Coordinate Monitoring Technology in the Process of Incremental Launching Construction of Curved Steel Box Girder Bridge

Table 3

Stress monitoring value and theoretical value of key sections of steel box girder.

Construction status	Incremental launching status	Section location and measuring point layout	Theoretical value (MPa)	Monitoring value (MPa)	Error rate (%)	Strength limit (MPa)
Condition 1	The moment of lifting jack	Vertical measuring point of section 1	25.81	21.21	−17.82	160.0
		Vertical measuring point of section 2	21.56	18.58	−13.82	160.0
		Longitudinal measuring point of section 3	23.80	22.87	−3.91	275.0
Condition 2(1)	Temporary steel pier unloaded incompletely	Vertical measuring point of section 1	85.99	93.73	9.00	160.0
Condition 2(2)	The moment of lifting jack	Vertical measuring point of section 1	75.99	75.39	−0.79	160.0
		Vertical measuring point of section 2	22.48	24.72	9.96	160.0
		Longitudinal measuring point of section 3	6.56	7.51	14.48	275.0
Condition 3	Before lowering down	Vertical measuring point of section 1	38.50	33.37	−13.32	160.0
		Vertical measuring point of section 2	36.63	34.40	−6.09	160.0
		Longitudinal measuring point of section 2	31.45	27.40	−12.88	275.0
		Vertical measuring point of section 3	34.70	29.25	−15.71	160.0
		Longitudinal measuring point of section 4	34.91	30.48	−12.69	275.0

Note. Error rate = (monitoring value − theoretical value) × 100%/theoretical value.