**5. Conclusions**

The current study highlighted the advantages of the proposed method using TLS and ANN algorithms for installation quality inspection for a high formwork. When conducting the inspection operation, the non-invasive method, along with full area coverage measurements, are a benefit.

Adoption of the TLS uses less labour when compared to common inspection methods, avoids any labour-related risks, and can access difficult and dangerous areas, which will save significant money and time and greatly improve the performance of the inspection process. The collected point cloud data can be effectively processed using the proposed data extraction approach in this study and can rapidly extract the important elements of the high formwork.

The conventional ANN network was optimized via GA to achieve the optimum parameters of the ANN model including: the number of hidden layers, the number of nodes at the hidden layers, the learning rate and the momentum coefficients. The model performance evaluation parameters and generated result indicate that the proposed GA-ANN model can produce accurate predictions. The generated accurate coordinates of the important points that are the cross points of the poles and ledgers facilitate the spacing calculation between two neighbouring of pole or lift height (the distance between two neighbouring ledgers).

The proposed method can provide accurate results that facilitate quality inspection, safety managemen<sup>t</sup> and decision making on the construction site. Moreover, the collected measurements can be kept properly, which facilitates further application in safety monitoring for high formwork during concrete cast-in. In addition, the study also provides an indication that measurements with tight tolerances can be achieved not only by using contact methods, but that the proposed methods using TLS outputs can also generate results with the required level of accuracy.

The benefits of the proposed method indicate that TLS can be successfully used in quality inspection and can generate accurate measurements in terms of the quantity and quality of the data points and timing. The measurements based on the proposed method are similar to the set values with acceptable error, and hence confirm the suitability of the proposed method. A successful approach for point cloud data extraction and measurements calculation can be used for other similar structures.

Furthermore, the laser scanning system can be utilized in combination with other techniques like photogrammetry to offer a hybrid method that can provide accurate measurements of the full covering area and the points of interest. TLS measurements can also be combined with BIM to vividly display the structure in real dimensions and state.

**Author Contributions:** Conceptualization, L.Z. and J.M.; methodology, L.Z.; software, L.Z.; validation, L.Z., J.M. and B.W.; resources, L.Z. and Z.L.; writing—original draft preparation, L.Z.; writing—review and editing, L.Z. and B.W.; visualization, L.Z. and H.Z. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Beijing University of Technology, gran<sup>t</sup> number 314000514121010 and 047000513201. The APC was funded by the two grants.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data can be provided upon request. **Acknowledgments:** The authors would like to thank Beijing University of Technology for its support through the research project. The authors would like to thank China Industry Associations for provide research data. In addition, I would like to thank all practitioners who contributed to this project. The authors really appreciate the reviewers of the paper for their kind advice and encouragement.

**Conflicts of Interest:** The authors declare no conflict of interest.
