Construction materials constitute a major cost component in any construction project. The total cost of installed materials (or value of the materials) may be 50% or more of the total cost. Cost estimating is an assessment of the expected cost of any construction project. The accuracy of such an estimate has a serious effect on the expected profit of the construction contractor. Hence, a certain contingency premium should be added to the base estimate to increase the level of confidence. Such premium is materially affected by many factors. Through this research, the main factors that are expected to affect the accuracy of the construction materials' cost estimate were clearly identified. The numbers of these factors 46 were collected from the literature review. The twelve factors are identified as the most important factors. These factors were: Unsettlement of the local currency in relation to dollar value, fluctuation of price of raw materials, project materials monopoly by some suppliers, fraudulent activities of subcontractors, standard procedure for updating cost information, poor contractor experience for project type, improper planning and errors during construction, engaging in adequate skill on labor, waste control during material usage, location of project, improper construction methods and improper supervision at site and control.
A nonlinear strain compatibility model is considered to investigate the behavior of reinforced concrete deep beams. It is based on satisfying equilibrium of stresses and compatibility of strains at all layers of the beam cross-section. A VISUAL BASIC code is developed for this model. Strain distribution over the cross section depth in deep beams is different from shallow beams, and varies according to the case of loading, the span-to-depth ratio (L/h), and the structural system. The experimental values of strain over the cross-section depth for different cases for simply supported deep beams, are extracted from the available literature. Based on these values, simplified equations for strain profiles for each case is proposed to use them in the present model. A key feature of the model is the ability to illustrate the effect of shear deformation of the cross section. The model is validated by comparing predicted results with experimental ones from literature in terms of load-displacement.amounts of tension reinforcing steel are considered [3]. The stress and strain distribution along the deep beam depth are different from that in RC shallow beams.
Most of soil structure interaction methods for analyzing large-section supports such as barrette foundation modeling the barrette and surrounding soil using 3D FE model. In which, the model leads to a large finite element mesh of a large system of linear equations to be solved. In this paper, a Composed Coefficient Technique (CCT) is adapted for analyzing barrette. The technique takes into account the 3D full interactions between barrette and the surrounding soil. Due to the high rigidity of the barrette relative to the surrounding soil, a uniform or variable settlement along the barrette height can be considered. This enables to compose the stiffness coefficients of the soil matrix into composed coefficients, which consequently leads to a significant reduction in the soil stiffness matrix. An application for analyzing barrette by CCT is carried on the soil of the new area of East Port Said, in where the typical soil stratification is very week and structures in this area need to be supported by deep foundations such as barrettes. The application presents guidelines and diagrams for barrettes that may be used in East Port Said.
A flexibility-based reinforced concrete beam column element is developed to study the nonlinear static and dynamic response of reinforced concrete seismic resisting frames. To model beam to column flexible connections and rigid zones that formed from beam to column intersections, end springs and end offsets are included in the element formulation, respectively. The element flexibility matrix is formed by integration of in-span section flexibilities using conventional force relations using the Simpson's method. Each cross section in the element span is subdivided into concrete and steel fibers/layers with the assumption of linear strain distribution over the section depth. The effects of shear and bond slip are neglected in the element formulation. The formulated beam column element is implemented into a developed finite element program. For the sake of verification, a series of correlations studies against members and structures available in the literature subjected to either monotonic or cyclic loads were investigated and showed a good accuracy. The proposed element can be used in nonlinear static and dynamic analysis of seismic resisting systems.
Design of economic seismic resisting structural systems with an acceptable safety margin requires continuous improvements for the available numerical models and analysis tools. In this work, an improved reinforced concrete membrane element based on the modified compression filed theory (MCFT) is presented. The developed element is implemented into a developed finite element program in order to study seismic response of different types of seismic resisting systems which are commonly used in the construction of concrete buildings in Egypt. Two types of floor systems, (beamed/beamless floors) and two types of seismic resisting systems, (frames/coupled frames with shear walls), are investigated. Reinforced concrete flexibility-based beam column and plane stress elements were used to model frames and shear walls, respectively. The static response of these systems subjected to triangular load pattern was investigated through nonlinear static analysis. It was concluded that, the predicted force reduction factor based on nonlinear static analysis of the examined systems is 50% to 75% less than those provided by Egyptian code; such variation could lead to uneconomic or inadequate design.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.