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The pre-tender estimation process is still a hazy and inaccurate process, despite it has been practiced over decades, especially in Malaysia. The methods evolved over time largely depend on the amount of information available at the time of estimation. More often than not, the estimate produced during the pre-tender stage is far more than the tender cost of the project and sometimes, it is perilously underestimated and caused major problems to the client in the monetary planning. The purpose of this paper is to determine the most influential factors on the deviation of pre-tender cost estimation in Malaysia by conducting a survey.

Fuzzy logic, combined with artificial neural network method (fuzzy neural network) was then used to develop an estimating model to aid the pre-tender estimation process.

The results showed that the model is able to shift the cost estimation toward accuracy. This model can be used to improve the pre-tender estimation accuracy, enabling the client to take the necessary early measures in preparing the funding for a building project in Malaysia.

To the authors’ knowledge, this is the first study on tender price estimation standardization for a construction project in Malaysia. In addition, the authors have used factors from literature for the model, which shows the thoroughness of the developed model. Thus, the findings and the model developed in this study should be able to assist contractors in coming out with a more accurate tender price estimation.

Most of the previous studies conducted on the subject of subcontractors often focussed on a single phase of subcontracting practice; either on registration, selection of subcontractors or on monitoring of subcontractors without much integration to other different phases involved. Thus, on the basis of that reason, the purpose of this paper is to link the gap between different phases of subcontracting practice. This study also attempts to explore the relationships between the key criteria used by general contractors in selecting subcontractors before job awarding (CSSC) and the key criteria used for monitoring subcontractors during construction work (CMSC); which will then include an investigation of the effects these criteria have on project performance (PP).

The data obtained from a total of 162 G7 contractors in Malaysia were analysed. The interrelationships between the criteria and the effects of these criteria on PP were investigated simultaneously by employing a single model based on structural equation modelling (SEM) method.

The final model has discovered four major criteria that are often considered during the selection of subcontractors namely, “communication”, “relationship”, “general obligation” and “resource management” of a subcontractor. Meanwhile, the major criteria that are referred to in the monitoring of subcontractors are “workmanship”, “awareness of environment, health and safety” and “communication and relationship”. The four CSSC were found to be interrelated among themselves and affected CMSC during the construction stage. The research also revealed that the criteria used in monitoring subcontractor do affect the performance of a project. Thus, based on the result of this investigation, the monitoring of subcontractor is essential in discerning the performance level of a project.

An established SEM improves a subcontracting practice by creating platforms for CSSC, CMSC and PP to influence each other. With the gap between selection and monitoring subcontractors are filled, then the prediction of the subcontractors’ performance can be made possible.

The purpose of this paper is to introduce the numerical methods in tunnel engineering and their capabilities to indicate the fracture and failure in all kinds of tunneling methods such as New Austrian Tunneling Method, tunnel boring machine and cut‐cover. An essential definition of numerical modeling of tunnels to determine the interaction between geo‐material (soil and rock) surrounding the tunnel structure is discussed.

Tunnel geo‐material (soil and rock) interaction requires advanced constitutive models for the numerical simulation of linear, nonlinear, time‐dependent, anisotropic, isotropic, homogenous and nonhomogeneous behaviors. The numerical models discussed in this paper are developed in finite element method (FEM), finite deference method (FDM), boundary element method and discrete element method and these tools are used to illustrate the behavior of tunnel structure deformation under different loads and in complicated conditions. The disadvantage of this method is the tunnel lining assumed an independent structure under fixed load which is unable to model soil‐lining interaction. Predicting the effect of all natural factors on tunnels is the most difficult method. The above‐mentioned numerical methods are very simple and quick to use and the results are conservative and practical for users. One of the most significant advantages of the numerical method is in predicting the critical area surrounding the tunnel and the tunnel structure before making the tunnel construction due to different loads.

Numerical modeling is used as control method in reducing the risk of tunnel construction failures. Since some factors such as settlement and deformation are not completely predictable in rock and soil surrounding the tunnel, using numerical modeling is a very economical and capable method in predicting the behavior of tunnel structures in various complicated conditions of loading. Another benefit of using numerical simulation is in the colorful illustrations predicting the tunnel behavior before, during and after construction and operation.

There are not many conducted studies using numerical models to tunnel structures that estimate the critical zones. As some of the methods available have limitation in simulating and modeling the whole tunnel design factors, numerical modeling seems to be the best option, because it is fast, economical, accurate and more interesting in predicating critical zones in tunnel. However, what softwares predict are not always the same as real ground nature conditions in which there is tunnel.