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

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

Performance of Lightweight Foamed Concrete with Waste Clay Brick as Coarse Aggregate

AbstractPerformances of lightweight foamed concretes that are made from partial substitution of waste clay brick as coarse aggregate has been investigated in this study. The research aims were to identify the properties and characteristic of lightweight foamed concrete using waste clay brick as alternative materials to reduce the depletion of normal coarse aggregate from granite. Four different percentages of concrete mixtures using new coarse aggregate have been prepared that consist of 25%, 50%, 75%, and 100% waste clay brick. Foamed were injected into concrete mixture to produce lightweight concrete with appropriate proportions. The samples have undergone several testing including compression test, water absorption test, workability test and density test. From the results obtained, lightweight concrete that were produced with 25% substitution of waste clay brick showed the highest compressive strength of 25MPa with density of 1647kg/m3

A Properties of Municipal Solid Waste Incineration Fly Ash (IFA) And Cement Used in The Manufacturing of New Inventive Blended Cement

Municipal solid waste incinerator fly (IFA) ash is prone to accumulate high concentration heavy metals. Due to the increasing costs to treat remaining fly ash at the landfill, a lot of research has been done to recycle IFA. This study was focusing on the properties of IFA and cement as main raw materials in new inventive blended cement. The properties of blended cement were also being investigated. Properties of IFA and cement were examined through several test which includes density, specific gravity, X-Ray Fluorescence (XRF), Loss of Ignition (LOI) and through Toxicity Characteristic Leaching Procedure (TCLP) test. The density test and LOI test were also being done for the blended cement. From the tests for IFA and cement, it can be found that density the density of fly ash and cement that has been used for this study were found to be 0.76 g/cm3 and 3.67 g/cm3 respectively. Then, the specific gravity of fly ash and cement were 1.69 and 2.98, accordingly. XRF results shows that both materials have highest content of aluminium, silica and iron, as expected. LOI of fly ash and cement were found to be 17.33 % and 12.33 %, respectively. In terms of the leaching rates of heavy metals (Mn, Ni, Cd, Cr, Cu), only Cd leached at rate 2.39 mg/L, which is above the USEPA's regulatory level, 1.0 mg/L. 5 %, 10 % and 15 % of IFA was mixed with cement to produced blended cement. As the density of blended cement, it was found to be 1.12 g/cm3, 1.08 g/cm3 and 1.09 g/cm3 for each of 5 %, 10 % and 15 % of fly ash in blended cement

A Properties of Municipal Solid Waste Incineration Fly Ash (IFA) And Cement Used in The Manufacturing of New Inventive Blended Cement

Municipal solid waste incinerator fly (IFA) ash is prone to accumulate high concentration heavy metals. Due to the increasing costs to treat remaining fly ash at the landfill, a lot of research has been done to recycle IFA. This study was focusing on the properties of IFA and cement as main raw materials in new inventive blended cement. The properties of blended cement were also being investigated. Properties of IFA and cement were examined through several test which includes density, specific gravity, X-Ray Fluorescence (XRF), Loss of Ignition (LOI) and through Toxicity Characteristic Leaching Procedure (TCLP) test. The density test and LOI test were also being done for the blended cement. From the tests for IFA and cement, it can be found that density the density of fly ash and cement that has been used for this study were found to be 0.76 g/cm3 and 3.67 g/cm3 respectively. Then, the specific gravity of fly ash and cement were 1.69 and 2.98, accordingly. XRF results shows that both materials have highest content of aluminium, silica and iron, as expected. LOI of fly ash and cement were found to be 17.33 % and 12.33 %, respectively. In terms of the leaching rates of heavy metals (Mn, Ni, Cd, Cr, Cu), only Cd leached at rate 2.39 mg/L, which is above the USEPA's regulatory level, 1.0 mg/L. 5 %, 10 % and 15 % of IFA was mixed with cement to produced blended cement. As the density of blended cement, it was found to be 1.12 g/cm3, 1.08 g/cm3 and 1.09 g/cm3 for each of 5 %, 10 % and 15 % of fly ash in blended cement

VALIDATION OF SHEAR FAILURE ON BOLTED CONNECTION FOR NYATOH HARDWOOD

The lack of consideration of brittle failure by the Malaysian Timber Standard (MS544-5) in the design of bolted connections for local hardwood can be seen from the unacceptable under-design performance shown by the code. This makes the design output costly because of the increased use of steel materials due to either bigger bolt diameters or larger bolt quantities required. The current study was conducted to examine the effectiveness of the existing design equations for bolted connections in Nyatoh hardwood. This present study was to propose a set of optimised equations that can be used for the retrofit design of wall-diaphragm connections in unreinforced masonry buildings. The row shear failure observed in the tested bolted connections of Nyatoh hardwood was also reported. Ten different bolted connection configuration details in the manner of a steel-wood-steel arrangement were tested, which all had a single row bolted connection. By using the linear regression method in analysing the experimental data obtained, a calibration factor for optimising the Row Shear Model (RSM) equation was identified. From the comparisons made between the experimental results and the strength predictions given by both MS544-5 and RSM, it was found that the design strength calculated from MS544-5 was too conservative for predicting the bolted connection strength in Nyatoh hardwood, whereas the RSM predictions were acceptable and recommended

Effect of bolt configurations on stiffness for steel-wood-steel connection loaded parallel to grain for softwoods in Malaysia

Steel-wood-steel connection is widely seen in many applications, such as timber structures. The stiffness of steel-wood-steel connection loaded parallel to grain for softwoods originated from Malaysia was investigated in this study. Numerical models have been developed in ABAQUS to study the stiffness connection. Softwoods of Damar Minyak and Podo have been selected in this analysis. The comprehensive study focused on the effect of bolt configurations on stiffness. Numerical analysis is carried out and the developed model has been validated with the previous study. Further investigations have been made by using the validated model. From this model, numerical analysis of the stiffness values have been made for various bolt configurations, including bolt diameter, end distance, bolt spacing, number of rows and bolts and edge distance. The result shows that the stiffness of bolted timber connections for softwood depends on the bolt diameter, number of rows and bolts, end distance and edge distance. Based on the result, stiffness increased as the diameter of the bolt, end distance, number of rows and bolts and edge distance increased. It is also discovered that the stiffness equation in Eurocode 5 (EC5) is inadequate as the equation only considered parameters which are wood density and bolt diameter. Other connection parameters such as geometry are not considered in the EC5 equation

The Effect of Particle Size on the Mechanical Properties of Alkali Activated Steel Slag Mortar

With the rapid development of industry, abundant industrial waste has resulted in escalating environmental issue. Steel slag is the by-product of steel-making and can be used as cementitious materials in construction. However, the low activity of steel slag limits its utilization. Much investigation has been conducted on steel slag, while only a fraction of the investigation focuses on the effect of steel slag particle size on the properties of mortar. The aim of this study is to investigate the effect of steel slag particle size as cement replacement on properties of steel slag mortar activated by sodium sulphate (Na2SO4). In this study, two types of steel slag, classified as fine steel slag (FSS) with particle sizes of 0.075mm and coarse steel slag (CSS) with particle sizes of 0.150 mm, were used for making alkali activated steel slag (AASS) mortar. Flow table test, compressive strength test, flexural strength test and UPV test were carried out by designing and producing AASS mortar cubes of (50 × 50 × 50) mm at 0, 10%, 20% and 30% replacement ratio and at 0.85% addition of Na2SO4. The results show that the AASS mortar with FSS possess a relatively good strength in AASS mortar. AASS mortar with FSS which is relatively finer shows a higher compressive strength than CSS up to 38.0% with replacement

The Stiffness of Steel-Wood-Steel Connection Loaded Parallel to the Grain

In Eurocode 5, the stiffness equation for bolted steel-wood-steel is stated as a function of wood density and fastener diameter only. In this research, an experimental study on various configurations of tested bolted steel-wood-steel (SWS) connections has been undertaken to predict the initial stiffness of each connection. In order to validate the Eurocode 5 stiffness equation, tests on 50 timber specimens (40 glued laminated timbers and 10 laminated veneer lumbers (LVL)) with steel plates were undertaken. The number of bolts was kept similar and the connector diameter, timber thickness, and wood density were varied. The results obtained in the experimental tests are compared with those obtained from the Eurocode 5 stiffness equation. From the analysis, it is signified that the stiffness equation specified in Eurocode 5 for bolted SWS connections does not adequately predict the initial stiffness. The results from Eurocode 5 stiffness equation are very far from the experimental values. The ratio of stiffness equation to experimental results ranges from 3.48 to 4.20, with the average at 3.77, where the equation overpredicted the experimental stiffness value for the connection. There is a need to consider or incorporated other parameters such as geometric configurations in Eurocode 5 stiffness equation to improve the ratio with the experimental data

Computer simulations of end-tapering anchorages of EBR FRP-strengthened prestressed concrete slabs at service conditions

This article examines numerically the behavior of prestressed reinforced concrete slabs strengthened with externally bonded reinforcement (EBR) consisting of fiber-reinforced polymer (FRP) sheets. The non-linear finite element (FE) program Abaqus® is used to model EBR FRP-strengthened prestressed concrete slabs tested previously in four-point bending. After the calibration of the computational models, a parametric study is then conducted to assess the influence of the FRP axial stiffness (thickness and modulus of elasticity) on the interfacial normal and shear stresses. The numerical analysis results show that increasing the thickness or the elastic modulus of the FRP strengthening affects the efficiency of the FRP bonding and makes it susceptible to earlier debonding failures. A tapering technique is proposed in wet lay-up applications since multiple FRP layers are often required. It is shown that by gradually decreasing the thickness of the FRP strengthening, the concentration of stress along the plate end can be reduced, and thus, the overall strengthening performance is maximized. The tapering is successful in reducing the bond stress concentrations by up to 15%, which can be sufficient to prevent concrete rip-off and peel-off debonding failure modes. This article contributes towards a better understanding of the debonding phenomena in FRP-strengthened elements in flexure and towards the development of more efficient computational tools to analyze such structures