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| 1 | Development of a new connection for precast concrete walls subjected to cyclic loading显示文摘The Industrialized Building System(IBS) was recently introduced to minimize the time and cost of project construction.Accordingly, ensuring the integration of the connection of precast components in IBS structures is an important factor that ensures stability of buildings subjected to dynamic loads from earthquakes, vehicles, and machineries.However, structural engineers still lack knowledge on the proper connection and detailed joints of IBS structure construction.Therefore, this study proposes a special precast concrete wall-to-wall connection system for dynamic loads that resists multidirectional imposed loads and reduces vibration effects(PI2014701723).This system is designed to connect two adjacent precast wall panels by using two steel U-shaped channels(i.e., male and female joints).During casting, each joint is adapted for incorporation into a respective wall panel after considering the following conditions: one side of the steel channel opens into the thickness face of the panel; a U-shaped rubber is implemented between the two channels to dissipate the vibration effect; and bolts and nuts are used to create an extension between the two U-shaped male and female steel channels.The developed finite element model of the precast wall is subjected to cyclic loads to evaluate the performance of the proposed connection during an imposed dynamic load.Connection performance is then compared with conventional connections based on the energy dissipation, stress, deformation, and concrete damage in the plastic range.The proposed precast connection is capable of exceeding the energy absorption of precast walls subjected to dynamic load, thereby improving its resistance behavior in all principal directions. | Ramin Vaghei Farzad Hejazi Hafez Taheri Mohd Saleh Jaafar Farah Nora Aznieta Abdul Aziz | 2017 | Earthquake Engineering and Engineering Vibration2017，16，1： | 8 |
| 2 | Structural behavior of axially loaded precast foamed concrete sandwich panels显示文摘 | Y.H. Mugahed Amran A.A. Abang Ali Raizal S.M. Rashid Farzad Hejazi Nor Azizi Safiee | 2016 | Construction and Building Materials2016，，： | 1 |
| 3 | Development of hybrid optimization algorithm for structures furnished with seismic damper devices using the particle swarm optimization method and gravitational search algorithm显示文摘Previous studies about optimizing earthquake structural energy dissipation systems indicated that most existing techniques employ merely one or a few parameters as design variables in the optimization process,and thereby are only applicable only to simple,single,or multiple degree-of-freedom structures.The current approaches to optimization procedures take a specific damper with its properties and observe the effect of applying time history data to the building;however,there are many different dampers and isolators that can be used.Furthermore,there is a lack of studies regarding the optimum location for various viscous and wall dampers.The main aim of this study is hybridization of the particle swarm optimization(PSO) and gravitational search algorithm(GSA) to optimize the performance of earthquake energy dissipation systems(i.e.,damper devices) simultaneously with optimizing the characteristics of the structure.Four types of structural dampers device are considered in this study:(ⅰ) variable stiffness bracing(VSB) system,(ⅱ) rubber wall damper(RWD),(ⅲ) nonlinear conical spring bracing(NCSB) device,(iv) and multi-action stiffener(MAS) device.Since many parameters may affect the design of seismic resistant structures,this study proposes a hybrid of PSO and GSA to develop a hybrid,multi-objective optimization method to resolve the aforementioned problems.The characteristics of the above-mentioned damper devices as well as the section size for structural beams and columns are considered as variables for development of the PSO-GSA optimization algorithm to minimize structural seismic response in terms of nodal displacement(in three directions) as well as plastic hinge formation in structural members simultaneously with the weight of the structure.After that,the optimization algorithm is implemented to identify the best position of the damper device in the structural frame to have the maximum effect and minimize the seismic structure response.To examine the performance of the proposed PSO-GSA optimization method,it has been applied to a three-story reinforced structure equipped with a seismic damper device.The results revealed that the method successfully optimized the earthquake energy dissipation systems and reduced the effects of earthquakes on structures,which significantly increase the building’s stability and safety during seismic excitation.The analysis results showed a reduction in the seismic response of the structure regarding the formation of plastic hinges in structural members as well as the displacement of each story to approximately 99.63%,60.5%,79.13% and 57.42% for the VSB device,RWD,NCSB device,and MAS device,respectively.This shows that using the PSO-GSA optimization algorithm and optimized damper devices in the structure resulted in no structural damage due to earthquake vibration. | Najad Ayyash Farzad Hejazi | 2022 | Earthquake Engineering and Engineering Vibration2022，21，2： | 1 |
| 4 | Assessment of Aged Offshore Jacket Type Platforms Considering Environmental Loads and Degradation Parameters显示文摘Offshore steel structures are a common investment in oil and gas industries operating in shallow to medium depth seas.These structures have become increasingly popular since the mid-19th century,with a typical design life of 30-50 years.Despite their popularity,the structural integrity of existing offshore structures remains a controversial topic.Environmental loads and material degradation have been identified as significant factors that can compromise the structural integrity of offshore structures.To address this issue,this study aims to investigate the reserved strength capacity of a selected offshore structure located in the Malaysian Seas.The study will explore the effect of oceanographic data,variations in vertical load,and corrosion on the structure’s main members.To determine the impact of each variable on the reserved strength ratio(RSR)of the structure,several pushover analyses were conducted with different variables.Previous literature has shown little or no relationship between seawater wave height,gravity loads,and corrosion allowance on submerged steel members and the RSR of offshore structures.However,this study aims tofill this gap in knowledge by examining these variables’effects on the RSR of offshore structures.The study’sfindings indicate that even a slight increase in wave height can significantly impact the structure’s RSR due to the increase in lateral loading,potentially leading to severe damage to structural components and the foundation model.Additionally,gravity loads had an adverse effect on the RSR of the structure when more than double the vertical load was added.Corrosion allowance was also found to impact the RSR,particularly when assuming significant wall thickness corrosion in primary members.Overall,thefindings of this study have important implications for the design and maintenance of offshore structures.The results suggest that engineers and operators should pay close attention to the potential impacts of environmental loads,such as wave height and gravity loads,and material degradation,such as corrosion allowance,on the structural integrity of offshore structures.This information can be used to optimize the design and maintenance of offshore structures,leading to safer and more efficient operations. | Yazeed Al-Radhi Farzad Hejazi Azmi Abdulkarim Ali Feroozi | 2023 | Structural Durability & Health Monitoring2023，17，2： | 0 |
| 5 | Dynamic evaluation of jack-up platform structure under wave, wind, earthquake and tsunami loads显示文摘Nowadays,the demand for using jack-up platforms to carry out a large percentage of deep-water oil and gas exploration is steadily increasing.The response of jack-up platforms to the severe dynamic loads that may be encountered during the structure life is not examined enough.Therefore,this study attempts to investigate the response of jack-up platforms performance under the effect of dynamic loads due to wave,wind,earthquake and tsunami forces using the finite element method for two models with the lowest and highest hull elevations.The jack-up platform is located in the Gulf of Mexico.Earthquake ac-celerations are applied to the model in high and moderate seismic levels.In addition,tsunami waves are applied to the platform in three different directions at 0°,45°and 90°.This study utilised Airy’s linear wave approach to assess the surface elevations and wave kinematics.The reference wind velocity is 10 knots at 10 m over the mean water level.Results indicate that the dynamic response of the structure is affected by the height of the platform and by the increase of the platform hull elevation.The combination of the El-Centro earthquake,dead and live loads provides the major impact on the platform at the lowest(70 m)and highest(85 m)hull elevations.The comparison of all result proves that the jack-up platform hull under high earthquake intensity and tsunami waves with 45°has experienced maximum deforma-tion.Moreover,raising the deck will increase the response of the dynamic load and displacements but will negatively affect the platform. | Zaid Mohammed Ghazi Imad Shakir Abbood Farzad Hejazi | 2022 | Journal of Ocean Engineering and Science2022，7，1： | 0 |
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