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بررسی اثرات دال، خروج از مرکزیت و تیرهای عرضی بر روی رفتار لرزه¬ای اتصالات تیر به ستون بتنی (مطالعه آزمایشگاهی) Assessing the impact of eccentricity, slabs, and transverse beams on the behavior of reinforced concrete beam-column joints Myeong-Ho Choi a, Chang-Hwan Lee b,* a Division of Architectural and Fire Protection Engineering, Pukyong National University, 45, Yongso-ro, Nam-gu, Busan 48513, Republic of Korea b Department of Architectural Engineering, Pukyong National University, 45, Yongso-ro, Nam-gu, Busan 48513, Republic of Korea A B S T R A C T In this study, a cyclic lateral load experiment was performed to assess the behavior of reinforced concrete (RC) beam-column joints with non-seismic detailing. For the experiment, eight full-scale joint specimens were prepared; the experimental variables were eccentricity, presence of slabs, and number of transverse beams. Most experimental objects showed joint shear failure after beam yielding, and their eccentricity reduced the joint shear strength. Although the joints had non-seismic details, the presence of the slabs and increased number of transverse beams strengthened the confinement within the joints, thereby enhancing the joint shear strength. The joint shear strength that was calculated based on the equation suggested in ASCE 41-17 showed a substantial discrepancy from the actual measurement, primarily because the calculation neglected the impact of the slabs and number of transverse beams. Therefore, to improve the performance prediction, an actual three-dimensional shape of the joints must be considered. Additionally, based on further research outcomes, more factors that affect joint behavior must be considered in future relevant standards. ✍️ اثرات دال در مقاومت چشمه اتصال 🔻 مقاله ضمیمه شده یک کار آزمایشگاهی ارزشمند بر روی رفتار لرزه‌ای اتصالات تیر به ستون بتنی است که مطالعه آن به همکاران توصیه می‌شود که در آن 8 نمونه اتصال تیر به ستون بتنی جهت بررسی اثرات دال بر روی مقاومت چشمه اتصال تحت آزمایش شبیه استاتیکی چرخه‌ای (cyclic loading) قرار گرفته‌اند. 🔹 هرچند ممکن است برخی همکاران حوصله مطالعه آن را نداشته باشند :)، نتایج آن به‌طور خلاصه به شرح زیر است: 1- مقاومت چشمه اتصال برای یک اتصال میانی در حالتی که دال حضور دارد حدود 37 درصد! بیشتر از حالتی است که دال حضور نداشته باشد. همین نسبت برای یک اتصال خارجی حدود 16 درصد! مشاهده شده است. 2- حضور دال منجر به خنثی کردن اثرات منفی خروج از مرکزیت‌ تیرها نسبت به محور مرکزی ستون‌ها می‌شود. به عبارتی، نتایج نشان داده‌اند که در صورت حضور دال، خروج از مرکزیت تیرها تأثیر چندانی روی مقاومت چشمه اتصال نخواهند داشت. 🔹 نتیجه اینکه در صورت حضور دال، مقاومت چشمه اتصال به شکل قابل‌توجهی بهبود میابد که با روابط ASCE 41-17 نیز مقایسه شده است. این در حالی است که آیین‌نامه‌ها نظیر ASCE 41-17 و ACI 318-19 در محاسبه مقاومت چشمه اتصال اصلاً اثرات دال را مشارکت نمی‌دهند و از اثرات مفید آن صرف‌نظر شده است؛ که یکی از دلایل آن عدم وجود مطالعات آزمایشگاهی کافی بوده است. منبع دانلود

Numerical and experimental study of the BUEEP connection using an inner box Seyed Mahdi Rafiei Tekieh a, Amir Peyman Zandi a,*, Malek Houshang Pashaei b a Department of Civil Engineering, K.N. Toosi University of Technology, Tehran, Iran b Structural Engineer, Ista Gouya Consulting Engineers, Tehran, Iran A R T I C L E I N F O Keywords: Inner box Continuity plate Box-column Moment steel connection Bolted extended end-plate connection Cyclic test A B S T R A C T In this paper, a prefabricated part called Inner Box is proposed to be embedded in box-columns at the connection zones to solve the well-known problems of the box-column connections, namely the inaccessibility of the interior side of the box-columns for both continuity plates welding and bolt tightening. The inner box contains four sideplates and two continuity plates assembled like a cube. Nuts are encased with specially designed gadgets welded to inner box side-plates preparing for a direct bolted connection. Fabrication, nondestructive tests, and repairs of typical inner boxes are practically and economically justified. For optimization study on IB dimensions, nonlinear finite element modeling is used. Then a full-scale specimen of the optimized connection is tested under cyclic loading. Test results, according to AISC 341–22, approve the connection’s seismic qualification in the range of the tested dimensions. The test specimen and FEM models show good agreement. Finally, some design criteria are proposed by numerical sensitivity studies. منبع دانلود

Quasi-static cyclic tests on super-lightweight EPS concrete shear walls Seyed Amin Mousavi a,⇑, Seyed Mehdi Zahrai b,c, Asghar Bahrami-Rad d a School of Civil Engineering, University of Tehran, Tehran, Iran b Center of Excellence for Engineering and Management of Civil Infrastructures, School of Civil Engineering, Faculty of Engineering, The University of Tehran, Tehran, Iran c University of Ottawa, Ont., Canada d Department of Civil and Environmental Engineering, AmirKabir University of Technology, Tehran, Iran a r t i c l e i n f o Article history: Received 13 May 2013 Revised 1 February 2014 Accepted 3 February 2014 Keywords: JK wall Lightweight concrete Low strength concrete EPS concrete Cyclic test Shear wall a b s t r a c t This study introduces a new emerging structural system, called JK system, which uses JK walls as its main structural elements. JK wall, first proposed by Joseph Kiefer, is a kind of shear wall constructed with lowstrength/ super-lightweight Expanded Polystyrene (EPS) concrete and reinforced by JK panel, JK stiffener and some additional steel rebars. The study experimentally examines behavior of three JK wall specimens with different reinforcement and level of gravity loads under quasi-static cyclic loading. Obtained results indicate that JK walls can sustain large ductility demands accompanied by stable hysteresis loops. All specimens are also numerically investigated in order to obtain a reliable analytical tool. In this paper, it is shown that a low-strength concrete, currently recognized as a nonstructural material, can be used as a structural concrete having a satisfactory behavior. Finally, a seven story building with JK system is considered to numerically study the above claim. However, more studies are still required to fully capture all short and long term features of structural EPS concrete elements. Engineering Structures 65 (2014) 62–75 منبع: [Hidden Content] دانلود: [Hidden Content] iiG1ypg_.pdf