Construction resource/method factors influencing productivity for high rise concrete construction

Research among European countries had confirmed variance in productivity rates ascribed by construction planning engineers for identical operations. Similar differences in planned construction resource/method factors also had been identified. It is hypothesized that such variance may be due to differences in contractor preference, resulting from socio-economic and corporate objective impacts. Analysis of variance and correlation tests are used to examine this hypothesis on data obtained from French, German and UK contractors. Numerous construction resource/method factors are tested for their impact on mean productivity rates for principal high rise in situ concrete construction operations. Significant productivity rate variations are identified for reinforcement fixing and formwork erection, while variance in concrete placing productivity rates are not found to be dependent upon construction resource/method factors. Contractors seeking to improve productivity might wish to consider solutions for construction resource/method decisions that have been found herein to be related to higher productivity rates and (in some cases) lower costs.     

高支模板支撑系统施工中问题分析及措施

高大模板支撑系统施工中的问题,严重影响了建筑质量和生产安全,本文从汇集的多个项目中发生的高大模板支撑系统问题入手,并以多个工程实例,介绍问题产生的原因和防治措施。     

Planning gang formwork operations for building construction using simulations

Concrete formwork is a labor-intensive and time-consuming operation. Many modular formwork systems have been developed to automate the process. Such systems improve the productivity as well as the cost-effectiveness of the operation. However, proper planning for the form reuse schemes in the design as well as the construction phases of a building, including resource allocations (modular form sets, cranes, workers, etc.), and the construction sequence, is vital for ensuring a successful use of modular formwork systems. Computer process simulation techniques are employed in this research for the study of different form reuse schemes to use gang forming systems in building construction. Five form reuse schemes are identified. The CYCLONE modeling methodology is employed to develop computer models for each of them. MicroCYCLONE simulations and sensitivity analyses of the schemes, using different numbers of form sets, cranes, and labor crews, are then conducted for a real case to assess their impact on the productivity as well as the cost-effectiveness of the operation. The objective is to better understand the characteristics of different form reuse schemes and, in turn, to produce better plans for gang forming construction. Thus, the application of modular formwork systems in building construction can be facilitated.     

Assessing the capability of construction processes to realize building designs

The capability of processes should be assessed during their development. If assessment reveals that a process is not capable of meeting design requirements, that process should be improved until reassessment indicates that it is capable. This proactive approach can radically reduce non-conformances. Existing methods of assessment depend upon the sampling of process data. Such methods are well-established and well-documented. They provide the foundation for statistical process control (SPC) and can be applied to most processes including those used in the construction of buildings. However, there are several reasons why sampling data to assess construction process capability can be extremely difficult. In this paper, the limitations of existing assessment methods are outlined. Then, a new assessment method is introduced and results from a preliminary field study are reported. Next, the key features of the new method are discussed. In conclusion, guidelines for its successful introduction are provided.     

Selection of mobile cranes for building construction projects

The complicated process of selecting cranes for construction projects can be divided roughly into two main phases: (1) a general decision on the type of crane, mobile or tower; and (2) selection of the particular model according to the required size and technical specification. Several determinants of this second phase of the selection process in a typical mobile crane culture were investigated through on-site interviews with representatives of major construction companies. Factors affecting mobile crane selection were identified, classified, and rated according to their degree of influence. The involvement in equipment planning and crane selection was characterized with regard to project stages and planning parties. The findings were analysed with a view to the changing participation level of each party throughout project life. The conclusions of the study portray a picture that is different from the common assumptions about mobile crane selection, with respect to both influencing factors and the process itself. The study underlines the weight of non-project-specific factors, and shows that equipment planning is not merely a one-time technical exercise executed by a planner, but rather a process carried out throughout project life by a joint effort of several parties.     

Modeling construction time in Spanish building projects

The literature states that project duration is affected by various scope factors. Using 168 building projects carried out in Spain, this paper uses the multiple regression analysis to develop a forecast model that allows estimating project duration of new builds. The proposed model uses project type, gross floor area (GFA), the cost/GFA relationship and number of floors as predictor variables. The research identified the logarithmic form of construction speed as the most appropriate response variable. GFA has greater influence than cost on project duration but both factors are necessary to achieve a forecast model with the highest accuracy. We developed an analysis to verify the stability of forecasted values and showed how a model with high values of fit and accuracy may display an anomalous behavior in the forecasted values. The sensitivity of the proposed forecast model was also analyzed versus the variability of construction costs.     

浅谈超高层写字楼供配电系统设计

通过超高层写字楼设计的实例,从负荷等级及容量、变电所设计选址、供配电系统、谐波抑制、自备应急电源选型、消防泵房配电、电缆及导线的选用原则等方面,介绍了新建超高层写字楼的供配电系统设计。     

注重房屋建筑可持续发展 推进节约型社会建设

本文针对我国资源能源相对不足、环境承载能力较弱的基本国情,就房屋建筑过程中如何节约能源资源,实现可持续发展,提出相关的建议。     

高层建筑消防供配电设计

本文通过分析我国目前高层民用建筑几种消防供配电设计方案,并结合规范与工程实际情况,对目前高层建筑供配电设计存在的问题进行探讨,并提出相应的解决方案。     

Construction delay analysis techniques

Construction projects continue to suffer delays. Things go wrong and the project's completion date gets pushed back, with someone to be blamed for it. In practice, attempts are made to identify the causes of delays and schedules are modified to incorporate revised duration and new project time. The analysis itself is usually complex and can be aided by a computerized approach. This paper discusses different delay analysis techniques that are currently used by practitioners in the construction industry. It also discusses a proposed new delay analysis technique called the Isolated Delay Type (IDT). These techniques were tested against a case example and their strengths and weaknesses highlighted. The new technique can be used as a standalone module for delay analysis or could be incorporated within a computer system for construction delay analysis and claims preparation called Computerized Delay Claims Analysis (CDCA) that integrates different software including an expert system and management software such as scheduling and a database or spreadsheet.     

施工中的高层住宅楼室内火灾烟气传播分析

为了分析施工中的高层住宅楼室内发生火灾时大楼内的温度场和烟气扩散规律,应用火灾动力学软件对火灾场景进行模拟分析,获得了相应的温度场、烟气扩散规律和能见度数据,以供逃生救援参考。     

导轨式爬架在高层建筑施工中的应用

结合吕梁八一公寓安置楼工程外脚手架的应用经验,介绍了导轨式爬架的结构原理、安装使用等情况,实践证明该工程应用导轨式爬架不仅提高了安全可靠性,而且降低了施工成本,综合效益显著。     

大模板技术在高层建筑施工中的应用分析

高层建筑施工是近年来比较常见的一种建筑模式。随着高层建筑经验的积累和技术的不断革新,大模板的应用技术已经比较成熟了,但是在实际的施工中仍然存在一系列的问题,笔者主要对这些问题进行了论述,并提出了具体的解决办法,希望能够给技术人员一定的参考和借鉴。     

An object-oriented model for planning and control of housing construction

A practical object-oriented model for the planning and control of housing construction is presented that can generate efficient schedules and determine the time and cost performance of a housing project at three levels: (i) entire project, (ii) particular housing unit and (iii) an individual subcontractor. The model comprises five major components: (1) input module, (2) scheduling module, (3) database module, (4) control module and (5) reports module, and incorporates 18 classes that are designed to address the main requirements in planning and control of housing construction. The model is implemented as a user-friendly prototype software system using Visual C++ 6.0 and Microsoft Foundation Class (MFC). The prototype software is named ‘Residential Planner’, and runs in Windows 2000 and NT. An example of an application is analysed to illus8 trate the use of the developed model and demonstrate its practical features.     

高层建筑剪力墙结构滑模施工技术要点

通过某高层住宅剪力墙滑模施工的应用,从混凝土的质量控制、模板的滑升、出模强度控制、纠偏等几方面进行了探讨和研究,提出如果技术可靠、措施得当、管理到位,滑模工艺的快速高效可以得到充分的体现。     

Indonesian residential high rise buildings: A life cycle energy assessment

This study evaluates the effect of building envelopes on the life cycle energy consumption of high rise residential buildings in Jakarta, Indonesia. For high rise residential buildings, the enclosures contribute 10-50% of the total building cost, 14-17% of the total material mass and 20-30% of the total heat gain. The direct as well as indirect influence of the envelope materials plays an important role in the life cycle energy consumption of buildings. The initial embodied energy of typical double wall and single wall envelopes for high residential buildings is 79.5 GJ and 76.3 GJ, respectively. Over an assumed life span of 40 years, double walls have better energy performance than single walls, 283 GJ versus 480 GJ, respectively. Material selection, which depends not only on embodied energy but also thermal properties, should, therefore, play a crucial role during the design of buildings.     

福建省高海拔地区高大模板施工的控制要点

本文以周宁的高大模板工程项目为例,分析高大模板施工中大风及低温的影响因素,从而提出解决方法,对福建东北地区类似工程施工提供借鉴。     

高层建筑多层模板支撑体系安全性控制方法

针对高层建筑施工期模板支撑体系安全性控制,提出以支撑楼板安全为约束,通过调整施工周期、支模层数以及拆模时间等施工参数,使支撑楼板的安全性满足要求,在获得优化施工方案后根据模板支撑设计的高层建筑混凝土结构施工期安全性进行控制。     

高层建筑施工GPS测量的技术设计与应用

论述了高层建筑施工GPS网设计的依据，探讨了高层建筑施工GPS网的精度设计、图形设计和基准设计方法，还介绍了GPS技术应用于高层建筑施工的情况。