Sustainable performance criteria for construction method selection in concrete buildings

The use of prefabrication offers significant advantages, yet appropriate criteria for applicability assessments to a given building have been found to be deficient. Decisions to use prefabrication are still largely based on anecdotal evidence or simply cost-based evaluation when comparing various construction methods. Holistic criteria are needed to assist with the selection of an appropriate construction method in concrete buildings during early project stages. Following a thorough literature review and comprehensive comparisons between prefabrication and on-site construction method, a total of 33 sustainable performance criteria (SPC) based on the triple bottom line and the requirements of different project stakeholders were identified. A survey of U.S. experienced practitioners including clients/developers, engineers, contractors, and precast concrete manufacturers was conducted to capture their perceptions on the importance of the criteria. The ranking analysis of survey results shows that social awareness and environmental concerns were considered as increasingly important in construction method selections. Factor analysis reveals that these SPCs can be grouped into seven dimensions, namely, economic factors: “long-term cost,” “constructability,” “quality,” and “first cost”; social factors: “impact on health and community,” “architectural impact”; and environmental factor: “environmental impact.” The resultant list of SPCs provides team members a new way to select a construction method, thereby facilitating the sustainable development of built environment.     

基于 MILP 算法的预制混凝土构件生产调度优化模型研究

伴随着装配式建筑的迅猛发展,预制混凝土构件的种类和数量不断增多,导致预制构件生产调度越来越复杂。以往研究大多忽略了加班在生产调度中的作用,相关模型无法通过安排工人加班来避免预制构件延期交付,使得其生产调度缺乏足够的灵活性。通过分析预制混凝土构件生产流程的特点,运用混合整数线性规划（Mixed Integer Linear Programming,MILP）算法,建立了预制混凝土构件生产调度优化模型。模型旨在通过合理安排构件生产顺序和工人加班时间,在满足订单要求的前提下,缩短构件在生产线上的等待时间和机器空闲时间,提高预制工厂的生产效率,并通过案例对比,验证了 MILP 算法对提高生产效率的有效性和可行性。     

大跨径混凝土拱桥拱上立柱接头施工质量控制

阐述了广西柳州市三江县中山大桥拱上立柱预制与现浇接头施工,介绍了接头模式、预制及现浇立柱端头处理、接头对接、接头混凝土施工控制要点,结合实际提出了对缺陷处理的措施,从而为实际工程施工积累经验。     

装配式混凝土建筑降碳贡献及主要影响因素分析

在研判国内装配式建筑发展现状的基础上,通过对装配式混凝土建筑碳排放案例的分析,探讨装配式混凝土建筑能源结构特征和碳排放测算存在的问题,提出物化阶段单位面积碳排放量和节碳量建议值,得出装配式混凝土建筑降碳贡献的影响因素,包括产业链成熟程度、规划设计和施工水平,以及运维拆除阶段的减碳意识和理念。从制度保障、规划设计、构件的预制运输、现场装配、运维和拆除等方面提出装配式建筑减排措施。     

基于改进FMEA法的装配式混凝土建筑建造质量风险评价

为了有效分析装配式混凝土建筑关键建造质量风险因素，提高相关方质量管理水平，对建造质量风险因素进行收 集归纳，建立装配式混凝土建筑建造质量风险评价指标体系，提出基于模糊 TOPSIS 和变权法改进的 FMEA 风险评价模型。 考虑装配式混凝建筑风险指标评价要素状态值的多变性，将惩罚型变权法引入评价要素客观权重确定中，建立各风险指标 评价要素的加权规范化矩阵，再利用 TOPSIS 逼近理想解的原理进行风险排序，得到风险优先等级，并结合实例验证该方 法的可行性和可操作性，从而为装配式混凝土建造质量风险管理提供一种新思路。     

北京射击馆预制清水混凝土外挂板施工技术

北京射击馆为2008年北京奥运会射击比赛用馆.以北京射击馆为例,介绍了预制无装饰清水混凝土外挂板的设计、预制和安装技术.工程施工前,对预制清水混凝土外挂板的制作、模板、钢筋骨架等制定了验收标准.根据外墙各部位尺寸、门窗位置,对板块尺寸、细部构造进行了深化设计;同时采取合理的配合比、原材料、预制方法和养护方法确保了混凝土颜色、表面观感、质量符合要求.安装过程中通过精确的测量放线确定外挂板的安装位置,从下向上依次逐层安装顺序完成了预制板的安装工作.     

复建超高层建筑的混凝土运输研究

以广州城际中心工程为例,介绍了已局部建成运营的超高层建筑在后期复建过程中,混凝土输送方式的选择以及在已建成运营楼层区域内混凝土输送管道的布置.实践证明,所述的混凝土运输方案有较好的可行性,可为同类型工程提供参考和经验借鉴.     

Towards adoption of prefabrication in construction

There is an urgent issue on huge quantities of wastage generation in construction. There should not be lack of environmental support from construction stakeholders. The current implementation of prefabrication seems unable to provide satisfactory results to the construction industry. This paper provides a feasibility analysis in adopting prefabrication in construction activities. Advantages, hindrances and future development on prefabrication's applications are provided based on a questionnaire survey. The suitability in adopting prefabrication of various project types is also examined. Furthermore, a financial analysis is also investigated by a local case study. It found that wastage generation can reduce up to 100% after adopting prefabrication, in which up to 84.7% can be saved on wastage reduction.     

装配式建筑施工阶段碳排放测算研究

根据碳排放系数法构建模型,结合工程量清单对装配式建筑施工阶段的碳排放进行测算, 探讨预制率对施工阶段碳排放的影响, 深入探究工程造价、总建筑面积与碳排放总量的关系。以漳州某住宅楼为例, 探讨施工阶段碳排放的排放规律并提出减排路径。 结果表明: 施工阶段的碳排放主要来自一般土建工程;单位面积的碳排放在 671 kgCO2/m2左右波动,单位造价的碳排放在 2749.33 kgCO2/万元左右波动; 混凝土工程和钢筋工程的碳排放随着预制率的升高而增加; 碳排放总量与工程造价、建筑面积存在显著的线性关系。     

装配式混凝土建筑发展的策略选择

当前我国逐步推广和普及装配式建筑，越来越多的龙头开发企业参与到装配式建筑的研究和项目开发中。简要总结外部环境对发展建筑工业化的推动作用，重点以技术—产业发展理论从内因分析建筑产业技术革新对建筑工业化的推动，以目前我国处于建筑工业化发展初步阶段，开发装配式混凝土建筑为例，以政府和开发商作为两大参与主体，采用动态博弈的方法，探讨双方各自采取何种策略达到帕累托最优。考虑当前不同预制率下的成本，探讨开发商之间对于不同预制率的策略选择。     

基于熵权法的绿色建筑项目管理绩效可拓评价

为确保绿色建筑得到进一步发展,需对其项目管理水平进行科学合理评价。将熵权法和可拓学理论引用到绿色建筑项目管理绩效评价体系中,采用熵权法确定指标权重,在给出关联函数及绩效评定等级的基础上,构建绿色建筑项目管理绩效可拓评价模型。通过计算各评价指标关于绩效测度的关联程度,确定各指标及总体项目管理绩效水平所处的等级。通过算例表明:该方法在绿色建筑项目管理绩效评价中具有较好的适用性。     

基于霍尔三维结构的装配式建筑EPC 总承包模式研究

针对装配式建筑 EPC 模式下参与方多、管理难度大等特点,结合装配式建筑和 EPC 工程总承包模式的特点,以及BIM 技术在工程中的相关应用,通过引入霍尔三维结构,从时间维、逻辑维、知识维 3 个维度研究了装配式建筑 EPC 总承包管理模式,通过建立时间维和逻辑维所在平面的相关活动矩阵,展示了装配式建筑 EPC 工程总承包模式下某一状态点的具体活动内容,并以建造施工阶段为例,论证了该方法的适用性,同时构造了基于霍尔三维结构的装配式建筑 EPC 模式运行模型,为管理者提供了一种分析工具。     

清水混凝土幕墙设计与施工技术

大连软件园9号楼为国内首例采用清水混凝土幕墙的建筑物,通过对清水混凝土挂板的优化设计,采用工厂预制和现场安装清水混凝土挂板作装饰外墙,具有施工质量好、速度快的优势,发展前景良好。     

Toward an economic design of reinforced concrete structures against progressive collapse

A three-dimensional discrete crack model based on the Applied Element Method is used to perform economic design for reinforced concrete structures against progressive collapse. The model adopts fully nonlinear path-dependent constitutive models for concrete and reinforcing bars. The model applies a dynamic solver in which post-failure behavior, element separation, falling and collision are predicted. First, the model is used to study the behavior of multi-story reinforced concrete buildings designed in a traditional manner according to the ACI 318-08 and subjected to accidental removal of one or two central columns at the ground level. In an iterative way, the model is then used to investigate a safe design against progressive collapse for such extreme loading case. Based on the analytical results of the AEM, it can be concluded that the collapse of only one column would not lead to any progressive collapse of the studied reinforced concrete structure. However, the collapse of more than one column may lead to a progressive collapse of a considerable part of it. It is concluded also that the AEM could be successfully used as an analytical tool to suggest economical designs that are safe against progressive collapse of reinforced concrete structures.     

功能型聚羧酸外加剂在混凝土预制构件中的应用

建设施工使用的混凝土预制构件产品种类资源十分丰富,常见的有在地铁工程、西气东输工程等隧道施工中高精度钢筋混凝土盾构管片的使用,在城市桥梁建设工程中预制拼装节段梁的使用,在高速铁路施工过程中预制清水混凝土饰面板的使用等。随着建筑质量需求的逐渐提升,混凝土预制构件的质量已经成为建筑领域备受关心的问题。     

The Use of Glued-in Rods for the Reinfororcement of Timber Structures in European Countries

The woody structural elements represent a significant portion of old works and historical buildings,and the need for retrofit and strengthening them increases.Glued-in rods are an efficient way of providing stiff,high-capacity connections in timber structures.Those flexible joint systems have the advantages of high load transition,appropriate behavior in case of fire,easy application combined with a high level of prefabrication for fast installation.Besides,the aesthetic appearance of the finished joint also plays an important role.Many experiments were undertaken on this subject in Europe,but a common database about the designing instructions of glued-in rods was never encouraged.This paper aims at summarizing the different factors that can affect repairs made with glued-in rods and their influence on said repairs.     

The evolution of prefabricated residential building systems in Hong Kong: A review of the public and the private sector

Prefabricated building components have been adopted in Hong Kong for over two decades for high-rise buildings. In the public sector, prefabrication together with standard modular design was introduced in the Housing Authority's public housing projects in the mid-1980s. Over the years, precasting techniques have significantly evolved in public housing projects. In contrast, prefabrication has only recently been adopted in the private sector. The aim of this paper is to examine the evolution of precasting technology in high-rise residential developments in Hong Kong, and then explore the technological influences in both sectors. A database of 179 prefabricated residential buildings was developed and detailed case studies of five residential developments were conducted. The findings revealed that a greater extent of prefabrication use over the years, in terms of precasting percentage by volume and types of precast elements utilised. Major prefabrication innovations, in both sectors, influenced the technological advancement in prefabrication in Hong Kong.     

基于BIM 的装配式建筑工程量清单构建研究

BIM 作为国际主流的信息构建模型,其与装配式建筑具有先天协调性。以装配式混凝土建筑为对象,基于模块化理论和BIM 的标准?精度要求,将BIM 标准?装配式建筑消耗量定额?现行工程量清单规范进行对比,找出3 种不同情况下的处理方式,从而建立了基于BIM 的工程分解结构。从项目编码、项目名称、项目特征、计量规则和计量单位5 个方面建立了不同结构层级所需要表达的工程量内容。对BIM 在我国装配式建筑造价管理的应用和装配式建筑工程量清单的后续深入研究具有一定借鉴意义。     

Life cycle design and prefabrication in buildings: A review and case studies in Hong Kong

Prefabrication has been increasingly used in buildings. It is recognised as a solution to reduce waste arising during design and construction phases. However, there is little emphasis on life cycle design issues for prefabricated buildings located in dense high-rise building environments. The purpose of this paper is to review the application and identify benefits and impediments of design for deconstruction and Industrialised, Flexible and Demountable building systems when applied to precast concrete construction. The paper presents the results of a comprehensive literature review, and two case studies of recently completed institutional buildings using prefabrication. The literature review shows that, so far, design for deconstruction is not a common practice in the building industry. The case studies showed some limitations such as the dense urban environment conditions and limited site area. The promotion of a closed-loop material cycle is critical to contribute to sustainability thus minimising CO₂ emissions, natural resources consumption.     

清水预制挂板在虹桥机场西航站楼中的应用

上海虹桥国际机场西航站楼采用清水混凝土外墙挂板技术。本文介绍了预制清水混凝土外墙挂板的设计、预制、施工和安装技术。工程施工前，对预制清水混凝土外墙挂板的制作、模板、钢筋骨架等进行了深化、精细的设计，同时采用合理的配合比、原材料、预制方法和养护方法确保了混凝土颜色、表面观感、质量符合要求。