Construction Practices Contributing to Rising Damp in Kumasi Metropolitan and Ejisu Municipal Assemblies in Ghana

Buildings represent significant investment of developers and, as such, it is important to ensure value for the capital injected into the construction of buildings. Unfortunately, due to neglect of proper construction practices, buildings are facing defects, and one of such defects is rising damp. This study sought to identify some of the construction practices contributing to rising damp in buildings and their effects and suggest some remedial measures for controlling and treatment of rising damps. Snowball sampling and purposive sampling techniques were used to gather data from a cross section of 78 building environment professionals in Kumasi and Ejisu who have experienced the effects of moisture rise. Relative Importance Index was used to rank the significance of the causes. The study revealed that failure to use damp-proof membrane or course, presence of groundwater, porosity of masonry, and concrete element sand flooding were the main causes of rising damp. Undersetting and saw slotting, making good plumbing leakages, using approved waterproof chemical injection, and application of admixtures were the main measures recommended to avert rising damp.

Multilevel Safety Intervention Implementation Strategies for Nigeria Construction Industry

This study was aimed at examining the relationships between the effectiveness of safety intervention programmes and implementation strategies in the Nigeria construction industry. Structured questionnaires were distributed to construction stakeholders across some selected states in Nigeria and the data generated were analysed using Pearson’s product moment correlation. The study found that the effectiveness of safety intervention programmes for construction site accidents prevention is significantly related to the communication implementation strategies. Based on the principles of social ecological theory and UNICEF’s communication for development strategies, this study developed a multilevel safety intervention implementation strategy for construction industries in Nigeria. Four communication strategies, namely, advocacy, social mobilisation, social change communication, and behaviour change communication, which are central to the effectiveness of safety intervention implementation programmes for construction site accidents prevention, were identified. It further revealed that these communication strategies could be individually and collectively applied at different intervention levels but that the greatest effect would be felt when all strategies are systematically combined with more efficient use of resources. The study recommended systematic actions by policy makers, construction organisations, and various community groups towards construction safety interventions, since maximum effect could only be felt when safety interventions are implemented across all levels.

A Study on the Dynamic Interaction between Three-Axle Vehicle and Continuous Girder Bridge with Consideration of Braking Effects

Continuous girder bridges become increasingly popular because of the rapid development of highway throughout the world. Most of previous researches on vibration analysis of a multispan continuous bridge subject to complex traffic loading and vehicle dynamic interaction focus on the girder displacement not considering braking effects. In current literature, few studies have discussed the effects of braking on continuous girder bridges. In this study, we employ the finite element method (FEM) to investigate the dynamic response of continuous girder bridge due to three-axle vehicle. Vertical reaction forces of axles that change with time make bending vibration of girder increase significantly. The braking in the first span is able to create response in other spans. In addition, the dynamic impact factors are investigated by both FEM and experiments on a real bridge structure. The results of this study extend the current understanding of the bridge dynamic behaviors and can be used as additional references for bridge codes by practicing engineers.

Estimating Concrete Workability Based on Slump Test with Least Squares Support Vector Regression

Concrete workability, quantified by concrete slump, is an important property of a concrete mixture. Concrete slump is generally known to affect the consistency, flowability, pumpability, compactibility, and harshness of a concrete mix. Hence, an accurate prediction of this property is a practical need of construction engineers. This research proposes a machine learning model for predicting concrete slump based on the Least Squares Support Vector Regression (LS-SVR). LS-SVR is employed to model the nonlinear mapping between the mix components and slump values. Since the learning process of the LS-SVR necessitates two hyperparameters, the regularization and the kernel parameters, the grid search method is employed search for the most desirable set of hyperparameters. Furthermore, to construct the hybrid model, this research collected a dataset including actual concrete slump tests from a hydroelectric dam construction project in Vietnam. Experimental results show that the proposed model is capable of predicting concrete slump accurately.

Risk Level Assessment in Construction Projects Using the Schedule Performance Index

Construction projects are risky in both physical implementation and management. The characteristics of the risk reinforce the necessity of efficient management to increase the chances of success without commitment to its goals. This study explores the correlation of delay and the schedule performance index (SPI) to evaluate the risk of a construction project completed with time overruns. The hypothesis that the SPI of projects with a delay is distinct from those projects without a delay is assumed. A database with 19 elements was used to test this hypothesis and to calculate limit values to the SPI. Therefore, the risk of delay will be small when the observed SPI is greater than the superior limit and large when the SPI is below the inferior limit. The simplicity involved in the calculation of these values showed an advantage in comparison with other methods of risk evaluation. Another strong point observed is that any company can determine the value of risk by considering its own history and support decisions like doing corrective actions.

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

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.

A Review on Mechanical and Hydraulic System Modeling of Excavator Manipulator System

A recent trend in the development of off-highway construction equipment, such as excavators, is to use a system model for model-based system design in a virtual environment. Also, control system design for advanced excavation systems, such as automatic excavators and hybrid excavators, requires system models in order to design and simulate the control systems. Therefore, modeling of an excavator is an important first step toward the development of advanced excavators. This paper reviews results of recent studies on the modeling of mechanical and hydraulic subsystems for the simulation, design, and control development of excavator systems. Kinematic and dynamic modeling efforts are reviewed first. Then, various approaches in the hydraulic system modeling are presented.

Maximizing Sustainability of Concrete through the Control of Moisture Rise and Drying Shrinkage Using Calcined Clay Pozzolan

The Ghanaian concrete industry is really a booming industry due to many infrastructural developments and the surge in residential development. However, many developmental projects that utilize concrete do suffer from the negative impact of moisture rise including paint peeling-off, bacterial and fungi growth, and microcracks as well as unpleasant looks on buildings. Such negative outlook resulting from the effects of moisture rise affects the longevity of concrete and hence makes concrete less sustainable. This study seeks to develop materials that could minimize the rise of moisture or ions through concrete medium. The experimental works performed in this study included pozzolanic strength activity index, water sorptivity, and shrinkage test. Calcined clay produced from clay was used as pozzolan to replace Portland cement at 20%. The strength activity test showed that the cement containing the calcined material attained higher strength activity indices than the control. The thermal gravimetric analysis showed that the pozzolan behaved partly as a filler material and partly as a pozzolanic material. The sorptivity results also showed that the blended mix resulted in lower sorptivity values than the control mortar. The study recommends that calcined clay and Portland cement mixtures could be used to produce durable concrete to maximize sustainability.

Management of Highway Projects in Egypt through Identifying Factors Influencing Quality Performance

While project management success focuses upon the processes and the successful accomplishments of cost and time objectives, product success deals with the quality of the final product. Recently, quality of the constructed highway has been considered highly important reason for the pavement response and its design life. The main objective of this paper is to improve the management of highway projects in Egypt by determining the most important factors influencing the quality performance of this industry. In total, 39 factors that may influence the quality of highway projects have been defined through a detailed literature review. The factors are tabulated in a questionnaire form, which is sent out to 13 owners of divided highways, 27 owners of regional roads, and 15 consultants. The analysis of the respondents’ perspectives using fuzzy triangle approach shows that the most important factors affecting the quality are availability of experienced staff in the owner’s and contractor’s teams during the project execution; efficiency of the owner’s inspection team; clarity of responsibilities and roles for each owner, consultant, and contractor; pavement which is not designed according to the regional conditions (e.g., soil type, temperature, and traffic volume); and asphalt quality and type used in the construction process.