Leaderboard

Width of thicker mat portion should be sufficient to avoid 'punching'. This is sometimes taken equal to width of column strip, for simplified detailing, and is generally NOT larger than column strip. Following threads also contain some useful discussion related to slab/mat strips: 1. http://www.sepakistan.com/topic/1689-drop-in-mat-foundation/?hl=%2Bcolumn+%2Bstrip#entry4369 2. http://www.sepakistan.com/topic/1612-width-of-design-strips-in-safe/?hl=%2Bcolumn+%2Bstrip Regards.

Is it compulsory to remove rust from lap bars or dowel before pouring concrete,i have heard that rust increases bond between concrete and steel if it is in permissible limit. For more information and sources! https://www.facebook.com/pages/Just-For-Reference-Civil-Engineering/1418113711847117?ref=hl

Wa-alaikum-assalam. See Section 2.3 of the following document: CSI Shear Wall Design Manual (ACI 318-08) (http://www.google.com.pk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0CCcQFjAC&url=http%3A%2F%2Fdocs.csiamerica.com%2Fmanuals%2Fetabs_9.7.2%2FShear%2520Wall%2520Design%2FSWD-ACI-318-08.pdf&ei=q7ygVZb0KIn5ywON-7iICw&usg=AFQjCNEtuaJNcJdb2Gzvi2LEEqrRd-2n1A&bvm=bv.97653015,d.d24)

1. You can check in ETABS analysis manual pdf about these things. These options enforce reinforcement limits according to the selected category. For example if you select sway intermediate/special, ETABS will check for reinf limitations given in ACI chapter 21. 2. Codes explicitly state that, please read again UBC or ASCE. You will find the limits of 0.020/0.025 for seismic. For Wind read commentary of wind chapter at the end of ASCE 7-05/10. Usually the limit is H/400 but you must know on which W to check this limit. Is W service or ultimate. Read about it in the same commentary chapter. Otherwise, you can check this article. Always search the topics before posting a new one. It helps us.

Dear Omer, Do not provide the concealed beam of 9"x9". It will worses the situation. In my opinion 19'x18' is not too big span. If this is a frame structure then you can remove this beam and apply the loading directly on slab as this slab will be having the loading of walls, SDL and any other Live Load. You can increase thickness to 7 inch or or 7.5 inch. In shal ALLAH it will solve your problem. Because 7 or 7.5 inch slab has sufficient resistance to deflection but you can check it in SAFE. If this is a multistory housing (brick masonry) structure, then also use this slab only for the loading of one floor. Try to locate the load bearing points on the upper floor. Apply the loading on the slab and design it as mentioned in above comment. But if you want to provide concealed beam then go for 24"x10.5". In usual construction, the total slab thickness (including concrete slab+ floor finishing ) is 12". So with the mutual understanding with architect you can provide 24" wide beam with 10.5" depth. This will not solve your 100% deflection but it can help. I have provided this kind of beams in too many brick masonry structures. Thanks Muneen