EngrUzair

W. Assalam. In principle, in order to avoid pounding effect (collision of the two buildings during an earth quake), you will need to provide an expansion joint that would be a larger than the maximum drift of both the buildings, at the expansion joint location. I have read somewhere (and If I remember correctly), width of such an expansion joint is LESS than the sum of the maximum drifts of the two buildings. I will have to search for the reference, however, to give you exact relation. You may also go through this post http://www.sepakistan.com/topic/1411-expansion-joint/, containing a good discussion as well a couple of nice references on expansion joints.

Aoa. Internet is a wealth of information, including structural. A smart search on the internet, may help you collect pre-heaters related general information, design procedures and calculations, as well as relevant design codes.

Aoa. You may try it. It may help too, but probably not much. To confirm, try various options one by one and observe their effect on overall behaviour of the member, by comparing with previous results. You will yourself understand what difference each option has made, and to what extent.

Aoa. Sir Umar! Thanks for indirectly reminding me to check my own record dump, as I have found relevant portions of international building supplement to 2009 IBC available with me as well. However, the database includes the same four pakistani cities, as mentioned in your post. I think, I will have to obtain basic snow load data from MET department (as waqar saleem has already pointed out earlier), and to transform it into a reference database table, useful for structural designers. This is however a time-cosuming job and being too busy now-a-days, I will work on it sometimes later. The progress & results of this research will insha-allah be updated on this forum, whenever some noteworthy achievement is made in this regard.

Aoa. IMHO, following are the answers to your questions: A/Q1: You may need to adopt one or more of the following actions: a. increase beam size, b. reduce ties spacing, c. increase diameter of ties, d. use higher yield strength steel for ties A/Q2: You might have used Fixed support on both sides. Try using Hinged support on one side and Pinned support on the other. A/Q3: Required foundation size (area) INCREASES with REDUCTION in soil bearing capacity. For very low bearing capacity, you might have to go for raft footing or piles. In SAFE version 8, you may check two-way shear by using 'Design -> Display punching Shear Ratios' Menu option. A/Q4: Mass is used in dynamic analysis and calculated using formula, m = w / g ; where m is mass, w is weight and g is acceleration due to gravity. A/Q5: 'P-Delta Analysis' is carried out to account for length effects in columns (buckling). On the other hand, 'Dynamic Analysis' is carried out to study the effects of time-varying forces (earthquake etc) on the structure. A/Q6: Concrete compressive strength (f'c) is important for calculating various material properties. On the other hand, strength of concrete depend upon several parameters, like ratio of cement, sand and aggregate; water-cement ratio, age on testing, strength of aggregate, curing method, etc. etc. A/Q7. In SAFE, punching shear results are displayed as a ratio of maximum calculated shear with respect to capacity. A ratio of 1.0 indicates that maximum calculated shear is equal to the maximum capacity of the section. Hope this is helpful.

Aoa. Naeem! I have done a little search on google regarding design examples for lifting hooks and devices, and found following links on the first page of search results. There will be a lot more on later search pages as well. (mostly the designs data is based on ASME BTH (Below The Hook) 1 code) : 1. spreader bar and lug caculations: http://www.pveng.com/ASME/ASME_Samples/ASME_SpreaderBar/ASME_SpreaderBar_Calcs.pdf 2. Lifting lug design: http://www.webcivil.com/stlug.aspx 3. Spreader bar design process: http://www.spartaengineering.com/spreader-bar-design-process/ 4. Below the hook equipment. Has several pdf files about lifting devices.: http://www.avonengineering.com/below-hook-lifting.php etc. etc. Try searching yourself. You may surely get much more relevant data than I have listed above.

Aoa. I have not designed lifting hooks. However, in principle, design of hooks and lifting arrangement should be done in a way, similar to the design of a steel frame. (Deciding a suitable layout for the lifting device and hook., calculating total load to be lifted, determining members, welds, and stiffener sizes , depending upon load distribution to various members and joints...) Design of these lifting devices and hooks, is generally to ensure safety of work people during construction. In USA, generally, OSHA regulations provide basis for the safe design of these devices. A good search on the internet might help you collect specific details relevant to your requirement.

Aoa. asadishaq! The links are working fine, even now. Most probably, you might be having some problem with your web browser, or its settings. Sorry, for replying in place of Rana. However, it is as a third-party cross-check only.

Aoa, Sir Umar! Firstly, I totally agree with the idea of "Consistent Design", for the Pakistani Engineers. BTW, What is the progress achieved on this idea so far? Secondly, IMHO this idea of Consistent Design may be made even more useful, keeping in view following comments: 1. What I have understood from your post, your basic idea is limited to consistent design for UBC-97 and earthquake resistant design ONLY. IMO, this should extend to all other design types, based either on material (concrete, steel, wood etc) or the nature of loading (earthquake, wind, snow, etc) as well. 2. According to my knowledge, although in our country mostly US Design Codes are being used by private consultants or government departments, there is generally no consensus among the structural engineers as to which design codes (British or US) are to be adopted, even for common materials like concrete and steel. In this context, first of all we should decide a standard or 'Consistent' Structural Design Criteria for the proposed 'Consist Design'. This design criteria should include both 'Material design Codes' for the various structural materials (concrete, steel, wood etc) and the 'Loading Codes' (for dead, live, earthquake, wind, snow etc). My recommendations regarding 'Consistent Structural Design Criteria', are as follows: a. We should use US Material Design and Loading codes, being more advanced and progressive. And, also because our national building code, Building Code of Pakistan, is based on US codes. b. In line with above recommendation, specific Material Design codes should be: (1) ACI 318 for Reinforced Concrete Design (2) AISC 360 for Structural Steel Design (3) AISI for Cold-Formed Steel Design c. Specific Loading codes should be: (1) Building Code of Pakistan (Seismic Provisons-2007) and UBC-1997 for Earthquake (Seismic) Loads (2) ASCE 7 for all other (Dead, Live, Wind, Snow) Loads Thirdly, this is a very important and special topic. As such, it should be allotted a separate full forum, and all the relevant posts should be placed in this new forum. Thanks.

Aoa. @Rana! Links in your original post are not working. Can you update them so that anyone interested could benefit from them in future as well? Thanks.

Aoa. You most probably need to use larger sections to improve Kl/r ratio and load carrying capacity of members. As regards modeling of trusses, since you have not mentioned general arrangement of your analysis model, my response is about general aspects of steel structures modeling only. Trusses are also to be modeled similar to frames, after deciding type of truss (fink, pratt etc) to be used. In case you are using 3-d space model with roofing, loads may be applied to roof directly. Alternately, as in case of a 2-d model, loads may also be applied to the top chord joints of the truss, as per the tributory area of the joint.

Aoa. For selection of cold-formed steel design software, you may check here:http://cold-formed-steel.software.informer.com/

Aoa. Moderators: What are your thoughts and recommendations in this regard? Thanks in advance.

Code requirements regarding splicing of reinforcement, including minimum splice length, are given in ACI 318-05 Chapter 12. These requirements are summarised and elaborated with detailed examples in PCA Notes on ACI 318-05. In addition, last article in chapter 5 in 'Design of Concrete Structures' by Nilson provides a good description of reinforcement splicing, along with an example on calculation of compression splice for a column. In general, provision of a splice length less than than that required by the code, will negatively affect the load or moment carrying/transferring capacity of the column. However, extent of this capacity reduction will depend upon detailed analysis and comparison of 'code required length' and the 'actually provided length'.

Aoa. Refer to https://wiki.csiamerica.com/display/etabs/Rigid+vs.+Semi-rigid+diaphragm for detailed information.

Aoa. Sir Umar! What is the difference between the two approaches? Can you refer to some good book or article having relevant examples, dealing with the LRFD approach for foundation design? Thanks in advance.

In general, the consultants carrying out structural design work, would undertake structural evaluation jobs as well. There are a large number of consulting firms in Pakistan. However, all of them might not be having the services of an experienced structural engineer capable of dealing with evaluation work properly. To make sure that you hire a quality engineering firm for your job, the chosen firm should be registered as a Consultant with Pakistan Engineering Council, besides being well reputed in relevant discipline i.e., earthquake related structural evaluation.

Aoa. Keeping in view ACI 318-05 section 21.4.1.2 for special moment frames, a vertical member with 1200x600mm cross sectional dimension should be treated as a "column". Therefore, 1) a "frame' system should be adopted for analysis, 2) the 1200x600mm section should be modelled as a 'frame' or 'column'.

Aoa. Generally, type and adoptable depth of foundation are recommended by the geotechnical engineer, along with allowable bearing capacity etc. In case of soils reclaimed from sea, either piles or raft foundations are recommended along with some additional soil improvement measures. Structural design of for these foundation types are available in foundation design books. Do you have geotechnical soil investigation report of the area, where warehouse is to be constructed? If yes, what does it recommend regarding foundation type and depth? If not, you will have to obtain detailed soil investigation report first, to proceed further.

Aoa. I would suggest to go for MSc WITH thesis option. Thesis option would require some kind of research work, and would help you develop interest for carrying out research in your favourite field and topics. It will be much more helpful in future, in case you decide, to pursue further education (PhD etc) later on.

Aoa. Consult 'Strength of Materials' books. There may be several in UET library. The one in McGraw-Hill's Schaum's Outline Series, by William Nash, might be more helpful in understanding the basic concepts.

Being basically a moment resisting frame, Ct should be taken as .03.

UBC 1997 Section 1630.2.2 relates the Ct value to firstly with material property and then with the structural system. In materials, only Structural Steel and Reinforced Concrete are recognized separately. All other materials, are classified under a single category of 'other buildings'. The structural systems recognized for specific Ct values, are also of two main types; Moment Resisting Frame (SMRF, IMRF etc), for both Steel and Concrete structures., and Eccentrically Braced Frames (EBF) for Steel only. Steel MRF have higher Ct value of .035. On the other hand, Concrete MRF have a lower Ct value of .03. Steel EBF also have a lower Ct value, equal to that for Concrete MRF. All other materials and structural systems have been assigned same low value of Ct = .02. It may be noted that Ct value is used in the approximate and the simpler method (Method A) of calculating time period T of a structure. The time period value obtained in this way is lesser and conservative, as compared to that calculated using more detailed Method B provided in the same section of UBC 1997.

Try searching on Google, using your topic title, with the addition of 'examples' etc.

Aoa. There appears to be some geometric modelling problem, as discontinuity is along only one grid line. All other members, on either side are continuous. Normally this should not happen. Delete the lower side vertical member at along discontinuous grid line, and redrawing in line with upper side vertical member connected to column centroid, might help solve the problem. Otherwise, actual model file may require posting here.