**3. The Proposed Method**

The proposed method used both TLS data and ANN model for evaluating installation quality for high formwork according to China building codes [8–10]. The major clauses of the building codes and regulations for the installation quality of high formwork are illustrated in Table 1. Therefore, the main tasks of the study are to evaluate the positions of the vertical poles, horizontal tubes, and diagonal bracing according to clauses i–iii, assess the longitudinal spacing of vertical pole according to clause iv, inspect the transverse spacing of vertical pole according to clause v, check the space between the two neighbour tubes (the lift height) according to clause vi, and check the position and the height of the bottom reinforcing tube according to clause vii.


**Table 1.** Classification of inspection terms.

The proposed method for installation quality assessment of high formwork is carried out in four steps. First, a small-scale high formwork model set was built in the lab and scanned to collect multi-scan data, which were then registered in a common reference system. Secondly, RGB value, symmetry of the structure and shape fitting algorithm were used to extract the poles and tubes of the model set and all the cross-points of the poles and tubes were generated. After that, the model set was positioned on a moving equipment and moved along the X, Y and Z axes, from 1 mm to 10 mm at interval 1 mm, respectively. The model set was scanned at every movement in order to collect sufficient scan data for developing an ANN model that can help to generate accurate coordinates of the cross points at the millimetre level. Finally, another small-scale high formwork model set was established in the lab to validate the efficiency of the proposed method. The flowchart of the proposed method is described in Figure 1. The details of the four steps are illustrated as follows.

**Figure 1.** Flowchart of the installation quality assessment framework for a high formwork.
