50 research outputs found

    Countdown to Martial Law: The U.S-Philippine Relationship, 1969-1972

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    Between 1969 and 1972, the Philippines experienced significant political unrest after Philippine President Ferdinand Marcos’ successful reelection campaign. Around the same time, American President Richard Nixon formulated a foreign policy approach that expected its allies to be responsible for their own self-defense. This would be known as the Nixon Doctrine. This approach resulted in Marcos’ declaration of martial law in September 1972, which American officials silently supported. American officials during this time also noted Marcos’ serving of American business and military interests. Existing literature differed on the extent Marcos served what he thought were American interests. Stanley Karnow’s In Our Image noted that Marcos did not adequately serve American interests, noting that he sent an insignificant amount of soldiers to Vietnam. Karnow also did not mention business interests. Raymond Bonner’s Waltzing with a Dictator mentioned that Marcos was effective for serving American business and military interests. James Hamilton-Paterson’s America’s Boy agrees with Bonner’s assessment, also noting that Marcos served American business and military interests. Materials from the Digital National Security Archive (DNSA) and Foreign Relations of the United States (FRUS) series affirmed Bonner and Hamilton-Paterson’s position, while noting that Karnow’s work was outdated because of the limited information he had when In Our Image was published. There are three issues that concerned the U.S.-Philippine relationship under President Marcos during this time. The first issue was the societal and political unrest that threatened to undermine Marcos. The second issue concerned U.S. officials’ application of the Nixon Doctrine to the Philippines. The third regarded President Marcos’ serving of military and business interests in the Philippines. Marcos supported maintaining America’s Filipino bases, which were important hubs of American military operations during the Vietnam War. In addition to military interests, President Marcos also aided American businesses in the Philippines, by removing restrictions that threatened American business activity. Each of these concerns led to President Marcos’ declaration of martial law. American officials’ tacit support for Marcos reflected their commitment to the Nixon Doctrine, which ensured political stability that preserved American business and military interests

    Evaluation of the flexural strength and serviceability of geopolymer concrete beams reinforced with glass-fibre-reinforced polymer (GFRP) bars

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    Geopolymer concrete reinforced with glass-fibre-reinforced polymer (GFRP) bars can provide a construction system with high durability, high sustainability, and adequate strength. Few studies deal with the combined use of these materials, and this has been the key motivation of this undertaking. In this study, the flexural strength and serviceability performance of the geopolymer concrete beams reinforced with GFRP bars were evaluated under a four-point static bending test. The parameters investigated were nominal bar diameter, reinforcement ratio, and anchorage system. Based on the experimental results, the bar diameter had no significant effect on the flexural performance of the beams. Generally, the serviceability performance of a beam is enhanced when the reinforcement ratio increases. The mechanical interlock and friction forces provided by the sand coating was adequate to secure an effective bond between the GFRP bars and the geopolymer concrete. Generally, the ACI 4401.R-06 and CSA S806-12 prediction equations underestimate the beam strength. The bending-moment capacity of the tested beams was higher than that of FRP-reinforced concrete beams from the previous studies

    Behaviour of concentrically loaded geopolymer-concrete circular columns reinforced longitudinally and transversely with GFRP bars

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    The behavior of concentrically loaded geopolymer-concrete circular columns reinforced longitudinally and transversely with glass–fiber-reinforced-polymer (GFRP) bars was investigated. Six full-scale short columns (L/r = 8) were cast: one column without transverse reinforcement; three columns with circular hoops spaced at 50 mm, 100 mm, and 200 mm on centers; and two columns with spirals spaced at 50 mm and 100 mm on centers. In addition, two slender columns (L/r = 16) transversely reinforced with hoops and spirals both spaced at 100 mm on centers were fabricated. Based on the experimental results, the GFRP bars contributed an average of 7.6% to the overall capacity of the tested columns. The hoop- and spiral-confined slender columns failed at a load equal to 66% and 82%, respectively, of the strength of their counterpart short columns. Irrespective of the tie configuration, the columns with higher volumetric ratios showed better compressive behavior than those with lower volumetric ratios. The ductility and confinement efficiency of the spiral-confined columns were higher than that of their counterpart hoop-confined columns. The tested columns yielded relatively superior compression performance compared to OPC-based concrete columns reinforced with GFRP bars and ties. Further studies dealing with the behavior and slenderness limit in GFRP-reinforced geopolymer concrete slender columns are recommended to increase its uptake in the construction industry

    Flexural performance of concrete beams reinforced with steel–FRP composite bars

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    YesFlexural performance of concrete beams reinforced with steel–FRP composite bar (SFCB) was investigated in this paper. Eight concrete beams reinforced with different bar types, namely one specimen reinforced with steel bars, one with fiber-reinforced polymer (FRP) bars and four with SFCBs, while the last two with hybrid FRP/steel bars, were tested to failure. Test results showed that SFCB/hybrid reinforced specimens exhibited improved stiffness, reduced crack width and larger bending capacity compared with FRP-reinforced specimen. According to compatibility of strains, materials’ constitutive relationships and equilibrium of forces, two balanced situations, three different failure modes and balanced reinforcement ratios as well as analytical technique for predicting the whole loading process are developed. Simplified formulas for effective moment of inertia and crack width are also proposed. The predicted results are closely correlated with the test results, confirming the validity of the proposed formulas for practical use.National Natural Science Foundation of China (51678514), China Postdoctoral Science Foundation (2018M642335), the Science and Technology Project of Jiangsu Construction System (2018ZD047), the Cooperative Education Project of Ministry of Education, China (201901273053), the Blue Project Youth Academic Leader of Colleges and Universities in Jiangsu Province (2020), the Six Talent Peaks Project of Jiangsu Province (JZ038, 2016) and the Yangzhou University Top Talents Support Projec

    GLUE-LAMINATED COMPOSITE SANDWICH BEAMS FOR STRUCTURAL ENGINEERING AND CONSTRUCTION

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    The Thirteenth East Asia-Pacific Conference on Structural Engineering and Construction (EASEC-13), September 11-13, 2013, Sapporo, Japan

    Countdown to martial law: The U.S.-Philippine relationship, 1969-1972

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    Between 1969 and 1972, the Philippines experienced significant political unrest after Philippine President Ferdinand Marcos’ successful reelection campaign. Around the same time, American President Richard Nixon formulated a foreign policy approach that expected its allies to be responsible for their own self-defense. This would be known as the Nixon Doctrine. This approach resulted in Marcos’ declaration of martial law in September 1972, which American officials silently supported. American officials during this time also noted Marcos’ serving of American business and military interests. Existing literature differed on the extent Marcos served what he thought were American interests. Stanley Karnow’s In Our Image noted that Marcos did not adequately serve American interests, noting that he sent an insignificant amount of soldiers to Vietnam. Karnow also did not mention business interests. Raymond Bonner’s Waltzing with a Dictator mentioned that Marcos was effective for serving American business and military interests. James Hamilton-Paterson’s America’s Boy agrees with Bonner’s assessment, also noting that Marcos served American business and military interests. Materials from the Digital National Security Archive (DNSA) and Foreign Relations of the United States (FRUS) series affirmed Bonner and Hamilton-Paterson’s position, while noting that Karnow’s work was outdated because of the limited information he had when In Our Image was published. There are three issues that concerned the U.S.-Philippine relationship under President Marcos during this time. The first issue was the societal and political unrest that threatened to undermine Marcos. The second issue concerned U.S. officials’ application of the Nixon Doctrine to the Philippines. The third regarded President Marcos’ serving of military and business interests in the Philippines. Marcos supported maintaining America’s Filipino bases, which were important hubs of American military operations during the Vietnam War. In addition to military interests, President Marcos also aided American businesses in the Philippines, by removing restrictions that threatened American business activity. Each of these concerns led to President Marcos’ declaration of martial law. American officials’ tacit support for Marcos reflected their commitment to the Nixon Doctrine, which ensured political stability that preserved American business and military interests

    Flexural behaviour of glass fibre reinforced polymer (GFRP) bars subjected to elevated temperature

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    The FRP reinforced concrete structures may be exposed to high temperatures that may reduce the structural integrity of the bars, and eventually of the entire structure. Therefore, the thermal stability of the FRP bars must be thoroughly investigated before they can be fully utilized in the construction industry. The flexural strength testing has long been a staple technique for measuring the uniaxial tensile strength of the brittle materials because it is inexpensive and convenient to run rather than the direct tension test. Although the results obtained were not the absolute tensile data, they can provide an indication about the relative tensile performance of the FRP bars. In this study, the flexural behaviour of the GFRP bars of varying nominal diameters (12.7 mm, 14.0 mm, 15.9 mm, 17.0 mm, and 20.5 mm) subjected to elevated temperatures (up to 150 °C) was investigated. The results showed that as the temperature increases, the flexural strength and stiffness of the GFRP bars decreases. As the temperature approaches the glass transition temperature (Tg) of the bars, a drastic strength and stiffness reduction was observed. These findings were also observed in the pure tension testing of the FRP bars done by other researchers. The bars with a larger nominal diameter showed a better flexural strength decay resistance than those with a smaller nominal diameter at elevated temperatures. However, a comparable flexural stiffness deterioration was observed at an increasing temperature

    Investigation on the mechanical behavior of hybrid fibre reinforced polymer composite beam

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    Fibre reinforced polymer (FRP) composites have been proven a viable alternative to conventional construction materials such as timber, steel, and reinforced concrete due to its high strength-to-weight, light weight, durable, and corrosion resistant properties. Several studies suggested the effective use of FRP composites in sandwich structures. This paper presents the physical and mechanical properties of a sandwich-structured glue-laminated beam, named as hybrid FRP composite beam, developed by CarbonLOC Pty Ltd in cooperation with the Centre of Excellence in Engineered Fibre Composites (CEEFC) in University of Southern Queensland (USQ). This beam combines the strength and stiffness of glue-laminated panels oriented in the edgewise position bonded with the high tensile strength and modulus Glass Fibre Reinforced Polymer (GFRP) skin plates at the top and bottom. The average experimental failure loads of the beam in flexure, shear, longitudinal compression, and tangential compression are 53.45 kN, 211.73 kN, 450.06 kN, and 220.31 kN, respectively, which corresponds to strength of 106.90 MPa, 35.29 MPa, 75.01 MPa, and 61.20 MPa, respectively. The effective stiffness of the beam was enhanced due to top and bottom GFRP plates. Theoretical prediction showed reasonably comparable failure load with the experimental results
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