In order to investigate the bond behavior of preplaced aggregate concrete-filled steel tube (CFT-PAC) columns and the difference of bond behavior between CFT-PAC columns and normal concrete-filled steel tube (CFT-NC) columns, a total of 11 columns were prepared and the push-out tests were conducted. The experimental parameters included the type of concrete (preplaced aggregate concrete and normal concrete), concrete strength (C40, C50 and C60), cross-section dimension (D = 219 mm, 299 mm and 351 mm) and the thickness of steel tube (t = 6 mm and 8 mm). The results indicated that the CTF-PAC columns had a similar load-slip curves with CFT-NC columns. The bond stresses of the CFT-PAC columns were higher than that of the PAC-NC columns at the same concrete strength. Increasing compressive strength of PAC increased the critical bond strength and bond strength of CFT-PAC columns. With an increase of the L/D ratio, both of the slip corresponding to peak load and bond strength of CFT-PAC columns exhibited an increasing trend. A rise in the D/t ratio led to a decrease in the bond stress of CFT-PAC columns and an increase in slip corresponding to the peak load of CFT-PAC columns. The proposed bond stress–slip relationship model considerably matched the bond stress–slip relationship of CFT-PAC columns.

In China, modern timber structure (MTS) has great market potential as an advanced architectural technology and corresponds to the direction of construction industrialization. However, the MTS building sector is still developing slowly, despite previous efforts by the Chinese government to promote its development. The development of the MTS building industry involves numerous stakeholders, and the complex relationships and behaviors of stakeholders are regarded as the reason for slow development. Therefore, this study aims to investigate the influencing factors related to MTS building from the stakeholders’ perspectives. The social network analysis (SNA) method was used to explore the key factors affecting MTS building development and analyze the interactions of influencing factors. Nine stakeholders were identified, and 23 influencing factors associated with these stakeholders were determined based on a literature review, questionnaire survey and interviews with specialists. The critical factors were government policy, the public’s understanding and acceptance, market positioning and development cost. In addition, the relationships of designer, prefabricated component manufacturer, and construction enterprise were very close. Based on the findings, corresponding countermeasures were put forward, including policy incentives and support expansion, technical specification system improvements, public awareness reinforcement, and the strengthening of personnel training, etc. This paper contributes to the developmental improvement of the MTS building sector in China.

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