Top PDF Structural behaviour of precast lightweight concrete sandwich panel under eccentric load: an overview

Structural behaviour of precast lightweight concrete sandwich panel under eccentric load: an overview

Structural behaviour of precast lightweight concrete sandwich panel under eccentric load: an overview

Lian (1999) carried out a test program to study the ultimate limit behaviour of reinforced concrete sandwich panels under axial and eccentric loads. 4 specimens were cast and tested. The panels were 1.5m long, 0.75m wide and 40-50-40 mm construction, i.e. 40 mm thick concrete wythes with a 50 mm thick insulating layer. The ultimate load capacity for pure axial loaded panels was computed using expressions for design of solid reinforced walls. It was reported that some of the expressions applicable to solid walls could not be directly applied to the sandwich panel. However, it may also be noted that the slenderness ratio (H/t) is an important factor influencing the load bearing capacity of axial loaded panels, and the number of the tested panels was also small, no generalised inferences could be drawn.
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Structural behaviour of precast lightweight foamed concrete sandwich panel under axial load: an overview

Structural behaviour of precast lightweight foamed concrete sandwich panel under axial load: an overview

Based on the previous research, can be seen that the research of PLFP is still limited and there are still many weakness that arise such as the research done by Lian (1999). This study discussed about the ultimate limit behaviour of reinforced concrete sandwich panels under axial and eccentric loads. However, the numbers of the tested panels was also so small which is only 4 specimens were cast and tested to carry out the result of the research, , no generalised inferences could be drawn. Compared to the author research, the number of tested panels are 8 specimens which is we can compare the result by find the average of the result thus, to obtain the precise and accurate results. The ultimate load capacity for pure axial loaded panels was computed using expressions for design of solid reinforced walls. It was reported that some of the expressions applicable to solid walls could not be directly applied to the sandwich panel.
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Structural Behaviour of Precast Lightweight Foamed Concrete Sandwich Panel under Axial Load: An Overview

Structural Behaviour of Precast Lightweight Foamed Concrete Sandwich Panel under Axial Load: An Overview

Based on the previous research, it is proved that the research of PLFP is still limited and there are still many weaknesses that arise such as the research done by Lian [12]. This study discussed about the ultimate limit behavior of reinforced concrete sandwich panels under axial and eccentric loads. However, the numbers of the number of tested panels was small which is only 4 specimens; therefore, no generalized inferences could be drawn. The author will test sixteen (8 by 2) panel specimens with single shear connectors and the results will be compared with the results from similar panels with double shear truss connectors tested by previous researchers. By testing higher numbers of specimen more accurate results will be recorded from the average result obtained.
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Structural behaviour of precast lightweight foamed concrete sandwich panel (PLFP) with shear truss connectors

Structural behaviour of precast lightweight foamed concrete sandwich panel (PLFP) with shear truss connectors

This study is aimed to provide information about the structural behaviour of PLFP with shear connectors. It is able to get a clear and deeper insight on the structural behaviour and failure mechanisms of the PLFP with single and double shear truss connectors under axial and push off loading. The results from this study are very important to assist the design of the PLFP to be used as a precast wall system especially the ultimate load carrying capacity and failure mechanism. An empirical equation is proposed in this study which is able to predict the ultimate load carrying capacity of PLFP under axial loading. The equation can be used to predict the maximum load of sandwich in non-linear behaviour after the service load.
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The structural behaviour of precast lightweight foamed concrete sandwich panel as a load bearing wall

The structural behaviour of precast lightweight foamed concrete sandwich panel as a load bearing wall

Lee et al. (2006) in their paper described an ongoing project to demonstrate an affordable, safe, and energy-efficient housing technology based on expanded polystyrene (EPS) foam panels with a cementitious coating. In this system, the EPS was acting as the core while the cellulose fiber cement board panel was acting as the facings of the panel. The EPS core layer was embedded with the wire trusses which were connected to the wire mesh that enclosed the EPS layer. The cement board facings were screwed to the surface of the EPS layer. The concepts being described are as shown in Figure 2.6, Figure 2.7 and Figure 2.8. Preliminary tests were conducted to analyze the costs, to simulate seismic forces, to conduct the test against environmental conditions, and to build pilot houses.
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Study on precast lighweight foamed concrete sandwich panel (PLFP) connection under flexural load

Study on precast lighweight foamed concrete sandwich panel (PLFP) connection under flexural load

In Malaysia, industrialized building system (IBS) had started many decades ago but until now it is still experimenting with various prefabricated method. The governments of Malaysia also encourage the use of IBS and insist that the office building projects shall have at least 70% IBS component. To encounter demands from the growing population and migration of people to urban areas in this country, alternative construction method is required to provide fast and affordable quality housing and environmental efficient. One of the alternatives that already been studied is Precast Lightweight Sandwich Panel. Before we can introduce new innovative construction method, the construction details are an important factor in building design. There has not been any study on Precast Lightweight Foamed Concrete Sandwich Panel (PLFP) connection.Connection is important to transfer loads and also for stability. With regard to the structural behaviour, the ability of the connection to transfer forces is the most essential property. Every aspect of the panel behavior must be analysied. This study will only focus on analyzing the performance of two small scale PLFP walls with U-bent bars connection under bending in term of load-displacement relationship, modes of failure and its ultimate load capacity when connected.
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The structural performance of precast lightweight foamed concrete panel (PLFP) with double shear connectors

The structural performance of precast lightweight foamed concrete panel (PLFP) with double shear connectors

Kabir (2005) investigated the structural performance of shotcrete lightweight sandwich panel with compressive strength of 12 MPa and tensile strength of 1.2 MPa under shear and bearing loads. The sandwich panel consisted of shotcrete wythes which enclose the polystyrene core. Three specimens are provided for horizontal bending tests, each sandwich panel is 300 cm long and 100 cm wide, the upper and lower concrete wythes are 6 and 4 cm thick, respectively. It was reinforced by the diagonal 3.5 mm cross steel wires welded to the 2.5 mm steel fabric embedded in each wythe as shown in Figure 2.2. Tests for flexural and direct shear loading were carried out based on ASTM E-72 and ASTM 564, respectively. From the experiment result, it was found that the crack propagates to the upper layer, at 1200 kg load. The bottom mesh was yielded and the crushing of concrete causes the instability of the panel. The maximum load was recorded at 2200 kg. Table 2.3 shows the ultimate loads and their corresponding displacement of slabs for the horizontal flexural load test.
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OVERVIEW OF EMPIRICAL EQUATION PREDICTION FOR ULTIMATE AXIAL LOAD OF PRECAST LIGHTWEIGHT FOAMED CONCRETE SANDWICH PANEL (PLFP)

OVERVIEW OF EMPIRICAL EQUATION PREDICTION FOR ULTIMATE AXIAL LOAD OF PRECAST LIGHTWEIGHT FOAMED CONCRETE SANDWICH PANEL (PLFP)

In the absence of analytical theory, empirical equation is useful in estimating the ultimate load carrying capacity of structural component. Empirical approach means the collection of data on which to base a theory or derive a conclusion in science. It is part of the scientific method. The empirical method is often contrasts with the precision of the experimental method where data are derived from an experiment. This paper review the development of empirical equation from solid reforced panel to sandwich panel. The previous developed empirical equations are be able to predict an adequate ultimate strength of PLFP panel under axial loading due to the safety factor reduction. Series of experiment and Finite Element ANALYSIS (FEA) were carried out to produce sufficient data to analyze the previous developed empirical equation to predict the ultimate load carrying capacity. From findings, a new empirical equation is in need to predict the ultimate axial load of sandwich panel in order to get accurate prediction.
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The structural behaviour of precast lightweight foamed concrete sandwich panel as a load bearing wall

The structural behaviour of precast lightweight foamed concrete sandwich panel as a load bearing wall

My special thanks and acknowledgement are dedicated to the following individuals who have contributed to the research at various stages. I wish to thank the technical staff of Material and Structural Engineering Laboratory, UTHM, especially Affendi, for his continuous assistance in the experimental work. My appreciation to Koh Heng Boon and my other colleagues for sharing their research experiences and views. I would also like to thank Hafsah Khamis, Norwirdawati and Mohd Faizal for their help during the casting and testing processes.

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Advances in Precast Concrete Sandwich Panels toward Energy Efficient Structural Buildings

Advances in Precast Concrete Sandwich Panels toward Energy Efficient Structural Buildings

Mohamad [10] reported that the compressive strength of the foamed concrete used in producing the panel wythes have a significant effect on the load capacity of the panel and premature crushing and buckling near the supports was observed when slenderness ratio above 18 was used. In addition, Mohamad and Muhammad [28] reported that premature material failure was observed when foamed concrete sandwich panel was tested under eccentric loading. It was inferred that the premature failure and local buckling was because of the lower compressive strength of the foamed concrete below 15 MPa. Also, full-scaled investigation of precast foamed concrete sandwich panel under axial loading with slenderness ratio between 14 to 20 indicated crushing behaviour both at the top and bottom of the panels [29, 30]. This indicates that panels produced using foamed concrete exhibit sudden crushing, unless large cross-section are used. Also, bond slip has been reported between the foamed concrete and the reinforcement due to the low frictional resistance between the two materials. In the other hand, Nooraini [27] reported that foamed concrete with a density range between 300 kg/m3 to 1600 kg/m3 exhibits thermal conductivity between 0.10W/mK to 0.66 W/mK. Also, Jones and McCarthy [31] revealed that the thermal conductivity of foam concrete ranges between 0.23 and 0.42 W/mK at dry densities of 1000 and 1200 kg/m3, respectively. The above mentioned conductivity values are far below conductivity of conventional concrete of 1.88 W/mK. Furthermore, Amran [25] reported that every 100 kg/m3 reduction in density of foamed concrete lead to corresponding increase in thermal insulation by about 0.04 W/mK of the total thermal insulation. However, the reduction in density becomes a disadvantage in terms of structural efficiency. It exhibits high porosity and water absorption behaviour coupled with low compressive strength. The above mentioned criterion are not suitable for load bearing external walls which are subjected to climatic conditions such as rain and snow load, making it highly susceptible to water absorption.
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Precast self compacting concrete (PSCC) panel with added coir fiber: an overview

Precast self compacting concrete (PSCC) panel with added coir fiber: an overview

There also previous research that studied about the composite behaviour of insulated concrete sandwich wall panels (ICSWP) subjected to wind pressure and suction [30]. The specimens was castes full-scaled with different type of insulation and number of glass-fiber-reinforced polymer (GFRP) shear grid. The results show that bonds based on insulation surface roughness were effective under both positive and negative loading test. The calculation of ICWSP’s design strength used the composite behaviour based on surface roughness due to those particular reason.
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Structural Behavior of Precast Prestressed Concrete Sandwich Panels Reinforced with CFRP Grid

Structural Behavior of Precast Prestressed Concrete Sandwich Panels Reinforced with CFRP Grid

To develop the theoretical deflections for fully composite behavior, load deflection curves were calculated for each panel at lateral load intervals of 1 kip up to a lateral load of 60 kips. Throughout the analysis, an applied axial compressive load of 37.8 kips is assumed to be applied on the corbels which simulates the typical testing sequence. The analysis assumes that the moment due to the eccentric location of the applied axial load is resisted by the entire composite section of the panel. Therefore, the eccentricity will be taken from the elastic centroid of the composite section to the location of the applied axial load. Based on the calculated cracked moment of inertia and the gross moment of inertia, the effective moment of inertia at any given loading condition can be evaluated using Branson’s equation as specified in ACI 318-05. It should be noted that the calculation is based on an assumed modulus of rupture of the concrete of 10 f c ' as estimated by Losch (2005) and Mehta et. al. (2006), where f c ′ is the concrete strength on the day of testing.
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Structural behaviour of precast concrete sandwich panel using recycled aggregate concrete under transverse load

Structural behaviour of precast concrete sandwich panel using recycled aggregate concrete under transverse load

Kabir (2005) investigated the structural performance of shotcrete lightweight sandwich panels with compressive strength of 12 MPa and tensile strength of 1.2 MPa under shear and bearing loads. The sandwich panels consisted of shotcrete wythes which enclose the polystyrene core. Three specimens are provided for horizontal bending tests, each sandwich panel is 300 cm long and 100 cm wide with the upper and lower concrete wythes at 6 and 4 cm thick respectively. It was reinforced by the diagonal 3.5 mm cross steel wires welded to the 2.5 mm steel fabric embedded in each wythe as shown in Figure 2.16. Tests for flexural and direct shear loading were carried out based on ASTM E-72 and ASTM 564 respectively.
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Structural behaviour of precast lightweight foamed concrete sandwich panel (PLFP) with double shear truss connectors under eccentric load: preliminary result

Structural behaviour of precast lightweight foamed concrete sandwich panel (PLFP) with double shear truss connectors under eccentric load: preliminary result

PLFP was tested using Magnus Frame with 1000kN loading capacity. Load applied gradually until failure occurred. Figure 2(a) shows the experimental set-up, where the PLFP was clamped to reaction frame correctly in the position to get the targeted end condition. The eccentricity loading was carried out by applying the load at an eccentricity t w /6 along top edge of the panel length during

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Experimental study for structural behaviour of precast lightweight panel (PLP) under flexural load

Experimental study for structural behaviour of precast lightweight panel (PLP) under flexural load

According to the study on the use of additives to enhance properties of preformed foamed concrete [6], it was found that the compressive strength of foam concrete decreased with a reduction of density but the compressive strength increased with the use of additives. This is due to the reduction of water content with the formation of less porous interfacial zone and provided a better interlocking between the paste and the aggregates. The results showed that the mixes with density 1300 and 1600 kg/m 3 are not suitable for structural purposes due to the low compressive strength obtained. The tensile strength and splitting of conventional mixes is higher than mixes with additives. For a given density, the sand content is lower in mixes with additives and degraded the shear capacity.
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Economical and Structural Feasibility of Concrete Cellular and Solid Blocks in Kurdistan Region

Economical and Structural Feasibility of Concrete Cellular and Solid Blocks in Kurdistan Region

The old Iraqi specification standard (ISS) from 1987 gives directions on how to produce the concrete blocks. ISS was created based on American Society for Testing and Materials (ASTM) Specification of materials Part 16 of year 1986, the British Specification (BS) No. 1364 and No. 2028 of year 1968 and Japanese specification A No. 5406 of year 1976. The load-bearing concrete masonry units part of ISS covers resolutions for Dimensions, Categories and Physical requirements in details. The requirements provide instructions for class (A) block as general use in the internal or external walls which are exposed to moisture or climate changes under or above ground level with variation of any dimension must be no more than ± 3 mm. The physical requirements of cellular concrete blocks with an extraction of average value provided for solid and hollow blocks recommended as a minimum compressive strength of 10 N/mm 2 and maximum water absorption of 12.5%, (Siram, 2012). It is also advised that concrete blocks must not be used before 14 days of their production. Factories which failed complying with these ISS recommendations were fined and their product were removed from the market (ISS, 1987). However, since the release of ISS in 1987 Iraq has gone through two wars and ongoing sectarian war therefore follows up regulation has not been a priority for the market in this country.
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Experimental Investigation of Vertical Connections in Precast Wall Panel Under Shear Load

Experimental Investigation of Vertical Connections in Precast Wall Panel Under Shear Load

A continuous vertical bar is provided inside the overlapping loops from the adjacent units. The loops thus couples the adjacent panels. For sufficient out-of-plane support, a panel is adequately connected to the perpendicular panel through overlapping reinforcing loops with the vertical bar. The exterior wall panels along the shorter direction of the building, which constitute the primary shear walls to resist the lateral forces, are provided with six shear keys per storey height. In interior wall joints, reduced number of reinforcement loops are provided per storey height since the shear demand is less.
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Ultimate Strength of Steel Fabric Reinforced Concrete Short Wall Panel Using Crushed Concrete Waste Aggregate (CCwA)

Ultimate Strength of Steel Fabric Reinforced Concrete Short Wall Panel Using Crushed Concrete Waste Aggregate (CCwA)

in term of carrying capacity. The experimental results show that, the wall panel using CCwA show similar structural behaviour in term of ultimate load, displacement profile, and mode of failure. Based on the result, the reinforced concrete wall panel can sustain higher loading without remarkable failure especially when designed with double layer steel fabric, therefore wall panel also can be promoted as a load bearing unit. But for design purposes, the basic design criteria of short wall panel should follow all the parameter in this research such as dimension, grade of concrete, ratio and arrangement of steel fabric, and the range of ultimate load for the infill wall in construction application. When CCwA are accepted in present construction method, the cost and the environmental load in term of concrete waste would decrease compared to the construction without the use of recycled material especially for large-scale construction.
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Study on thermal performance of precast concrete sandwich panel (PCSP) design for sustainable built environment

Study on thermal performance of precast concrete sandwich panel (PCSP) design for sustainable built environment

Gypsum board is an eco-friendly material, which possess a low environment impact and provides good thermal performance. Zhou, Wong, & Lau (2014) [3] had carried out an experimental work which involved a series of heat test on three different design of PCSP. The three specimens include conventional concrete sandwiched layer (C), specimen having a solid gypsum sandwich layer (G) and specimen having a gypsum layer with voids (GV). Table 3.3 shows the temperature of specimens after 12 hours radiation of halogen lamp.

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A Comparative Study on Seismic Analysis and Design of Structural Lightweight and Normal Weight Concrete High Rise Building

A Comparative Study on Seismic Analysis and Design of Structural Lightweight and Normal Weight Concrete High Rise Building

Abstract— Seismic forces acting on the structure mainly depends onto the weight of structure, the primary theme of this work is to reduce the self-weight of the concrete structures, which can be done by using the structural lightweight concrete, it will help in minimizing the lateral seismic forces on the structure and also helps in reducing the size of the structural members and area of reinforcement required while designing. This paper consists of a comparative study on seismic behaviour of G+15 high-rise building made with structural lightweight concrete (SLWC) and normal weight concrete (NWC) for different soil conditions and different zones, by using SLWC at critical conditions results shown that maximum bending moment and shear force got reduced by 40% and 34% respectively and maximum member sizes and steel reinforcement got reduced by 31% and 38% respectively, it has also been found that seismic forces on the structure got reduced considerably.
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