A Simplified Calculation Method of Length Adjustment of Datum Strand for the Main Cable with Small Sag

Table 5

The length adjustment of the datum strand and catwalk bearing rope.

Item	Target sag to span ratio	Target sag f0 (m)	Sag before adjusted f0 (m)	Exact solution	Perfect solution of parabola theory		Traditional simplified formula		The improved simplified formula I		The improved simplified formula II
				ΔS (mm)	ΔS (mm)	Error (%)	ΔS (mm)	Error (%)	ΔS (mm)	Error (%)	ΔS (mm)	Error (%)
Catwalk bearing rope at main span	1/11.57	73.322	73.508	86.11	85.43	−0.79	85.72	−0.45	88.32	2.56	88.43	2.69
Catwalk bearing rope at side span	1/97.87	1.950	2.136	68.89	68.94	0.07	7.14	−89.64	68.94	0.07	68.96	0.11
Datum strand at main span	1/11.08	76.914	77.147	109.91	109.22	−0.63	112.18	2.07	113.32	3.11	113.37	3.15
Datum strand at side span	1/42.29	4.599	4.821	25.17	25.16	−0.02	19.82	−21.27	25.16	−0.03	25.18	0.02