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Ipoh, Malaysia

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. Source


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. Source


Nematollahi B.,University Putra Malaysia | Voo Y.L.,DURA Technology Sdn Bhd | Saifulnaz M. R. R.,University Putra Malaysia
KSCE Journal of Civil Engineering | Year: 2014

One of the main breakthroughs in the concrete technology in the 20th century was the development of Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) as a new generation of sustainable construction material. This paper is presented in two parts. The analysis and design procedures as well as the Environmental Impact Calculations (EIC) of the precast UHPFRC cantilever retaining walls as a sustainable alternative approach to conventional precast Reinforced Concrete (RC) cantilever retaining walls were presented in the first part (Part I) of this paper. In this part (Part II), the reliability of the precast UHPFRC cantilever retaining walls were evaluated through full scale experimental testing. In the experimental tests, four full-scale UHPFRC wall specimens with the dimensions of 2.5 m in height, 2 m in length, and 2 m in width were cast. The area of the steel bars used in the wall stem of the specimens, and the volumetric ratio of the steel fibers used in the UHPFRC mix design were the test parameters. The experimental results proved that the precast cantilever retaining walls manufactured from UHPFRC as a sustainable alternative solution has superior properties in all aspects compared to the conventional precast RC cantilever retaining wall. © 2014 Korean Society of Civil Engineers and Springer-Verlag Berlin Heidelberg. Source


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. Source


Nematollahi B.,University Putra Malaysia | Raizal Saifulnaz M.R.,University Putra Malaysia | Voo Y.L.,DURA Technology Sdn Bhd
Research Journal of Applied Sciences, Engineering and Technology | Year: 2014

This study evaluates the environmental impacts of a newly designed precast Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) cantilever retaining wall as a sustainable alternative approach compared with the conventional precast Reinforced Concrete (RC) cantilever retaining wall. Nowadays, according to the shocking reports of many researchers worldwide global warming is one of the most devastating problems of human being. To date, lots of research has been undertaken in the concrete industry to tackle this issue through reducing the environmental footprints of our structural designs. In this regard, UHPFRC technology offers substantial benefits through efficient use of materials as well as optimization of the structural designs resulting less CO2 emissions, Embodied Energy (EE) and Global Warming Potential (GWP). UHPFRC as a sustainable construction material is mostly appropriate for the use in the fabrication of precast members such as precast concrete cantilever retaining walls. This study demonstrates the overview of the designed precast concrete cantilever retaining wall manufactured from UHPFRC and its Environmental Impact Calculations (EIC) versus the conventional precast RC cantilever retaining walls. Based on the EIC results, the precast UHPFRC cantilever retaining walls are generally more environmentally sustainable than those built of the conventional RC with respect to the reduction of CO2 emissions, EE and GWP. In summary, the precast UHPFRC cantilever retaining wall proposed in this study is an alternative sustainable solution compared with the conventional precast RC cantilever retaining wall which can be used in many civil engineering projects. © Maxwell Scientific Organization, 2014. Source

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