Search

Analyses on RC frames designed as per the Indian standards (IS 1893:2002 and IS 13920:1993 (2008)) and draft proposal (IITK-GSDMA EQ 11 v 4.0, 2008) are done in this paper. Based on the results, certain provisions in the latest codes (IS 1893:2016 and IS 13920:2016) are reviewed. The study is focused on frames with vertical geometric irregularity. However, analyses of regular frames are also done to make certain comparisons. The necessity of strengthening/retrofitting for the buildings located in places whose seismic zones are revised as per IS 1893:2002 is also examined. Regular structures are found to sustain the earthquake events with sufficient safety. The design of regular frames can be made more economic by reducing their design base shear. The column/beam moment-capacity ratio (M.R.) in IS 13920:2016 is found uneconomical for regular frames. Improvements to the design of irregular frames can be made by reducing their response reduction (R) factors and following the M.R. value of 1.4 adopted in the recent code (13920:2016).

Many studies in the past on dynamic soil–structure interactions have revealed the detrimental and advantageous effects of soil flexibility. Based on such studies, the design response spectra of international seismic codes are being improved worldwide. The improvements required for the short period range of the design response spectra in the Indian seismic code (IS 1893:2002) are presented in this paper. As the recent code revisions has not incorporated the short period amplifications, proposals given in this paper are equally applicable for the latest code also (IS 1893:2016). Analyses of single degree of freedom systems are performed to predict the required improvements. The proposed modifications to the constant acceleration portion of the spectra are evaluated with respect to the current design spectra in Eurocode 8.

Thin films of manganese-doped cadmium oxide (CdO:Mn) with different Mn-doping levels (0, 1, 2, 3 and 4 at.%) were deposited on glass substrates by employing an inexpensive, simplified spray technique using a perfume atomizer at 375 °C. The influence of Mn incorporation on the structural, morphological, optical and electrical properties of CdO films has been studied. All the films exhibit cubic crystal structure with a (1 1 1) preferential orientation. Mn-doping causes a slight shift of the (1 1 1) diffraction peak towards higher angle. The crystallite size of the films is found to decrease from 34.63 nm to 17.68 nm with an increase in Mn doping concentration. The CdO:Mn film coated with 1 at.% Mn exhibit a high transparency of nearly 90 % which decreases for higher doping concentration. The optical band gap decreases with an increase in Mn doping concentration. All the films have electrical resistivity of the order of 10−4Ω·cm.

Crystalline SnO2 – TiO2 thin films were deposited on glass substrates by using the precursor solution containing tin acetate and calcium titanate as the source materials. After the deposition, the films were subjected to annealing at two different temperatures of 150o C and 3000 C. The structural, morphological and electrical properties have been investigated. X-ray diffraction analysis showed that the as-deposited as well as the annealed films were well crystallized and polycrystalline with cubic structure having (110) preferred orientation. AFM analysis showed uniform surface morphology with very low surface roughness values. The electrical parameters like the resistivity values are found decreasing and the mobility and carrier concentration values are observed to increase with annealing temperature. Sensor studies on SnO2 – TiO2 films annealed at 300o C showed very good response to methanol gas.