EXPANDED POLYSTYRENE FIBRED LIGHTWEIGHT CONCRETE (EPSF-LWC) AS A LOAD BEARING WALL PANEL

2015 ◽  
Vol 76 (9) ◽  
Author(s):  
Jamilah Abd Rahim ◽  
Siti Hawa Hamzah ◽  
Hamidah Mohd Saman
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Steel Fibre ◽  
Lightweight Concrete ◽  
Expanded Polystyrene ◽  
Mix Design ◽  
Wall Panel ◽  
Element Analysis ◽  
Load Bearing ◽  
Mix Proportion

This study was conducted to determine the optimum mix proportion of lightweight concrete (LWC) containing expanded polystyrene (EPS) and steel fiber which is designated as Expanded Polystyrene Fibred Lightweight Concrete (EPSF-LWC) for load bearing wall application. In order to produce LWC, EPS beads were chosen as lightweight aggregate because it gives advantages in term of energy absorbing capacity which suitable for structure that would be exposed to impact like shear wall. However, EPS beads possess zero strength. Therefore, steel fibre was added to improve LWC strength and also to reduce occurrence of micro and macro crack. In the mix design method, the percentage of EPS beads adding to the mix are differ while the percentage of steel fibre is same. The result showed optimum mix design was the one that contained 30% of EPS and 0.5 % of steel fibre and is designated as M8. The compressive strength EPSF-LWC of mix proportion designated as M8 is 19.51 MPa with density 1939 kg/m3. It is greater than 17 MPa as the requirement for structure component application that stated in the BS8110. Hence, reinforced and unreinforced EPS-LWC wall panels were constructed to determine the maximum loading that wall can sustain and deflection profile EPSF-LWC wall panel for the loaded to failure. The wall was set up under pinned-fixed end support condition. The sample was modelled using finite element analysis (FEA) for validation with experimental programme.  The maximum loading capacity was found to be 908.20 kN and 853.40 kN for each reinforced (WR5) and unreinforced (WUR5) of EPSF-LWC wall panel. These loading were 31% to 35% less than finite element analysis. However, WR5 and WUR5 EPSF-LWC wall panel was deformed in single curvature profile for both experimental and FEA. Maximum deflection for WR5and WUR5 of EPSF-LWC recorded is 10.27 mm and 12.95 mm occurred at 0.7 heights (H) of wall panel. According to Euler buckling load theory, the location of maximum lateral displacement of wall panel sample is influenced by the type of fixity at end support of the sample.

BUCKLING OF STEEL FIBRE EXPANDED POLYSTYRENE CONCRETE WALL PANEL

2015 ◽  
Vol 76 (10) ◽  
Author(s):  
Rohana Mamat ◽  
Siti Hawa Hamzah ◽  
Jamilah Abd. Rahim
Keyword(s):  
Steel Fibre ◽  
Lightweight Concrete ◽  
Slenderness Ratio ◽  
Expanded Polystyrene ◽  
Sustained Load ◽  
Wall Panel ◽  
Concrete Wall ◽  
Maximum Displacement ◽  
Load Bearing ◽  
Wall Panels

Steel Fibre Expanded Polystyrene Concrete (SFEPS) wall panel is envisaged as load bearing walls, although it is lightweight by design. The performance of this wall is investigated, incorporating opening to fulfil the demand for ventilation and services conduits or equipments. It focused on the buckling behaviour by comparing the carrying load capacities and deformation profiles of wall panel with and without opening. Primarily, the samples were cast from concrete mixed with expanded polystyrene (EPS) beads, enhanced with hooked end round shaft steel fibre and reinforced with a single layer rectangular steel fabric (BRC) of size B9. The wall panel size is 2000 mm in height (limited due to testing frame allowable height), 1500 mm wide and 100 mm thick which gives the slenderness ratio of 15. The wall falls under the slender wall category for lightweight concrete since the slenderness ratio is greater than 10 [1]. A central opening with a size of 600 mm high by 600 mm wide is created to accommodate the opening criterion. Experimental tests were conducted simulating fixed ends condition. The average compressive strength of SFEPS, fcu is 20.87 N/mm2 with a density, ρ of 1900 kg/m3. These lightweight SFEPS wall panels sustained load between 958.0 kN and 1938.9 kN. Wall panels experienced maximum displacement of 22.3 mm at midheight. The wall panels failed in buckling as it should be for slender wall. There was also concrete crushing at the upper and lower ends of the panels. The SFEPS wall panel is suitable to be used as load bearing structures.

Finite Element Analysis Applied in Structural Integrity Management

2014 ◽  
Author(s):  
Jacob Dybwad ◽  
Mads Bryndum ◽  
Russell Hollingworth
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Crack Growth ◽  
Crack Development ◽  
Mitigation Measures ◽  
Element Analysis ◽  
Load Bearing ◽  
Design Elements ◽  
Non Linear ◽  
Anchor Block

During the periodic inspection of the Alvheim subsea system 2013 a number of cracks were observed at the Mid Water Arch (MWA) tether anchoring arrangement. The MWA and associated anchor block are critical design elements. Detailed investigations were initiated in order to determine future development of the cracks and their severity. The application of advanced non-linear finite element analysis as part of the inspection and maintenance strategy resulted in significant cost savings compared to a solution based on immediate mitigation action. This paper describes the background for occurrence of these cracks and the analyses used to determine their development: • The cracks are located in non-loadbearing locking brackets. The function of the brackets is primarily to secure the pins connecting the top part of the tether hinge to the anchor block. • During construction the locking brackets were welded to the pin and to the tether hinge. This way the non-structural element became part of the load bearing system resulting in very high stresses in the bracket and subsequent crack development. It could not immediately be excluded that the cracks observed could initiate further cracking into main bearing parts of the hinge. • FE modeling using Abaqus [1] was used to analyze the criticality of the situation. Non-linear material properties and removal of elements were applied in order to simulate crack initiation and crack growth. The system was analyzed by modelling the load paths from initial assembly on land, installation loads and finally the loads during operation. Removal of elements was introduced to replicate the crack growth pattern observed on ROV still photos from periodic surveys 2012 and 2013. The analysis documented the principle mechanism behind the crack development and further demonstrated that the risk of failure of any of the load bearing elements was negligible. The results of the analysis provided the necessary documentation for the appropriate precautions and at the same time plan for execution of mitigation measures which would have minimal economic impact.

Finite Element Analysis of the Pull-Out Specimens of Steel Reinforced Lightweight Concrete

2012 ◽  
Vol 166-169 ◽  
pp. 514-519
Author(s):  
Jian Wen Zhang ◽  
Shi Hui Guo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Lightweight Concrete ◽  
Constitutive Relationship ◽  
Test Results ◽  
Concrete Element ◽  
Element Analysis ◽  
Bond Slip ◽  
Spring Element ◽  
Pull Out

Finite element analysis method of steel reinforced lightweight concrete pull-out specimens is exploded based on the test results. Spring element and local bond slip constitutive relation are introduced in analysis so as to consider the interfacial bond-slip between steel and lightweight concrete. Element tributary area and flange or web position should be taken into account in order to confirm the spring element real constant. Analysis results indicate that specimens bearing capacity and deformation can be well simulated adopting the stated method and constitutive relationship.

Finite-Element Modeling and Analysis of Early-Age Cracking Risk of Cast-In-Place Concrete Culverts

2018 ◽  
Vol 2672 (27) ◽  
pp. 24-36 ◽  
Author(s):  
Yalin Liu ◽  
Anton K. Schindler ◽  
James S. Davidson
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Expansion ◽  
Lightweight Concrete ◽  
Coefficient Of Thermal Expansion ◽  
Early Age ◽  
Thermal Coefficient ◽  
Element Analysis ◽  
Joint Spacing ◽  
Cracking Risk

Extensive cracking was found in several cast-in-place concrete culverts in Alabama. This condition can decrease the long-term durability of the culverts. Early-age stress development in concrete is influenced by temperature changes, modulus of elasticity, stress relaxation, shrinkage, thermal coefficient of expansion, and the degree of restraint. The objective of this study is to determine means to mitigate early-age cracking in culverts by evaluating the cracking risk. Finite-element analysis was used to model the early-age stress by accounting for the following factors: construction sequencing, support restraint, concrete constituents, temperature effects, and the time-dependent development of mechanical properties, creep/relaxation, and drying shrinkage. Experimental results from restraint to volume change tests with rigid cracking frames were used to verify the accuracy of the finite-element analysis. A parametric study was performed to quantify the effect of changing joint spacing, joint type, construction sequence, concrete coefficient of thermal expansion, placement season, and concrete type on the risk of early-age cracking. The finite-element model results revealed that the use of the following measures will reduce the risk of early-age cracking in cast-in-place concrete culverts: concrete with lower coefficient of thermal expansion, contraction joints, sand-lightweight concrete or all-lightweight concrete, and scheduling the casting of the culvert wall to minimize the difference in its placement time relative to its previously cast base. Alternatively, to minimize the contribution of thermal effects on risk of cracking, the construction schedule should be developed to avoid concrete placement during hot weather conditions.

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