Purpose-The purpose of this paper is to investigate the commercial aspect of "green" building construction and whether increased investment costs are profitable taking the reduction in operating costs into account. The investment viability is approached by comparing investment in conventional and "green" residential building, particularly passive houses, using real construction and post-occupancy conditions. Design/methodology/approach-The key data were obtained by surveys and personal interviews. The first survey was directed to the companies which had experience of building low-energy housing and the second survey to housing companies that actively manage operation of low-energy houses. Findings-Findings indicate that low-energy buildings are considered an interesting and sound business opportunity, and investment analysis indicates that low-energy houses (particularly passive houses) can be more attractive investments than conventional residential buildings. The long-term strategy of building low-energy buildings can give competitive advantages. The government initiative and the construction regulations are found to be necessary in eliminating the initial barrier to energy-efficient projects and achieving long-term environmental goals. Originality/value-This paper provides insights into the investment decisions and contributes to the understanding of the construction, operation and profitability of energy-efficient residential buildings.

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To enable the study of the sheet pile-soil interaction during driving, it was essential to have a record of the sheet pile vibrations as well as the vibrations at depth in the surrounding soil. In this paper, an instrumentation system for vibration analysis during vibratory sheet pile driving was presented. The instrumentation system was used in a full-scale field test where vibrations were measured on the sheet pile as well as at depth in the ground. The new instrumentation system and the field test were thoroughly described. As a sheet pile was driven into the ground, vibrations were transferred both at the toe and along the shaft. Whether it was the toe or the shaft that created the largest contribution to vibrations in the ground is debated in literature. Results from the field test were presented in order to investigate the effect of the position of the sheet pile toe on the ground vibrations at depth. It was shown that, within a distance of about 1.6 m from the driven sheet pile, the ground vibrations at depth were affected by the passing of the sheet pile toe. The current field test also indicated that the toe contributed to more ground vibrations than the shaft.

Vibrations due to pile and sheet pile driving are known to cause discomfort for people, as well as damage to nearby buildings and structures. To enable prediction of ground vibration levels it is important to acknowledge the wave patterns induced in the ground to correctly determine which attenuation model to adopt. This paper presents wave patterns in the ground due to vibratory sheet pile driving based on field measurements from three case studies. The results show different wave patterns in the ground. At the ground surface the wave patterns are elliptical, resembling Rayleigh waves. At depth in the soil the wave patterns are instead strongly polarized in different directions, indicating the presence of P-and S-waves. Moreover, wave patterns tend to become more irregular with increasing distance from the source. This paper contributes to an improved understanding of wave patterns in the ground during vibratory sheet pile driving, forming a platform for the development of a reliable prediction model.