scholarly journals Cost Analysis of Precast and Cast-in-Place Concrete Construction for Selected Public Buildings in Ghana

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Richard Oduro Asamoah ◽  
John Solomon Ankrah ◽  
Kofi Offei-Nyako ◽  
Ernest Osei Tutu
Keyword(s):  
Construction Industry ◽  
Life Cycle Cost ◽  
Precast Concrete ◽  
Concrete Columns ◽  
Concrete Slabs ◽  
Effective Management ◽  
Cost Estimating ◽  
Concrete Technology ◽  
Structural Frame ◽  
Concrete Elements

The construction industry in Ghana is becoming efficient in the area of cost and achieving advance technologies. The effective management of cost enables clients, developers, and facilitators to achieve value for money. Concrete is a major component in every construction project. The use of precast concrete technology has been embraced by the construction industry in Ghana. This study seeks to analyze cost estimating of the structural frame (column and slab) by considering cast-in-place and precast concrete slabs and columns, respectively. Relative importance and Kendall’s concordance agreement were used to determine the rankings and agreement of advantages of using precast concrete. The study established that precast concrete slabs were on average 23.22% cheaper than the cast-in-place concrete elements and precast columns were averagely 21.4% less than cast-in-place concrete columns. The study established that professionals prefer the use of precast concrete products because of the life cycle cost.

Structural grouting of load-bearing precast concrete elements: Issues and solutions

PCI Journal ◽  
2022 ◽  
Vol 67 (1) ◽  
Author(s):  
Keyword(s):  
Construction Industry ◽  
Precast Concrete ◽  
Concrete Columns ◽  
The United States ◽  
Poor Quality ◽  
Building Codes ◽  
Concrete Walls ◽  
Load Bearing ◽  
Concrete Elements

The purpose of this paper is to raise construction industry awareness regarding structural grouting of precast concrete projects in the United States. Incidents related to structural grouting have occurred with both precast concrete systems and other building systems. Designers, architects, owners, insurance carriers, and the construction industry in general are becoming increasingly aware of deficient grouting installation methods and verification procedures. Concerns include the timeliness of grout installation during the erection process, the lack of grout on some components of finished projects, and the poor quality of installed grout. These concerns pertain to horizontal connection joints of critical load-bearing elements between foundations and precast concrete columns and walls, stacked precast concrete columns, and stacked precast concrete walls. Current building codes and standards provide no requirements and limited guidance for the installation or special inspection of these critical horizontal joints. In an effort to address this gap in building codes and standards, as it specifically relates to precast concrete structural products, some precast concrete producers and erectors are implementing several strategies and new procedures, as noted and further developed in this paper.

scholarly journals Optimization of reinforcing steel with genetic algorithms for the design of concrete columns

2021 ◽  
Author(s):  
Luis Fernando Verduzco
Keyword(s):  
Construction Industry ◽  
Cross Sections ◽  
Optimization Algorithm ◽  
Structural Engineering ◽  
Heuristic Algorithms ◽  
Concrete Columns ◽  
Reinforcing Steel ◽  
Structural Elements ◽  
Optimization Program ◽  
Concrete Elements

Is presented hereby the creation of an optimization program for the design of reinforcing steel for any type of structural elements which may be considered as columns, pillar, pilots or dies, subjected to flexo-compression mechanic stresses for rectangular cross sections elements with the support of numeric methods and meta-heuristic algorithms for the optimization of constructions costs, particularly the Genetic algorithm, adapting such algorithms to the optimization problem so that it makes the resultant designs practical and convenient for its application in the construction industry, based on certain criteria from NTC-17 and questioning other. It will be shown how such optimization algorithm was adapted to the problem, as well as other general numeric methods for engineering and others developed specifically for structural engineering for the optimal design of this sort of concrete elements. Moreover, sensibility cost analysis of unitary construction prices are presented as well, with which the objective function for the optimization algorithm was created. At the end, results of various experiments with and without the optimization program are shown, making comparisons between different structural models regarding cost and geometry.

SETTING A DIAGRAM APPROACH TO CALCULATING VIBRATED, CENTRIFUGED AND VIBROCENTRIFUGED REINFORCED CONCRETE COLUMNS WITH A VARIATROPIC STRUCTURE

2020 ◽  
pp. 22-34
Author(s):  
Л. Р. Маилян ◽  
С. А. Стельмах ◽  
Е. М. Щербань ◽  
М. П. Нажуев
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cross Section ◽  
Concrete Columns ◽  
Reinforced Concrete Columns ◽  
The Cross ◽  
Concrete Elements ◽  
Diagram Approach

Состояние проблемы. Железобетонные элементы изготавливаются, как правило, по трем основным технологиям - вибрированием, центрифугированием и виброцентрифугированием. Однако все основные расчетные зависимости для определения их несущей способности выведены, исходя из основного постулата - постоянства и равенства характеристик бетона по сечению, что реализуется лишь в вибрированных колоннах. Результаты. В рамках диаграммного подхода предложены итерационный, приближенный и упрощенный способы расчета несущей способности железобетонных вибрированных, центрифугированных и виброцентрифугированных колонн. Выводы. Расчет по диаграммному подходу показал существенно более подходящую сходимость с опытными данными, чем расчет по методике норм, а также дал лучшие результаты при использовании дифференциальных характеристик бетона, чем при использовании интегральных и, тем более, нормативных характеристик бетона. Statement of the problem. Reinforced concrete elements are typically manufactured according to three basic technologies - vibration, centrifugation and vibrocentrifugation. However, all the basic calculated dependencies for determining their bearing capacity were derived using the main postulate, i.e., the constancy and equality of the characteristics of concrete over the cross section, which is implemented only in vibrated columns. Results. Within the framework of the diagrammatic approach, iterative, approximate and simplified methods of calculating the bearing capacity of reinforced concrete vibrated, centrifuged and vibrocentrifuged columns are proposed. Conclusions. The calculation according to the diagrammatic approach showed a significantly better convergence with the experimental data than that using the method of norms, and also performs better when using differential characteristics of concrete than when employing integral and particularly standard characteristics of concrete.

Chromate and amine contact allergies in workers manufacturing precast concrete elements

2016 ◽  
Vol 75 (6) ◽  
pp. 363-369 ◽  
Author(s):  
Martin Mowitz ◽  
Erik Zimerson ◽  
Inese Hauksson ◽  
Ann Pontén
Keyword(s):  
Precast Concrete ◽  
Concrete Elements

Non-Destructive Identification of Defects in Power Support Structure Foundations by Means of Acoustic Techniques

2014 ◽  
Vol 606 ◽  
pp. 95-98
Author(s):  
Lukasz Sadowski
Keyword(s):  
Construction Industry ◽  
Support Structure ◽  
Air Voids ◽  
Impact Echo ◽  
Acoustic Techniques ◽  
Location Depth ◽  
Concrete Elements ◽  
Non Destructive ◽  
Made In

Prefabricated power support structure foundations are made in prefabrication plants where concrete is laid in layers in moulds. The quality of the prefabricated units depends mainly on proper concrete mixture compaction, which is usually effected by means of immersion vibrators. It happens that when the vibrator is withdrawn too quickly, defects, in the form of, e.g., air voids and zones of insufficiently vibrated concrete, appear. Modern non-destructive acoustic techniques, which in recent years have been increasingly commonly used in the construction industry, are highly suitable for testing concrete elements, particularly prefabricated concrete units. The non-destructive impact-echo technique is particularly useful for determining defect location depth and for locating defective areas.

Effects of the award of public service contracts on the performance and payroll of winning firms

2021 ◽  
Author(s):  
Diego Ravenda ◽  
Maika Melina Valencia-Silva ◽  
Josep Maria Argiles-Bosch ◽  
Josep García-Blandón
Keyword(s):  
Construction Industry ◽  
Public Service ◽  
Social Goals ◽  
Effective Management ◽  
Difference In Differences ◽  
Positive Effects ◽  
Service Contracts ◽  
Performance Dimensions ◽  
Service Procurement ◽  
Medium Firms

Abstract We investigate the effects of an exogenous demand shock arising from the award of public service contracts by Italian public administrations in 2015 on a sample of 1782 winning small and medium firms that were not awarded any contract during the previous 3 years. Using a difference-in-differences model with continuous treatments estimated on a propensity score matched sample, our results reveal that higher awarded values enhance various performance dimensions of the winning firms as well as their average payroll per employee. Nonetheless, higher winning rebates moderate the positive effects of the award on payroll by inducing the winning firms to downward manage both salaries and social security contributions per employee to maintain their desired level of performance. The effects are mostly significant for smaller microenterprises. In addition, winning rebates negatively affect the performance of firms in the construction industry by leading these firms to downward manage the payroll of their employees more aggressively than firms in other industries. Our findings provide novel insights for the implementation of industrial policies aimed at achieving sustainable macroeconomic and social goals, within the business fabric, through the effective management of public service procurement.

scholarly journals Modified mortar pad behavior in the transfer of compressive stresses

2016 ◽  
Vol 9 (3) ◽  
pp. 414-434
Author(s):  
J. D. Ditz ◽  
M. K. EL Debs ◽  
G. H. Siqueira
Keyword(s):  
Precast Concrete ◽  
Concrete Strength ◽  
Compressive Load ◽  
Stress Transfer ◽  
Compressive Stresses ◽  
Bonded Phase ◽  
Concrete Blocks ◽  
Load Tests ◽  
Styrene Butadiene ◽  
Concrete Elements

ABSTRACT This research aims to analyze the compressive stress transfer between precast concrete elements using cement mortar pads modified with polypropylene fibers, styrene-butadiene latex and heat-expanded vermiculite. The stress transfer analyses are performed interleaving a cementbearing pad between two concrete blocks, subjecting the entire specimen to different compressive load tests. The parameters analyzed in the tests are: surface roughness (using bosses on the bonded phase of different thicknesses), compressive strength with monotonic and cyclic loadings. The main results obtained in this study are: a) the presence of pad increased the strength in 24% for thicknesses of imperfections of 0.5 mm and approximately 12% for smooth faces blocks; b) gain of effectiveness of the bearing pad when the concrete strength was reduced; c) for cyclic loading, the bearing pad increased in 48% the connections strength.

Sign in / Sign up

Export Citation Format

Share Document