中華民國內政部建築研究所中華民國內政部建築研究所

一、研究緣起
台灣邁入超高齡社會、少子化及COVID19的衝擊之下，導致營造業嚴重缺工。預鑄工法可大幅減少現場人力需求，具有多樣性，展開多個工作面來生產構件、品質穩定以及縮短工期等各項優點，以因應缺工問題，也能引導國內營造產業技術升級、邁向科技化，達到營建自動化的目標。因此推動預鑄工法使得營造業可以技術升級，不僅能夠因應缺工的問題，促進營建產業節能減碳與數位化發展，更是國家營造產業邁向科技化必要的作為。
鑑於預鑄工法在建築設計、施工流程、作業程序都與傳統工法有所差異，然而目前國內僅有部份科技業廠房使用預鑄工法，一般建築使用預鑄工法仍屬少數，因此一般建築師較少接觸。緣此，本研究目的為編寫一本手冊使建築師等專業技術人員快速掌握預鑄工法，將技術加速導入一般建築及達到預鑄建築造型多元化。
根據國家發展委員會2022年8月「中華民國人口推估（2022年至2070年）」，預計2025年後65歲以上人口將占總人口比率超過20%同時，勞動人口也將低於總人口數的2/32039年後65歲以上人口更將占總人口比率超過30%，我國營建產業缺工的情況將雪上加霜。
預鑄工法除了可精簡人力、縮短工期以因應缺工問題，並且品質穩定可同時間進行各環節工作項目；藉由推展預鑄工法引導國內營造產業技術升級、邁向科技化，實現營建自動化的目標是國家建造產業邁向科技化的必然趨勢，為未來必要的舉措。
當前我國營建產業已有少數業者投入預鑄工法，然而除了成本及工期考量外，許多建築師、營造廠商受限於對該工法的瞭解不足不敢貿然投入，對於跨足預鑄工法仍持觀望態度。因此若能提供預鑄工法的相關介紹與導入預鑄工法時的注意事項等資訊，將有助於未來預鑄工法的推廣與發展。
二、研究方法與過程
本研究透過收集預鑄相關文獻資料，其中包括了國內外相關預鑄手冊及相關工法技術設計書籍、BIM導入預鑄相關文獻以及傳統發包、統包之相關文獻等，以作為後續手冊編寫之基礎;另外，也透過預鑄廠實際參觀、國內學者、建築師及預鑄廠專家訪談收集目前國內預鑄現況及未來展望等相關專家建議以利於後續手冊編寫;在手冊編寫同時也召開了多次專家座談會以及手冊編審會議，期望可以找出預鑄廠與建築師之間的共識，最後進行統整分析，作為手冊編寫之重要參考依據。
三、重要發現
(一)預鑄工法於公共工程採購發包上面臨之困境
本研究針對預鑄工法在統包及傳統發包模式下之推動流程進行了分析，目前國內公共工程之採購類型可大致可區分為統包及傳統發包（設計及施工分開發包）兩大類，在導入預鑄工法時，統包方式基本上較無問題，因統包廠商一開始就會找預鑄廠協助，但若採傳統發包方式，負責設計的建築師因較少有預鑄設計的經驗，多半無法獨立完成預鑄設計；另外在施工廠商部分，因應國內採購法規要求，材料設備供應廠商至少須有三家以上，但因目前國內預鑄廠商數量較少且產線多已緊繃，導致建築師在規劃設計時及營造廠在投標時較為困擾，本研究建議政府單位後續應積極輔導更多預鑄廠商，以解決目前公共工程發包時所面臨之困境。
(二)國外預鑄推行成功的思維模式
本研究建議未來可參考國外預鑄成功推行的因素，例如:日本在30年前就已成功推動預鑄工法於國內的應用，其成功推動之原因之一與設計思路有關，日本的設計思路主要於規劃設計時建築師及結構技師就已掌握相關預鑄設計之概念，例如:主筋可適量加大等，可與現場混凝土具有同等效能的PC構造設計，所設計出來的設計成果，傳統與預鑄工法皆可做，讓營造廠可自行評估選擇；而另一方面，各個施工單位也有注意到相關設計要領，在施工時各業者僅作分割接合動作，不會影響到其他單位，因此本研究建議可參考日本成功推行的思維模式。
(三)預鑄工法已克服過去防水問題
在過去文獻中有提到台灣早期有一部分是因漏水問題才導致預鑄推廣失敗，而近年來相關技術逐漸發展純熟，過去所遇之漏水問題也隨之解決，且現階段技術已發展到多重防水設計，完全克服過去對於預鑄工法容易導致漏水的問題。
(四)預鑄工法適用之對象
本研究透過多次專家訪談、座談會以及編審會議中所獲得之共識為現階段社宅較適合導入預鑄，因社宅一般量體較大，且普遍對於工期上有一定的要求，在執行上會比較有效率，且專家們也有提到在社宅推動預鑄工法的導入將可帶動民間一般住宅後續跟進，因此目前是很好的時機點，建議後續可將社宅導入預鑄工法列為優先推動方向。
(五)預鑄廠使用之BIM軟體應用模式
本團隊於研究中發現預鑄廠商使用之BIM軟體主要使用針對結構之TEKLA軟體，而其他包括結構、建築、機電設計以及施工管理單位所使用的BIM軟體皆為AutodeskRevit，與預鑄廠使用之軟體較為不同。本研究也透過專家訪談得知預鑄廠商不會另行設置BIM部門，BIM建置模式主要採各單位針對自己專業方面進行模型建置，後續再透過內部進行整合及檢討。通常在大型預鑄廠設計部門會依造建築、結構設計製作施工圖，而預鑄構件則照尺寸規格生產，因此，通常BIM模型無太大之差異性，另外，預鑄於建築生命週期中屬於混凝土構件生產之專業廠商，其模型與結構相同，因此，無須修改其BIM模型。
(六)預鑄工法導入建築工程設計宣導手冊之內容研擬
第一章預鑄工法之簡介及發展沿革
該章節分為(1)預鑄工法之優勢(2)預鑄工法發展沿革(3)預鑄工法種類，共三小節，本研究於於手冊中最初會先進行簡單介紹，後續針對內容應涵蓋其預鑄工法之優勢以及國內外從過去到現今發展之預鑄進行簡介。最後，介紹各種預鑄工法之類型、具體效益以及所遇到之瓶頸。
第二章不同採購模式對應之預鑄工程導入方式及適用性
該章節分為(1)預鑄於傳統發包採購模式下之適用性(2)預鑄於統包採購模式之適用性(3)兩種採購模式之差異，共三小節，本研究於於手冊中會分別對於傳統發包及統包之採購模式進行簡介。後續對於傳統發包及統包之採購模式導入預鑄時之適用性進行探討，最後對於兩種發包模式進行比較。
第三章預鑄工法設計各階段所需注意之事項
該章節分為(1)規劃階段(2)基本設計階段(3)細部設計階段(4)建築師於設計中常見之相關問題，共四小節，本研究將該章節視為手冊核心，因本研究成果之預鑄工法推動手冊主要針對建築師來進行設計，而設計規劃會分為上述三個階段，分別會介紹於各個階段之注意事項。本章第四節則針對應在其內容提到各階段之設計時所需注意事項、與預鑄廠、業主以及各系統專業人士的溝通以及整個設計流程進行詳細的介紹.建築師在傳統工法轉換為預鑄工法設計時之差異及參考原則以及各階段應配合提送之相關資料進行簡介。
第四章結合BIM技術建構模組化預鑄元件技術分析
該章節分為(1)業界常使用之BIM軟體及用途簡介(2)BIM整合方法探討，共兩節，首先會針對業界常用之BIM軟體進行簡要之介紹，也會針對使用此類軟體於預鑄工程中的一般流程及可應用場景說明。
第五章實際案例介紹
該章節分為(1)國內實際案例探討(2)特殊案例探討，共兩節，本研究會透過實際案例得知於設計時會遭遇的困難以及了解不同預鑄的應用，使建築師能更快的掌控預鑄相關技術的使用方法，也會於第二節針對特殊多元造型預鑄以及社宅進行詳細的介紹。
(七)政策上推行預鑄之積極性作法
本研究建議未來政策上可參考國外實際政策修訂案例，或許國外曾遇過之問題可變為國內預鑄推動之借鏡，未來推行時也可知道如何避免國外所遇之狀況，例如:容積獎勵、證照獎勵等推動方式。
(八)未來可推行預鑄專業技術及設計講習
本研究建議未來可推行建築師、結構、機電技師等專業人士之預鑄工程相關課程，使這些專門技術人員補足應有的專業素養及相關預鑄工程設計能力，方能逐漸擴大整個預鑄市場，使預鑄真正普及化。因預鑄工程產業特殊，其設計牽扯到製造技術、效率及成本控制等因素，目前國內在預鑄設計上多仰賴大型預鑄廠之設計部門與建築師互相配合，且國內沒有太多相關可供參考之資料，因此建議趁推動時讓配合之相關專門技術人員補足相關知識，初期推廣較有難度，但可透過導入相關誘因使專業人士願意參與，例如:預鑄工法講習證照制度、講習費用補助等。

I.Research Background
Taiwan's entry into a super-aging society, a declining birthrate and the impact of COVID 19 have led to a serious shortage of workers in the construction industry. The pre-casting method can greatly reduce the on-site manpower demand, has the advantages of diversification, multiple working faces to produce components, stable quality and shortened construction period, etc., in order to cope with the problem of labor shortage, and can also guide the domestic construction industry to upgrade its technology and move towards science and technology, so as to achieve the goal of construction automation. Therefore, promoting the pre-casting method enables the construction industry to upgrade its technology, which can not only cope with the problem of labor shortage, promote energy conservation, carbon reduction and digital development of the construction industry, but also be a necessary action for the national construction industry to move towards science and technology. 
In view of the fact that the pre-casting method is different from the traditional construction method in terms of architectural design, construction process and operating procedures, at present, only some science and technology factories use the pre-casting method, and the pre-casting method is still a minority in general buildings, so the general architects have less contact.  Therefore, the purpose of this study is to compile a manual to enable architects and other professional and technical personnel to quickly master the pre-casting construction method, accelerate the introduction of technology into general buildings and achieve the diversification of pre-cast building shapes.
According to the National Development Council's August 2022 population projections (2022-2070), it is expected to be 65 years after 2025The population over the age will account for more than 20% of the total population, while the working population will account for less than two-thirds of the total population, and after 2039, the proportion of the population aged 65 and over will exceed 30%., the shortage of workers  construction industry will be even worse. 
In addition to streamlining manpower, shortening the construction period to cope with the problem of lack of labor, and stable quality, all links of work projects can be carried out at the same time; by promoting the precast method, guide the domestic construction industry to upgrade technology, move towards science and technology, and achieve the goal of construction automation is a necessary action for the national construction industry to move towards science and technology in the future.
II.Research Method and Process
In this study, we collected relevant literature materials of precast, including related precast manuals and related construction technology design books, BIM import precast related literature, and traditional contracting and turnkey related literature, etc., as the basis for the preparation of subsequent manuals. In addition, through the actual visit of the precast plant, interviews, scholars, architects and pre-foundry experts, relevant expert suggestions such as the current situation and future prospects of the precast were collected to facilitate the preparation of the subsequent manual. At the same time as the preparation of the manual, a number of expert symposiums and manual editing meetings were held, hoping to find out the consensus between the pre-foundry and the architect, and finally conduct a unified analysis as an important reference for the preparation of the manual. 

III.Important Findings
1.The dilemma faced by the precast method in the procurement and awarding of public works
This study analyzes the promotion process of the precast method in the turnkey and traditional contracting mode, the current procurement types of public works can be roughly divided into two categories: turnkey and traditional contracting (design and construction sub-development contracting), when introducing the precast method, the turnkey method is basically less problematic, because the turnkey manufacturer will find the assistance of the precast factory at the beginning, but if the traditional contracting method is adopted, the architect in charge of the design is less experienced in precast design, most of them cannot complete the precast design independently; in addition, in the part of the construction manufacturer, according to the requirements of procurement regulations, there must be at least three or more material and equipment suppliers, but because the number of precast manufacturers is small and the production line is tight This study suggests that government units should actively counsel more pre-cast manufacturers in the future to solve the current dilemma faced by public works contracts.
2.Foreign precast promote successful thinking patterns 
This study suggests that in the future, we can refer to the factors of the successful implementation of foreign precast, for example: Japan has successfully promoted the application of precast method in China 30 years ago, and one of the reasons for its successful promotion is related to design ideas, which are mainly based on the planning and design of architects and structural technicians who have mastered the concept of relevant precast design, such as the main reinforcement can be appropriately enlarged, etc., and the PC structural design with the same efficiency as the on-site concrete can be designed, and the design results can be done by both traditional and precast methods, so that the construction plant can evaluate and choose by itself; on the other hand, each construction unit has also paid attention to the relevant design essentials, and each industry only performs the segmentation and joint action during construction, which will not affect other units, so this study suggests that the thinking model successfully implemented in Japan can be referenced. 

3.The pre-caster method has overcome the waterproofing problems of the past
In the past literature, it was mentioned that some of Taiwan's early days were due to water leakage problems that led to the failure of precast promotion, and in recent years, the relevant technology has gradually developed and sophisticated, and the water leakage problems encountered in the past have also been solved, and the current stage of technology has developed to multiple waterproof designs, completely overcoming the problem that the precast method is easy to cause water leakage in the past.
4.To whom the precast method applies
The consensus obtained in this study through many expert interviews, symposiums and editorial meetings is that the social house is more suitable for the introduction of precast at this stage, because the social house is generally large, and generally has certain requirements for the construction period, and it will be more efficient in implementation, and experts also mentioned that promoting the introduction of the precast method in the social house will drive the follow-up of the general house, so it is a good time to introduce the precast method in the social house as a priority promotion direction.
5.BIM software application mode used in pre-foundries
In our research, the team found that the BIM software used by precast manufacturers mainly uses TEKLA software for structures, while other BIM software used by structural, architectural, electromechanical design and construction management units is Autodesk Revit, which is different from the software used by precast. This study also learned through expert interviews that precast manufacturers will not set up a separate BIM department, and the BIM construction model mainly adopts each unit to build models for its own professional aspects, and then integrate and review it internally. Usually in the design department of large-scale precast plants, construction drawings will be made according to the architectural and structural design, and pre-cast components are produced according to size specifications, so usually the BIM model is not much different, in addition, precast in the building life cycle belongs to the professional manufacturer of concrete component production, its model is the same as the structure, therefore, there is no need to modify its BIM model. 
6.The precast method was introduced into the content of the construction engineering design advocacy manual
Chapter 1 Introduction and development of the precast method
This chapter is divided into (1) the advantages of the precast method (2) the development history of the precast method (3) the types of the precast method, a total of three subsections, this research will initially be briefly introduced in the manual, and then the content should cover the advantages of the precast method and the development of precast at home and abroad from the past to the present. Finally, the types, specific benefits and bottlenecks encountered by various precast methods are introduced.
Chapter 2 Introduction methods and applicability of precast projects corresponding to different procurement modes
This chapter is divided into (1) the applicability of precast in the traditional outsourcing procurement mode (2) the applicability of precast in the turnkey procurement mode (3) the difference between the two procurement modes, a total of three subsections, this study will introduce the traditional contracting and turnkey procurement models respectively in the manual. In this paper, the applicability of the traditional procurement mode of contracting and turnkey procurement is discussed when precast, and finally the two contracting modes are compared.
Chapter 3 :Matters to be paid attention to at each stage of the design of the precast method
This chapter is divided into (1) planning phase, (2) basic design phase, (3) detailed design phase, and (4).This study regards this chapter as the core of the manual, because the precast method promotion manual of this research results is mainly aimed at architects, and the design planning will be divided into the above three stages, which will introduce the precautions at each stage. Section 4 of this chapter provides a detailed description of the considerations that should be made at the various stages of design, communication with the precast manufacturers, the owner, and system professionals, and the entire design process. The differences and reference principles of the architect when converting the traditional construction method to the precast method design, as well as the relevant materials submitted at each stage, should be briefed. 
Chapter 4: Technical Analysis of Modular Precast Components Constructed Combined with BIM Technology
This chapter is divided into (1) introduction to BIM software commonly used in the industry and its use and (2) discussion of BIM integration methods, a total of two sections, first of all, a brief introduction to the commonly used BIM software in the industry, and also for the general process and application scenarios of using such software in precast projects.
Chapter 5: Introduction to Practical Cases
This chapter is divided into (1) domestic actual case discussion and (2) special case discussion, a total of two sections, this study will understand the difficulties encountered in the design through actual cases and understand the application of different precast, so that architects can control the use of precast related technologies faster, and will also introduce in detail in the second section for special multi-shape precast and social houses.
7.Implement the proactive practice of precast in policies
This study suggests that future policies can refer to foreign actual policy revision cases, perhaps the problems encountered abroad can be used as a reference for domestic precast promotion, and in the future implementation can also know how to avoid foreign situations, such as: volume incentives, license incentives and other promotion methods. 
8.In the future, precast professional technology and design courses can be implemented
This study suggests that in the future, precast engineering related courses for architects, structures, mechatronics technicians and other professionals can be implemented, so that these professional and technical personnel can supplement their professional qualities and related precast engineering design capabilities, so as to gradually expand the entire precast market and make precast truly popular. Due to the special nature of the precast engineering industry, its design involves manufacturing technology, efficiency and cost control and other factors, at present, the precast design relies on the design department of the large-scale precast plant and the architect to cooperate with each other, and there is not much relevant information for reference, so it is recommended to take advantage of the promotion to let the relevant professional and technical personnel supplement the relevant knowledge, the initial promotion is more difficult, but through the introduction of relevant incentives to make professionals willing to participate, such as: precast method training license system, Subsidies for lecture expenses, etc. 
IV.Suggesttions
Suggestion#1
medium-term and long-term suggestion- Counselling the establishment of more pre-cast manufacturers to solve the dilemma of public works procurement"
Authority in Charge: Taiwan Cement Products Industry Association 
Assisant Authority: Private pre-foundries
In response to the relevant provisions of the Government Procurement Law, if the traditional contracting mode is adopted for public works on the Taiwan, there must be at least three suppliers of materials and equipment, and the number of large-scale pre-casting manufacturers on the Taiwan is currently small and the production line capacity is tight, so this study suggests that the organizer can assist in the establishment of more pre-casting manufacturers as soon as possible to solve the current dilemma faced by public works procurement.