The increasing excavated soil from construction projects has become a big problem in the sustainable development of megacities worldwide. Even though excavated soil management concerns are receiving increased attention, low rates of excavated soil recycling remain a barrier to the continuous improvement of the construction industry. Nowadays, Building Information Modeling (BIM) technology has gained popularity for construction and demolition (C&D) waste management purposes. However, few studies and cases of recycling excavated soil using BIM technology have been found. This paper gives a BIM-GIS-IoT-based excavated soil recycling system to effectively integrate BIM and Internet of Things (IoT) technologies into a geographic information system (GIS) to achieve scientific and reasonable recycling for excavated soil. The system mentioned above could collaboratively manage information from the government, developers, construction enterprises, transportation companies, and recycling facilities to meet the requirement for the specific communication, analysis, decision-making, and recycling plan preparation of the excavation project. In addition, it provides a systematic method and applies relevant information technology required to recycle the excavated soil effectively in the excavation project. The system is intended to provide a fundamental digital construction model for excavated soil recycling, regardless of whether it is invoked by the existing application software or a program tailored to the demands of a specific organization or stakeholders. It makes excellent use of the rich information stored in digital information models, may create a mapping to the input data required by the application, or automatically convert the basic model to facilitate the specific analysis. This system can not only serve as an excavation project simulation tool before construction, but also serve as a tool to recycle the excavated soil and cost evaluation. The developed model is applied via case studies within an excavation project. Different plans are described and compared in detail in several aspects of the schedule, revenue, and contract, finding that actual benefits will differ depending on the project’s limiting conditions. The result indicates ample opportunity for the advantages of the BIM-GIS-IoT-based excavated soil recycling system in the excavation project.

A numerical simulation of the hysteresis performance of corroded reinforced concrete (RC) frame columns was conducted. Moreover, the results obtained were compared with experimental data. On this basis, a degenerated three-linearity (D-TRI) restoring force model was established which could reflect the hysteresis performance of corroded RC frame columns through theoretical analysis and data fitting. Results indicated that the hysteretic bearing capacity of frame columns decreased significantly due to corrosion of the rebar. In view of the characteristics of the hysteresis curve, the plumpness of the hysteresis loop for frame columns decreased and shrinkage increased with increasing rebar corrosion. All these illustrated that the seismic energy dissipation performance of frame columns reduced but their brittleness increased. As for the features of the skeleton curve, the trends for corroded and noncorroded members were basically consistent and roughly corresponded to the features of a trilinear equivalent model. Thereby, the existing Clough hysteresis rule can be used to establish the restoring force model applicable to corroded RC frame columns based on that of the noncorroded RC members. The calculated skeleton curve and hysteresis curve of corroded RC frame columns using the D-TRI model are closer to the experimental results.

The existing recycling chain of construction and demolition waste generally considers soil inert solid waste to be sent to landfills. As the most significant component of C&D (construction and demolition) waste, excavated soil occupies approximately half of landfills. Currently, excavated soil is a big issue in China’s Pearl River Delta. This paper investigated the composition and quantity of excavated soil in Shenzhen, China. In particular, the potential market demand for critical recycled sand (a key recycled material extracted from the excavated soil) was estimated. Furthermore, the technical analysis for excavated soil recycling takes an entire excavated soil recycling process’s perspective, delving into the process flow for the excavated soil and the recycled sand’s physicomechanical properties. Then, two mainstream and legitimate models of excavated soil recycling were considered: stationary plant recycling and on-site recycling. Each model’s financial and economic viability was assessed. The financial analysis focuses on investors’ perspectives, whose primary goal is to assess their investment profitability. The economic feasibility of the excavated soil stationary plant recycling and on-site recycling models in Shenzhen were then compared via benefit and cost analysis during the lifetime of the recycling equipment. A comprehensive, complete cost calculation and investment analysis revealed that Shenzhen’s excavated soil recycling business is profitable under the current market conditions. This study investigates scaled and effective excavated soil recycling and gives a technically and economically viable reference to the global excavated soil issue.

Combining the theoretical derivation and numerical calculations, the characteristic changes of the tensile constitutive relation of corroded steel bars and their underlying mechanisms are studied. Corroded steel bars are regarded as a combination of three parts, which include uncorroded part, corroded part with variable cross section, and uniform corroded part. It is assumed that in all three parts the steel material follows a simplified trilinear constitutive relation of a mild steel material (elasticity, yielding, and hardening), from which an analytical model describing the overall tensile constitutive relation of the corroded steel bar is developed. Based on the experimental data of slotted steel bars, the validation of the present analytical model is provided. The results show that the trilinear model can give relatively accurate prediction of the characteristic parameters of corroded steel bars. The influences of corrosion rate on the mechanical properties of corroded steel bars are examined using the proposed model.

This paper proposes a novel output-only structural damage indicator by incorporating the pole-based optimal subpattern assignment distance with autoregressive models to localize and relatively assess the severity of damages for sheared structures. Autoregressive models can model dynamic systems well, while their model poles can represent the state of the dynamic systems. Structural damage generally causes changes in the dynamic characteristics (especially the natural frequency, mode shapes and damping ratio) of structures. Since the poles of the autoregressive models can solve the modal parameters of the structure, the poles have a close relationship with the modal parameters so that the changes in the poles of its autoregressive model reflect structural damages. Therefore, we can identify the damage by tracking the shifts in the dynamic system poles. The optimal subpattern assignment distance, which is the performance evaluator in multi-target tracking algorithms to measure the metric between true and estimated tracks, enables the construction of damage sensitive indicator from system poles using the Hungarian algorithm. The proposed approach has been validated with a five-story shear-building using numerical simulations and experimental verifications, which are subjected to excitations of white noise, El Centro earthquake and sinusoidal wave with frequencies sweeping, respectively; the results indicate that this approach can localize and quantify structural damages effectively in an output-only and data-driven way.