مطالعه ي عددي اتصالي نوين به صورت كاملاً پيچي به منظور اتصال گيردار تير به ستون با استفاده از مقاطع سپري شكل و نبشي جان

Numerical study of a novel bolted moment connection for the beam to column connection using T-shapes and web angle sections

با توجه به تجربيات گذشته‌ي مهندسان، معمولاً اتصال‌هاي جوشي در هنگام زلزله، عملكرد مناسبي از خود نشان نمي‌دهند. با وجود اين، در همه‌ي اتصال‌هاي گيردار از پيش تأييد صلاحيت شده‌ي موجود در مبحث دهم مقررات ملي ساختمان به نحوي از جوش استفاده شده است. به همين دليل در نوشتار حاضر، به بررسي يك نوع اتصال گيردار كاملاً پيچي با استفاده از مقاطع سپري‌شكل و نبشي جان پرداخته شده است. ابتدا به كمك مدل‌سازي اجزاء محدود و روش اجزاء تشكيل‌دهنده،شيوه‌يي براي محاسبه‌ي سختي و مقاومت اتصال ارائه شده و پس از طراحي تعداد زيادي اتصال و محاسبه‌ي سختي آنها، با استفاده از الگوريتم يادگيري رگرسيون خطي چندگانه، يك مدل ساده براي محاسبه‌ي سختي اتصال ارائه شده است، كه نتايج نشان‌دهنده‌ي خطاي ناچيز مدل مذكور در محاسبه‌ي سختي اتصال است. همچنين اتصال مورد نظر از نظر صلبيت نيز بررسي شده است، كه نتايج نشان‌دهنده‌ي عملكرد صلب آن است.

Based on the past experience of engineers, welded connections usually do not perform well during earthquakes. Nevertheless, welding is used in all prequalified moment connections in chapter 10 of the National Building Code of Iran and as a result, there is a need for a fully-bolted prequalified moment connection for use in intermediate moment frames (IMF) and special moment frames (SMF). Thus, in this paper, a novel type of fully-bolted connection was investigated using T-shaped sections and web angles. First, the finite element model of the connection was developed in Abaqus software and validated with respect to experimental results. Next, using the concepts of Eurocode 3, section 1-8, a method for calculating the stiffness and strength of the connection was presented and was validated with the help of several experimental tests and finite element modeling. The results confirmed the proper performance of this method in predicting the stiffness of the connection. Since finite element modeling and experimental tests require a lot of cost and time, the proposed method can be a good option for engineers. Next, with the aim of parametric study on the connection, a large number of connections were designed based on capacity. Based on the component method, the connections stiffness was calculated using supervised machine learning techniques and multiple linear regression learning algorithm. Next, using the data obtained from the design and component method, a parametric study was performed on the connection and a simple formula was presented to calculate the initial stiffness of the connection. The results of this study show excellent regression performance in predicting connection stiffness. In addition, according to the obtained formula, the depth of the beam and diameter of the bolts connecting the T-shape flanges to the column flange have the most impact on the connection stiffness. Finally, the studied connection was classified according to its rigidity. The results showed that the studied connection acted as a fully-restrained connection and can be used in IMF and SMF systems.