mhdhamood

Senior Engineers; Can you provide us by the procedure for thermal design of buildings. Such as what to do in ETABS and SAFE, and what to do about modifiers of elements. regards

Hi; In ETABS model for designing columns and shear walls(because slabs will be desined on SAFE), I want to reduce m11=m22=m12=f11=f22=f22=0.25 Can I? (Semi rigid diaphragm assigned) thats because I want to design the building at same model for temperature and seimic and wind loads.

THANKS ENGINEER

Yes Rana Waseem; The seismic load design is not required by municipality for this one story. But even though the point which I want to say is that the main designer neglected the moments at beam column connection that leads to a weak connection that doesn't resist any small moments coming from any lateral loads. This one story is composed of columns +beams + post tension slab only no shear walls.

Dear all; I have one story- I found that the designer designed the columns only for axial loads neglected the moments from slabs... well I thinks it will work in case of gravity loads only. But this system will not carry a 1 Newton lateral load since its unstable system against lateral loads because the column model will be hinge at the top and pin at the bottom. please lets know your opinions

But in ACI-code it doesnt have any procedure or indication that we have to consider it

Dears; do we consider slenderness in designing shear walls , say I have 1.5*0.3 m sectio with height of 6 meters?

Dear Engineer; Yeah I have uploaded regards S402 1ST FLOOR SLAB LAYOUT-Model.pdf

Dears; i am attaching a cad file for this structural system.. please discuss if you have comments on this structural system regards S402 1ST FLOOR SLAB LAYOUT.rar

Dear Senior Engineers; when I design slabs in SAFE I dont modify the stiffness of any memebers. I am now asking what if I want to reduce the stiffness of inplane of the slabs , and then design , Can I?

THANSKS FOR OUR KIND COOPERATION DEAR ENGINEER

Eng. Uzair; even I imported to etabs simple floor that is meshed by robot then to cad then to etabs.......... too much errors same appeared see the attached regards

THIS IS THE SLAB ARRABGMET

ENGINEERS; I WILL LOOSE MY BRAIN FROM ETABS. I DECIDED TO MAKE MANUAL MESHING FROM AREA ELEMENTS BESIDE EACH OTHER AND EVERY HING WAS FINE . BUT AFTER DEVISION SAY 7*7 ELEMNTS FOR EVERY BIG ELEMENT AND MAKING ETABS CHECH..................THEN 500 ERROR MESSAGE THAT ALL ELEMNTS ARE CLOSE TO EACH OTHER. WHAT ARE GOING...... SOMEONE TELL ME PLEASE...... I WILL LOST MY WORK

THANKS ENGINEERS; I WILL SAY WHAT WE DO (MAY BE OUR APPROACH IS CONSERVATIVE): 1.IS ASSIGNING TEMPERATURE OF 25 C ONLY TO THE SLABS (NOT TO COLUMNS, SHEAR WALLS AND BEAMS) . 2.THE STIFFNESS MODIFIERS FOR THE SLAB M11=M22=M12=F11=F22=F12=0.25 (HERE THE NEW THING THE F11,F22 AND F12 MODIFIERS, IN THE MODEL WITHOUT TEMPERATURE NO SUCH MODIFIERS , I AM SURPRISING HERE BECAUSE THESE IN PLANE MODIFIERS WILL REDUCE THE EFFECT OF EARTHQUAKE SOMEWHAT, SO IT IS ACCEPTABLE TO USE THEM IN THE SAME MODEL TO CHECK AGAINST EARTHQUAKE?).

YES IT IS TENSILE .... sO IT WILL BE DESIGNED AS COLUMN??? BUT DOES THE TEMPERATURE CREATES HIGH VALUES LIKE THIS ??IF YES THEN IN SUCH BUILDINGS WE NEED TO CHECK EVERY BEAM IF IT HAS HIGH AXIAL FORCES THEN DESIGN IT AS CLOUMNS??

Engineers; I have a big question!!!!!! when I put the thermal load on slabs , I have found the axial load in the beams is increased for intersting values like 1000 kn why its too much. Then the beams now may not be treated as beams since the axial load more than the 0.1AFc permitted by code. Do I have to design it as columns?

Any one can help please

Dears; I want your kind opinions about modelling raft at different levels; here in UAE there are engineers model it on SAFE as to be on 1 level; But I am wondering why is that since the moment at the connection between two levels will not be the same as if it was modeled at 2 levls May all experts arise there discussion here please; regards

thanks a lot Engineer Umar great

friends: What are the temperature gradient for slab in dubai? someone suggest to put change in temperature at top face 50 c and change in temperature at bottom face 25 c?

Engineer Uzair; I dont mean the drop panel .

Dears ; THANKS FOR EVERY MEMBER IN THIS GREAT FORUM WHO SPENDS HIS TIME O GIVE ANSWERS. MAY YOU ANSWER MY ISSUE 1.in fig.(drop2) ;can the drop in slab be like shown exactly or it is preferable to be over column exactly,and why? 2.fig.(drop in slab); can the drop also be at the midspan? 3. how to account for the drop in desgin ?what is the considerations to take? I mean it will give additional weight . 4. Is there an obligatory locations for the drops? 5. is the detailing of steel fine to account for the stresses and development length? may give expanded discussion please. 6. To what difference in level between two slabs can we use this section as attached and how to guess the (x and y) dimenions?

thanks sir

but for different owners. and in case of not same time of construction.