Hamid Ahmadi
Assistant Professor, Faculty of Civil Engineering, University of Tabriz, Tabriz, Iran
[ 1 ] - Evaluating the Seismic Performance of Steel-SMA Hybrid Braces
The seismic performance of hybrid braces composed of steel and shape memory alloy (SMA) was investigated in this paper. Six types of hybrid braces were used, constituted by SMA content of 0, 20, 40, 60, 80, and 100%. A nonlinear dynamic analysis was performed under El Centro earthquake records, with the maximum acceleration of 0.6g and 0.9g. Our results showed that the seismic performance, i.e....
[ 2 ] - Probabilistic Assessment of Pseudo-Static Design of Gravity-Type Quay Walls
Failure of the quay walls due to earthquakes results in severe economic loss. Because of hazards threatening such inexpensive nodes of national and international transportation networks, seismic design of quay walls is still an evolving topic in marine structural engineering. This study investigates the sensitivity of the gravity-type quay wall stability respect to uncertain soil and seismic pr...
[ 3 ] - بررسی رفتار دینامیکی سکوهای فراساحلی شابلونی مجهز به سیستم میراگر مایع تنظیم شده تحت تحریک لرزه‌ای
In the present paper, the effectiveness of Tuned Liquid Damper (TLD) in controlling the dynamic responses of offshore jacket platforms under earthquake excitation is investigated. This type of dampers consisting of one or more fluid (generally water) containers can be installed on the platform’s deck. Hydrodynamic actions induced by the tilting of the water surface in the container act as...
[ 4 ] - تأثیر ناکاملی هندسی عضو مهاری روی ضرایب تمرکز تنش در اتصالات لوله‌ای T شکل سکوهای شابلونی تحت بارگذاری محوری
Brace and chord members of a tubular joint always have a degree of geometrical imperfection due to the manufacturing, transportation and installation processes and also the action of various loads during the lifetime of the structure. However, during the analysis and design of tubular joints, geometrical imperfection is not usually taken into account. Considering the geometrical imperfection in...
[ 5 ] - Parametric Study of SCFs in Unstiffened Gap Tubular KT-joints of Offshore Structures under OPB Moment Loading
In this paper, results extracted from a set of stress analyses performed on 46 FE models for unstiffened gap tubular KT-joints are presented and discussed. The main objective of the FE analyses, validated against experimental data, was to run a parametric investigation on the effects of geometrical characteristics of the joint on the values of the stress concentration factors (SCFs). The SCF is...
[ 6 ] - Experimental and Numerical Investigation of Geometric SCFs in Internally Ring-Stiffened Tubular KT-Joints of Offshore Structures
Tubular KT-joints are quite common in offshore structural design and despite the crucial role of stress concentration factors (SCFs) in evaluating the fatigue performance of tubular joints. However, the SCF distribution in internally ring-stiffened KT-joints have not been investigated and no design equation is currently available to determine the SCFs for this type of joint. In the present pape...
[ 7 ] - ارزیابی قابلیت اعتماد موج شکن های توده سنگی در برابر گسیختگی ناشی از روگذری امواج
گسیختگی ناشی از روگذری، بر اثر سرریز شدن بیش از حد مجاز آب از روی تاج موج شکن رخ می‌دهد. مدل‌های متعددی برای پیش‌بینی روگذری موج در انواع مختلف سازه‌های ساحلی ارائه شده است. تحلیل قابلیت اعتماد سازه با لحاظ کردن عدم قطعیت های موجود در شرایط محیطی و پاسخ سازه، درک بهتری از این مدل‌ها در اختیار طراح سازه گذاشته و این امکان را فراهم میسازد که توازن مناسبی بین تراز ایمنی سازه و هزینه پروژه ایجاد...
[ 8 ] - Stress Concentration Factors in Uniplanar Tubular KT-Joints of Jacket Structures Subjected to In-Plane Bending Loads
In the present research, data extracted from the stress analysis of 46 finite element models, verified using test results obtained from an experimental investigation, were used to study the effect of geometrical parameters on the chord-side stress concentration factors (SCFs) of central and outer braces in uniplanar tubular KT-joints of offshore structures subjected to four different types of i...
[ 9 ] - Degree of Bending (DoB) in Tubular KT-Joints of Jacket Structures Subjected to Axial Loads
The fatigue life of tubular joints commonly found in offshore industry is not only dependent on the value of Hot-spot stress (HSS), but is also significantly influenced by the through-the-thickness stress distribution characterized by the degree of bending (DoB). The determination of DoB values in a tubular joint is essential for improving the accuracy of fatigue life estimation using the stres...
[ 10 ] - ارزیابی حساسیت مقاومت استاتیکی اتصالات لوله ای K سکوهای فراساحلی جکتی نسبت به عوامل تصادفی مؤثر بر مبنای تحلیل قابلیت اعتماد
هدف این پژوهش، تحلیل حساسیت و تعیین مهم ترین عوامل تاثیرگذار در طراحی اتصالات لوله ای تک صفحه ای K، بر اساس تحلیل قابلیت اعتماد است. در این مطالعه، تمامی پارامترهای تأثیرگذار روی مقاومت استاتیکی اتصال و همچنین نیروهای داخلی به عنوان متغیرهای تصادفی در نظر گرفته شده و میزان تأثیر عدم قطعیت های مختلف روی احتمال شکست اتصال K بر اساس معیار گسیختگی تسلیم بررسی شده است. تابع احتمال حاکم بر نیروهای ...
[ 11 ] - Reliability analysis of rubble-mound breakwaters against the failure due to the armor layer instability based on the fuzzy random variables theory: A case study of Anzali Port breakwater
Breakwaters are among the most frequently-used coastal protective structures and their stability is vital to avoid turbulence at the ports. The main purpose of the present research is to use the theory of fuzzy random variables and the second-order reliability method (SORM) to study the reliability of a rubble-mound breakwater against the failure due to the armor layer instability. The limit-st...