles. In the thermal performance tests, the constructed energy slabs showed a thermal performance 265% higher than the conventional energy slabs. Moreover, the aerogel-type thermal insulation layer effectively prevented surface condensation. However, the thermal stress of 2350 kPa was induced by the cooling operation in the energy slabs, which means the energy slab should possess sufficient tensile strength to secure the structural integrity of the parking lot basement.

Elastic hangers for suspended ceilings - are they really needed?

Suspended ceilings made of several layers of gypsum boards are a common way to increase the sound insulation of slabs in buildings. The ceiling is typically hanging 100-500 mm below a slab. There are many manufacturers of the hangers and most of them supply elastic hangers, made of rubber or metal springs. The elastic hangers are very costly and there are very little scientific data of the effect of these elastic hangers, especially at low frequencies and especially for concrete slabs, which are the most common slab type. The sound insulation of normal buildings is increasing with frequency and the low frequency region is the most interesting region. The author has in more than 30 years been part of many cinema projects where elastic hangers has not been used. Still, the sound insulation at low frequencies is excellent. What are the most important parameters? Could it be that elastic hangers are even reducing sound insulation due to resonances at low frequencies? In this paper we will discuss measurement data both from laboratory and real buildings with focus on air-borne sound insulation at low frequencies. We will also discuss calculations methods.

Structural performance of hybrid fibres incorporated Re-Cycled aggregate RC slab

Concrete is a material that mainly consists of coarse aggregate and mortar. The forming of cracks is an existing problem in Reinforced Concrete (RC) slab. In this research, hybrid fibres namely steel and polypropylene fibres in suitable combinations are identified and incorporated to concrete to regulate the formation and development of cracks in RC slabs. In Hybrid Fibre Reinforced Concrete (HFRC), 1 per cent of steel fibre and 0.30 per cent of polypropylene fibre is added, which is the effective amount of reinforced concrete added based on information obtained from the various research studies. In addition, now-a-day use of re-Cycled Aggregate (RCA) is strongly recommended to address the lack of traditional coarse aggregate. By using RCA as a partial substitution of coarse aggregate with an inclusion of 1 % of steel fibre and 0.30 % of polypropylene fibre to the concrete volume in the study, a typical approach is recommended. One-way type of RC slab, 1350 mm × 500 mm × 100 mm in dimension, is cast and tested in the laboratory in compliance with the Indian standard code IS 456: 2000 [1] . The compressive strength of concrete, load carrying capacity, load versus deformation characteristics, stiffness and ductility relationship properties of the RC slabs was compared and discussed between control specimens and 0 to 50 percent of partially substituted RCA specimens.

The flexural behavior of Hollow core concrete slabs with different shape

Hollow slabs are slabs of reinforced concrete in which voids allow the concrete to be reduced in size. This type of slab results in reduced raw materials Consumption and increased insulating properties to achieve sustainability goals. This paper reported an experimental research program focused on the study of the bending behaviour of the elements of hollow slabs of normal-strength concrete. Three models of the one-way concrete slab were cast, It had dimensions of 1020 mm length, 420 mm width, and 100 mm thickness. The first model did not contain holes (solid) and the second model contained five circler opening holes with a 50 mm diameter, while the third model contained five square opening holes with 44 mm dimension, where the area of the second and third model were the same despite the difference in the shape of the opening. The results showed that the bearing capacity of the circular hollow core slab is higher by 12% compared to the square hollow core slab according to the type of voids and both of holes made the hollow core slab with a decrease in load capacity of 11% to 25% when compared to the solid slab. The solid slab has lower deflection value compared to the two hollow slabs whose weight is reduced by 23% compared to the solid slab.

Behaviour of non-ballast pre-stressed and precast track structures in high speed railway based on multiscale finite element model

In order to make further study on the mechanical property of CRTSIII type slab non-ballast track structures, which was self-designed in China, based on the method of the multiscale finite element model (FEM), the traditional FEM of slab non-ballast track structures was improved. The multiscale FEM of CRTSIII type slab non-ballast track structures was established based on the general finite element program ABAQUS. Then the comparative calculation was made between various FEMs, showing that the high solution precision, fast modelling speed and high solution efficiency could be obtained. Therefore, the multiscale FEM was suitable for the parametric study on mechanical behaviour of CRTSIII type slab non-ballast track structures, and then the key influence factor and constructions could be optimized.

Behavior of horizontal steel plate + studs connectors in a glulam-UHPC composite system: Experiment and analysis

Compared with conventional timber–concrete composite structures, glued laminated timber (glulam)–ultrahigh–performance concrete (UHPC) composite (GUCC) structures can remarkably reduce the deadweight and have small long-term deflection, good durability, and improved span capacity. Thus, this work designed a horizontal steel plate + stud (HS) connector with high stiffness and high shear capacity to ensure a reliable connection in the designed glulam–UHPC composite system and then investigated the structural behavior of the HS connector in the GUCC. In total, fifteen push–out specimens (in five groups with three replicates of each group) were fabricated and conducted a static load test. Effect of size of steel plate, the height-diameter ratio of stud, size of slab, and slab type (UHPC or NC) on the load-slip rules, shear stiffness, failure mode, and the shear capacity of HS connectors in GUCC were evaluated experimentally. The experimental results show that the average slip modulus and shear capacity of the HS connection ranges from 134.9 to 165.6 kN/mm and from 167.6 to 200.3 kN respectively. The primary failure mode of the structure comprises the shear failure of the glulam along the grain and the studs. Lastly, the empirical formula for calculating the load–slip relationship and the design formula for the shear capacity of the HS connection of GUCC systems are proposed. A comparison between the theoretical and experimental results reveals that the developed method has reasonable accuracy and can be used to guide the design of GUCC structures.

Experimental performance of novel cost – effective hybrid composite slabs made with cementitious composite

The present research investigation introduced a new design system for making cementitious structural elements. This study emphasizes on novel hybrid composite slab elements. The combination of newly formed hybrid fiber reinforced engineered cementitious composite (HECC) and self-consolidation concrete (SCC) was used to make slabs. The main objective of this study was to introduce novel kind of cost effective and greener HECC structural elements. In this study total 13 types of slabs were casted based on the 7 different cement mixes. To analyse the behaviour of slab specimens cracking loads, load-deflection behaviour, energy absorption capacity, flexural strength capacity, general failure pattern, ecological and economical aspects was recorded. The results from current experimental approach depicted that new composite slab system enhanced the flexural performance, energy absorption, service life and ductility of slab specimens. Construction of slabs with HC approach reduced the global warming potential (GWP), embodied energy (EE) and cost by 16.98%, 36.1%, and 67.53% respectively than full depth PVA fiber reinforced slab (HECC1). PI method indicated that HC-SL6 slab members most preferable for flexural strength capacity, ultimate load, environmental and economical aspects.

Research on the Bearing Performance of Prefabricated New Type Subway Track Slab with Basalt Fiber

Currently, most ballastless tracks in Chinese subways are traditional cast-in-situ concrete structures, which require long construction progress. In contrast, prefabricated ballastless tracks can greatly reduce the construction period. However, there are few theoretical and experimental analyses on the prefabricated new type of subway slab track. Hence, to study the mechanical properties of the new type of subway track slab, static bending crack tests of one standard slab track and nine prefabricated full-scale track slabs with basalt fiber were carried out in this paper. The influence of the reinforcement arrangement method and the basalt fiber content on the performance of the track slabs was studied. Results showed that with the increase in the basalt fiber content in the range of 0.1–0.3%, the load–strain curve growth rate increased, the stiffness decreased, and the flexural resistance reduced. All the specimens exhibited a linear portion (elastic) and then a nonlinear portion (plastic) followed by flexural failure. During the elastic stage, the basalt fiber helped to improve the rigidity of the track slab. During the plastic stage, the influence of the basalt fiber content on the failure load varied with different reinforcement arrangements. With the reinforcement arrangement F2 and 0.1% basalt fiber content, the specimen had the smallest load–strain curve growth rate and the best overall flexural performance and crack resistance, and its strain was 23.35 με at an elastic limit of 95 kN. The results can provide a reference for the design of the prefabricated slab ballastless track.

Resistance and serviceability assessment of innovative composite slab exposed to standard compartment fire

The resistance and serviceability of an innovative flat profile steel–concrete composite slab fabricated with fire-resistant weathering (FRW) steel are investigated in depth. A total of five composite slabs are subject to full-process standard fire tests, with another five slabs for comparative tests under room temperature. The full-process fire tests include 60-minute heating, 180-minute forced cooling, 24-hour natural cooling test. The heating and cooling curves are recorded and simulated by a series of logarithmic functions. Based on the test results, an exponential model is proposed in terms of deflection rebounding ratio to evaluate the capability of self-restoration after fire exposure. The residual loading ratio is defined to describe and assess the robustness of the slab after fire. Analysis results show that this new type of composite slab exhibits very strong resilience and robustness after exposure to standard fire. Finally, based on sufficient standard fire tests and shear-bond tests, the specific post-fire serviceability performances are formulated, including flexural capacity, shear-bonding action, shear capacity, limiting deflection under normal service condition. The post-fire assessment method is further proposed, characterizing with resilience, robustness and reusability in terms of deformation restoration, residual loading capacity and serviceability both under normal service and fire resistance limit conditions, respectively. These research findings are of great significance in assessing the resistance and serviceability of horizontal separating elements after timely fire extinguishing, proper repairing and rehabilitation.

Performance Evaluation of Ultra-Thin Wearing Course with Different Polymer Modified Asphalt Binders

Ultra-thin wearing course (UTWC) as an asphalt overlay is widely used in pavement maintenance for extending pavement service life. Researchers focused on improving and evaluating its performance, yet few researchers compare the performance of typical UTWCs. Moreover, some traditional asphalt mixture tests are improper for UTWC due to the thicknesses of UTWC, which is thinner than the traditional asphalt overlay. This study further evaluated the advantages and disadvantages of typical UTWCs. A series of tests were conducted to compare the comprehensive performance of three typical UWTC products, including SMA-10, Novachip-B, and GT-10. Moreover, this study improved the rutting test to evaluate its rutting performance more accurately. Rutting specimens of 20 mm thick and 50 mm thick composite specimens (20 mm UTWC + 30 mm Portland cement concrete slabs) were prepared. Two types of PCC slabs were used, including unprocessed PCC slabs and PCC slabs with preset cracks. The test results showed that Novachip-B showed the best water stability and weakest raveling resistance, while GT-10 showed the best fatigue and anti-skid performance. The rutting performance of UTWCs was reduced because of the influence of preset cracks. The rutting depth of GT-10 was only 60–90% of that of others, showing the comprehensive performance of GT-10 was better than that of others. These results provide a significant reference for the research and application of UTWC.

Experimental and theoretical study on flexural behaviour of a new UHPC sandwich slab

In this study, a new type of prefabricated ultra-high performance concrete (UHPC) sandwich slab is proposed, which is composed of UHPC layer at the top and bottom, short UHPC columns and extruded polystyrene foam board (XPS) in the middle layer. The load-bearing and thermal-insulation integrated sandwich slab shows much lower self-weight and less reinforcement than traditional concrete slab, which are very beneficial for construction of precast structures. This paper first presents a reasonable and reliable casting method for the new sandwich structure. Then four-point bending tests on five slabs are conducted to reveal their flexural performance. The investigated parameters include the thickness of the UHPC layer, reinforcement ratio, short column spacing and XPS layout. Test results demonstrate that this type of sandwich slab, with 4500 mm span length, 150 mm thickness and one-way simply supported condition, has excellent anti-cracking and flexural performance, which can sustain an additional uniformly distributed load more than 9 kN/m2 before cracking even without reinforcement. A small ratio of reinforcement 0.13% in the bottom layer can further improve the ultimate bearing capacity by 20% and ultimate deformation by 61%. Finally, the calculation methods of cracking load, peak load and stiffness are proposed, together with design suggestions for typical slab dimensions, which offers valuable guidance for practical engineering.

Molecular surveillance of non-O157 Shiga toxigenic Escherichia coli in selected chicken abattoirs and retail outlets in Osogbo, Osun State, Nigeria

Three selected chicken abattoirs and two retail locations were studied to determine the frequency of occurrence and profile for Shiga toxin-producing Escherichia coli (STEC) strains present in abattoirs and retail (frozen) chicken carcasses in Osun state, Nigeria. Samples were plated on Eosin Methylene Blue agar for the presence of E. coli. Furthermore, the isolates were confirmed serologically as non-O157 STEC using latex agglutination serotyping kit. Multiplex PCR was used to check for specific virulence factors in the isolated E. coli strains. The mean colony count results showed that effluent water samples from the Ikirun slaughter slab type abattoir were the highest at 25 cfu/ml. A post hoc comparison showed that this value was significantly higher than that of the slaughtering table at Oluode-1 (P = 0.04) and retail chicken meat samples at Igbona (P = 0.01). The results show that chicken abattoirs are poor reservoirs of STEC. Moreover, the results from this study showing that the stx2-producing strains that are more prone to cause hemolytic uremic syndrome is the predominant strain in the study area is worrisome. These results underscore the improper hygiene practices of the abattoir workers combined with inadequate waste management and biological waste disposal systems. It is recommended that regulatory bodies in this locality should focus on ensuring the upgrade of biological waste disposal from these abattoirs in order to limit spread of potentially virulent pathogens into the runoff and ground water.

Comparative Study of Conventional Slab, Flat Slab and Waffle Slab by using Finite Element Method

Abstract— The slab is the main component of the structure. There are different types of slab used in different structure and gives better appearance to the structure. In this project, three type of slab to be used. The comparative study of Conventional slab, flat slab, and waffle slab under seismic condition to be analyzed. An effort has been made to evaluate the study between Conventional slab, flat slab, and Waffle slab for G+10 story building. This type of slab has been analyzed and designed by ETABS software. The plan of waffle slab plan is done in such a way in order to accomplish better burden dispersion. The near investigation of waffle slab with flat Slabs and conventional slab and features the benefit waffle slab have over flat Slabs and conventional slab. The parametric studies comprise maximum lateral displacement, story drift, and axial forces generated in the column due to slab. Keywords— ETABS, Conventional Slab, Flat Slab, Waffle Slab, Story Displacement