DURA Technology Sdn Bhd

Ipoh, Malaysia

DURA Technology Sdn Bhd

Ipoh, Malaysia
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Voo Y.L.,Dura Technology Sdn Bhd | Augustin P.C.,Dura Technology Sdn Bhd
Structural Engineer | Year: 2011

A single span 50m long prestressed road bridge has been fabricated under a Public Works Department contract in the State of Negeri Sembilan, Malaysia. The bridge, across a river, was constructed at the small village of Kampung Linsum, Sungai Linggi. To date, this bridge is the first in Malaysia and may also be the world's longest composite road bridge made from ultra-high performance ductile concrete (UHPdC). This paper presents the features of the UHPdC precast girder; gives a brief insight into the manufacturing process of the girder; highlights the bridge's construction sequence; illustrates the design method and provides an environmental impact calculation. The midspan deflections of the bridge at different times in its construction history were compared against the collected field data and these figures showed that the calculated values were in general in agreement with the field data. © Yen Lei Voo, Patrick C. Augustin & Thomas A. J. Thamboe.


Panjehpour M.,University Putra Malaysia | Ali A.A.A.,University Putra Malaysia | Anwar M.P.,University of Nottingham Malaysia Campus | Aznieta F.N.,University Putra Malaysia | Voo Y.L.,DURA Technology Sdn Bhd
International Journal of Engineering Research in Africa | Year: 2012

B-Regions are parts of the structure in which Bernoulli's principle of straight-line strain is used. D-Regions are parts of the structure with a complicated variation in strain. In essence, D-Regions contain the parts of structure which are near to the concentrated forces or steep changes in geometry which are so-called geometrical discontinuities or static discontinuities. Strut-and-Tie Model (STM) is one of the best models to analyse the D-regions. Nevertheless, according to the existing literature, there are still some challenges about STM which are addressed in this paper. STM and its details are investigated to show its common challenges presents some recommendations to overcome these challenges. According to this review, the major challenges in STM are related to the strut effectiveness factor, static uncertainties of STM, strain compatibility, and anchorage requirements in STM. The scope of this research is confined to the two dimensional STM. © (2012) Trans Tech Publications, Switzerland.


Lei Voo Y.,Dura Technology Sdn. Bhd | Foster S.J.,University of New South Wales
IES Journal Part A: Civil and Structural Engineering | Year: 2010

This article presents an overview of the material characteristics of a Malaysia blend of ultra-high performance 'ductile' concrete (UHPdC). Examples of the environmental impact calculations of UHPdC structures compared to that of conventional reinforced concrete (RC) design are presented. The comparison studies show that many structures constructed from UHPdC are generally more environmentally sustainable than built of the conventional RC with respect to the reduction of CO2 emissions, embodied energy and global warming potential. The enhanced durability of UHPdC also provides for significant improvements in the design life, further supporting the concept of sustainable development. © 2010 The Institution of Engineers, Singapore.


Tayeh B.A.,Universiti Sains Malaysia | Tayeh B.A.,Islamic University of Gaza | Abu Bakar B.H.,Universiti Sains Malaysia | Megat Johari M.A.,Universiti Sains Malaysia | Voo Y.L.,Dura Technology Sdn. Bhd.
Construction and Building Materials | Year: 2012

As a rule of thumb, the interfacial bonding between deteriorated concrete structures with a newly overlay repair material is one of the most important factors for structural functionality and safety as well as durability performance. In order to acquire an enhanced resistance against penetration of harmful substances, a good and effective bonding is necessary at the concrete interfaces. The objective of this study is to examine experimentally the mechanical properties and permeability characteristics of the interface between normal concrete (NC) substrate which represents old concrete structures and an overlay of ultra high performance fiber concrete (UHPFC) as a repair material. The mechanical interfacial bond characteristics were assessed using the slant shear and splitting tensile tests to quantify the influence of the differently roughened substrate surfaces. On the other hand, the permeability characteristics were evaluated by means of the rapid chloride permeability, gas and water permeability tests. The results show that the newly overlay UHPFC achieves high bond strength and bonds efficiently with the NC substrates. The specimens with sand blasted substrate surface give the best interfacial mechanical bonding in comparison to other types of surface preparation. The permeability tests proved that the interfacial bonding is very good and efficient which significantly improve the impermeability of the composites, and this was clearly shown by the SEM micrograph of the interface. Hence, it is envisaged that the use of UHPFC concomitant with appropriate surface preparation of the substrate should be able to provide effective and durable concrete repair. © 2012 Elsevier Ltd. All rights reserved.


Tayeh B.A.,Universiti Sains Malaysia | Abu Bakar B.H.,Islamic University of Gaza | Megat Johari M.A.,Islamic University of Gaza | Voo Y.L.,Dura Technology Sdn. Bhd
Procedia Engineering | Year: 2013

Under normal circumstances, reinforced concrete structures (RCS) show excellent performance in terms of durability and structural behaviour except for the zones that are subjected to severe mechanical or cyclic loading and aggressive environmental conditions. Therefore the methods of rehabilitation or strengthening of these zones should be reliable, effective and economical. Today, many scientists, academics and engineers understood the extremely low porosity and low permeability characteristics of ultra high performance fibre concrete (UHPFC) giving its enhanced durability over high performance concrete (HPC), thus making it potentially suitable for rehabilitation and retrofitting problematic RCS. The advantages of utilising the technology of UHPFC in repairing works includes (i) decrease the working time needed for the rehabilitation works; and (ii) increase the serviceability and durability to an extent where the repaired structures can meet the expected design life of the structures, with minor preventative measure. This paper discusses and reviewing some of the most recent issues and findings using UHPFC as a repair material. The results of the findings will also be presented to prove that the UHPFC displays excellent repair and retrofit potentials in compressive and flexure strengthening and possesses high bonding strength and bond durability as compared with other types concrete. © 2013 The Authors.


Panjehpour M.,INTI International University | Chai H.K.,University of Malaya | Voo Y.L.,DURA Technology SDN Bhd
PLoS ONE | Year: 2015

Deep beams are commonly used in tall buildings, offshore structures, and foundations. According to many codes and standards, strut-and-tie model (STM) is recommended as a rational approach for deep beam analyses. This research focuses on the STM recommended by ACI 318-11 and AASHTO LRFD and uses experimental results to modify the strut effectiveness factor in STM for reinforced concrete (RC) deep beams. This study aims to refine STM through the strut effectiveness factor and increase result accuracy. Six RC deep beams with different shear span to effective-depth ratios (a/d) of 0.75, 1.00, 1.25, 1.50, 1.75, and 2.00 were experimentally tested under a four-point bending set-up. The ultimate shear strength of deep beams obtained from non-linear finite element modeling and STM recommended by ACI 318-11 as well as AASHTO LRFD (2012) were compared with the experimental results. An empirical equation was proposed to modify the principal tensile strain value in the bottle-shaped strut of deep beams. The equation of the strut effectiveness factor from AASHTTO LRFD was then modified through the aforementioned empirical equation. An investigation on the failure mode and crack propagation in RC deep beams subjected to load was also conducted. © 2015 Panjehpour et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Panjehpour M.,University Putra Malaysia | Ali A.A.A.,University Putra Malaysia | Voo Y.L.,DURA Technology Sdn Bhd | Aznieta F.N.,University Putra Malaysia
Computers and Concrete | Year: 2014

Strut-and-tie model (STM) has been recommended by many codes and standards as a rational model for discontinuity regions in structural members. STM has been adopted in ACI building code for analysis of reinforced concrete (RC) deep beams since 2002. However, STM recommended by ACI 318-11 is only applicable for analysis of ordinary RC deep beams. This paper aims to develop the STM for CFRP strengthened RC deep beams through the strut effectiveness factor recommended by ACI 318-11. Two sets of RC deep beams were cast and tested in this research. Each set consisted of six simply-supported specimens loaded in four-point bending. The first set had no CFRP strengthening while the second was strengthened by means of CFRP sheets using two-side wet lay-up system. Each set consisted of six RC deep beams with shear span to effective depth ratio of 0.75, 1.00, 1.25, 1.50, 1.75, and 2.00. The value of strut effectiveness factor recommended by ACI 318-11 is modified using a proposed empirical relationship in this research. The empirical relationship is established based on shear span to effective depth ratio. Copyright © 2014 Techno-Press, Ltd.


Panjehpour M.,University of Malaya | Chai H.K.,University of Malaya | Voo Y.L.,DURA Technology Sdn Bhd
Scientific World Journal | Year: 2014

Strut-and-tie model (STM) method evolved as one of the most useful designs for shear critical structures and discontinuity regions (D-regions). It provides widespread applications in the design of deep beams as recommended by many codes. The estimation of bottle-shaped strut dimensions, as a main constituent of STM, is essential in design calculations. The application of carbon fibre reinforced polymer (CFRP) as lightweight material with high tensile strength for strengthening D-regions is currently on the increase. However, the CFRP-strengthening of deep beam complicates the dimensions estimation of bottle-shaped strut. Therefore, this research aimed to investigate the effect of CFRP-strengthening on the deformation of RC strut in the design of deep beams. Two groups of specimens comprising six unstrengthened and six CFRP-strengthened RC deep beams with the shear span to the effective depth ratios (a/d) of 0.75, 1.00, 1.25, 1.50, 1.75, and 2.00 were constructed in this research. These beams were tested under four-point bending configuration. The deformation of struts was experimentally evaluated using the values of strain along and perpendicular to the strut centreline. The evaluation was made by the comparisons between unstrengthened and CFRP-strengthened struts regarding the widening and shortening. The key variables were a/d ratio and applied load level. © 2014 Mohammad Panjehpour et al.


Voo Y.L.,DURA Technology Sdn Bhd | Poon W.K.,DURA Technology Sdn Bhd | Foster S.J.,University of New South Wales
Journal of Structural Engineering | Year: 2010

While the database of tests on shear in reinforced concrete members without stirrups is extensive, the pool of test data for fiber-reinforced specimens is limited. Fewer still are tests undertaken on high-performance fiber-reinforced concrete members with the fiber concrete designed to carry the full shear capacity. This paper reports the results of a testing program on ultrahigh-performance steel fiber-reinforced concrete beams. Eight prestressed concrete beams were tested in shear with the test variables being the shear span-to-depth ratio and the quantity and type of steel fibers. The results of the tests, together with additional tests reported in the literature, are compared to the values derived from the plastic shear variable engagement predictive model for the determination of shear strength of steel fiber-reinforced concrete beams. A good correlation is observed with a mean model to experimental strength ratio of 0.92 and coefficient of variation of 0.12. © 2010 ASCE.


PubMed | DURA Technology Sdn Bhd, INTI International University and University of Malaya
Type: Journal Article | Journal: PloS one | Year: 2015

Deep beams are commonly used in tall buildings, offshore structures, and foundations. According to many codes and standards, strut-and-tie model (STM) is recommended as a rational approach for deep beam analyses. This research focuses on the STM recommended by ACI 318-11 and AASHTO LRFD and uses experimental results to modify the strut effectiveness factor in STM for reinforced concrete (RC) deep beams. This study aims to refine STM through the strut effectiveness factor and increase result accuracy. Six RC deep beams with different shear span to effective-depth ratios (a/d) of 0.75, 1.00, 1.25, 1.50, 1.75, and 2.00 were experimentally tested under a four-point bending set-up. The ultimate shear strength of deep beams obtained from non-linear finite element modeling and STM recommended by ACI 318-11 as well as AASHTO LRFD (2012) were compared with the experimental results. An empirical equation was proposed to modify the principal tensile strain value in the bottle-shaped strut of deep beams. The equation of the strut effectiveness factor from AASHTTO LRFD was then modified through the aforementioned empirical equation. An investigation on the failure mode and crack propagation in RC deep beams subjected to load was also conducted.

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