Aviad Shapira

VR-based planning of construction site activities

Abstract This paper presents an approach to the integration of site-related activities into the planning and scheduling of the entire construction project. The paper starts by briefly reviewing some common methods used by construction firms in the planning and scheduling of site activities. Next follows a discussion of current research efforts concerned with the modelling of site-related procedures. Then a virtual-reality-based model is proposed, which uses both knowledge-based simulation of the work progress and visualisation capabilities, to achieve the desired integration. Finally the prototype system is described and its potential is demonstrated through several examples.

The multiplicity concept in construction project planning

Why plan? Who should plan? What and when should one plan? These fundamental issues of construction planning raised by the authors 5 years ago, are revisited in this paper in the light of studies conducted recently within the construction industry. In the focus of this research program stood mature companies, advanced projects and competent and experienced practitioners of construction planning and management. The findings show that there is no one single answer to any of these basic questions and that in fact a state of multiplicity – of roles and users, plans and formats, timings and time horizons, planning parties and modes of preparation – prevail, calling upon the willing practitioner to resort systematically to situational analysis if effective planning is to be accomplished.

Stabilizing Production Flow of Interior and Finishing Works with Reentrant Flow in Building Construction

AbstractInterior and finishing activities in building construction exhibit high degrees of variation as a result of uncertainty in supply chains, variations in work quantities, client changes, and lack of predictability of the production capacity of subcontracting trades. Decisions must constantly be made concerning effective utilization of available resources. Reentrant workflow patterns, where a trade crew returns multiple times to the same space, make production control particularly difficult. We present a method for pull flow control at the operational level through real-time prioritization of pending work packages and daily regulation of crew assignments and trades’ production capacities. Application of various heuristics was evaluated using discrete-event simulation of a representative construction project. The experimental results emphasize the importance of dynamic control of allocation of production resources to those mature activities that ensure subsequent (downstream) flow. The most successful...

Evolution of involvement and effort in construction planning throughout project life

Abstract The paper provides answers to some key questions regarding the process of construction planning. The answers are based on a field study of present-day practice in US companies known to have adopted an advanced planning culture. The study focused on two planning measures, the involvement of various parties in planning and the relative effort invested in various planning areas, and examined their evolution throughout project life. Together with the findings and conclusions of the study, several implications for practitioners and academics are offered.

Three-Dimensional Fiber-Reinforced Plastic Grating Cagesfor Concrete Beams: A Pilot Study

An experimental and analytical study was conducted to investigate the feasibility of developing three-dimensional fiber-reinforced plastic (FRP) grating cages to reinforce concrete members. Experimental FRP cages, fabricated from off-the-shelf commercially manufactured pultruded FRP profiles, were used to reinforce three concrete beams which were tested to failure. The performance of the FRP grating cage reinforced beams was compared with that of a control beam reinforced with conventional steel rebars. The results of the testing are given and a detailed analysis of the failure modes of the FRP reinforced beams is provided. A simplified analytical model is proposed to calculate the failure load of the beams. A truss model is used to predict deflection at failure. Predictions of the proposed models agree well with the experimental data. The construction practice potential of using the FRP grating cages is discussed. The pilot study indicates that the future development of FRP grating cages for concrete reinforcement would appear to be warranted.

Achieving Construction Innovation through Academia-Industry Cooperation—Keys to Success

The conception, development, implementation, and commercialization of a crane-mounted vision system through close academia-industry cooperation illustrate how such joint efforts can yield research and development success. The vision system was devised to help solve the problem of blind lifts and other viewing concerns related to the operation of tower cranes on construction sites, thereby enhancing safety and productivity and saving money. In addition to other expected difficulties, the project faced the traditional skepticism of a conservative industry reluctant to adopt changes. The paper relays the chronology of the project and analyzes, stage by stage, the steps taken by the university-based developers to work in harmony with construction companies in particular, and with the industry at large, to ensure success. Lessons drawn from this experience are offered to future academician developers in the field of construction technology.

Combining Analytical Hierarchy Process and Agglomerative Hierarchical Clustering in Search of Expert Consensus in Green Corridors Development Management

Environmental management and planning are instrumental in resolving conflicts arising between societal needs for economic development on the one hand and for open green landscapes on the other hand. Allocating green corridors between fragmented core green areas may provide a partial solution to these conflicts. Decisions regarding green corridor development require the assessment of alternative allocations based on multiple criteria evaluations. Analytical Hierarchy Process provides a methodology for both a structured and consistent extraction of such evaluations and for the search for consensus among experts regarding weights assigned to the different criteria. Implementing this methodology using 15 Israeli experts—landscape architects, regional planners, and geographers—revealed inherent differences in expert opinions in this field beyond professional divisions. The use of Agglomerative Hierarchical Clustering allowed to identify clusters representing common decisions regarding criterion weights. Aggregating the evaluations of these clusters revealed an important dichotomy between a pragmatist approach that emphasizes the weight of statutory criteria and an ecological approach that emphasizes the role of the natural conditions in allocating green landscape corridors.

Selection of mobile cranes for building construction projects

The complicated process of selecting cranes for construction projects can be divided roughly into two main phases: (1) a general decision on the type of crane, mobile or tower; and (2) selection of the particular model according to the required size and technical specification. Several determinants of this second phase of the selection process in a typical mobile crane culture were investigated through on-site interviews with representatives of major construction companies. Factors affecting mobile crane selection were identified, classified, and rated according to their degree of influence. The involvement in equipment planning and crane selection was characterized with regard to project stages and planning parties. The findings were analysed with a view to the changing participation level of each party throughout project life. The conclusions of the study portray a picture that is different from the common assumptions about mobile crane selection, with respect to both influencing factors and the process itself. The study underlines the weight of non-project-specific factors, and shows that equipment planning is not merely a one-time technical exercise executed by a planner, but rather a process carried out throughout project life by a joint effort of several parties.

Safety by design: dialogues between designers and builders using virtual reality

Designers can contribute to enhancing the safety of construction work by considering how their decisions impact on both the physical environment in which construction workers operate and the means and methods they use. To do so, however, designers require knowledge about safety hazards on site and the opportunity to examine their designs early in projects. Through a set of studies virtual reality tools were used to examine the potential for collaborative dialogue between designers and builders to provide a forum for learning and proactive change of a design to make a project safer to build. In the tests, participants viewed proposed designs using virtual reality to examine various alternative design and construction scenarios. The study shows that consultation and dialogue with an experienced construction professional are highly beneficial for designers to appreciate the implications of designs on safety, and that designers are more willing to adapt design details than to change aesthetic aspects of their designs.

A workflow model for systems and interior finishing works in building construction

Modelling the flow of systems and interior finishing works in building construction has been hampered by the inability of traditional critical path modelling to reflect features of these works such as uncertainty, instability, non-linear and interrupted value-adding processes and re-entrant flow. Drawing on empirical data collected in a work study of a large residential project, a novel workflow model is proposed that explicitly models the flows of products and crews at a fine-grained level. The overall model includes a trade workflow model with a module for each work-package type, and a project level model in which multiple trade modules are embedded. The model was tested through implementation of a simulation of a prototypical construction project involving seven work-packages performed in a 20-storey residential tower with 120 customized apartments. The modelled flows of crews through the test building reflected the same behavioural features observed in construction projects. The model enables evaluation of the impact of management policies on production flow at different levels of detail. It is useful as a research tool and for future development of construction management software.