Good Tutorial CEE. With respect to the mode shapes, I had to do two things per your recommendation. Firstly, I had to increase the stiffness of all the beams in all 3 direction by 4x, which somehow worked. But I don’t like the idea. Secondly, I had to model the structure close to the real structure by inserting some slabs in the building to increase the floor stiffness. And almost all the mode shapes made sense as per my expectations. With regard to the time history tutorial, I had to read in one of the default time histories that comes with RSAP just to avoid any potential bug 🐛 that might slow me down. However I have one question which I need your clarification, with regards to determing the Mass (alpha) and Stiffness ( Beta) proportional parameters, what’s the basis for selecting the 2nd mode frequency for (w1) and the arbitrary circular frequency (w2).? In practice, will it be adequate to pick the first and the last modal frequency for w1 and w2 respectively? Am so appreciative of the fact that you had to literally go through hell to make your viewers happy with your timely tutorials. Excellent 💯 tutorials Sir Thank you Regards
Hello there, I am glad you liked it. True, a full structure is to be modeled (with slabs) so that mode shapes to make more sense. I expect that the strange diagonal shapes will be eliminated because the axial stiffness of the slabs will resist such modes. as for w1 and w2, w1 is the 1st frequency, w2 is the 2nd frequency, I just simply "assumed" a value for it. I should have taken it out from the mode shapes. thanks a lot for your comment, it encourages me to do my absolute best. Regards, CEE
Hi Sir CEE; Have 2 question -The first one is related to how to insert columns for spaces where there are curtain walls. Usually for a structure that only has brick walls, we insert columns inside the brick walls and cover it with finishes which makes the axes of the slabs pass through the axes of the beams and columns. but for curtain walls, the column are behind the walls. How can we take into account this for the different axes for load trasfert of structural systems?? -The second question is can we perform static + dynamic load combination?? Like for the structure you corrected, there is one part of the structure ( generator room) which causes vibration of the structure. How to take into account the static and dynamic loads Hope to get a response🙏 Boris
If you want to insert a column at a curtain wall, you would need to replace the curtain wall. However, please notice that "shear walls" can be used to carry vertical loads totally fine. Actually, I do encourage to use your shear walls to carry vertical loads as it will have a positive effect on its moment and shear load capacity. You can do a static dynamic load combination. The question here is: are there combinations in the code that need that? I have not seen this before. Regards, CEE
Hello dear Engr. unfortunately, no. The accidental eccentricity is available under the "seismic" and "seismic (Equivalent Lat. Force)". Time history analysis does not include this, unfortunately. A work-around is really hard but includes manually defining the selfweight as deadload in such a way that the centroid of forces is at 5% eccentricity. This - of course - is a nightmare in modeling. Regards, CEE
@@CivilEngineeringEssentials And it is actually quite tough to do as well for time history analysis in other software such as ETABS. A workaround there however is by shifting the story center of mass from the mass source dialog. I guess Robot do not provide such override in mass source definition and mostly done automatically right? Or is there any way to do so? Thanks for your help 😁
Hello there, unfortunately, there is no such option in Autodesk Robot. I checked almost every corner I know in the software. Anyways, feel free to ask anything. I will try my best to answer any comments as soon as I can.
شكرا لك بروفسور على هذا الفيديو الرائع... سؤالي هل يمكنني القيام بعمل تحليل ديناميكي لا خطي سواء بطريقة التكامل المباشر Direct integration او بالطريقة السريعة من انماط الاهتزازا FNA كيف يتم ذلك؟؟ و هل هنالك خاصية في الروبوت لمطابقة السجل الزمني مع طيف الاستجابة الهدف؟؟ شكرا جزيلا لك
العفو، الروبوت بيشتغل تحليل ديناميكي لا خطي، دون التكامل المباشر، هشرحه في سلسلة التحليل اللاخطي (لكن يحتاج بعض الوقت للوصول لذلك المستوى، لأنه حاليا بدأت في الأساسيات) حتى أفهمك بشكل صحيح، لو كان قصدك implicit explicit integration ففعلاً الروبوت عنده بعض الخيارات بالخصوص، لما تفتح ال Time History Analysis بعد ما تعرفه، تروح على بنفس النافذة، في شيء اسمه Parameters هناك بتقدر تحدد Method of Integration وأيضاً بتقدر تدخل في التحليل اللاخطي (هناك خيارات بالخصوص( بخصوص مطابقة السجل الزمني بالطيف، تقصد time history to match the modes and mode shapes ما في، إنت مضطر تدخل ذلك بنفسك من خلال دالة ال sine or cosine or anything harmonic برضو موجود تحليل ال Harmonics لكن لا أعتقد إنه هذا قصدك أتمنى أكون أفدتك، بالتوفيق أخي الكريم.
تمام بروفسور شكرا لك انا حاولت القيام بذلك لكن على يبدو ان الملف الذي يقبل برنامج روبوت بتصديره للسجل الزلزالي يختلف عن الملف المستخدم في ايتابس..انا بانتظار هذه الطرق الحديثة في التحليل الزلزالي من حضرتك و متشوق لتعلمها منك...شكرا جزيلا لك@@CivilEngineeringEssentials
و ما قصدته عن مطابقة السجل الزلزالي مع طيف الاستجابة هي عملية ال Scaling المذكورة في الكود الامريكي...حتى كما في برنامج ايتابس Match with response spectrum
