Slab Reinforcement Research Articles

An Analysis of The Apartment's Tamansari Skylounge Halfslab Connection as a Diaphragm (Case Study : Padang Seismic Load)

Precast concrete is used in the Tamansari Skylounge Balikpapan Apartment's construction. The diaphragm is a slab that transmits lateral forces to the vertical element. This structure has a topped diaphragm as its diaphragm type. The goal of this analysis is to determine how seismic forces are distributed throughout a building using the seismic zone of Padang, to test the half-strength slab's during lifting, before and after a composite, to determine how deformation differs when a diaphragm is constrained, and to conduct research to strengthen the connection of the diaphragm's critical area to the building. The steps in data processing include analyzing the structure using SAP 2000, gravity load analysis based on PPIUG 1987, seismic load analysis based on SNI 1726:2012, connection diaphragm analysis based on NEHRP Seismic Design Technical Brief No. 3, normalizes and shear stress analysis on half slabs meeting between half slabs with topping based on Tension Material Analysis, and analysis of reinforced concrete structures based on SNI 2847: 2013. According to the analysis's findings, the 1B floor has the maximum seismic force at 19205269,17 N. The Half Slab reinforcement becomes ϕ10-150 with the added seismic load, and deformation with a diaphragm constraint is considerably less than without one. One piece of 12 mm diameter reinforcement with a shear connector is used for each square meter of the important diaphragm region.

ANALISIS PERENCANAN STRUKTUR ATAS GEDUNG PERPUSTAKAAN DAN ARSIP KABUPATEN LIMA PULUH KOTA

Development is priority in improving quality of Human Resources. Library is one of facilities that support the development of science and information. Books are source of knowledge that make someone understand science. The goal that the author wants to achieve is to obtain the results of the Evaluation of the Library and Archives Building of Lima Puluh Kota Regency with the principle of ductility to create a building that is safe, comfortable and resistant to earthquakes. From the results of this structural analysis, the reinforcement structure is obtained from author's analysis. The results obtained that the material used is steel fy = 300 MPa and concrete quality fc' = 24.9 MPa. For reinforcement of floor slabs, reinforcement is used for the direction of x = 13 – 150, while the direction of y = 13 – 150. Column planning uses steel fy = 400 Mpa and concrete quality fc' = 24.9 MPa with a column size of 50 cm x 50 cm . While the design of the beam using steel quality fy = 300 Mpa and concrete quality fc' = 24.9 Mpa with sizes for main beam 50cm x30cm, Joist 1 45cm x25cm and joist 2 30cm x25cm.Keywords: Construction, building, ductile

Influence of adding short carbon fibers on the flexural behavior of textile-reinforced concrete one-way slab

The application of textile reinforcement to the tension zone of the reinforced concrete slabs as a means to enhance flexural capacity has been investigated by researchers in the past. However, the effectiveness of adding short carbon fibers as internal reinforcement in the textile-reinforced concrete one-way slab needs to be studied. The paper presents the experimental research conducted on four full-scale (1500×500×50) mm one-way slabs. An innovative Polyacrylonitrile (PAN) textile grid was used as internal reinforcement in combination with short carbon fibers. The first one consists of fine-grained concrete and short carbon fibers. Two textile-reinforced RC slabs have eight layers of fabric (textile-reinforced concrete (TRC) 8 L) with two percentages of short carbon fiber (0.264% and 0.528%), and one reference textile-reinforced concrete slab without short carbon fiber was fabricated to investigate the flexural behavior under a four-point loading system. The findings indicate that TRC + short carbon fiber showed significantly improved flexural capacity, load-deflection, and load-concrete strain behaviors compared with TRC. The new TRC+ 0.264% short carbon fibers (SCF) and TRC+ 0.528%SCF improved the load-bearing capacity by about 24.19% and 31.56%, respectively, as compared with TRC. Also, the intensity of the crack pattern was measured to compare the ductility of TRC+ short carbon fiber to that of traditional TRC.

PERENCANAAN PEMBANGUNAN GEDUNG BARU BALAI NIKAH DAN MANASIK HAJI KUA KECAMATAN AUR BIRUGO TIGO BALEH KOTA BUKITTINGGI

: The structure of this building uses reinforced concrete construction. The structure analysis goes through stages starting from Preliminary Design, structural loading, earthquake loading using the latest method, namely the response spectrum, analysis of the forces that occur in the structure using SAP2000 Version 20 by selecting the network system structure system (Grid System). The materials used are K-250 quality concrete (f'c = 20.75 MPa), screw reinforcement (fy = 400 MPa), plain reinforcement (fy = 240 MPa). For floor slab reinforcement, reinforcement is used for the x = 10-150 direction, while the y direction = 10-170. The column design uses steel quality fy = 400 MPa and concrete quality fc' = 20.75 MPa for columns 1 and 2 with a size of 35cm x 35cm. For the design of the beam using steel quality fy = 400 MPa and concrete quality fc' = 20.75 MPa with beam size 1 30cm x 50cm and beam 2 25cm x 45cm. And for stirrup reinforcement using steel quality fy = 240 MPa.Keywords: Preliminary Design, SAP2000 Analysis, Foundation, Loading ReinforcedConcrete, Reinforcement

Research on Structural Performance of Hybrid Ferro Fiber Reinforced Concrete Slabs.

Reinforced concrete structures, particularly in cold areas, experience early deterioration due to steel corrosion. Fiber-Reinforced Concrete (FRC) is an emerging construction material and cost-effective substitute for conventional concrete to enhance the durability and resistance against crack development. This article examines the structural performance of hybrid ferro fiber reinforced concrete slabs (mix ratio of mortar 1:2) comprising silica fume, layers of spot-welded mesh and different ratios of polypropylene fibers. The ferrocement slabs are compared with a conventional Reinforced Cement Concrete (RCC) slab (mix ratio of 1:2:4). The experimental work comprised a total of 13 one-way slabs, one control specimen and three groups of ferrocement slabs divided based on different percentages of Poly Propylene Fibers (PPF) corresponding to 0.10%, 0.30% and 0.50% dosage in each group. Furthermore, in each group, the percentage of steel ratio in ferrocement slabs varied between 25% and 100% of the steel area in the reinforced concrete control slab specimen. For evaluating the structural performance, the observation of deflection, stress-strain behavior, cracking load and energy absorption are critical parameters assessed using LVDTs and strain gauges. At the same time, the slabs were tested in flexure mode with third point loading. The experimental results showed that the first cracking load and ultimate deflection for fibrous specimens with 0.5% fiber and 10% silica fume increased by 15.25% and 13.2% compared with the reference RCC control slab. Therefore, by increasing the percentage of PPF and steel wire mesh reinforcement in the ferrocement slab, the post-cracking behavior in terms of deflection properties and energy absorption capacity was substantially enhanced compared to the RCC control slab.

Оптимизация решения фундамента путем проведения натурных экспериментальных исследований взаимодействия плиты с податливым основанием

Article considers the case of optimizing design solution for foundation of a 10-storey residential building on sandy soils. Optimization was achieved through experimental work with 2*2*0,2 m reinforced concrete slabs and 5000 cm2 stamps. During slabs testing slab settlements, in concrete and reinforcement, as well as contact pressure under slab were measured. During stamps testing displacements of the stamp and surrounding soil were measured at 21 points. As a result of the tests deflection slab mode, slab-soil contact stresses, changes in radius of curvature, relative deformation of concrete and reinforcement in upper and lower parts of the slab during loading were obtained. Results of experimental data made it possible to select a foundation model, which was later used for foundation design. Recommendations are given for determining soil deformation characteristics, modeling soil-plate interaction, as well as economic efficiency of foundation design solution.

Fatigue Analysis of CFRP-Reinforced Concrete Ribbed Girder Bridge Deck Slabs.

This study aims to improve the operational safety of reinforced concrete-ribbed beam bridge decks and prolong their service life by performing fatigue analysis of deck slabs reinforced with carbon-fiber-reinforced polymers (CFRP) and other materials. Based on a 16-m-span ribbed girder bridge, five test beams were designed: three reinforced (with CFRP cloth, CFRP mesh, and strip steel plates) and the remaining unreinforced. To simulate the real force of the bridge deck slabs, a PLS-500 electro-hydraulic servo dynamic and static test system was used and static load failure (monotonic graded loading) and fixed-point constant-amplitude fatigue loading tests (fatigue load of 0.515, loading frequency of 5 Hz) were performed. The main fatigue crack appeared when the number of load cycles exceeded 90% of the fatigue life. In the middle of fatigue, the reinforcement material can reduce the deterioration value of the bridge deck by approximately 50%. When it is reinforced at the cumulative damage degree of 0.4, its fatigue life extends by approximately 53.3–78.9%. The fatigue life of the bridge deck slabs reinforced with CFRP cloth or mesh was 22.1–25.6% more than that of those reinforced with strip steel plates. CFRP cloth is best suited for the reinforcement of bridge deck slabs.

Structural integrity of composite floors in fire: A comparison of two large-scale experiments with varying slab reinforcement

This paper presents a comparison of two compartment fire experiments performed on the 9.1 m × 6.1 m composite floors using a full-scale two-story steel gravity frame to study the influence of slab reinforcement on the overall structural integrity. The floor specimens were designed to achieve a 2-h fire rating but had dissimilar slab reinforcement. The Test #1 specimen had steel wire reinforcement of 60 mm2/m width as the minimum permitted in the United States practice whereas the Test #2 specimen was reinforced with deformed steel bars (230 mm2/m) determined by incorporating tensile membrane action. The Test #1 specimen exhibited mid-panel slab integrity failure before reaching the specified fire rating period. However, the Test #2 specimen exhibited much smaller concrete cracks until it was heated up to 131 min and retained the post-fire residual strength at least two times greater than the design demand at ambient temperature. This unique large-scale testing demonstrated that the appropriate slab reinforcement scheme can delay the vertical deflection of the heated composite floor and maintain the structural integrity at large vertical displacements over a longer duration of fire exposure.

Experimental and analytical behavior of one-way fiber foamed concrete slabs reinforced with/without glass fiber grid under 4-point flexural test

PurposeThe primary objective of this study is to produce one-way slabs made of LWFC with low density and sufficient compressive strength suitable for structural purpose then investigate their flexural behavior under various types of reinforcement and thickness of the slab and the influence of addition of PP fibers reinforcement on the mechanical behavior of reinforced concrete slabs. The specimens were tested using four-point loading. The results concerning load capacity, deflection and failure mode and crack pattern for each specimen were obtained. Also, an analytical investigation of PP fiber and GFG contribution on the flexural behavior of foamed concrete slabs is studied to investigate the significant role of PP fiber on the stress distribution in reinforced foam concrete and predict the flexural moment capacity.Design/methodology/approachThe materials used in this study are cement, fine aggregate (sand), water, PP fibers, foaming agent, chemical additives if required, steel reinforcing rebars and glass fiber grid. The combination of these constituent materials will be used to produce foamed concrete in this research Then this study will present the experimental program of one-way foamed concrete slabs including slabs reinforced with GFR grids and another with steel reinforcements. The slabs will be tested in the laboratory under static loading conditions to investigate their ultimate capacities. The flexural behavior is to the interest of the slabs reinforced with GFR grids reinforcements in comparison with that of one with steel reinforcing rebars. Three groups are considered. (1) Group I: two slabs of PP fiber foamed concrete with minimum required reinforcements. (2) Group II: two slabs of PP fiber foamed concrete with glass fiber grids. (3) Group III: two slabs of PP fiber foamed concrete with the minimum required reinforcements and glass fiber grids.FindingsThe experimental results proved the effectiveness and efficiency of this the new system in producing a low density of concrete below 1900 kg/m3 had a corresponding strength of about 17 MPa at least. Besides, the presence of PP fibers had a noticeable improvement on the flexural strength values for all the examined slabs. It was found that the specimens reinforced with steel reinforcement mesh carried higher flexural capacity compared to these reinforced with GFG only. The specimens reinforced with GFG exhibited the lowest flexural capacity due to GFG separation from the concrete substrate. Also, an analytical investigation to predict the flexural strength of all tested specimens was carried out. The analytical results were agreed with the experimental results. Therefore, LWFC can be used as a substitute lightweight concrete material for the production of structural concrete applications in the construction industries today.Research limitations/implicationsFoamed concrete is a wide field to discuss. To achieve the objectives of the project, the study is focused on the foamed concrete with the following limitations: (1) because the aim of this research is to produce foamed concrete suitable for structural purposes, it is decided to produce mixes within the density range 1300–1900 kg/m3. (2) Simply-supported slabs are of considered. (3) This study also looks out by using GFR and without it.Originality/valueThe main objectives of this study were producing structural foamed concrete slabs and investigate their flexural response for residential uses.

Evaluating the perception of structural defects during implementation of RC T-beams

Most defects during construction projects are due to human errors which happen due to poor workmanship. This study involved 8 simply supported RC T-beams subjected to uniformly distributed load at both-edges of slab. The investigated parameters were the effect of malposition of slab reinforcement, unequal configuration of slab reinforcement and change in bar diameter of slab reinforcement. The experimental results showed that; malposition of slab reinforcement leads to a lower load carrying capacity of the slab and consequently flexural resistance decreased and slab deflection increased. The irregularity of the reinforcing bars in concrete slab affected the load carrying capacity of T-beam. Well-arranged distribution of reinforcement improves the ductile behavior of slab and reduced value of deflections at failure. Using reinforcing steel bars with diameters higher than 8mm in the reinforcement helped the slab to withstand more loads. The use of 10mm diameter in reinforcement of the slab enhances the serviceability of T-beams.

Experimental Investigation on the Effectiveness of Truss-Shaped Punching Shear Reinforcement in Flat Slab

The use of reinforced concrete flat slabs in building construction increases the floor-to-floor clearance, expedites site operations, and offers aesthetically rewarding features. However, punching shear failure in a flat slab is brittle in nature and can be potentially catastrophic. Many studies have been conducted to improve the punching shear capacity of flat slabs but some of the proposed punching shear reinforcements were complicated and costly. This research aimed to evaluate the effectiveness of a simple and cost-effective; truss-shaped punching shear reinforcement embedded in a 1200 mm × 1200 mm × 175 mm thick flat slab specimen. Three types of truss-shaped punching shear reinforcements were prepared. All specimens were supported at the edges and subjected to gravity load tests. The results showed that the introduction of truss-shaped punching shear reinforcement increased the punching shear capacity in the range of 7.71% to 21.47%. The maximum deflection of these specimens exhibited an insignificant increase compared to the control specimen, suggesting that punching failure governed the ultimate behavior. The additional strength offered by truss-shaped punching shear reinforcement makes flat slabs as a construction material more appealing because they allow them to withstand higher design loads.

Impact of elevated temperature on the behavior of full-scale concrete bridge deck slabs reinforced with GFRP bars

The fiber reinforced polymer (FRP)-concrete composite bridge deck is expected to be a competitive alternative to the reinforced concrete bridge deck owing to its great durability, low weight, and high loading efficacy. The advantages of glass fiber reinforced polymer (GFRP) reinforcement in relation to heated damaged full-scale concrete bridge deck slabs encourage the extension of knowledge regarding the possibilities of combining the GFRP and heated damaged concrete to use the synergy of benefits that can be achieved in the construction and/or rehabilitation of bridges. This study presents a three-dimensional nonlinear finite element analysis (NLFEA) simulating the response of full-scale concrete bridge deck slabs reinforced with GFRP bars. A control slab model was developed initially and properly calibrated and validated against published independent experimental results. A parametric study was then conducted through creating twenty-four NLFEA models with different parameters: type of reinforcement (GFRP and steel), bottom transverse reinforcement ratio (ρ of 0.38, 0.46, and 0.57), and elevated temperature (20 °C, 100 °C, 200 °C, and 300 °C). The GFRP bars reinforcement of bridge deck slabs had superior effects on the ultimate load, elastic stiffness, post cracking stiffness, elastic energy absorption and post cracking energy and a little impact on ultimate deflection compared with steel reinforcement and the efficiency of GFRP bars increased with the heated damage level. Punching shear failure with a very similar cracking pattern was observed almost in all slabs and the bottom transverse reinforcement ratio is the main parameter affecting the tensile strains.

Perforated board shear connector for timber-concrete composites

ABSTRACT Timber-concrete composites systems offer major structural advantages, as well as additional benefits in terms of sustainability in comparison with only-timber or only-concrete solutions in building work. This paper describes the behaviour of shear connections for a new and simple construction system. It is based on the transmission of shear forces between the two layers of the system through perforations in the wooden boards, without the necessary collaboration for additional connecting elements (fasteners, adhesive or notches). Tests were performed to analyse how the behaviour of the shear connectors was affected by the arrangement of the boards (single or separated), the type and distribution of the perforations and the use of slab reinforcement. The experimental results indicate that this solution has high strength values, with very high service stiffness and ductile failure when at ultimate state, which enables a high level of composite action for connection design. The stiffness coefficient varies from 283.5–887.7 kN/mm per metre. The test pieces with separated boards and reinforcement bars showed the best results, regardless of the size and arrangement of the holes in the boards.

MONOLITHIC REINFORCED CONCRETE STRUCTURES WITH POST-TENSIONED ROPES

Currently in Ukraine the use of monolithic structures with post-tensioned ropes, which is better known as the technology of "post-tension", and in domestic construction practice - as post-tensioned reinforced concrete structures with reinforcement tension "on concrete". Ropes are mainly used as tension reinforcement in such constructions. 
 The article presents the main idea of post-tensioned monolithic reinforced concrete structures, presents the experience of using this technology in the construction of public buildings in Ukraine. Such designs have their advantages and scope. Sometimes such designs, in fact, have no other alternative. Therelevance of the study lies in the spread of the use of monolithic structures with post-tensioned ropes, the need to study such structures and the lack of regulatory documents for design. There are also examples of reinforcement of beams and slabs in slab structures and the main advantages of using posttension ropes in monolithic reinforced concretestructures on sites built in Ukraine.

Anchorage of shear reinforcement in beams and slabs

Anchorage of shear reinforcement, such as links or stirrups, can be performed by providing hooks, bends or heads at their ends, by welding transverse reinforcement or by closing open stirrups with pins. Hooks and bends, also used to enhance the anchorage of flexural reinforcement at the end regions of beams and slabs, have often been preferred because of their simple and cost-effective production. Such anchorages present nevertheless several peculiarities that shall be accounted for. They are relatively sensitive to their detailing (mandrel diameter, length of the tail segment between bar end and bent region) as well as to the cracking state of the surrounding concrete. Also, brittle failures can occur due to spalling of the concrete cover in case of bars near to a free surface.The anchorage with hooks and bends is currently still widely designed according to old detailing rules, based on the results of tests performed in many cases with materials whose properties are significantly different than those of nowadays. Also, no mechanical models are available for a consistent verification and detailing, acknowledging the different potential failure modes and their interaction with the surrounding concrete. In an effort to provide a consistent approach to its design and verification, this paper presents an investigation addressed at understanding the mechanical response and performance of bend and hook anchorages. To that aim, the results of an experimental programme performed with state-of-the-art instrumentation are introduced. By means of analysis of Digital Image Correlation and Fibre-Optic Measurements, the complete transfer of forces is analysed under different circumstances. On that basis, a consistent mechanical model is developed and validated, also reproducing a large variety of tests found in the literature. The paper introduces eventually several practical considerations on the activation of shear reinforcement in beams, and the level of performance required at its anchorages.

Comparison of the Flexural Behavior of High-Volume Fly AshBased Concrete Slab Reinforced with GFRP Bars and Steel Bars

Fiber-reinforced polymer (FRP) rods are advanced composite materials with high strength, light weight, non-corrosive properties, and superior durability properties. Under severe environmental conditions, for concrete structures, the use of glass-fiber-reinforced polymer (GFRP) rods is a cost-effective alternative to traditional steel reinforcement. This study compared the flexural behavior of an OPC concrete slab with a high-volume fly ash (HVFA) concrete slab reinforced with GFRP rods/steel rods. In the fly ash concrete slabs, 60% of the cement used for casting the slab elements was replaced with class F fly ash, which is emerging as an eco-friendly and inexpensive replacement for ordinary Portland cement (OPC). The data presented include the crack pattern, load–deflection behavior, load–strain behavior, moment–curvature behavior, and ductility of the slab specimens. Additionally, good agreement was obtained between the experimental and nonlinear finite element analysis results using ANSYS 2022-R1. The study also compared the experimental moment capacity with the most commonly used design standard ACI 440.1R-15. This investigation reveals that there is a huge potential for the utilization of GFRP rods as reinforcement in fly ash concrete slabs.

Fatigue Performance of Rib Beam Bridge Slabs Reinforced with Polyurethane Concrete Based on the Damage Theory

In this paper, the rib beam bridge slabs were taken as the research object. Static load and fatigue tests were carried out on the benchmark bridge slabs to determine the ultimate load capacity and fatigue life of the bridge slabs. Then, the bridge slab was pre-damaged and reinforced with polyurethane concrete. A fatigue test was carried out on the reinforced bridge slab to study the fatigue performance. Based on the damage theory, the fatigue damage reinforcement finite element models of the bridge slabs under different damage degrees were established. The fatigue performance of the reinforced bridge slabs was systematically studied. The results show that the fatigue damage of the reinforced bridge slab developed in stages. Compared to the unreinforced bridge slab, the fatigue damage of the reinforced bridge slab was significantly reduced at each stage. According to the least square method and numerical analysis results, a residual-bearing-capacity model including damage degree and fatigue cycles of the reinforced bridge slabs is proposed, which can be used as a reference in bridge slab reinforcement design.

Post-punching failure mechanism and resistance of flat plate-column joints with in-plane constraints

Flat plate-column joints with in-plane constraints exhibit a suspension mechanism under large deformations after punching shear failure, which significantly affects the progressive collapse behavior of the entire flat plate structural systems. However, in-plane constraints were ignored in the existing tests by which the suspension mechanism could not be exhibited and consequently the post-punching resistance was significantly underestimated. To fill this gap, a static pushdown test was conducted on eight flat plate-column joints with in-plane constraints until their post-punching resistances being completely lost. The influences of the punching directions and the structural parameters including slab thickness, reinforcement amounts and arrangement of flexural reinforcement on the post-punching failure mechanism were analyzed. An analytical method for calculating the post-punching strength was proposed and validated by the test results. The contributions of each layer of reinforcement to the post-punching resistance were also quantified.

Determining features of the deformed state of reinforced concrete beams of road bridges when strengthening the span structures

The technology of repairing reinforced concrete bridges typically involves closing traffic on one half of the structure and performing work on it when it is possible to move vehicles on the second part of this structure. The main process of interest to practitioners in terms of hardening concrete, which occurs in the beams of a span structure during the passage of a temporary moving load, is deformation. By the time the cement of freshly laid concrete of the overhead reinforcement slab is hardened, it is necessary to create the necessary conditions for this (temperature, humidity, immobility over time, etc.). Before concrete acquires strength, movements arising in the span structure cause the destruction of cement stone at the formation stage. It is necessary to investigate the presence of deformations, as well as their impact on the impossibility of forming a homogeneous structure of concrete and its adhesion to reinforcing elements that combine the existing slab with the new one. This study has established deformations induced by a temporary load from 1.61 to 5.83 mm, which have a negative impact on the process of solidification of concrete in the reinforcement slab for a span structure during the repair of a motorway bridge. The three-dimensional models were calculated by simulating a bridge of the M-04 highway. The results underlie the conclusions that the technology of repair work does not take into consideration the required conditions for high-quality concrete strength acquisition in an additional slab. The study results established that operations on concreting an additional overhead reinforcement slab in the presence of vibrational effects exerted by the temporary load on the span structure cannot be performed because of the destruction of concrete at the hardening stage. Given the above issue, several ways to address it have been devised and analyzed; the best of them is recommended

НЕКОТОРЫЕ СПОСОБЫ УСИЛЕНИЯ ФУНДАМЕНТНЫХ ПЛИТ

Various ways of strengthening foundation slabs are analyzed in relation to cases when, after the construction of foundation slabs, as a result of project adjustments, the load on them increases. An example of the implementation of the reinforcement of the foundation plate in the case of an increase in the number of storeys of the building from 10-14 floors to 17 is given. The effectiveness of various ways of strengthening foundation slabs is investigated by the example of the regional children’s clinical hospital under construction in Tver. The methods of reinforcement of foundation slabs are conditionally divided into two groups within the framework of constructing a finite element computational model. The first group includes methods that compensate for the lack of upper stretched reinforcement of the foundation plate by sticking on the surface of problem areas of steel or carbon fiber tapes. The second group includes a method that redistributes bending forces in the foundation plate from more loaded to less loaded sections. Methods of modeling of sub-columns in the computing environment of the LIRA-CAD software complex are investigated