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Dear All, How to validate the long term deflection check in safe from ACI 318-14? Different calculated deflections are generated if we change the options in "Advance Modeling Options" The deflection check (L/480) gets passed if i check only the first option on "Advance Modeling Options" in Safe but it gets failed when the default is check i.e only the last option of ignoring the vertical offsets. Span is 26.75 by 26.75 LL=100psf SDL=60psf 1080lb/ft wall load is taken on the span as indicated on the image. Slab thickness is taken as 7.5in

Assalam O Alykum In one project external consultant IDOM structural engineer is saying that allowable long term deflection ( Flat slab )shall not be checked against the Span length ( center to center) along the longer length but on the diagonal length ( where the maximum deflection occurs) Continuous panel of flat slab 8.3m along horizontal direction and 9.3m along the vertical side and diagonal length is 11.5m. Which one is correct out of 3 to check the allowable long term deflection. Any reference from code. I am seeing ACI code is silent and unable to provide definition of Ln. 1. 8.3x1000/240 = 35mm 2. 9.3x1000/240 = 38.75mm 3. 11.5x1000/240 = 47mm ( might be multiplied by modification factor calculated for compression steel) I am also attaching sketch for better understanding Thank you QUERY.pdf

Beam deflection as shown in Etabs is .757 in . Is it uncracked section immediate deflection or cracked section immediate deflection?? Note All property modifiers are 1 (as default) .

Dear all; I have a very very important issue that related to long term deflection (Cracking Analysis) Using SAFE. I Argued with another Engineer High experienced.So please help me. I am designing a slab 300 mm thick with 2.8 meter Cantilevers. 1. CASE 1 :I want to see the results if I put only the mesh reinforcement T12@20cm. I read the results from SAFE as in Figure 1, deflection = 46.7 mm. (I used the reinforcement source from finite element and minimum reinforcing ratios for tension and compression 0.00256 i.e T12@20cm see figure 2). 2. CASE 2: Now I want to put additional reinforcement to control the deflection.(HERE THE POINT WHERE WE ARGUED ABOUT). I said that I have to put additional reinforcement in tension and compression =T16@10cm , that means I put in min. reinforcing ratios (in SAFE) Tension and compression =0.0095 see Fig. 3 ) In this case the deflection become 31.5 mm) see Fig. 4. 3. CASE 3 : He said that we will put only additional steel T16@10cm in the tension face . But I checked that on SAFE (I put min tension =0.0095 and min compression = 0.00256(the main mesh (see Fig.5) ). The deflection at the contrary increased to be 54.5 mm (Fig. 6) Question To You Dears: What is the right procedure ? that what I did Or What the Engineer did?

Salaikom dear professionals, First of all I would like to express my sincere thanks to the initiators of this forum for establishing such an exceptional atmosphere for knowledge/experience sharing, I it is really useful, In fact since I have found the forum I am mostly online and busy reading the posts. I would also like to thank the members for their professional comments and advice. As my first post in this forum I would like to ask the following queries: 1-After running the analysis and design when I check the DESIGN DATA through Display >> Show Tables >> DESIGN DATA >> Concrete Frame Output, there is no specific message in Column Summary Data and Beam Summary Data, but in Joint summary data it is showing that “Joint B/C check not done”. Does anyone has any idea? I am sharing the ETABS model for your information and easy reference. ETABS MODEL.zip 2- ETABS provides greater area of steel in the upper column than the column at BASE, perhaps due to higher moment. Could someone explain why this is so? In practice should we maintain maximum steel in both stories? Or we shall follow what the software suggests? 3- Beside considering the minimum thickness required for deflection control of Beam as per Table 9.a Chapter 9 ACI-318 , using concrete crack behavior in ETABS and checking story drift, Do we have to check the deflection of beams for the serviceability propose elsewhere in ETBAS? If yes, Could anyone explain it? Regards, and look forward to any explanation

first question is what is the purpose of long term deflection multiplier in safe software? 2. why do we give self weight multiplier while defining laod cases in ETABS?