Seismic behaviour of concrete wall bridge pier reinforced with Shape Memory Alloy

Reinforced concrete bridge (RC) was designed with high ductility and built-in high seismic areas to prevent collapse from a seismic event. During Hashin-Hawaii seismic event in 1995, it was observed that bridge wall pier performance in a weak direction is still far from the acceptable level. The bridge wall pier suffered from high residual drift making the bridge unserviceable. The performance-based seismic design (PBSD) is a comprehensive method that limits the local and global deformation of the bridge to the acceptable design load level. The objective of PBSD can be accomplished by implementing Shape Memory Alloy (SMA) as a reinforcement bar to enhance seismic performance in concrete bridge piers. This research aims to investigate the seismic behavior in weak directions for wall bridge pier reinforced with shape memory alloy. To provide comprehensive information, this study started with a parametric study to evaluate the influence of geometry and material properties using fractional factorial analysis. The test results were explored to evaluate the influence of concrete strength, steel yield strength, SMA yield strength, longitudinal and transverse reinforcement ratio, aspect ratio, and skew angle. In addition, the aspect ratio result was calibrated with experimental work. The seismic performance of a 1/3 scaled wall pier reinforced with SMA was investigated experimentally using lateral cyclic loading in the weak direction. In addition, the test result was compared to the conventional reinforced concrete wall in terms of hysteretic curves, maximum and residual drift, displacement recovery capacity, and energy dissipation. The quantitative damage states associated with different performance levels (cracking, yielding, spalling, and crushing) for RC wall pier reinforced with three different types of SMAs were developed using Incremental Dynamic Analysis (IDA). Based on an extensive numerical study using IDA, the effect of compressive strength, aspect ratio, and longitudinal and transverse reinforcement ratio was evaluated for three different types of SMAs. Finally, vulnerability curves are established for three different RC-SMA wall piers using maximum and residual drift as engineering demand parameters. It was discovered that the RC- SMA wall pier has a low probability of damage and minimizes residual drift, which significantly contributes to the life cycle cost benefit.Applied Science, Faculty ofEngineering, School of (Okanagan)Graduat

Analytical Seismic Fragility Curves for Reinforced Concrete Wall pier using Shape Memory Alloys considering maximum drift

Fragility curves express the seismic vulnerability of bridge piers for different damage states at various earthquake intensities. A fragility curve typically gives a physical understanding of repair costs and functionally levels of a bridge pier. Shape memory alloys (SMAs) provide a promising alternative material in reducing the failure probability of a bridge pier. This study develops a family of seismic fragility curves for reinforced concrete (RC) wall piers reinforced with three different types of SMA rebar in plastic hinge regions. An incremental dynamic analysis (IDA) using a total of 20 earthquake ground motions was performed on a SMA-RC wall pier to evaluate its seismic performance. The maximum drift recorded for each ground motion was taken as the seismic performance demand parameter of interest in this study. The probabilistic seismic demand model (PSDM) was used to generate fragility curves for each RC-SMA wall pier. The results show that the different mechanical properties and type of SMAs affect the performance of RC-SMA wall pier

Evacuation egress in high rise building: Review of the current design evacuation solution

In the aftermath of the September 11th attack, design of tall buildings particularly in the aspect of safety systems and structural robustness, arguably the most crucial issues that is deliberated till to date. Concerning the safety systems specifically on evacuation egress, many novels and innovative evacuation solutions for high rise buildings that have been researched and put forward, for instances Platform Rescue Systems (PRS), Controlled Descent Devices (CDD) and Escape Chutes. Still, the practicability of the existing proposed egress systems to be implemented in the real-life situation and its compliance with the tall building design legislation remain unknown. For developing countries such as Malaysia and United Arab Emirates, tall buildings play a role as an iconic landmark. While countries like China and Hong Kong, tall building is needed due to the scarcity of land and high populations. As more than one hundred tall structure exists in the world, and will be increasing by 2020; therefore, it is urgently needed that existing engineering practices in designing tall building to be reviewed with respect to evacuation egress. The main objective of this paper is to create awareness among developers, consultants and contractors that proper evacuation egress in tall building design and development is a must. This paper provides a comprehensive review of the existing engineering practices on tall building evacuation planning systems and design. Furthermore, the effectiveness of the currently proposed systems and its consideration amongst structural and safety engineers are also reported

Evacuation egress in high rise building: Review of the current design evacuation solution

In the aftermath of the September 11th attack, design of tall buildings particularly in the aspect of safety systems and structural robustness, arguably the most crucial issues that is deliberated till to date. Concerning the safety systems specifically on evacuation egress, many novels and innovative evacuation solutions for high rise buildings that have been researched and put forward, for instances Platform Rescue Systems (PRS), Controlled Descent Devices (CDD) and Escape Chutes. Still, the practicability of the existing proposed egress systems to be implemented in the real-life situation and its compliance with the tall building design legislation remain unknown. For developing countries such as Malaysia and United Arab Emirates, tall buildings play a role as an iconic landmark. While countries like China and Hong Kong, tall building is needed due to the scarcity of land and high populations. As more than one hundred tall structure exists in the world, and will be increasing by 2020; therefore, it is urgently needed that existing engineering practices in designing tall building to be reviewed with respect to evacuation egress. The main objective of this paper is to create awareness among developers, consultants and contractors that proper evacuation egress in tall building design and development is a must. This paper provides a comprehensive review of the existing engineering practices on tall building evacuation planning systems and design. Furthermore, the effectiveness of the currently proposed systems and its consideration amongst structural and safety engineers are also reported