Modelling the boundaries of project fast-tracking

Fast-tracking a project involves carrying out sequential activities in parallel, partially overriding their original order of precedence, to reduce the overall project duration. The current predominant mathematical models of fast-tracking are based on the concepts of activity sensitivity, evolution, dependency and, sometimes, information exchange uncertainty, and aim to determine optimum activity overlaps. However, these models require some subjective inputs from the scheduler and most of them neglect the merge event bias. In this paper, a stochastic model for schedule fast-tracking is proposed. Relevant findings highlight the existence of a pseudo-physical barrier that suggests that the possibility of shortening a schedule by more than a quarter of its original duration is highly unlikely. The explicit non-linear relationship between cost and overlap has also been quantified for the first time. Finally, manual calculations using the new model are compared with results from a Genetic Algorithm through a case study

Estimating the number of new and repeated bidders in construction auctions

The number of new bidders – bidders from whom there is no previous registered participation – is an important variable in most bid tender forecasting models, since the unknown competitive profile of the former strongly limits the predictive accuracy of the latter. Analogously, when a bidder considers entering a bid or when an auctioneer is handling a procurement auction, assessing the likely proportion of experienced bidders is considered an important aspect, as some strategic decisions or even the awarding criteria might differ. However, estimating the number of bidders in a future auction that have not submitted a single bid yet is difficult, since there is no data at all linking their potential participation, an essential requirement for the implementation of any forecasting or estimation method. A practical approach is derived for determining the expected proportion of new bidders to frequent bidders as a function of the population of potential bidders. A multinomial model useful for selective and open tendering is proposed and its performance is validated with a dataset of actual construction auctions. Final remarks concern the valuable information provided by the model to an enduring unsolved bidding problem and the prospects for new research continuations

Human resource allocation to multiple projects based on members’ expertise, group heterogeneity and social cohesion

Project managers regularly allocate human resources to construction projects. This critical task is usually executed by fulfilling the minimum project staffing requirements normally based around the quantity and competence of project members. However, research has shown that team performance can increase by up to 10% and 18%, respectively, as a consequence of the group members’ heterogeneity and social cohesion. Also, there is currently no practical quantitative tool which incorporates these aspects to allow project managers to achieve this task efficiently and objectively. A new quantitative model for the effective allocation of human resources to multiple projects, which takes into account group heterogeneity and social cohesion is proposed. This model is easy to build, update and use in real project environments with the use of a spreadsheet and a basic optimization engine (e.g. Excel Solver). A case study is proposed and solved with a Genetic Algorithm to illustrate the model implementation. Finally, a validation example is provided to exemplify how group heterogeneity and social cohesion condition academic achievement in an academic setting

M-PERT: manual project-duration estimation technique for teaching scheduling basics

The Program Evaluation and Review Technique (PERT) has become a classic Project Management tool for estimating project duration when the activities have uncertain durations. However, despite its simplicity and widespread adoption, the original PERT, in neglecting the merge event bias, significantly underestimated the duration average and overestimated the duration variance of real-life projects. To avoid these and other shortcomings, many authors have worked over the last 60 years at producing interesting alternative PERT extensions. This paper proposes joining the most relevant of those to create a new reformulated PERT, named M-PERT. M-PERT is quite accurate when estimating real project duration, while also allowing for a number of interesting network modelling features the original PERT lacked: probabilistic alternative paths, activity self-loops, minima of activity sets and correlation between activities. However, unlike similar scheduling methods, M-PERT allows manual calculation through a recursive merging procedure that downsizes the network until the last standing activity represents the whole (or remaining) project duration. Hence, M-PERT constitutes an attractive tool for teaching scheduling basics to engineering students in a more intuitive way, with or without the assistance of computer-based simulations or software. One full case study will also be proposed and future research paths suggested

Factors affecting contractor's bidding success for international infrastructure projects in Australia

This paper examines the effects of different factors on the success or failure of bids for infrastructure projects in Australia. Logistic regression analysis was used to empirically determine which factors have the largest effect on bidding success. Data was collected from 123 bids submitted by several infrastructure companies with subsidiaries in Australia. The analysis found that having a competitive advantage and a local partner, and also not competing against a local company were the most important factors; as they significantly increase the chances of success. However, four other factors, having relevant expertise, resource availability, a previous relationship with the client, and a previous relationship with consortium members, are ‘essential’ to be able to compete; as the absence of any of these four factors results in bid failure, although having them is not a guarantee of success. Results of this paper provide valuable information for any company considering the opportunity of entering into Australia’s infrastructure market as well as for companies that are already present in that country and are considering whether to bid for a specific project

Aplicación de herramientas de la filosofía Lean Construction en el mejoramiento del borde costero de Constitución

225 p.Este trabajo trata principalmente de la aplicación de ciertas herramientas de la filosofía Lean Construction en una de las partidas del proyecto “Mejoramiento Borde Costero Constitución Sector Fluvial, Etapa I Comuna de Constitución, Región del Maule”, realizado por la Empresa Constructora Gonzalo Orellana e hijo Ltda.En este proyecto se elaboró una secuencia de aplicación donde primero se realizó la identificación de los principales problemas en las actividades, seguido de la identificación de las causas a estos problemas y, posteriormente, la elaboración de las soluciones. Además se escogió el muro de protección de la sección 4 como la partida ideal para aplicar las diferentes herramientas.Para identificar las pérdidas que se produjeron en la partida en estudio se utilizaron 3 herramientas, las cuales fueron analizadas por separado con el fin de estimar cuál era la más eficiente. Entre estas herramientas se encuentran la encuesta de pérdidas, el muestreo del trabajo y el Value Stream Mapping, las cuales permitieron identificar pérdidas por esperas, movimientos innecesarios, talento, sobreprocesamiento, etc.Posteriormente, para identificar las causas que produjeron estas pérdidas, se utilizaron 2 herramientas, las cuales fueron analizadas por separado con fin de seguir con el mismo propósito anterior. Estas herramientas fueron el diagrama de causa-efecto y los 5-Why, las cuales permitieron identificar causas por métodos de trabajo inadecuados, problemas de planificación, inapropiados sistemas de control, etc. Finalmente, para proponer varias soluciones, se utilizó nuevamente la herramienta Value Stream Mapping, en la cual se recomendaron ideas enfocadas en la utilización de otras herramientas del Lean Construction (Last Planner, Heijunka, Líneas de balance y TQM). Por último, en relación a los resultados obtenidos del estudio, con el objetivo de mejorar las productividad de las obras de construcción de la Empresa Constructora Gonzalo Orellana e hijo Ltda, se recomendó que se utilizaran las herramientas aplicadas y sugeridas en las soluciones con el fin de evaluar mejor sus métodos de trabajo, visualizar sus errores y reducir los principales problemas en sus proyectos

On competitive bidding: scoring and position probability graphs

Iso-score curves graph (iSCG) and mathematical relationships between Scoring Parameters (SP) and Forecasting Parameters (FP) can be used in Economic Scoring Formulas (ESF) used in tendering to distribute the score among bidders in the economic part of a proposal. Each contracting authority must set an ESF when publishing tender specifications and the strategy of each bidder will differ depending on the ESF selected and the weight of the overall proposal scoring. The various mathematical relationships and density distributions that describe the main SPs and FPs, and the representation of tendering data by means of iSCGs, enable the generation of two new types of graphs that can be very useful for bidders who want to be more competitive: the scoring and position probability graphs

Do projects really end late? On the shortcomings of the classical scheduling techniques

Many engineering projects fail to meet their planned completion dates in real practice. This is a recurrent topic in the project management literature, with poor planning and controlling practices frequently cited among the most significant causes of delays. Unfortunately, hardly any attention has been paid to the fact that the classical scheduling techniques—Gantt chart, Critical Path Method (CPM), and Program Evaluation and Review Technique (PERT)—may not be as fit for purpose as they seem. Arguably, because of their relative simplicity, these techniques are still almost the only ones taught nowadays in most introductory courses to scheduling in many engineering and management degrees. However, by utterly ignoring or inappropriately dealing with activity duration variability, these techniques provide optimistic completion dates, while suffering from other shortcomings. Through a series of simple case studies that can be developed with a few participants and common dice, a systematic critique of the classical scheduling techniques is offered. Discussion of the case studies results illustrate why limiting the contents of scheduling education and teaching can be detrimental, as the aforementioned classical scheduling techniques cannot not provide project managers with sufficient resources to effectively plan and control real projects

Mathematical relationships between scoring parameters in capped tendering

[EN] Mathematical relationships between Scoring Parameters can be used in Economic Scoring Formulas (ESF) in tendering to distribute the score among bidders in the economic part of a proposal.Each contracting authority must set an ESF when publishing tender specifications and the strategy of each bidder will differ depending on the ESF selected and the weight of the overall proposal scoring.This paper introduces the various mathematical relationships and density distributions that describe and inter-relate not only the main Scoring Parameters but the main Forecasting Parameters in any capped tender (those whose price is upper-limited).Forecasting Parameters, as variables that can be known in advance before the deadline of a tender is reached, together with Scoring Parameters constitute the basis of a future Bid Tender Forecasting Model. © 2012 Elsevier Ltd. APM and IPMA.Ballesteros Pérez, P.; González-Cruz, M.; Cañavate-Grimal, A. (2012). Mathematical relationships between scoring parameters in capped tendering. International Journal of Project Management. 30(7):850-862. https://doi.org/10.1016/j.ijproman.2012.01.008S85086230

Non-linear time-cost trade-off models of activity crashing: Application to construction scheduling and project compression with fast-tracking

[EN] When shortening a project's duration, activity crashing, fast-tracking and substitution are the three most commonly employed compression techniques. Crashing generally involves allocating extra resources to an activity with the intention of reducing its duration. To date, the activity time-cost relationship has for the most part been assumed to be linear, however, a few studies have suggested that this is not necessarily the case in practice. This paper proposes two non-linear theoretical models which assume either collaborative or non-collaborative resources. These models closely depict the two most common situations occurring during construction projects. The advantages of these models are that they allow for both discrete and continuous, as well as deterministic and stochastic configurations. Additionally, the quantity of resources required for crashing the activity can be quantified. Comparisons between the models and another recent fast-tracking model from the literature are discussed, and a Genetic Algorithm is implemented for a fictitious application example involving both compression techniques.This research was supported by the CIOB Bowen Jenkins Legacy Research Fund (reference BLJ2016/BJL.01) and by NERC under the Environmental Risks to Infrastructure Innovation Programme (reference NE/R008876/1) at the University of Reading.Ballesteros-Pérez, P.; Elamrousy, KM.; González-Cruz, M. (2019). Non-linear time-cost trade-off models of activity crashing: Application to construction scheduling and project compression with fast-tracking. Automation in Construction. 97:229-240. https://doi.org/10.1016/j.autcon.2018.11.0012292409