khalid

Batoul Mass source is used for determining the effective seismic weight of the structure for calculating the Seismic Base Shear. Below is the snap shot of ASCE7-05 definition. In Etabs you will have three options. Not to confuse You should do one of the following NOT both: 1) From loads only Dead Superdead Live 1) From specified mass and loads Superdead Live If you put your Dead load in as a load to be considered and you still count your specified mass you will have your DL be twice.

Thank you! As per my understanding in the T-Beams the slab serves as the top flange of the beam but in our case, the inverted beam (Rectangular), the slab no longer serve as top flange. Also in inverted Rectangular Beam the stirrups will be additionally subjected to tension transferred from the hanging slab hence this should be considered in the design. I could not catch your instruction on how to draw the inverted beam or maybe there is no option for them in Etabs 2010 :/ I should design it manually. Does this also affect the hanging slab behavior?

Salam Alaikom fellow Engineers! I have found the "The Seismic Performance of RC Frame Buildings with Masonry Infill Walls" article very useful. So I would like to share it with you, especially for junior structure design engineers. Regards The Seismic Performance of RC Frame Buildings with Masonry Infill Walls.pdf

Salam Alaikom Dear professionals! Kindly please help me with the following uncertainties and questions I faced with developing the attached model Etabs model: There are some long span (18m) inverted or up-stand beams provided to insure enough headroom in the story bellow. How can I model such kinds of beams in Etabs? How much they are structurally similar to conventional beams? What are the significant effects of shear wall meshing on the structural behavior and the design results? In term of computational efficiency, how much should be the mesh size? What is the proper way of supporting the beam over the shear wall and the grid beam? Does Etabs take care of column’s slenderness? Also if you could take your invaluable time to check the model and give me your professional comments and feedback, which would be highly appreciated! Thanks and Best Regards Trial I.EDB

Counrt me in! I will be counting down days! Cheers Khalid

Sir Rana, Who is the instructor of the the online courses? If you, definitely it is invaluable. Please let us know if the online course is going to be conducted. Thanks

Very well explained, looking forward more from you. Thank you so much!

Dear Waqas Haider, If you could upload your model it would be appreciated.

Thank you so much for your very useful information.

Rana Bahai, …. I am wondering that how changing the type of slab to Shell and Membrane can change the design result this much. In Shell type slab there is no specific message and error on Beam/Column joint capacity ratio except the very less amount of steel bar of Beams. As you advised and In order to be on safe side I defined the slab as Membrane and ignored the out-of-plane stiffness of the slab, but after running the analysis amount of designed reinforcement is remarkably changing and the “Beam Column Capacity Ratio Exceeding the limits” is also appeared, while this message was not there in Shell type slab. I got confused with this , your help is highly appreciated.

Dear Engineer Sahib Junaid, Thank you very much for your valuable inputs. I revised the model accordingly, but when I am defining the slab type as Mesh, the following problems in the model appear: 1- The value of designed reinforcement is far away from manual calculation and the values which are calculated for Membrane type slab. 2- In Shell type slab there is no specific message and error on Beam/Column joint capacity ratio, but when I am changing the slab type to Membrane some it is different. Regards Khalid

Thank you sir Umar for providing the link. Sir Rana, The building which I am designing is located in seismic zone III (SS=1.28 S1=0.51), thus Beam Column Joint Capacity is a must.

Thanks Sir Rana, your detailed and helpful explanation has cleared my doubts on two questions (2,3)....... PERFECT In question No.1 there may be some problem in modeling which I couldn't find out Please could check the model and give a brief explanation on that too. Thank you very much again for having spent your time in making me more correct.

Thank you very much Sir Rana, 3- Mean that I should also check the beams deflection for (1D.L + 1L.L) load combination in SAFE and compare the calculated deflection with MAXIMUM PERMISSIBLE COMPUTED DEFLECTIONS as in table 9.5.b of ACI 318. Please correct me sir if I am wrong.