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oai:www.ideals.illinois.edu:2142/23462 2023-07-10 col_2142_5131 col_2142_14770 com_2142_5130 com_2142_3518 com_2142_234

Gamble, William L. Kayani, M. Khaliq-ur-Rashid 2011-05-07T14:15:04Z 2011-05-07T14:15:04Z 10000-01-01 1992 Six specimens were tested to investigate the effects on high strength concrete columns due to the presence of ordinary strength floor concrete layer in between. The specimens consisted of four sandwiched type of columns and two edge columns. The four columns, 55 in. long, had a 7 in. layer of floor concrete. These column specimens were designed to study the influence of longitudinal as well as lateral steel on the strength characteristics and behavior of the floor concrete. Two edge columns specimens consisted of two column sections separated by a 7 in. floor slab extending beyond the column faces in three directions. The data from these tests combined with the previously reported similar studies was analyzed to find the appropriate parameters for the estimation of the apparent strength of the floor concrete to be used in the calculation of load carrying capacity of columns. The analysis reveals that Sec. 10.13 of the ACI code is not based on the appropriate parameters. The allowable ratio of 1.4 between the two concrete strengths within which there is no requirement to reduce the column capacity is not considered appropriate. Similarly, the calculation of the apparent floor concrete strength in case of interior columns as per Sec. 10.13.3 was also found to be too unconservative. Mechanics of materials approach used for the analysis of the composite materials was applied for theoretical analysis of the problem. This approach with the use of the available test data lead to an expression for the calculation of the apparent floor concrete strength applicable to all kinds of columns in structures. A similar but simpler and more conservative expression was also devised purely on data analysis. These empirical relationships can be expressed as$$f\sbsp{cp}{\prime} = 2.0\ \lambda\sb{G}\ {f\sbsp{cc}{\prime}\ f\sbsp{cf}{\prime}\over f\sbsp{cc}{\prime} + f\sbsp{cf}{\prime}}$$The concrete strengths in the above equation are replaced by their square roots in the expression deduced from the mechanics of materials approach. Made available in DSpace on 2011-05-07T14:15:04Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9215836.pdf: 3967685 bytes, checksum: a0efca5c19e8640ee87c2cc2dc574cab (MD5) Previous issue date: 1992 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:04:38Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:30:54-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission U of I Only AAI9215836 (UMI)AAI9215836 http://hdl.handle.net/2142/23462 eng Copyright 1992 Kayani, M. Khaliq-ur-Rashid Engineering, Civil Engineering, Materials Science Load transfer from high-strength concrete columns through lower strength concrete slabs text Civil and Environmental Engineering Civil and Environmental Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.