Preliminary inspection about the profit of 3D data in public works

Transcription

1 icccbe 2010 Nottingham University Press Proceedings of the International Conference on Computing in Civil and Building Engineering W Tizani (Editor) Preliminary inspection about the profit of 3D data in public works Kageyama Teruaki, Kawakami Masakazu & Miyamoto Katsunori Japan Construction Information Centre, Japan Haishima Hironobu & Nakayama Toshimi Ministry of Land, Infrastructure, Transport and Tourism, Japan Abstract The Ministry of Land, Infrastructure, Transport and Tourism announced the implementation of CALS/EC Action Program 2008 for further improving the infrastructure production system on 31 st March To achieve this goal, model projects utilizing ICT are planned to be carried out in the next year. Before the commencement of model projects, we reviewed recent trend to utilize threedimensional data on domestic and overseas construction fields. As a conclusion through preliminary inspection based on the existing bridge design, we could verify positive effects given by the visualization of three-dimensional data delivered over the current construction business processes. Keywords: CALS/EC, bridge, 3D-CAD, business process, visualization 1 Introduction The Ministry of Land, Infrastructure, Transport and Tourism of Japan (MLIT) promulgated the CALS/EC Action Program 2008 (AP2008), three-year implementation plan of promoting CALS/EC initiative, on 31st March AP2008 is focused on establishing ICT-based civil engineering production process in six priority fields in order to improve construction productivity. Among six priority fields, the 3rd target stated as utilization of digital data throughout the lifecycle process from survey, plan, design, construction to maintenance, and the 4th target as quality improvement of public works by introducing information integrated construction technology, which are recognized as important activities to improve productivity and efficiency of public works, especially through ICT-based design and construction as well as sophisticated management. Along with these targets, MLIT decided to carry out pilot projects adopting information integrated construction since 2009 in order to prove effectiveness and establish technology and process for quality control, finished work quality inspection, schedule control, safety management and environment management. In prior to execution of pilot projects, benefit and effect of adopting 3D data in bridge design and construction were estimated. This paper reports the results of the preliminary inspection about the profit of 3D data in public works.

2 2 Outline of the public works used in this study 2.1 Specification of the works A case of a steel bridge constructed by MLIT was used for the study. The specifications of the works are as follows: length of the bridge: L= m carriageway width: 7.25m ~ 7.00m horizontal alignment: straight ~ R=1,000m superstructure type: 4 span continuous non-composite steel girder substructure type: reversed T type abutment, wall type pier detailed design year: 1999 construction year: 2000 ~ 2001 Figure 1 shows the general drawing of the bridge. Figure 1, General drawing of the bridge. 2.2 Sub-processes for benefit estimation Benefit in a scene of adopting 3D data was estimated at 5 sub-processes in approximate design and detailed design stages where effect of 3D data utilization is expected. Table 1 shows 5 selected subprocesses. Table 1. Sub-processes for benefit estimation. Sub-processes in design stage Approximate design Scenes Confirmation of design conditions Scene 1 Selection of alternative bridge types Scene 2 Examination of main factors Scene 3 Landscape analysis Scene 4 Detailed design Examination of detailed factors Scene 5 Assumptions for benefit estimation are as follows: 3D data are supposed to be utilized in the following processes as consistent data flow within the current work process. Comparison shall be focused on a scene where 2D drawing is limited to express and communicate correct information such as corners, scrambles or design concept. Comparison shall be focused on scenes where rationalization of processes is expected through omission or unification of sub-processes by using 3D data.

3 2.2.1 Approximate design (Scene 1 to 4) Scene 1: Confirmation of design conditions This scene is to identify the object which the bridge lays over, and decide main construction conditions. It is an important process to start bridge planning and the initial work by using information transferred from survey stage. Influences of the result of this process to the following processes are also broad and large. Scene 2: Selection of alternative bridge types This scene is to select and determine the scope of alternative plans of different bridge types. This is the most basic examination process and has broad influence to the following processes. Moreover, benefit estimation lies on terrain analysis such as excavation impact area analysis, which 3D data can contribute a lot. Scene 3: Examination of main factors This scene is to design details of bridge structure. There expect a lot of benefit by adopting 3D design because examination covers all over the structure and 3D vision can help precise examination of scrambles at member level. Scene 4: Landscape analysis This scene is to design bridge shape from basic simple bridge shape design to complex shape design with consideration of local factors and environmental issues. There also expect a lot of benefit by adopting 3D design because CG and 3D perspective view can help local residents understand the project easily Detailed design (Scene 5) Scene 5: Examination of detailed factors This scene is to adjust scrambles between superstructure and substructure which are two major parts of bridge structure. This is the final stage of structure design. Therefore, it is required to achieve adjustment in mm levels, where 3D visualization can help intensive and correct decision making, and then can reduce errors and redesigning. 3 Creation of 3D models and execution of preliminary inspection 3.1 Specifications of the system used 3D CAD software was used for the preliminary inspection. The specification of the system is as follows Software and hardware Software: Autodesk Civil 3D 2009 Computer: Dell optiplex755 CPU: Intel(R) Core(TM)2 Duo CPU 2.33GHz Memory: 1.95GB RAM HDD: 150GB Operator 12 year experience on AutoCAD 3.2 Execution of the preliminary inspection Figure 2 shows 3D models created for the preliminary inspection. The results of the preliminary inspection are listed below. Table.2, 2D and 3D design show a comparison of the design work.

4 Figure 2, 3D models created for the study. Table 2. Comparison works. Sub-processes in design stage Approx imate design Detaile d design Confirmation of design conditions Selection alternative bridge types Examination main factors Landscape analysis of of Examination of detailed factors Scenes Works 2D 3D design design Vertical section of geological profile 0.0h 3.0h Cross sectional drawing of river 1.0h 4.0h Scene 1 Examination of Abutment 1.0h 2.0h Examination of Bridge pier 2.0h 2.0h Examination of Freeboard(clearance) 1.0h 1.0h Sub total 5.0h 12.0h Examination of Skew bridge 4.0h 1.0h Scene 2 Decide on the position of Abutment 4.0h 1.0h Decide on the position of Bridge pier 4.0h 1.0h Examination of excavation line 3.0h 3.0h Sub total 15.0h 6.0h Examination of superstructure 15.0h 20.0h Scene 3 Examination of substructure 8.0h 10.0h Examination of ancillary facilities 8.0h 8.0h Examination of Erection schedule 5.0h 8.0h Sub total 36.0h 46.0h Scene 4 Landscape simulation 32.0h 1.0h Scene 5 Decide on the all works 20.0h 13.0h Total (hour) 108.0h 78.0h

5 3.2.1 Scene 2: Selection of alternative bridge types It is assumed that 3D data was created in the former stage as design conditions confirmation stage, and that examination report which is usually written in 2D design was not required in 3D design. Therefore, it is unnecessary to draw basic design condition and can be substituted by 3D simulation of structure arrangement, and thus achieves large cost and time reduction Scene 3: Examination of main factors Large benefit can be expected in achieving consensus among people concerned, with the help of visual presentation of design comparison or examination. However, large additional workload is required in comparison with current 2D drawing. Examination report is unnecessary to be written, however, it is necessary to be resolved how to express and transfer design concept on 3D models Scene 5: Examination of detailed factors In 2D design, substructure and superstructure are designed independently, and thus it is likely to make scramble errors between sub and super structures. On instead, 3D design can express both structures in one model, which makes it easy to examine and confirm scramble related information such as vertical height. Therefore, design quality is expected to be highly improved. Moreover, attribute information at detailed design level is to be added at this stage, which can eliminate most work of following detailed design drawing creation work except processing for expression of numerical values of size or length. Figure 3 shows reinforcing bar arrangement. Figure 3, Reinforcing bar arrangement 4 Remarks and problems 4.1 Remarks Approximate design Confirmed benefits in design stage are as follows. Time of 2.4 times of a 2D design is necessary for a 3D design in confirmation of design condition stage because of 3D model creation. However, 3D design is effective in other stages utilising 3D models. Landscape design (Scene 4) has achieved significant efficiency.

6 Examination accuracy is improved because various conditions can be examined flexibly by means of simulation. Design quality is improved because detailed examination of scrambles is possible. Visual presentation can help consensus making without misunderstanding. Work efficiency is improved through unification and omission of sub-processes. Moreover, possibility of work efficiency improvement was pointed out in the cases that corners, scrambles and concept of the structure, where 2D design is hard to express, can be visualized by using 3D data. 4.2 Problems to be solved In order to utilize 3D data in the present work process, there exist some problems to be solved as follows. Numerical values of size or length are hidden and difficult to be recognized. Quantity calculation is difficult Additional work is required which is not required in 2D drawings. Problems first and second may depend on 3D CAD software functions. However, dimension line is difficult to be displayed on most 3D view of the 3D structure model. Moreover, attribute data as quality and type of material of the structure shall be displayed precisely at member parts level, and quantity calculation shall be agreed with the Standard manual for quantity calculation for public works and the Standard cost estimation rule for public works. 5 Conclusion In Japan, CALS/EC initiative has been promoted in order to improve productivity of public works construction, and digital data exchange is getting popular and contributes to rationalization of construction production process. It is expected that benefit of information sharing prevailed over the lifecycle and construction process can be rationalized and renewed, if information can be circulated over the processes of survey, plan, design, construction and maintenance. Establishment of new information sharing environment based on 3D data is expected to contribute productivity improvement of construction production process. Therefore, it is necessary to conduct research and development work continuously and intentionally and aiming to establish the 3D technology as a core technology for construction information circulation. Acknowledgements The authors would like to gratefully acknowledge the members who cooperated concerned in this project. References MINISTRY OF LAND, INFRASTRUCTURE, TRANSPORT AND TOURISM (MLIT): CALS/EC Action Program 2008 (AP2008)