In this paper, we are targeting on reinforcement works which has serious influence on the quality of the superstructure from among various kinds of construction work, focusing on information necessary for the building process from design to construction. We clarified the issue for utilize information on reinforcing work by Field survey and analysis. As a result of this, we will summarize basic knowledge on new methods of management of production information utilizing ICT.
 We investigated the workflow of the reinforcing bar bending factory, interviewed the rebar sub-contractors and observed the reinforcing work on the construction site; therefore, we grasp of the production information in the reinforcing work in detail. In addition, we investigated where ICT is used in the flow of information. As a result, the following knowledge was obtained.
 1) Production process can be categorized into four types, "drafting", "bar bending", "placing of rebar", "inspection".
 2) Information on the management items "drafting" and "inspection" is obtained from the structure drawing and the construction drawing. Because their information is an element unit.
 3) Management items of "bar bending" and "placing of bar" obtain information from "bending schedule" and "bending instruction tag". Because their information corresponds to materials.
 4) The digital information of the rebar bending process is used to create of "reinforce drawing", "bending schedule", "bending instruction tag", and it is applied to progress management and inspection in the reinforcing bar bending factory. Among them, software that creates "bending instruction tag" is developed by reinforcing bar bending factory himself.
 In addition to hearing within the reinforcing bar bending factory, interviews to a foreman of reinforcement works in the construction site were conducted twice and process analysis was performed. As a result, the following knowledge was obtained.
 1) Inside the reinforcing bar bending factory, workers are himself conduct sampling inspection of bending reinforcing bars. The confirmation items at that time are the information on the dimensions stated in "bending instruction tag".
 2) After bending work at the factory, "bending instruction tag" is used until distribution to work place on site. At the placing of bar used information of "reinforce drawing", and for final inspection "structure drawing" is used.
 3) The sub-contractor of the reinforcing bar performs the self-check during the placing of bar. A general contractor will inspect after the placing of bar is completed.
 We clarified the following contents from the investigation of the actual situation of the whole process of reinforcement works and workflow analysis.
 1) In reinforcement work information for connecting design and construction, the bend and check information is intensive on "bend command tag". The information described in the "structural diagram" is referred to in the creation of "construction drawing", "reinforce drawing" and "bending schedule", but bar bending, transportation, distribution and placing of bar bending Information of instruction tag is used.
 2) Since the information to be referred to changes during the process, it has the risk of mistakes in converting information.
 The workflow of the reinforcement work was partially optimized because the work was divided finely. Therefore, a mechanism for preventing a mistake of work between each work was not constructed. From now on, we think that the division of responsibility and roles in the production process in rebar work progresses more. In order to overcome the situation, it is possible to improve "productivity" by proceeding with "visualization" and "sharing" of information on bending processing and arranging muscle, and by not sending defective products to the subsequent process, and using ICT and BIM are important.

抄録全体を表示

 Building projects need many decision-making, and clients cooperate to decide with architects, supervisors, general contractors and other consultants in projects. Especially in Japan, because the project members trust each other and the ability of Japanese general contractors is excellent, clients often make a decision in construction phase. However, the laws in Japan don't define client's decision in construction phase clearly, and that often makes some kinds of risk (e.g., design change, delay of projects, and high cost). This paper aims to clarify factors and influence of client's decision-making in construction phase in Japan.
 There are three main laws related construction projects in Japan, Building Standards Act, Act on Architects and Building Engineers, and Construction Business Act. In addition, there are several standard specifications of construction work and standard forms of contract in Japan. These three laws and some standards define client's decision-making as follows. [1] if they find some mistakes in drawings in construction phase, clients must make architects correct it. [2] by agreement with the project member, clients can change drawings in construction phase. [3] if the design change affects structure, clients must perform structural calculation and obtain the application of building confirmation. [4] In case that it is reasonable to select in construction phase such as color, material and equipment, clients can select them in construction phase after clarifying in drawings.
 Therefore, we took the questionnaire about current status of client's decision-making involved in reinforcement work, steel work, exterior work, and equipment work. Questionnaire was an open-ended question method and composed of three questions as below. [1] what kind of client's decision-making is there? [2] what factors of decision-making are there? [3] what influence of decision-making is there? The sample was restricted to people in construction project and the respondents were belonged to clients, developers, architects, and general contractors. A total of 78 questionnaires were distributed by e-mail and 14 samples were collected.
 The results of survey revealed the difference of client's behavior between 4 works. In reinforcement work and steel work, clients do not decide and instruct the number of reinforcement and performance of a steel member directly. However, clients affect these works indirectly. In design phase, sometimes, clients do not decide certain use of space because they want to follow a trend or they have not decided tenant yet. In this case, clients decide these things in construction phase and that makes change the position of partition and piping sleeve in reinforcement work and steel work. In exterior work, it is reasonable to decide color and material of exterior in construction phase because clients cannot judge from only drawings whether the design is good. General contractors make mock-up for clients to check the design and clients decide or change the design detail directly. In equipment work, clients affect it in two ways. In case that it is reasonable to decide it in construction phase, clients decide the position, number, and performance of equipment directly. On other hand, in the case that clients decide use of space in construction phase, the use and size of the room determine the required position, number and performance of equipment.
 Finally, in order to analyze factors of client's decision-making, we applied the fishbone diagram analysis. Fishbone diagram is the tool for identifying the root causes of problem, which was “Client's decision-making in construction phase” in this paper. This diagram has 3 main causes (project member, building type, building element) and 42 secondary causes. In addition, it was modeled how client's decision-making in construction phase affects the post-process of four works.

抄録全体を表示

京成線のユーカリが丘駅前センターでは, 鉄筋コンクリート(RC)造の高層集合住宅3棟(29階建て1棟と31階建て2棟)が建設されている。わが国では6年前に初めて超高層RC工法によるRC造集合住宅が建設され, そのときは1フロアを12日で施工した。その後, 施工の経験を積み, 工事は6日/1フロアの施工スピードで行えるようになった。本稿は, 高層RC造の施工スピードとして記録的に速い4日サイクル/1フロアを達成することのできた新工法について述べるものである。

抄録全体を表示

In recent years, it has become an issue in the construction management to improve productivity. Therefore, the authors surveyed man-hour rate of construction management business. The results of the survey, we revealed 436 tasks, and able to grasp the respective man-hours. In addition, we specified the business that should considered improvements, and discussed measures of improvements.

抄録全体を表示