Dariusz Wanatowski

Empirical Study of BIM Implementation–Based Perceptions among Chinese Practitioners

The global movement of building information modeling (BIM) is spreading the implementation of BIM from developed countries to other developing countries. Practitioners’ perceptions of BIM implementation in these developing countries, such as China, a giant building market that is increasing the application of BIM in the industry, have not been thoroughly understood. This research used the questionnaire method to survey 94 randomly recruited Chinese BIM professionals to investigate BIM practice and its related perceptions. Reductions in design errors and resultant construction rework were considered the top benefits of using BIM. The most important factor in achieving BIM value was noted as interoperability among various BIM tools. A comprehensive evaluation of BIM at the company level was considered a major difficulty of implementing BIM. The owner was considered the party that received the most benefits from BIM. Subgroup differences based on two major categories (i.e., participants’ profession and BIM proficiency level) were analyzed in the survey sections related to BIM implementation. Statistical analysis revealed that, generally, neither the profession nor BIM proficiency level affected participants’ perceptions of the benefits, factors, challenges, or benefited parties in BIM implementation.

BIM Investment, Returns, and Risks in China’s AEC Industries

Building Information Modeling, or BIM, the emerging digital technology, is undergoing increasing application in developing countries including China. Both the governmental policy and industry motivation have indicated that BIM is becoming the mainstream innovation in Chinas construction industry. Nevertheless, one major concern lies in the uncertainty of BIM investment for AEC firms. Specifically, AEC firms should have the knowledge of what areas BIM investment could focus on (e.g., BIM software), what are the expected returns from BIM investment, how to enhance the returns from BIM usage, and what are the risks in implementing BIM. This study adopts a questionnaire survey-based approach to address these BIM application and risk related concerns in China. BIM practitioners from multiple AEC fields and different experience levels were recruited as the survey sample. It was found from the questionnaire survey that both internal and external collaboration should be the BIM investment priority, together with the interoperability among multiple BIM software tools. Improved multiparty communication and understanding was the highest recognized return from BIM investment. Survey participants had a high expectation of BIM application in green building projects. Subgroup analysis conveyed the information that gaining BIM practical experience would provide professionals with more confidence on returns from BIM adoption in enhancing communication and understanding. Compared to survey participants from other professions, architects tended to have more conservative views on BIMs impact on marketing their work, project planning, and recruiting/retaining employees. The findings from this empirical study provide an overview of BIM investment, return, and implementation-related risks for AEC professionals at different stages or levels of BIM practice, as well as suggestions for relevant public authorities when developing BIM guidelines (e.g., BIM applications in prefabrication construction). As an extension of existing BIM implementation related studies in developed countries, this study provides insights of BIM practical experience and associated risks in China adopting a holistic approach by summarizing the perceptions from AEC professionals across disciplines and experience levels. The knowledge gained from this study could be further applied in other developing countries where the application of information technology is gaining the growth in AEC projects.

Backcalculation of pavements incorporating Grouted Macadam technology

Applying cement grout with a high compressive strength to a porous layer made of asphalt concrete results in a pavement with the properties of an intermediate type that combines the characteristics of both flexible and rigid pavements. This solution is known as Grouted Macadam (GM). Despite a wide range of test results on the GM pavements presented in the literature, there are very few advanced modelling solutions formulated in the scope of bearing capacity measured in situ be means of a Falling Weight Deflectometer. This paper turns out that the seemingly small frequency of loading (≈20 Hz) generated during pavement deflection measurements using a Falling Weight Deflectometer-like device, has a significant impact on the backcalculation results of GM pavements. The study shows that, introducing frequency normalisation of both the pavement loading and vertical displacements to the backcalculation, can limit the statistical scatter of backcalculation results by close to a half in comparison with the classical backcalculation procedure.

Implementation of Advanced Constitutive Models for the Prediction of Surface Subsidence After Underground Mineral Extraction

Surface subsidence is a typical problem for any underground mineral extraction. In order to choose an appropriate method of extraction, predict damage to infrastructure and other unwanted consequences of surface subsidence, it is necessary to model the surface settlement. Previous research has shown that the conventional constitutive models, which are built into commercial software, encounter considerable difficulties when attempting to predict subsidence troughs. The troughs should be modelled deeper and narrower.

Numerical Simulation of Surface Subsidence After the Collapse of a Mine

Surface subsidence is a concern for many underground mining activities. If not predicted, this phenomenon can cause severe infrastructure damage. In this paper, a computer model is used to predict surface subsidence after the controlled collapse of a coal mine at Naburn in North Yorkshire, England. Scarcity of data on the characteristics of deep underground distressed and caved zones around coal mining excavations makes the numerical prediction of mining-induced subsidence very difficult. The authors derive appropriate input parameters for the numerical model using available borehole data with all necessary justifications provided. Simulations are performed using the commercial software FLAC3D. Different constitutive models, such as Mohr-Coulomb, modified Hoek-Brown, strain-softening, double-yield, and modified Cam-clay are used to obtain surface subsidence profiles, which are compared against measurements taken at the site. Special attention is given to numerically simulating processes involved in the underground movements. It is shown that none of the models listed above can reasonably predict the surface subsidence profile.

Effect of Material Stiffness Variation on Shakedown Solutions of Soils Under Moving Loads

Shakedown limits of pavements and railway foundations can be calculated based on shakedown theorems. These values can be used to guide the thickness designs of pavement and railway constructions considering material plastic properties. However, most existing shakedown analyses were carried out by assuming a unique stiffness value for each material. This paper mainly concentrates on the influence of stiffness variation on the shakedown limits of pavements and railway foundations under moving loads. Finite element models as well as a user-defined material subroutine UMAT are first developed to obtain the elastic responses of soils considering a linearly increasing stiffness modulus with depth. Then, based on the lower-bound shakedown theorem, shakedown solutions are obtained by searching for the most critical self-equilibrated residual stress field. It is found that for a single-layered structure, the rise of a stiffness changing ratio will give a larger shakedown limit; and the increase is more pronounced when the friction angle is relatively high. For multi-layered pavement and railway systems, neglecting the stiffness variation may overestimate the capacity of the structures.

The influence of frequency normalisation of FWD pavement measurements on backcalculated values of stiffness moduli

Backcalculation is commonly used for determining stiffness moduli of pavement courses and its subgrade based on in situ deflection tests. However, the in situ test results are dependent on the frequency domain, which in turn has a significant influence on the backcalculation results. In this paper, one of the methods for normalising the frequency of load and displacement functions obtained from a dynamic impulse generated by a falling weight deflectometer (FWD) test is verified. The assessment of the method is carried out based on backcalculation results of pavement deflection tests induced by both the dynamic and static loads and an independent numerical experiment. The analysis carried out in this paper shows that the normalisation of vertical displacements and pavement loads to the values corresponding to the frequency of 0 Hz improves the accuracy of the backcalculation results. It can be concluded that the frequency normalisation procedure is an effective way for standardising the boundary conditions in the backcalculation of flexible pavements.