Re-engineering the tender code for construction works

The UK's NJCC Code of Procedure for Single Stage Selective Tendering (now withdrawn) and its successor, the CIB's Code of Practice for the Selection of Main Contractors are criticized in the light of decisions of the common law courts with regard to regulation of the tendering process. It is argued that a new ‘Tendering Code’ should be produced in the style and format of a contract document which reflects not only the statutory regulation imposed on public bodies, but common law decisions of the courts. The nature of this tendering contract is explained as a means of regulating the tendering process. Issues discussed are: dealing with errors and irregularities found in tenders; dealing with non-compliant tenders; dealing with tender withdrawal prior to its acceptance or rejection; making provisions as to time for submission of tenders and dealing with late tenders; making provision for submission of tender by fax or other electronic means; making provision for evaluation of tenders received; and imposing or negotiating reductions in price with tenderers prior to acceptance. The paper concludes that the common law obligations placed on the owner to treat all tenderers equally and fairly and to apply the tender conditions when evaluating tenders and awarding contracts seems to be good common sense and of commercial advantage, not only to the immediate parties concerned but also to the wider community.     

An industrial organization economic supply chain approach for the construction industry: a review

Understanding industries in terms of the concepts of chains, clusters and networks is becoming increasingly important in economies around the world. Supply chain management for an individual organization is an emerging field of research in the construction management discipline, but less attention has been devoted to investigating the nature of the construction supply chains and their industrial organizational economic environment. This selected review of construction and mainstream management supply chain literature is organized around four themes; distribution, production, strategic procurement management and industrial organization economics, and highlights the need to develop an industrial organization economic supply chain framework for construction. The merging of the supply chain concept with the industrial organization model as a methodology for understanding firm conduct and industry structure and performance is an important contribution to both construction supply chain and construction economic theory. Much of the industrial organization supply chain literature has tended to focus upon manufacturing industries, where typically firms are permanent organizations. This raises issues as to the differences between industries founded upon temporary compared with permanent organizations. There is potential for the development of an industrial organization methodology applicable to the project based industry. Ultimately industrial organization research seeks to have direct implications for industry performance and government policies.     

工程施工招标阶段工程造价控制之我见

分析工程施工招投标各个环节的工作内容,提出招投标各个环节的工程造价控制措施。     

Estimating the number of new and repeated bidders in construction auctions

The number of new bidders – bidders from whom there is no previous registered participation – is an important variable in most bid tender forecasting models, since the unknown competitive profile of the former strongly limits the predictive accuracy of the latter. Analogously, when a bidder considers entering a bid or when an auctioneer is handling a procurement auction, assessing the likely proportion of experienced bidders is considered an important aspect, as some strategic decisions or even the awarding criteria might differ. However, estimating the number of bidders in a future auction that have not submitted a single bid yet is difficult, since there is no data at all linking their potential participation, an essential requirement for the implementation of any forecasting or estimation method. A practical approach is derived for determining the expected proportion of new bidders to frequent bidders as a function of the population of potential bidders. A multinomial model useful for selective and Open tendering is proposed and its performance is validated with a dataset of actual construction auctions. Final remarks concern the valuable information provided by the model to an enduring unsolved bidding problem and the prospects for new research continuations.     

Analysis of the distribution of the number of bidders in construction contract auctions

The number of bidders, N, involved in a construction procurement auction is known to have an important effect on the value of the lowest bid and the mark-up applied by bidders. In practice, for example, it is important for a bidder to have a good estimate of N when bidding for a current contract. One approach, instigated by Friedman in 1956, is to make such an estimate by statistical analysis and modelling. Since then, however, finding a suitable model for N has been an enduring problem for researchers and, despite intensive research activity in the subsequent 30 years, little progress has been made, due principally to the absence of new ideas and perspectives. The debate is resumed by checking old assumptions, providing new evidence relating to concomitant variables and proposing a new model. In doing this and in order to ensure universality, a novel approach is developed and tested by using a unique set of 12 construction tender databases from four continents. This shows the new model provides a significant advancement on previous versions. Several new research questions are also posed and other approaches identified for future study.     

A framework of information visualization for multi-system construction

Modern buildings usually include multiple systems such as air-conditioning (AC), water supply and gas pipes, sanitary lines, telecommunication systems and security networks. Because these systems are highly interdependent, conventional methods for presenting information, typically a 3D model and a schedule, are insufficient to effectively manage and coordinate various experts working on a project. This research proposes a framework that enables engineers to explore and interact with the information visually. It includes four information views (temporal, hierarchical, relational and spatial), four interaction functions (information exploration, cross-highlighting, time controller, and information extraction) and two display layouts (matrix hardware layout and flexible software layout). A prototype system called Construction Dashboard was implemented following this framework. To validate the effectiveness of the proposed framework we conducted a user test (N = 30) using an example project involving four systems (power, AC, water and computer). Each user answered nine questions related to different management and coordination problems by employing both Construction Dashboard and the conventional method (3D model with a schedule). The results showed that the completion times, for each of the nine questions, to solve these questions are significantly faster when using Construction Dashboard. The success rates to obtain the correct answers are also significantly better in three of the nine questions.     

Three methods for verifying and validating the simulation of a construction operation

A simulation model must be verified to confirm that it describes correctly its intended real world process under study; moreover, the simulation results obtained must be a valid representation of the process. This study presents three activity-based white-box methods for assisting a user in verifying and validating construction simulations. The first method reports a simulation by listing all activities in the chronological order of their executions, so that a user can contrast the simulated progress against the actual progress in the real world. The second method summarizes the operating counts and mean durations of all activities over the simulated time period, to enable a user to evaluate whether all activities have been executed correctly during simulation. The third method generates an activity cycle report for any selected resource entity, so that a user can examine whether the entity is moving in the correct logical and chronological order during simulation. The three methods can be used jointly to debug a simulation model, so as to confirm that the simulation is correctly conducted and the obtained results are valid. The three methods are implemented in a simulation system in the form of corresponding reports. A concreting process is employed to illustrate these methods.     

A framework for rapid local area modeling for construction automation

Rapid 3D positioning and modeling in construction can be used to more effectively plan, visualize, and communicate operations before execution. It can also help to optimize equipment operations, significantly improve safety, and enhance a remote operator's spatial perception of the workspace. A new framework for rapid local area sensing and 3D modeling for better planning and control of construction equipment operation is described and demonstrated. By combining human-assisted graphical workspace modeling with pre-stored Computer-Aided Design (CAD) models and simple sensors (such as single-axis laser rangefinders and remote video cameras), modeling time can be significantly reduced while potentially increasing modeling accuracy.     

A survey of current cost estimating practices in the UK

The results are documented of an investigation into current cost estimating practices of contractors for construction projects. A questionnaire survey of contractors was undertaken, in which the respondents are classified into four groups based on their turnover namely: very small, small, medium and large firms. The survey indicates that contractors, irrespective of size, continue to undertake cost estimating predominantly for construction planning purposes, including the preparation of tenders and cost control of projects during the execution stage and, to a lesser extent, for construction project evaluation. Recent developments in cost estimating methods and tools that consider risks and variability in cost estimates, such as the use of range estimating and parametric estimating techniques, have not been adopted by contractors. The practice of cost estimating does not differ from conventional techniques based on the use of labour and material constants to obtain prices for bills of quantities items on an item by item basis. The study shows that the major causes of inaccuracy in cost estimating continue to be the lack of practical knowledge of the construction process by those responsible for the estimating function, insufficient time to prepare cost estimates, poor tender documentation and the wide variability of subcontractors' prices.     

The performance of contractors in Japan,the UK and the USA: a comparative evaluation of construction cost

Globalization of the world economy demands that performance comparisons are undertaken at an international level. A new research protocol has been developed for comparing contractor performance internationally by combining the appropriate characteristics of two established approaches in order to balance the requirements of comparability and representativeness. This new approach is used to reveal some important international performance characteristics among Japanese, UK and US contractors. Building costs in the UK, when adjusted for exchange rate fluctuations, are significantly higher than those in Japan and the USA. Furthermore, cost certainty and client satisfaction are higher in Japan than in the UK, but there is no significant difference between Japan and the USA. Disparities in cost performance between the three countries are believed to originate from differences in the relationships between contractors and clients and also in the construction process.     

地下车库地面施工质量控制

本文介绍了影响地下车库地面施工质量主要问题的调查和原因分析,及在某工程施工中采取的具体处理措施,取得一定的成效,为类似工程施工提供了参考。     

工程机械动力装置硬齿面行星轮系各齿轮齿数的确定

本文在满足硬齿面行星轮系传动比同心及装配条件的基础上，推导出硬齿面行星轮系内中心轮齿数Ｚ的计算公式，并将该计算式与配齿公式及邻接条件验算公式进行综合，设计出硬齿面行星轮系各轮齿数计算程序框图。     

工程机械齿轮传动的弹流动力润滑试验研究

介绍一种能直接测定齿面啮合过程中,弹流润滑状态参数的试验装置,并以工程机械用齿轮为实例,阐述了它的基本测试原理和方法。这为进一步完善齿轮弹流润滑的测试技术,促进工程机械用齿轮润滑机理的研究提供了重要依据。     

浅谈建设项目施工阶段造价控制

造价控制是施工管理的重要环节,本文主要从优化施工组织设计等六个方面,对如何进行施工阶段建设项目的造价控制进行了阐述。     

A new approach for thin-walled member analysis in the framework of GBT

A new approach is illustrated for the cross-sectional analysis to be performed in the context of the Generalised Beam Theory (GBT). The novelty relies in formulating the problem in the spirit of Kantorovich’s semi-variational method, namely using the dynamic modes of an unconstrained planar frame as in-plane deformation modes. Warping is then evaluated from the post-processing of these in-plane modes, thus reversing the strategy of the classical GBT procedure. The new procedure does not require several steps of the classical algorithm for the determination of the conventional modes, in which bending, shear and local modes are evaluated separately, and is applicable indifferently to open, partially-closed and closed sections. The efficiency and ease of use of the method are outlined by means of two examples, aimed to describe the linear–elastic behaviour of thin-walled members.     

A century of innovation in the Dutch construction industry

In recent years, the number of publications on innovation in the construction industry has increased. Many of these documents address qualitative issues, e.g. policies for innovation and present case studies. A more quantitative approach is taken in this paper, which is the continuation of a previous study. It focuses on main types and sources of innovation in the construction industry, and includes an analysis of 55 years of publications in two leading Dutch professional journals. The results show a recent increase in innovation, with two‐thirds of innovations coming out of supplying industries. Construction companies contribute mainly in process innovations. Innovation in construction remains to be technology‐ rather than market‐driven. Regulations have a surprising impact, as over one‐third of all counted new innovations are related to new regulations.