Vol.33/No.1 (129) (2018)
| Title | Long-Term Micro-Vibration Monitoring and Seismic Performance Evaluation of an Existing 10-Story Steel Factory in Hsinchu Science Park |
|---|---|
| Author | Chung-Che Chou, Steven Tsuang, Yu-Ting Ling |
| Keywords | Steel factory, Micro-vibration, Seismic performance, Moment connection |
| Abstract | The Hsinchu Science Park was opening in 1979 and becomes a very important high-tech area in Taiwan to support the economic growth. This work supported by the MOST, Taiwan focused on the micro-vibration and seismic performance of an existing 10-story steel factory that was designed in 1991 and completed in 1995 in Hsinchu Science Park, Taiwan. A few velocity and acceleration meters were used to monitor the building micro-vibration and performance during earthquakes and typhoons. The monitoring duration is from January to October, 2015 while Typhoons Soudelor and Dujuan and several small earthquakes hit the building. The recorded data was used to (1) evaluate the factory performance in terms of micro-vibration in vertical and longitudinal directions, and (2) adjust the building computer model such as the fundamental period and damping ratio. Then, the nonlinear pushover analysis and time history analyses were conducted on the factory model to obtain seismic demands on design-based and maximum-considered earthquake levels. |
| Title | Maximum probable moment strengths of reinforced concrete columns |
|---|---|
| Author | Yu-Chen Ou, Tung-Chun Tsai |
| Keywords | reinforced concrete, columns, maximum probable moment strength, high strength, axial force |
| Abstract | In seismic design, the maximum probable moment strengths of columns need to be calculated for shear design. The maximum probable moment strength is the maximum possible moment strength considering material overstrengths (e.g. actual strengths higher than specified ones, concrete confinement, strain hardening of reinforcement, etc.) and the range of factored axial load acting on the column. Both the codes for design of reinforced concrete structures and seismic design of bridges have include their own provisions to calculate the maximum probable moment strength. Earlier studies have shown that both the code methods tend to show unconservative results with increasing axial compression, particularly for compression-controlled sections. In this research, the ratios of measured moment strength to nominal moment strength of 297 column specimens were examined. The examination confirmed that the ratios increased with increasing axial compression and found that it is mainly due to the effect of concrete confinement. To account for the phenomenon, a general equation for maximum probable moment strength of normal and high-strength columns was developed based on actual material strengths. Comparison with the test data of the 297 columns showed that the proposed equation produced conservative predictions for most of the columns. In contrast, current code equations for reinforced concrete structures and for seismic design of bridges produced unconservative predictions for most of the columns. Moreover, the predictions by the proposed equation showed smaller standard deviation than those by the current code methods. Based on the general equation, two equations were developed based on specified material strengths for normal and high-strength columns. Comparison with the test data of the 297 columns showed the two equations produced results similar to the proposed general equation. |
| Title | Experimental Study of Non-ductile Frame Infilled with RC Shear Wall with Openings |
|---|---|
| Author | Chien-Chuang Tseng, Li-Ping Chen, Shyh-Jiann Hwang |
| Keywords | reinforced concrete, shear wall with openings, window openings, door openings, shear strength, experimental study |
| Abstract | In this study, six specimens of non-ductile RC infilled frames with openings were designed according to the typical low-rise buildings in Taiwan, and these specimens were tested in NCREE. Specimens were categorized into three series, such as single window opening, double window openings and single door opening, and each series has two specimens. Test results indicated that the smaller width of window opening can increase shear strength significantly due to the contribution of wing wall. For the specimens of double window openings, shear strength of vertical wall segments between two window openings is significantly lower as compared with its height-to-length ratio. For the specimens of single door opening, the experimental results showed shear strength only increased slightly by its overhanging wall. In addition, it was indicated that the ductility of the specimen is significantly improved because the larger vertical dimension of door opening can yield higher height-to-length ratio of vertical wall segment. ACI 318-14 building code has equations to predict the shear strength of RC wall with openings. In this paper, ACI 318 building code was used to calculate shear strength and compared with the experimental results to check the applicability of ACI 318-14 code on predicting the shear strength of RC wall with openings applicability. |
| Title | Seismic Design and Tests of the Beam-column Joint in a Buckling-Restrained RC Braced Frame |
|---|---|
| Author | Ting-Li Lin, An-Chien Wu, Kung-Juin Wang, Keh-Chyuan Tsai |
| Keywords | buckling-restrained brace, reinforced concrete structure, corbel, beam-column joint, nonlinear response history analysis |
| Abstract | In this study, the brace connection performance in the new reinforced concrete (RC) frame buildings with buckling-restrained braces (BRBs) arranged in a zigzag configuration is investigated. A 12-story buckling-restrained braced RC building is proposed following the model building codes as a prototype. In order to verify the constructability and the seismic performance of the proposed connection, the beam-column joint at the tenth floor selected as the sub-assemblage specimen was designed and fabricated. The full-scale sub-assemblage, including the BRB gusset bracket and a pair of RC corbels, in the proposed BRB-RCF structural system was tested using cyclic loading procedure. Test results demonstrate that the proposed BRB-to-RC connection details performed very well without failure in the steel gusset bracket or the RC corbels. The design and construction of the sub-assemblage specimen show the feasibility of the proposed system for practical applications. In order to further gain insights into the seismic performance of the BRB-RCF system, nonlinear response history analyses were conducted using a total of 240 (SLE, DBE and MCE) ground accelerations. Analysis results indicate that the mean maximum total BRB shear to base story shear ratios are about 23%, 21% and 19% for SLE, DBE and MCE, respectively. The maximum inter-story drift ratios under the DBE and MCE events are 1.82% and 2.32%, respectively. Analysis results also suggest that the high mode effect is moderate. It is found that the peak demand of the horizontal tension force on the gusset bracket can be estimated by considering 70% of the sum of the horizontal force components computed from the maximum tension strengths of two adjacent BRBs. |
| Title | Development and Analysis of Creep and Shrinkage Database of Concrete in Taiwan |
|---|---|
| Author | Jenn-Chaun Chern, Wen-Cheng Liao, Ting-Kai Liu, Wei-Yi Chin |
| Keywords | Concrete, Creep, Shrinkage, Slag, Fly Ash, Database |
| Abstract | The present study begins with the organization of recent half a century data on the shrinkage and creep testing, and proceeds to refer the parameter formation and data structure in international databases, and combines those with present concrete databases in Taiwan to create the Database on Creep and Shrinkage of Taiwan Concrete. The database incorporates 82 documents, 156 data sets for concrete creep tests, and 303 data sets for concrete shrinkage tests. The material properties, the mix designs, the admixture amounts, the geometry of the test specimens, and the test conditions, for each test, are well documented in this database. Through comparisons with international database analyses and literature reviews, this study has verified that the mix design of concrete in Taiwan, for comparable design strength targets, tends to have the following characteristics: high cement amounts, and low elastic moduli of local aggregate. Finally, this study, in addition to incorporating the Taiwan database into the international concrete databases, is also expected to serve as a base to facilitate the development of the worldwide database with a cloud-based web platform for the world. |