Sahil Garg

The need to avoid rework or rectification, even before a facility is put into operation, cannot be overemphasized. Rework can be studied from two points of view: (1) its root causes, focusing on individual managerial issues such as worker training, coordination issues, and so forth; and (2) its distribution in the various components of the facility being constructed. Although the former has been studied quite extensively, little information is available about the latter. Addressing this gap and concentrating on building construction, this study presents the relative ranking of and the correlation among four activity-specific causes of rework, namely rework arising due to inappropriate concreting, reinforcement placement, shuttering, and scaffolding in five components of reinforced cement concrete construction in buildings, i.e., beams and slabs, columns, walls, staircases, and footings. The analysis was based on responses from more than 100 professionals and the use of statistical tools like relative importance index, the margin of error, ANOVA, Spearman’s coefficient of correlation, and structural equation modeling. It was found that whereas columns are the most critical components for rework for inappropriate concreting, beams and slabs were identified as the most critical component for rework due to inappropriate reinforcement placement, inappropriate formwork placement, and scaffolding work. Furthermore, the correlation studies exhibited poor correlation among the different building components and different activity-specific causes of rework, which implies that stakeholders need to develop activity-specific strategies for every component to reduce rework. In the future, the conclusions obtained from the study can be verified by recording and analyzing the events of rework in building construction projects.

This paper describes the efforts made in rectifying a large prestressed, L-shaped, vertical reaction wall with circular cavities and the lessons learnt. The wall was to be constructed with a certain flatness requirement, which it later turned out was not met. Though various studies have been undertaken in the past describing rectification of horizontal concrete floors, the present study discusses a novel approach to determine the extent of non-compliance and then re-surfacing of the vertical wall to achieve required flatness. The paper discusses in detail the applicability of various instruments like profilometers, water level manometers, and laser-based tools in determining the extent of undulations. It was found that the rotating laser-based tool best served the purpose for defect identification and that placing a layer of micro concrete along with a bonding agent using a novel construction method helped to achieve the desired level of flatness.

Purpose: Though the components and concepts of cost of quality (COQ) are well understood in the domain of manufacturing, only limited data are available from the construction industry for various reasons. The present study seeks to establish a relationship between project defect score (pds), representing the quality of construction in the project, and the COQ in the building construction industry. The study also seeks to estimate the contributions of the various components to the overall COQ in the construction industry, along with their distribution and interrelationships among themselves.Design/methodology/approach: A framework for estimating COQ was developed, and the data regarding prevention, appraisal and failure cost were collected from 122 projects. Various mathematical and statistical tools like Pearson's correlation, multiple linear regression (MLR) and curve fitting have been used for data analysis.Findings: The prevention–appraisal–failure (PAF) model was found to be appropriate to estimate COQ, and the prevention, appraisal, conformance cost (CC) and failure cost were found to vary between 0.19 and 8%, 0.05 and 5%, 0.3 and 10% and 0.01 and 5%, respectively, whereas the overall COQ varied from 3.5 to 10.01% of the project cost. The correlations between various components of COQ were found to be significant. MLR suggested that appraisal cost is more impactful in reducing failure cost than prevention cost. Using curve fitting, the cubic model appropriately represented all interrelationships. The optimal overall COQ was found to be 3.86%, and the reasons for low COQ have been explored.Originality/value: The study evaluates the applicability of available models for COQ calculations for the construction industry and presents a framework to estimate its components. The study also explores the interrelationship between the various components of COQ and presents a generalized relationship between COQ and the pds.

Variations in the design requirements of prestressed concrete girders lead to variations in their geometry and section profile, thereby influencing the characteristics of the waves which form the working principles of the various NDT techniques, and thus possibly shield the presence of air void. Thus, an experimental plan was adopted to study the effect of the changes in parameters like the cover to the duct, the material of the duct, the number of strands, and diameter of the duct on the efficiency of Ultrasonic Pulse Velocity (UPV), Ground Penetrating Radar (GPR) and Infrared Thermography (IRT) (active and passive) to detect a simulated void in a grouted duct. Seven 150 × 150 x 750 mm specimens were prepared with duct embedded in concrete. Both steel (inner diameter 106.6 mm) and plastic (inner diameter 105 mm and 86 mm) ducts were used. Three specimens had 3 strands, three specimens had 5 strands, and one specimen had 8 strands. It was found that the efficiency of GPR increased with the increase in the number of strands and duct diameter. Active IRT is highly efficient for the detection of voids than Passive Thermography. The presence of steel strands influenced UPV results.