土木外文翻譯--學(xué)會發(fā)現(xiàn)改善土木工程項(xiàng)目工作流程的影響

1、<p>　　CHANGCHUN INSTITUTE OF TECHNOLOGY </p><p>　　Learning to see the Effects of Improved Workflowin Civil Engineering Projects</p><p>　　學(xué)會發(fā)現(xiàn)改善土木工程項(xiàng)目工作流程的影響</p><p>　　資料來源：

2、Lean Construction Journal </p><p>　　設(shè)計(jì)題目： 長春市熱電廠辦公樓結(jié)構(gòu)、施工設(shè)計(jì) </p><p>　　學(xué)生姓名： 宗翔宇 </p><p>　　學(xué)院名稱： 土木學(xué)

3、院 </p><p>　　專業(yè)名稱： 土木工程專業(yè) </p><p>　　班級名稱： 土木0942 </p><p>　　學(xué) 號： 0905411242

4、 </p><p>　　指導(dǎo)教師： 沙 勇 </p><p>　　教師職稱： 講 師 </p><p>　　完成時間： 2013/3/26 </p><p&g

5、t;　　2013年 03 月 26 日</p><p>　　“Learning to see” the Effects of Improved Workflow in Civil Engineering Projects </p><p>　　Peter Simonsson1, Anders Bjornfot</p><p>　　2, Jarkko Eriksham

6、mar 3 & still OlofssonThomas4</p><p>　　Understanding & improving workflow </p><p>　　A flow is composed of transformations, inspections, moving and waiting (Koskela, 2000). According to W

7、omack and Jones (2003), workflow refers to the movement of materials, information and resources through a system. To create a smooth flow of work, the availability of materials, information and resources must be controll

8、ed during the whole production process (Thomas et al, 2003). Reducing on-site material handling and lead times through proper workflow management is an important part of the cons</p><p>　　Improving the flow

9、of work </p><p>　　The most readily applicable method for improving workflow is pull production. Pull means that no upstream actor should produce anything until the customer downstream asks for it (Womack and

10、 Jones,2003). In construction, the most recognized and applied tool to generate pull is the Last Planner system of production control. However, there are ertainly other attempts at establishing pull in on-site constructi

11、on of which Line-of-Balance (Seppänen et al., 2010) and pull production of multi-storey hou</p><p>　　Consequently, it is possible to work with workflow at both the early stages of a construction project

12、 using so called proactive workflow methods and during the project execution at the construction site using so called reactive workflow methods (Figure 1): </p><p>　　Proactive workflow management. Aims at re

13、moving hindrances to production workflow in the design phase. Common methods are e.g. improved buildability and proper production planning. Another useful method for proactive workflow management is simulation using for

14、example 4D planning .</p><p>　　Reactive workflow management. Aims at removing hindrances in the production phase so that even workflow is achieve at the construction site. Common methods are e.g. planning fo

15、r pull production and standardizing work tasks. Another useful method for reactive workflow management is to highlight workflow by mapping the value stream</p><p>　　Highlighting workflow </p><p>

16、;　　Value stream mapping (VSM) is an effective method to capture both the material and the information flows of manufacturing, transactional and administrative processes and to provide a good communication tool for practi

17、tioners as well as a reference model for theoretical analysis (Álvarez et al., 2009; Mehta, 2009). By focusing on continuous flows rather than machine, transport or personnel utilization, the likelihood of sub-opti

18、mization is reduced (Ballard et al., 2003). The focus on continuous </p><p>　　VSM is divided into mapping the current, future and an ideal state and the implementation of what is defined as yearly value stre

19、am plans (Rother and Shook, 2004) Khaswala and Irani (2001) argue that VSM is best utilized for high volume production since it is difficult to follow the workflow from finished goods to raw material. However, if the pro

20、cesses are standardized and the project consists of multiple objects, then it is possible to use VSM even for civil engineering projects. Wilson (2009)</p><p>　　Effects of workflow improvements </p>&

21、lt;p>　　A process can be characterized by lead time, inventory and operational costs. Lead time is the time from when a work item enters a process until it exits, i.e. time needed to produce adequate output. Inventory,

22、 is the stock level, or input that the project needs to transform into output. Operational costs are costs connected to the transformation of input into outputs, e.g. wages, rental of machines and other resources, and ov

23、erhead costs. In a normal process, an optimization of either of these </p><p>　　and only by reducing all three or having status quo on two and reducing one will give an improved system (Maskell and Kennedy,

24、2007; Brosnan, 2008). Lead time, inventory and operational costs are actually a transformation of financial terms used to optimize the results of a project; increased net income and at the same time maximizing return on

25、 investment and increasing cash flow (Olhager, 1993). The traditional measures of lower operational costs, lower capital costs and increased sales would </p><p>　　? Smaller capital costs through fewer inven

26、tories. </p><p>　　? Smaller operational costs through less staff. </p><p>　　? Fewer inventories mean smaller storage areas at the construction site. </p><p>　　? Less material han

27、dling and internal transportations. </p><p>　　? Less damaged or obsolete materials and waste. </p><p>　　? More projects in a shorter time mean more income. </p><p>　　Learning to s

28、ee workflow </p><p>　　VSM is divided into mapping the current, future and ideal state (Rother and Shook, 2004). Mapping the current state reveals both value and non-value adding activities. The objective of

29、the future state (to-be scenario) is to create a value stream where every individual process is connected to a customer by either continuous flow or a pull system. The ideal state is a representation of the organization

30、vision; a state to strive for but not necessarily currently attainable due to, for example, a l</p><p>　　Case study research: rebar management in Civil Engineering </p><p>　　Two civil engineerin

31、g projects were studied (Table 1) with focus on workflow during reinforcement fixing. The same contractor carried out both projects, albeit with different management and work crew. The first project represents the curren

32、t traditional state, whereas the second project introduces alternative industrialized production methods, for example prefabricated reinforcement, which here is used to represent an ideal state in bridge construction. Th

33、e first project is also used to analyze </p><p>　　VSM, according to Learning-to-See (Rother and Shook 2004), is used to visualize and analyze the workflow. The method has been modified since it is suggested

34、to work upstream, i.e. from finished goods backwards to raw material that of course is difficult to accomplish in the case of bridge construction as building a bridge can be considered a one-of-a-kind flow as the workcre

35、w,management,site characteristics, etc. are rarely consistent between projects. Therefore, the construction progress was fo</p><p>　　In addition, some of the waiting time for the reinforcement in between act

36、ivities was measured and estimated. It was difficult to establish the waiting time for the current and future states, since at least one ton of reinforcement is lifted upon the superstructure at the same time and after t

37、hat each single rebar is manually transported and fixed on the superstructure. Through this mounting and fixing procedure it becomes difficult to exactly establish the waiting time for each rebar and, hence</p>&l

38、t;p>　　Seeing the potential of workflow improvements </p><p>　　Waste observed in the current state was moving materials around the construction site, waiting for materials, machines or instructions, rework

39、, and interruptions of progressive work. In fact, a study of productivity at the specific bridge indicated that only about 30 % of working time was actually adding any value. Other typical wastes that were observed are p

40、resented in Table 2. By introducing reactive solutions such as a pull system, “milk run” deliveries and improved production planning, the </p><p>　　In the ideal state, much of the reinforcement was pulled ju

41、st-in-time to the construction site, i.e. it came the same day as it was supposed to be fixed into the construction (plus a two day buffer). The ideal state improved the lead time and inventory levels from current state

42、with approximately 90 % (Table 3). Also, the manufacturing cost at site decreased significantly (-68 %) in the ideal state at the expense of an increase in the procurement of the prefabricated rebar structures of approxi

43、m</p><p>　　Discussion & Conclusion </p><p>　　In this paper, we have shown that the performance of civil engineering projects can be improved by allowing the site management to visualize and

44、to see the workflow on the construction site. By ‘learning to see’ workflow, the on-site management is able to understand the potential effect of improving the current workflow. Schematically visualizing the traditional

45、flow of work and merely identifying potential waste, is rarely enough for changing traditional practices. However, with the inclusion o</p><p>　　學(xué)會發(fā)現(xiàn)“改善土木工程項(xiàng)目工作流程的影響”</p><p>　　Peter Simonsson1,

46、Anders Bjornfot</p><p>　　2, Jarkko Erikshammar 3 & still OlofssonThomas4</p><p>　　了解“提高工作流程”</p><p>　　一個流程是由轉(zhuǎn)換、檢查、移動和等待所組成的(Koskela,2000)。 據(jù)沃麥克和瓊斯(2003，工作流程指的是通過一個系統(tǒng)中的材料動態(tài)、信息和資源

47、, 創(chuàng)建一個平滑的工作流程。材料的可用性、信息和資源必須控制在整個生產(chǎn)過程中(Thomas et al,2003)。通過適當(dāng)?shù)墓ぷ髁鞒坦芾?，減少現(xiàn)場材料處理和交貨期限是提高施工生產(chǎn)力方法的一個重要組成部分。 (巴拉德et al。,2003) 根據(jù)Formoso et al 在精益生產(chǎn)改善工作流程中消除浪費(fèi)是一個重點(diǎn)。</p><p>　　沃麥克和瓊斯定義任何人類活動的浪費(fèi),比如吸收資源，過度的生產(chǎn)、不必要的庫存,

48、錯誤的流程,產(chǎn)生不必要的活動和傳遞、產(chǎn)品與過錯, 卻沒有創(chuàng)造任何價(jià)值，然而也沒有滿足客戶的要求。</p><p>　　Koskela在理想條件下確定建筑垃圾低劣的產(chǎn)品質(zhì)量,返工,過度使用剩下的材料,材料處理,</p><p>　　材料存貨,和工作。Mossman認(rèn)為浪費(fèi)應(yīng)該用價(jià)值來定義,即通過創(chuàng)造價(jià)值消除浪費(fèi)。它</p><p>　　應(yīng)該注意,過分強(qiáng)調(diào)減少廢物可以變

49、得適得其反。比如：低庫存或缺乏生產(chǎn)能力的時候,可能導(dǎo)致供應(yīng)鏈中斷。</p><p><b>　　改善工作流程</b></p><p>　　提高工作流最容易適用的方法是拉動式生產(chǎn)。拉動式生產(chǎn)</p><p>　　類似于臺下觀眾的要求決定了演員將要在后面表演中的內(nèi)容。在施工中倍受認(rèn)可和應(yīng)用的工具是 來產(chǎn)生拉動式生產(chǎn)是通過項(xiàng)目經(jīng)理的調(diào)控的。然而,另

50、外一些人在施工現(xiàn)場嘗試建立一種在拉動式生產(chǎn)和多層住宅的</p><p>　　拉動式生產(chǎn)之間的平衡。但是，這也只是少有的例子。</p><p>　　另一種方法來減少浪費(fèi)行為的是標(biāo)準(zhǔn)化工作任務(wù)。這個執(zhí)行工作的任務(wù)在不同建筑施工現(xiàn)場和不同工人中都有差異。工作標(biāo)準(zhǔn)化才能組織化的運(yùn)作。所以,人們需要最有效的完成一個重要的工程時會在決策者和所需資源之間下功夫。通過標(biāo)準(zhǔn)化的流程,生產(chǎn)過程將變得更加強(qiáng)大,

51、導(dǎo)致更卓越運(yùn)營成果,持續(xù)改進(jìn)</p><p>　　和消除“非價(jià)值增加”的活動。</p><p>　　完成正確的工作流程在生產(chǎn)過程中是很重要的。早期的決定 將會影響例如大橋的順利竣工，從而影響工作流程現(xiàn)場。諸如此類的因素：位置、類型、形狀、材料的選擇和細(xì)節(jié)設(shè)計(jì)所有的這些都會影響流程</p><p>　　工作。因此,為了現(xiàn)場施工按照流程進(jìn)行, 需要在經(jīng)濟(jì)利益的角度來控制

52、并且管理設(shè)計(jì)和規(guī)劃。亞當(dāng)斯(1989)指出,成功的關(guān)鍵在于為了項(xiàng)目創(chuàng)造經(jīng)濟(jì)效益刻苦鉆研的早期設(shè)計(jì)階段。 Wong et al。(2004)指出,設(shè)計(jì)決策影響著一幢建筑是以何種方式建成的，并且決定了建筑的類型，或者說建筑材料在建筑過程中的運(yùn)用量，可惜的是，設(shè)計(jì)師們往往缺乏這方面的想法從而無法做出正確的決定。因此,在項(xiàng)目早期開工的時候就采用工作流程的方式，或又叫做所謂的主動工作流方法，我們稱之為活性工作流方法。</p><

53、;p>　　主動工作流程管理，旨在設(shè)計(jì)階段就消除阻礙生產(chǎn)工作流的因素。常見的方法有：改善建筑效益和采用適當(dāng)?shù)纳a(chǎn)計(jì)劃。另一個有用的方法是,模擬使用主動工作流管理，例如4 d計(jì)劃。</p><p>　　無功工作流管理。旨在生產(chǎn)階段就消除那些障礙，這樣即使是現(xiàn)場施工也能能夠達(dá)到施工流程的標(biāo)準(zhǔn)。。</p><p>　　常見的方法是如規(guī)劃拉動式生產(chǎn),規(guī)范工作任務(wù)。另一個有用的方法是加強(qiáng)被動工作

54、流程管理</p><p><b>　　高亮工作流程</b></p><p>　　VSM是一種有效的方法來捕捉既有物質(zhì)和產(chǎn)生的流動信息、事務(wù)和管理流程,并且為專業(yè)人士提供一個于可用于理論分析的參考模型的良好溝通工具。 通過關(guān)注開銷的波動而不是機(jī)器、運(yùn)輸、人員利用率,才能降低局部優(yōu)化的可能性(巴拉德et al。,2003)。關(guān)注連續(xù)流動使承包商到供應(yīng)商,規(guī)范他們的流程,減

55、少次品。向量空間模型分為當(dāng)前狀態(tài)、未來和理想狀態(tài)和年度價(jià)值流計(jì)劃的實(shí)現(xiàn)。Khaswala和伊朗人(2001)認(rèn)為VSM是用于批量生產(chǎn)最佳方式，因?yàn)閺某善返皆系倪^程很難遵循工作流。然而,如果這個過程是標(biāo)準(zhǔn)的并且項(xiàng)目包含多個部分,那么即使是使用向量空間模型對土木工程項(xiàng)目進(jìn)行施工，他都是合理的。威爾遜(2009)認(rèn)為,向量空間模型可以適用于任何業(yè)務(wù)流程包括服務(wù)、產(chǎn)品開發(fā)、生產(chǎn)和辦公流程。</p><p><b&

56、gt;　　改進(jìn)工作流程的影響</b></p><p>　　一段進(jìn)程可以以交付期限,庫存和運(yùn)營成本等為特點(diǎn)。交付期限是從當(dāng)工作項(xiàng)目開始,直到它退出所需要的時間。即，工程需要時間來產(chǎn)生足夠的產(chǎn)量。庫存,是指庫存水平,或是項(xiàng)目達(dá)到目標(biāo)所需要的庫存量。運(yùn)營成本是與完成工程量所需要的付出息息相關(guān)的，例如工資，機(jī)器的租金，其他資源的開銷成本等。正常情況下優(yōu)化這些參數(shù)都會在其他方面產(chǎn)生收益,因此我們有一個優(yōu)化形式。

57、縱觀整個系統(tǒng)，只有減少所有三個因素的影響或目前存在的兩個才能會對系統(tǒng)產(chǎn)生客觀的提升。</p><p>　　交付期限、庫存和運(yùn)營成本實(shí)際上是一個用于優(yōu)化項(xiàng)目的結(jié)果的另類的金融術(shù)語;增加凈收益和在相同的</p><p>　　時間在投資上獲得最多的回報(bào)同時增加現(xiàn)金流量(Olhager,1993)。這個低運(yùn)營成本，低投資的傳統(tǒng)措施增加了利潤，并且會為工程帶來更大的收益。從一個工作流的角度來看,這意

58、味著:</p><p>　　較小的資本成本通過更少的庫存。</p><p>　　小操作成本通過更少的員工。</p><p>　　更少的存貨意味著擁有較小的存儲倉庫的施工現(xiàn)場。</p><p>　　更少的材料處理和內(nèi)部運(yùn)輸系統(tǒng)。</p><p>　　減少受損或過時的材料和廢物。</p><p>　

59、　項(xiàng)目完成用的時間越少意味著獲得的利益越大。</p><p>　　案例研究:鋼筋管理土木工程</p><p>　　研究者對在鋼筋加固過程中的兩個項(xiàng)目進(jìn)行了研究。同樣的承包商進(jìn)行了兩個項(xiàng)目,雖然不同的</p><p>　　管理和工作人員。第一個項(xiàng)目代表了當(dāng)前傳統(tǒng)的狀方法,而第二個項(xiàng)目介紹替代工業(yè)化生產(chǎn)方法,比如用在理想狀態(tài)的橋梁工程中的預(yù)制鋼筋。第一個項(xiàng)目也是用于分析

60、潛在的活性工作流的辦法,即經(jīng)過改進(jìn)的“未來狀態(tài)”。然而,應(yīng)該指出的是,“未來狀態(tài)”橋并不能真正建造起來。相反，從“未來狀態(tài)” 建造的橋來看，這些還都是要依賴于前輩的經(jīng)驗(yàn)。</p><p>　　VSM,根據(jù)“Learning-to see”,用于設(shè)想和分析工作流程。該方法已被修改,因?yàn)樗莻€適得其反的方法,即從成品返回到原料,向后當(dāng)然很難。完善橋梁結(jié)構(gòu)使之成為一座完整的橋的過程可以被認(rèn)為是一個人，一種流程隨著工作的

61、人員、管理制度、工地特點(diǎn)等等,很少有雷同的項(xiàng)目。因此,施工進(jìn)度然后從開始到結(jié)束,收集的數(shù)據(jù)被用在后續(xù)工作中。這些研究是用于創(chuàng)建一個用于分析VSM “當(dāng)前、未來和理想”的狀態(tài),根據(jù)圖3。</p><p>　　這兩個項(xiàng)目的數(shù)據(jù)是作者經(jīng)過很多次深入現(xiàn)場考察得到的。在現(xiàn)場考察，經(jīng)由項(xiàng)目經(jīng)理的協(xié)助得到了工作成果，并且一一得到了驗(yàn)證。然而,考察的主要目的是為了在交付日期和庫存水平中收集一些數(shù)據(jù)。通過收集材料運(yùn)送到現(xiàn)場的數(shù)據(jù)，

62、還有安裝在橋梁里的鋼筋的數(shù)據(jù)得到了交付日期的數(shù)據(jù)。此外,綁扎鋼筋之后的空余時間也被大致估算了下?？紤]到當(dāng)前和未來狀態(tài)，很難最空余時間進(jìn)行預(yù)測,因?yàn)樯蠈咏ㄖ辽儆幸粐嶄摻顚⒁獬?lt;/p><p>　　而在那之后,每個單一的鋼筋是用人工運(yùn)上去和安裝固定的。通過這個安裝和修復(fù)的程序使之變得很難準(zhǔn)確估算建立每個鋼筋的等待時間,因此, 所有鋼筋在上層建筑的總平均等待時間與測量和估計(jì)越來越有關(guān)聯(lián)了。</p>&

63、lt;p>　　看到潛在的工作流程的改進(jìn)</p><p>　　浪費(fèi)在當(dāng)前工程中屢見不鮮。例如材料在施工現(xiàn)場,等待材料、機(jī)器或指令,返工和中斷的有危險(xiǎn)性的工作的時候。事實(shí)上,一項(xiàng)關(guān)于特種橋梁的研究的調(diào)查表明只有大約30%的工作時間實(shí)際上是產(chǎn)生價(jià)值的。其他典型的浪費(fèi)現(xiàn)象都在表2中體現(xiàn)出來了。通過引入反應(yīng)性解決方案如拉動式系統(tǒng),“牛奶運(yùn)行“運(yùn)送和改進(jìn)生產(chǎn)計(jì)劃,當(dāng)前狀態(tài)還是可以改進(jìn)的。改進(jìn)的結(jié)果是,浪費(fèi)高的庫存水平和

64、很長的交付日期是可以減少的。由于其他活動顯著降低，將強(qiáng)化鋼筋的地點(diǎn)安置在工地現(xiàn)場。此外,現(xiàn)金基金被綁在一起在庫存最小化和在某些情況下它可能甚至有可能從客戶端預(yù)付款的利息中賺錢。 </p><p>　　在理想狀態(tài),大部分的鋼筋被及時送到建筑工地,即它

65、到的同一天,它就唄安裝到結(jié)構(gòu)當(dāng)中(加上一個兩天的緩沖)。相比于目前交付期限和庫存，理想型狀態(tài)的水平大約提高到90%的水平。同時,制造成本在現(xiàn)場顯著降低68%。然而，相比于施工期的現(xiàn)場，總體成本還是降低了。</p><p><b>　　討論與結(jié)論</b></p><p>　　在本文中,我們表明,土木工程項(xiàng)目可以通過現(xiàn)場可視化的工作流程來進(jìn)一步的提高業(yè)績。通過“Lear