Brian Hobbs

DEVELOPMENT OF AN INTEGRATED INFORMATION RESOURCE BASE FOR 4D/VR CONSTRUCTION PROCESSES SIMULATION

Abstract The objective of this paper is to report on the development of an integrated database to act as an information resource base for 4D/VR construction process simulation. A comprehensive database was designed, implemented and populated with the School of Health Construction Project (a £8 million, three-story development at the University of Teesside campus). The database is composed of a core database of building components which is in turn, integrated with a CAD package (AUTOCAD 2000), a Project Management Package (MS Project) and Graphical User Interfaces. The core database was designed using Standard Classification Methods (Uniclass). One of the benefits of using the Uniclass method, a part from providing standards for structuring building information, is that it provides a media for integrating Product Breakdown Structure (PBS) with Work Breakdown Structure (WBS). This is an important aspect for delivering a meaningful 4D model. Integrated interfaces between MS Access Database, AutoCAD Drawings and MS Project Schedules were developed and implemented. Furthermore, the British Standards of layering convention (BS 1192-5) was adapted and implemented and justification for this is given in the part 2 of this document. The database was populated with detailed 2D drawings (whole building and M&E), schedules of work and resources of the School of Health Project. This paper is also addressing object definition, structuring the data, and establishing the relationships and dependencies within the data set, the WBS and building objects as well as modelling the building in 3D in order to capture the essential space- and time-critical attributes of tasks. Practical application of database throughout the construction process has been highlighted and discussed.

Development of automated communication of system for managing site information using internet technology

Abstract The construction industry is highly fragmented compared with other manufacturing industries. The degree of this fragmentation is unparalleled in any other sector with significant impact on productivity and performance. Many research studies have developed and proposed a number of integrated process models. Unfortunately, they are unable to formalise how communication and information exchange within the construction process can be achieved, without duplication or lost in quality. A move away from the traditional sequential process to reciprocal interdependency processes no doubt place heavy demand on communication and information flow. This problem is widely acknowledged and many of the proposed IT solutions are less practicable to be attractive to practitioners in the industry. Any IT-dependent solution must start with optimisation and better uses of the readily available IT- hard- and software. This paper describes a collaborative research study being undertaken between the University of Teesside and an international contracting organisation based in the UK. The goal of the research is to develop a methodology and a system that will ease and improve communication and exchange of data and information between the construction project team. The paper reports on an IT-based tool for site document management as a first phase of the project. It provides an automated integrated environment for communication, retrieval, storage and distribution of project documents between the construction project team. The structure and development of the system are described with reports of its implementation and performance on the site.

Developing a virtual reality based methodology for people with dementia: a feasibility study

The aim of this study was to examine the feasibility of virtual reality (VR) technology for use by persons with dementia (PWD). Data were obtained directly from six PWD regarding their experiences with a virtual environment (VE) of a large outdoor park. A user-centered method was developed to assess: (a) presence; (b) user inputs; (c) display quality; (d) simulation fidelity; and (e) overall system usability. The extent to which PWD could perform four functional activities in the VE was also investigated (e.g., mailing a letter). In addition, physical and psychological well-being of PWD while interacting with the VE was assessed objectively by recording heart rate during the VR sessions and subjectively with discrete questionnaire items and real-time prompts. Symptom profiles associated with simulator sickness were assessed with an adapted version of the Simulator Sickness Questionnaire. The study found that PWD to some extent experienced presence; perceived that objects were realistic and moved naturally; generally felt in control of the interaction; and demonstrated little difficulty using a joystick for navigation. The study also demonstrated that VR is an appropriate medium for assessing functional behavior within the context of an ecologically valid VE. PWD did not experience any significant increase in symptoms associated with simulator sickness, or detriments to their psychological and physical well-being. These findings demonstrated that it is feasible to work in VEs with PWD.

The performance of unreinforced masonry walls subjected to low-velocity impacts: experiments

Abstract Impact tests on a total of 21 full-scale unreinforced free-standing brickwork and blockwork walls have been performed in the laboratory using novel drop hammer/rotating quadrant apparatus. The impact loading generated in the laboratory had similar basic characteristics to accidental vehicle impacts (i.e. similar peak impact force and duration). The main variables investigated were wall length, wall thickness, masonry unit type/strength, impact location and end conditions. A number of different failure modes were identified. Mortar bonded walls subjected to a mid-height, mid-length, out-of-plane impact loading were observed to resist the loading in two phases: initial elastic action until fracture occurred, followed by gross displacements, resisted by friction at the base and both out-of-plane and in-plane inertial forces. When weak masonry units were used front face vertical fracture lines either side of the impact location were observed; when stronger units were used front face diagonal fracture lines were observed. Walls impacted close to their ends were observed to be significantly less capable of resisting impact loadings.

Flowshop scheduling model for bespoke precast concrete production planning

Bespoke precast concrete products are particularly designed and custom made for a construction project. The production planning of these products is complicated that considers important concerns, i.e. the reliability of the product delivery programme, the short lead‐time competitiveness, and the effective utilization of purpose‐built precast moulds. The planning has a high impact on the success of the production. The characteristics of the bespoke precast production are formulated with the flowshop scheduling technique so that an effective production plan can be arranged to meet these concerns. Genetic algorithm is used in the scheduling optimization. Its multi‐objective function includes total flowtime, total machine idle time, and total tardiness and earliness. After the model formulation, sensitivity analyses are conducted on the three models parameters namely the number of mould availability, the processing time changes, and the weighting of the multi‐objective function. The proposed model is anticipated to support the planners to arrange economic and efficient production plans. Also, it can be used to determine the suitable number of moulds, the accuracy of the processing time estimation, and the weighting strategy of the multi‐objective optimization.

Stockyard layout planning in precast concrete products industry: a case study and proposed framework

Management of the stockyard layout in the precast concrete products industry is very important for efficient storage and dispatch of the concrete products. The industry uses the make-to-stock principle in production to meet the seasonal demand (high in summer and low in winter) from the construction industry. In order to stabilize production output and cater for the huge demand in summer, stock is built up during the winter and spring period. The concrete products are kept in stock for 4–5 months. As 2000≈3000 different precast concrete products are produced, and the products have different size, weight and handling requirements, determination of appropriate stockyard location for the products constitutes a complex process. This paper describes some ongoing research that is focused on identifying the appropriate methodology for designing and managing the stockyard layout that ensures efficient storage and dispatch of products, and provides ease of rotation of products within the yard. An integrated simulation model employing artificial intelligence methods has been proposed to evaluate ‘what-if’ scenarios and recommend a suitable methodology for the management of stockyard space for precast concrete products. This paper presents the findings from a case study, which includes work-study, frequency analysis of historical order data. The paper also introduces the specifications, processes and outline prototype of the proposed model. A general purpose simulation language (SIMAN) based software, ‘Arena 4.0’ (Systems Modelling Corporation), has been selected to develop the prototype simulation model and ILOG views and rules have been considered to generate a knowledge-based stockyard layout.

The performance of unreinforced masonry walls subjected to low-velocity impacts: mechanism analysis

Abstract The development of a rigid-body mechanism analysis capable of estimating the likely response of an unreinforced masonry wall subjected to an out-of-plane impact loading is described. The method automatically identifies the out-of-plane sliding mechanism likely to be most critical for a particular impact location, from a library of five possible mechanisms. Initially, a fracture-line analysis is performed to estimate the out-of-plane force required to crack the wall. Subsequent gross displacements of the wall panels formed are calculated using an iterative dynamic analysis. The fracture energy associated with initial crack opening is included in the calculations and checks are also conducted to determine whether the mode of failure changes during the impact event. Additionally, the possibility that wall rocking can occur, either on its own or simultaneously with the out-of-plane sliding mechanisms is considered. Results from the mechanism analysis model are compared with the experimentally observed results described in a companion paper. It was found that reasonable agreement was obtained for most of the walls subjected to mid-wall impacts, provided ‘dynamic’ rather than quasi-static values for the masonry flexural strength were used in the analysis. Sensitivity studies indicated that wall thickness and the coefficient of base friction were particularly important parameters. The analysis can readily be modified to approximately simulate the interaction between a wall and moving vehicle and is currently being extended to deal with reinforced masonry walls.

Transfer of impulsive loading on cladding panels to the fixing assemblies

The fixing assemblies for prefabricated cladding panels on buildings, are often designed on an empirical basis, to support the dead weight of the panel, wind loads and possibly temporary loads arising during construction. If, subsequently, the design loads are accidentally exceeded but the panel is undamaged; it may be necessary to check the condition of the fixings. A physical check would require costly dismantling and reconstruction of the panel but, as an alternative, this paper presents an analysis of the force transferred to cladding fixing assemblies when the panel is subjected to impulsive loading, using the finite element analysis program, DYNA3D. The results were validated with experimental results from impact tests on a steel plate supported on four steel bars. Having obtained this validation, a finite element analysis was then carried out to determine the response of fixings for panels under different levels of blast loading using two different models for the panel-fixing assemblies. The first model considers only the effect of out-of-plane fixing, whilst in the second model both the out-of-plane fixings and in-plane fixings are considered. It was observed that forces transferred to fixings include an axial force, shear forces, and bending moments and these force components can vary along the length of the fixing. Inspections of cladding panels, after being subjected to impulsive loads, often show that the connection between the fixing and the panel and between the fixing and the support structure are more vulnerable to impulsive loading than the panel itself. The FE analysis has shown that forces in the fixings are related to the dynamic response of the cladding panel; hence damage to the fixings could be deduced from damage to the panel.

Ultrasonic Nde for Assessing the Quality of Structural Brickwork

Abstract The need for the development of non-destructive methods for evaluating structural brickwork is outlined and different approaches to the application of NDE are reviewed. An approach based on the separate evaluation of the bricks themselves, the mortar and the most important variable in practice, the workmanship, is advocated. Anevaluation method usingchanges in ultrasonic pulse transit timeasa measure of variations in quality is developed based on a range of test data. The approach is shown to be capable of detecting potential construction errors, such as the use of under strength mortar or the incomplete filling of the mortar joints.