Current Issue : April - June Volume : 2014 Issue Number : 2 Articles : 6 Articles
The seismic design of most civil structures is usually accomplished using the response spectrum approach or\r\nsimplified equivalent lateral force methods. However, some special tasks require the use of dynamic time history\r\nanalyses. In the nuclear industry, for example, dynamic analyses are required in the design verification and seismic\r\nassessment of critical buildings and in the development of floor response spectra and free-field ground response\r\nspectra. The input motion for these analyses requires acceleration time series whose response spectrum matches a\r\ntarget design spectrum. This article revises the continuous wavelet transform (CWT) approach to generate\r\nspectrum-compatible records from the modification of acceleration time histories recorded in actual seismic events.\r\nThe computational efficiency of the algorithm is increased greatly by performing the wavelet decomposition and\r\ndetails reconstruction via fast convolution using fast Fourier transforms. The new algorithm is evaluated using a\r\ntypical design spectrum from the nuclear industry and different seed records....
The purpose of this study was to investigate the design comparison of totally prefabricated bridge substructure system.\r\nPrefabricated bridge substructure systems are a relatively new and versatile alternative in substructure design that can offer\r\nnumerous benefits. The system can reduce the work load at a construction site and can result in shorter construction periods. The\r\nprefabricated bridge substructures are designed by the methods of Korea Highway Bridge Code (KHBD) and load and resistance\r\nfactor design (AASHTO-LRFD). For the design, the KHBD with DB-24 and DL-24 live loads is used. This study evaluates the\r\ndesign method of KHBD (2005) and AASHTO-LRFD (2007) for totally prefabricated bridge substructure systems. The computer\r\nprogram, reinforced concrete analysis in higher evaluation system technology was used for the analysis of reinforced concrete\r\nstructures. A bonded tendon element is used based on the finite element method, and can represent the interaction between the\r\ntendon and concrete of a prestressed concrete member. A joint element is used in order to predict the inelastic behaviors of\r\nsegmental joints. This study documents the design comparison of totally prefabricated bridge substructure and presents conclusions\r\nand design recommendations based on the analytical findings....
After reviewing the background and motivations for using modern computational methods for the design of reinforced\r\nconcrete structures, an algorithm making use of the object oriented programming language Python and professionally developed\r\nfinite element software is presented for the sizing and placement of the reinforcement in RC structures. The developed method is\r\nthen used to design the reinforcement of a deep beam. To validate the design, two identical deep beam specimens were manufactured\r\nwith the obtained steel, and then tested in the laboratory. It was found that the experimental results corroborated those\r\npredicted with the finite element design method....
Bridge monitoring system via information technology is capable of providing more accurate knowledge of bridge\r\nperformance characteristics than traditional strategies. This paper describes not only an integrated Internet\r\nmonitoring system that consists of a stand-alone monitoring system (SMS) and a Web-based Internet monitoring\r\nsystem (IMS) for bridge maintenance but also its application to para-stressing bridge system as an intelligent structure.\r\nIMS, as a Web-based system, is capable of addressing the remote monitoring by introducing measuring information\r\nderived from SMS into the system through Internet or intranet connected by either PHS or LAN. Moreover, the key\r\nfunctions of IMS such as data management system, condition assessment, and decision making with the proposed\r\nsystem are also introduced in this paper. Another goal of this study is to establish the framework of a para-stressing\r\nbridge system which is an intelligent bridge by integrating the bridge monitoring information into the system to\r\ncontrol the bridge performance automatically....
This study evaluates the shear strength of steel fiber reinforced concrete (SFRC) beams from a database, which consists\r\nof extensive experimental results of 222 SFRC beams having no stirrups. In order to predict the analytical shear strength of the\r\nSFRC beams more precisely, the selected beams were sorted into six different groups based on their ultimate concrete strength\r\n(low strength with f 0\r\nc\\50 MPa and high strength with f 0\r\nc\\50 MPa), span-depth ratio (shallow beam with a/d C 2.5 and deep\r\nbeam with a/d\\2.5) and steel fiber shape (plain, crimped and hooked). Principal component and multiple regression analyses\r\nwere performed to determine the most feasible model in predicting the shear strength of SFRC beams. A variety of statistical\r\nanalyses were conducted, and compared with those of the existing equations in estimating the shear strength of SFRC beams. The\r\nresults showed that the recommended empirical equations were best suited to assess the shear strength of SFRC beams more\r\naccurately as compared to those obtained by the previously developed models....
Prestressed concrete cylindrical pipe (PCCP) has been widely used for the distribution of water in communal,\r\nindustrial, and agricultural systems for a long time. However, as it deteriorates, structural failures have been experienced.\r\nReplacing the entire existing PCCP with partial damages is not an economical method. Currently, as a cost effective repairing\r\nmethod, a new approach using fiber reinforced polymer (FRP) has been applied. A new design procedure of this method was\r\nproposed considering various kinds of loading condition. However, it is not easy to apply this method for design purpose due to its\r\ncomplex procedures. The objective of this study is to provide a new design criteria and process for PCCP rehabilitation with FRP.\r\nThrough this method, the appropriate quantities of FRP layers will be decided after examining of limit states of deteriorated PCCP.\r\nFor this purpose, two deterioration conditions are assumed; fully deteriorated and partially deteriorated. Different limit states for\r\neach case are applied to decide the quantities of attached FRP. The concept of ââ?¬Ë?ââ?¬Ë?margin of safetyââ?¬â?¢Ã¢â?¬â?¢ is used to judge whether the\r\ndesign results are within the optimal ranges to satisfy all limit states....
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