Browsing by Author "Herrera, Ricardo"

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    Numerical Study on Cyclic Response of End-Plate Biaxial Moment Connection in Box Columns
    (2020) Gallegos, Marco; Nunez, Eduardo; Herrera, Ricardo
    The 2008 Wenchuan-China earthquake showed the importance of considering the bidirectional seismic action as a cause of failure in column hinge mechanisms. Subsequently, the large 2011 Tohoku-Japan earthquake revealed that Special Moment Frames buildings, made of tubular columns (Hollow Structural Section or Built-up Box Section) and rigid connections with I-beams, did not suffer serious damage. However, only the ConXtech((R)) ConXL (TM) moment connection has been prequalified according to the (American Institute of Construction) AISC Seismic Provisions for use with tubular columns and the rest of connections do not consider biaxial resistance. The research reported herein investigated the cyclic response of box-columns joints, connected to I beams using the four-bolt extended endplate connection, subjected to bidirectional bending and axial load on the column. To conduct the study, complex nonlinear finite element models (FEMs) of several I beam to box column joint configurations were constructed and analyzed under cyclic loading using the ANSYS software. The results reveal that the failure is concentrated in the beams of all joint configurations except for the columns with axial load equal to 75% of the column capacity, where a combined failure mechanism is achieved. The energy dissipation capacity of joints with a greater number of beams is lower than joints with fewer beams. The bidirectional effect of the seismic action and the level of axial load must be considered to avoid the formation of a column-hinge fragile failure mechanism also the behavior exhibited by 3D joints is more realistic than 2D joints according to real structures.
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    Reconnaissance Report of Chilean Industrial Facilities Affected by the 2010 Chile Offshore Bio-Bio Earthquake
    (EARTHQUAKE ENGINEERING RESEARCH INST, 2012) Zareian, Farzin; Aguirre, Carlos; Felipe Beltran, Juan; Cruz, Ernesto; Herrera, Ricardo; Leon, Roberto; Millan, Arturo; Verdugo, Alejandro
    This paper summarizes findings of an EERI reconnaissance team and a group of Chilean experts on damage to industrial facilities caused by the 27 February 2010 Offshore Bio-Bio Earthquake and ensuing tsunami. Chile's industry as a whole was severely affected when major industrial plants such as paper mills, wood mills, thermoelectric power plants, and oil and gas refineries were shut down following the earthquake either in response to the damage sustained or to maintain structural and environmental safety. Damage resulted primarily from ground shaking; however, it was exacerbated by the ensuing tsunami in coastal areas. Important industrial sectors, such as the wine industry and fishing, pulp and paper industries, suffered severely. Observed damage was primarily due to inadequate anchorage of equipment, differential movements between adjacent supports of piping and equipment, foundation displacements, and failure of nonstructural elements and equipment. [DOI: 10.1193/1.4000049]