Author(s): Hussein M. Elsanadedy
Pages: 1-11 Paper ID:211001-4646-IJCEE-IJENS Published: February, 2021
Abstract:-- Due to discontinuity at beam-column joints, precast concrete structures are vulnerable to the potential of progressive collapse under the removal of one or more columns. Hence, efficient techniques are needed to strengthen existing precast beam-to-column connections for prohibiting (or diminishing) the risk of progressive collapse under column-removal event. This paper presents simplified analytical models for estimating the progressive collapse resistance of precast beam-column assemblies upgraded with a hybrid system having steel NSM (near-surface mounted) bars combined with FRP (fiber reinforced polymer) sheets. The developed models were validated with the help of available test data on half-scale 2D frame assemblies – comprising of three columns and two beams – tested under the loss of the middle column. Test assemblies included unstrengthened reference precast specimen, cast-in-situ concrete frame, and NSM/FRP-upgraded precast specimen. Parametric studies were also performed for assessing the influence of different variables on the progressive collapse capacity of retrofitted precast assembly in the event of column removal.
Keywords: Strengthening; FRP sheets; NSM bars; Progressive collapse; Precast beam-column connection; Column-removal scenario, Analytical models.
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Author(s): Abdul Hamid Payapo
Pages: 12-15 Paper ID:212301-9494-IJCEE-IJENS Published: February, 2021
Abstract:-- Road Preservation Project on the Sp. Dodinga - Sofifi - Akelmo - Payahe - Weda is a project that has a level of complexity that is quite complicated because all of the work consisting of Engineering, Procurement, and Construction is fully borne by the contractor or construction service company that works on it. The number of work items contained in a road preservation project causes risk factors or uncertainties. From the results of factor extraction by interpreting the loading factor of each variable item, namely latent Financial Variables (X1) 76.726%, Human Resources (X2) 77.310%, Materials (X3) 89.253%, Equipment (X4) 94,889, Work Implementation Methods (X5 ) 86.823%, Change in Design (X6) 71.435%, Work Environment (X7) 96.192%. The risks that have the most effect are according to the ranking order of each variable during the construction work of the Road Preservation Project, Sp. Dodinga - Sofifi - Akelamo - Payahe - Weda, North Maluku Province, are among others; Work Environment, namely the condition around the road (right and left) which is overgrown with wild plants, so that it looks like the road is not well maintained; Equipment, inadequate operator personnel in operating heavy equipment during work; Material, material scarcity (non-local) often occurs because it has to be imported from outside the region; Method of Execution of Work, Implementation of work is not in accordance with predetermined specifications; Human resources, human resources who work can not coordinate well and do not produce good road projects; Finance, Contractor's inadequate financial capacity and use of contract advances that are not used for the benefit of project implementation; Design Changes, Design Changes Often the owner design changes due to the use or function that changes from the initial planning when the work is being carried out.
Keywords: ---
Full Text (.pdf)  International Journals Of Engineering and Science | 119 KB
Author(s): Zakia SADAT, Abdussamet ARSLAN
Pages: 16-28 Paper ID:212201-4848-IJCEE-IJENS Published: February, 2021
Abstract:-- This paper aims to evaluate the possible improvement of the seismic performance of asymmetric-plan buildings. This goal is achieved by eliminates eccentricity between the centres of mass and rigidity and provides balanced rigidity in all directions, thus minimizing torsion. Structural optimization techniques should solve the problem to efficiently distribute materials throughout the structure to limit the eccentricity between the centres of mass and rigidity at each floor level of the building. This problem is considered as a sizing optimization problem. For this purpose, three structural models are selected to represent different structural system. These structural models are single storey shear buildings. The eccentricity optimization problem has been formulated and implemented using MATLAB by employing Genetic Algorithm (GA) which is computationally efficient in solving such types of optimization problems. The design variables are constituted by the columns and shear walls of the structure which located at each storey layout. The Turkish Earthquake Standard Code of practice TEC-2007 guidelines are used to analyze and designed buildings and as a constraint. The efficiency of the genetic algorithm was examined and found to be good. All the solved problems proved that the results are economical and give minimum eccentricity.
Keywords: Torsional balanced design, structural optimization, genetic algorithm
Full Text (.pdf)  International Journals Of Engineering and Science | 1018 KB