Integrated assessment method for building life cycle environmental and economic performance

Life cycle assessment (LCA) is a powerful tool to identify a building’s environmental impact throughout its life cycle. However, LCA does have limits in practice because it does not consider the economic aspect of project implementation. In order to promote LCA application, a more comprehensive evaluation of building life cycle environmental and economic performance must be performed. To address these issues, we propose life cycle green cost assessment (LCGCA), a method that combines LCA with life cycle costing (LCC). In LCGCA the building’s environmental loads are converted to environmental costs based on the trading price of CO₂ certified emission reductions (CERs). These environmental costs are then included into the building life cycle cost. Subsequently an evaluation index of green net present value (GNPV) for LCGCA can be obtained. A governmental office building in Beijing was studied using LCGCA. Several design options were compared and the sensitivity of the CER price was analyzed. The research also shows that conclusions reached by LCGCA may be different from those of traditional LCC, which does not include environmental costs. The application of LCGCA needs the support of environmental policies. A sound environmental tax mechanism is expected to be established in China soon, which will enable LCGCA to be a useful tool to guide sustainable building design efficiently.     

Economic analysis of a shopping center in seismic zone

Life cycle cost (LCC) is an important factor in economic analysis in order to cover all expected costs and benefits for an economic life. If a decision has to be made for investment purposes then damage cost incurred due to an earthquake should also be taken into account. Therefore, the total LCC of a structure in a seismic zone should be evaluated in terms of, not only its initial cost, expenditure and income but also earthquake damage cost. This paper provides an LCC analysis for economic evaluation of a shopping center located in a seismic zone. The effects of monthly income, recovery periods, initial cost, discount rate and occurrence time of an earthquake on total LCC are observed throughout the analysis period.     

政府工程采购的全寿命周期成本分析

全寿命周期成本为政府采购提供了全新的视角,它要求政府采购应追求产品的全寿命周期成本最小,尤其应该关注环境成本和社会成本,以提高整体社会效益。介绍了全寿命周期成本概念,分析了政府工程采购的全寿命周期成本构成,提出了全寿命周期成本估算方法,介绍了估算中有关参数的确定方法。     

Flat roofing systems: towards integrated techno-economic analysis

A methodology presented for an integrated analysis of roofing systems is used to assess different flat roofing systems in Israel. This approach can help designers with integrating technology issues, performance management and life cycle costs for component systems. The performance and durability survey observed an overall premature failure rate of 30%. The principal cause of failure was poor maintenance and inappropriate use. Life cycle costing analysis indicated that polyvinyl chloride membranes offered the highest life cycle costing effectiveness within Israel, primarily because of low maintenance expenditures. Despite its low initial capital investment, the single-layered modified bitumen roofing system exhibited high life cycle costs due to its short service life and consequent replacements costs.     

Service life prediction of exterior cladding components under standard conditions

An empirical method was developed for the prediction of the service life of building components, based on an evaluation of their actual performance and on the identification of failure mechanisms affecting their durability. The service life of exterior components subjected to normal service conditions is predicted. Four types of exterior claddings are exemplified: cementitious mortar, synthetic rendering, ceramic mosaic, and wet‐fixing stone cladding. The proposed prediction models yield high degrees of fit to the data (R ² in the range of 0.86 to 0.93 at a 0.0001 level of significance). Life cycle costs (LCC) analysis – following service‐life prediction results – leads to the conclusion that maintenance and replacements costs account for 10–80% of initial capital costs. Synthetic rendering exhibited the highest LCC effectiveness, reflecting durability and low capital costs. The method can be used for planning preventive maintenance, evaluating economic implications of failures, and planning service life.     

Theory of valuing building life-cycle investments

The physical adaptability of buildings is very important in today's fast-changing business environment. The actors who invest in long-term adaptability are positioned better to the changes during the life cycle of a building. This conceptual paper argues that the current dominating real estate (property) investment analysis theories do not accommodate enough building design-related information (i.e. physical asset characteristics), which results in long-term loss of competitiveness and unsustainable use of built environment resources. It is demonstrated that physical asset characteristics can create valuable real options that should be acknowledged in real estate investment analysis and management. The real estate investment literature has not so far been able to produce a widely accepted financial model for justifying life-cycle investments. A theory is proposed here that can be used to value life-cycle investments in buildings. This new theory combines of real options valuation, investment analysis and building component life-cycle design. These themes are used to formulate a conceptual framework for valuing life-cycle investments. The framework is intuitive and transparent, and it can be easily added to current spreadsheet investment analysis tools.     

Performance analysis of the building envelope: A case study of the Main Hall,Shinawatra University

The envelope of the Main Hall, Shinawatra University has been designed to provide protection from energy gain. According to initial estimates, the Main Hall could achieve an overall thermal transfer value (OTTV) of 10.16 W/m², which is four times lower than those recommended by the Thai national standard. This study aims to evaluate the actual energy performance of the Main Hall building envelope using field measurements and simulations. The air temperature, surface temperature, and relative humidity were measured at frequent intervals, both indoors and outdoors. Hourly average meteorological data for insolations were utilized in order to calculate the solar gain by light transmission. Based on the empirical data, the energy fluxes through the envelope on eight different orientations were simulated and the average value was found within 7% of the estimated OTTV. Using the same empirical data for the outdoor condition, simulations of other common types of building envelope in Thailand were carried out for comparison. The results of the analysis show that the Main Hall's lightweight and highly insulated building envelope outperforms other commonly used heavyweight envelopes in preventing building energy gain in the hot-humid climate of Thailand. Although the use of the lightweight and highly insulated envelope helps reduce the operating and investment costs of the air conditioning system as well as the cost of building structure, it also increases the investment cost of the envelope substantially. However, the life cycle cost analysis (LCCA) reveals that the life cycle cost (LCC) of the Main Hall envelope is the most economical, and the increased investment cost of the Main Hall envelope requires a discounted payback period of only 3–5 years, depending on the envelope types used in the comparison. Furthermore, it should be noted that greater savings and a more favorable pay back period could be obtained if this highly energy efficient envelope is applied to other typical buildings, especially high-rise structures in urban areas.     

Establishing the true costs and benefits of environmental protection and enhancement in the aquatic environment

In the aquatic environment, a number of techniques are available to evaluate environmental benefits arising from improvements in water quality. However, such techniques do not account for the environmental costs of implementing a given quality change, for example those associated with the construction and operation of necessary treatment processes. Life cycle assessment is a technique that enables the nature of environmental impacts arising from the construction and operation of processes to be established. Although comprehensive assessment of all options is likely to be uneconomic, focusing on a number of key system inputs and outputs offers the possibility to include such impacts cost effectively in investment appraisal.     

Life quality time allocation index – an equilibrium economy consistent version of the current life quality index

The definition the life quality index for a country as originally suggested by Nathwani, Lind and Pandey is based on the gross domestic product (GDP), the expected life in good health at birth, and the fraction of life time the anonymous citizen of the country is occupied with money making work. The LQI is invented to serve as a mean to evaluate how much money that reasonably can be allocated to safety improving investments by simply requiring constancy of the LQI. By choosing that the importance of increments in the two first variables should be measured relative to the current values of the variables themselves, the relative increment of the LQI becomes defined as a convex combination of the two relative increments. The combination parameter is obtained by an optimality argument about the anonymous citizen’s distribution of his or her time between free time and work time. In the original definition this equilibrium economy principle is applied under the assumption that the GDP is directly proportional to the work time fraction. This direct proportionality has been relaxed by the first author in two earlier papers with an essential effect on the combination parameter. The present paper presents a further development casting the definition into dimensionless quantities that make the index get a pure unit of time and not the somewhat obscure unit as a power product of a money unit and a time unit. To avoid confusion, this new variant of the LQI is called the life quality time allocation index (LQTAI). Moreover, the Danish data from the period from 1948 to 2003 show good agreement with the relation between the productivity and the work time as obtained from the optimality argument. The data fitting leads to an estimate of the combination coefficient of c = 0.092 together with a reduction factor of r = 0.92 to be applied to the total life expectation at birth to obtain the expected life in good health. Among other infinitely many choices of (c, r) there are (0.085, 1.0) and (0.1, 0.85).     

Empirical tests for identifying leading indicators of ENR Construction Cost Index

Engineering News-Record (ENR) publishes its Construction Cost Index (CCI) monthly. CCI is the weighted average price of construction activities in 20 United States (US) cities. CCI has widely been used for cost estimation, bid preparation and investment planning. Cost estimators and investment planners are not only interested in the current CCI, but also are interested in forecasting changes in CCI trends. However, CCI is subject to significant variations that are difficult to predict. An important step towards forecasting CCI trends is to identify its leading indicators. The research objective is to identify the leading indicators of CCI using empirical tests. The results of Granger causality tests show that consumer price index, crude oil price, producer price index, GDP, employment levels in construction, number of building permits, number of housing starts and money supply are the leading indicators of CCI. The results of Johansen’s cointegration tests show that money supply and crude oil price are the leading indicators with long-term relationships with CCI. These findings contribute to the body of knowledge in CCI forecasting. CCI can be predicted more accurately using its leading indicators. Cost estimators and capital project planners can benefit from better forecasting through reduction in uncertainty about future construction costs.     

全寿命周期理论下的工程造价控制

全寿命周期控制,就是对工程项目规划决策、设计、施工、生产运营直到报废的各个阶段进行全盘考虑,进行综合造价控制。笔者在全寿命周期理论的视角下主要研究决策设计阶段和招投标阶段两个关键节点的工程造价控制。     

Life cycle cost considerations in project appraisals of collision-free roads

In the last decade, many single carriageway roads in Sweden have been converted to collision-free roads as a cost-effective alternative to conventional motorways. Investigations have concluded that the road type has been successful in reducing the number of fatal accidents, despite increased operation and maintenance costs. In recent years, the focus has shifted to converting narrower roads which are anticipated to further increase operation and maintenance cost but also complicate traffic management during road works. There are concerns that when life cycle cost is considered in the investment assessment the socioeconomic profitability could be reduced. This article examines this issue by first assessing changes in costs for operation and maintenance using a life cycle cost analysis approach applied on a case study. The results from the analysis were thereafter integrated into a cost–benefit analysis to assess changes in costs in relation to benefits in improved traffic safety and travel time. The analysis indicated profitability even with substantial increase in operation, maintenance and road user work zone costs. Results are discussed from project implementation and road management perspectives.     

高速公路沥青路面全寿命经济分析

为了进一步提高公路建设的投资效益,在分析高速公路沥青路面耐久性和寿命周期关系的基础上,建立了沥青路面全寿命周期费用模型,该模型综合考虑了投资方案的初始修建费、未来的养护维修费、用户费用和寿命期内的其它相关费用。介绍了沥青路面全寿命经济分析的方法,讨论了全寿命经济分析过程中需要重点考虑的两个问题——沥青路面使用性能衰变的预测和维修时机、策略的选择,并对两种不同结构类型的沥青路面进行了实例分析。本文的研究可以为当前新形势下的公路建设项目投资决策和运营管理提供参考。     

Life‐Cycle Engineering of Bridges

Life‐cycle engineering, as being developed at Lehigh University's Engineering Research Center for Advanced Technology for Large Structural Systems (ATLSS), is a comprehensive, systematic methodology which treats each stage in the life of a structure as part of an integrated process. It considers both performance and cost throughout the life of a structure, thus supporting a more balanced view of investment based on construction, operation, renewal, replacement and decommission issues. Consideration of all phases of the life‐cycle supports intelligent and informed decision‐making. Lehigh has an on‐going program of research on methodologies and information systems embodying the life‐cycle engineering approach which is being incorporated into a decision support system for life‐cycle engineering of bridges. The authors describe a prototype model which provides bridge engineers and owners with analytical information to more effectively integrate life‐cycle considerations into engineering decisions concerning bridge decks.     

屏蔽门系统的全寿命周期成本管理与分析

屏蔽门系统近年来在轨道交通领域得到广泛应用。以10个车站的具体数据为例,从投资、运行和维护等方面,分析了屏蔽门系统设备全寿命成本的影响因素,并提出了一系列合理、可行的处理措施,以降低成本和提高成本管理效率。     

浅议建设单位对工程造价的管理

工程是指一切建设工程。对业主而言,工程造价的含义就是指一项工程预期开支或实际开支的全部固定资产投资费用,即工程投资费用。一般来说,建设工程都具有周期长、生产要素价格变化频繁、产品单件性、固定性等特征,使得建设工程的造价复杂多变,因此,业主方对其管理应贯穿于工程建设的全过程。本文根据工作经验,介绍业主方在工程造价管理过程中的作用和应注意的问题。     

Multiobjective optimisation algorithm for sewer network rehabilitation

Understanding of deterioration mechanisms in sewers helps asset managers in developing prediction models for estimating whether or not sewer collapse is likely. Effective utilisation of deterioration prediction models along with the development and use of life cycle maintenance cost analysis contribute to reducing operation and maintenance costs in sewer systems. This article presents a model for life-cycle maintenance planning of deteriorating sewer network as a multi-objective optimisation problem that treats the sewer network condition and service life as well as life-cycle maintenance cost (LCMC) as separate objective functions. The developed model utilises Markov chain model for the prediction of the deterioration of the network. A multi-objective genetic algorithm is used to automatically locate an appropriate maintenance scenario that exhibits an optimised tradeoff among conflicting objectives. Monte Carlo simulation is used to account for LCMC uncertainties. The optimisation algorithm provides an improved opportunity for asset managers to actively select near-optimum maintenance scenario that balances life-cycle maintenance cost, condition and service life of deteriorating sewer network. A case study is used to demonstrate the practical features of developed methodology.