Vol.30/No.2 (118) (2015)
| Title | Study on Structural Analysis of Cantilever Erection Process for Cable-Stayed Bridges |
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| Author | Yu-Chi Sung, Chun-Ying Wang, Eng-Hwa Teo |
| Keywords | Artificial intelligence, Optimization analysis, Construction stage analysis |
| Abstract | Cantilever erection method is popularly used in construction of long span cable-stayed bridges. The structural configuration, boundary condition and construction loading are changed sequentially during erection process. In order to make the eventual structural performance at final erection stage consistent to the design of complete bridge, structural analysis of erection process is indeed important. This study used hybrid GA to develop an automatic analysis for cantilever erection process of the cable-stayed bridges. The case study was performed and the analytical results were discussed. The results obtained show the method developed can deal with the optimum construction planning of cable-stayed bridges using cantilever erection. |
| Title | Quality Assessments on T-Shape Electro-Slag Welds (ESWs) of Internal Diaphragm to Box-Column Plate |
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| Author | Ker-Chun Lin, Sheng-Jhih Jhuang, Chao-Hsien Li, Chih-Han Lin |
| Keywords | steel box column, electro-slag welds (ESW), diaphragm, ultrasonic testing (UT), heat affected zone (HAZ), Charpy V-notch (CVN) toughness, hardness |
| Abstract | The welding procedure of electro-slag welds (ESW) is one of the most efficient welding methods for a T-shape joint of internal diaphragm to column plate of steel box column. Therefore, it is widely used to steel building structures in order to save making time of steel structure fabrication shop in Taiwan. Unfortunately, according to the past research results on beam-to-column connection with the box column, there was at least 25% fractured probability of ESWs joints, join internal diaphragm to column plate of the box column, to occur unacceptably premature brittle-fracture before its beam end’s plastic hinge not developing. Based on observation of macro metallurgical photos from the past studies, local inadequate melting due to welds bias is one of the most important factors to result in this failure mode. To prevent the ESW from fracture in the beam-to-column connection, this research focused on mechanical characteristics of ESW and near parts, fabrication procedure of the existing ESW in Taiwan and ultrasonic testing (UT) technology. The research results indicated that the ESW joint between internal diaphragm and column plate of the box column due to its high heat-input caused heat affected zone (HAZ) on base metal of the column plate brittle under its slow heat-dissipation from the column plate. In addition, the existing ESW technology can’t be effectively controlled and obtain stable quality of welds. However, the UT is a feasible and most economic nondestructive method to inspect the ESW welds. This research proposed an integral UT inspection technology include inspecting sensors, procedure and acceptable criteria. A fabricated detail also was advised in this paper to prevent the ESW from local inadequate melting. The proposed technologies of fabrication and inspection can not only effectively ensure the ESW quality but also significantly increase seismic performance of the steel beam-to-box column connections. |
| Title | Investigation on the Differences between the Property of Shear Plastic Hinge of RC Beam and Column Members Determined by SERCB and NCREE Software |
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| Author | Chin-Sheng Kao, Yu-Chun Sun, Jim Chang |
| Keywords | Beam and Column Members, Shear, Property of Plastic Hinge, Seismic Capability |
| Abstract | Since the 921 Chi-chi earthquake, domestic technicians have used SERCB and NCREE software to actively assess and reinforce the seismic capacity of low-rise school structures for over ten years, and have accumulated a significant amount of experience. Now as domestic people have already fully understood these two sets of software and after the differences between the property of moment plastic hinge of RC beam and column members determined by these two sets of software have been investigated in the previous paper[1], this paper continues investigate the differences between the property of shear plastic hinge of RC beam and column members determined by these two sets of software as well as their impact on the assessment results of the seismic capacity of RC buildings structure in order to confirm whether there are areas of improvement for these two sets of software. |
| Title | A nonlinear static analysis study of a RC structure with walls |
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| Author | Hsin-Hung Chen, I-Chau Tsai |
| Keywords | RC wall, equivalent column, lateral load-lateral displacement response, nonlinear static analysis |
| Abstract | Knowing a lateral load-lateral displacement response of an RC wall is an important work of executing nonlinear static analysis and evaluating earthquake-resistant capacity of an RC structure with RC walls. This paper explains how to calculate the moment-bending displacement response of an RC wall under axial load and moment properly, and calculate the shear-shear displacement response of the RC wall under axial load and shear by using the modified compression-field theory (MCFT) with considering the effect of the height-depth ratio (Hin/Lw). By integrating the moment-bending displacement response and the shear-shear displacement response, the lateral load-lateral displacement response of the RC wall under axial load-moment-shear interaction can be decided reasonably. In addition, to provide an application illustration for engineers, this paper establishes a 6 floor RC structure with walls and a 6 floor RC structure with walls containing windows to explain how to use an equivalent column model to simulate an RC wall on SAP2000 or ETABS nonlinear static analysis. |
| Title | The study of the seismic assessment parameters of a new design building by nonlinear static pushover analysis |
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| Author | Te-Kuang Chow, Yeong-Kae Yeh |
| Keywords | new design, seismic design specification, seismic evaluation, nonlinear pushover analysis |
| Abstract | At present, the commonly used method for new building design is based on the current seismic design specification,according to seismic requirements and the allowable toughness capacity,which provides designers with minimum total horizontal force design level, and then combined with the response spectrum to complete the elastic design, before those structure members reach the nonlinear stage. The current seismic assessment procedures using the nonlinear pushover analysisgain the result .The result of performance target ground acceleration is used to compare with the site peak ground acceleration of design earthquake with a 475-year return period to evaluate the seismic capacity is enough or not.This article explores the parameters of their differences between the latest seismic design specifications in accordance with the building design and the use of seismic evaluation of pushover analysis.Using the Civil 404-100 as the new design case, run the nonlinear pushover analysis to gain the performance target ground acceleration.Whether initial yield lateral force or capacity curve, are higher than the current seismic design specifications. It illustrates that the current seismic design specifications has the more conservative minimum design lateral force and the toughness capacity. |