超高层建筑结构生命周期多维度经济成本评估及优化方法

超高层建筑结构具有结构体系复杂、结构功能多样、生命周期长、投资量大、持有人固定不变等特点,其全生命周期成本费用包含初始费用、维护费用、灾害失效费用以及拆除费用等多项费用。为了实现超高层结构全生命周期经济利益最大化而采用的生命周期经济评估方法通过方案对比、构件对比、费用项目等多维度对超高层结构成本费用进行管理。使用该方法能够在项目初期就对结构项目进行全面的评估与优化,同时,一个超高层建筑的实例将被引用来说明其有效性与适用性。     

节能住宅全寿命周期费用影响因素仿真研究

从对节能住宅进行全寿命周期费用分析的重要性出发,通过对影响节能住宅全寿命周期费用的因素入手,建立了基于系统动力学的全寿命周期费用影响因素系统模型,并以兰州鸿润园节能住宅作为实证研究对象,运用系统动力学 Vensim-PLE 仿真软件进行分析,结果显示:节能率的大小、是否考虑资金时间价值和寿命期的长短均对全寿命周期费用具有显著影响,节能程度越高的住宅,在考虑资金时间价值的情况下,使用寿命越长,它的全寿命周期费用也就越低。分析结果对消除人们在节能投入认识上的“误区”、政府建设行政主管部门组织编制建筑节能方面设计规范与标准、开发商和业主建设与购买节能住宅均提供了可靠的经济性参考依据。     

绿色建筑全寿命周期成本控制管理研究

本文对绿色建筑全寿命周期的影响因素进行了全面分析,探讨了绿色建筑全寿命周期成本控制管理的方法,提出了加强绿色建筑全寿命周期成本控制管理的政策建议,为全面推广绿色建筑全寿命周期成本控制管理奠定了基础。     

Life-cycle cost analysis as a tool in the developing process for new bridge edge beam solutions

Currently in Sweden, the life-cycle measures applied on bridge edge beams may take up to 60% of the total costs incurred along the road bridges’ life span. Moreover, significant disturbances for the road users are caused. Therefore, the Swedish Transport Administration has started a project to develop alternative edge beam design solutions that are better for society in terms of cost. The purpose of this article is to investigate whether these proposals can qualify for more detailed studies through an evaluation and comparison based on a comprehensive life-cycle cost analysis. The alternatives including the standard design are applied to typical Swedish bridges. The impact of the values of the parameters with the largest influence is investigated by sensitivity analyses. Results with different life-cycle strategies are shown. The positive influences in the total life-cycle cost of a stainless steel reinforced solution and of the enhanced construction technique are estimated. The concrete edge beam integrated with the deck seems to be favourable, which is in line with international experience observed. Different designs may be appropriate depending on the bridge case and the life-cycle strategy. The Swedish Transport Administration will carry out a demonstration project in a bridge with one of the proposals.     

建筑给排水节能技术综述

从原理、特点和适用条件等各方面综合论述了建筑给排水行业中各种常见的节能技术,为绿色节能建筑的给排水设计提供借鉴。     

网壳结构寿命周期总费用的计算方法研究

现代结构系统在灾害中产生巨大经济损失的特点,使人们意识到在结构设计之初就对结构的寿命周期总费用进行有效评估、并反过来指导工程设计具有重要意义。对网壳结构寿命周期总费用的计算方法进行研究,分别提出初始造价、维护费用和失效损失的计算公式,并考虑寿命周期内网壳结构可能受到的荷载发生的概率,建立寿命周期总费用的计算方法,编制网壳结构寿命周期总费用的计算程序。通过一具体的网壳结构工程算例验证上述方法和程序的有效性。研究结果表明,网壳结构初始造价的追加投资会由于结构使用过程中失效损失费用的减小而得到补偿,而寿命周期总费用最小正是结构设计的最优状态,按照现行规范设计方法得到的结构配置方案不一定是寿命周期总费用最小的方案。     

A multi-objective feedback approach for evaluating sequential conceptual building design decisions

Conceptual design decision-making plays a critical role in determining life-cycle environmental impact and cost performance of buildings. Stakeholders often make these decisions without a quantitative understanding of how a particular decision will impact future choices or a project's ultimate performance. The proposed sequential decision support methodology provides stakeholders with quantitative information on the relative influence conceptual design stage decisions have on a project's life-cycle environmental impact and life-cycle cost. A case study is presented showing how the proposed methodology may be used by designers considering these performance criteria. Sensitivity analysis is performed on thousands of computationally generated building alternatives. Results are presented in the form of probabilistic distributions showing the degree to which each decision helps in achieving a given performance criterion. The method provides environmental impact and cost feedback throughout the sequential building design process, thereby guiding designers in creating low-carbon, low-cost buildings at the conceptual design phase.     

保温材料在围护结构中的全寿命周期经济评价

运用全寿命周期经济评价理论,建立围护结构全寿命周期经济评价模型,并通过实际工程分析和计算建筑围护结构采用节能材料后的全寿命周期成本,从而得出结论:建筑围护结构运用节能材料不仅降低建筑能耗,同时也降低了建筑全寿命周期成本。     

Life-cycle of structural systems: recent achievements and future directions

Structural systems are under deterioration due to ageing, mechanical stressors, and harsh environment, among other threats. Corrosion and fatigue can cause gradual structural deterioration. Moreover, natural and man-made hazards may lead to a sudden drop in the structural performance. Inspection and maintenance actions are performed to monitor the structural safety and maintain the performance over certain thresholds. However, these actions must be effectively planned throughout the life-cycle of a system to ensure the optimum budget allocation and maximum possible service life without adverse effects on the structural system safety. Life-cycle engineering provides rational means to optimise life-cycle aspects, starting from the initial design and construction to dismantling and replacing the system at the end of its service life. This paper presents a brief overview of the recent research achievements in the field of life-cycle engineering for civil and marine structural systems and indicates future directions in this research field. Several aspects of life-cycle engineering are presented, including the performance prediction under uncertainty and optimisation of life-cycle cost and intervention activities, as well as the role of structural health monitoring and non-destructive testing techniques in supporting the life-cycle management decisions. Risk, resilience, sustainability, and their integration into the life-cycle management are also discussed.     

The influence of design variables and environmental factors on life-cycle cost assessment of concrete culverts

The objective of this article is to evaluate the influence of material, structural design variables and exposure conditions on the service life and cost effectiveness of precast concrete culverts in Canada. This investigation will assist practicing engineers to account for long-term performance and integrate life cycle analysis into design and construction decisions. The design variables considered in this study include the percentage of ground granulated blast furnace slag (GGBFS) as cement replacement, reinforcing steel cover depth and culvert size. This study proposes the usage of a life-cycle cost assessment approach to compare different culvert designs on an economic basis which accounts for the design variables and the impact of CO₂ production and uptake over the life of a culvert from cradle to grave. Analysis of each culvert scenario includes the cost of the initial production of CO₂ during the manufacturing process as well as the cost savings that were incurred due to the uptake of CO₂ through carbonation processes. Overall, the present cost of the culverts is controlled by the GGBFS content and the reinforcing steel cover depth while carbonation processes have a relatively small economic impact.     

Life-cycle cost-oriented multiobjective optimization of composite frames considering the slab effect

The life-cycle cost-oriented design philosophy is a promising tool for building resilient cities as it helps in gaining insights into the impact of hazard-induced damage and repair of civil and infrastructure systems. In this study, a socioeconomic parameter-independent practical formulation was introduced for life-cycle cost analysis by combining the economic loss rate associated with different damage limit states and cloud analysis-based probabilistic seismic demand model. A framework for life-cycle cost analysis-based seismic design optimization was proposed using an emerging nature-inspired algorithm, namely, the multiobjective cuckoo search. By considering an eight-story prototype composite frame, the framework was used to determine the trade-off design alternatives between competing optimization objectives. Conventional and improved fiber models were developed to comparatively evaluate the influence of the slab spatial composite effect on Pareto optimal designs. The key drivers of change in three cost indicators were identified using generalized linear models. The result indicates that the overstrength factor is the critical design parameter affecting the initial construction, seismic damage, and life-cycle costs, with statistical significance at the 0.001 level.     

Integrated life-cycle design of building enclosures

In spite of the progress in developing methods and tools to support sustainable building design, there is still a lack of a formal approach to bridge the “no man’s land” gap between the traditional building engineering disciplines, and between these and the architecture, to achieve the level of building integration required for sustainability. This paper presents an integration framework that aims at facilitating the inclusion of life-cycle considerations in the design process from the outset, so that materials and systems are selected not only from environmentally friendly resources, but most importantly, to match service life performance expectations. The framework describes an iterative methodology to evaluate these expectations in practice, which is based on an understanding and modeling of the dynamics of the built environment to which materials, components, and systems are exposed. Quantitative methods and test protocols can be incorporated into the framework for assessing function-performance aspects of alternative solutions. Due to its complexity stemming from its inherent exposure to variable environmental loads and its multi-functionality, the framework focuses on addressing the life cycle of the building enclosure system. It is expected that the organization of the underlying principles of building life-cycle performance described in this paper will become a knowledge core that will facilitate a more integrated treatment of buildings in research, education, and practice.     

Life-cycle carbon and cost analysis of energy efficiency measures in new commercial buildings

Energy efficiency in new building construction has become a key target to lower nation-wide energy use. The goals of this paper are to estimate life-cycle energy savings, carbon emission reduction, and cost-effectiveness of energy efficiency measures in new commercial buildings using an integrated design approach, and estimate the implications from a cost on energy-based carbon emissions. A total of 576 energy simulations are run for 12 prototypical buildings in 16 cities, with 3 building designs for each building-location combination. Simulated energy consumption and building cost databases are used to determine the life-cycle cost-effectiveness and carbon emissions of each design. The results show conventional energy efficiency technologies can be used to decrease energy use in new commercial buildings by 20-30% on average and up to over 40% for some building types and locations. These reductions can often be done at negative life-cycle costs because the improved efficiencies allow the installation of smaller, cheaper HVAC equipment. These improvements not only save money and energy, but reduce a building’s carbon footprint by 16% on average. A cost on carbon emissions from energy use increases the return on energy efficiency investments because energy is more expensive, making some cost-ineffective projects economically feasible.     

基于模糊综合评判的结构寿命周期总费用评估

结构寿命周期总费用评估是实施基于性能的抗震设计的关键问题,其中失效损失期望评估中结构失效概率的计算往往需要多次结构重分析,计算量很大,成为结构寿命周期总费用评估中的一个主要问题。本文利用模糊综合评判理论进行结构寿命周期损失期望的评估,以失效概率方法评估结果为参照,研究了隶属度函数的不同形式、结构不同重要性对模糊评判方法结果的影响,并计算了钢筋混凝土框架算例。结果表明,利用模糊综合评判进行结构损失期望评估,可以在保证一定精度的前提下,大大简化了失效损失期望评估的计算量。     

价值工程在设计阶段的应用对建筑物造价的影响

介绍了工程设计阶段对建筑物造价的影响，分析了在设计阶段对工程全寿命造价的重要性和现存的问题。列举一项分部工程说明设计选型对建筑施工阶段的费用及效益产生的重要影响。指出在设计阶段运用价值工程是解决这一问题的一种思路，并初步提出如何在设计阶段运用价值工程的方法。     

Beyond the code: Energy, carbon, and cost savings using conventional technologies

As states in the U.S. adopt new energy codes, it is important to understand the benefits for each state and its building owners. This paper estimates life-cycle energy savings, carbon emission reduction, and cost-effectiveness of conventional energy efficiency measures in new commercial buildings using an integrated design approach. Results are based on 8208 energy simulations for 12 prototypical buildings in 228 cities, with 3 building designs evaluated for each building-location combination. Results are represented by easy-to-understand mappings that allow for regional and state comparisons. The results show that the use of conventional energy efficiency technologies in an integrated design framework can decrease energy use by 15-20% on average in new commercial buildings, and over 35% for some building types and locations. These energy reductions can often be accomplished at negative incremental life-cycle costs and reduce a building's energy-related carbon footprint by 9-33%. However, generalizing these results on energy use, life-cycle costs, and carbon emissions misses exceptions in the results that show the importance of location-specific characteristics. Also, states do not appear to base energy code adoption decisions on either potential energy savings or life-cycle cost savings.     

Assessing the efficacy of stainless steel for bridge deck reinforcement under uncertainty using Monte Carlo simulation

Bridge engineers seek new materials, configurations and other design elements to minimise rehabilitation frequency and intensity over the facility life and hence, reduce life-cycle cost. This article discusses the potential of stainless steel as a bridge deck reinforcement material. The superiority of stainless steel over traditional steel was evaluated on the basis of long-term agency cost and user cost. Using data from a US Midwestern state, the analysis was carried out for a majority of analysis scenarios. For the deterministic situation, the use of stainless steel as bridge deck reinforcement material was found to yield a significantly higher initial cost but drastically reduced the overall life-cycle costs, and thus is more cost-effective over the long term. For the uncertainty situation, Monte Carlo simulation was used to generate the distributions of the life-cycle cost for the stainless and the traditional steel reinforcement materials. It was found that the life-cycle cost for the stainless steel option stochastically dominates the life-cycle cost for traditional steel. Thus, under an uncertainty situation, the use of stainless steel as bridge deck reinforcement material is also more cost-effective compared to traditional steel.     

A model for earthquake risk management based on the life-cycle performance of structures

Over 50 years of design life, buildings are exposed to different magnitudes and frequencies of earthquakes that require consideration of life-cycle cost (LCC). The LCC entails quantifying the building performance under seismic hazard and investments throughout the life of the structures. Traditional LCC utilises probabilities of being in different damage states. However, for buildings with inherent irregularities (e.g. vertical irregularity and plan irregularity), these probabilities are not readily available. In this paper, a system-based approach, utilising fuzzy set theory, is used to quantify the possibility of being in different damage states. The analysis is limited to study the effect of seismic exposure on the building LCC. The proposed method is illustrated with two case studies, a six-storey reinforced concrete (RC) building located in Vancouver, Canada, and vulnerability of an urban centre with 1000 RC buildings. Furthermore, sensitivity analysis is carried out to highlight the impact of different building performance modifiers on the LCC.     

设计阶段建筑结构系统造价的优化分析

通过对建筑结构系统分析,说明了设计建筑结构的基本原则和计算建筑结构造价的基本方法,建立了建筑结构系统经济优化的通用模型。结合常见的钢筋混凝土结构,具体分析了优化模型在钢筋混凝土结构设计阶段的应用。通过编译计算机程序,可以较方便地求解最佳结构设计方案。文中以某四层双跨框架结构为例,对比分析了该框架结构的初始方案与优化方案,发展经优化后的方案造价比初始方案造价节省了２．９％,经济效果比较明显。     

Life cycle cost implications of energy efficiency measures in new residential buildings

The importance of the built environment from an environmental impact and energy use perspective is well established. High thermal efficiency of the constructed building envelope is a key strategy in the design and construction of buildings which limit use of active space conditioning systems. Australia's current housing stock is thermally poor and national energy performance standards are relatively weak when benchmarked against international best practice. A lack of data has impeded the policy debate and a significant gap in analysis remains a lack of empirical research into the life-cycle cost implications of increased building thermal efficiency, particularly for residential buildings. This paper applies an integrated thermal modeling, life cycle costing approach to an extensive sample of dominant house designs to investigate life cycle costs in a cool temperate climate, Melbourne Victoria. Empirical analysis provides new insights into lifetime costs and environmental savings for volume housing design options and identifies sensitive factors. Results suggest that the most cost-effective building design is always more energy efficient than the current energy code requirements, for the full time-horizon considered. Findings have significant policy implications, particularly in view of present debates which frequently present higher energy efficiency standards as prohibitive from a costs perspective.