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Papers by Ta-heng Wang
ACI Journal Proceedings, 1954
The natural frequency of axial-loaded concrete beam decreases with increasing applied compressive... more The natural frequency of axial-loaded concrete beam decreases with increasing applied compressive force, and the natural frequency of tensioned cable increases with increasing tensile force. However, the variation of natural frequency of prestressed concrete beam (PCB) consisting of concrete and cable has rarely been discussed based on both |the rigorous mathematic model and experimental results. In this study, a testing program was conducted and Rayleigh's method was used to derive an approximate equation for computing natural frequency. The results indicate that (1) the natural frequency decreases with increasing prestressing force for PCB with eccentric parabolic tendon, but it is no change for PCB with eccentric straight tendon, (2) the proposed equation was proved to be an adequate method for estimating first mode natural frequency in vertical direction, and (3) a modified computed method for effective moment of inertia of PCB was also proposed.
The natural frequency of axial-loaded concrete beam decreases with increasing applied compressive... more The natural frequency of axial-loaded concrete beam decreases with increasing applied compressive force, and the natural frequency of tensioned cable increases with increasing tensile force. However, the variation of natural frequency of prestressed concrete beam (PCB) consisting of concrete and cable has rarely been discussed based on both |the rigorous mathematic model and experimental results. In this study, a testing program was conducted and Rayleigh's method was used to derive an approximate equation for computing natural frequency. The results indicate that (1) the natural frequency decreases with increasing prestressing force for PCB with eccentric parabolic tendon, but it is no change for PCB with eccentric straight tendon, (2) the proposed equation was proved to be an adequate method for estimating first mode natural frequency in vertical direction, and (3) a modified computed method for effective moment of inertia of PCB was also proposed.
For post-tension prestressed concrete beams, both of tendons laid in metal duct and wrapped by pl... more For post-tension prestressed concrete beams, both of tendons laid in metal duct and wrapped by plastic sheets are recognized as unbonded tendon by researchers, and the same equation is used to estimate the flexural strength. But the contacting conditions between tendon and its surrounding concrete are quite different for these two kinds of unbonded tendons. This study compares the flexural strength, crack distribution and crack width of beams with these two kinds of unbonded tendons and bonded tendon. The results reveal that the structural behavior of tendon wrapped by plastic sheets is between bonded tendon and tendon laid in metal duct. A modified equation is proposed to estimate flexural strength of tendon wrapped by plastic sheets. Reducing cost and shortening construction time are the main advantages for this kind of the prestressed beams with tendon wrapped by plastic sheets. After further investigation, it may be an alternative method for the post-tension prestressed concrete structure in the future.
ACI Journal Proceedings, 1954
The natural frequency of axial-loaded concrete beam decreases with increasing applied compressive... more The natural frequency of axial-loaded concrete beam decreases with increasing applied compressive force, and the natural frequency of tensioned cable increases with increasing tensile force. However, the variation of natural frequency of prestressed concrete beam (PCB) consisting of concrete and cable has rarely been discussed based on both |the rigorous mathematic model and experimental results. In this study, a testing program was conducted and Rayleigh's method was used to derive an approximate equation for computing natural frequency. The results indicate that (1) the natural frequency decreases with increasing prestressing force for PCB with eccentric parabolic tendon, but it is no change for PCB with eccentric straight tendon, (2) the proposed equation was proved to be an adequate method for estimating first mode natural frequency in vertical direction, and (3) a modified computed method for effective moment of inertia of PCB was also proposed.
The natural frequency of axial-loaded concrete beam decreases with increasing applied compressive... more The natural frequency of axial-loaded concrete beam decreases with increasing applied compressive force, and the natural frequency of tensioned cable increases with increasing tensile force. However, the variation of natural frequency of prestressed concrete beam (PCB) consisting of concrete and cable has rarely been discussed based on both |the rigorous mathematic model and experimental results. In this study, a testing program was conducted and Rayleigh's method was used to derive an approximate equation for computing natural frequency. The results indicate that (1) the natural frequency decreases with increasing prestressing force for PCB with eccentric parabolic tendon, but it is no change for PCB with eccentric straight tendon, (2) the proposed equation was proved to be an adequate method for estimating first mode natural frequency in vertical direction, and (3) a modified computed method for effective moment of inertia of PCB was also proposed.
For post-tension prestressed concrete beams, both of tendons laid in metal duct and wrapped by pl... more For post-tension prestressed concrete beams, both of tendons laid in metal duct and wrapped by plastic sheets are recognized as unbonded tendon by researchers, and the same equation is used to estimate the flexural strength. But the contacting conditions between tendon and its surrounding concrete are quite different for these two kinds of unbonded tendons. This study compares the flexural strength, crack distribution and crack width of beams with these two kinds of unbonded tendons and bonded tendon. The results reveal that the structural behavior of tendon wrapped by plastic sheets is between bonded tendon and tendon laid in metal duct. A modified equation is proposed to estimate flexural strength of tendon wrapped by plastic sheets. Reducing cost and shortening construction time are the main advantages for this kind of the prestressed beams with tendon wrapped by plastic sheets. After further investigation, it may be an alternative method for the post-tension prestressed concrete structure in the future.