Civil & Environmental Engineering

Leading North American precast/prestressed concrete companies have invested major efforts and resources to spawn the development of intelligent parametric three-dimensional modeling software solutions for their industry. The executive decision to take this course of action was based on the expectation that the technology would provide benefits throughout the precast business process. Initial experience with prototype modeling systems is beginning to confirm earlier expectations regarding productivity gains and error reduction, although adoption of the systems is still in its early stages. This paper enumerates the various direct and indirect benefits that have been identified and assessed to date and provides a conservative set of benchmarks that can be applied as implementation takes place. Some of the benefits have also been evaluated in economic terms, based on current industry benchmarks of productivity and error rates. Based on these assessments, an example of a large precast company’s target evaluation of the economic benefit it expects to derive during the first four years of adoption is presented.

CHASTE—'Construction Hazard Assessment with Spatial and Temporal Exposure'—is a conceptual model that enables forecasting of safety risks in construction projects for different trades, at appropriate levels of detail and reliability for different planning windows and managerial purposes, in a highly automated fashion. Unlike earlier models, CHASTE explicitly accounts for the fact that construction workers are frequently endangered by activities performed by teams other than their own. The risks to which workers are exposed change through time, as the activities performed and the physical environment of construction sites change. CHASTE uses a knowledge base of construction activities and probabilities of loss-of-control events, coupled with a project's construction plan and a digital building model, to forecast risk levels for work teams. It has been implemented in prototype software and tested on two projects.

Buildings are complex products containing relatively large numbers of distinct parts that are collected in multiple assemblies for different design, analysis and production purposes. Modeling buildings in fully parametric 3D computer-aided design (CAD) systems offers numerous benefits in terms of productivity, the ability to rapidly generate design alternatives at different levels and elimination of errors that result from the disparity between different drawings in current practice. However, full realization of these benefits requires specialized functionality, including top-down modeling, objects with functional behavior, the ability to embed contextual design intent, automation of layout and detailing and appropriate management of similar objects. An effective system must provide such functionality while maintaining adequate response times. The requirements, features and performance have been examined as part of specification of a new 3D parametric CAD platform for the North American Precast Concrete Software Consortium (PCSC). They are described and discussed after a review of solid and parametric modeling, with examples from the domain of precast concrete construction.

Anew paradigm is presented in which designers,
contractors, and suppliers process project information,
which is stored in a central project model, by using
application routines provided on-line as object-oriented
methods instead of stand-alone applications. Commercial
project managementWeb site companies can provide
the service through application methods tightly coupled
with a project model. The development and use of such
“intelligent” object sets is exemplified by the use of intelligent
parametric templates (IPT) in three sample applications:
for RC slab design, formwork design, and labor
monitoring. The research requirements relating to the proposed paradigm are discussed, in light of the experience
gained in development of the IPTs. The paradigm offers
a technical and economic alternative to the development
of industry-wide building project models.

A new computer-based approach to the problem of design of reinforced concrete columns that may be subjected to biaxial bending is presented. Previous approaches to the design of concrete columns (including those with biaxial bending) using computers have been primarily based on iterative numerical analysis. The EIDOCC (Expert Interactive Design of Concrete Columns) program described in this paper uses the accumulated experience and knowledge of experts in the field of concrete column design to account for the issues involved in the design in order to make an optimal design proposal for given loadings. The approach used in the program is that of an “expert system” and the program is developed to run on a microcomputer. The developed computer program is interactive, and it incorporates an accurate analysis routine which enables the user to analyze both the sections proposed by the design routine and any other concrete column sections.

The industry foundation class (IFC) standard building model schema is a necessary but not sufficient condition for achieving full interoperability between building information modeling (BIM) tools. Unless each information exchange within construction project workflows has its specific contents and level of detail defined, the breadth and flexibility of the IFC schema leaves room for errors. The national BIM standard approach for resolving the ambiguities of information exchange is based on “use cases,” which precisely define the data required in each information exchange between disciplines in engineering workflows. In this paper, we define specific procedures for developing information delivery manuals (IDM), which capture the use cases and the precise information to be exchanged. We also identify some of the data semantics we found problematic that require workflow specification. We further propose details of the information capture that allow the IDM to serve as a specification for later implementation and testing. The procedures are illustrated using examples from an IDM specification developed for the domain of architectural precast concrete.