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Volume 13 (1); March 25, 2023
Research Paper
Seismic Performance of Steel Moment Frame with Side-Plate Connections Combined with Friction Dampers
Omranifa T.
J. Civil Eng. Urban., 13(1): 01-09, 2023; pii:S225204302300001-13
DOI: https://dx.doi.org/10.54203/jceu.2023.1
Abstract
With the gradual change in the design method of structures from resistance-based methods to performance-based methods, existing common building frames do not respond to the criteria of these methods, and if these frames are designed with new performance criteria, the design will be uneconomical. The basic problem of the existing types of frames is the imbalance between hardness and plasticity in them. A structure must have sufficient hardness in order not to be displaced in an earthquake, and it must have high ductility in order to dissipate the energy of the earthquake well. In this article, the purpose of the structure's performance in the combination of friction dampers and side-pleat joints in the steel structure of the bending frame is according to the constraints in solving the problem such as architectural, executive and design limitations and considering the uncertainties inherent in the system. This problem is solved in such a way that all three conditions are estimated, and for this purpose, three structures, 6, 10, 15 stories, have been modeled in three dimensions and have been analyzed under time history analysis. In examining the arrangement of dampers in the frames, the amount of energy in the 3x3 structures in the second frame is more than the first frame, which has increased by about 15%. But in 5x5 structures, the amount of energy when the frame damper is 3 is more than other frames. In these structures, when the damper is in the third frame, the energy of the structure has increased by about 10% compared to other states. Also, the effect of side plate connection in increasing the hardness is also important. that the above connection will reduce displacement by creating hardness at the connection point, and as a result, it will absorb more energy.
Keywords: Friction damper - side plate connection - time history analysis
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Research Paper
Intercomparison of Rainfall Estimates of Three Distributions for Computation of PFD using Rational Formula and SUH Approach
Vivekanandan N, Srishailam C and Patil RG.
J. Civil Eng. Urban., 13(1): 10-17, 2023; pii:S225204302300002-13
DOI: https://dx.doi.org/10.54203/jceu.2023.2
Abstract
Peak flood discharge (PFD) for a given return period is considered as one of the most important parameters for planning and design of hydraulic structures, river protection works, and development of integrated water resources management projects. This can be achieved by adopting various methods such as flood frequency analysis, rational formula, envelope curves and Synthetic Unit Hydrograph (SUH) approach. Out of which, rational formula is applied for estimation of PFD for ungauged catchments with catchment area less than 25 km2 while SUH approach is adopted for ungauged catchments with catchment area more than 25 km2. This paper aims to investigate the study on intercomparison of probability distributions for estimation of extreme (i.e., 1-day maximum) rainfall for computation of PFD by adopting rational formula and SUH approach for the Vadhavan Port Project (VPP). The annual 1-day maximum rainfall series is extracted from the daily rainfall data observed at Dahanu site during the period 1969 to 2019 and also used for estimation of rainfall. The probability distributions viz., Extreme Value Type-1, 2-parameter Log Normal and Log Pearson Type-3 (LP3) adopted in extreme value analysis of rainfall is evaluated through diagnostic test using root mean square error and accordingly LP3 is adjudged as the best fit for estimation of rainfall. The 1-day maximum rainfall obtained from LP3 is considered to compute the rainfall intensity by applying one-third rule of IMD (India Meteorological Department) and also used for computation of PFD through rational formula. In SUH approach, the areal rainfall, physiographic and SUH parameters of the ungauged catchments are considered for computation of PFD. The study suggests the 25-year, 50-year and 100-year return period PFDs at six locations within the study area using rational formula and SUH approach could be considered for design purposes while designing any civil and hydraulic structures in the VPP.
Keywords:Log Pearson Type-3, Mean Square Error, Rainfall, Rational Formula, Synthetic Unit Hydrograph, Peak Flood Discharge
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Research Paper
Assessment of Drought Characteristics and Trend Analysis in Antalya Basin, Turkey
Mahnamfar F and Nigussie TA.
J. Civil Eng. Urban., 13(1): 18-24, 2023; pii:S225204302300003-13
DOI: https://dx.doi.org/10.54203/jceu.2023.3
Abstract
Drought is a phenomenon related to water scarcity due to decrease in precipitation over a long period of time. It is also identified as a natural and a recurrent feature of climate, although many erroneously consider it as a rare and random event. The understanding and trend analysis of historical drought is vital for the future development and management of water resources. In this study, the Standardized Precipitation Index (SPI) at SPI 1, 3, 6 and 12 month time scales was computed using long time series (1970-2007) of monthly precipitation data observed at 9 meteorological stations in Antalya Basin, Turkey. The computed SPI values were, then, subjected to the Mann-Kendall (MK) and Spearman’s Rho (SR) statistical trend analyses. Based on the results of the study, most of the results of SPI determined for above indicated time-scales, were found to fall under “No Drought” and “Near Normal” drought intensity classes. Though there are variations in the values of the drought characteristics considered in the study, the values did not show spatial pattern. In addition, significant trend without spatial pattern was observed in the SPI 12 values determined for almost all of the stations considered in the study.
Keywords: Drought; SPI; Drought duration; Drought magnitude; Antalya basin
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This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0)