Due to the inherent risks and increasing complexity of modern construction projects, delays and cost overruns have become common facts in the industry. Researchers and practitioners have used many techniques to assess project delays and apportion delay responsibility among the parties involved. Windows delay analysis has been recognized as one of the most credible techniques for analyzing construction delays. Despite its benefits, windows analysis can produce different results depending on the window size, it does not consider owner and contractor acceleration, it does not systematically consider the impact of several baseline updates made due to changes in the duration and logical relationships of the activities, and it does not consider the impact of the progress events on resource over-allocation and its consequent delays. This study proposes a computerized schedule analysis model that considers multiple baseline updates and resource over-allocation. The model uses a daily window size in order to consider all fluctuations in the critical path(s) and uses a legible representation of progress information to accurately apportion delays and accelerations among project parties. To facilitate its use, the model has been incorporated into a computer tool, EasyPlan, which integrates estimating, scheduling, resource management, and project control. A simple case study has been implemented on the proposed delay analysis model in order to demonstrate its accuracy and usefulness.

Due to the inherent risks and increasing complexity of modern construction projects, delays and cost overruns have become common facts in the industry. Researchers and practitioners have used many techniques to assess project delays and apportion delay responsibility among the parties involved. Windows delay analysis has been recognized as one of the most credible techniques for analyzing construction delays. Despite its benefits, windows analysis can produce different results depending on the window size, it does not consider owner and contractor acceleration, it does not systematically consider the impact of several baseline updates made due to changes in the duration and logical relationships of the activities, and it does not consider the impact of the progress events on resource over-allocation and its consequent delays. This study proposes a computerized schedule analysis model that considers multiple baseline updates and resource over-allocation. The model uses a daily window size in order to consider all fluctuations in the critical path(s) and uses a legible representation of progress information to accurately apportion delays and accelerations among project parties. To facilitate its use, the model has been incorporated into a computer tool, EasyPlan, which integrates estimating, scheduling, resource management, and project control. A simple case study has been implemented on the proposed delay analysis model in order to demonstrate its accuracy and usefulness.

Project managers today rely on scheduling tools based on the Critical Path Method (CPM) to determine the overall project duration and the activities’ float times. Such data provide important information about the degree of flexibility with respect to the project schedule as well as the critical and noncritical activities, which leads to greater efficiency in planning and control of projects. While CPM has been useful for scheduling construction projects, years of practice and research have highlighted a number of serious drawbacks that limit its use as a decision support tool. The traditional representation of CPM lacks the ability to clearly record and represent detailed as-built information such as slow/fast progress and complete representation of work interruptions caused by the various parties involved. In addition, CPM is based on two unrealistic assumptions: that the project deadline is not restricted and that resources are unlimited. With CPM, therefore, the most cost-effective corrective actions needed in order to recover delays and overruns cannot be determined. This research is based on the view that many of the drawbacks of CPM stem from the rough level of detail at which progress data is represented and analyzed, where activities’ durations are considered as continuous blocks of time. To overcome CPM drawbacks, this research presents a new Critical Path Segments (CPS) mechanism, with its mathematical formulation, that offers a finer level of granularity by decomposing the duration of each activity into separate time segments. The CPS mechanism addresses the problems with CPM in three innovative ways: (1) the duration of an activity is represented as a series of separate time segments; (2) the representation of the progress of an activity is enhanced; and (3) an optimization mechanism to incorporate project constraints into the CPS analysis. To demonstrate the ability of the CPS to provide better analysis than the traditional CPM, a number of case studies are used to show its ability to (1) simplify network relationships and accurately calculate floats and critical path(s); (2) achieve better resource allocation and facilitate accurate delay analysis; and (3) overcome problems associated with the use of multiple resource calendars. This research represents a change from well-known CPM techniques and has the potential to revolutionize and simplify the analysis of ongoing and as-built schedules. The developed CPS technique is expected to help project managers achieve a better level of control over projects and their corrective actions because it offers better visualization, optimization, and decision support for meeting project goals within the specified constraints.

Project managers today rely on scheduling tools based on the Critical Path Method (CPM) to determine the overall project duration and the activities’ float times. Such data provide important information about the degree of flexibility with respect to the project schedule as well as the critical and noncritical activities, which leads to greater efficiency in planning and control of projects. While CPM has been useful for scheduling construction projects, years of practice and research have highlighted a number of serious drawbacks that limit its use as a decision support tool. The traditional representation of CPM lacks the ability to clearly record and represent detailed as-built information such as slow/fast progress and complete representation of work interruptions caused by the various parties involved. In addition, CPM is based on two unrealistic assumptions: that the project deadline is not restricted and that resources are unlimited. With CPM, therefore, the most cost-effective corrective actions needed in order to recover delays and overruns cannot be determined. This research is based on the view that many of the drawbacks of CPM stem from the rough level of detail at which progress data is represented and analyzed, where activities’ durations are considered as continuous blocks of time. To overcome CPM drawbacks, this research presents a new Critical Path Segments (CPS) mechanism, with its mathematical formulation, that offers a finer level of granularity by decomposing the duration of each activity into separate time segments. The CPS mechanism addresses the problems with CPM in three innovative ways: (1) the duration of an activity is represented as a series of separate time segments; (2) the representation of the progress of an activity is enhanced; and (3) an optimization mechanism to incorporate project constraints into the CPS analysis. To demonstrate the ability of the CPS to provide better analysis than the traditional CPM, a number of case studies are used to show its ability to (1) simplify network relationships and accurately calculate floats and critical path(s); (2) achieve better resource allocation and facilitate accurate delay analysis; and (3) overcome problems associated with the use of multiple resource calendars. This research represents a change from well-known CPM techniques and has the potential to revolutionize and simplify the analysis of ongoing and as-built schedules. The developed CPS technique is expected to help project managers achieve a better level of control over projects and their corrective actions because it offers better visualization, optimization, and decision support for meeting project goals within the specified constraints.

Esta Tesis doctoral representa una nueva formulación del problema del GRCPSP (Generalized Resource-Constrained Project Scheduling Problem) mediante grafos PDM (Precedence Diagramming Method) con fragmentación en entornos realistas, donde las tareas son diferenciadas entre productivas y no productivas y las dependencias entre ellas no se limitan a los ya clásicos valores de dependencia, sino que se incorpora un nuevo concepto de relación de producción, apareciendo relaciones basadas en un cierto nivel de producción necesario de otra tarea para poder comenzar, o cierta producción que quedará pendiente de finalizar una vez finalizada la tarea precedente. Este nuevo enfoque del problema basado en procesos productivos, no solo elimina las paradojas causadas por las tareas críticas inversas o críticas perversas, sino que nos permite aplicar conceptos tradicionales de la planificación de la producción como es la productividad variable ocasionada por el aprendizaje con las repercusiones que esto produce en las relaciones basadas en producción. Además se analizan las naturalezas de los recursos intervinientes en el proyecto, reformulando los costes asociados a los mismos y su repercusión sobre el nuevo modelo propuesto, permitiendo la aplicación de algoritmos de optimización TCTP (Time Cost Trade-Off Problem) que hasta ahora era inviable. Para finalizar se incorpora la borrosidad a los valores intervinientes en el proyecto presentando la formulación de un modelo robusto de planificación de la producción basada en grafos PDM que sirve de punto de partida a la resolución del GRCPSP en entornos realistas. / Ponz Tienda, JL. (2010). GRCPSP Robusto basado en Producción para Proyectos de Edificación y Construcción [Tesis doctoral]. Editorial Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/8540 / Palancia

[pt] A necessidade de aumentar a produtividade no setor da construção civil estimulou investimentos em soluções digitais e a incorporação de princípios de manufatura na cadeia construtiva. A implementação de elementos estruturais padronizados fabricados fora do canteiro de obra é considerada uma prática válida para atingir este objetivo. O projeto para fabricação e montagem é um conceito que envolve diretrizes a serem consideradas no desenvolvimento do projeto, cuja finalidade é facilitar a fabricação e montagem de componentes. A metodologia BIM pode incorporar análises de planejamento e construtibilidade para apoiar a tomada de decisão no contexto de construções replicáveis em escala de concreto armado. A presente investigação inclui uma revisão sistemática da literatura que orientou a pesquisa. Com base na SLR (Structured Literature Review), foi desenvolvido um Manual de Entrega de Informações que propõe um novo fluxo de trabalho no qual os estudos de planejamento construtivo e princípios de fabricação e montagem são agregados nos estágios iniciais do projeto para aproveitar a colaboração intrínseca da metodologia BIM. Para ilustrar o fluxo de trabalho proposto no IDM (Information Delivery Manual) desenvolvido é apresentado um experimento de um complexo de escolas. As informações do modelo parametrizado serviram como dados de entrada para as análises realizadas permitindo assim que pudessem ser comtemplados diferentes cenários de soluções estruturais. Os resultados obtidos pelo experimento indicam que a consideração de elementos de concreto pré-fabricado nem sempre vai contra os interesses econômicos, práticos e estéticos. Por fim, as análises de planejamento e construtibilidade são parâmetros importantes nas tomadas de decisão para aprimorar a identificação de oportunidades de melhorias no projeto e potencializar a eficiência de trabalho no canteiro de obra. / [en] The need to increase the civil construction sector stimulates investments in digital solutions and manufacturing principles in construction industry. The employment of standardized structural elements manufactured off-site construction, such as structural precast element, is considered a valid practice to achieve this purpose. The Design for Manufacturing and Assembly (DFMA) is a concept that involves guidelines considered in the development of the project and has the objective to facilitate the manufacturing and assembly of a product or component. Building Information Modeling (BIM) methodology can incorporate planning and constructability analysis to support decision making in the context of scalable and replicable concrete building projects. The present investigation includes a Structured Literature Review (SLR) that guided the research. Based on the SLR, an Information Delivery Manual (IDM) was developed to propose a new workflow in which the studies of construction planning and the application of manufacturing and assembly principles are considered in the early stages of design to take advantage of the collaboration intrinsic to the BIM methodology. An experiment of a school complex is presented to illustrate the workflow proposed in the developed IDM. The parametric model information was the key input to run analyzes in different structural solutions scenarios. The results indicated that the consideration of precast concrete elements does not always contradict economic, practical and aesthetic interests. Finally, planning and constructability analyzes are important parameters in decision-making, enhancing the recognition of opportunities for improvement in the project and increasing the efficiency of work in the construction site.