Leaderboard

Assalam-o-alaikum! In the USA, no one can start working as an engineer, just by graduating from an accredited engineering university in civil (or some other) engineering discipline. Rather, each engineer has to pass a comprehensive examination, called Fundamentals of Engineering (FE) Exam, before he/she is eligible for joining some government or private consulting organizations as Engineering Intern (EI) or Engineer-in-Training (EIT), for gaining relevant professional experience to work as independent engineer later on. This exam covers and reviews all the basic subjects, a freshly graduated engineer is expected to have studied in the university during the engineering education. The FE exam is a closed book exam, except that 'FE Reference handbook' (a standard booklet, developed by NCEES_ the exam developing and conducting organization), is the only source material the examinees may consult during the exam. FE reference handbook gives a very good overview of the type and extent of basic technical knowledge (subjects, tables, formulas, equations etc) and concepts, a fresh graduate engineer (whether civil/structural, or any other) must have, to enter into practical engineering field in a technologically advanced country, like USA. The study of 'Civil engineering' portion of this handbook and relevant 'exam specification' at the end, may help us understand level of engineering knowledge we should have, as well as the subject areas requiring improvement of knowledge and strengthening of concepts, in order to make us better engineers. FE Reference Handbook may be downloaded from NCEES website,using following link, free of cost. : http://ncees.org/exams/study-materials/download-fe-supplied-reference-handbook/ Note: You will have to enter your email address in the space provided on the above webpage, and to press 'Submit email' button. The site will send you a password on your given email address. You need to provide this password (on the above webpage) in order to obtain/unlock download link of the FE handbook. Regards.

oho bhai reinforcement type has nothing to do with the type of FEM element you select. You can provide the reinforcement in center part as you have shown in image. But for analysis I would recommend you to model it as slab. Then provide reinforcement details as done in beams but take results from this slab element in SAFE

That is a great book!

Well it replicated self weight. Just delete it. Let me also just ask CSI ppl about this and update you later on.

Finite Element Modelling for Stress Analysis by Robert D Cook

First picture is for the strap beam, you can design it manually (see Nilson book for it) or model it in SAFE. just draw as Umar said, a slab area with equal width to that of strap beam. Dont apply soil supports to strap beam. If you need an excel sheet based on imperial units tell me, I prepared it some time ago. Second picture shows isolated column thickening with basement slab. You can model this as told in first step. The only difference is you will apply soil supports to basement slab too. Just draw isolated column footing with a thickness, and then draw basement slab with its thickness. Third picture shows strip foundation for columns, same modelling procedure will be adopted. Draw strip foundations and apply supports.

2- Upper columns will have higher moment and less axial force so more area of steel. Yes you could provide different reinforcement in upper and lower stories as per your design. 3-yes you have to check serviceability for beams. Code minimum thicknesses are "deemed" to be okay but its independent of loading magnitude. You can check long term deflection on actual loading in SAFE.

For the first picture(strap type), I would model the foundation and beam in ETABS, get the reactions at foundation and export them to Safe. Beam gets designed in ETABS and foundation goes to Safe with loads representing effect of beam presence. Second and third pictures are easy, you can take average thickness and use them. I haven't used Safe in over 5 years now so. I am not sure if there has been a new feature to accommodate such fdns but I don't see any problem there. Use simple slabs with conservative thicknesses.

Assalam-o-alaikum! The same R21.1.1 tells us that "The design and detailing requirements should be compatible with the level of energy dissipation (or toughness) assumed in the computation of the design earthquake forces." This implies that higher the SDC (seismic design category), more stringent will be the design and detailing requirements (in order the structure to have more toughness (energy dissipation). Structural systems permitted in higher SDCs, have higher R values, resulting in a lower seismic design force. So, when you use a structural system required in a higher SDC (( e.g. 'special moment frame'), for a structure in a lower SDC (where normally an 'ordinary' or 'intermediate' moment frame is required), calculated design force will be lower. And, it is permitted by the code. You will however have to design and detail for the adopted frame system, as you would normally do in the case a structure ACTUALLY LOCATED in higher SDC. Regards.

Span of the diaphragm is the distance between vertical lateral load resisting elements. Yes, the same diaphragm can behave different in different directions. Also read and understand following statement from the article: The statement implies that when your are using shear walls in the building, the span of the diaphragm could be the distance (perpendicular to the lateral force) between shear walls, depending upon the relative stiffness of moment resisting frames and shear walls. If the building has no shear walls, then the span is the distance (perpendicular to the lateral force) between column lines, or two consecutive frames.

Yes, slab connects all the lateral forces resisting elements and acts as diaphragm. Further Reading: http://www.sepakistan.com/topic/87-diaphragm/ http://www.sepakistan.com/topic/1480-diaphragm-flexibility/ Thanks.