National Center for Researcher on Earthquake Engineering

Taipei, Taiwan

National Center for Researcher on Earthquake Engineering

Taipei, Taiwan
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Sung Y.-C.,National Taipei University of Technology | Sung Y.-C.,National Center for Researcher on Earthquake Engineering | Wang C.-Y.,National Center for Researcher on Earthquake Engineering
Journal of the Chinese Institute of Civil and Hydraulic Engineering | Year: 2015

With the advantages of easy coding and effortless mathematic-compiling, genetic algorithm (GA) is a popular optimization solver of artificial intelligence. However, converging to the local optimum may be a general problem of it. In order to overcome this drawback, a hybrid optimization algorithm integrating local model of particle swarm optimization (PSO) and conventional GA to speed up efficiency as well as increase accuracy for global optimization was proposed to deal with optimum post-tensioning cable force in design of the cable-stayed bridges. Two case studies were performed and discussed. The results obtained shows the proposed method has a better performance than conventional GA and could benefit the engineers in optimual design of the cable-stayed bridges. ©, 2015, Chinese Institute of Civil and Hydraulic Engineering. All right reserved.


Liu K.-Y.,National Center for Researcher on Earthquake Engineering | Wang P.-H.,National Center for Researcher on Earthquake Engineering | Lee Z.-K.,National Center for Researcher on Earthquake Engineering | Lee L.-S.,National Center for Researcher on Earthquake Engineering | And 3 more authors.
Journal of the Chinese Institute of Civil and Hydraulic Engineering | Year: 2013

This paper presented a series of in-situ seismic performance tests of a bridge before its demolition due to accumulated souring-induced problem. The experiment programs included three cyclical loading tests and one pseudo-dynamic test. Built in 1995, the tested three single piers was 1.8 in diameter with longitudinal ratio of 0.95% and lateral reinforce ratio of 0.294%. The aspect ratio ranges from 5.3 to 5.7. P3 column represents a benchmark specimen with exposed length of 1.2 m, while P4 was exposed up to 4 m. P2 was subjected to code-compatible ground acceleration and then followed by a one-cycle pushover test. Based on the test results, the bridge behaved mostly elastic under 0.32 g excitation. The ultimate lateral strength obtained could satisfy design target of plastic hinge moment, and the maximum drift ratio reached 5%. However, insufficient design of lateral reinforcement without seismic hook resulted in buckling of longitudinal reinforcements and loose of lateral reinforcements. Besides, it was due to gravel material and retrofitted caisson which provided large lateral resistance, even exposed 1/3 of the caisson length, the seismic performance among three piers had minor difference, and had been compared by the proposed analytical model in OpenSees with good accuracy. The experience learnt was hoped to beneficial the planning of in-situ test of a piled bridge with scouring issue, and to verify the seismic performance of bridges with similar conditions.


Sung Y.-C.,National Taipei University of Technology | Chang K.-C.,National Taiwan University | Chen C.-H.,National Taiwan University | Ueng T.-S.,National Taiwan University | And 5 more authors.
Journal of the Chinese Institute of Civil and Hydraulic Engineering | Year: 2014

This etcpaper intends to study the interaction of dynamic response between bridge pile and soil surrounding through shaking table test of sandbox. The experimental dynamic responses of the bridge pier with pile located at dry and saturated sand, respectively, were obtained through the experiment model including mass block, bridge column and pile embed in sandbox conducted by National Center of Research on Earthquake Engineering (NCREE). The experimental results were served as the database for investigation. In additional to a deeper discussions on the differences between experimental results of dry sand and saturated sand, this paper used software of OpenSees to establish a three dimensional finite element model for nonlinear time history analysis. Through comparing the analytical results and experimental results, the accuracy of the model established was able to be assured so that the soil structure interaction between pile and soil (dry sand/saturated sand) can be better understood and served as prediction for the similar cases in practical engineering application. ©, 2014, Chinese Institute of Civil and Hydraulic Engineering. All right reserved.


Liu K.-Y.,National Center for Researcher on Earthquake Engineering | Chang K.-C.,National Taiwan University | Sung Y.-C.,National Taipei University of Technology | Lin G.-J.,National Taipei University of Technology | Chen J.-W.,National Taipei University of Technology
Journal of the Chinese Institute of Civil and Hydraulic Engineering | Year: 2013

This study presents the experimental study on the seismic performance of bridge column with high strength concrete and reinforcements, called New RC column. Given a specified plastic moment strength resulted from a predetermined RC column with ordinary materials, the design objective of New RC column is to provide same plastic moment strength but reducing the cross section, quantities of longitudinal and lateral reinforcement simultaneously. Total of one RC and five New RC square columns were carried out by cyclical loading tests. For New RC specimens, the design compressive strength of concrete, yielding strength of longitudinal and lateral reinforcement are 68.7, 686.7, and 784.8 MPa, respectively, while RC column are 27.5, 412.0, and 274.7 MPa. Experimental results demonstrated that New RC column can reduce cross section up to 30%, eliminate 25% number of longitudinal bars, and 20% of the lateral reinforcement without changing its flexural-dominate failure mode. In addition, the pushover curve can be well predicted by the proposed program. It is because of enhanced shear capacity and low axial load ratio that New RC is superior to RC bridge column and its application can be expected in the future.


Liu K.-Y.,National Center for Researcher on Earthquake Engineering | Sung Y.-C.,National Taiwan University | Chang K.-C.,National Taipei University of Technology | Chiu C.-K.,National Taiwan University of Science and Technology | And 2 more authors.
Journal of the Chinese Institute of Civil and Hydraulic Engineering | Year: 2014

This study presents the experimental study on the seismic performance of bridge column with high strength concrete and reinforcements, called New RC column. The design objective of New RC multicolumn bent is to provide same plastic moment as convention RC bridge but reducing the cross section, quantities of both longitudinal and lateral reinforcements simultaneously. Specimens RCF and NEWRCF were 4 m in center-to-center span length and 4 m in clear height. The detected compressive strength of concrete, yielding strength of longitudinal and lateral reinforcement was 80, 723, and 833 MPa for NEWRCF, respectively, while RCF were 42, 521, and 335 MPa. Experimental results demonstrated both RCF and NEWRCF satisfied the design target of moment strength, and regulations of displacement ductility in Seismic Design Specification of Highway Bridge. In addition, the pushover curves obtained by the proposed program were agreed with experimental results. Experimental results were recommended to revise the requirements of material properties of steel and lower bound of the structural ductility for multicolumn bent system. ©, 2014, Chinese Institute of Civil and Hydraulic Engineering. All right reserved.


Yeh F.-Y.,National Center for Researcher on Earthquake Engineering | Chang K.-C.,National Taiwan University | Liao W.-C.,National Taiwan University | Lien W.-Y.,National Taiwan University
Journal of the Chinese Institute of Civil and Hydraulic Engineering | Year: 2014

Structural monitoring system is important in civil engineering. There are some advantages in carbon fiber reinforced concrete, such as high tensile strength, high ductility which increase seismic capacity and security of structures. The traditional structural monitoring system has some disadvantage such as the life of sensor is shorter than structures. To find a sensor with long life as structure, in this research we used CFRC (Carbon Fiber Reinforced Concrete) as the structural monitoring sensor. CFRC with the functionality similar to piezoresistivity material can be used as a self-sensing material for strain measurement and damage detection. It is based on the reversible effect of strain on the volume electrical resistivity and the irreversible effect of damage on the resistivity. The strain sensing behavior is such that the resistivity decreases reversibly upon compression due to the slight push-in of crack-bridging fibers and the consequent decrease of the contact electrical resistivity of the fiber-cement interface. Similarly, the resistivity increases reversibly upon tension due to the slight pull-out of crack-bridging fibers and the consequent decrease of the contact resistivity.

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