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CONTENTS
Volume 25, Number 5, November 2023
 

Abstract
This study compares two prominent design provisions, National Design Specification (NDS) and Eurocode 5, on load-carrying capacity calculations and failure analysis for mortise-tenon joints. Design procedures of double-shear connection from both provisions were used to calculate load-carrying capacity of mortise-tenon joints with eight different bolt sizes. From this calculation, the result was validated using finite element analysis and failure criteria models. Although both provisions share similar failure modes, their distinct calculation methods significantly influence the design load-carrying capacity values. Notably, Eurocode 5 predicts a 6% higher design load-carrying capacity for mortise-tenon joints with varying bolt diameters under horizontal loads and 14% higher under vertical loads compared to NDS. However, the results from failure criteria models indicate that NDS closely aligns with the actual load-carrying capacity. This indicates that Eurocode 5 presents a less conservative design and potentially requires fewer fasteners in the final timber connection design. This evaluation initiates the potential for the development of a wider range of timber connections, including mortise-tenon joints with wooden pegs.

Key Words
Eurocode 5; load-carrying capacity; mortise-tenon joint; National Design Specification; timber connection

Address
Department of Architecture and Architectural Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea

Abstract
The damping modification factor (DMF) is used to modify the 5%-damped response spectrum to produce spectral values that correspond to other necessary damping ratios for seismic design. The DMF has been the subject of numerous studies, and it has been discovered that seismological parameters like magnitude and distance can have an impact on it. However, DMF formulations incorporating these seismological parameters cannot be directly applied to seismic design because these parameters are not specified in the present seismic codes. The goal of this study is to develop a formulation for the DMF that can be directly applied in seismic design and that takes the effects of magnitude, distance, and site conditions into account. To achieve this goal, 16660 ground motions with magnitudes ranging from 4 to 9 and epicentral distances ranging from 10 to 200 km are used to systematically study the effects of magnitude, distance, and site conditions on the DMF. Furthermore, according to the knowledge that magnitude and distance affect the DMF primarily by changing the spectral shape, a spectral shape factor is adopted to reflect influences of magnitude and distance, and a new formulation for the DMF incorporating the spectral shape factor is developed. In comparison to the current formulations, the proposed formulation provides a more accurate prediction of the DMF and can be employed directly in seismic design.

Key Words
damping modification factor; distance; magnitude; response spectrum; site conditions; spectral shape factor

Address
Haizhong Zhang: Eco-Science Course, Faculty of Agriculture, Yamagata University, 1-23, Wakaba-machi, Tsuruoka-shi, Yamagata 997-8555, Japan
Jia Deng: China Academy of Building Research Co., Ltd, Beijing, 100013, China
Yan-Gang Zhao: Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education, Beijing University of Technology, Beijing, 100124, China

Abstract
The superelastic viscous damper (SVD) is a hybrid passive control device comprising a viscoelastic damper and shape memory alloy (SMA) cables connected in series. The SVD is an innovative damper through which a large amount of seismic energy can dissipate. The current study assessed the seismic collapse induced by steel moment-resisting frames (SMRFs) equipped with SVDs and compared them with the performance of special MRFs and buckling restrained brace frames (BRBFs). For this purpose, nonlinear dynamic and incremental dynamic analysis (IDA) were conducted in OpenSees software. Both 5- and 9-story special MRFs, BRBFs, and MRFs equipped with the SVDs were examined. The results indicated that the annual exceedance rate for maximum residual drifts of 0.2% and 0.5% for the BRBFs and MRFs with SVDs, respectively, were considerably less than for SMRFs with reduced-beam section (RBS) connections and that the seismic performances of these structures were enhanced with the use of the BRB and SVD. The probability of collapse due to residual drift in the SVD, BRB, and RBS frames in the 9-story structure was 1.45, 1.75, and 1.05 times greater than for the 5-story frame.

Key Words
fragility curve; incremental dynamic analysis (IDA); superelastic viscous damper (SVD)

Address
Abbas Ghasemi and Fatemeh Arkavazi: Department of Civil Engineering, Faculty of Civil and Earth Resources Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
Hamzeh Shakib: Department of Civil Engineering, Faculty of Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran

Abstract
High-rise structures are considered as symbols of economic power and leadership. Developing countries like India are also emerging as centers for new high-rise buildings (HRB). As the land is expensive and scarce everywhere, construction of tall buildings becomes the best solution to resolve the problem. But, as building's height increases, its stiffness reduces making it more susceptible to vibrations due to wind and earthquake forces. Several systems are available to control vibrations or deflections; however, outrigger systems are considered to be the most effective systems in improving lateral stiffness and overall stability of HRB. In this paper, a 42-storey RCC HRB is analyzed to determine the optimum position of outriggers of different materials. The linear static analysis of the building is performed with and without the provision of virtual outriggers of reinforced cement concrete (RCC) and pre-stressed concrete (PSC) at different storey levels by response spectrum method using finite element based Extended3D Analysis of building System (ETABS) software for determining responses viz. storey displacement, base shear and storey drift for individual models. The maximum allowable limit and percentage variations in earthquake responses are verified using the guidelines of Indian seismic codes. Results indicate that the outriggers contribute in significantly reducing the storey displacement and storey drift up to 28% and 20% respectively. Also, it is observed that the PSC outriggers are found to be more efficient over RCC outriggers. The optimum location of both types of outriggers is found to be at the mid height of building.

Key Words
base shear; optimum location of outrigger; response spectrum method; storey displacement; storey drift; virtual outrigger system

Address
Department of Civil Engineering, K.E. Society's, Rajarambapu Institute of Technology, Rajaramnagar, Sakharale (Dist. Sangli), MS, India

Abstract
Seismic resilience (SR) plays a vital role in evaluating and improving performance losses along with saving repair costs of structures from potential earthquakes. To further explore the developments, hotspots, and trend directions of SR, a total of 901 articles are obtained from the Web of Science (WoS) database. CiteSpace software is used to conduct a bibliometric analysis, which indicates an upward trend of publications in SR and explores the relationship of countries, journals, cited references, and keywords based on visual maps and detailed tables. Then, based on the results of the bibliometric analysis, a state-of-the-art review is conducted to further explore the current challenges and trend directions of SR. The trend directions can be divided into five categories: (a) SR assessments of infrastructure structures, (b) multi-hazard quantifications of SR, (c) seismic resilient structures, (d) refining and calibrating analytical models, and (e) multi-criteria decision-making frameworks for sustainability and SR.

Key Words
assessment framework; bibliometric analysis; functionality; seismic resilience; state-of-the-art review

Address
School of Civil Engineering, Guangzhou University, Guangzhou 510006, China

Abstract
The parameters of the multiple-vertical-line-element model (MVLEM) of reinforced concrete (RC) shear walls are often empirically determined, which causes large simulation errors. To improve the simulation accuracy of the MVLEM for RC shear walls, this paper proposed a novel method to determine the MVLEM parameters using the artificial neural network (ANN). First, a comprehensive database containing 193 shear wall specimens with complete parameter information was established. And the shear walls were simulated using the classic MVLEM. The average simulation errors of the lateral force and drift of the peak and ultimate points on the skeleton curves were approximately 18%. Second, the MVLEM parameters were manually optimized to minimize the simulation error and the optimal MVLEM parameters were used as the label data of the training of the ANN. Then, the trained ANN was used to generate the MVLEM parameters of the collected shear walls. The results show that the simulation error of the predicted MVLEM was reduced to less than 13% from the original 18%. Particularly, the responses generated by the predicted MVLEM are more identical to the experimental results for the testing set, which contains both flexure-control and shear-control shear wall specimens. It indicates that establishing MVLEM for RC shear walls using ANN is feasible and promising, and that the predicted MVLEM substantially improves the simulation accuracy.

Key Words
artificial neural network; multiple-vertical-line-element model; numerical simulation; shear wall

Address
Xiaolei Han, Lei Zhang and Jing Ji: 1) State Key Laboratory of Subtropical Building and Urban Science, South China University of Technology, Guangzhou 510641, China, 2) School of Civil Engineering & Transportation, South China University of Technology, Guangzhou 510641, China
Yankun Qiu: School of Civil Engineering & Transportation, South China University of Technology, Guangzhou 510641, China

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